diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 22b778b96..ab3041616 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -23,25 +23,22 @@ jobs:
       - run: cd test_suite && cargo test --features unstable -- --skip ui --exact
 
   stable:
-    name: Rust stable
+    name: Rust ${{matrix.rust}}
     runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        rust: [stable, beta]
     steps:
       - uses: actions/checkout@v2
-      - uses: dtolnay/rust-toolchain@stable
+      - uses: dtolnay/rust-toolchain@master
+        with:
+          toolchain: ${{matrix.rust}}
       - run: cd serde && cargo build --features rc
       - run: cd serde && cargo build --no-default-features
       - run: cd serde_test && cargo build
       - run: cd serde_test && cargo test --features serde/derive,serde/rc
 
-  beta:
-    name: Rust beta
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@v2
-      - uses: dtolnay/rust-toolchain@beta
-      - run: cd serde && cargo build --features rc
-      - run: cd test_suite && cargo test
-
   nightly:
     name: Rust nightly ${{matrix.os == 'windows' && '(windows)' || ''}}
     runs-on: ${{matrix.os}}-latest
diff --git a/serde/Cargo.toml b/serde/Cargo.toml
index 6488d903c..9f4f5de98 100644
--- a/serde/Cargo.toml
+++ b/serde/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "serde"
-version = "1.0.125" # remember to update html_root_url and serde_derive dependency
+version = "1.0.126" # remember to update html_root_url and serde_derive dependency
 authors = ["Erick Tryzelaar <erick.tryzelaar@gmail.com>", "David Tolnay <dtolnay@gmail.com>"]
 license = "MIT OR Apache-2.0"
 description = "A generic serialization/deserialization framework"
@@ -14,7 +14,7 @@ include = ["build.rs", "src/**/*.rs", "crates-io.md", "README.md", "LICENSE-APAC
 build = "build.rs"
 
 [dependencies]
-serde_derive = { version = "=1.0.125", optional = true, path = "../serde_derive" }
+serde_derive = { version = "=1.0.126", optional = true, path = "../serde_derive" }
 
 [dev-dependencies]
 serde_derive = { version = "1.0", path = "../serde_derive" }
diff --git a/serde/src/lib.rs b/serde/src/lib.rs
index 5c07ece21..fd473b370 100644
--- a/serde/src/lib.rs
+++ b/serde/src/lib.rs
@@ -84,7 +84,7 @@
 ////////////////////////////////////////////////////////////////////////////////
 
 // Serde types in rustdoc of other crates get linked to here.
-#![doc(html_root_url = "https://docs.rs/serde/1.0.125")]
+#![doc(html_root_url = "https://docs.rs/serde/1.0.126")]
 // Support using Serde without the standard library!
 #![cfg_attr(not(feature = "std"), no_std)]
 // Unstable functionality only if the user asks for it. For tracking and
diff --git a/serde_derive/Cargo.toml b/serde_derive/Cargo.toml
index 0f6624155..d19254744 100644
--- a/serde_derive/Cargo.toml
+++ b/serde_derive/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "serde_derive"
-version = "1.0.125" # remember to update html_root_url
+version = "1.0.126" # remember to update html_root_url
 authors = ["Erick Tryzelaar <erick.tryzelaar@gmail.com>", "David Tolnay <dtolnay@gmail.com>"]
 license = "MIT OR Apache-2.0"
 description = "Macros 1.1 implementation of #[derive(Serialize, Deserialize)]"
diff --git a/serde_derive/src/bound.rs b/serde_derive/src/bound.rs
index 0949dfc5d..6d7402cb4 100644
--- a/serde_derive/src/bound.rs
+++ b/serde_derive/src/bound.rs
@@ -49,7 +49,7 @@ pub fn with_where_predicates_from_fields(
     let predicates = cont
         .data
         .all_fields()
-        .flat_map(|field| from_field(&field.attrs))
+        .filter_map(|field| from_field(&field.attrs))
         .flat_map(|predicates| predicates.to_vec());
 
     let mut generics = generics.clone();
@@ -71,7 +71,7 @@ pub fn with_where_predicates_from_variants(
 
     let predicates = variants
         .iter()
-        .flat_map(|variant| from_variant(&variant.attrs))
+        .filter_map(|variant| from_variant(&variant.attrs))
         .flat_map(|predicates| predicates.to_vec());
 
     let mut generics = generics.clone();
diff --git a/serde_derive/src/dummy.rs b/serde_derive/src/dummy.rs
index 9a4e5f085..29de26012 100644
--- a/serde_derive/src/dummy.rs
+++ b/serde_derive/src/dummy.rs
@@ -23,7 +23,7 @@ pub fn wrap_in_const(
             use #path as _serde;
         },
         None => quote! {
-            #[allow(rust_2018_idioms, clippy::useless_attribute)]
+            #[allow(unused_extern_crates, clippy::useless_attribute)]
             extern crate serde as _serde;
         },
     };
diff --git a/serde_derive/src/lib.rs b/serde_derive/src/lib.rs
index 84728f123..8daa36e70 100644
--- a/serde_derive/src/lib.rs
+++ b/serde_derive/src/lib.rs
@@ -13,11 +13,13 @@
 //!
 //! [https://serde.rs/derive.html]: https://serde.rs/derive.html
 
-#![doc(html_root_url = "https://docs.rs/serde_derive/1.0.125")]
+#![doc(html_root_url = "https://docs.rs/serde_derive/1.0.126")]
 #![allow(unknown_lints, bare_trait_objects)]
 #![deny(clippy::all, clippy::pedantic)]
 // Ignored clippy lints
 #![allow(
+    // clippy false positive: https://github.com/rust-lang/rust-clippy/issues/7054
+    clippy::branches_sharing_code,
     clippy::cognitive_complexity,
     clippy::enum_variant_names,
     // clippy bug: https://github.com/rust-lang/rust-clippy/issues/6797
@@ -37,12 +39,13 @@
     clippy::checked_conversions,
     clippy::doc_markdown,
     clippy::enum_glob_use,
-    clippy::filter_map,
     clippy::indexing_slicing,
     clippy::items_after_statements,
     clippy::let_underscore_drop,
     clippy::map_err_ignore,
     clippy::match_same_arms,
+    // clippy bug: https://github.com/rust-lang/rust-clippy/issues/6984
+    clippy::match_wildcard_for_single_variants,
     clippy::module_name_repetitions,
     clippy::must_use_candidate,
     clippy::option_if_let_else,
diff --git a/serde_derive_internals/Cargo.toml b/serde_derive_internals/Cargo.toml
index 81c9e20d5..fea1b474e 100644
--- a/serde_derive_internals/Cargo.toml
+++ b/serde_derive_internals/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "serde_derive_internals"
-version = "0.25.0" # remember to update html_root_url
+version = "0.26.0" # remember to update html_root_url
 authors = ["Erick Tryzelaar <erick.tryzelaar@gmail.com>", "David Tolnay <dtolnay@gmail.com>"]
 license = "MIT OR Apache-2.0"
 description = "AST representation used by Serde derive macros. Unstable."
diff --git a/serde_derive_internals/build.rs b/serde_derive_internals/build.rs
new file mode 100644
index 000000000..b2a2d04ab
--- /dev/null
+++ b/serde_derive_internals/build.rs
@@ -0,0 +1,12 @@
+use std::path::Path;
+
+fn main() {
+    // Sometimes on Windows the git checkout does not correctly wire up the
+    // symlink from serde_derive_internals/src to serde_derive/src/internals.
+    // When this happens we'll just build based on relative paths within the git
+    // repo.
+    let mod_behind_symlink = Path::new("src/mod.rs");
+    if !mod_behind_symlink.exists() {
+        println!("cargo:rustc-cfg=serde_build_from_git");
+    }
+}
diff --git a/serde_derive_internals/lib.rs b/serde_derive_internals/lib.rs
index fe67d1f46..1f8ff187b 100644
--- a/serde_derive_internals/lib.rs
+++ b/serde_derive_internals/lib.rs
@@ -1,4 +1,4 @@
-#![doc(html_root_url = "https://docs.rs/serde_derive_internals/0.25.0")]
+#![doc(html_root_url = "https://docs.rs/serde_derive_internals/0.26.0")]
 #![allow(unknown_lints, bare_trait_objects)]
 #![deny(clippy::all, clippy::pedantic)]
 // Ignored clippy lints
@@ -22,6 +22,8 @@
     clippy::items_after_statements,
     clippy::let_underscore_drop,
     clippy::match_same_arms,
+    // clippy bug: https://github.com/rust-lang/rust-clippy/issues/6984
+    clippy::match_wildcard_for_single_variants,
     clippy::missing_errors_doc,
     clippy::module_name_repetitions,
     clippy::must_use_candidate,
@@ -38,7 +40,8 @@ extern crate syn;
 extern crate proc_macro2;
 extern crate quote;
 
-#[path = "src/mod.rs"]
+#[cfg_attr(serde_build_from_git, path = "../serde_derive/src/internals/mod.rs")]
+#[cfg_attr(not(serde_build_from_git), path = "src/mod.rs")]
 mod internals;
 
 pub use internals::*;
diff --git a/serde_test/Cargo.toml b/serde_test/Cargo.toml
index 68028c79e..0237d1816 100644
--- a/serde_test/Cargo.toml
+++ b/serde_test/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "serde_test"
-version = "1.0.125" # remember to update html_root_url
+version = "1.0.126" # remember to update html_root_url
 authors = ["Erick Tryzelaar <erick.tryzelaar@gmail.com>", "David Tolnay <dtolnay@gmail.com>"]
 license = "MIT OR Apache-2.0"
 description = "Token De/Serializer for testing De/Serialize implementations"
diff --git a/serde_test/src/lib.rs b/serde_test/src/lib.rs
index a925c916d..c29d31741 100644
--- a/serde_test/src/lib.rs
+++ b/serde_test/src/lib.rs
@@ -144,7 +144,7 @@
 //! # }
 //! ```
 
-#![doc(html_root_url = "https://docs.rs/serde_test/1.0.125")]
+#![doc(html_root_url = "https://docs.rs/serde_test/1.0.126")]
 #![cfg_attr(feature = "cargo-clippy", allow(renamed_and_removed_lints))]
 #![cfg_attr(feature = "cargo-clippy", deny(clippy, clippy_pedantic))]
 // Ignored clippy lints
@@ -153,6 +153,7 @@
 #![cfg_attr(
     feature = "cargo-clippy",
     allow(
+        cloned_instead_of_copied,
         empty_line_after_outer_attr,
         missing_docs_in_private_items,
         missing_panics_doc,
diff --git a/test_suite/tests/expand/de_enum.expanded.rs b/test_suite/tests/expand/de_enum.expanded.rs
index 0aa879e75..4ea3b8383 100644
--- a/test_suite/tests/expand/de_enum.expanded.rs
+++ b/test_suite/tests/expand/de_enum.expanded.rs
@@ -10,7 +10,7 @@ enum DeEnum<B, C, D> {
 #[doc(hidden)]
 #[allow(non_upper_case_globals, unused_attributes, unused_qualifications)]
 const _: () = {
-    #[allow(rust_2018_idioms, clippy::useless_attribute)]
+    #[allow(unused_extern_crates, clippy::useless_attribute)]
     extern crate serde as _serde;
     #[automatically_derived]
     impl<B, C, D> _serde::Serialize for DeEnum<B, C, D>
@@ -265,7 +265,7 @@ const _: () = {
 #[doc(hidden)]
 #[allow(non_upper_case_globals, unused_attributes, unused_qualifications)]
 const _: () = {
-    #[allow(rust_2018_idioms, clippy::useless_attribute)]
+    #[allow(unused_extern_crates, clippy::useless_attribute)]
     extern crate serde as _serde;
     #[automatically_derived]
     impl<'de, B, C, D> _serde::Deserialize<'de> for DeEnum<B, C, D>
diff --git a/test_suite/tests/expand/default_ty_param.expanded.rs b/test_suite/tests/expand/default_ty_param.expanded.rs
index d24ce254b..829e65e8e 100644
--- a/test_suite/tests/expand/default_ty_param.expanded.rs
+++ b/test_suite/tests/expand/default_ty_param.expanded.rs
@@ -11,7 +11,7 @@ struct DefaultTyParam<T: AssociatedType<X = i32> = i32> {
 #[doc(hidden)]
 #[allow(non_upper_case_globals, unused_attributes, unused_qualifications)]
 const _: () = {
-    #[allow(rust_2018_idioms, clippy::useless_attribute)]
+    #[allow(unused_extern_crates, clippy::useless_attribute)]
     extern crate serde as _serde;
     #[automatically_derived]
     impl<T: AssociatedType<X = i32>> _serde::Serialize for DefaultTyParam<T> {
@@ -49,7 +49,7 @@ const _: () = {
 #[doc(hidden)]
 #[allow(non_upper_case_globals, unused_attributes, unused_qualifications)]
 const _: () = {
-    #[allow(rust_2018_idioms, clippy::useless_attribute)]
+    #[allow(unused_extern_crates, clippy::useless_attribute)]
     extern crate serde as _serde;
     #[automatically_derived]
     impl<'de, T: AssociatedType<X = i32>> _serde::Deserialize<'de> for DefaultTyParam<T> {
diff --git a/test_suite/tests/expand/generic_enum.expanded.rs b/test_suite/tests/expand/generic_enum.expanded.rs
index d2d8658d7..a4ad31094 100644
--- a/test_suite/tests/expand/generic_enum.expanded.rs
+++ b/test_suite/tests/expand/generic_enum.expanded.rs
@@ -8,7 +8,7 @@ pub enum GenericEnum<T, U> {
 #[doc(hidden)]
 #[allow(non_upper_case_globals, unused_attributes, unused_qualifications)]
 const _: () = {
-    #[allow(rust_2018_idioms, clippy::useless_attribute)]
+    #[allow(unused_extern_crates, clippy::useless_attribute)]
     extern crate serde as _serde;
     #[automatically_derived]
     impl<T, U> _serde::Serialize for GenericEnum<T, U>
@@ -114,7 +114,7 @@ const _: () = {
 #[doc(hidden)]
 #[allow(non_upper_case_globals, unused_attributes, unused_qualifications)]
 const _: () = {
-    #[allow(rust_2018_idioms, clippy::useless_attribute)]
+    #[allow(unused_extern_crates, clippy::useless_attribute)]
     extern crate serde as _serde;
     #[automatically_derived]
     impl<'de, T, U> _serde::Deserialize<'de> for GenericEnum<T, U>
diff --git a/test_suite/tests/expand/generic_struct.expanded.rs b/test_suite/tests/expand/generic_struct.expanded.rs
index d57460c3b..bb16dc3b2 100644
--- a/test_suite/tests/expand/generic_struct.expanded.rs
+++ b/test_suite/tests/expand/generic_struct.expanded.rs
@@ -5,7 +5,7 @@ pub struct GenericStruct<T> {
 #[doc(hidden)]
 #[allow(non_upper_case_globals, unused_attributes, unused_qualifications)]
 const _: () = {
-    #[allow(rust_2018_idioms, clippy::useless_attribute)]
+    #[allow(unused_extern_crates, clippy::useless_attribute)]
     extern crate serde as _serde;
     #[automatically_derived]
     impl<T> _serde::Serialize for GenericStruct<T>
@@ -42,7 +42,7 @@ const _: () = {
 #[doc(hidden)]
 #[allow(non_upper_case_globals, unused_attributes, unused_qualifications)]
 const _: () = {
-    #[allow(rust_2018_idioms, clippy::useless_attribute)]
+    #[allow(unused_extern_crates, clippy::useless_attribute)]
     extern crate serde as _serde;
     #[automatically_derived]
     impl<'de, T> _serde::Deserialize<'de> for GenericStruct<T>
@@ -410,7 +410,7 @@ pub struct GenericNewTypeStruct<T>(T);
 #[doc(hidden)]
 #[allow(non_upper_case_globals, unused_attributes, unused_qualifications)]
 const _: () = {
-    #[allow(rust_2018_idioms, clippy::useless_attribute)]
+    #[allow(unused_extern_crates, clippy::useless_attribute)]
     extern crate serde as _serde;
     #[automatically_derived]
     impl<T> _serde::Serialize for GenericNewTypeStruct<T>
@@ -435,7 +435,7 @@ const _: () = {
 #[doc(hidden)]
 #[allow(non_upper_case_globals, unused_attributes, unused_qualifications)]
 const _: () = {
-    #[allow(rust_2018_idioms, clippy::useless_attribute)]
+    #[allow(unused_extern_crates, clippy::useless_attribute)]
     extern crate serde as _serde;
     #[automatically_derived]
     impl<'de, T> _serde::Deserialize<'de> for GenericNewTypeStruct<T>
diff --git a/test_suite/tests/expand/generic_tuple_struct.expanded.rs b/test_suite/tests/expand/generic_tuple_struct.expanded.rs
index f387b6af4..7012f9f40 100644
--- a/test_suite/tests/expand/generic_tuple_struct.expanded.rs
+++ b/test_suite/tests/expand/generic_tuple_struct.expanded.rs
@@ -3,7 +3,7 @@ pub struct GenericTupleStruct<T, U>(T, U);
 #[doc(hidden)]
 #[allow(non_upper_case_globals, unused_attributes, unused_qualifications)]
 const _: () = {
-    #[allow(rust_2018_idioms, clippy::useless_attribute)]
+    #[allow(unused_extern_crates, clippy::useless_attribute)]
     extern crate serde as _serde;
     #[automatically_derived]
     impl<'de, T, U> _serde::Deserialize<'de> for GenericTupleStruct<T, U>
diff --git a/test_suite/tests/expand/lifetimes.expanded.rs b/test_suite/tests/expand/lifetimes.expanded.rs
index f8ec1df75..cf2f00811 100644
--- a/test_suite/tests/expand/lifetimes.expanded.rs
+++ b/test_suite/tests/expand/lifetimes.expanded.rs
@@ -8,7 +8,7 @@ enum Lifetimes<'a> {
 #[doc(hidden)]
 #[allow(non_upper_case_globals, unused_attributes, unused_qualifications)]
 const _: () = {
-    #[allow(rust_2018_idioms, clippy::useless_attribute)]
+    #[allow(unused_extern_crates, clippy::useless_attribute)]
     extern crate serde as _serde;
     #[automatically_derived]
     impl<'a> _serde::Serialize for Lifetimes<'a> {
@@ -95,7 +95,7 @@ const _: () = {
 #[doc(hidden)]
 #[allow(non_upper_case_globals, unused_attributes, unused_qualifications)]
 const _: () = {
-    #[allow(rust_2018_idioms, clippy::useless_attribute)]
+    #[allow(unused_extern_crates, clippy::useless_attribute)]
     extern crate serde as _serde;
     #[automatically_derived]
     impl<'de, 'a> _serde::Deserialize<'de> for Lifetimes<'a> {
diff --git a/test_suite/tests/expand/named_map.expanded.rs b/test_suite/tests/expand/named_map.expanded.rs
index 1a621b57f..e30ac34e4 100644
--- a/test_suite/tests/expand/named_map.expanded.rs
+++ b/test_suite/tests/expand/named_map.expanded.rs
@@ -7,7 +7,7 @@ struct SerNamedMap<'a, 'b, A: 'a, B: 'b, C> {
 #[doc(hidden)]
 #[allow(non_upper_case_globals, unused_attributes, unused_qualifications)]
 const _: () = {
-    #[allow(rust_2018_idioms, clippy::useless_attribute)]
+    #[allow(unused_extern_crates, clippy::useless_attribute)]
     extern crate serde as _serde;
     #[automatically_derived]
     impl<'a, 'b, A: 'a, B: 'b, C> _serde::Serialize for SerNamedMap<'a, 'b, A, B, C>
@@ -63,7 +63,7 @@ struct DeNamedMap<A, B, C> {
 #[doc(hidden)]
 #[allow(non_upper_case_globals, unused_attributes, unused_qualifications)]
 const _: () = {
-    #[allow(rust_2018_idioms, clippy::useless_attribute)]
+    #[allow(unused_extern_crates, clippy::useless_attribute)]
     extern crate serde as _serde;
     #[automatically_derived]
     impl<'de, A, B, C> _serde::Deserialize<'de> for DeNamedMap<A, B, C>
diff --git a/test_suite/tests/expand/named_tuple.expanded.rs b/test_suite/tests/expand/named_tuple.expanded.rs
index 707ca0762..be083f633 100644
--- a/test_suite/tests/expand/named_tuple.expanded.rs
+++ b/test_suite/tests/expand/named_tuple.expanded.rs
@@ -3,7 +3,7 @@ struct SerNamedTuple<'a, 'b, A: 'a, B: 'b, C>(&'a A, &'b mut B, C);
 #[doc(hidden)]
 #[allow(non_upper_case_globals, unused_attributes, unused_qualifications)]
 const _: () = {
-    #[allow(rust_2018_idioms, clippy::useless_attribute)]
+    #[allow(unused_extern_crates, clippy::useless_attribute)]
     extern crate serde as _serde;
     #[automatically_derived]
     impl<'a, 'b, A: 'a, B: 'b, C> _serde::Serialize for SerNamedTuple<'a, 'b, A, B, C>
@@ -55,7 +55,7 @@ struct DeNamedTuple<A, B, C>(A, B, C);
 #[doc(hidden)]
 #[allow(non_upper_case_globals, unused_attributes, unused_qualifications)]
 const _: () = {
-    #[allow(rust_2018_idioms, clippy::useless_attribute)]
+    #[allow(unused_extern_crates, clippy::useless_attribute)]
     extern crate serde as _serde;
     #[automatically_derived]
     impl<'de, A, B, C> _serde::Deserialize<'de> for DeNamedTuple<A, B, C>
diff --git a/test_suite/tests/expand/named_unit.expanded.rs b/test_suite/tests/expand/named_unit.expanded.rs
index 44329246d..87876b771 100644
--- a/test_suite/tests/expand/named_unit.expanded.rs
+++ b/test_suite/tests/expand/named_unit.expanded.rs
@@ -3,7 +3,7 @@ struct NamedUnit;
 #[doc(hidden)]
 #[allow(non_upper_case_globals, unused_attributes, unused_qualifications)]
 const _: () = {
-    #[allow(rust_2018_idioms, clippy::useless_attribute)]
+    #[allow(unused_extern_crates, clippy::useless_attribute)]
     extern crate serde as _serde;
     #[automatically_derived]
     impl _serde::Serialize for NamedUnit {
@@ -21,7 +21,7 @@ const _: () = {
 #[doc(hidden)]
 #[allow(non_upper_case_globals, unused_attributes, unused_qualifications)]
 const _: () = {
-    #[allow(rust_2018_idioms, clippy::useless_attribute)]
+    #[allow(unused_extern_crates, clippy::useless_attribute)]
     extern crate serde as _serde;
     #[automatically_derived]
     impl<'de> _serde::Deserialize<'de> for NamedUnit {
diff --git a/test_suite/tests/expand/ser_enum.expanded.rs b/test_suite/tests/expand/ser_enum.expanded.rs
index 40b45e07f..b0a83ca3f 100644
--- a/test_suite/tests/expand/ser_enum.expanded.rs
+++ b/test_suite/tests/expand/ser_enum.expanded.rs
@@ -13,7 +13,7 @@ where
 #[doc(hidden)]
 #[allow(non_upper_case_globals, unused_attributes, unused_qualifications)]
 const _: () = {
-    #[allow(rust_2018_idioms, clippy::useless_attribute)]
+    #[allow(unused_extern_crates, clippy::useless_attribute)]
     extern crate serde as _serde;
     #[automatically_derived]
     impl<'a, B: 'a, C: 'a, D> _serde::Serialize for SerEnum<'a, B, C, D>
diff --git a/test_suite/tests/expand/void.expanded.rs b/test_suite/tests/expand/void.expanded.rs
index 65c3d2c60..35e6763d7 100644
--- a/test_suite/tests/expand/void.expanded.rs
+++ b/test_suite/tests/expand/void.expanded.rs
@@ -3,7 +3,7 @@ enum Void {}
 #[doc(hidden)]
 #[allow(non_upper_case_globals, unused_attributes, unused_qualifications)]
 const _: () = {
-    #[allow(rust_2018_idioms, clippy::useless_attribute)]
+    #[allow(unused_extern_crates, clippy::useless_attribute)]
     extern crate serde as _serde;
     #[automatically_derived]
     impl _serde::Serialize for Void {
@@ -21,7 +21,7 @@ const _: () = {
 #[doc(hidden)]
 #[allow(non_upper_case_globals, unused_attributes, unused_qualifications)]
 const _: () = {
-    #[allow(rust_2018_idioms, clippy::useless_attribute)]
+    #[allow(unused_extern_crates, clippy::useless_attribute)]
     extern crate serde as _serde;
     #[automatically_derived]
     impl<'de> _serde::Deserialize<'de> for Void {
diff --git a/test_suite/tests/test_gen.rs b/test_suite/tests/test_gen.rs
index 002885ead..309b164b1 100644
--- a/test_suite/tests/test_gen.rs
+++ b/test_suite/tests/test_gen.rs
@@ -3,7 +3,6 @@
 // types involved.
 
 #![deny(warnings)]
-#![cfg_attr(feature = "unstable", feature(non_ascii_idents))]
 #![allow(
     unknown_lints,
     mixed_script_confusables,
@@ -267,7 +266,6 @@ fn test_gen() {
     }
     assert::<EmptyEnumVariant>();
 
-    #[cfg(feature = "unstable")]
     #[derive(Serialize, Deserialize)]
     struct NonAsciiIdents {
         σ: f64,
diff --git a/test_suite/tests/test_macros.rs b/test_suite/tests/test_macros.rs
index a6f130272..fea59e0e6 100644
--- a/test_suite/tests/test_macros.rs
+++ b/test_suite/tests/test_macros.rs
@@ -1923,7 +1923,7 @@ fn test_internally_tagged_newtype_variant_containing_unit_struct() {
     );
 }
 
-#[deny(safe_packed_borrows)]
+#[deny(unaligned_references)]
 #[test]
 fn test_packed_struct_can_derive_serialize() {
     #[derive(Copy, Clone, Serialize)]