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-rw-r--r--tests/codegen-units/item-collection/closures.rs6
-rw-r--r--tests/codegen-units/item-collection/drop-glue-eager.rs56
-rw-r--r--tests/debuginfo/thread.rs8
-rw-r--r--tests/incremental/overlapping-impls-in-new-solver-issue-135514.rs40
-rw-r--r--tests/run-make/rustdoc-default-output/output-default.stdout3
-rw-r--r--tests/rustdoc-gui/links-color.goml6
-rw-r--r--tests/rustdoc-js-std/return-based-sort.js30
-rw-r--r--tests/rustdoc-json/return_private.rs2
-rw-r--r--tests/rustdoc/jump-to-def-pats.rs52
-rw-r--r--tests/ui/associated-types/issue-91231.rs2
-rw-r--r--tests/ui/async-await/async-closures/fn-exception-target-features.stderr5
-rw-r--r--tests/ui/attributes/key-value-expansion.rs2
-rw-r--r--tests/ui/borrowck/issue-92157.rs2
-rw-r--r--tests/ui/closures/binder/nested-closures-regions.stderr4
-rw-r--r--tests/ui/coherence/coherence-negative-impls-copy.rs2
-rw-r--r--tests/ui/conditional-compilation/cfg_accessible-not_sure.rs2
-rw-r--r--tests/ui/const-generics/type-mismatch-in-nested-goal.current.stderr45
-rw-r--r--tests/ui/const-generics/type-mismatch-in-nested-goal.next.stderr45
-rw-r--r--tests/ui/const-generics/type-mismatch-in-nested-goal.rs17
-rw-r--r--tests/ui/consts/const-block-const-bound.rs4
-rw-r--r--tests/ui/consts/const-block-const-bound.stderr4
-rw-r--r--tests/ui/consts/const-eval/validation-ice-extern-type-field.rs2
-rw-r--r--tests/ui/consts/issue-94675.rs6
-rw-r--r--tests/ui/consts/issue-94675.stderr2
-rw-r--r--tests/ui/consts/promoted-const-drop.rs2
-rw-r--r--tests/ui/consts/promoted_const_call.rs16
-rw-r--r--tests/ui/consts/promoted_const_call.stderr37
-rw-r--r--tests/ui/delegation/glob-non-impl.rs2
-rw-r--r--tests/ui/enum-discriminant/eval-error.rs37
-rw-r--r--tests/ui/enum-discriminant/eval-error.stderr51
-rw-r--r--tests/ui/extern/extern-type-diag-not-similar.rs4
-rw-r--r--tests/ui/extern/issue-10025.rs2
-rw-r--r--tests/ui/extern/issue-95829.rs2
-rw-r--r--tests/ui/extern/issue-95829.stderr8
-rw-r--r--tests/ui/extern/not-in-block.rs1
-rw-r--r--tests/ui/extern/not-in-block.stderr4
-rw-r--r--tests/ui/foreign/issue-91370-foreign-fn-block-impl.rs2
-rw-r--r--tests/ui/foreign/issue-91370-foreign-fn-block-impl.stderr4
-rw-r--r--tests/ui/impl-trait/normalize-tait-in-const.rs3
-rw-r--r--tests/ui/impl-trait/normalize-tait-in-const.stderr6
-rw-r--r--tests/ui/invalid/invalid-rustc_legacy_const_generics-arguments.rs2
-rw-r--r--tests/ui/invalid_dispatch_from_dyn_impls.stderr4
-rw-r--r--tests/ui/issues/issue-25901.rs2
-rw-r--r--tests/ui/issues/issue-25901.stderr13
-rw-r--r--tests/ui/layout/base-layout-is-sized-ice-123078.rs1
-rw-r--r--tests/ui/layout/base-layout-is-sized-ice-123078.stderr14
-rw-r--r--tests/ui/layout/debug.stderr2
-rw-r--r--tests/ui/link-native-libs/issue-109144.rs2
-rw-r--r--tests/ui/link-native-libs/suggest-libname-only-1.stderr10
-rw-r--r--tests/ui/link-native-libs/suggest-libname-only-2.stderr10
-rw-r--r--tests/ui/lint/function-item-references.rs2
-rw-r--r--tests/ui/lint/lint-ctypes.rs2
-rw-r--r--tests/ui/lint/lint-ctypes.stderr4
-rw-r--r--tests/ui/macros/issue-68060.rs2
-rw-r--r--tests/ui/macros/issue-68060.stderr10
-rw-r--r--tests/ui/nll/closure-requirements/escape-argument-callee.stderr2
-rw-r--r--tests/ui/nll/closure-requirements/propagate-approximated-shorter-to-static-comparing-against-free.stderr2
-rw-r--r--tests/ui/nll/closure-requirements/propagate-fail-to-approximate-longer-no-bounds.stderr4
-rw-r--r--tests/ui/nll/closure-requirements/propagate-fail-to-approximate-longer-wrong-bounds.stderr4
-rw-r--r--tests/ui/offset-of/offset-of-dst-field.rs2
-rw-r--r--tests/ui/parser/bad-fn-ptr-qualifier.fixed8
-rw-r--r--tests/ui/parser/bad-fn-ptr-qualifier.rs8
-rw-r--r--tests/ui/parser/bad-fn-ptr-qualifier.stderr32
-rw-r--r--tests/ui/parser/bad-lit-suffixes.rs4
-rw-r--r--tests/ui/parser/bad-lit-suffixes.stderr16
-rw-r--r--tests/ui/parser/issues/issue-87217-keyword-order/wrong-unsafe.rs1
-rw-r--r--tests/ui/parser/issues/issue-87217-keyword-order/wrong-unsafe.stderr2
-rw-r--r--tests/ui/parser/item-kw-case-mismatch.fixed2
-rw-r--r--tests/ui/parser/item-kw-case-mismatch.rs2
-rw-r--r--tests/ui/parser/item-kw-case-mismatch.stderr8
-rw-r--r--tests/ui/parser/lit-err-in-macro.rs2
-rw-r--r--tests/ui/parser/lit-err-in-macro.stderr14
-rw-r--r--tests/ui/parser/recover/recover-const-async-fn-ptr.rs8
-rw-r--r--tests/ui/parser/recover/recover-const-async-fn-ptr.stderr32
-rw-r--r--tests/ui/parser/recover/recover-fn-ptr-with-generics.rs2
-rw-r--r--tests/ui/parser/recover/recover-fn-ptr-with-generics.stderr16
-rw-r--r--tests/ui/parser/recover/recover-missing-semi-before-item.fixed2
-rw-r--r--tests/ui/parser/recover/recover-missing-semi-before-item.rs2
-rw-r--r--tests/ui/parser/recover/recover-missing-semi-before-item.stderr2
-rw-r--r--tests/ui/privacy/sysroot-private.default.stderr39
-rw-r--r--tests/ui/privacy/sysroot-private.rs42
-rw-r--r--tests/ui/privacy/sysroot-private.rustc_private_enabled.stderr39
-rw-r--r--tests/ui/proc-macro/inner-attrs.stderr10
-rw-r--r--tests/ui/proc-macro/issue-66286.rs2
-rw-r--r--tests/ui/proc-macro/issue-66286.stderr10
-rw-r--r--tests/ui/rfcs/rfc-2396-target_feature-11/fn-ptr.stderr7
-rw-r--r--tests/ui/rfcs/rfc-2396-target_feature-11/fn-traits.rs6
-rw-r--r--tests/ui/rfcs/rfc-2396-target_feature-11/fn-traits.stderr24
-rw-r--r--tests/ui/rfcs/rfc-2396-target_feature-11/trait-impl.rs1
-rw-r--r--tests/ui/rfcs/rfc-2396-target_feature-11/trait-impl.stderr19
-rw-r--r--tests/ui/rfcs/rfc-2627-raw-dylib/link-ordinal-not-foreign-fn.rs2
-rw-r--r--tests/ui/rust-2024/unsafe-attributes/unsafe-attributes-fix.fixed10
-rw-r--r--tests/ui/rust-2024/unsafe-attributes/unsafe-attributes-fix.rs10
-rw-r--r--tests/ui/self/arbitrary-self-from-method-substs-ice.rs2
-rw-r--r--tests/ui/self/arbitrary-self-from-method-substs-ice.stderr9
-rw-r--r--tests/ui/self/dispatch-from-dyn-zst-transmute-zst-nonzst.rs25
-rw-r--r--tests/ui/self/dispatch-from-dyn-zst-transmute-zst-nonzst.stderr16
-rw-r--r--tests/ui/self/dispatch-from-dyn-zst-transmute.rs34
-rw-r--r--tests/ui/self/dispatch-from-dyn-zst-transmute.stderr16
-rw-r--r--tests/ui/self/phantomdata-in-coerce-and-dispatch-impls.rs25
-rw-r--r--tests/ui/simd/type-generic-monomorphisation-extern-nonnull-ptr.rs2
-rw-r--r--tests/ui/stability-attribute/accidental-stable-in-unstable.rs1
-rw-r--r--tests/ui/stability-attribute/accidental-stable-in-unstable.stderr10
-rw-r--r--tests/ui/stability-attribute/allowed-through-unstable.rs1
-rw-r--r--tests/ui/stability-attribute/allowed-through-unstable.stderr12
-rw-r--r--tests/ui/stability-attribute/auxiliary/allowed-through-unstable-core.rs4
-rw-r--r--tests/ui/stability-attribute/missing-const-stability.rs1
-rw-r--r--tests/ui/stability-attribute/missing-const-stability.stderr14
-rw-r--r--tests/ui/statics/uninhabited-static.rs2
-rw-r--r--tests/ui/target-feature/invalid-attribute.rs4
-rw-r--r--tests/ui/target-feature/invalid-attribute.stderr24
-rw-r--r--tests/ui/traits/const-traits/auxiliary/staged-api.rs1
-rw-r--r--tests/ui/traits/const-traits/call-const-trait-method-pass.rs2
-rw-r--r--tests/ui/traits/const-traits/const-and-non-const-impl.rs2
-rw-r--r--tests/ui/traits/const-traits/cross-crate.stocknc.stderr8
-rw-r--r--tests/ui/traits/const-traits/generic-bound.rs2
-rw-r--r--tests/ui/traits/const-traits/syntactical-unstable.rs34
-rw-r--r--tests/ui/traits/const-traits/syntactical-unstable.stderr67
-rw-r--r--tests/ui/traits/const-traits/trait-default-body-stability.rs1
-rw-r--r--tests/ui/traits/const-traits/trait-default-body-stability.stderr4
-rw-r--r--tests/ui/traits/next-solver/known-type-outlives-has-constraints.rs13
-rw-r--r--tests/ui/traits/trait-upcasting/impossible-method-modulo-binders-2.rs39
-rw-r--r--tests/ui/traits/trait-upcasting/impossible-method-modulo-binders.rs40
-rw-r--r--tests/ui/traits/trait-upcasting/prefer-lower-candidates.rs29
-rw-r--r--tests/ui/unpretty/expanded-exhaustive.rs8
-rw-r--r--tests/ui/unpretty/expanded-exhaustive.stdout8
126 files changed, 1203 insertions, 263 deletions
diff --git a/tests/codegen-units/item-collection/closures.rs b/tests/codegen-units/item-collection/closures.rs
index 5fc80230925..864f98817a8 100644
--- a/tests/codegen-units/item-collection/closures.rs
+++ b/tests/codegen-units/item-collection/closures.rs
@@ -10,3 +10,9 @@ pub async fn async_fn() {}
 pub fn closure() {
     let _ = || {};
 }
+
+//~ MONO_ITEM fn A::{constant#0}::{closure#0} @@
+trait A where
+    [(); (|| {}, 1).1]: Sized,
+{
+}
diff --git a/tests/codegen-units/item-collection/drop-glue-eager.rs b/tests/codegen-units/item-collection/drop-glue-eager.rs
new file mode 100644
index 00000000000..c81074de490
--- /dev/null
+++ b/tests/codegen-units/item-collection/drop-glue-eager.rs
@@ -0,0 +1,56 @@
+// Ensure that we *eagerly* monomorphize drop instances for structs with lifetimes.
+
+//@ compile-flags:-Zprint-mono-items=eager
+//@ compile-flags:--crate-type=lib
+
+//~ MONO_ITEM fn std::ptr::drop_in_place::<StructWithDrop> - shim(Some(StructWithDrop))
+struct StructWithDrop {
+    x: i32,
+}
+
+impl Drop for StructWithDrop {
+    //~ MONO_ITEM fn <StructWithDrop as std::ops::Drop>::drop
+    fn drop(&mut self) {}
+}
+
+struct StructNoDrop {
+    x: i32,
+}
+
+//~ MONO_ITEM fn std::ptr::drop_in_place::<EnumWithDrop> - shim(Some(EnumWithDrop))
+enum EnumWithDrop {
+    A(i32),
+}
+
+impl Drop for EnumWithDrop {
+    //~ MONO_ITEM fn <EnumWithDrop as std::ops::Drop>::drop
+    fn drop(&mut self) {}
+}
+
+enum EnumNoDrop {
+    A(i32),
+}
+
+// We should be able to monomorphize drops for struct with lifetimes.
+impl<'a> Drop for StructWithDropAndLt<'a> {
+    //~ MONO_ITEM fn <StructWithDropAndLt<'_> as std::ops::Drop>::drop
+    fn drop(&mut self) {}
+}
+
+//~ MONO_ITEM fn std::ptr::drop_in_place::<StructWithDropAndLt<'_>> - shim(Some(StructWithDropAndLt<'_>))
+struct StructWithDropAndLt<'a> {
+    x: &'a i32,
+}
+
+// Make sure we don't ICE when checking impossible predicates for the struct.
+// Regression test for <https://github.com/rust-lang/rust/issues/135515>.
+//~ MONO_ITEM fn std::ptr::drop_in_place::<StructWithLtAndPredicate<'_>> - shim(Some(StructWithLtAndPredicate<'_>))
+struct StructWithLtAndPredicate<'a: 'a> {
+    x: &'a i32,
+}
+
+// We should be able to monomorphize drops for struct with lifetimes.
+impl<'a> Drop for StructWithLtAndPredicate<'a> {
+    //~ MONO_ITEM fn <StructWithLtAndPredicate<'_> as std::ops::Drop>::drop
+    fn drop(&mut self) {}
+}
diff --git a/tests/debuginfo/thread.rs b/tests/debuginfo/thread.rs
index dc8cb083219..0415f586f5d 100644
--- a/tests/debuginfo/thread.rs
+++ b/tests/debuginfo/thread.rs
@@ -12,15 +12,15 @@
 // cdb-check:join_handle,d    [Type: std::thread::JoinHandle<tuple$<> >]
 // cdb-check:    [...] __0              [Type: std::thread::JoinInner<tuple$<> >]
 //
-// cdb-command:dx -r3 t,d
+// cdb-command:dx t,d
 // cdb-check:t,d              : [...] [Type: std::thread::Thread *]
-// cdb-check:    [...] __0              : Other [Type: enum2$<std::thread::Inner>]
-// cdb-check:         [...] __0              [Type: core::pin::Pin<alloc::sync::Arc<std::thread::OtherInner,[...]> >]
+// cdb-check:[...] inner [...][Type: core::pin::Pin<alloc::sync::Arc<std::thread::Inner,alloc::alloc::Global> >]
 
 use std::thread;
 
 #[allow(unused_variables)]
-fn main() {
+fn main()
+{
     let join_handle = thread::spawn(|| {
         println!("Initialize a thread");
     });
diff --git a/tests/incremental/overlapping-impls-in-new-solver-issue-135514.rs b/tests/incremental/overlapping-impls-in-new-solver-issue-135514.rs
new file mode 100644
index 00000000000..8fcc913fa37
--- /dev/null
+++ b/tests/incremental/overlapping-impls-in-new-solver-issue-135514.rs
@@ -0,0 +1,40 @@
+// Regression test for #135514 where the new solver didn't properly record deps for incremental
+// compilation, similarly to `track-deps-in-new-solver.rs`.
+//
+// In this specially crafted example, @steffahn was able to trigger unsoundness with an overlapping
+// impl that was accepted during the incremental rebuild.
+
+//@ revisions: cpass1 cfail2
+//@ compile-flags: -Znext-solver
+
+pub trait Trait {}
+
+pub struct S0<T>(T);
+
+pub struct S<T>(T);
+impl<T> Trait for S<T> where S0<T>: Trait {}
+
+pub struct W;
+
+pub trait Other {
+    type Choose<L, R>;
+}
+
+// first impl
+impl<T: Trait> Other for T {
+    type Choose<L, R> = L;
+}
+
+// second impl
+impl<T> Other for S<T> {
+    //[cfail2]~^ ERROR conflicting implementations of trait
+    type Choose<L, R> = R;
+}
+
+#[cfg(cpass1)]
+impl Trait for W {}
+
+#[cfg(cfail2)]
+impl Trait for S<W> {}
+
+fn main() {}
diff --git a/tests/run-make/rustdoc-default-output/output-default.stdout b/tests/run-make/rustdoc-default-output/output-default.stdout
index c2d9309ba2e..c1b246e849c 100644
--- a/tests/run-make/rustdoc-default-output/output-default.stdout
+++ b/tests/run-make/rustdoc-default-output/output-default.stdout
@@ -194,7 +194,8 @@ Options:
         --doctest-compilation-args add arguments to be used when compiling doctests
                         
         --disable-minification 
-                        removed
+                        disable the minification of CSS/JS files
+                        (perma-unstable, do not use with cached files)
         --plugin-path DIR
                         removed, see issue #44136
                         <https://github.com/rust-lang/rust/issues/44136> for
diff --git a/tests/rustdoc-gui/links-color.goml b/tests/rustdoc-gui/links-color.goml
index ad1b5e801ca..8d26b826479 100644
--- a/tests/rustdoc-gui/links-color.goml
+++ b/tests/rustdoc-gui/links-color.goml
@@ -5,6 +5,7 @@ go-to: "file://" + |DOC_PATH| + "/test_docs/index.html"
 // This is needed so that the text color is computed.
 show-text: true
 
+// First we check the links of the different items.
 define-function: (
     "check-colors",
     [theme, mod, macro, struct, enum, trait, fn, type, union, keyword,
@@ -36,6 +37,11 @@ define-function: (
             },
             ALL,
         )
+        move-cursor-to: ".desc a[href='long_code_block_link/index.html']"
+        assert-css: (
+            ".desc a[href='long_code_block_link/index.html']",
+            {"text-decoration": "underline solid " + |mod|},
+        )
     },
 )
 
diff --git a/tests/rustdoc-js-std/return-based-sort.js b/tests/rustdoc-js-std/return-based-sort.js
new file mode 100644
index 00000000000..30baf1cd36e
--- /dev/null
+++ b/tests/rustdoc-js-std/return-based-sort.js
@@ -0,0 +1,30 @@
+// test that `clone`-like functions are sorted lower when
+// a search is based soley on return type
+
+const FILTER_CRATE = "core";
+
+const EXPECTED = [
+    {
+        'query': '-> AllocError',
+        'others': [
+            { 'path': 'core::alloc::Allocator', 'name': 'allocate' },
+            { 'path': 'core::alloc::AllocError', 'name': 'clone' },
+        ],
+    },
+    {
+        'query': 'AllocError',
+        'returned': [
+            { 'path': 'core::alloc::Allocator', 'name': 'allocate' },
+            { 'path': 'core::alloc::AllocError', 'name': 'clone' },
+         ],
+    },
+    {
+        'query': '-> &str',
+        'others': [
+            // type_name_of_val should not be consider clone-like
+            { 'path': 'core::any', 'name': 'type_name_of_val' },
+            // this returns `Option<&str>`, and thus should be sorted lower
+            { 'path': 'core::str::Split', 'name': 'next' },
+         ],
+    },
+]
diff --git a/tests/rustdoc-json/return_private.rs b/tests/rustdoc-json/return_private.rs
index 0b341e2bda7..c238a536e0d 100644
--- a/tests/rustdoc-json/return_private.rs
+++ b/tests/rustdoc-json/return_private.rs
@@ -6,7 +6,7 @@ mod secret {
 }
 
 //@ has "$.index[*][?(@.name=='get_secret')].inner.function"
-//@ is "$.index[*][?(@.name=='get_secret')].inner.function.sig.output.resolved_path.name" \"secret::Secret\"
+//@ is "$.index[*][?(@.name=='get_secret')].inner.function.sig.output.resolved_path.name" \"Secret\"
 pub fn get_secret() -> secret::Secret {
     secret::Secret
 }
diff --git a/tests/rustdoc/jump-to-def-pats.rs b/tests/rustdoc/jump-to-def-pats.rs
new file mode 100644
index 00000000000..147902b44cf
--- /dev/null
+++ b/tests/rustdoc/jump-to-def-pats.rs
@@ -0,0 +1,52 @@
+// This test ensures that patterns also get a link generated.
+
+//@ compile-flags: -Zunstable-options --generate-link-to-definition
+
+#![crate_name = "foo"]
+
+//@ has 'src/foo/jump-to-def-pats.rs.html'
+
+use std::fmt;
+
+pub enum MyEnum<T, E> {
+    Ok(T),
+    Err(E),
+    Some(T),
+    None,
+}
+
+pub enum X {
+    A,
+}
+
+pub fn foo() -> Result<(), ()> {
+    // FIXME: would be nice to be able to check both the class and the href at the same time so
+    // we could check the text as well...
+    //@ has - '//a[@class="prelude-val"]/@href' '{{channel}}/core/result/enum.Result.html#variant.Ok'
+    //@ has - '//a[@href="{{channel}}/core/result/enum.Result.html#variant.Ok"]' 'Ok'
+    Ok(())
+}
+
+impl<T, E> fmt::Display for MyEnum<T, E> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            //@ has - '//a[@href="#12"]' 'Self::Ok'
+            Self::Ok(_) => f.write_str("MyEnum::Ok"),
+            //@ has - '//a[@href="#13"]' 'MyEnum::Err'
+            MyEnum::Err(_) => f.write_str("MyEnum::Err"),
+            //@ has - '//a[@href="#14"]' 'Self::Some'
+            Self::Some(_) => f.write_str("MyEnum::Some"),
+            //@ has - '//a[@href="#15"]' 'Self::None'
+            Self::None => f.write_str("MyEnum::None"),
+        }
+    }
+}
+
+impl X {
+    fn p(&self) -> &str {
+        match self {
+            //@ has - '//a[@href="#19"]' 'Self::A'
+            Self::A => "X::A",
+        }
+    }
+}
diff --git a/tests/ui/associated-types/issue-91231.rs b/tests/ui/associated-types/issue-91231.rs
index d1c99fd44fa..a04ab60a7fc 100644
--- a/tests/ui/associated-types/issue-91231.rs
+++ b/tests/ui/associated-types/issue-91231.rs
@@ -3,7 +3,7 @@
 #![feature(extern_types)]
 #![allow(dead_code)]
 
-extern {
+extern "C" {
     type Extern;
 }
 
diff --git a/tests/ui/async-await/async-closures/fn-exception-target-features.stderr b/tests/ui/async-await/async-closures/fn-exception-target-features.stderr
index db5895108bb..37977b45250 100644
--- a/tests/ui/async-await/async-closures/fn-exception-target-features.stderr
+++ b/tests/ui/async-await/async-closures/fn-exception-target-features.stderr
@@ -1,11 +1,12 @@
-error[E0277]: the trait bound `fn() -> Pin<Box<(dyn Future<Output = ()> + 'static)>> {target_feature}: AsyncFn()` is not satisfied
+error[E0277]: the trait bound `#[target_features] fn() -> Pin<Box<(dyn Future<Output = ()> + 'static)>> {target_feature}: AsyncFn()` is not satisfied
   --> $DIR/fn-exception-target-features.rs:16:10
    |
 LL |     test(target_feature);
-   |     ---- ^^^^^^^^^^^^^^ the trait `AsyncFn()` is not implemented for fn item `fn() -> Pin<Box<(dyn Future<Output = ()> + 'static)>> {target_feature}`
+   |     ---- ^^^^^^^^^^^^^^ unsatisfied trait bound
    |     |
    |     required by a bound introduced by this call
    |
+   = help: the trait `AsyncFn()` is not implemented for fn item `#[target_features] fn() -> Pin<Box<(dyn Future<Output = ()> + 'static)>> {target_feature}`
 note: required by a bound in `test`
   --> $DIR/fn-exception-target-features.rs:13:17
    |
diff --git a/tests/ui/attributes/key-value-expansion.rs b/tests/ui/attributes/key-value-expansion.rs
index e5700a75935..9034e0a7398 100644
--- a/tests/ui/attributes/key-value-expansion.rs
+++ b/tests/ui/attributes/key-value-expansion.rs
@@ -39,7 +39,7 @@ bug!();
 macro_rules! doc_comment {
     ($x:expr) => {
         #[doc = $x]
-        extern {}
+        extern "C" {}
     };
 }
 
diff --git a/tests/ui/borrowck/issue-92157.rs b/tests/ui/borrowck/issue-92157.rs
index 3a6f8908b21..a2b685cdf6e 100644
--- a/tests/ui/borrowck/issue-92157.rs
+++ b/tests/ui/borrowck/issue-92157.rs
@@ -5,7 +5,7 @@
 
 #[cfg(target_os = "linux")]
 #[link(name = "c")]
-extern {}
+extern "C" {}
 
 #[lang = "start"]
 fn start<T>(_main: fn() -> T, _argc: isize, _argv: *const *const u8) -> isize {
diff --git a/tests/ui/closures/binder/nested-closures-regions.stderr b/tests/ui/closures/binder/nested-closures-regions.stderr
index a30339ac67b..909cbcaa808 100644
--- a/tests/ui/closures/binder/nested-closures-regions.stderr
+++ b/tests/ui/closures/binder/nested-closures-regions.stderr
@@ -9,7 +9,7 @@ LL |     for<'a> || -> () { for<'c> |_: &'a ()| -> () {}; };
                extern "rust-call" fn((&(),)),
                (),
            ]
-   = note: late-bound region is '?4
+   = note: late-bound region is '?3
    = note: late-bound region is '?2
    = note: number of external vids: 3
    = note: where '?1: '?2
@@ -26,7 +26,7 @@ LL |     for<'a> || -> () { for<'c> |_: &'a ()| -> () {}; };
                extern "rust-call" fn(()),
                (),
            ]
-   = note: late-bound region is '?2
+   = note: late-bound region is '?1
 
 note: no external requirements
   --> $DIR/nested-closures-regions.rs:7:1
diff --git a/tests/ui/coherence/coherence-negative-impls-copy.rs b/tests/ui/coherence/coherence-negative-impls-copy.rs
index 377d750f8ba..c0d852180a5 100644
--- a/tests/ui/coherence/coherence-negative-impls-copy.rs
+++ b/tests/ui/coherence/coherence-negative-impls-copy.rs
@@ -18,7 +18,7 @@ impl !Copy for WithDrop {}
 
 struct Type;
 trait Trait {}
-extern {
+extern "C" {
     type ExternType;
 }
 
diff --git a/tests/ui/conditional-compilation/cfg_accessible-not_sure.rs b/tests/ui/conditional-compilation/cfg_accessible-not_sure.rs
index e357d3c6cb5..2ac57f35674 100644
--- a/tests/ui/conditional-compilation/cfg_accessible-not_sure.rs
+++ b/tests/ui/conditional-compilation/cfg_accessible-not_sure.rs
@@ -63,7 +63,7 @@ const B: bool = true;
 
 // ForeignType::unresolved - error
 
-extern {
+extern "C" {
     type ForeignType;
 }
 
diff --git a/tests/ui/const-generics/type-mismatch-in-nested-goal.current.stderr b/tests/ui/const-generics/type-mismatch-in-nested-goal.current.stderr
new file mode 100644
index 00000000000..c6fb07926c8
--- /dev/null
+++ b/tests/ui/const-generics/type-mismatch-in-nested-goal.current.stderr
@@ -0,0 +1,45 @@
+error: the constant `N` is not of type `bool`
+  --> $DIR/type-mismatch-in-nested-goal.rs:9:50
+   |
+LL | fn needs_a<const N: usize>(_: [u8; N]) where (): A<N> {}
+   |                                                  ^^^^ expected `bool`, found `usize`
+   |
+note: required by a const generic parameter in `A`
+  --> $DIR/type-mismatch-in-nested-goal.rs:5:9
+   |
+LL | trait A<const B: bool> {}
+   |         ^^^^^^^^^^^^^ required by this const generic parameter in `A`
+
+error: the constant `true` is not of type `usize`
+  --> $DIR/type-mismatch-in-nested-goal.rs:13:13
+   |
+LL |     needs_a([]);
+   |     ------- ^^ expected `usize`, found `bool`
+   |     |
+   |     required by a bound introduced by this call
+   |
+note: required by a const generic parameter in `needs_a`
+  --> $DIR/type-mismatch-in-nested-goal.rs:9:12
+   |
+LL | fn needs_a<const N: usize>(_: [u8; N]) where (): A<N> {}
+   |            ^^^^^^^^^^^^^^ required by this const generic parameter in `needs_a`
+
+error[E0308]: mismatched types
+  --> $DIR/type-mismatch-in-nested-goal.rs:13:13
+   |
+LL |     needs_a([]);
+   |     ------- ^^ expected an array with a size of true, found one with a size of 0
+   |     |
+   |     arguments to this function are incorrect
+   |
+   = note: expected array `[u8; true]`
+              found array `[_; 0]`
+note: function defined here
+  --> $DIR/type-mismatch-in-nested-goal.rs:9:4
+   |
+LL | fn needs_a<const N: usize>(_: [u8; N]) where (): A<N> {}
+   |    ^^^^^^^                 ----------
+
+error: aborting due to 3 previous errors
+
+For more information about this error, try `rustc --explain E0308`.
diff --git a/tests/ui/const-generics/type-mismatch-in-nested-goal.next.stderr b/tests/ui/const-generics/type-mismatch-in-nested-goal.next.stderr
new file mode 100644
index 00000000000..c6fb07926c8
--- /dev/null
+++ b/tests/ui/const-generics/type-mismatch-in-nested-goal.next.stderr
@@ -0,0 +1,45 @@
+error: the constant `N` is not of type `bool`
+  --> $DIR/type-mismatch-in-nested-goal.rs:9:50
+   |
+LL | fn needs_a<const N: usize>(_: [u8; N]) where (): A<N> {}
+   |                                                  ^^^^ expected `bool`, found `usize`
+   |
+note: required by a const generic parameter in `A`
+  --> $DIR/type-mismatch-in-nested-goal.rs:5:9
+   |
+LL | trait A<const B: bool> {}
+   |         ^^^^^^^^^^^^^ required by this const generic parameter in `A`
+
+error: the constant `true` is not of type `usize`
+  --> $DIR/type-mismatch-in-nested-goal.rs:13:13
+   |
+LL |     needs_a([]);
+   |     ------- ^^ expected `usize`, found `bool`
+   |     |
+   |     required by a bound introduced by this call
+   |
+note: required by a const generic parameter in `needs_a`
+  --> $DIR/type-mismatch-in-nested-goal.rs:9:12
+   |
+LL | fn needs_a<const N: usize>(_: [u8; N]) where (): A<N> {}
+   |            ^^^^^^^^^^^^^^ required by this const generic parameter in `needs_a`
+
+error[E0308]: mismatched types
+  --> $DIR/type-mismatch-in-nested-goal.rs:13:13
+   |
+LL |     needs_a([]);
+   |     ------- ^^ expected an array with a size of true, found one with a size of 0
+   |     |
+   |     arguments to this function are incorrect
+   |
+   = note: expected array `[u8; true]`
+              found array `[_; 0]`
+note: function defined here
+  --> $DIR/type-mismatch-in-nested-goal.rs:9:4
+   |
+LL | fn needs_a<const N: usize>(_: [u8; N]) where (): A<N> {}
+   |    ^^^^^^^                 ----------
+
+error: aborting due to 3 previous errors
+
+For more information about this error, try `rustc --explain E0308`.
diff --git a/tests/ui/const-generics/type-mismatch-in-nested-goal.rs b/tests/ui/const-generics/type-mismatch-in-nested-goal.rs
new file mode 100644
index 00000000000..fd29019f89b
--- /dev/null
+++ b/tests/ui/const-generics/type-mismatch-in-nested-goal.rs
@@ -0,0 +1,17 @@
+//@ revisions: current next
+//@[next] compile-flags: -Znext-solver
+//@ ignore-compare-mode-next-solver (explicit revisions)
+
+trait A<const B: bool> {}
+
+impl A<true> for () {}
+
+fn needs_a<const N: usize>(_: [u8; N]) where (): A<N> {}
+//~^ ERROR the constant `N` is not of type `bool`
+
+pub fn main() {
+    needs_a([]);
+    //~^ ERROR the constant `true` is not of type `usize`
+    //~| ERROR mismatched types
+    // FIXME(const_generics): we should hide this error as we've already errored above
+}
diff --git a/tests/ui/consts/const-block-const-bound.rs b/tests/ui/consts/const-block-const-bound.rs
index 596aac09b31..b4b89a93e75 100644
--- a/tests/ui/consts/const-block-const-bound.rs
+++ b/tests/ui/consts/const-block-const-bound.rs
@@ -1,5 +1,3 @@
-//@ known-bug: #103507
-
 #![allow(unused)]
 #![feature(const_trait_impl, negative_impls, const_destruct)]
 
@@ -16,6 +14,6 @@ impl Drop for UnconstDrop {
 fn main() {
     const {
         f(UnconstDrop);
-        //FIXME ~^ ERROR can't drop
+        //~^ ERROR trait bound `UnconstDrop: const Destruct` is not satisfied
     }
 }
diff --git a/tests/ui/consts/const-block-const-bound.stderr b/tests/ui/consts/const-block-const-bound.stderr
index 0931eff2175..14c62fb4d25 100644
--- a/tests/ui/consts/const-block-const-bound.stderr
+++ b/tests/ui/consts/const-block-const-bound.stderr
@@ -1,5 +1,5 @@
 error[E0277]: the trait bound `UnconstDrop: const Destruct` is not satisfied
-  --> $DIR/const-block-const-bound.rs:18:11
+  --> $DIR/const-block-const-bound.rs:16:11
    |
 LL |         f(UnconstDrop);
    |         - ^^^^^^^^^^^
@@ -7,7 +7,7 @@ LL |         f(UnconstDrop);
    |         required by a bound introduced by this call
    |
 note: required by a bound in `f`
-  --> $DIR/const-block-const-bound.rs:8:15
+  --> $DIR/const-block-const-bound.rs:6:15
    |
 LL | const fn f<T: ~const Destruct>(x: T) {}
    |               ^^^^^^ required by this bound in `f`
diff --git a/tests/ui/consts/const-eval/validation-ice-extern-type-field.rs b/tests/ui/consts/const-eval/validation-ice-extern-type-field.rs
index 3502409d576..8a32b170c40 100644
--- a/tests/ui/consts/const-eval/validation-ice-extern-type-field.rs
+++ b/tests/ui/consts/const-eval/validation-ice-extern-type-field.rs
@@ -1,6 +1,6 @@
 #![feature(extern_types)]
 
-extern {
+extern "C" {
     type Opaque;
 }
 
diff --git a/tests/ui/consts/issue-94675.rs b/tests/ui/consts/issue-94675.rs
index 2e30eebb07b..e1c6861c510 100644
--- a/tests/ui/consts/issue-94675.rs
+++ b/tests/ui/consts/issue-94675.rs
@@ -1,5 +1,3 @@
-//@ known-bug: #103507
-
 #![feature(const_trait_impl, const_vec_string_slice)]
 
 struct Foo<'a> {
@@ -9,9 +7,7 @@ struct Foo<'a> {
 impl<'a> Foo<'a> {
     const fn spam(&mut self, baz: &mut Vec<u32>) {
         self.bar[0] = baz.len();
-        //FIXME ~^ ERROR: cannot call
-        //FIXME ~| ERROR: cannot call
-        //FIXME ~| ERROR: the trait bound
+        //~^ ERROR: cannot call
     }
 }
 
diff --git a/tests/ui/consts/issue-94675.stderr b/tests/ui/consts/issue-94675.stderr
index 8cad13724f2..63a86b45633 100644
--- a/tests/ui/consts/issue-94675.stderr
+++ b/tests/ui/consts/issue-94675.stderr
@@ -1,5 +1,5 @@
 error[E0015]: cannot call non-const operator in constant functions
-  --> $DIR/issue-94675.rs:11:17
+  --> $DIR/issue-94675.rs:9:17
    |
 LL |         self.bar[0] = baz.len();
    |                 ^^^
diff --git a/tests/ui/consts/promoted-const-drop.rs b/tests/ui/consts/promoted-const-drop.rs
index e09c30ea785..1d1897e15d4 100644
--- a/tests/ui/consts/promoted-const-drop.rs
+++ b/tests/ui/consts/promoted-const-drop.rs
@@ -1,4 +1,4 @@
-#![feature(const_trait_impl)]
+#![feature(const_trait_impl, const_destruct)]
 
 struct A();
 
diff --git a/tests/ui/consts/promoted_const_call.rs b/tests/ui/consts/promoted_const_call.rs
index c3920ff7241..79cb2ea2a02 100644
--- a/tests/ui/consts/promoted_const_call.rs
+++ b/tests/ui/consts/promoted_const_call.rs
@@ -1,6 +1,4 @@
-//@ known-bug: #103507
-
-#![feature(const_trait_impl)]
+#![feature(const_trait_impl, const_destruct)]
 
 struct Panic;
 impl const Drop for Panic { fn drop(&mut self) { panic!(); } }
@@ -8,15 +6,15 @@ impl const Drop for Panic { fn drop(&mut self) { panic!(); } }
 pub const fn id<T>(x: T) -> T { x }
 pub const C: () = {
     let _: &'static _ = &id(&Panic);
-    //FIXME ~^ ERROR: temporary value dropped while borrowed
-    //FIXME ~| ERROR: temporary value dropped while borrowed
+    //~^ ERROR: temporary value dropped while borrowed
+    //~| ERROR: temporary value dropped while borrowed
 };
 
 fn main() {
     let _: &'static _ = &id(&Panic);
-    //FIXME ~^ ERROR: temporary value dropped while borrowed
-    //FIXME ~| ERROR: temporary value dropped while borrowed
+    //~^ ERROR: temporary value dropped while borrowed
+    //~| ERROR: temporary value dropped while borrowed
     let _: &'static _ = &&(Panic, 0).1;
-    //FIXME~^ ERROR: temporary value dropped while borrowed
-    //FIXME~| ERROR: temporary value dropped while borrowed
+    //~^ ERROR: temporary value dropped while borrowed
+    //~| ERROR: temporary value dropped while borrowed
 }
diff --git a/tests/ui/consts/promoted_const_call.stderr b/tests/ui/consts/promoted_const_call.stderr
index 40c6d083b06..7a9cdd68704 100644
--- a/tests/ui/consts/promoted_const_call.stderr
+++ b/tests/ui/consts/promoted_const_call.stderr
@@ -1,17 +1,25 @@
-error[E0493]: destructor of `Panic` cannot be evaluated at compile-time
-  --> $DIR/promoted_const_call.rs:10:30
+error[E0716]: temporary value dropped while borrowed
+  --> $DIR/promoted_const_call.rs:8:26
    |
 LL |     let _: &'static _ = &id(&Panic);
-   |                              ^^^^^ - value is dropped here
-   |                              |
-   |                              the destructor for this type cannot be evaluated in constants
+   |            ----------    ^^^^^^^^^^ creates a temporary value which is freed while still in use
+   |            |
+   |            type annotation requires that borrow lasts for `'static`
+...
+LL | };
+   | - temporary value is freed at the end of this statement
+
+error[E0716]: temporary value dropped while borrowed
+  --> $DIR/promoted_const_call.rs:8:30
    |
-   = note: see issue #133214 <https://github.com/rust-lang/rust/issues/133214> for more information
-   = help: add `#![feature(const_destruct)]` to the crate attributes to enable
-   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
+LL |     let _: &'static _ = &id(&Panic);
+   |            ----------        ^^^^^ - temporary value is freed at the end of this statement
+   |            |                 |
+   |            |                 creates a temporary value which is freed while still in use
+   |            type annotation requires that borrow lasts for `'static`
 
 error[E0716]: temporary value dropped while borrowed
-  --> $DIR/promoted_const_call.rs:16:26
+  --> $DIR/promoted_const_call.rs:14:26
    |
 LL |     let _: &'static _ = &id(&Panic);
    |            ----------    ^^^^^^^^^^ creates a temporary value which is freed while still in use
@@ -22,7 +30,7 @@ LL | }
    | - temporary value is freed at the end of this statement
 
 error[E0716]: temporary value dropped while borrowed
-  --> $DIR/promoted_const_call.rs:16:30
+  --> $DIR/promoted_const_call.rs:14:30
    |
 LL |     let _: &'static _ = &id(&Panic);
    |            ----------        ^^^^^ - temporary value is freed at the end of this statement
@@ -31,7 +39,7 @@ LL |     let _: &'static _ = &id(&Panic);
    |            type annotation requires that borrow lasts for `'static`
 
 error[E0716]: temporary value dropped while borrowed
-  --> $DIR/promoted_const_call.rs:19:26
+  --> $DIR/promoted_const_call.rs:17:26
    |
 LL |     let _: &'static _ = &&(Panic, 0).1;
    |            ----------    ^^^^^^^^^^^^^ creates a temporary value which is freed while still in use
@@ -42,7 +50,7 @@ LL | }
    | - temporary value is freed at the end of this statement
 
 error[E0716]: temporary value dropped while borrowed
-  --> $DIR/promoted_const_call.rs:19:27
+  --> $DIR/promoted_const_call.rs:17:27
    |
 LL |     let _: &'static _ = &&(Panic, 0).1;
    |            ----------     ^^^^^^^^^^ creates a temporary value which is freed while still in use
@@ -52,7 +60,6 @@ LL |     let _: &'static _ = &&(Panic, 0).1;
 LL | }
    | - temporary value is freed at the end of this statement
 
-error: aborting due to 5 previous errors
+error: aborting due to 6 previous errors
 
-Some errors have detailed explanations: E0493, E0716.
-For more information about an error, try `rustc --explain E0493`.
+For more information about this error, try `rustc --explain E0716`.
diff --git a/tests/ui/delegation/glob-non-impl.rs b/tests/ui/delegation/glob-non-impl.rs
index d523731eeb3..e3a4061fb15 100644
--- a/tests/ui/delegation/glob-non-impl.rs
+++ b/tests/ui/delegation/glob-non-impl.rs
@@ -11,7 +11,7 @@ trait OtherTrait {
     reuse Trait::*; //~ ERROR glob delegation is only supported in impls
 }
 
-extern {
+extern "C" {
     reuse Trait::*; //~ ERROR delegation is not supported in `extern` blocks
 }
 
diff --git a/tests/ui/enum-discriminant/eval-error.rs b/tests/ui/enum-discriminant/eval-error.rs
new file mode 100644
index 00000000000..f2c3b581627
--- /dev/null
+++ b/tests/ui/enum-discriminant/eval-error.rs
@@ -0,0 +1,37 @@
+union Foo {
+    a: str,
+    //~^ ERROR the size for values of type `str` cannot be known at compilation time
+    //~| ERROR field must implement `Copy` or be wrapped in `ManuallyDrop<...>`
+}
+
+enum Bar {
+    Boo = {
+        let _: Option<Foo> = None;
+        0
+    },
+}
+
+union Foo2 {}
+//~^ ERROR unions cannot have zero fields
+
+enum Bar2 {
+    Boo = {
+        let _: Option<Foo2> = None;
+        0
+    },
+}
+
+#[repr(u8, packed)]
+//~^ ERROR attribute should be applied to a struct or union
+enum Foo3 {
+    A
+}
+
+enum Bar3 {
+    Boo = {
+        let _: Option<Foo3> = None;
+        0
+    },
+}
+
+fn main() {}
diff --git a/tests/ui/enum-discriminant/eval-error.stderr b/tests/ui/enum-discriminant/eval-error.stderr
new file mode 100644
index 00000000000..0f12308de3c
--- /dev/null
+++ b/tests/ui/enum-discriminant/eval-error.stderr
@@ -0,0 +1,51 @@
+error: unions cannot have zero fields
+  --> $DIR/eval-error.rs:14:1
+   |
+LL | union Foo2 {}
+   | ^^^^^^^^^^^^^
+
+error[E0517]: attribute should be applied to a struct or union
+  --> $DIR/eval-error.rs:24:12
+   |
+LL |   #[repr(u8, packed)]
+   |              ^^^^^^
+LL |
+LL | / enum Foo3 {
+LL | |     A
+LL | | }
+   | |_- not a struct or union
+
+error[E0277]: the size for values of type `str` cannot be known at compilation time
+  --> $DIR/eval-error.rs:2:8
+   |
+LL |     a: str,
+   |        ^^^ doesn't have a size known at compile-time
+   |
+   = help: the trait `Sized` is not implemented for `str`
+   = note: no field of a union may have a dynamically sized type
+   = help: change the field's type to have a statically known size
+help: borrowed types always have a statically known size
+   |
+LL |     a: &str,
+   |        +
+help: the `Box` type always has a statically known size and allocates its contents in the heap
+   |
+LL |     a: Box<str>,
+   |        ++++   +
+
+error[E0740]: field must implement `Copy` or be wrapped in `ManuallyDrop<...>` to be used in a union
+  --> $DIR/eval-error.rs:2:5
+   |
+LL |     a: str,
+   |     ^^^^^^
+   |
+   = note: union fields must not have drop side-effects, which is currently enforced via either `Copy` or `ManuallyDrop<...>`
+help: wrap the field type in `ManuallyDrop<...>`
+   |
+LL |     a: std::mem::ManuallyDrop<str>,
+   |        +++++++++++++++++++++++   +
+
+error: aborting due to 4 previous errors
+
+Some errors have detailed explanations: E0277, E0517, E0740.
+For more information about an error, try `rustc --explain E0277`.
diff --git a/tests/ui/extern/extern-type-diag-not-similar.rs b/tests/ui/extern/extern-type-diag-not-similar.rs
index 39d00a6c1bc..cd3eec9f1f7 100644
--- a/tests/ui/extern/extern-type-diag-not-similar.rs
+++ b/tests/ui/extern/extern-type-diag-not-similar.rs
@@ -4,11 +4,11 @@
 // because they are both extern types.
 
 #![feature(extern_types)]
-extern {
+extern "C" {
     type ShouldNotBeMentioned;
 }
 
-extern {
+extern "C" {
     type Foo;
 }
 
diff --git a/tests/ui/extern/issue-10025.rs b/tests/ui/extern/issue-10025.rs
index 140012f4a16..9be0f616fd2 100644
--- a/tests/ui/extern/issue-10025.rs
+++ b/tests/ui/extern/issue-10025.rs
@@ -1,5 +1,5 @@
 //@ run-pass
-#![allow(dead_code)]
+#![allow(dead_code, missing_abi)]
 
 unsafe extern fn foo() {}
 unsafe extern "C" fn bar() {}
diff --git a/tests/ui/extern/issue-95829.rs b/tests/ui/extern/issue-95829.rs
index c5ae4c68265..493d53d2532 100644
--- a/tests/ui/extern/issue-95829.rs
+++ b/tests/ui/extern/issue-95829.rs
@@ -1,6 +1,6 @@
 //@ edition:2018
 
-extern {
+extern "C" {
     async fn L() { //~ ERROR: incorrect function inside `extern` block
         //~^ ERROR: functions in `extern` blocks cannot have `async` qualifier
         async fn M() {}
diff --git a/tests/ui/extern/issue-95829.stderr b/tests/ui/extern/issue-95829.stderr
index 2f396b8cc04..2acd0fa3a26 100644
--- a/tests/ui/extern/issue-95829.stderr
+++ b/tests/ui/extern/issue-95829.stderr
@@ -1,8 +1,8 @@
 error: incorrect function inside `extern` block
   --> $DIR/issue-95829.rs:4:14
    |
-LL |   extern {
-   |   ------ `extern` blocks define existing foreign functions and functions inside of them cannot have a body
+LL |   extern "C" {
+   |   ---------- `extern` blocks define existing foreign functions and functions inside of them cannot have a body
 LL |       async fn L() {
    |  ______________^___-
    | |              |
@@ -18,8 +18,8 @@ LL | |     }
 error: functions in `extern` blocks cannot have `async` qualifier
   --> $DIR/issue-95829.rs:4:5
    |
-LL | extern {
-   | ------ in this `extern` block
+LL | extern "C" {
+   | ---------- in this `extern` block
 LL |     async fn L() {
    |     ^^^^^ help: remove the `async` qualifier
 
diff --git a/tests/ui/extern/not-in-block.rs b/tests/ui/extern/not-in-block.rs
index d3bcafdef7b..c2161635090 100644
--- a/tests/ui/extern/not-in-block.rs
+++ b/tests/ui/extern/not-in-block.rs
@@ -1,4 +1,5 @@
 #![crate_type = "lib"]
+#![allow(missing_abi)]
 
 extern fn none_fn(x: bool) -> i32;
 //~^ ERROR free function without a body
diff --git a/tests/ui/extern/not-in-block.stderr b/tests/ui/extern/not-in-block.stderr
index 2544949ab17..f86c279a234 100644
--- a/tests/ui/extern/not-in-block.stderr
+++ b/tests/ui/extern/not-in-block.stderr
@@ -1,5 +1,5 @@
 error: free function without a body
-  --> $DIR/not-in-block.rs:3:1
+  --> $DIR/not-in-block.rs:4:1
    |
 LL | extern fn none_fn(x: bool) -> i32;
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -14,7 +14,7 @@ LL | extern { fn none_fn(x: bool) -> i32; }
    | ~~~~~~~~                             +
 
 error: free function without a body
-  --> $DIR/not-in-block.rs:5:1
+  --> $DIR/not-in-block.rs:6:1
    |
 LL | extern "C" fn c_fn(x: bool) -> i32;
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
diff --git a/tests/ui/foreign/issue-91370-foreign-fn-block-impl.rs b/tests/ui/foreign/issue-91370-foreign-fn-block-impl.rs
index 2ac3ca29355..e8634de86ea 100644
--- a/tests/ui/foreign/issue-91370-foreign-fn-block-impl.rs
+++ b/tests/ui/foreign/issue-91370-foreign-fn-block-impl.rs
@@ -1,6 +1,6 @@
 // Regression test for issue #91370.
 
-extern {
+extern "C" {
     //~^ `extern` blocks define existing foreign functions
     fn f() {
         //~^ incorrect function inside `extern` block
diff --git a/tests/ui/foreign/issue-91370-foreign-fn-block-impl.stderr b/tests/ui/foreign/issue-91370-foreign-fn-block-impl.stderr
index fea2ab61e92..155fdf9d09a 100644
--- a/tests/ui/foreign/issue-91370-foreign-fn-block-impl.stderr
+++ b/tests/ui/foreign/issue-91370-foreign-fn-block-impl.stderr
@@ -1,8 +1,8 @@
 error: incorrect function inside `extern` block
   --> $DIR/issue-91370-foreign-fn-block-impl.rs:5:8
    |
-LL |   extern {
-   |   ------ `extern` blocks define existing foreign functions and functions inside of them cannot have a body
+LL |   extern "C" {
+   |   ---------- `extern` blocks define existing foreign functions and functions inside of them cannot have a body
 LL |
 LL |       fn f() {
    |  ________^___-
diff --git a/tests/ui/impl-trait/normalize-tait-in-const.rs b/tests/ui/impl-trait/normalize-tait-in-const.rs
index 1fd543b72e7..a735ef76673 100644
--- a/tests/ui/impl-trait/normalize-tait-in-const.rs
+++ b/tests/ui/impl-trait/normalize-tait-in-const.rs
@@ -1,4 +1,5 @@
-//@ known-bug: #103507
+//! This is a regression test for <https://github.com/rust-lang/rust/issues/103507>.
+//@ known-bug: #110395
 
 #![feature(type_alias_impl_trait)]
 #![feature(const_trait_impl, const_destruct)]
diff --git a/tests/ui/impl-trait/normalize-tait-in-const.stderr b/tests/ui/impl-trait/normalize-tait-in-const.stderr
index f4e8a872cec..c6cd1b139c5 100644
--- a/tests/ui/impl-trait/normalize-tait-in-const.stderr
+++ b/tests/ui/impl-trait/normalize-tait-in-const.stderr
@@ -1,5 +1,5 @@
 error: `~const` can only be applied to `#[const_trait]` traits
-  --> $DIR/normalize-tait-in-const.rs:26:35
+  --> $DIR/normalize-tait-in-const.rs:27:35
    |
 LL | const fn with_positive<F: for<'a> ~const Fn(&'a Alias<'a>) + ~const Destruct>(fun: F) {
    |                                   ^^^^^^ can't be applied to `Fn`
@@ -8,7 +8,7 @@ note: `Fn` can't be used with `~const` because it isn't annotated with `#[const_
   --> $SRC_DIR/core/src/ops/function.rs:LL:COL
 
 error: `~const` can only be applied to `#[const_trait]` traits
-  --> $DIR/normalize-tait-in-const.rs:26:35
+  --> $DIR/normalize-tait-in-const.rs:27:35
    |
 LL | const fn with_positive<F: for<'a> ~const Fn(&'a Alias<'a>) + ~const Destruct>(fun: F) {
    |                                   ^^^^^^ can't be applied to `Fn`
@@ -18,7 +18,7 @@ note: `Fn` can't be used with `~const` because it isn't annotated with `#[const_
    = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 
 error[E0015]: cannot call non-const closure in constant functions
-  --> $DIR/normalize-tait-in-const.rs:27:5
+  --> $DIR/normalize-tait-in-const.rs:28:5
    |
 LL |     fun(filter_positive());
    |     ^^^^^^^^^^^^^^^^^^^^^^
diff --git a/tests/ui/invalid/invalid-rustc_legacy_const_generics-arguments.rs b/tests/ui/invalid/invalid-rustc_legacy_const_generics-arguments.rs
index 6eabd9b1015..73a0363904a 100644
--- a/tests/ui/invalid/invalid-rustc_legacy_const_generics-arguments.rs
+++ b/tests/ui/invalid/invalid-rustc_legacy_const_generics-arguments.rs
@@ -21,7 +21,7 @@ struct S;
 #[rustc_legacy_const_generics(0usize)] //~ ERROR suffixed literals are not allowed in attributes
 fn foo6<const X: usize>() {}
 
-extern {
+extern "C" {
     #[rustc_legacy_const_generics(1)] //~ ERROR attribute should be applied to a function
     fn foo7<const X: usize>(); //~ ERROR foreign items may not have const parameters
 }
diff --git a/tests/ui/invalid_dispatch_from_dyn_impls.stderr b/tests/ui/invalid_dispatch_from_dyn_impls.stderr
index 168ed37d0e6..02718334c73 100644
--- a/tests/ui/invalid_dispatch_from_dyn_impls.stderr
+++ b/tests/ui/invalid_dispatch_from_dyn_impls.stderr
@@ -1,4 +1,4 @@
-error[E0378]: the trait `DispatchFromDyn` may only be implemented for structs containing the field being coerced, ZST fields with 1 byte alignment, and nothing else
+error[E0378]: the trait `DispatchFromDyn` may only be implemented for structs containing the field being coerced, ZST fields with 1 byte alignment that don't mention type/const generics, and nothing else
   --> $DIR/invalid_dispatch_from_dyn_impls.rs:10:1
    |
 LL | / impl<T, U> DispatchFromDyn<WrapperWithExtraField<U>> for WrapperWithExtraField<T>
@@ -35,7 +35,7 @@ LL | | where
 LL | |     T: Unsize<U>,
    | |_________________^
 
-error[E0378]: the trait `DispatchFromDyn` may only be implemented for structs containing the field being coerced, ZST fields with 1 byte alignment, and nothing else
+error[E0378]: the trait `DispatchFromDyn` may only be implemented for structs containing the field being coerced, ZST fields with 1 byte alignment that don't mention type/const generics, and nothing else
   --> $DIR/invalid_dispatch_from_dyn_impls.rs:46:1
    |
 LL | / impl<T: ?Sized, U: ?Sized> DispatchFromDyn<OverAligned<U>> for OverAligned<T>
diff --git a/tests/ui/issues/issue-25901.rs b/tests/ui/issues/issue-25901.rs
index bfcee1ac503..0ca34da95f5 100644
--- a/tests/ui/issues/issue-25901.rs
+++ b/tests/ui/issues/issue-25901.rs
@@ -2,7 +2,7 @@ struct A;
 struct B;
 
 static S: &'static B = &A;
-//~^ ERROR cannot perform conditionally-const deref coercion
+//~^ ERROR cannot perform non-const deref coercion
 
 use std::ops::Deref;
 
diff --git a/tests/ui/issues/issue-25901.stderr b/tests/ui/issues/issue-25901.stderr
index a954f38af83..233b5bfee50 100644
--- a/tests/ui/issues/issue-25901.stderr
+++ b/tests/ui/issues/issue-25901.stderr
@@ -1,4 +1,4 @@
-error[E0658]: cannot perform conditionally-const deref coercion on `A` in statics
+error[E0015]: cannot perform non-const deref coercion on `A` in statics
   --> $DIR/issue-25901.rs:4:24
    |
 LL | static S: &'static B = &A;
@@ -10,11 +10,14 @@ note: deref defined here
    |
 LL |     type Target = B;
    |     ^^^^^^^^^^^
+note: impl defined here, but it is not `const`
+  --> $DIR/issue-25901.rs:9:1
+   |
+LL | impl Deref for A {
+   | ^^^^^^^^^^^^^^^^
    = note: calls in statics are limited to constant functions, tuple structs and tuple variants
-   = note: see issue #67792 <https://github.com/rust-lang/rust/issues/67792> for more information
-   = help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
-   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
+   = note: consider wrapping this expression in `std::sync::LazyLock::new(|| ...)`
 
 error: aborting due to 1 previous error
 
-For more information about this error, try `rustc --explain E0658`.
+For more information about this error, try `rustc --explain E0015`.
diff --git a/tests/ui/layout/base-layout-is-sized-ice-123078.rs b/tests/ui/layout/base-layout-is-sized-ice-123078.rs
index b1c33e15075..15f11145f84 100644
--- a/tests/ui/layout/base-layout-is-sized-ice-123078.rs
+++ b/tests/ui/layout/base-layout-is-sized-ice-123078.rs
@@ -8,7 +8,6 @@ struct S {
 }
 
 const C: S = unsafe { std::mem::transmute(()) };
-//~^ ERROR cannot transmute between types of different sizes, or dependently-sized types
 const _: [(); {
     C;
     0
diff --git a/tests/ui/layout/base-layout-is-sized-ice-123078.stderr b/tests/ui/layout/base-layout-is-sized-ice-123078.stderr
index 455bd2cbf8b..9181368533a 100644
--- a/tests/ui/layout/base-layout-is-sized-ice-123078.stderr
+++ b/tests/ui/layout/base-layout-is-sized-ice-123078.stderr
@@ -16,16 +16,6 @@ help: the `Box` type always has a statically known size and allocates its conten
 LL |     a: Box<[u8]>,
    |        ++++    +
 
-error[E0512]: cannot transmute between types of different sizes, or dependently-sized types
-  --> $DIR/base-layout-is-sized-ice-123078.rs:10:23
-   |
-LL | const C: S = unsafe { std::mem::transmute(()) };
-   |                       ^^^^^^^^^^^^^^^^^^^
-   |
-   = note: source type: `()` (0 bits)
-   = note: target type: `S` (size can vary because of [u8])
-
-error: aborting due to 2 previous errors
+error: aborting due to 1 previous error
 
-Some errors have detailed explanations: E0277, E0512.
-For more information about an error, try `rustc --explain E0277`.
+For more information about this error, try `rustc --explain E0277`.
diff --git a/tests/ui/layout/debug.stderr b/tests/ui/layout/debug.stderr
index 1fc55511384..319c0de26a9 100644
--- a/tests/ui/layout/debug.stderr
+++ b/tests/ui/layout/debug.stderr
@@ -590,7 +590,7 @@ LL | type Impossible = (str, str);
    = help: the trait `Sized` is not implemented for `str`
    = note: only the last element of a tuple may have a dynamically sized type
 
-error: the type `EmptyUnion` has an unknown layout
+error: the type has an unknown layout
   --> $DIR/debug.rs:83:1
    |
 LL | union EmptyUnion {}
diff --git a/tests/ui/link-native-libs/issue-109144.rs b/tests/ui/link-native-libs/issue-109144.rs
index 2f740e55389..6970a4989bb 100644
--- a/tests/ui/link-native-libs/issue-109144.rs
+++ b/tests/ui/link-native-libs/issue-109144.rs
@@ -1,4 +1,4 @@
 #![crate_type = "lib"]
 #[link(kind = "static", modifiers = "+whole-archive,+bundle")]
 //~^ ERROR `#[link]` attribute requires a `name = "string"` argument
-extern  {}
+extern "C" {}
diff --git a/tests/ui/link-native-libs/suggest-libname-only-1.stderr b/tests/ui/link-native-libs/suggest-libname-only-1.stderr
index e142835a9d6..aae8f7de966 100644
--- a/tests/ui/link-native-libs/suggest-libname-only-1.stderr
+++ b/tests/ui/link-native-libs/suggest-libname-only-1.stderr
@@ -1,6 +1,14 @@
+warning: extern declarations without an explicit ABI are deprecated
+  --> $DIR/suggest-libname-only-1.rs:7:1
+   |
+LL | extern { }
+   | ^^^^^^ help: explicitly specify the C ABI: `extern "C"`
+   |
+   = note: `#[warn(missing_abi)]` on by default
+
 error: could not find native static library `libfoo.a`, perhaps an -L flag is missing?
    |
    = help: only provide the library name `foo`, not the full filename
 
-error: aborting due to 1 previous error
+error: aborting due to 1 previous error; 1 warning emitted
 
diff --git a/tests/ui/link-native-libs/suggest-libname-only-2.stderr b/tests/ui/link-native-libs/suggest-libname-only-2.stderr
index 392d2f01f61..a2adaee3f97 100644
--- a/tests/ui/link-native-libs/suggest-libname-only-2.stderr
+++ b/tests/ui/link-native-libs/suggest-libname-only-2.stderr
@@ -1,6 +1,14 @@
+warning: extern declarations without an explicit ABI are deprecated
+  --> $DIR/suggest-libname-only-2.rs:7:1
+   |
+LL | extern { }
+   | ^^^^^^ help: explicitly specify the C ABI: `extern "C"`
+   |
+   = note: `#[warn(missing_abi)]` on by default
+
 error: could not find native static library `bar.lib`, perhaps an -L flag is missing?
    |
    = help: only provide the library name `bar`, not the full filename
 
-error: aborting due to 1 previous error
+error: aborting due to 1 previous error; 1 warning emitted
 
diff --git a/tests/ui/lint/function-item-references.rs b/tests/ui/lint/function-item-references.rs
index 918d72e28a9..4f2fc4de863 100644
--- a/tests/ui/lint/function-item-references.rs
+++ b/tests/ui/lint/function-item-references.rs
@@ -11,7 +11,7 @@ fn baz(x: u32, y: u32) -> u32 { x + y }
 unsafe fn unsafe_fn() { }
 extern "C" fn c_fn() { }
 unsafe extern "C" fn unsafe_c_fn() { }
-unsafe extern fn variadic(_x: u32, _args: ...) { }
+unsafe extern "C" fn variadic(_x: u32, _args: ...) { }
 fn take_generic_ref<'a, T>(_x: &'a T) { }
 fn take_generic_array<T, const N: usize>(_x: [T; N]) { }
 fn multiple_generic<T, U>(_x: T, _y: U) { }
diff --git a/tests/ui/lint/lint-ctypes.rs b/tests/ui/lint/lint-ctypes.rs
index dae07930aba..6dd9be10a48 100644
--- a/tests/ui/lint/lint-ctypes.rs
+++ b/tests/ui/lint/lint-ctypes.rs
@@ -72,7 +72,7 @@ extern "C" {
     pub fn transparent_fn(p: TransparentBadFn); //~ ERROR: uses type `Box<u32>`
     pub fn raw_array(arr: [u8; 8]); //~ ERROR: uses type `[u8; 8]`
 
-    pub fn no_niche_a(a: Option<UnsafeCell<extern fn()>>);
+    pub fn no_niche_a(a: Option<UnsafeCell<extern "C" fn()>>);
     //~^ ERROR: uses type `Option<UnsafeCell<extern "C" fn()>>`
     pub fn no_niche_b(b: Option<UnsafeCell<&i32>>);
     //~^ ERROR: uses type `Option<UnsafeCell<&i32>>`
diff --git a/tests/ui/lint/lint-ctypes.stderr b/tests/ui/lint/lint-ctypes.stderr
index 2c81c7b8e4b..8137ae868d3 100644
--- a/tests/ui/lint/lint-ctypes.stderr
+++ b/tests/ui/lint/lint-ctypes.stderr
@@ -227,8 +227,8 @@ LL |     pub fn raw_array(arr: [u8; 8]);
 error: `extern` block uses type `Option<UnsafeCell<extern "C" fn()>>`, which is not FFI-safe
   --> $DIR/lint-ctypes.rs:75:26
    |
-LL |     pub fn no_niche_a(a: Option<UnsafeCell<extern fn()>>);
-   |                          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ not FFI-safe
+LL |     pub fn no_niche_a(a: Option<UnsafeCell<extern "C" fn()>>);
+   |                          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ not FFI-safe
    |
    = help: consider adding a `#[repr(C)]`, `#[repr(transparent)]`, or integer `#[repr(...)]` attribute to this enum
    = note: enum has no representation hint
diff --git a/tests/ui/macros/issue-68060.rs b/tests/ui/macros/issue-68060.rs
index 1a826bd60e0..4eddb96848c 100644
--- a/tests/ui/macros/issue-68060.rs
+++ b/tests/ui/macros/issue-68060.rs
@@ -3,8 +3,6 @@ fn main() {
         .map(
             #[target_feature(enable = "")]
             //~^ ERROR: attribute should be applied to a function
-            //~| ERROR: feature named `` is not valid
-            //~| NOTE: `` is not valid for this target
             #[track_caller]
             //~^ ERROR: `#[track_caller]` on closures is currently unstable
             //~| NOTE: see issue #87417
diff --git a/tests/ui/macros/issue-68060.stderr b/tests/ui/macros/issue-68060.stderr
index 5724a9ea438..ef2246d5bd6 100644
--- a/tests/ui/macros/issue-68060.stderr
+++ b/tests/ui/macros/issue-68060.stderr
@@ -7,14 +7,8 @@ LL |             #[target_feature(enable = "")]
 LL |             |_| (),
    |             ------ not a function definition
 
-error: the feature named `` is not valid for this target
-  --> $DIR/issue-68060.rs:4:30
-   |
-LL |             #[target_feature(enable = "")]
-   |                              ^^^^^^^^^^^ `` is not valid for this target
-
 error[E0658]: `#[track_caller]` on closures is currently unstable
-  --> $DIR/issue-68060.rs:8:13
+  --> $DIR/issue-68060.rs:6:13
    |
 LL |             #[track_caller]
    |             ^^^^^^^^^^^^^^^
@@ -23,6 +17,6 @@ LL |             #[track_caller]
    = help: add `#![feature(closure_track_caller)]` to the crate attributes to enable
    = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
-error: aborting due to 3 previous errors
+error: aborting due to 2 previous errors
 
 For more information about this error, try `rustc --explain E0658`.
diff --git a/tests/ui/nll/closure-requirements/escape-argument-callee.stderr b/tests/ui/nll/closure-requirements/escape-argument-callee.stderr
index a7a59dccf22..a445534c8d8 100644
--- a/tests/ui/nll/closure-requirements/escape-argument-callee.stderr
+++ b/tests/ui/nll/closure-requirements/escape-argument-callee.stderr
@@ -17,7 +17,7 @@ LL |         let mut closure = expect_sig(|p, y| *p = y);
    |                                       -  -  ^^^^^^ assignment requires that `'1` must outlive `'2`
    |                                       |  |
    |                                       |  has type `&'1 i32`
-   |                                       has type `&'?2 mut &'2 i32`
+   |                                       has type `&'?1 mut &'2 i32`
 
 note: no external requirements
   --> $DIR/escape-argument-callee.rs:20:1
diff --git a/tests/ui/nll/closure-requirements/propagate-approximated-shorter-to-static-comparing-against-free.stderr b/tests/ui/nll/closure-requirements/propagate-approximated-shorter-to-static-comparing-against-free.stderr
index 0094d7a50d3..621c1ea083b 100644
--- a/tests/ui/nll/closure-requirements/propagate-approximated-shorter-to-static-comparing-against-free.stderr
+++ b/tests/ui/nll/closure-requirements/propagate-approximated-shorter-to-static-comparing-against-free.stderr
@@ -20,7 +20,7 @@ LL |     foo(cell, |cell_a, cell_x| {
 LL |         cell_a.set(cell_x.get()); // forces 'x: 'a, error in closure
    |         ^^^^^^^^^^^^^^^^^^^^^^^^ `cell_x` escapes the closure body here
    |
-   = note: requirement occurs because of the type `Cell<&'?8 u32>`, which makes the generic argument `&'?8 u32` invariant
+   = note: requirement occurs because of the type `Cell<&'?9 u32>`, which makes the generic argument `&'?9 u32` invariant
    = note: the struct `Cell<T>` is invariant over the parameter `T`
    = help: see <https://doc.rust-lang.org/nomicon/subtyping.html> for more information about variance
 
diff --git a/tests/ui/nll/closure-requirements/propagate-fail-to-approximate-longer-no-bounds.stderr b/tests/ui/nll/closure-requirements/propagate-fail-to-approximate-longer-no-bounds.stderr
index 4558ff50674..f48ed2823dd 100644
--- a/tests/ui/nll/closure-requirements/propagate-fail-to-approximate-longer-no-bounds.stderr
+++ b/tests/ui/nll/closure-requirements/propagate-fail-to-approximate-longer-no-bounds.stderr
@@ -16,9 +16,9 @@ error: lifetime may not live long enough
   --> $DIR/propagate-fail-to-approximate-longer-no-bounds.rs:37:9
    |
 LL |     establish_relationships(&cell_a, &cell_b, |_outlives, x, y| {
-   |                                                ---------  - has type `&'?7 Cell<&'1 u32>`
+   |                                                ---------  - has type `&'?6 Cell<&'1 u32>`
    |                                                |
-   |                                                has type `&'?5 Cell<&'2 &'?1 u32>`
+   |                                                has type `&'?4 Cell<&'2 &'?1 u32>`
 LL |         // Only works if 'x: 'y:
 LL |         demand_y(x, y, x.get())
    |         ^^^^^^^^^^^^^^^^^^^^^^^ argument requires that `'1` must outlive `'2`
diff --git a/tests/ui/nll/closure-requirements/propagate-fail-to-approximate-longer-wrong-bounds.stderr b/tests/ui/nll/closure-requirements/propagate-fail-to-approximate-longer-wrong-bounds.stderr
index 83173ae80c0..a090e94593f 100644
--- a/tests/ui/nll/closure-requirements/propagate-fail-to-approximate-longer-wrong-bounds.stderr
+++ b/tests/ui/nll/closure-requirements/propagate-fail-to-approximate-longer-wrong-bounds.stderr
@@ -16,9 +16,9 @@ error: lifetime may not live long enough
   --> $DIR/propagate-fail-to-approximate-longer-wrong-bounds.rs:41:9
    |
 LL |     establish_relationships(&cell_a, &cell_b, |_outlives1, _outlives2, x, y| {
-   |                                                ----------  ---------- has type `&'?8 Cell<&'2 &'?2 u32>`
+   |                                                ----------  ---------- has type `&'?7 Cell<&'2 &'?2 u32>`
    |                                                |
-   |                                                has type `&'?6 Cell<&'1 &'?1 u32>`
+   |                                                has type `&'?5 Cell<&'1 &'?1 u32>`
 LL |         // Only works if 'x: 'y:
 LL |         demand_y(x, y, x.get())
    |         ^^^^^^^^^^^^^^^^^^^^^^^ argument requires that `'1` must outlive `'2`
diff --git a/tests/ui/offset-of/offset-of-dst-field.rs b/tests/ui/offset-of/offset-of-dst-field.rs
index 5ae15f32357..2e0bdb151e1 100644
--- a/tests/ui/offset-of/offset-of-dst-field.rs
+++ b/tests/ui/offset-of/offset-of-dst-field.rs
@@ -16,7 +16,7 @@ struct Beta {
     z: dyn Trait,
 }
 
-extern {
+extern "C" {
     type Extern;
 }
 
diff --git a/tests/ui/parser/bad-fn-ptr-qualifier.fixed b/tests/ui/parser/bad-fn-ptr-qualifier.fixed
index 558a27cd456..e2a2f9486b7 100644
--- a/tests/ui/parser/bad-fn-ptr-qualifier.fixed
+++ b/tests/ui/parser/bad-fn-ptr-qualifier.fixed
@@ -4,9 +4,9 @@
 
 pub type T0 =  fn(); //~ ERROR an `fn` pointer type cannot be `const`
 pub type T1 =  extern "C" fn(); //~ ERROR an `fn` pointer type cannot be `const`
-pub type T2 =  unsafe extern fn(); //~ ERROR an `fn` pointer type cannot be `const`
+pub type T2 =  unsafe extern "C" fn(); //~ ERROR an `fn` pointer type cannot be `const`
 pub type T3 =  fn(); //~ ERROR an `fn` pointer type cannot be `async`
-pub type T4 =  extern fn(); //~ ERROR an `fn` pointer type cannot be `async`
+pub type T4 =  extern "C" fn(); //~ ERROR an `fn` pointer type cannot be `async`
 pub type T5 =  unsafe extern "C" fn(); //~ ERROR an `fn` pointer type cannot be `async`
 pub type T6 =   unsafe extern "C" fn();
 //~^ ERROR an `fn` pointer type cannot be `const`
@@ -14,9 +14,9 @@ pub type T6 =   unsafe extern "C" fn();
 
 pub type FTT0 = for<'a>  fn(); //~ ERROR an `fn` pointer type cannot be `const`
 pub type FTT1 = for<'a>  extern "C" fn(); //~ ERROR an `fn` pointer type cannot be `const`
-pub type FTT2 = for<'a>  unsafe extern fn(); //~ ERROR an `fn` pointer type cannot be `const`
+pub type FTT2 = for<'a>  unsafe extern "C" fn(); //~ ERROR an `fn` pointer type cannot be `const`
 pub type FTT3 = for<'a>  fn(); //~ ERROR an `fn` pointer type cannot be `async`
-pub type FTT4 = for<'a>  extern fn(); //~ ERROR an `fn` pointer type cannot be `async`
+pub type FTT4 = for<'a>  extern "C" fn(); //~ ERROR an `fn` pointer type cannot be `async`
 pub type FTT5 = for<'a>  unsafe extern "C" fn();
 //~^ ERROR an `fn` pointer type cannot be `async`
 pub type FTT6 = for<'a>   unsafe extern "C" fn();
diff --git a/tests/ui/parser/bad-fn-ptr-qualifier.rs b/tests/ui/parser/bad-fn-ptr-qualifier.rs
index 9750f480935..f2611c93b17 100644
--- a/tests/ui/parser/bad-fn-ptr-qualifier.rs
+++ b/tests/ui/parser/bad-fn-ptr-qualifier.rs
@@ -4,9 +4,9 @@
 
 pub type T0 = const fn(); //~ ERROR an `fn` pointer type cannot be `const`
 pub type T1 = const extern "C" fn(); //~ ERROR an `fn` pointer type cannot be `const`
-pub type T2 = const unsafe extern fn(); //~ ERROR an `fn` pointer type cannot be `const`
+pub type T2 = const unsafe extern "C" fn(); //~ ERROR an `fn` pointer type cannot be `const`
 pub type T3 = async fn(); //~ ERROR an `fn` pointer type cannot be `async`
-pub type T4 = async extern fn(); //~ ERROR an `fn` pointer type cannot be `async`
+pub type T4 = async extern "C" fn(); //~ ERROR an `fn` pointer type cannot be `async`
 pub type T5 = async unsafe extern "C" fn(); //~ ERROR an `fn` pointer type cannot be `async`
 pub type T6 = const async unsafe extern "C" fn();
 //~^ ERROR an `fn` pointer type cannot be `const`
@@ -14,9 +14,9 @@ pub type T6 = const async unsafe extern "C" fn();
 
 pub type FTT0 = for<'a> const fn(); //~ ERROR an `fn` pointer type cannot be `const`
 pub type FTT1 = for<'a> const extern "C" fn(); //~ ERROR an `fn` pointer type cannot be `const`
-pub type FTT2 = for<'a> const unsafe extern fn(); //~ ERROR an `fn` pointer type cannot be `const`
+pub type FTT2 = for<'a> const unsafe extern "C" fn(); //~ ERROR an `fn` pointer type cannot be `const`
 pub type FTT3 = for<'a> async fn(); //~ ERROR an `fn` pointer type cannot be `async`
-pub type FTT4 = for<'a> async extern fn(); //~ ERROR an `fn` pointer type cannot be `async`
+pub type FTT4 = for<'a> async extern "C" fn(); //~ ERROR an `fn` pointer type cannot be `async`
 pub type FTT5 = for<'a> async unsafe extern "C" fn();
 //~^ ERROR an `fn` pointer type cannot be `async`
 pub type FTT6 = for<'a> const async unsafe extern "C" fn();
diff --git a/tests/ui/parser/bad-fn-ptr-qualifier.stderr b/tests/ui/parser/bad-fn-ptr-qualifier.stderr
index 523ee47b0c9..ddc8bac678c 100644
--- a/tests/ui/parser/bad-fn-ptr-qualifier.stderr
+++ b/tests/ui/parser/bad-fn-ptr-qualifier.stderr
@@ -29,15 +29,15 @@ LL + pub type T1 =  extern "C" fn();
 error: an `fn` pointer type cannot be `const`
   --> $DIR/bad-fn-ptr-qualifier.rs:7:15
    |
-LL | pub type T2 = const unsafe extern fn();
-   |               -----^^^^^^^^^^^^^^^^^^^
+LL | pub type T2 = const unsafe extern "C" fn();
+   |               -----^^^^^^^^^^^^^^^^^^^^^^^
    |               |
    |               `const` because of this
    |
 help: remove the `const` qualifier
    |
-LL - pub type T2 = const unsafe extern fn();
-LL + pub type T2 =  unsafe extern fn();
+LL - pub type T2 = const unsafe extern "C" fn();
+LL + pub type T2 =  unsafe extern "C" fn();
    |
 
 error: an `fn` pointer type cannot be `async`
@@ -57,15 +57,15 @@ LL + pub type T3 =  fn();
 error: an `fn` pointer type cannot be `async`
   --> $DIR/bad-fn-ptr-qualifier.rs:9:15
    |
-LL | pub type T4 = async extern fn();
-   |               -----^^^^^^^^^^^^
+LL | pub type T4 = async extern "C" fn();
+   |               -----^^^^^^^^^^^^^^^^
    |               |
    |               `async` because of this
    |
 help: remove the `async` qualifier
    |
-LL - pub type T4 = async extern fn();
-LL + pub type T4 =  extern fn();
+LL - pub type T4 = async extern "C" fn();
+LL + pub type T4 =  extern "C" fn();
    |
 
 error: an `fn` pointer type cannot be `async`
@@ -141,15 +141,15 @@ LL + pub type FTT1 = for<'a>  extern "C" fn();
 error: an `fn` pointer type cannot be `const`
   --> $DIR/bad-fn-ptr-qualifier.rs:17:17
    |
-LL | pub type FTT2 = for<'a> const unsafe extern fn();
-   |                 ^^^^^^^^-----^^^^^^^^^^^^^^^^^^^
+LL | pub type FTT2 = for<'a> const unsafe extern "C" fn();
+   |                 ^^^^^^^^-----^^^^^^^^^^^^^^^^^^^^^^^
    |                         |
    |                         `const` because of this
    |
 help: remove the `const` qualifier
    |
-LL - pub type FTT2 = for<'a> const unsafe extern fn();
-LL + pub type FTT2 = for<'a>  unsafe extern fn();
+LL - pub type FTT2 = for<'a> const unsafe extern "C" fn();
+LL + pub type FTT2 = for<'a>  unsafe extern "C" fn();
    |
 
 error: an `fn` pointer type cannot be `async`
@@ -169,15 +169,15 @@ LL + pub type FTT3 = for<'a>  fn();
 error: an `fn` pointer type cannot be `async`
   --> $DIR/bad-fn-ptr-qualifier.rs:19:17
    |
-LL | pub type FTT4 = for<'a> async extern fn();
-   |                 ^^^^^^^^-----^^^^^^^^^^^^
+LL | pub type FTT4 = for<'a> async extern "C" fn();
+   |                 ^^^^^^^^-----^^^^^^^^^^^^^^^^
    |                         |
    |                         `async` because of this
    |
 help: remove the `async` qualifier
    |
-LL - pub type FTT4 = for<'a> async extern fn();
-LL + pub type FTT4 = for<'a>  extern fn();
+LL - pub type FTT4 = for<'a> async extern "C" fn();
+LL + pub type FTT4 = for<'a>  extern "C" fn();
    |
 
 error: an `fn` pointer type cannot be `async`
diff --git a/tests/ui/parser/bad-lit-suffixes.rs b/tests/ui/parser/bad-lit-suffixes.rs
index c614f493885..f29dc53d322 100644
--- a/tests/ui/parser/bad-lit-suffixes.rs
+++ b/tests/ui/parser/bad-lit-suffixes.rs
@@ -1,10 +1,10 @@
 #![feature(rustc_attrs)]
 
-extern
+extern //~ WARN missing_abi
     "C"suffix //~ ERROR suffixes on string literals are invalid
     fn foo() {}
 
-extern
+extern //~ WARN missing_abi
     "C"suffix //~ ERROR suffixes on string literals are invalid
 {}
 
diff --git a/tests/ui/parser/bad-lit-suffixes.stderr b/tests/ui/parser/bad-lit-suffixes.stderr
index b5dacdf7d0d..121db2058f1 100644
--- a/tests/ui/parser/bad-lit-suffixes.stderr
+++ b/tests/ui/parser/bad-lit-suffixes.stderr
@@ -49,6 +49,20 @@ LL | #[rustc_layout_scalar_valid_range_start(0suffix)]
    |
    = help: the suffix must be one of the numeric types (`u32`, `isize`, `f32`, etc.)
 
+warning: extern declarations without an explicit ABI are deprecated
+  --> $DIR/bad-lit-suffixes.rs:3:1
+   |
+LL | extern
+   | ^^^^^^ help: explicitly specify the C ABI: `extern "C"`
+   |
+   = note: `#[warn(missing_abi)]` on by default
+
+warning: extern declarations without an explicit ABI are deprecated
+  --> $DIR/bad-lit-suffixes.rs:7:1
+   |
+LL | extern
+   | ^^^^^^ help: explicitly specify the C ABI: `extern "C"`
+
 error: suffixes on string literals are invalid
   --> $DIR/bad-lit-suffixes.rs:12:5
    |
@@ -149,5 +163,5 @@ LL |     1.0e10suffix;
    |
    = help: valid suffixes are `f32` and `f64`
 
-error: aborting due to 21 previous errors
+error: aborting due to 21 previous errors; 2 warnings emitted
 
diff --git a/tests/ui/parser/issues/issue-87217-keyword-order/wrong-unsafe.rs b/tests/ui/parser/issues/issue-87217-keyword-order/wrong-unsafe.rs
index 34b687a0f52..5ecf804de09 100644
--- a/tests/ui/parser/issues/issue-87217-keyword-order/wrong-unsafe.rs
+++ b/tests/ui/parser/issues/issue-87217-keyword-order/wrong-unsafe.rs
@@ -1,4 +1,5 @@
 //@ edition:2018
+#![allow(missing_abi)]
 
 // There is an order to respect for keywords before a function:
 // `<visibility>, const, async, unsafe, extern, "<ABI>"`
diff --git a/tests/ui/parser/issues/issue-87217-keyword-order/wrong-unsafe.stderr b/tests/ui/parser/issues/issue-87217-keyword-order/wrong-unsafe.stderr
index 0e9f7c51e1a..232da9acef3 100644
--- a/tests/ui/parser/issues/issue-87217-keyword-order/wrong-unsafe.stderr
+++ b/tests/ui/parser/issues/issue-87217-keyword-order/wrong-unsafe.stderr
@@ -1,5 +1,5 @@
 error: expected `fn`, found keyword `unsafe`
-  --> $DIR/wrong-unsafe.rs:9:8
+  --> $DIR/wrong-unsafe.rs:10:8
    |
 LL | extern unsafe fn test() {}
    | -------^^^^^^
diff --git a/tests/ui/parser/item-kw-case-mismatch.fixed b/tests/ui/parser/item-kw-case-mismatch.fixed
index f5afa482712..4ee8f9c19dc 100644
--- a/tests/ui/parser/item-kw-case-mismatch.fixed
+++ b/tests/ui/parser/item-kw-case-mismatch.fixed
@@ -25,7 +25,7 @@ const unsafe fn _e() {}
 //~| ERROR keyword `unsafe` is written in the wrong case
 //~| ERROR keyword `fn` is written in the wrong case
 
-unsafe extern fn _f() {}
+unsafe extern "C" fn _f() {}
 //~^ ERROR keyword `unsafe` is written in the wrong case
 //~| ERROR keyword `extern` is written in the wrong case
 
diff --git a/tests/ui/parser/item-kw-case-mismatch.rs b/tests/ui/parser/item-kw-case-mismatch.rs
index ea224e08a00..6c858b848cf 100644
--- a/tests/ui/parser/item-kw-case-mismatch.rs
+++ b/tests/ui/parser/item-kw-case-mismatch.rs
@@ -25,7 +25,7 @@ CONST UNSAFE FN _e() {}
 //~| ERROR keyword `unsafe` is written in the wrong case
 //~| ERROR keyword `fn` is written in the wrong case
 
-unSAFE EXTern fn _f() {}
+unSAFE EXTern "C" fn _f() {}
 //~^ ERROR keyword `unsafe` is written in the wrong case
 //~| ERROR keyword `extern` is written in the wrong case
 
diff --git a/tests/ui/parser/item-kw-case-mismatch.stderr b/tests/ui/parser/item-kw-case-mismatch.stderr
index 0abc59e064a..36df72b5cad 100644
--- a/tests/ui/parser/item-kw-case-mismatch.stderr
+++ b/tests/ui/parser/item-kw-case-mismatch.stderr
@@ -111,23 +111,23 @@ LL | CONST UNSAFE fn _e() {}
 error: keyword `unsafe` is written in the wrong case
   --> $DIR/item-kw-case-mismatch.rs:28:1
    |
-LL | unSAFE EXTern fn _f() {}
+LL | unSAFE EXTern "C" fn _f() {}
    | ^^^^^^
    |
 help: write it in the correct case
    |
-LL | unsafe EXTern fn _f() {}
+LL | unsafe EXTern "C" fn _f() {}
    | ~~~~~~
 
 error: keyword `extern` is written in the wrong case
   --> $DIR/item-kw-case-mismatch.rs:28:8
    |
-LL | unSAFE EXTern fn _f() {}
+LL | unSAFE EXTern "C" fn _f() {}
    |        ^^^^^^
    |
 help: write it in the correct case
    |
-LL | unSAFE extern fn _f() {}
+LL | unSAFE extern "C" fn _f() {}
    |        ~~~~~~
 
 error: keyword `extern` is written in the wrong case
diff --git a/tests/ui/parser/lit-err-in-macro.rs b/tests/ui/parser/lit-err-in-macro.rs
index cff8ee6b40c..ca117ac4a15 100644
--- a/tests/ui/parser/lit-err-in-macro.rs
+++ b/tests/ui/parser/lit-err-in-macro.rs
@@ -1,6 +1,6 @@
 macro_rules! f {
     ($abi:literal) => {
-        extern $abi fn f() {}
+        extern $abi fn f() {} //~ WARN missing_abi
     }
 }
 
diff --git a/tests/ui/parser/lit-err-in-macro.stderr b/tests/ui/parser/lit-err-in-macro.stderr
index 12e6d519060..fc2603d0b10 100644
--- a/tests/ui/parser/lit-err-in-macro.stderr
+++ b/tests/ui/parser/lit-err-in-macro.stderr
@@ -4,5 +4,17 @@ error: suffixes on string literals are invalid
 LL | f!("Foo"__);
    |    ^^^^^^^ invalid suffix `__`
 
-error: aborting due to 1 previous error
+warning: extern declarations without an explicit ABI are deprecated
+  --> $DIR/lit-err-in-macro.rs:3:9
+   |
+LL |         extern $abi fn f() {}
+   |         ^^^^^^ help: explicitly specify the C ABI: `extern "C"`
+...
+LL | f!("Foo"__);
+   | ----------- in this macro invocation
+   |
+   = note: `#[warn(missing_abi)]` on by default
+   = note: this warning originates in the macro `f` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: aborting due to 1 previous error; 1 warning emitted
 
diff --git a/tests/ui/parser/recover/recover-const-async-fn-ptr.rs b/tests/ui/parser/recover/recover-const-async-fn-ptr.rs
index 2d8a3858aa6..45d75349599 100644
--- a/tests/ui/parser/recover/recover-const-async-fn-ptr.rs
+++ b/tests/ui/parser/recover/recover-const-async-fn-ptr.rs
@@ -2,9 +2,9 @@
 
 type T0 = const fn(); //~ ERROR an `fn` pointer type cannot be `const`
 type T1 = const extern "C" fn(); //~ ERROR an `fn` pointer type cannot be `const`
-type T2 = const unsafe extern fn(); //~ ERROR an `fn` pointer type cannot be `const`
+type T2 = const unsafe extern "C" fn(); //~ ERROR an `fn` pointer type cannot be `const`
 type T3 = async fn(); //~ ERROR an `fn` pointer type cannot be `async`
-type T4 = async extern fn(); //~ ERROR an `fn` pointer type cannot be `async`
+type T4 = async extern "C" fn(); //~ ERROR an `fn` pointer type cannot be `async`
 type T5 = async unsafe extern "C" fn(); //~ ERROR an `fn` pointer type cannot be `async`
 type T6 = const async unsafe extern "C" fn();
 //~^ ERROR an `fn` pointer type cannot be `const`
@@ -12,9 +12,9 @@ type T6 = const async unsafe extern "C" fn();
 
 type FT0 = for<'a> const fn(); //~ ERROR an `fn` pointer type cannot be `const`
 type FT1 = for<'a> const extern "C" fn(); //~ ERROR an `fn` pointer type cannot be `const`
-type FT2 = for<'a> const unsafe extern fn(); //~ ERROR an `fn` pointer type cannot be `const`
+type FT2 = for<'a> const unsafe extern "C" fn(); //~ ERROR an `fn` pointer type cannot be `const`
 type FT3 = for<'a> async fn(); //~ ERROR an `fn` pointer type cannot be `async`
-type FT4 = for<'a> async extern fn(); //~ ERROR an `fn` pointer type cannot be `async`
+type FT4 = for<'a> async extern "C" fn(); //~ ERROR an `fn` pointer type cannot be `async`
 type FT5 = for<'a> async unsafe extern "C" fn(); //~ ERROR an `fn` pointer type cannot be `async`
 type FT6 = for<'a> const async unsafe extern "C" fn();
 //~^ ERROR an `fn` pointer type cannot be `const`
diff --git a/tests/ui/parser/recover/recover-const-async-fn-ptr.stderr b/tests/ui/parser/recover/recover-const-async-fn-ptr.stderr
index 8e5b76163ad..9112a0e135a 100644
--- a/tests/ui/parser/recover/recover-const-async-fn-ptr.stderr
+++ b/tests/ui/parser/recover/recover-const-async-fn-ptr.stderr
@@ -29,15 +29,15 @@ LL + type T1 =  extern "C" fn();
 error: an `fn` pointer type cannot be `const`
   --> $DIR/recover-const-async-fn-ptr.rs:5:11
    |
-LL | type T2 = const unsafe extern fn();
-   |           -----^^^^^^^^^^^^^^^^^^^
+LL | type T2 = const unsafe extern "C" fn();
+   |           -----^^^^^^^^^^^^^^^^^^^^^^^
    |           |
    |           `const` because of this
    |
 help: remove the `const` qualifier
    |
-LL - type T2 = const unsafe extern fn();
-LL + type T2 =  unsafe extern fn();
+LL - type T2 = const unsafe extern "C" fn();
+LL + type T2 =  unsafe extern "C" fn();
    |
 
 error: an `fn` pointer type cannot be `async`
@@ -57,15 +57,15 @@ LL + type T3 =  fn();
 error: an `fn` pointer type cannot be `async`
   --> $DIR/recover-const-async-fn-ptr.rs:7:11
    |
-LL | type T4 = async extern fn();
-   |           -----^^^^^^^^^^^^
+LL | type T4 = async extern "C" fn();
+   |           -----^^^^^^^^^^^^^^^^
    |           |
    |           `async` because of this
    |
 help: remove the `async` qualifier
    |
-LL - type T4 = async extern fn();
-LL + type T4 =  extern fn();
+LL - type T4 = async extern "C" fn();
+LL + type T4 =  extern "C" fn();
    |
 
 error: an `fn` pointer type cannot be `async`
@@ -141,15 +141,15 @@ LL + type FT1 = for<'a>  extern "C" fn();
 error: an `fn` pointer type cannot be `const`
   --> $DIR/recover-const-async-fn-ptr.rs:15:12
    |
-LL | type FT2 = for<'a> const unsafe extern fn();
-   |            ^^^^^^^^-----^^^^^^^^^^^^^^^^^^^
+LL | type FT2 = for<'a> const unsafe extern "C" fn();
+   |            ^^^^^^^^-----^^^^^^^^^^^^^^^^^^^^^^^
    |                    |
    |                    `const` because of this
    |
 help: remove the `const` qualifier
    |
-LL - type FT2 = for<'a> const unsafe extern fn();
-LL + type FT2 = for<'a>  unsafe extern fn();
+LL - type FT2 = for<'a> const unsafe extern "C" fn();
+LL + type FT2 = for<'a>  unsafe extern "C" fn();
    |
 
 error: an `fn` pointer type cannot be `async`
@@ -169,15 +169,15 @@ LL + type FT3 = for<'a>  fn();
 error: an `fn` pointer type cannot be `async`
   --> $DIR/recover-const-async-fn-ptr.rs:17:12
    |
-LL | type FT4 = for<'a> async extern fn();
-   |            ^^^^^^^^-----^^^^^^^^^^^^
+LL | type FT4 = for<'a> async extern "C" fn();
+   |            ^^^^^^^^-----^^^^^^^^^^^^^^^^
    |                    |
    |                    `async` because of this
    |
 help: remove the `async` qualifier
    |
-LL - type FT4 = for<'a> async extern fn();
-LL + type FT4 = for<'a>  extern fn();
+LL - type FT4 = for<'a> async extern "C" fn();
+LL + type FT4 = for<'a>  extern "C" fn();
    |
 
 error: an `fn` pointer type cannot be `async`
diff --git a/tests/ui/parser/recover/recover-fn-ptr-with-generics.rs b/tests/ui/parser/recover/recover-fn-ptr-with-generics.rs
index 76c56a715d2..ab2cfc961df 100644
--- a/tests/ui/parser/recover/recover-fn-ptr-with-generics.rs
+++ b/tests/ui/parser/recover/recover-fn-ptr-with-generics.rs
@@ -19,7 +19,7 @@ fn main() {
     type Hmm = fn<>();
     //~^ ERROR function pointer types may not have generic parameters
 
-    let _: extern fn<'a: 'static>();
+    let _: extern "C" fn<'a: 'static>();
     //~^ ERROR function pointer types may not have generic parameters
     //~| ERROR bounds cannot be used in this context
 
diff --git a/tests/ui/parser/recover/recover-fn-ptr-with-generics.stderr b/tests/ui/parser/recover/recover-fn-ptr-with-generics.stderr
index 6b6cb2d6bdd..9023856ef24 100644
--- a/tests/ui/parser/recover/recover-fn-ptr-with-generics.stderr
+++ b/tests/ui/parser/recover/recover-fn-ptr-with-generics.stderr
@@ -59,15 +59,15 @@ LL |     type Hmm = fn<>();
    |                  ^^
 
 error: function pointer types may not have generic parameters
-  --> $DIR/recover-fn-ptr-with-generics.rs:22:21
+  --> $DIR/recover-fn-ptr-with-generics.rs:22:25
    |
-LL |     let _: extern fn<'a: 'static>();
-   |                     ^^^^^^^^^^^^^
+LL |     let _: extern "C" fn<'a: 'static>();
+   |                         ^^^^^^^^^^^^^
    |
 help: consider moving the lifetime parameter to a `for` parameter list
    |
-LL -     let _: extern fn<'a: 'static>();
-LL +     let _: for<'a> extern fn();
+LL -     let _: extern "C" fn<'a: 'static>();
+LL +     let _: for<'a> extern "C" fn();
    |
 
 error: function pointer types may not have generic parameters
@@ -101,10 +101,10 @@ LL |     type Identity = fn<T>(T) -> T;
    |                                 ^ not found in this scope
 
 error: bounds cannot be used in this context
-  --> $DIR/recover-fn-ptr-with-generics.rs:22:26
+  --> $DIR/recover-fn-ptr-with-generics.rs:22:30
    |
-LL |     let _: extern fn<'a: 'static>();
-   |                          ^^^^^^^
+LL |     let _: extern "C" fn<'a: 'static>();
+   |                              ^^^^^^^
 
 error: aborting due to 12 previous errors
 
diff --git a/tests/ui/parser/recover/recover-missing-semi-before-item.fixed b/tests/ui/parser/recover/recover-missing-semi-before-item.fixed
index 6f85452c6fb..871fa0d24ec 100644
--- a/tests/ui/parser/recover/recover-missing-semi-before-item.fixed
+++ b/tests/ui/parser/recover/recover-missing-semi-before-item.fixed
@@ -28,7 +28,7 @@ fn for_fn() {
 
 fn for_extern() {
     let foo = 3; //~ ERROR expected `;`, found keyword `extern`
-    extern fn foo() {}
+    extern "C" fn foo() {}
 }
 
 fn for_impl() {
diff --git a/tests/ui/parser/recover/recover-missing-semi-before-item.rs b/tests/ui/parser/recover/recover-missing-semi-before-item.rs
index f75945b55c2..de92603a74c 100644
--- a/tests/ui/parser/recover/recover-missing-semi-before-item.rs
+++ b/tests/ui/parser/recover/recover-missing-semi-before-item.rs
@@ -28,7 +28,7 @@ fn for_fn() {
 
 fn for_extern() {
     let foo = 3 //~ ERROR expected `;`, found keyword `extern`
-    extern fn foo() {}
+    extern "C" fn foo() {}
 }
 
 fn for_impl() {
diff --git a/tests/ui/parser/recover/recover-missing-semi-before-item.stderr b/tests/ui/parser/recover/recover-missing-semi-before-item.stderr
index 61c43f2f189..3b55cd9ddd0 100644
--- a/tests/ui/parser/recover/recover-missing-semi-before-item.stderr
+++ b/tests/ui/parser/recover/recover-missing-semi-before-item.stderr
@@ -35,7 +35,7 @@ error: expected `;`, found keyword `extern`
    |
 LL |     let foo = 3
    |                ^ help: add `;` here
-LL |     extern fn foo() {}
+LL |     extern "C" fn foo() {}
    |     ------ unexpected token
 
 error: expected `;`, found keyword `impl`
diff --git a/tests/ui/privacy/sysroot-private.default.stderr b/tests/ui/privacy/sysroot-private.default.stderr
new file mode 100644
index 00000000000..845d4558d13
--- /dev/null
+++ b/tests/ui/privacy/sysroot-private.default.stderr
@@ -0,0 +1,39 @@
+error[E0405]: cannot find trait `Equivalent` in this scope
+  --> $DIR/sysroot-private.rs:26:18
+   |
+LL | trait Trait2<K>: Equivalent<K> {}
+   |                  ^^^^^^^^^^ not found in this scope
+
+error[E0412]: cannot find type `K` in this scope
+  --> $DIR/sysroot-private.rs:31:35
+   |
+LL | fn trait_member<T>(val: &T, key: &K) -> bool {
+   |                 -                 ^
+   |                 |
+   |                 similarly named type parameter `T` defined here
+   |
+help: a type parameter with a similar name exists
+   |
+LL | fn trait_member<T>(val: &T, key: &T) -> bool {
+   |                                   ~
+help: you might be missing a type parameter
+   |
+LL | fn trait_member<T, K>(val: &T, key: &K) -> bool {
+   |                  +++
+
+error[E0220]: associated type `ExpressionStack` not found for `Trait`
+  --> $DIR/sysroot-private.rs:21:31
+   |
+LL | type AssociatedTy = dyn Trait<ExpressionStack = i32, Bar = i32>;
+   |                               ^^^^^^^^^^^^^^^ help: `Trait` has the following associated type: `Bar`
+
+error[E0425]: cannot find function `memchr2` in this scope
+  --> $DIR/sysroot-private.rs:39:5
+   |
+LL |     memchr2(b'a', b'b', buf)
+   |     ^^^^^^^ not found in this scope
+
+error: aborting due to 4 previous errors
+
+Some errors have detailed explanations: E0220, E0405, E0412, E0425.
+For more information about an error, try `rustc --explain E0220`.
diff --git a/tests/ui/privacy/sysroot-private.rs b/tests/ui/privacy/sysroot-private.rs
new file mode 100644
index 00000000000..67ab67c7f5c
--- /dev/null
+++ b/tests/ui/privacy/sysroot-private.rs
@@ -0,0 +1,42 @@
+//! Test that private dependencies of `std` that live in the sysroot do not reach through to
+//! diagnostics.
+//!
+//! This test would be more robust if we could patch the sysroot with an "evil" crate that
+//! provided known types that we control; however, this would effectively require rebuilding
+//! `std` (or patching crate metadata). So, this test relies on what is currently public API
+//! of `std`'s dependencies, but may not be robust against dependency upgrades/changes.
+
+//@ only-unix Windows sysroots seem to not expose this dependency
+//@ revisions: default rustc_private_enabled
+
+// Enabling `rustc_private` should `std`'s dependencies accessible, so they should show up
+// in diagnostics. NB: not all diagnostics are affected by this.
+#![cfg_attr(rustc_private_enabled, feature(rustc_private))]
+#![crate_type = "lib"]
+
+trait Trait { type Bar; }
+
+// Attempt to get a suggestion for `gimli::read::op::EvaluationStoreage`, which should not be
+// present in diagnostics (it is a dependency of the compiler).
+type AssociatedTy = dyn Trait<ExpressionStack = i32, Bar = i32>;
+//~^ ERROR associated type `ExpressionStack` not found
+//[rustc_private_enabled]~| NOTE there is an associated type `ExpressionStack` in the trait `gimli::read::op::EvaluationStorage`
+
+// Attempt to get a suggestion for `hashbrown::Equivalent`
+trait Trait2<K>: Equivalent<K> {}
+//~^ ERROR cannot find trait
+//~| NOTE not found
+
+// Attempt to get a suggestion for `hashbrown::Equivalent::equivalent`
+fn trait_member<T>(val: &T, key: &K) -> bool {
+    //~^ ERROR cannot find type `K`
+    //~| NOTE similarly named
+    val.equivalent(key)
+}
+
+// Attempt to get a suggestion for `memchr::memchr2`
+fn free_function(buf: &[u8]) -> Option<usize> {
+    memchr2(b'a', b'b', buf)
+    //~^ ERROR cannot find function
+    //~| NOTE not found
+}
diff --git a/tests/ui/privacy/sysroot-private.rustc_private_enabled.stderr b/tests/ui/privacy/sysroot-private.rustc_private_enabled.stderr
new file mode 100644
index 00000000000..98e6922428a
--- /dev/null
+++ b/tests/ui/privacy/sysroot-private.rustc_private_enabled.stderr
@@ -0,0 +1,39 @@
+error[E0405]: cannot find trait `Equivalent` in this scope
+  --> $DIR/sysroot-private.rs:26:18
+   |
+LL | trait Trait2<K>: Equivalent<K> {}
+   |                  ^^^^^^^^^^ not found in this scope
+
+error[E0412]: cannot find type `K` in this scope
+  --> $DIR/sysroot-private.rs:31:35
+   |
+LL | fn trait_member<T>(val: &T, key: &K) -> bool {
+   |                 -                 ^
+   |                 |
+   |                 similarly named type parameter `T` defined here
+   |
+help: a type parameter with a similar name exists
+   |
+LL | fn trait_member<T>(val: &T, key: &T) -> bool {
+   |                                   ~
+help: you might be missing a type parameter
+   |
+LL | fn trait_member<T, K>(val: &T, key: &K) -> bool {
+   |                  +++
+
+error[E0220]: associated type `ExpressionStack` not found for `Trait`
+  --> $DIR/sysroot-private.rs:21:31
+   |
+LL | type AssociatedTy = dyn Trait<ExpressionStack = i32, Bar = i32>;
+   |                               ^^^^^^^^^^^^^^^ there is an associated type `ExpressionStack` in the trait `gimli::read::op::EvaluationStorage`
+
+error[E0425]: cannot find function `memchr2` in this scope
+  --> $DIR/sysroot-private.rs:39:5
+   |
+LL |     memchr2(b'a', b'b', buf)
+   |     ^^^^^^^ not found in this scope
+
+error: aborting due to 4 previous errors
+
+Some errors have detailed explanations: E0220, E0405, E0412, E0425.
+For more information about an error, try `rustc --explain E0220`.
diff --git a/tests/ui/proc-macro/inner-attrs.stderr b/tests/ui/proc-macro/inner-attrs.stderr
index ee8732c650d..3ab180be821 100644
--- a/tests/ui/proc-macro/inner-attrs.stderr
+++ b/tests/ui/proc-macro/inner-attrs.stderr
@@ -22,5 +22,13 @@ error: expected non-macro inner attribute, found attribute macro `print_attr`
 LL |         #![print_attr]
    |            ^^^^^^^^^^ not a non-macro inner attribute
 
-error: aborting due to 4 previous errors
+warning: extern declarations without an explicit ABI are deprecated
+  --> $DIR/inner-attrs.rs:82:1
+   |
+LL | extern {
+   | ^^^^^^ help: explicitly specify the C ABI: `extern "C"`
+   |
+   = note: `#[warn(missing_abi)]` on by default
+
+error: aborting due to 4 previous errors; 1 warning emitted
 
diff --git a/tests/ui/proc-macro/issue-66286.rs b/tests/ui/proc-macro/issue-66286.rs
index 57d1af26e93..882f87fa4ac 100644
--- a/tests/ui/proc-macro/issue-66286.rs
+++ b/tests/ui/proc-macro/issue-66286.rs
@@ -5,7 +5,7 @@
 extern crate issue_66286;
 
 #[issue_66286::vec_ice]
-pub extern fn foo(_: Vec(u32)) -> u32 {
+pub extern "C" fn foo(_: Vec(u32)) -> u32 {
     //~^ ERROR: parenthesized type parameters may only be used with a `Fn` trait
     0
 }
diff --git a/tests/ui/proc-macro/issue-66286.stderr b/tests/ui/proc-macro/issue-66286.stderr
index fc4c2062fd7..c92bed1b563 100644
--- a/tests/ui/proc-macro/issue-66286.stderr
+++ b/tests/ui/proc-macro/issue-66286.stderr
@@ -1,13 +1,13 @@
 error[E0214]: parenthesized type parameters may only be used with a `Fn` trait
-  --> $DIR/issue-66286.rs:8:22
+  --> $DIR/issue-66286.rs:8:26
    |
-LL | pub extern fn foo(_: Vec(u32)) -> u32 {
-   |                      ^^^^^^^^ only `Fn` traits may use parentheses
+LL | pub extern "C" fn foo(_: Vec(u32)) -> u32 {
+   |                          ^^^^^^^^ only `Fn` traits may use parentheses
    |
 help: use angle brackets instead
    |
-LL | pub extern fn foo(_: Vec<u32>) -> u32 {
-   |                         ~   ~
+LL | pub extern "C" fn foo(_: Vec<u32>) -> u32 {
+   |                             ~   ~
 
 error: aborting due to 1 previous error
 
diff --git a/tests/ui/rfcs/rfc-2396-target_feature-11/fn-ptr.stderr b/tests/ui/rfcs/rfc-2396-target_feature-11/fn-ptr.stderr
index cc941be5479..a2bda229d10 100644
--- a/tests/ui/rfcs/rfc-2396-target_feature-11/fn-ptr.stderr
+++ b/tests/ui/rfcs/rfc-2396-target_feature-11/fn-ptr.stderr
@@ -10,13 +10,8 @@ LL |     let foo: fn() = foo;
    |              expected due to this
    |
    = note: expected fn pointer `fn()`
-                 found fn item `fn() {foo}`
-   = note: fn items are distinct from fn pointers
+                 found fn item `#[target_features] fn() {foo}`
    = note: functions with `#[target_feature]` can only be coerced to `unsafe` function pointers
-help: consider casting to a fn pointer
-   |
-LL |     let foo: fn() = foo as fn();
-   |                     ~~~~~~~~~~~
 
 error: aborting due to 1 previous error
 
diff --git a/tests/ui/rfcs/rfc-2396-target_feature-11/fn-traits.rs b/tests/ui/rfcs/rfc-2396-target_feature-11/fn-traits.rs
index 3c370a1b8f3..3eae79faf42 100644
--- a/tests/ui/rfcs/rfc-2396-target_feature-11/fn-traits.rs
+++ b/tests/ui/rfcs/rfc-2396-target_feature-11/fn-traits.rs
@@ -21,9 +21,9 @@ fn call_once(f: impl FnOnce()) {
 }
 
 fn main() {
-    call(foo); //~ ERROR expected a `Fn()` closure, found `fn() {foo}`
-    call_mut(foo); //~ ERROR expected a `FnMut()` closure, found `fn() {foo}`
-    call_once(foo); //~ ERROR expected a `FnOnce()` closure, found `fn() {foo}`
+    call(foo); //~ ERROR expected a `Fn()` closure, found `#[target_features] fn() {foo}`
+    call_mut(foo); //~ ERROR expected a `FnMut()` closure, found `#[target_features] fn() {foo}`
+    call_once(foo); //~ ERROR expected a `FnOnce()` closure, found `#[target_features] fn() {foo}`
 
     call(foo_unsafe);
     //~^ ERROR expected a `Fn()` closure, found `unsafe fn() {foo_unsafe}`
diff --git a/tests/ui/rfcs/rfc-2396-target_feature-11/fn-traits.stderr b/tests/ui/rfcs/rfc-2396-target_feature-11/fn-traits.stderr
index 4c07f4d6b99..2915b9ad1b3 100644
--- a/tests/ui/rfcs/rfc-2396-target_feature-11/fn-traits.stderr
+++ b/tests/ui/rfcs/rfc-2396-target_feature-11/fn-traits.stderr
@@ -1,13 +1,13 @@
-error[E0277]: expected a `Fn()` closure, found `fn() {foo}`
+error[E0277]: expected a `Fn()` closure, found `#[target_features] fn() {foo}`
   --> $DIR/fn-traits.rs:24:10
    |
 LL |     call(foo);
-   |     ---- ^^^ expected an `Fn()` closure, found `fn() {foo}`
+   |     ---- ^^^ expected an `Fn()` closure, found `#[target_features] fn() {foo}`
    |     |
    |     required by a bound introduced by this call
    |
-   = help: the trait `Fn()` is not implemented for fn item `fn() {foo}`
-   = note: wrap the `fn() {foo}` in a closure with no arguments: `|| { /* code */ }`
+   = help: the trait `Fn()` is not implemented for fn item `#[target_features] fn() {foo}`
+   = note: wrap the `#[target_features] fn() {foo}` in a closure with no arguments: `|| { /* code */ }`
    = note: `#[target_feature]` functions do not implement the `Fn` traits
 note: required by a bound in `call`
   --> $DIR/fn-traits.rs:11:17
@@ -15,16 +15,16 @@ note: required by a bound in `call`
 LL | fn call(f: impl Fn()) {
    |                 ^^^^ required by this bound in `call`
 
-error[E0277]: expected a `FnMut()` closure, found `fn() {foo}`
+error[E0277]: expected a `FnMut()` closure, found `#[target_features] fn() {foo}`
   --> $DIR/fn-traits.rs:25:14
    |
 LL |     call_mut(foo);
-   |     -------- ^^^ expected an `FnMut()` closure, found `fn() {foo}`
+   |     -------- ^^^ expected an `FnMut()` closure, found `#[target_features] fn() {foo}`
    |     |
    |     required by a bound introduced by this call
    |
-   = help: the trait `FnMut()` is not implemented for fn item `fn() {foo}`
-   = note: wrap the `fn() {foo}` in a closure with no arguments: `|| { /* code */ }`
+   = help: the trait `FnMut()` is not implemented for fn item `#[target_features] fn() {foo}`
+   = note: wrap the `#[target_features] fn() {foo}` in a closure with no arguments: `|| { /* code */ }`
    = note: `#[target_feature]` functions do not implement the `Fn` traits
 note: required by a bound in `call_mut`
   --> $DIR/fn-traits.rs:15:25
@@ -32,16 +32,16 @@ note: required by a bound in `call_mut`
 LL | fn call_mut(mut f: impl FnMut()) {
    |                         ^^^^^^^ required by this bound in `call_mut`
 
-error[E0277]: expected a `FnOnce()` closure, found `fn() {foo}`
+error[E0277]: expected a `FnOnce()` closure, found `#[target_features] fn() {foo}`
   --> $DIR/fn-traits.rs:26:15
    |
 LL |     call_once(foo);
-   |     --------- ^^^ expected an `FnOnce()` closure, found `fn() {foo}`
+   |     --------- ^^^ expected an `FnOnce()` closure, found `#[target_features] fn() {foo}`
    |     |
    |     required by a bound introduced by this call
    |
-   = help: the trait `FnOnce()` is not implemented for fn item `fn() {foo}`
-   = note: wrap the `fn() {foo}` in a closure with no arguments: `|| { /* code */ }`
+   = help: the trait `FnOnce()` is not implemented for fn item `#[target_features] fn() {foo}`
+   = note: wrap the `#[target_features] fn() {foo}` in a closure with no arguments: `|| { /* code */ }`
    = note: `#[target_feature]` functions do not implement the `Fn` traits
 note: required by a bound in `call_once`
   --> $DIR/fn-traits.rs:19:22
diff --git a/tests/ui/rfcs/rfc-2396-target_feature-11/trait-impl.rs b/tests/ui/rfcs/rfc-2396-target_feature-11/trait-impl.rs
index df575b0f6b6..a2ac6ff45fc 100644
--- a/tests/ui/rfcs/rfc-2396-target_feature-11/trait-impl.rs
+++ b/tests/ui/rfcs/rfc-2396-target_feature-11/trait-impl.rs
@@ -13,6 +13,7 @@ impl Foo for Bar {
     #[target_feature(enable = "sse2")]
     //~^ ERROR cannot be applied to safe trait method
     fn foo(&self) {}
+    //~^ ERROR method `foo` has an incompatible type for trait
 
     #[target_feature(enable = "sse2")]
     unsafe fn unsf_foo(&self) {}
diff --git a/tests/ui/rfcs/rfc-2396-target_feature-11/trait-impl.stderr b/tests/ui/rfcs/rfc-2396-target_feature-11/trait-impl.stderr
index 00efbb52f15..1ab1fad64cc 100644
--- a/tests/ui/rfcs/rfc-2396-target_feature-11/trait-impl.stderr
+++ b/tests/ui/rfcs/rfc-2396-target_feature-11/trait-impl.stderr
@@ -7,8 +7,22 @@ LL |
 LL |     fn foo(&self) {}
    |     ------------- not an `unsafe` function
 
+error[E0053]: method `foo` has an incompatible type for trait
+  --> $DIR/trait-impl.rs:15:5
+   |
+LL |     fn foo(&self) {}
+   |     ^^^^^^^^^^^^^ expected safe fn, found unsafe fn
+   |
+note: type in trait
+  --> $DIR/trait-impl.rs:6:5
+   |
+LL |     fn foo(&self);
+   |     ^^^^^^^^^^^^^^
+   = note: expected signature `fn(&Bar)`
+              found signature `#[target_features] fn(&Bar)`
+
 error: `#[target_feature(..)]` cannot be applied to safe trait method
-  --> $DIR/trait-impl.rs:22:5
+  --> $DIR/trait-impl.rs:23:5
    |
 LL |     #[target_feature(enable = "sse2")]
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot be applied to safe trait method
@@ -16,5 +30,6 @@ LL |
 LL |     fn foo(&self) {}
    |     ------------- not an `unsafe` function
 
-error: aborting due to 2 previous errors
+error: aborting due to 3 previous errors
 
+For more information about this error, try `rustc --explain E0053`.
diff --git a/tests/ui/rfcs/rfc-2627-raw-dylib/link-ordinal-not-foreign-fn.rs b/tests/ui/rfcs/rfc-2627-raw-dylib/link-ordinal-not-foreign-fn.rs
index f33a3d62e26..5982c771033 100644
--- a/tests/ui/rfcs/rfc-2627-raw-dylib/link-ordinal-not-foreign-fn.rs
+++ b/tests/ui/rfcs/rfc-2627-raw-dylib/link-ordinal-not-foreign-fn.rs
@@ -11,7 +11,7 @@ fn test() {}
 static mut imported_val: i32 = 123;
 
 #[link(name = "exporter", kind = "raw-dylib")]
-extern {
+extern "C" {
     #[link_ordinal(13)]
     fn imported_function();
 
diff --git a/tests/ui/rust-2024/unsafe-attributes/unsafe-attributes-fix.fixed b/tests/ui/rust-2024/unsafe-attributes/unsafe-attributes-fix.fixed
index 586881d1807..8b179f7ef93 100644
--- a/tests/ui/rust-2024/unsafe-attributes/unsafe-attributes-fix.fixed
+++ b/tests/ui/rust-2024/unsafe-attributes/unsafe-attributes-fix.fixed
@@ -4,7 +4,7 @@
 macro_rules! tt {
     ($e:tt) => {
         #$e
-        extern fn foo() {}
+        extern "C" fn foo() {}
     }
 }
 
@@ -13,7 +13,7 @@ macro_rules! ident {
         #[unsafe($e)]
         //~^ ERROR: unsafe attribute used without unsafe
         //~| WARN this is accepted in the current edition
-        extern fn bar() {}
+        extern "C" fn bar() {}
     }
 }
 
@@ -22,21 +22,21 @@ macro_rules! ident2 {
         #[unsafe($e = $l)]
         //~^ ERROR: unsafe attribute used without unsafe
         //~| WARN this is accepted in the current edition
-        extern fn bars() {}
+        extern "C" fn bars() {}
     }
 }
 
 macro_rules! meta {
     ($m:meta) => {
         #[$m]
-        extern fn baz() {}
+        extern "C" fn baz() {}
     }
 }
 
 macro_rules! meta2 {
     ($m:meta) => {
         #[$m]
-        extern fn baw() {}
+        extern "C" fn baw() {}
     }
 }
 
diff --git a/tests/ui/rust-2024/unsafe-attributes/unsafe-attributes-fix.rs b/tests/ui/rust-2024/unsafe-attributes/unsafe-attributes-fix.rs
index 03e122c7d57..34e5a6b96e3 100644
--- a/tests/ui/rust-2024/unsafe-attributes/unsafe-attributes-fix.rs
+++ b/tests/ui/rust-2024/unsafe-attributes/unsafe-attributes-fix.rs
@@ -4,7 +4,7 @@
 macro_rules! tt {
     ($e:tt) => {
         #$e
-        extern fn foo() {}
+        extern "C" fn foo() {}
     }
 }
 
@@ -13,7 +13,7 @@ macro_rules! ident {
         #[$e]
         //~^ ERROR: unsafe attribute used without unsafe
         //~| WARN this is accepted in the current edition
-        extern fn bar() {}
+        extern "C" fn bar() {}
     }
 }
 
@@ -22,21 +22,21 @@ macro_rules! ident2 {
         #[$e = $l]
         //~^ ERROR: unsafe attribute used without unsafe
         //~| WARN this is accepted in the current edition
-        extern fn bars() {}
+        extern "C" fn bars() {}
     }
 }
 
 macro_rules! meta {
     ($m:meta) => {
         #[$m]
-        extern fn baz() {}
+        extern "C" fn baz() {}
     }
 }
 
 macro_rules! meta2 {
     ($m:meta) => {
         #[$m]
-        extern fn baw() {}
+        extern "C" fn baw() {}
     }
 }
 
diff --git a/tests/ui/self/arbitrary-self-from-method-substs-ice.rs b/tests/ui/self/arbitrary-self-from-method-substs-ice.rs
index 2d6df816bb1..46e4afd8532 100644
--- a/tests/ui/self/arbitrary-self-from-method-substs-ice.rs
+++ b/tests/ui/self/arbitrary-self-from-method-substs-ice.rs
@@ -11,7 +11,7 @@ impl Foo {
         //~^ ERROR invalid generic `self` parameter type
         //~| ERROR destructor of `R` cannot be evaluated at compile-time
         self.0
-        //~^ ERROR cannot perform conditionally-const deref coercion on `R` in constant functions
+        //~^ ERROR cannot perform non-const deref coercion on `R` in constant functions
     }
 }
 
diff --git a/tests/ui/self/arbitrary-self-from-method-substs-ice.stderr b/tests/ui/self/arbitrary-self-from-method-substs-ice.stderr
index e6319d5a2c9..f217370b024 100644
--- a/tests/ui/self/arbitrary-self-from-method-substs-ice.stderr
+++ b/tests/ui/self/arbitrary-self-from-method-substs-ice.stderr
@@ -1,4 +1,4 @@
-error[E0658]: cannot perform conditionally-const deref coercion on `R` in constant functions
+error[E0015]: cannot perform non-const deref coercion on `R` in constant functions
   --> $DIR/arbitrary-self-from-method-substs-ice.rs:13:9
    |
 LL |         self.0
@@ -6,9 +6,6 @@ LL |         self.0
    |
    = note: attempting to deref into `Foo`
    = note: calls in constant functions are limited to constant functions, tuple structs and tuple variants
-   = note: see issue #67792 <https://github.com/rust-lang/rust/issues/67792> for more information
-   = help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
-   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
 error[E0493]: destructor of `R` cannot be evaluated at compile-time
   --> $DIR/arbitrary-self-from-method-substs-ice.rs:10:43
@@ -30,5 +27,5 @@ LL |     const fn get<R: Deref<Target = Self>>(self: R) -> u32 {
 
 error: aborting due to 3 previous errors
 
-Some errors have detailed explanations: E0493, E0658, E0801.
-For more information about an error, try `rustc --explain E0493`.
+Some errors have detailed explanations: E0015, E0493, E0801.
+For more information about an error, try `rustc --explain E0015`.
diff --git a/tests/ui/self/dispatch-from-dyn-zst-transmute-zst-nonzst.rs b/tests/ui/self/dispatch-from-dyn-zst-transmute-zst-nonzst.rs
new file mode 100644
index 00000000000..71f198f7dc7
--- /dev/null
+++ b/tests/ui/self/dispatch-from-dyn-zst-transmute-zst-nonzst.rs
@@ -0,0 +1,25 @@
+// We used to allow erroneous `DispatchFromDyn` impls whose RHS type contained
+// fields that weren't ZSTs. I don't believe this was possible to abuse, but
+// it's at least nice to give users better errors.
+
+#![feature(arbitrary_self_types)]
+#![feature(unsize)]
+#![feature(dispatch_from_dyn)]
+
+use std::marker::Unsize;
+use std::ops::DispatchFromDyn;
+
+struct Dispatchable<T: ?Sized, Z> {
+    _ptr: Box<T>,
+    z: Z,
+}
+
+impl<T, U> DispatchFromDyn<Dispatchable<U, i32>> for Dispatchable<T, ()>
+//~^ ERROR implementing the `DispatchFromDyn` trait requires multiple coercions
+where
+    T: Unsize<U> + ?Sized,
+    U: ?Sized,
+{
+}
+
+fn main() {}
diff --git a/tests/ui/self/dispatch-from-dyn-zst-transmute-zst-nonzst.stderr b/tests/ui/self/dispatch-from-dyn-zst-transmute-zst-nonzst.stderr
new file mode 100644
index 00000000000..1f13c51f679
--- /dev/null
+++ b/tests/ui/self/dispatch-from-dyn-zst-transmute-zst-nonzst.stderr
@@ -0,0 +1,16 @@
+error[E0378]: implementing the `DispatchFromDyn` trait requires multiple coercions
+  --> $DIR/dispatch-from-dyn-zst-transmute-zst-nonzst.rs:17:1
+   |
+LL | / impl<T, U> DispatchFromDyn<Dispatchable<U, i32>> for Dispatchable<T, ()>
+LL | |
+LL | | where
+LL | |     T: Unsize<U> + ?Sized,
+LL | |     U: ?Sized,
+   | |______________^
+   |
+   = note: the trait `DispatchFromDyn` may only be implemented for a coercion between structures with a single field being coerced
+   = note: currently, 2 fields need coercions: `_ptr` (`Box<T>` to `Box<U>`), `z` (`()` to `i32`)
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0378`.
diff --git a/tests/ui/self/dispatch-from-dyn-zst-transmute.rs b/tests/ui/self/dispatch-from-dyn-zst-transmute.rs
new file mode 100644
index 00000000000..57c255b4d7b
--- /dev/null
+++ b/tests/ui/self/dispatch-from-dyn-zst-transmute.rs
@@ -0,0 +1,34 @@
+#![feature(arbitrary_self_types)]
+#![feature(unsize)]
+#![feature(dispatch_from_dyn)]
+
+use std::marker::PhantomData;
+use std::marker::Unsize;
+use std::ops::DispatchFromDyn;
+use std::ops::Deref;
+
+struct IsSendToken<T: ?Sized>(PhantomData<fn(T) -> T>);
+
+struct Foo<'a, U: ?Sized> {
+    token: IsSendToken<U>,
+    ptr: &'a U,
+}
+
+impl<'a, T, U> DispatchFromDyn<Foo<'a, U>> for Foo<'a, T>
+//~^ ERROR implementing the `DispatchFromDyn` trait requires multiple coercions
+where
+    T: Unsize<U> + ?Sized,
+    U: ?Sized {}
+
+trait Bar {
+    fn f(self: Foo<'_, Self>);
+}
+
+impl<U: ?Sized> Deref for Foo<'_, U> {
+    type Target = U;
+    fn deref(&self) -> &U {
+        self.ptr
+    }
+}
+
+fn main() {}
diff --git a/tests/ui/self/dispatch-from-dyn-zst-transmute.stderr b/tests/ui/self/dispatch-from-dyn-zst-transmute.stderr
new file mode 100644
index 00000000000..5a8ae88b5f1
--- /dev/null
+++ b/tests/ui/self/dispatch-from-dyn-zst-transmute.stderr
@@ -0,0 +1,16 @@
+error[E0378]: implementing the `DispatchFromDyn` trait requires multiple coercions
+  --> $DIR/dispatch-from-dyn-zst-transmute.rs:17:1
+   |
+LL | / impl<'a, T, U> DispatchFromDyn<Foo<'a, U>> for Foo<'a, T>
+LL | |
+LL | | where
+LL | |     T: Unsize<U> + ?Sized,
+LL | |     U: ?Sized {}
+   | |_____________^
+   |
+   = note: the trait `DispatchFromDyn` may only be implemented for a coercion between structures with a single field being coerced
+   = note: currently, 2 fields need coercions: `token` (`IsSendToken<T>` to `IsSendToken<U>`), `ptr` (`&'a T` to `&'a U`)
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0378`.
diff --git a/tests/ui/self/phantomdata-in-coerce-and-dispatch-impls.rs b/tests/ui/self/phantomdata-in-coerce-and-dispatch-impls.rs
new file mode 100644
index 00000000000..9c7e33830f5
--- /dev/null
+++ b/tests/ui/self/phantomdata-in-coerce-and-dispatch-impls.rs
@@ -0,0 +1,25 @@
+//@ check-pass
+
+#![feature(coerce_unsized, dispatch_from_dyn, unsize)]
+
+use std::marker::Unsize;
+use std::ops::{CoerceUnsized, DispatchFromDyn};
+use std::marker::PhantomData;
+
+trait Mirror {
+    type Assoc;
+}
+impl<T> Mirror for T {
+    type Assoc = T;
+}
+
+struct W<T: 'static> {
+    t: &'static T,
+    f: <PhantomData<T> as Mirror>::Assoc,
+}
+
+impl<T, U> CoerceUnsized<W<U>> for W<T> where T: Unsize<U> {}
+
+impl<T, U> DispatchFromDyn<W<U>> for W<T> where T: Unsize<U> {}
+
+fn main() {}
diff --git a/tests/ui/simd/type-generic-monomorphisation-extern-nonnull-ptr.rs b/tests/ui/simd/type-generic-monomorphisation-extern-nonnull-ptr.rs
index a969295c9f9..65c57c42530 100644
--- a/tests/ui/simd/type-generic-monomorphisation-extern-nonnull-ptr.rs
+++ b/tests/ui/simd/type-generic-monomorphisation-extern-nonnull-ptr.rs
@@ -6,7 +6,7 @@
 
 use std::ptr::NonNull;
 
-extern {
+extern "C" {
     type Extern;
 }
 
diff --git a/tests/ui/stability-attribute/accidental-stable-in-unstable.rs b/tests/ui/stability-attribute/accidental-stable-in-unstable.rs
index 86a9d2066eb..a36a78ee442 100644
--- a/tests/ui/stability-attribute/accidental-stable-in-unstable.rs
+++ b/tests/ui/stability-attribute/accidental-stable-in-unstable.rs
@@ -8,3 +8,4 @@ use core::unicode::UNICODE_VERSION; //~ ERROR use of unstable library feature `u
 // Known accidental stabilizations with known users
 // fully stable @ core::mem::transmute
 use core::intrinsics::transmute; // depended upon by rand_core
+//~^WARN deprecated
diff --git a/tests/ui/stability-attribute/accidental-stable-in-unstable.stderr b/tests/ui/stability-attribute/accidental-stable-in-unstable.stderr
index 9943e6d7ac6..16e3676aa65 100644
--- a/tests/ui/stability-attribute/accidental-stable-in-unstable.stderr
+++ b/tests/ui/stability-attribute/accidental-stable-in-unstable.stderr
@@ -7,6 +7,14 @@ LL | use core::unicode::UNICODE_VERSION;
    = help: add `#![feature(unicode_internals)]` to the crate attributes to enable
    = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
-error: aborting due to 1 previous error
+warning: use of deprecated module `std::intrinsics`: import this function via `std::mem` instead
+  --> $DIR/accidental-stable-in-unstable.rs:10:23
+   |
+LL | use core::intrinsics::transmute; // depended upon by rand_core
+   |                       ^^^^^^^^^
+   |
+   = note: `#[warn(deprecated)]` on by default
+
+error: aborting due to 1 previous error; 1 warning emitted
 
 For more information about this error, try `rustc --explain E0658`.
diff --git a/tests/ui/stability-attribute/allowed-through-unstable.rs b/tests/ui/stability-attribute/allowed-through-unstable.rs
index 29911a70be9..e03417a4dae 100644
--- a/tests/ui/stability-attribute/allowed-through-unstable.rs
+++ b/tests/ui/stability-attribute/allowed-through-unstable.rs
@@ -6,4 +6,5 @@
 extern crate allowed_through_unstable_core;
 
 use allowed_through_unstable_core::unstable_module::OldStableTraitAllowedThoughUnstable;
+use allowed_through_unstable_core::unstable_module::OldStableTraitAllowedThoughUnstableWithDeprecation; //~WARN use of deprecated module `allowed_through_unstable_core::unstable_module`: use the new path instead
 use allowed_through_unstable_core::unstable_module::NewStableTraitNotAllowedThroughUnstable; //~ ERROR use of unstable library feature `unstable_test_feature`
diff --git a/tests/ui/stability-attribute/allowed-through-unstable.stderr b/tests/ui/stability-attribute/allowed-through-unstable.stderr
index 00eea9f730d..8d07b0cf9e8 100644
--- a/tests/ui/stability-attribute/allowed-through-unstable.stderr
+++ b/tests/ui/stability-attribute/allowed-through-unstable.stderr
@@ -1,5 +1,13 @@
+warning: use of deprecated module `allowed_through_unstable_core::unstable_module`: use the new path instead
+  --> $DIR/allowed-through-unstable.rs:9:53
+   |
+LL | use allowed_through_unstable_core::unstable_module::OldStableTraitAllowedThoughUnstableWithDeprecation;
+   |                                                     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: `#[warn(deprecated)]` on by default
+
 error[E0658]: use of unstable library feature `unstable_test_feature`
-  --> $DIR/allowed-through-unstable.rs:9:5
+  --> $DIR/allowed-through-unstable.rs:10:5
    |
 LL | use allowed_through_unstable_core::unstable_module::NewStableTraitNotAllowedThroughUnstable;
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -8,6 +16,6 @@ LL | use allowed_through_unstable_core::unstable_module::NewStableTraitNotAllowe
    = help: add `#![feature(unstable_test_feature)]` to the crate attributes to enable
    = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
-error: aborting due to 1 previous error
+error: aborting due to 1 previous error; 1 warning emitted
 
 For more information about this error, try `rustc --explain E0658`.
diff --git a/tests/ui/stability-attribute/auxiliary/allowed-through-unstable-core.rs b/tests/ui/stability-attribute/auxiliary/allowed-through-unstable-core.rs
index b597009a309..9dfbb451d04 100644
--- a/tests/ui/stability-attribute/auxiliary/allowed-through-unstable-core.rs
+++ b/tests/ui/stability-attribute/auxiliary/allowed-through-unstable-core.rs
@@ -10,5 +10,9 @@ pub mod unstable_module {
     pub trait OldStableTraitAllowedThoughUnstable {}
 
     #[stable(feature = "stable_test_feature", since = "1.2.0")]
+    #[rustc_allowed_through_unstable_modules = "use the new path instead"]
+    pub trait OldStableTraitAllowedThoughUnstableWithDeprecation {}
+
+    #[stable(feature = "stable_test_feature", since = "1.2.0")]
     pub trait NewStableTraitNotAllowedThroughUnstable {}
 }
diff --git a/tests/ui/stability-attribute/missing-const-stability.rs b/tests/ui/stability-attribute/missing-const-stability.rs
index 19820730736..c3e72e83948 100644
--- a/tests/ui/stability-attribute/missing-const-stability.rs
+++ b/tests/ui/stability-attribute/missing-const-stability.rs
@@ -22,6 +22,7 @@ impl Foo {
 #[stable(feature = "stable", since = "1.0.0")]
 #[const_trait]
 pub trait Bar {
+//~^ ERROR trait has missing const stability attribute
     #[stable(feature = "stable", since = "1.0.0")]
     fn fun();
 }
diff --git a/tests/ui/stability-attribute/missing-const-stability.stderr b/tests/ui/stability-attribute/missing-const-stability.stderr
index baa4c34af06..09461e6fb54 100644
--- a/tests/ui/stability-attribute/missing-const-stability.stderr
+++ b/tests/ui/stability-attribute/missing-const-stability.stderr
@@ -4,8 +4,18 @@ error: function has missing const stability attribute
 LL | pub const fn foo() {}
    | ^^^^^^^^^^^^^^^^^^^^^
 
+error: trait has missing const stability attribute
+  --> $DIR/missing-const-stability.rs:24:1
+   |
+LL | / pub trait Bar {
+LL | |
+LL | |     #[stable(feature = "stable", since = "1.0.0")]
+LL | |     fn fun();
+LL | | }
+   | |_^
+
 error: function has missing const stability attribute
-  --> $DIR/missing-const-stability.rs:36:1
+  --> $DIR/missing-const-stability.rs:37:1
    |
 LL | pub const unsafe fn size_of_val<T>(x: *const T) -> usize { 42 }
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -16,5 +26,5 @@ error: associated function has missing const stability attribute
 LL |     pub const fn foo() {}
    |     ^^^^^^^^^^^^^^^^^^^^^
 
-error: aborting due to 3 previous errors
+error: aborting due to 4 previous errors
 
diff --git a/tests/ui/statics/uninhabited-static.rs b/tests/ui/statics/uninhabited-static.rs
index a0f83f45079..0f7c5ae6ef4 100644
--- a/tests/ui/statics/uninhabited-static.rs
+++ b/tests/ui/statics/uninhabited-static.rs
@@ -2,7 +2,7 @@
 #![deny(uninhabited_static)]
 
 enum Void {}
-extern {
+extern "C" {
     static VOID: Void; //~ ERROR static of uninhabited type
     //~| WARN: previously accepted
     static NEVER: !; //~ ERROR static of uninhabited type
diff --git a/tests/ui/target-feature/invalid-attribute.rs b/tests/ui/target-feature/invalid-attribute.rs
index 2f951c4a00a..c0f5b6b2fb2 100644
--- a/tests/ui/target-feature/invalid-attribute.rs
+++ b/tests/ui/target-feature/invalid-attribute.rs
@@ -97,6 +97,7 @@ impl Foo {}
 
 trait Quux {
     fn foo(); //~ NOTE `foo` from trait
+    //~^ NOTE: type in trait
 }
 
 impl Quux for Foo {
@@ -106,6 +107,9 @@ impl Quux for Foo {
     //~| NOTE: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
     fn foo() {}
     //~^ NOTE not an `unsafe` function
+    //~| ERROR: incompatible type for trait
+    //~| NOTE: expected safe fn, found unsafe fn
+    //~| NOTE: expected signature `fn()`
 }
 
 fn main() {
diff --git a/tests/ui/target-feature/invalid-attribute.stderr b/tests/ui/target-feature/invalid-attribute.stderr
index bf48911edec..10fcf65bb9a 100644
--- a/tests/ui/target-feature/invalid-attribute.stderr
+++ b/tests/ui/target-feature/invalid-attribute.stderr
@@ -126,7 +126,7 @@ LL | impl Foo {}
    | ----------- not a function definition
 
 error: attribute should be applied to a function definition
-  --> $DIR/invalid-attribute.rs:112:5
+  --> $DIR/invalid-attribute.rs:116:5
    |
 LL |       #[target_feature(enable = "sse2")]
    |       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -138,7 +138,7 @@ LL | |     }
    | |_____- not a function definition
 
 error: attribute should be applied to a function definition
-  --> $DIR/invalid-attribute.rs:120:5
+  --> $DIR/invalid-attribute.rs:124:5
    |
 LL |     #[target_feature(enable = "sse2")]
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -193,7 +193,7 @@ LL |     fn foo();
    |     --------- `foo` from trait
 
 error[E0658]: `#[target_feature(..)]` can only be applied to `unsafe` functions
-  --> $DIR/invalid-attribute.rs:103:5
+  --> $DIR/invalid-attribute.rs:104:5
    |
 LL |     #[target_feature(enable = "sse2")]
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -205,7 +205,21 @@ LL |     fn foo() {}
    = help: add `#![feature(target_feature_11)]` to the crate attributes to enable
    = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
-error: aborting due to 23 previous errors
+error[E0053]: method `foo` has an incompatible type for trait
+  --> $DIR/invalid-attribute.rs:108:5
+   |
+LL |     fn foo() {}
+   |     ^^^^^^^^ expected safe fn, found unsafe fn
+   |
+note: type in trait
+  --> $DIR/invalid-attribute.rs:99:5
+   |
+LL |     fn foo();
+   |     ^^^^^^^^^
+   = note: expected signature `fn()`
+              found signature `#[target_features] fn()`
+
+error: aborting due to 24 previous errors
 
-Some errors have detailed explanations: E0046, E0658.
+Some errors have detailed explanations: E0046, E0053, E0658.
 For more information about an error, try `rustc --explain E0046`.
diff --git a/tests/ui/traits/const-traits/auxiliary/staged-api.rs b/tests/ui/traits/const-traits/auxiliary/staged-api.rs
index abe22db702c..933a25769dc 100644
--- a/tests/ui/traits/const-traits/auxiliary/staged-api.rs
+++ b/tests/ui/traits/const-traits/auxiliary/staged-api.rs
@@ -4,6 +4,7 @@
 #![stable(feature = "rust1", since = "1.0.0")]
 
 #[stable(feature = "rust1", since = "1.0.0")]
+#[rustc_const_unstable(feature = "unstable", issue = "none")]
 #[const_trait]
 pub trait MyTrait {
     #[stable(feature = "rust1", since = "1.0.0")]
diff --git a/tests/ui/traits/const-traits/call-const-trait-method-pass.rs b/tests/ui/traits/const-traits/call-const-trait-method-pass.rs
index b854b422b3a..3004647ede0 100644
--- a/tests/ui/traits/const-traits/call-const-trait-method-pass.rs
+++ b/tests/ui/traits/const-traits/call-const-trait-method-pass.rs
@@ -1,6 +1,6 @@
 //@ known-bug: #110395
 
-#![feature(const_trait_impl)]
+#![feature(const_trait_impl, const_ops)]
 
 struct Int(i32);
 
diff --git a/tests/ui/traits/const-traits/const-and-non-const-impl.rs b/tests/ui/traits/const-traits/const-and-non-const-impl.rs
index 6b96fcf0ae3..85e2c5d3df6 100644
--- a/tests/ui/traits/const-traits/const-and-non-const-impl.rs
+++ b/tests/ui/traits/const-traits/const-and-non-const-impl.rs
@@ -1,6 +1,6 @@
 //@ known-bug: #110395
 
-#![feature(const_trait_impl)]
+#![feature(const_trait_impl, const_ops)]
 
 pub struct Int(i32);
 
diff --git a/tests/ui/traits/const-traits/cross-crate.stocknc.stderr b/tests/ui/traits/const-traits/cross-crate.stocknc.stderr
index 2358731c901..fb47bf9169f 100644
--- a/tests/ui/traits/const-traits/cross-crate.stocknc.stderr
+++ b/tests/ui/traits/const-traits/cross-crate.stocknc.stderr
@@ -1,13 +1,10 @@
-error[E0658]: cannot call conditionally-const method `<cross_crate::NonConst as cross_crate::MyTrait>::func` in constant functions
+error[E0015]: cannot call non-const method `<cross_crate::NonConst as cross_crate::MyTrait>::func` in constant functions
   --> $DIR/cross-crate.rs:19:14
    |
 LL |     NonConst.func();
    |              ^^^^^^
    |
    = note: calls in constant functions are limited to constant functions, tuple structs and tuple variants
-   = note: see issue #67792 <https://github.com/rust-lang/rust/issues/67792> for more information
-   = help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
-   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
 error[E0658]: cannot call conditionally-const method `<cross_crate::Const as cross_crate::MyTrait>::func` in constant functions
   --> $DIR/cross-crate.rs:22:11
@@ -22,4 +19,5 @@ LL |     Const.func();
 
 error: aborting due to 2 previous errors
 
-For more information about this error, try `rustc --explain E0658`.
+Some errors have detailed explanations: E0015, E0658.
+For more information about an error, try `rustc --explain E0015`.
diff --git a/tests/ui/traits/const-traits/generic-bound.rs b/tests/ui/traits/const-traits/generic-bound.rs
index 5eb236acde2..99de21471b2 100644
--- a/tests/ui/traits/const-traits/generic-bound.rs
+++ b/tests/ui/traits/const-traits/generic-bound.rs
@@ -1,6 +1,6 @@
 //@ check-pass
 
-#![feature(const_trait_impl)]
+#![feature(const_trait_impl, const_ops)]
 
 use std::marker::PhantomData;
 
diff --git a/tests/ui/traits/const-traits/syntactical-unstable.rs b/tests/ui/traits/const-traits/syntactical-unstable.rs
new file mode 100644
index 00000000000..e192e80fabd
--- /dev/null
+++ b/tests/ui/traits/const-traits/syntactical-unstable.rs
@@ -0,0 +1,34 @@
+//@ aux-build:staged-api.rs
+
+// Ensure that we enforce const stability of traits in `~const`/`const` bounds.
+
+#![feature(const_trait_impl)]
+
+use std::ops::Deref;
+
+extern crate staged_api;
+use staged_api::MyTrait;
+
+#[const_trait]
+trait Foo: ~const MyTrait {
+    //~^ ERROR use of unstable const library feature `unstable`
+    type Item: ~const MyTrait;
+    //~^ ERROR use of unstable const library feature `unstable`
+}
+
+const fn where_clause<T>() where T: ~const MyTrait {}
+//~^ ERROR use of unstable const library feature `unstable`
+
+const fn nested<T>() where T: Deref<Target: ~const MyTrait> {}
+//~^ ERROR use of unstable const library feature `unstable`
+
+const fn rpit() -> impl ~const MyTrait { Local }
+//~^ ERROR use of unstable const library feature `unstable`
+
+struct Local;
+impl const MyTrait for Local {
+//~^ ERROR use of unstable const library feature `unstable`
+    fn func() {}
+}
+
+fn main() {}
diff --git a/tests/ui/traits/const-traits/syntactical-unstable.stderr b/tests/ui/traits/const-traits/syntactical-unstable.stderr
new file mode 100644
index 00000000000..a2ce2f2b6e9
--- /dev/null
+++ b/tests/ui/traits/const-traits/syntactical-unstable.stderr
@@ -0,0 +1,67 @@
+error[E0658]: use of unstable const library feature `unstable`
+  --> $DIR/syntactical-unstable.rs:13:19
+   |
+LL | trait Foo: ~const MyTrait {
+   |            ------ ^^^^^^^
+   |            |
+   |            trait is not stable as const yet
+   |
+   = help: add `#![feature(unstable)]` to the crate attributes to enable
+   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
+
+error[E0658]: use of unstable const library feature `unstable`
+  --> $DIR/syntactical-unstable.rs:19:44
+   |
+LL | const fn where_clause<T>() where T: ~const MyTrait {}
+   |                                     ------ ^^^^^^^
+   |                                     |
+   |                                     trait is not stable as const yet
+   |
+   = help: add `#![feature(unstable)]` to the crate attributes to enable
+   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
+
+error[E0658]: use of unstable const library feature `unstable`
+  --> $DIR/syntactical-unstable.rs:22:52
+   |
+LL | const fn nested<T>() where T: Deref<Target: ~const MyTrait> {}
+   |                                             ------ ^^^^^^^
+   |                                             |
+   |                                             trait is not stable as const yet
+   |
+   = help: add `#![feature(unstable)]` to the crate attributes to enable
+   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
+
+error[E0658]: use of unstable const library feature `unstable`
+  --> $DIR/syntactical-unstable.rs:25:32
+   |
+LL | const fn rpit() -> impl ~const MyTrait { Local }
+   |                         ------ ^^^^^^^
+   |                         |
+   |                         trait is not stable as const yet
+   |
+   = help: add `#![feature(unstable)]` to the crate attributes to enable
+   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
+
+error[E0658]: use of unstable const library feature `unstable`
+  --> $DIR/syntactical-unstable.rs:29:12
+   |
+LL | impl const MyTrait for Local {
+   |            ^^^^^^^ trait is not stable as const yet
+   |
+   = help: add `#![feature(unstable)]` to the crate attributes to enable
+   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
+
+error[E0658]: use of unstable const library feature `unstable`
+  --> $DIR/syntactical-unstable.rs:15:23
+   |
+LL |     type Item: ~const MyTrait;
+   |                ------ ^^^^^^^
+   |                |
+   |                trait is not stable as const yet
+   |
+   = help: add `#![feature(unstable)]` to the crate attributes to enable
+   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
+
+error: aborting due to 6 previous errors
+
+For more information about this error, try `rustc --explain E0658`.
diff --git a/tests/ui/traits/const-traits/trait-default-body-stability.rs b/tests/ui/traits/const-traits/trait-default-body-stability.rs
index 5f7486eb176..567f1b3c284 100644
--- a/tests/ui/traits/const-traits/trait-default-body-stability.rs
+++ b/tests/ui/traits/const-traits/trait-default-body-stability.rs
@@ -38,6 +38,7 @@ impl const FromResidual for T {
 }
 
 #[stable(feature = "foo", since = "1.0")]
+#[rustc_const_unstable(feature = "const_tr", issue = "none")]
 #[const_trait]
 pub trait Tr {
     #[stable(feature = "foo", since = "1.0")]
diff --git a/tests/ui/traits/const-traits/trait-default-body-stability.stderr b/tests/ui/traits/const-traits/trait-default-body-stability.stderr
index 77b81211e81..a13d9a1e075 100644
--- a/tests/ui/traits/const-traits/trait-default-body-stability.stderr
+++ b/tests/ui/traits/const-traits/trait-default-body-stability.stderr
@@ -17,7 +17,7 @@ LL | impl const FromResidual for T {
    = note: adding a non-const method body in the future would be a breaking change
 
 error[E0015]: `?` is not allowed on `T` in constant functions
-  --> $DIR/trait-default-body-stability.rs:45:9
+  --> $DIR/trait-default-body-stability.rs:46:9
    |
 LL |         T?
    |         ^^
@@ -25,7 +25,7 @@ LL |         T?
    = note: calls in constant functions are limited to constant functions, tuple structs and tuple variants
 
 error[E0015]: `?` is not allowed on `T` in constant functions
-  --> $DIR/trait-default-body-stability.rs:45:9
+  --> $DIR/trait-default-body-stability.rs:46:9
    |
 LL |         T?
    |         ^^
diff --git a/tests/ui/traits/next-solver/known-type-outlives-has-constraints.rs b/tests/ui/traits/next-solver/known-type-outlives-has-constraints.rs
new file mode 100644
index 00000000000..55fea005ea1
--- /dev/null
+++ b/tests/ui/traits/next-solver/known-type-outlives-has-constraints.rs
@@ -0,0 +1,13 @@
+//@ compile-flags: -Znext-solver
+//@ check-pass
+
+trait Norm {
+    type Out;
+}
+impl<'a, T: 'a> Norm for &'a T {
+    type Out = T;
+}
+
+fn hello<'a, T: 'a>() where <&'a T as Norm>::Out: 'a {}
+
+fn main() {}
diff --git a/tests/ui/traits/trait-upcasting/impossible-method-modulo-binders-2.rs b/tests/ui/traits/trait-upcasting/impossible-method-modulo-binders-2.rs
new file mode 100644
index 00000000000..c03b5145aa7
--- /dev/null
+++ b/tests/ui/traits/trait-upcasting/impossible-method-modulo-binders-2.rs
@@ -0,0 +1,39 @@
+//@ build-pass
+//@ revisions: current next
+//@ ignore-compare-mode-next-solver (explicit revisions)
+//@[next] compile-flags: -Znext-solver
+// Regression test for #135462.
+#![allow(coherence_leak_check)]
+
+type A = fn(&'static ());
+type B = fn(&());
+
+trait Bound<P: WithAssoc>: From<GetAssoc<P>> {
+}
+impl Bound<B> for String {}
+
+trait Trt<T> {
+    fn __(&self, x: T) where T: Bound<A> {
+        T::from(());
+    }
+}
+
+impl<T, S> Trt<T> for S {}
+
+type GetAssoc<T> = <T as WithAssoc>::Ty;
+
+trait WithAssoc {
+    type Ty;
+}
+
+impl WithAssoc for B {
+    type Ty = String;
+}
+
+impl WithAssoc for A {
+    type Ty = ();
+}
+
+fn main() {
+    let x: &'static dyn Trt<String> = &();
+}
diff --git a/tests/ui/traits/trait-upcasting/impossible-method-modulo-binders.rs b/tests/ui/traits/trait-upcasting/impossible-method-modulo-binders.rs
new file mode 100644
index 00000000000..63ad1c0a060
--- /dev/null
+++ b/tests/ui/traits/trait-upcasting/impossible-method-modulo-binders.rs
@@ -0,0 +1,40 @@
+//@ build-pass
+//@ revisions: current next
+//@ ignore-compare-mode-next-solver (explicit revisions)
+//@[next] compile-flags: -Znext-solver
+
+trait Foo {}
+impl Foo for fn(&'static ()) {}
+
+trait Bar {
+    type Assoc: Default;
+}
+impl<T: Foo> Bar for T {
+    type Assoc = usize;
+}
+impl Bar for fn(&()) {
+    type Assoc = ();
+}
+
+fn needs_foo<T: Foo>() -> usize {
+    needs_bar::<T>()
+}
+
+fn needs_bar<T: Bar>() -> <T as Bar>::Assoc {
+    Default::default()
+}
+
+trait Evil<T> {
+    fn bad(&self)
+    where
+        T: Foo,
+    {
+        needs_foo::<T>();
+    }
+}
+
+impl Evil<fn(&())> for () {}
+
+fn main() {
+    let x: &dyn Evil<fn(&())> = &();
+}
diff --git a/tests/ui/traits/trait-upcasting/prefer-lower-candidates.rs b/tests/ui/traits/trait-upcasting/prefer-lower-candidates.rs
new file mode 100644
index 00000000000..4bc59b09fb5
--- /dev/null
+++ b/tests/ui/traits/trait-upcasting/prefer-lower-candidates.rs
@@ -0,0 +1,29 @@
+//@ revisions: current next
+//@ ignore-compare-mode-next-solver (explicit revisions)
+//@[next] compile-flags: -Znext-solver
+//@ check-pass
+
+// Ensure we don't have ambiguity when upcasting to two supertraits
+// that are identical modulo normalization.
+
+#![feature(trait_upcasting)]
+
+trait Supertrait<T> {
+    fn method(&self) {}
+}
+impl<T> Supertrait<T> for () {}
+
+trait Identity {
+    type Selff;
+}
+impl<Selff> Identity for Selff {
+    type Selff = Selff;
+}
+trait Trait<P>: Supertrait<()> + Supertrait<<P as Identity>::Selff> {}
+
+impl<P> Trait<P> for () {}
+
+fn main() {
+    let x: &dyn Trait<()> = &();
+    let x: &dyn Supertrait<()> = x;
+}
diff --git a/tests/ui/unpretty/expanded-exhaustive.rs b/tests/ui/unpretty/expanded-exhaustive.rs
index 26c253d049b..31af323ecda 100644
--- a/tests/ui/unpretty/expanded-exhaustive.rs
+++ b/tests/ui/unpretty/expanded-exhaustive.rs
@@ -452,15 +452,15 @@ mod items {
     /// ItemKind::Fn
     mod item_fn {
         pub const unsafe extern "C" fn f() {}
-        pub async unsafe extern fn g() {}
+        pub async unsafe extern "C" fn g() {}
         fn h<'a, T>() where T: 'a {}
 
         trait TraitItems {
-            unsafe extern fn f();
+            unsafe extern "C" fn f();
         }
 
         impl TraitItems for _ {
-            default unsafe extern fn f() {}
+            default unsafe extern "C" fn f() {}
         }
     }
 
@@ -472,7 +472,7 @@ mod items {
     /// ItemKind::ForeignMod
     mod item_foreign_mod {
         unsafe extern "C++" {}
-        unsafe extern {}
+        unsafe extern "C" {}
     }
 
     /// ItemKind::GlobalAsm
diff --git a/tests/ui/unpretty/expanded-exhaustive.stdout b/tests/ui/unpretty/expanded-exhaustive.stdout
index bd7aa1117cc..11066c90edb 100644
--- a/tests/ui/unpretty/expanded-exhaustive.stdout
+++ b/tests/ui/unpretty/expanded-exhaustive.stdout
@@ -433,13 +433,13 @@ mod items {
     /// ItemKind::Fn
     mod item_fn {
         pub const unsafe extern "C" fn f() {}
-        pub async unsafe extern fn g() {}
+        pub async unsafe extern "C" fn g() {}
         fn h<'a, T>() where T: 'a {}
         trait TraitItems {
-            unsafe extern fn f();
+            unsafe extern "C" fn f();
         }
         impl TraitItems for _ {
-            default unsafe extern fn f() {}
+            default unsafe extern "C" fn f() {}
         }
     }
     /// ItemKind::Mod
@@ -447,7 +447,7 @@ mod items {
     /// ItemKind::ForeignMod
     mod item_foreign_mod {
         unsafe extern "C++" {}
-        unsafe extern {}
+        unsafe extern "C" {}
     }
     /// ItemKind::GlobalAsm
     mod item_global_asm {