diff --git a/azure-pipelines.yml b/azure-pipelines.yml
index 02136c45fd0..2207a4792eb 100644
--- a/azure-pipelines.yml
+++ b/azure-pipelines.yml
@@ -233,6 +233,19 @@ jobs:
         - script: eng\CIBuild.cmd -configuration Release -noSign /p:DotNetBuildFromSource=true /p:FSharpSourceBuild=true
           displayName: Build
 
+      # Up-to-date
+      - job: UpToDate_Windows
+        pool:
+          vmImage: windows-2019
+        steps:
+        - checkout: self
+          clean: true
+        - task: PowerShell@2
+          displayName: Run up-to-date build check
+          inputs:
+            filePath: eng\tests\UpToDate.ps1
+            arguments: -configuration $(_BuildConfig) -ci -binaryLog
+
 #---------------------------------------------------------------------------------------------------------------------#
 #                                                    FCS builds                                                       #
 #---------------------------------------------------------------------------------------------------------------------#
diff --git a/eng/tests/UpToDate.ps1 b/eng/tests/UpToDate.ps1
new file mode 100644
index 00000000000..a7e50a26d60
--- /dev/null
+++ b/eng/tests/UpToDate.ps1
@@ -0,0 +1,70 @@
+# This script verifies that subsequent calls to `Build.cmd` don't cause assemblies to be unnecessarily rebuilt.
+
+[CmdletBinding(PositionalBinding=$false)]
+param (
+    [string][Alias('c')]$configuration = "Debug",
+    [parameter(ValueFromRemainingArguments=$true)][string[]]$properties
+)
+
+Set-StrictMode -version 2.0
+$ErrorActionPreference = "Stop"
+
+try {
+    $RepoRoot = Join-Path $PSScriptRoot ".." | Join-Path -ChildPath ".." -Resolve
+    $BuildScript = Join-Path $RepoRoot "Build.cmd"
+
+    # do first build
+    & $BuildScript -configuration $configuration @properties
+    if ($LASTEXITCODE -ne 0) {
+        Write-Host "Error running first build."
+        exit 1
+    }
+
+    # gather assembly timestamps
+    $ArtifactsBinDir = Join-Path $RepoRoot "artifacts" | Join-Path -ChildPath "bin" -Resolve
+    $FSharpAssemblyDirs = Get-ChildItem -Path $ArtifactsBinDir -Filter "FSharp.*"
+    $FSharpAssemblyPaths = $FSharpAssemblyDirs | ForEach-Object { Get-ChildItem -Path (Join-Path $ArtifactsBinDir $_) -Recurse -Filter "$_.dll" } | ForEach-Object { $_.FullName }
+
+    $InitialAssembliesAndTimes = @{}
+    foreach ($asm in $FSharpAssemblyPaths) {
+        $LastWriteTime = (Get-Item $asm).LastWriteTimeUtc
+        $InitialAssembliesAndTimes.Add($asm, $LastWriteTime)
+    }
+
+    $InitialCompiledCount = $FSharpAssemblyPaths.Length
+
+    # build again
+    & $BuildScript -configuration $configuration @properties
+    if ($LASTEXITCODE -ne 0) {
+        Write-Host "Error running second build."
+        exit 1
+    }
+
+    # gather assembly timestamps again
+    $FinalAssembliesAndTimes = @{}
+    foreach ($asm in $FSharpAssemblyPaths) {
+        $LastWriteTime = (Get-Item $asm).LastWriteTimeUtc
+        $FinalAssembliesAndTimes.Add($asm, $LastWriteTime)
+    }
+
+    # validate that assembly timestamps haven't changed
+    $RecompiledFiles = @()
+    foreach ($asm in $InitialAssembliesAndTimes.keys) {
+        $InitialTime = $InitialAssembliesAndTimes[$asm]
+        $FinalTime = $FinalAssembliesAndTimes[$asm]
+        if ($InitialTime -ne $FinalTime) {
+            $RecompiledFiles += $asm
+        }
+    }
+
+    $RecompiledCount = $RecompiledFiles.Length
+    Write-Host "$RecompiledCount of $InitialCompiledCount assemblies were re-compiled"
+    $RecompiledFiles | ForEach-Object { Write-Host "    $_" }
+    exit $RecompiledCount
+}
+catch {
+    Write-Host $_
+    Write-Host $_.Exception
+    Write-Host $_.ScriptStackTrace
+    exit 1
+}
diff --git a/src/fsharp/service/ServiceAnalysis.fs b/src/fsharp/service/ServiceAnalysis.fs
index f66d372bc28..e4f942b657a 100644
--- a/src/fsharp/service/ServiceAnalysis.fs
+++ b/src/fsharp/service/ServiceAnalysis.fs
@@ -99,17 +99,27 @@ module UnusedOpens =
              | :? FSharpMemberOrFunctionOrValue as fv when fv.IsExtensionMember -> 
                 // Extension members should be taken into account even though they have a prefix (as they do most of the time)
                 true
+
              | :? FSharpMemberOrFunctionOrValue as fv when not fv.IsModuleValueOrMember -> 
                 // Local values can be ignored
                 false
+
              | :? FSharpMemberOrFunctionOrValue when su.IsFromDefinition -> 
                 // Value definitions should be ignored
                 false
+
              | :? FSharpGenericParameter -> 
                 // Generic parameters can be ignored, they never come into scope via 'open'
                 false
+
              | :? FSharpUnionCase when su.IsFromDefinition -> 
                 false
+
+             | :? FSharpField as field when
+                     field.DeclaringEntity.IsSome && field.DeclaringEntity.Value.IsFSharpRecord ->
+                // Record fields are used in name resolution
+                true
+
              | _ ->
                 // For the rest of symbols we pick only those which are the first part of a long ident, because it's they which are
                 // contained in opened namespaces / modules. For example, we pick `IO` from long ident `IO.File.OpenWrite` because
diff --git a/src/fsharp/symbols/SymbolPatterns.fs b/src/fsharp/symbols/SymbolPatterns.fs
index 2265682692b..6c2286b4095 100644
--- a/src/fsharp/symbols/SymbolPatterns.fs
+++ b/src/fsharp/symbols/SymbolPatterns.fs
@@ -132,8 +132,8 @@ module Symbol =
 #endif
     let (|Enum|_|) (entity: FSharpEntity) = if entity.IsEnum then Some() else None
 
-    let (|Tuple|_|) (ty: FSharpType option) = 
-        ty |> Option.bind (fun ty -> if ty.IsTupleType then Some() else None)
+    let (|Tuple|_|) (ty: FSharpType) =
+        if ty.IsTupleType then Some() else None
 
     let (|RefCell|_|) (ty: FSharpType) = 
         match getAbbreviatedType ty with
diff --git a/src/fsharp/symbols/SymbolPatterns.fsi b/src/fsharp/symbols/SymbolPatterns.fsi
index c4c242270cd..ca3659f34d6 100644
--- a/src/fsharp/symbols/SymbolPatterns.fsi
+++ b/src/fsharp/symbols/SymbolPatterns.fsi
@@ -37,7 +37,7 @@ module public Symbol =
     val (|ProvidedAndErasedType|_|) : FSharpEntity -> unit option
 #endif
     val (|Enum|_|) : FSharpEntity -> unit option
-    val (|Tuple|_|) : FSharpType option -> unit option
+    val (|Tuple|_|) : FSharpType -> unit option
     val (|RefCell|_|) : FSharpType -> unit option
     val (|FunctionType|_|) : FSharpType -> unit option
     val (|Pattern|_|) : FSharpSymbol -> unit option
diff --git a/tests/service/ProjectAnalysisTests.fs b/tests/service/ProjectAnalysisTests.fs
index 08f19cbe708..9dca0cd56f6 100644
--- a/tests/service/ProjectAnalysisTests.fs
+++ b/tests/service/ProjectAnalysisTests.fs
@@ -5523,6 +5523,14 @@ type UseTheThings(i:int) =
     member x.UseSomeUsedModuleContainingActivePattern(ActivePattern g) = g
     member x.UseSomeUsedModuleContainingExtensionMember() = (3).Q
     member x.UseSomeUsedModuleContainingUnion() = A
+
+module M1 =
+    type R = { Field: int }
+
+module M2 =
+    open M1
+
+    let foo x = x.Field
 """
     let fileSource1 = FSharp.Compiler.Text.SourceText.ofString fileSource1Text
     File.WriteAllText(fileName1, fileSource1Text)