Rollup of 7 pull requests

compiler/rustc_ast/src/visit.rs

@@ -268,8 +268,8 @@ pub trait Visitor<'ast>: Sized {
     fn visit_fn_ret_ty(&mut self, ret_ty: &'ast FnRetTy) -> Self::Result {
         walk_fn_ret_ty(self, ret_ty)
     }
-    fn visit_fn_header(&mut self, _header: &'ast FnHeader) -> Self::Result {
-        Self::Result::output()
+    fn visit_fn_header(&mut self, header: &'ast FnHeader) -> Self::Result {
+        walk_fn_header(self, header)
     }
     fn visit_expr_field(&mut self, f: &'ast ExprField) -> Self::Result {
         walk_expr_field(self, f)
@@ -292,6 +292,9 @@ pub trait Visitor<'ast>: Sized {
     fn visit_capture_by(&mut self, _capture_by: &'ast CaptureBy) -> Self::Result {
         Self::Result::output()
     }
+    fn visit_coroutine_kind(&mut self, _coroutine_kind: &'ast CoroutineKind) -> Self::Result {
+        Self::Result::output()
+    }
 }
 
 pub fn walk_crate<'a, V: Visitor<'a>>(visitor: &mut V, krate: &'a Crate) -> V::Result {
@@ -813,6 +816,12 @@ pub fn walk_fn_ret_ty<'a, V: Visitor<'a>>(visitor: &mut V, ret_ty: &'a FnRetTy)
     V::Result::output()
 }
 
+pub fn walk_fn_header<'a, V: Visitor<'a>>(visitor: &mut V, fn_header: &'a FnHeader) -> V::Result {
+    let FnHeader { safety: _, coroutine_kind, constness: _, ext: _ } = fn_header;
+    visit_opt!(visitor, visit_coroutine_kind, coroutine_kind.as_ref());
+    V::Result::output()
+}
+
 pub fn walk_fn_decl<'a, V: Visitor<'a>>(
     visitor: &mut V,
     FnDecl { inputs, output }: &'a FnDecl,
@@ -830,8 +839,9 @@ pub fn walk_fn<'a, V: Visitor<'a>>(visitor: &mut V, kind: FnKind<'a>) -> V::Resu
             try_visit!(walk_fn_decl(visitor, decl));
             visit_opt!(visitor, visit_block, body);
         }
-        FnKind::Closure(binder, _coroutine_kind, decl, body) => {
+        FnKind::Closure(binder, coroutine_kind, decl, body) => {
             try_visit!(visitor.visit_closure_binder(binder));
+            visit_opt!(visitor, visit_coroutine_kind, coroutine_kind.as_ref());
             try_visit!(walk_fn_decl(visitor, decl));
             try_visit!(visitor.visit_expr(body));
         }

compiler/rustc_ast_lowering/src/lib.rs

@@ -738,7 +738,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         allow_internal_unstable: Option<Lrc<[Symbol]>>,
     ) -> Span {
         self.tcx.with_stable_hashing_context(|hcx| {
-            span.mark_with_reason(allow_internal_unstable, reason, self.tcx.sess.edition(), hcx)
+            span.mark_with_reason(allow_internal_unstable, reason, span.edition(), hcx)
         })
     }
 

compiler/rustc_lint/src/early.rs

@@ -68,6 +68,10 @@ impl<'a, T: EarlyLintPass> EarlyContextAndPass<'a, T> {
 }
 
 impl<'a, T: EarlyLintPass> ast_visit::Visitor<'a> for EarlyContextAndPass<'a, T> {
+    fn visit_coroutine_kind(&mut self, coroutine_kind: &'a ast::CoroutineKind) -> Self::Result {
+        self.check_id(coroutine_kind.closure_id());
+    }
+
     fn visit_param(&mut self, param: &'a ast::Param) {
         self.with_lint_attrs(param.id, &param.attrs, |cx| {
             lint_callback!(cx, check_param, param);
@@ -111,17 +115,6 @@ impl<'a, T: EarlyLintPass> ast_visit::Visitor<'a> for EarlyContextAndPass<'a, T>
         self.with_lint_attrs(e.id, &e.attrs, |cx| {
             lint_callback!(cx, check_expr, e);
             ast_visit::walk_expr(cx, e);
-            // Explicitly check for lints associated with 'closure_id', since
-            // it does not have a corresponding AST node
-            match e.kind {
-                ast::ExprKind::Closure(box ast::Closure {
-                    coroutine_kind: Some(coroutine_kind),
-                    ..
-                }) => {
-                    cx.check_id(coroutine_kind.closure_id());
-                }
-                _ => {}
-            }
             lint_callback!(cx, check_expr_post, e);
         })
     }
@@ -156,14 +149,6 @@ impl<'a, T: EarlyLintPass> ast_visit::Visitor<'a> for EarlyContextAndPass<'a, T>
         lint_callback!(self, check_fn, fk, span, id);
         self.check_id(id);
         ast_visit::walk_fn(self, fk);
-
-        // Explicitly check for lints associated with 'closure_id', since
-        // it does not have a corresponding AST node
-        if let ast_visit::FnKind::Fn(_, _, sig, _, _, _) = fk {
-            if let Some(coroutine_kind) = sig.header.coroutine_kind {
-                self.check_id(coroutine_kind.closure_id());
-            }
-        }
     }
 
     fn visit_variant_data(&mut self, s: &'a ast::VariantData) {

compiler/rustc_lint/src/unused.rs

@@ -584,6 +584,7 @@ enum UnusedDelimsCtx {
     MatchScrutineeExpr,
     ReturnValue,
     BlockRetValue,
+    BreakValue,
     LetScrutineeExpr,
     ArrayLenExpr,
     AnonConst,
@@ -605,6 +606,7 @@ impl From<UnusedDelimsCtx> for &'static str {
             UnusedDelimsCtx::MatchScrutineeExpr => "`match` scrutinee expression",
             UnusedDelimsCtx::ReturnValue => "`return` value",
             UnusedDelimsCtx::BlockRetValue => "block return value",
+            UnusedDelimsCtx::BreakValue => "`break` value",
             UnusedDelimsCtx::LetScrutineeExpr => "`let` scrutinee expression",
             UnusedDelimsCtx::ArrayLenExpr | UnusedDelimsCtx::AnonConst => "const expression",
             UnusedDelimsCtx::MatchArmExpr => "match arm expression",
@@ -913,6 +915,10 @@ trait UnusedDelimLint {
                 (value, UnusedDelimsCtx::ReturnValue, false, Some(left), None, true)
             }
 
+            Break(_, Some(ref value)) => {
+                (value, UnusedDelimsCtx::BreakValue, false, None, None, true)
+            }
+
             Index(_, ref value, _) => (value, UnusedDelimsCtx::IndexExpr, false, None, None, false),
 
             Assign(_, ref value, _) | AssignOp(.., ref value) => {
@@ -1063,6 +1069,9 @@ impl UnusedDelimLint for UnusedParens {
                                 _,
                                 _,
                             ) if node.is_lazy()))
+                    && !((ctx == UnusedDelimsCtx::ReturnValue
+                        || ctx == UnusedDelimsCtx::BreakValue)
+                        && matches!(inner.kind, ast::ExprKind::Assign(_, _, _)))
                 {
                     self.emit_unused_delims_expr(cx, value, ctx, left_pos, right_pos, is_kw)
                 }

compiler/rustc_lint_defs/src/builtin.rs

@@ -4185,7 +4185,7 @@ declare_lint! {
     Warn,
     "never type fallback affecting unsafe function calls",
     @future_incompatible = FutureIncompatibleInfo {
-        reason: FutureIncompatibilityReason::FutureReleaseSemanticsChange,
+        reason: FutureIncompatibilityReason::EditionAndFutureReleaseSemanticsChange(Edition::Edition2024),
         reference: "issue #123748 <https://github.com/rust-lang/rust/issues/123748>",
     };
     @edition Edition2024 => Deny;
@@ -4239,7 +4239,7 @@ declare_lint! {
     Warn,
     "never type fallback affecting unsafe function calls",
     @future_incompatible = FutureIncompatibleInfo {
-        reason: FutureIncompatibilityReason::FutureReleaseErrorDontReportInDeps,
+        reason: FutureIncompatibilityReason::EditionAndFutureReleaseError(Edition::Edition2024),
         reference: "issue #123748 <https://github.com/rust-lang/rust/issues/123748>",
     };
     report_in_external_macro

compiler/rustc_lint_defs/src/lib.rs

@@ -381,6 +381,8 @@ pub enum FutureIncompatibilityReason {
     /// hard errors (and the lint removed). Preferably when there is some
     /// confidence that the number of impacted projects is very small (few
     /// should have a broken dependency in their dependency tree).
+    ///
+    /// [`EditionAndFutureReleaseError`]: FutureIncompatibilityReason::EditionAndFutureReleaseError
     FutureReleaseErrorReportInDeps,
     /// Code that changes meaning in some way in a
     /// future release.
@@ -419,6 +421,28 @@ pub enum FutureIncompatibilityReason {
     /// slightly changes the text of the diagnostic, but is otherwise the
     /// same.
     EditionSemanticsChange(Edition),
+    /// This will be an error in the provided edition *and* in a future
+    /// release.
+    ///
+    /// This variant a combination of [`FutureReleaseErrorDontReportInDeps`]
+    /// and [`EditionError`]. This is useful in rare cases when we
+    /// want to have "preview" of a breaking change in an edition, but do a
+    /// breaking change later on all editions anyway.
+    ///
+    /// [`EditionError`]: FutureIncompatibilityReason::EditionError
+    /// [`FutureReleaseErrorDontReportInDeps`]: FutureIncompatibilityReason::FutureReleaseErrorDontReportInDeps
+    EditionAndFutureReleaseError(Edition),
+    /// This will change meaning in the provided edition *and* in a future
+    /// release.
+    ///
+    /// This variant a combination of [`FutureReleaseSemanticsChange`]
+    /// and [`EditionSemanticsChange`]. This is useful in rare cases when we
+    /// want to have "preview" of a breaking change in an edition, but do a
+    /// breaking change later on all editions anyway.
+    ///
+    /// [`EditionSemanticsChange`]: FutureIncompatibilityReason::EditionSemanticsChange
+    /// [`FutureReleaseSemanticsChange`]: FutureIncompatibilityReason::FutureReleaseSemanticsChange
+    EditionAndFutureReleaseSemanticsChange(Edition),
     /// A custom reason.
     ///
     /// Choose this variant if the built-in text of the diagnostic of the
@@ -431,9 +455,15 @@ pub enum FutureIncompatibilityReason {
 impl FutureIncompatibilityReason {
     pub fn edition(self) -> Option<Edition> {
         match self {
-            Self::EditionError(e) => Some(e),
-            Self::EditionSemanticsChange(e) => Some(e),
-            _ => None,
+            Self::EditionError(e)
+            | Self::EditionSemanticsChange(e)
+            | Self::EditionAndFutureReleaseError(e)
+            | Self::EditionAndFutureReleaseSemanticsChange(e) => Some(e),
+
+            FutureIncompatibilityReason::FutureReleaseErrorDontReportInDeps
+            | FutureIncompatibilityReason::FutureReleaseErrorReportInDeps
+            | FutureIncompatibilityReason::FutureReleaseSemanticsChange
+            | FutureIncompatibilityReason::Custom(_) => None,
         }
     }
 }

compiler/rustc_middle/src/lint.rs

@@ -382,6 +382,17 @@ pub fn lint_level(
                 FutureIncompatibilityReason::EditionSemanticsChange(edition) => {
                     format!("this changes meaning in Rust {edition}")
                 }
+                FutureIncompatibilityReason::EditionAndFutureReleaseError(edition) => {
+                    format!(
+                        "this was previously accepted by the compiler but is being phased out; \
+                         it will become a hard error in Rust {edition} and in a future release in all editions!"
+                    )
+                }
+                FutureIncompatibilityReason::EditionAndFutureReleaseSemanticsChange(edition) => {
+                    format!(
+                        "this changes meaning in Rust {edition} and in a future release in all editions!"
+                    )
+                }
                 FutureIncompatibilityReason::Custom(reason) => reason.to_owned(),
             };
 

tests/ui/delegation/unsupported.rs

@@ -10,15 +10,11 @@ mod opaque {
     mod to_reuse {
         use super::Trait;
 
-        pub fn opaque_ret() -> impl Trait { unimplemented!() }
-        //~^ warn: this function depends on never type fallback being `()`
-        //~| warn: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+        pub fn opaque_ret() -> impl Trait { () }
     }
 
     trait ToReuse {
-        fn opaque_ret() -> impl Trait { unimplemented!() }
-        //~^ warn: this function depends on never type fallback being `()`
-        //~| warn: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+        fn opaque_ret() -> impl Trait { () }
     }
 
     // FIXME: Inherited `impl Trait`s create query cycles when used inside trait impls.

tests/ui/delegation/unsupported.stderr

@@ -1,74 +1,43 @@
-error[E0391]: cycle detected when computing type of `opaque::<impl at $DIR/unsupported.rs:25:5: 25:24>::{synthetic#0}`
-  --> $DIR/unsupported.rs:26:25
+error[E0391]: cycle detected when computing type of `opaque::<impl at $DIR/unsupported.rs:21:5: 21:24>::{synthetic#0}`
+  --> $DIR/unsupported.rs:22:25
    |
 LL |         reuse to_reuse::opaque_ret;
    |                         ^^^^^^^^^^
    |
 note: ...which requires comparing an impl and trait method signature, inferring any hidden `impl Trait` types in the process...
-  --> $DIR/unsupported.rs:26:25
+  --> $DIR/unsupported.rs:22:25
    |
 LL |         reuse to_reuse::opaque_ret;
    |                         ^^^^^^^^^^
-   = note: ...which again requires computing type of `opaque::<impl at $DIR/unsupported.rs:25:5: 25:24>::{synthetic#0}`, completing the cycle
-note: cycle used when checking that `opaque::<impl at $DIR/unsupported.rs:25:5: 25:24>` is well-formed
-  --> $DIR/unsupported.rs:25:5
+   = note: ...which again requires computing type of `opaque::<impl at $DIR/unsupported.rs:21:5: 21:24>::{synthetic#0}`, completing the cycle
+note: cycle used when checking that `opaque::<impl at $DIR/unsupported.rs:21:5: 21:24>` is well-formed
+  --> $DIR/unsupported.rs:21:5
    |
 LL |     impl ToReuse for u8 {
    |     ^^^^^^^^^^^^^^^^^^^
    = note: see https://rustc-dev-guide.rust-lang.org/overview.html#queries and https://rustc-dev-guide.rust-lang.org/query.html for more information
 
-warning: this function depends on never type fallback being `()`
-  --> $DIR/unsupported.rs:13:9
-   |
-LL |         pub fn opaque_ret() -> impl Trait { unimplemented!() }
-   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   |
-   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
-   = note: for more information, see issue #123748 <https://github.com/rust-lang/rust/issues/123748>
-   = help: specify the types explicitly
-note: in edition 2024, the requirement `!: opaque::Trait` will fail
-  --> $DIR/unsupported.rs:13:32
-   |
-LL |         pub fn opaque_ret() -> impl Trait { unimplemented!() }
-   |                                ^^^^^^^^^^
-   = note: `#[warn(dependency_on_unit_never_type_fallback)]` on by default
-
-warning: this function depends on never type fallback being `()`
-  --> $DIR/unsupported.rs:19:9
-   |
-LL |         fn opaque_ret() -> impl Trait { unimplemented!() }
-   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   |
-   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
-   = note: for more information, see issue #123748 <https://github.com/rust-lang/rust/issues/123748>
-   = help: specify the types explicitly
-note: in edition 2024, the requirement `!: opaque::Trait` will fail
-  --> $DIR/unsupported.rs:19:28
-   |
-LL |         fn opaque_ret() -> impl Trait { unimplemented!() }
-   |                            ^^^^^^^^^^
-
-error[E0391]: cycle detected when computing type of `opaque::<impl at $DIR/unsupported.rs:28:5: 28:25>::{synthetic#0}`
-  --> $DIR/unsupported.rs:29:24
+error[E0391]: cycle detected when computing type of `opaque::<impl at $DIR/unsupported.rs:24:5: 24:25>::{synthetic#0}`
+  --> $DIR/unsupported.rs:25:24
    |
 LL |         reuse ToReuse::opaque_ret;
    |                        ^^^^^^^^^^
    |
 note: ...which requires comparing an impl and trait method signature, inferring any hidden `impl Trait` types in the process...
-  --> $DIR/unsupported.rs:29:24
+  --> $DIR/unsupported.rs:25:24
    |
 LL |         reuse ToReuse::opaque_ret;
    |                        ^^^^^^^^^^
-   = note: ...which again requires computing type of `opaque::<impl at $DIR/unsupported.rs:28:5: 28:25>::{synthetic#0}`, completing the cycle
-note: cycle used when checking that `opaque::<impl at $DIR/unsupported.rs:28:5: 28:25>` is well-formed
-  --> $DIR/unsupported.rs:28:5
+   = note: ...which again requires computing type of `opaque::<impl at $DIR/unsupported.rs:24:5: 24:25>::{synthetic#0}`, completing the cycle
+note: cycle used when checking that `opaque::<impl at $DIR/unsupported.rs:24:5: 24:25>` is well-formed
+  --> $DIR/unsupported.rs:24:5
    |
 LL |     impl ToReuse for u16 {
    |     ^^^^^^^^^^^^^^^^^^^^
    = note: see https://rustc-dev-guide.rust-lang.org/overview.html#queries and https://rustc-dev-guide.rust-lang.org/query.html for more information
 
 error: recursive delegation is not supported yet
-  --> $DIR/unsupported.rs:42:22
+  --> $DIR/unsupported.rs:38:22
    |
 LL |         pub reuse to_reuse2::foo;
    |                              --- callee defined here
@@ -77,14 +46,14 @@ LL |     reuse to_reuse1::foo;
    |                      ^^^
 
 error[E0283]: type annotations needed
-  --> $DIR/unsupported.rs:52:18
+  --> $DIR/unsupported.rs:48:18
    |
 LL |     reuse Trait::foo;
    |                  ^^^ cannot infer type
    |
    = note: cannot satisfy `_: effects::Trait`
 
-error: aborting due to 4 previous errors; 2 warnings emitted
+error: aborting due to 4 previous errors
 
 Some errors have detailed explanations: E0283, E0391.
 For more information about an error, try `rustc --explain E0283`.

tests/ui/editions/never-type-fallback-breaking.e2021.fixed

@@ -16,7 +16,7 @@ fn main() {
 
 fn m() {
     //[e2021]~^ this function depends on never type fallback being `()`
-    //[e2021]~| this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+    //[e2021]~| this was previously accepted by the compiler but is being phased out; it will become a hard error in Rust 2024 and in a future release in all editions!
     let x: () = match true {
         true => Default::default(),
         //[e2024]~^ error: the trait bound `!: Default` is not satisfied
@@ -28,7 +28,7 @@ fn m() {
 
 fn q() -> Option<()> {
     //[e2021]~^ this function depends on never type fallback being `()`
-    //[e2021]~| this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+    //[e2021]~| this was previously accepted by the compiler but is being phased out; it will become a hard error in Rust 2024 and in a future release in all editions!
     fn deserialize<T: Default>() -> Option<T> {
         Some(T::default())
     }
@@ -45,7 +45,7 @@ fn help<'a: 'a, T: Into<()>, U>(_: U) -> Result<T, ()> {
 }
 fn meow() -> Result<(), ()> {
     //[e2021]~^ this function depends on never type fallback being `()`
-    //[e2021]~| this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+    //[e2021]~| this was previously accepted by the compiler but is being phased out; it will become a hard error in Rust 2024 and in a future release in all editions!
     help::<(), _>(1)?;
     //[e2024]~^ error: the trait bound `(): From<!>` is not satisfied
     Ok(())

tests/ui/editions/never-type-fallback-breaking.e2021.stderr

@@ -4,7 +4,7 @@ warning: this function depends on never type fallback being `()`
 LL | fn m() {
    | ^^^^^^
    |
-   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in Rust 2024 and in a future release in all editions!
    = note: for more information, see issue #123748 <https://github.com/rust-lang/rust/issues/123748>
    = help: specify the types explicitly
 note: in edition 2024, the requirement `!: Default` will fail
@@ -24,7 +24,7 @@ warning: this function depends on never type fallback being `()`
 LL | fn q() -> Option<()> {
    | ^^^^^^^^^^^^^^^^^^^^
    |
-   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in Rust 2024 and in a future release in all editions!
    = note: for more information, see issue #123748 <https://github.com/rust-lang/rust/issues/123748>
    = help: specify the types explicitly
 note: in edition 2024, the requirement `!: Default` will fail
@@ -43,7 +43,7 @@ warning: this function depends on never type fallback being `()`
 LL | fn meow() -> Result<(), ()> {
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
-   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in Rust 2024 and in a future release in all editions!
    = note: for more information, see issue #123748 <https://github.com/rust-lang/rust/issues/123748>
    = help: specify the types explicitly
 note: in edition 2024, the requirement `(): From<!>` will fail

tests/ui/editions/never-type-fallback-breaking.rs

@@ -16,7 +16,7 @@ fn main() {
 
 fn m() {
     //[e2021]~^ this function depends on never type fallback being `()`
-    //[e2021]~| this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+    //[e2021]~| this was previously accepted by the compiler but is being phased out; it will become a hard error in Rust 2024 and in a future release in all editions!
     let x = match true {
         true => Default::default(),
         //[e2024]~^ error: the trait bound `!: Default` is not satisfied
@@ -28,7 +28,7 @@ fn m() {
 
 fn q() -> Option<()> {
     //[e2021]~^ this function depends on never type fallback being `()`
-    //[e2021]~| this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+    //[e2021]~| this was previously accepted by the compiler but is being phased out; it will become a hard error in Rust 2024 and in a future release in all editions!
     fn deserialize<T: Default>() -> Option<T> {
         Some(T::default())
     }
@@ -45,7 +45,7 @@ fn help<'a: 'a, T: Into<()>, U>(_: U) -> Result<T, ()> {
 }
 fn meow() -> Result<(), ()> {
     //[e2021]~^ this function depends on never type fallback being `()`
-    //[e2021]~| this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+    //[e2021]~| this was previously accepted by the compiler but is being phased out; it will become a hard error in Rust 2024 and in a future release in all editions!
     help(1)?;
     //[e2024]~^ error: the trait bound `(): From<!>` is not satisfied
     Ok(())

tests/ui/impl-trait/precise-capturing/auxiliary/no-use-macro.rs

@@ -0,0 +1,20 @@
+// A macro_rules macro in 2015 that has an RPIT without `use<>` that would
+// cause a problem with 2024 capturing rules.
+
+#[macro_export]
+macro_rules! macro_rpit {
+    () => {
+        fn test_mbe(x: &Vec<i32>) -> impl std::fmt::Display {
+            x[0]
+        }
+
+        pub fn from_mbe() {
+            let mut x = vec![];
+            x.push(1);
+
+            let element = test_mbe(&x);
+            x.push(2);
+            println!("{element}");
+        }
+    };
+}

tests/ui/impl-trait/precise-capturing/auxiliary/no-use-pm.rs

@@ -0,0 +1,29 @@
+// A proc-macro in 2015 that has an RPIT without `use<>` that would cause a
+// problem with 2024 capturing rules.
+
+//@ force-host
+//@ no-prefer-dynamic
+
+#![crate_type = "proc-macro"]
+
+extern crate proc_macro;
+use proc_macro::TokenStream;
+
+#[proc_macro]
+pub fn pm_rpit(input: TokenStream) -> TokenStream {
+    "fn test_pm(x: &Vec<i32>) -> impl std::fmt::Display {
+    x[0]
+}
+
+pub fn from_pm() {
+    let mut x = vec![];
+    x.push(1);
+
+    let element = test_pm(&x);
+    x.push(2);
+    println!(\"{element}\");
+}
+"
+    .parse()
+    .unwrap()
+}

tests/ui/impl-trait/precise-capturing/external-macro.rs

@@ -0,0 +1,26 @@
+// Tests that code generated from an external macro (MBE and proc-macro) that
+// has an RPIT will not fail when the call-site is 2024.
+// https://github.com/rust-lang/rust/issues/132917
+
+//@ aux-crate: no_use_pm=no-use-pm.rs
+//@ aux-crate: no_use_macro=no-use-macro.rs
+//@ edition: 2024
+//@ compile-flags:-Z unstable-options
+//@ check-pass
+
+no_use_pm::pm_rpit!{}
+
+no_use_macro::macro_rpit!{}
+
+fn main() {
+    let mut x = vec![];
+    x.push(1);
+
+    let element = test_pm(&x);
+    x.push(2);
+    println!("{element}");
+
+    let element = test_mbe(&x);
+    x.push(2);
+    println!("{element}");
+}

tests/ui/lint/unused/issue-54538-unused-parens-lint.fixed

@@ -10,7 +10,7 @@
     unused_mut,
     unused_variables
 )]
-#![deny(unused_parens)]
+#![deny(unused_parens, unused_braces)]
 
 fn lint_on_top_level() {
     let a = 0; //~ ERROR unnecessary parentheses around pattern
@@ -43,8 +43,10 @@ fn no_lint_ops() {
 fn lint_break_if_not_followed_by_block() {
     #![allow(unreachable_code)]
     loop { if break {} } //~ ERROR unnecessary parentheses
-    loop { if break ({ println!("hello") }) {} } //~ ERROR unnecessary parentheses
-    loop { if (break { println!("hello") }) {} }
+    loop { if break { println!("hello") } {} }
+    //~^ ERROR unnecessary parentheses around `if` condition
+    //~| ERROR unnecessary parentheses around `break` value
+    loop { if (break println!("hello")) {} } //~ ERROR unnecessary braces around `break` value
 }
 
 // Don't lint in these cases (#64106).

tests/ui/lint/unused/issue-54538-unused-parens-lint.rs

@@ -10,7 +10,7 @@
     unused_mut,
     unused_variables
 )]
-#![deny(unused_parens)]
+#![deny(unused_parens, unused_braces)]
 
 fn lint_on_top_level() {
     let (a) = 0; //~ ERROR unnecessary parentheses around pattern
@@ -43,8 +43,10 @@ fn no_lint_ops() {
 fn lint_break_if_not_followed_by_block() {
     #![allow(unreachable_code)]
     loop { if (break) {} } //~ ERROR unnecessary parentheses
-    loop { if (break ({ println!("hello") })) {} } //~ ERROR unnecessary parentheses
-    loop { if (break { println!("hello") }) {} }
+    loop { if (break ({ println!("hello") })) {} }
+    //~^ ERROR unnecessary parentheses around `if` condition
+    //~| ERROR unnecessary parentheses around `break` value
+    loop { if (break { println!("hello") }) {} } //~ ERROR unnecessary braces around `break` value
 }
 
 // Don't lint in these cases (#64106).

tests/ui/lint/unused/issue-54538-unused-parens-lint.stderr

@@ -7,7 +7,7 @@ LL |     let (a) = 0;
 note: the lint level is defined here
   --> $DIR/issue-54538-unused-parens-lint.rs:13:9
    |
-LL | #![deny(unused_parens)]
+LL | #![deny(unused_parens, unused_braces)]
    |         ^^^^^^^^^^^^^
 help: remove these parentheses
    |
@@ -99,8 +99,37 @@ LL -     loop { if (break ({ println!("hello") })) {} }
 LL +     loop { if break ({ println!("hello") }) {} }
    |
 
+error: unnecessary parentheses around `break` value
+  --> $DIR/issue-54538-unused-parens-lint.rs:46:22
+   |
+LL |     loop { if (break ({ println!("hello") })) {} }
+   |                      ^                     ^
+   |
+help: remove these parentheses
+   |
+LL -     loop { if (break ({ println!("hello") })) {} }
+LL +     loop { if (break { println!("hello") }) {} }
+   |
+
+error: unnecessary braces around `break` value
+  --> $DIR/issue-54538-unused-parens-lint.rs:49:22
+   |
+LL |     loop { if (break { println!("hello") }) {} }
+   |                      ^^                 ^^
+   |
+note: the lint level is defined here
+  --> $DIR/issue-54538-unused-parens-lint.rs:13:24
+   |
+LL | #![deny(unused_parens, unused_braces)]
+   |                        ^^^^^^^^^^^^^
+help: remove these braces
+   |
+LL -     loop { if (break { println!("hello") }) {} }
+LL +     loop { if (break println!("hello")) {} }
+   |
+
 error: unnecessary parentheses around pattern
-  --> $DIR/issue-54538-unused-parens-lint.rs:71:12
+  --> $DIR/issue-54538-unused-parens-lint.rs:73:12
    |
 LL |     if let (0 | 1) = 0 {}
    |            ^     ^
@@ -112,7 +141,7 @@ LL +     if let 0 | 1 = 0 {}
    |
 
 error: unnecessary parentheses around pattern
-  --> $DIR/issue-54538-unused-parens-lint.rs:72:13
+  --> $DIR/issue-54538-unused-parens-lint.rs:74:13
    |
 LL |     if let ((0 | 1),) = (0,) {}
    |             ^     ^
@@ -124,7 +153,7 @@ LL +     if let (0 | 1,) = (0,) {}
    |
 
 error: unnecessary parentheses around pattern
-  --> $DIR/issue-54538-unused-parens-lint.rs:73:13
+  --> $DIR/issue-54538-unused-parens-lint.rs:75:13
    |
 LL |     if let [(0 | 1)] = [0] {}
    |             ^     ^
@@ -136,7 +165,7 @@ LL +     if let [0 | 1] = [0] {}
    |
 
 error: unnecessary parentheses around pattern
-  --> $DIR/issue-54538-unused-parens-lint.rs:74:16
+  --> $DIR/issue-54538-unused-parens-lint.rs:76:16
    |
 LL |     if let 0 | (1 | 2) = 0 {}
    |                ^     ^
@@ -148,7 +177,7 @@ LL +     if let 0 | 1 | 2 = 0 {}
    |
 
 error: unnecessary parentheses around pattern
-  --> $DIR/issue-54538-unused-parens-lint.rs:76:15
+  --> $DIR/issue-54538-unused-parens-lint.rs:78:15
    |
 LL |     if let TS((0 | 1)) = TS(0) {}
    |               ^     ^
@@ -160,7 +189,7 @@ LL +     if let TS(0 | 1) = TS(0) {}
    |
 
 error: unnecessary parentheses around pattern
-  --> $DIR/issue-54538-unused-parens-lint.rs:78:20
+  --> $DIR/issue-54538-unused-parens-lint.rs:80:20
    |
 LL |     if let NS { f: (0 | 1) } = (NS { f: 0 }) {}
    |                    ^     ^
@@ -172,7 +201,7 @@ LL +     if let NS { f: 0 | 1 } = (NS { f: 0 }) {}
    |
 
 error: unnecessary parentheses around pattern
-  --> $DIR/issue-54538-unused-parens-lint.rs:88:9
+  --> $DIR/issue-54538-unused-parens-lint.rs:90:9
    |
 LL |         (_) => {}
    |         ^ ^
@@ -184,7 +213,7 @@ LL +         _ => {}
    |
 
 error: unnecessary parentheses around pattern
-  --> $DIR/issue-54538-unused-parens-lint.rs:89:9
+  --> $DIR/issue-54538-unused-parens-lint.rs:91:9
    |
 LL |         (y) => {}
    |         ^ ^
@@ -196,7 +225,7 @@ LL +         y => {}
    |
 
 error: unnecessary parentheses around pattern
-  --> $DIR/issue-54538-unused-parens-lint.rs:90:9
+  --> $DIR/issue-54538-unused-parens-lint.rs:92:9
    |
 LL |         (ref r) => {}
    |         ^     ^
@@ -208,7 +237,7 @@ LL +         ref r => {}
    |
 
 error: unnecessary parentheses around pattern
-  --> $DIR/issue-54538-unused-parens-lint.rs:91:9
+  --> $DIR/issue-54538-unused-parens-lint.rs:93:9
    |
 LL |         (e @ 1...2) => {}
    |         ^         ^
@@ -220,7 +249,7 @@ LL +         e @ 1...2 => {}
    |
 
 error: unnecessary parentheses around pattern
-  --> $DIR/issue-54538-unused-parens-lint.rs:97:9
+  --> $DIR/issue-54538-unused-parens-lint.rs:99:9
    |
 LL |         (e @ &(1...2)) => {}
    |         ^            ^
@@ -232,7 +261,7 @@ LL +         e @ &(1...2) => {}
    |
 
 error: unnecessary parentheses around pattern
-  --> $DIR/issue-54538-unused-parens-lint.rs:98:10
+  --> $DIR/issue-54538-unused-parens-lint.rs:100:10
    |
 LL |         &(_) => {}
    |          ^ ^
@@ -244,7 +273,7 @@ LL +         &_ => {}
    |
 
 error: unnecessary parentheses around pattern
-  --> $DIR/issue-54538-unused-parens-lint.rs:109:9
+  --> $DIR/issue-54538-unused-parens-lint.rs:111:9
    |
 LL |         (_) => {}
    |         ^ ^
@@ -256,7 +285,7 @@ LL +         _ => {}
    |
 
 error: unnecessary parentheses around pattern
-  --> $DIR/issue-54538-unused-parens-lint.rs:110:9
+  --> $DIR/issue-54538-unused-parens-lint.rs:112:9
    |
 LL |         (y) => {}
    |         ^ ^
@@ -268,7 +297,7 @@ LL +         y => {}
    |
 
 error: unnecessary parentheses around pattern
-  --> $DIR/issue-54538-unused-parens-lint.rs:111:9
+  --> $DIR/issue-54538-unused-parens-lint.rs:113:9
    |
 LL |         (ref r) => {}
    |         ^     ^
@@ -280,7 +309,7 @@ LL +         ref r => {}
    |
 
 error: unnecessary parentheses around pattern
-  --> $DIR/issue-54538-unused-parens-lint.rs:112:9
+  --> $DIR/issue-54538-unused-parens-lint.rs:114:9
    |
 LL |         (e @ 1..=2) => {}
    |         ^         ^
@@ -292,7 +321,7 @@ LL +         e @ 1..=2 => {}
    |
 
 error: unnecessary parentheses around pattern
-  --> $DIR/issue-54538-unused-parens-lint.rs:118:9
+  --> $DIR/issue-54538-unused-parens-lint.rs:120:9
    |
 LL |         (e @ &(1..=2)) => {}
    |         ^            ^
@@ -304,7 +333,7 @@ LL +         e @ &(1..=2) => {}
    |
 
 error: unnecessary parentheses around pattern
-  --> $DIR/issue-54538-unused-parens-lint.rs:119:10
+  --> $DIR/issue-54538-unused-parens-lint.rs:121:10
    |
 LL |         &(_) => {}
    |          ^ ^
@@ -315,5 +344,5 @@ LL -         &(_) => {}
 LL +         &_ => {}
    |
 
-error: aborting due to 26 previous errors
+error: aborting due to 28 previous errors
 

tests/ui/lint/unused/unused-parens-assign-expr-in-ret-issue-131989.fixed

@@ -0,0 +1,32 @@
+//@ run-rustfix
+#![deny(unused_parens)]
+#![allow(unreachable_code)]
+
+fn foo() {
+    loop {
+        break (_ = 42);
+        // lint unused_parens should not be triggered here.
+    }
+
+    let _ = loop {
+        let a = 1;
+        let b = 2;
+        break a + b; //~ERROR unnecessary parentheses
+    };
+
+    loop {
+        if break return () {
+            //~^ ERROR unnecessary parentheses
+        }
+        if break return () {
+            //~^ ERROR unnecessary parentheses
+        }
+    }
+
+    return (_ = 42);
+    // lint unused_parens should not be triggered here.
+}
+
+fn main() {
+    let _ = foo();
+}

tests/ui/lint/unused/unused-parens-assign-expr-in-ret-issue-131989.rs

@@ -0,0 +1,32 @@
+//@ run-rustfix
+#![deny(unused_parens)]
+#![allow(unreachable_code)]
+
+fn foo() {
+    loop {
+        break (_ = 42);
+        // lint unused_parens should not be triggered here.
+    }
+
+    let _ = loop {
+        let a = 1;
+        let b = 2;
+        break (a + b); //~ERROR unnecessary parentheses
+    };
+
+    loop {
+        if (break return ()) {
+            //~^ ERROR unnecessary parentheses
+        }
+        if break (return ()) {
+            //~^ ERROR unnecessary parentheses
+        }
+    }
+
+    return (_ = 42);
+    // lint unused_parens should not be triggered here.
+}
+
+fn main() {
+    let _ = foo();
+}

tests/ui/lint/unused/unused-parens-assign-expr-in-ret-issue-131989.stderr

@@ -0,0 +1,43 @@
+error: unnecessary parentheses around `break` value
+  --> $DIR/unused-parens-assign-expr-in-ret-issue-131989.rs:14:15
+   |
+LL |         break (a + b);
+   |               ^     ^
+   |
+note: the lint level is defined here
+  --> $DIR/unused-parens-assign-expr-in-ret-issue-131989.rs:2:9
+   |
+LL | #![deny(unused_parens)]
+   |         ^^^^^^^^^^^^^
+help: remove these parentheses
+   |
+LL -         break (a + b);
+LL +         break a + b;
+   |
+
+error: unnecessary parentheses around `if` condition
+  --> $DIR/unused-parens-assign-expr-in-ret-issue-131989.rs:18:12
+   |
+LL |         if (break return ()) {
+   |            ^               ^
+   |
+help: remove these parentheses
+   |
+LL -         if (break return ()) {
+LL +         if break return () {
+   |
+
+error: unnecessary parentheses around `break` value
+  --> $DIR/unused-parens-assign-expr-in-ret-issue-131989.rs:21:18
+   |
+LL |         if break (return ()) {
+   |                  ^         ^
+   |
+help: remove these parentheses
+   |
+LL -         if break (return ()) {
+LL +         if break return () {
+   |
+
+error: aborting due to 3 previous errors
+

tests/ui/lint/unused_parens_json_suggestion.fixed

@@ -9,7 +9,7 @@
 // test of the JSON error format.
 
 #![deny(unused_parens)]
-#![allow(unreachable_code)]
+#![allow(unreachable_code, unused_braces)]
 
 fn main() {
     // We want to suggest the properly-balanced expression `1 / (2 + 3)`, not

tests/ui/lint/unused_parens_json_suggestion.rs

@@ -9,7 +9,7 @@
 // test of the JSON error format.
 
 #![deny(unused_parens)]
-#![allow(unreachable_code)]
+#![allow(unreachable_code, unused_braces)]
 
 fn main() {
     // We want to suggest the properly-balanced expression `1 / (2 + 3)`, not

tests/ui/lint/unused_parens_json_suggestion.stderr

@@ -1,4 +1,4 @@
-{"$message_type":"diagnostic","message":"unnecessary parentheses around assigned value","code":{"code":"unused_parens","explanation":null},"level":"error","spans":[{"file_name":"$DIR/unused_parens_json_suggestion.rs","byte_start":621,"byte_end":622,"line_start":17,"line_end":17,"column_start":14,"column_end":15,"is_primary":true,"text":[{"text":"    let _a = (1 / (2 + 3));","highlight_start":14,"highlight_end":15}],"label":null,"suggested_replacement":null,"suggestion_applicability":null,"expansion":null},{"file_name":"$DIR/unused_parens_json_suggestion.rs","byte_start":633,"byte_end":634,"line_start":17,"line_end":17,"column_start":26,"column_end":27,"is_primary":true,"text":[{"text":"    let _a = (1 / (2 + 3));","highlight_start":26,"highlight_end":27}],"label":null,"suggested_replacement":null,"suggestion_applicability":null,"expansion":null}],"children":[{"message":"the lint level is defined here","code":null,"level":"note","spans":[{"file_name":"$DIR/unused_parens_json_suggestion.rs","byte_start":439,"byte_end":452,"line_start":11,"line_end":11,"column_start":9,"column_end":22,"is_primary":true,"text":[{"text":"#![deny(unused_parens)]","highlight_start":9,"highlight_end":22}],"label":null,"suggested_replacement":null,"suggestion_applicability":null,"expansion":null}],"children":[],"rendered":null},{"message":"remove these parentheses","code":null,"level":"help","spans":[{"file_name":"$DIR/unused_parens_json_suggestion.rs","byte_start":621,"byte_end":622,"line_start":17,"line_end":17,"column_start":14,"column_end":15,"is_primary":true,"text":[{"text":"    let _a = (1 / (2 + 3));","highlight_start":14,"highlight_end":15}],"label":null,"suggested_replacement":"","suggestion_applicability":"MachineApplicable","expansion":null},{"file_name":"$DIR/unused_parens_json_suggestion.rs","byte_start":633,"byte_end":634,"line_start":17,"line_end":17,"column_start":26,"column_end":27,"is_primary":true,"text":[{"text":"    let _a = (1 / (2 + 3));","highlight_start":26,"highlight_end":27}],"label":null,"suggested_replacement":"","suggestion_applicability":"MachineApplicable","expansion":null}],"children":[],"rendered":null}],"rendered":"error: unnecessary parentheses around assigned value
+{"$message_type":"diagnostic","message":"unnecessary parentheses around assigned value","code":{"code":"unused_parens","explanation":null},"level":"error","spans":[{"file_name":"$DIR/unused_parens_json_suggestion.rs","byte_start":636,"byte_end":637,"line_start":17,"line_end":17,"column_start":14,"column_end":15,"is_primary":true,"text":[{"text":"    let _a = (1 / (2 + 3));","highlight_start":14,"highlight_end":15}],"label":null,"suggested_replacement":null,"suggestion_applicability":null,"expansion":null},{"file_name":"$DIR/unused_parens_json_suggestion.rs","byte_start":648,"byte_end":649,"line_start":17,"line_end":17,"column_start":26,"column_end":27,"is_primary":true,"text":[{"text":"    let _a = (1 / (2 + 3));","highlight_start":26,"highlight_end":27}],"label":null,"suggested_replacement":null,"suggestion_applicability":null,"expansion":null}],"children":[{"message":"the lint level is defined here","code":null,"level":"note","spans":[{"file_name":"$DIR/unused_parens_json_suggestion.rs","byte_start":439,"byte_end":452,"line_start":11,"line_end":11,"column_start":9,"column_end":22,"is_primary":true,"text":[{"text":"#![deny(unused_parens)]","highlight_start":9,"highlight_end":22}],"label":null,"suggested_replacement":null,"suggestion_applicability":null,"expansion":null}],"children":[],"rendered":null},{"message":"remove these parentheses","code":null,"level":"help","spans":[{"file_name":"$DIR/unused_parens_json_suggestion.rs","byte_start":636,"byte_end":637,"line_start":17,"line_end":17,"column_start":14,"column_end":15,"is_primary":true,"text":[{"text":"    let _a = (1 / (2 + 3));","highlight_start":14,"highlight_end":15}],"label":null,"suggested_replacement":"","suggestion_applicability":"MachineApplicable","expansion":null},{"file_name":"$DIR/unused_parens_json_suggestion.rs","byte_start":648,"byte_end":649,"line_start":17,"line_end":17,"column_start":26,"column_end":27,"is_primary":true,"text":[{"text":"    let _a = (1 / (2 + 3));","highlight_start":26,"highlight_end":27}],"label":null,"suggested_replacement":"","suggestion_applicability":"MachineApplicable","expansion":null}],"children":[],"rendered":null}],"rendered":"error: unnecessary parentheses around assigned value
   --> $DIR/unused_parens_json_suggestion.rs:17:14
    |
 LL |     let _a = (1 / (2 + 3));

tests/ui/lint/unused_parens_remove_json_suggestion.fixed

@@ -9,7 +9,7 @@
 // test of the JSON error format.
 
 #![deny(unused_parens)]
-#![allow(unreachable_code)]
+#![allow(unreachable_code, unused_braces)]
 
 fn main() {
 

tests/ui/lint/unused_parens_remove_json_suggestion.rs

@@ -9,7 +9,7 @@
 // test of the JSON error format.
 
 #![deny(unused_parens)]
-#![allow(unreachable_code)]
+#![allow(unreachable_code, unused_braces)]
 
 fn main() {
 

tests/ui/never_type/defaulted-never-note.nofallback.stderr

@@ -4,7 +4,7 @@ warning: this function depends on never type fallback being `()`
 LL | fn smeg() {
    | ^^^^^^^^^
    |
-   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in Rust 2024 and in a future release in all editions!
    = note: for more information, see issue #123748 <https://github.com/rust-lang/rust/issues/123748>
    = help: specify the types explicitly
 note: in edition 2024, the requirement `!: ImplementedForUnitButNotNever` will fail

tests/ui/never_type/defaulted-never-note.rs

@@ -27,7 +27,7 @@ fn foo<T: ImplementedForUnitButNotNever>(_t: T) {}
 //[fallback]~| NOTE required by a bound in `foo`
 fn smeg() {
     //[nofallback]~^ warn: this function depends on never type fallback being `()`
-    //[nofallback]~| warn: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+    //[nofallback]~| warn: this was previously accepted by the compiler but is being phased out; it will become a hard error in Rust 2024 and in a future release in all editions!
     let _x = return;
     foo(_x);
     //[fallback]~^ ERROR the trait bound

tests/ui/never_type/dependency-on-fallback-to-unit.rs

@@ -7,7 +7,7 @@ fn main() {
 
 fn def() {
     //~^ warn: this function depends on never type fallback being `()`
-    //~| warn: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+    //~| warn: this was previously accepted by the compiler but is being phased out; it will become a hard error in Rust 2024 and in a future release in all editions!
     match true {
         false => <_>::default(),
         true => return,
@@ -18,7 +18,7 @@ fn def() {
 // <https://github.com/rust-lang/rust/issues/39216>
 fn question_mark() -> Result<(), ()> {
     //~^ warn: this function depends on never type fallback being `()`
-    //~| warn: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+    //~| warn: this was previously accepted by the compiler but is being phased out; it will become a hard error in Rust 2024 and in a future release in all editions!
     deserialize()?;
     Ok(())
 }

tests/ui/never_type/dependency-on-fallback-to-unit.stderr

@@ -4,7 +4,7 @@ warning: this function depends on never type fallback being `()`
 LL | fn def() {
    | ^^^^^^^^
    |
-   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in Rust 2024 and in a future release in all editions!
    = note: for more information, see issue #123748 <https://github.com/rust-lang/rust/issues/123748>
    = help: specify the types explicitly
 note: in edition 2024, the requirement `!: Default` will fail
@@ -24,7 +24,7 @@ warning: this function depends on never type fallback being `()`
 LL | fn question_mark() -> Result<(), ()> {
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
-   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in Rust 2024 and in a future release in all editions!
    = note: for more information, see issue #123748 <https://github.com/rust-lang/rust/issues/123748>
    = help: specify the types explicitly
 note: in edition 2024, the requirement `!: Default` will fail

tests/ui/never_type/diverging-fallback-control-flow.nofallback.stderr

@@ -4,7 +4,7 @@ warning: this function depends on never type fallback being `()`
 LL | fn assignment() {
    | ^^^^^^^^^^^^^^^
    |
-   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in Rust 2024 and in a future release in all editions!
    = note: for more information, see issue #123748 <https://github.com/rust-lang/rust/issues/123748>
    = help: specify the types explicitly
 note: in edition 2024, the requirement `!: UnitDefault` will fail
@@ -24,7 +24,7 @@ warning: this function depends on never type fallback being `()`
 LL | fn assignment_rev() {
    | ^^^^^^^^^^^^^^^^^^^
    |
-   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in Rust 2024 and in a future release in all editions!
    = note: for more information, see issue #123748 <https://github.com/rust-lang/rust/issues/123748>
    = help: specify the types explicitly
 note: in edition 2024, the requirement `!: UnitDefault` will fail

tests/ui/never_type/diverging-fallback-control-flow.rs

@@ -29,7 +29,7 @@ impl UnitDefault for () {
 
 fn assignment() {
     //[nofallback]~^ warn: this function depends on never type fallback being `()`
-    //[nofallback]~| warn: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+    //[nofallback]~| warn: this was previously accepted by the compiler but is being phased out; it will become a hard error in Rust 2024 and in a future release in all editions!
     let x;
 
     if true {
@@ -41,7 +41,7 @@ fn assignment() {
 
 fn assignment_rev() {
     //[nofallback]~^ warn: this function depends on never type fallback being `()`
-    //[nofallback]~| warn: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+    //[nofallback]~| warn: this was previously accepted by the compiler but is being phased out; it will become a hard error in Rust 2024 and in a future release in all editions!
     let x;
 
     if true {

tests/ui/never_type/diverging-fallback-no-leak.nofallback.stderr

@@ -4,7 +4,7 @@ warning: this function depends on never type fallback being `()`
 LL | fn main() {
    | ^^^^^^^^^
    |
-   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in Rust 2024 and in a future release in all editions!
    = note: for more information, see issue #123748 <https://github.com/rust-lang/rust/issues/123748>
    = help: specify the types explicitly
 note: in edition 2024, the requirement `!: Test` will fail

tests/ui/never_type/diverging-fallback-no-leak.rs

@@ -13,7 +13,7 @@ fn unconstrained_arg<T: Test>(_: T) {}
 
 fn main() {
     //[nofallback]~^ warn: this function depends on never type fallback being `()`
-    //[nofallback]~| warn: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+    //[nofallback]~| warn: this was previously accepted by the compiler but is being phased out; it will become a hard error in Rust 2024 and in a future release in all editions!
 
     // Here the type variable falls back to `!`,
     // and hence we get a type error.

tests/ui/never_type/diverging-fallback-unconstrained-return.nofallback.stderr

@@ -4,7 +4,7 @@ warning: this function depends on never type fallback being `()`
 LL | fn main() {
    | ^^^^^^^^^
    |
-   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in Rust 2024 and in a future release in all editions!
    = note: for more information, see issue #123748 <https://github.com/rust-lang/rust/issues/123748>
    = help: specify the types explicitly
 note: in edition 2024, the requirement `!: UnitReturn` will fail

tests/ui/never_type/diverging-fallback-unconstrained-return.rs

@@ -27,7 +27,7 @@ fn unconstrained_return<T: UnitReturn>() -> T {
 
 fn main() {
     //[nofallback]~^ warn: this function depends on never type fallback being `()`
-    //[nofallback]~| warn: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+    //[nofallback]~| warn: this was previously accepted by the compiler but is being phased out; it will become a hard error in Rust 2024 and in a future release in all editions!
 
     // In Ye Olde Days, the `T` parameter of `unconstrained_return`
     // winds up "entangled" with the `!` type that results from

tests/ui/never_type/fallback-closure-ret.nofallback.stderr

@@ -4,7 +4,7 @@ warning: this function depends on never type fallback being `()`
 LL | fn main() {
    | ^^^^^^^^^
    |
-   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in Rust 2024 and in a future release in all editions!
    = note: for more information, see issue #123748 <https://github.com/rust-lang/rust/issues/123748>
    = help: specify the types explicitly
 note: in edition 2024, the requirement `!: Bar` will fail

tests/ui/never_type/fallback-closure-ret.rs

@@ -20,6 +20,6 @@ fn foo<R: Bar>(_: impl Fn() -> R) {}
 
 fn main() {
     //[nofallback]~^ warn: this function depends on never type fallback being `()`
-    //[nofallback]~| warn: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+    //[nofallback]~| warn: this was previously accepted by the compiler but is being phased out; it will become a hard error in Rust 2024 and in a future release in all editions!
     foo(|| panic!());
 }

tests/ui/never_type/impl_trait_fallback.rs

@@ -7,6 +7,6 @@ impl T for () {}
 
 fn should_ret_unit() -> impl T {
     //~^ warn: this function depends on never type fallback being `()`
-    //~| warn: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+    //~| warn: this was previously accepted by the compiler but is being phased out; it will become a hard error in Rust 2024 and in a future release in all editions!
     panic!()
 }

tests/ui/never_type/impl_trait_fallback.stderr

@@ -4,7 +4,7 @@ warning: this function depends on never type fallback being `()`
 LL | fn should_ret_unit() -> impl T {
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
-   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in Rust 2024 and in a future release in all editions!
    = note: for more information, see issue #123748 <https://github.com/rust-lang/rust/issues/123748>
    = help: specify the types explicitly
 note: in edition 2024, the requirement `!: T` will fail

tests/ui/never_type/lint-never-type-fallback-flowing-into-unsafe.e2015.stderr

@@ -4,7 +4,7 @@ warning: never type fallback affects this call to an `unsafe` function
 LL |         unsafe { mem::zeroed() }
    |                  ^^^^^^^^^^^^^
    |
-   = warning: this will change its meaning in a future release!
+   = warning: this changes meaning in Rust 2024 and in a future release in all editions!
    = note: for more information, see issue #123748 <https://github.com/rust-lang/rust/issues/123748>
    = help: specify the type explicitly
    = note: `#[warn(never_type_fallback_flowing_into_unsafe)]` on by default
@@ -19,7 +19,7 @@ warning: never type fallback affects this call to an `unsafe` function
 LL |             core::mem::transmute(Zst)
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^
    |
-   = warning: this will change its meaning in a future release!
+   = warning: this changes meaning in Rust 2024 and in a future release in all editions!
    = note: for more information, see issue #123748 <https://github.com/rust-lang/rust/issues/123748>
    = help: specify the type explicitly
 help: use `()` annotations to avoid fallback changes
@@ -33,7 +33,7 @@ warning: never type fallback affects this union access
 LL |         unsafe { Union { a: () }.b }
    |                  ^^^^^^^^^^^^^^^^^
    |
-   = warning: this will change its meaning in a future release!
+   = warning: this changes meaning in Rust 2024 and in a future release in all editions!
    = note: for more information, see issue #123748 <https://github.com/rust-lang/rust/issues/123748>
    = help: specify the type explicitly
 
@@ -43,7 +43,7 @@ warning: never type fallback affects this raw pointer dereference
 LL |         unsafe { *ptr::from_ref(&()).cast() }
    |                  ^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
-   = warning: this will change its meaning in a future release!
+   = warning: this changes meaning in Rust 2024 and in a future release in all editions!
    = note: for more information, see issue #123748 <https://github.com/rust-lang/rust/issues/123748>
    = help: specify the type explicitly
 help: use `()` annotations to avoid fallback changes
@@ -57,7 +57,7 @@ warning: never type fallback affects this call to an `unsafe` function
 LL |         unsafe { internally_create(x) }
    |                  ^^^^^^^^^^^^^^^^^^^^
    |
-   = warning: this will change its meaning in a future release!
+   = warning: this changes meaning in Rust 2024 and in a future release in all editions!
    = note: for more information, see issue #123748 <https://github.com/rust-lang/rust/issues/123748>
    = help: specify the type explicitly
 help: use `()` annotations to avoid fallback changes
@@ -71,7 +71,7 @@ warning: never type fallback affects this call to an `unsafe` function
 LL |         unsafe { zeroed() }
    |                  ^^^^^^^^
    |
-   = warning: this will change its meaning in a future release!
+   = warning: this changes meaning in Rust 2024 and in a future release in all editions!
    = note: for more information, see issue #123748 <https://github.com/rust-lang/rust/issues/123748>
    = help: specify the type explicitly
 help: use `()` annotations to avoid fallback changes
@@ -85,7 +85,7 @@ warning: never type fallback affects this `unsafe` function
 LL |         let zeroed = mem::zeroed;
    |                      ^^^^^^^^^^^
    |
-   = warning: this will change its meaning in a future release!
+   = warning: this changes meaning in Rust 2024 and in a future release in all editions!
    = note: for more information, see issue #123748 <https://github.com/rust-lang/rust/issues/123748>
    = help: specify the type explicitly
 help: use `()` annotations to avoid fallback changes
@@ -99,7 +99,7 @@ warning: never type fallback affects this `unsafe` function
 LL |         let f = internally_create;
    |                 ^^^^^^^^^^^^^^^^^
    |
-   = warning: this will change its meaning in a future release!
+   = warning: this changes meaning in Rust 2024 and in a future release in all editions!
    = note: for more information, see issue #123748 <https://github.com/rust-lang/rust/issues/123748>
    = help: specify the type explicitly
 help: use `()` annotations to avoid fallback changes
@@ -113,7 +113,7 @@ warning: never type fallback affects this call to an `unsafe` method
 LL |             S(marker::PhantomData).create_out_of_thin_air()
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
-   = warning: this will change its meaning in a future release!
+   = warning: this changes meaning in Rust 2024 and in a future release in all editions!
    = note: for more information, see issue #123748 <https://github.com/rust-lang/rust/issues/123748>
    = help: specify the type explicitly
 
@@ -126,7 +126,7 @@ LL |             match send_message::<_ /* ?0 */>() {
 LL |         msg_send!();
    |         ----------- in this macro invocation
    |
-   = warning: this will change its meaning in a future release!
+   = warning: this changes meaning in Rust 2024 and in a future release in all editions!
    = note: for more information, see issue #123748 <https://github.com/rust-lang/rust/issues/123748>
    = help: specify the type explicitly
    = note: this warning originates in the macro `msg_send` (in Nightly builds, run with -Z macro-backtrace for more info)

tests/ui/never_type/lint-never-type-fallback-flowing-into-unsafe.e2024.stderr

@@ -4,7 +4,7 @@ error: never type fallback affects this call to an `unsafe` function
 LL |         unsafe { mem::zeroed() }
    |                  ^^^^^^^^^^^^^
    |
-   = warning: this will change its meaning in a future release!
+   = warning: this changes meaning in Rust 2024 and in a future release in all editions!
    = note: for more information, see issue #123748 <https://github.com/rust-lang/rust/issues/123748>
    = help: specify the type explicitly
    = note: `#[deny(never_type_fallback_flowing_into_unsafe)]` on by default
@@ -19,7 +19,7 @@ error: never type fallback affects this call to an `unsafe` function
 LL |             core::mem::transmute(Zst)
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^
    |
-   = warning: this will change its meaning in a future release!
+   = warning: this changes meaning in Rust 2024 and in a future release in all editions!
    = note: for more information, see issue #123748 <https://github.com/rust-lang/rust/issues/123748>
    = help: specify the type explicitly
 help: use `()` annotations to avoid fallback changes
@@ -33,7 +33,7 @@ error: never type fallback affects this union access
 LL |         unsafe { Union { a: () }.b }
    |                  ^^^^^^^^^^^^^^^^^
    |
-   = warning: this will change its meaning in a future release!
+   = warning: this changes meaning in Rust 2024 and in a future release in all editions!
    = note: for more information, see issue #123748 <https://github.com/rust-lang/rust/issues/123748>
    = help: specify the type explicitly
 
@@ -43,7 +43,7 @@ error: never type fallback affects this raw pointer dereference
 LL |         unsafe { *ptr::from_ref(&()).cast() }
    |                  ^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
-   = warning: this will change its meaning in a future release!
+   = warning: this changes meaning in Rust 2024 and in a future release in all editions!
    = note: for more information, see issue #123748 <https://github.com/rust-lang/rust/issues/123748>
    = help: specify the type explicitly
 help: use `()` annotations to avoid fallback changes
@@ -57,7 +57,7 @@ error: never type fallback affects this call to an `unsafe` function
 LL |         unsafe { internally_create(x) }
    |                  ^^^^^^^^^^^^^^^^^^^^
    |
-   = warning: this will change its meaning in a future release!
+   = warning: this changes meaning in Rust 2024 and in a future release in all editions!
    = note: for more information, see issue #123748 <https://github.com/rust-lang/rust/issues/123748>
    = help: specify the type explicitly
 help: use `()` annotations to avoid fallback changes
@@ -71,7 +71,7 @@ error: never type fallback affects this call to an `unsafe` function
 LL |         unsafe { zeroed() }
    |                  ^^^^^^^^
    |
-   = warning: this will change its meaning in a future release!
+   = warning: this changes meaning in Rust 2024 and in a future release in all editions!
    = note: for more information, see issue #123748 <https://github.com/rust-lang/rust/issues/123748>
    = help: specify the type explicitly
 help: use `()` annotations to avoid fallback changes
@@ -85,7 +85,7 @@ error: never type fallback affects this `unsafe` function
 LL |         let zeroed = mem::zeroed;
    |                      ^^^^^^^^^^^
    |
-   = warning: this will change its meaning in a future release!
+   = warning: this changes meaning in Rust 2024 and in a future release in all editions!
    = note: for more information, see issue #123748 <https://github.com/rust-lang/rust/issues/123748>
    = help: specify the type explicitly
 help: use `()` annotations to avoid fallback changes
@@ -99,7 +99,7 @@ error: never type fallback affects this `unsafe` function
 LL |         let f = internally_create;
    |                 ^^^^^^^^^^^^^^^^^
    |
-   = warning: this will change its meaning in a future release!
+   = warning: this changes meaning in Rust 2024 and in a future release in all editions!
    = note: for more information, see issue #123748 <https://github.com/rust-lang/rust/issues/123748>
    = help: specify the type explicitly
 help: use `()` annotations to avoid fallback changes
@@ -113,7 +113,7 @@ error: never type fallback affects this call to an `unsafe` method
 LL |             S(marker::PhantomData).create_out_of_thin_air()
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
-   = warning: this will change its meaning in a future release!
+   = warning: this changes meaning in Rust 2024 and in a future release in all editions!
    = note: for more information, see issue #123748 <https://github.com/rust-lang/rust/issues/123748>
    = help: specify the type explicitly
 
@@ -126,7 +126,7 @@ LL |             match send_message::<_ /* ?0 */>() {
 LL |         msg_send!();
    |         ----------- in this macro invocation
    |
-   = warning: this will change its meaning in a future release!
+   = warning: this changes meaning in Rust 2024 and in a future release in all editions!
    = note: for more information, see issue #123748 <https://github.com/rust-lang/rust/issues/123748>
    = help: specify the type explicitly
    = note: this error originates in the macro `msg_send` (in Nightly builds, run with -Z macro-backtrace for more info)

tests/ui/never_type/lint-never-type-fallback-flowing-into-unsafe.rs

@@ -13,7 +13,7 @@ fn _zero() {
         unsafe { mem::zeroed() }
         //[e2015]~^ warn: never type fallback affects this call to an `unsafe` function
         //[e2024]~^^ error: never type fallback affects this call to an `unsafe` function
-        //~| warn: this will change its meaning in a future release!
+        //~| warn: this changes meaning in Rust 2024 and in a future release in all editions!
         //[e2024]~| warning: the type `!` does not permit zero-initialization
     } else {
         return;
@@ -30,7 +30,7 @@ fn _trans() {
             core::mem::transmute(Zst)
             //[e2015]~^ warn: never type fallback affects this call to an `unsafe` function
             //[e2024]~^^ error: never type fallback affects this call to an `unsafe` function
-            //~| warn: this will change its meaning in a future release!
+            //~| warn: this changes meaning in Rust 2024 and in a future release in all editions!
         }
     } else {
         return;
@@ -47,7 +47,7 @@ fn _union() {
         unsafe { Union { a: () }.b }
         //[e2015]~^ warn: never type fallback affects this union access
         //[e2024]~^^ error: never type fallback affects this union access
-        //~| warn: this will change its meaning in a future release!
+        //~| warn: this changes meaning in Rust 2024 and in a future release in all editions!
     } else {
         return;
     };
@@ -58,7 +58,7 @@ fn _deref() {
         unsafe { *ptr::from_ref(&()).cast() }
         //[e2015]~^ warn: never type fallback affects this raw pointer dereference
         //[e2024]~^^ error: never type fallback affects this raw pointer dereference
-        //~| warn: this will change its meaning in a future release!
+        //~| warn: this changes meaning in Rust 2024 and in a future release in all editions!
     } else {
         return;
     };
@@ -79,7 +79,7 @@ fn _only_generics() {
         unsafe { internally_create(x) }
         //[e2015]~^ warn: never type fallback affects this call to an `unsafe` function
         //[e2024]~^^ error: never type fallback affects this call to an `unsafe` function
-        //~| warn: this will change its meaning in a future release!
+        //~| warn: this changes meaning in Rust 2024 and in a future release in all editions!
 
         x.unwrap()
     } else {
@@ -92,12 +92,12 @@ fn _stored_function() {
         let zeroed = mem::zeroed;
         //[e2015]~^ warn: never type fallback affects this `unsafe` function
         //[e2024]~^^ error: never type fallback affects this `unsafe` function
-        //~| warn: this will change its meaning in a future release!
+        //~| warn: this changes meaning in Rust 2024 and in a future release in all editions!
 
         unsafe { zeroed() }
         //[e2015]~^ warn: never type fallback affects this call to an `unsafe` function
         //[e2024]~^^ error: never type fallback affects this call to an `unsafe` function
-        //~| warn: this will change its meaning in a future release!
+        //~| warn: this changes meaning in Rust 2024 and in a future release in all editions!
     } else {
         return;
     };
@@ -115,7 +115,7 @@ fn _only_generics_stored_function() {
         let f = internally_create;
         //[e2015]~^ warn: never type fallback affects this `unsafe` function
         //[e2024]~^^ error: never type fallback affects this `unsafe` function
-        //~| warn: this will change its meaning in a future release!
+        //~| warn: this changes meaning in Rust 2024 and in a future release in all editions!
 
         unsafe { f(x) }
 
@@ -140,7 +140,7 @@ fn _method() {
             S(marker::PhantomData).create_out_of_thin_air()
             //[e2015]~^ warn: never type fallback affects this call to an `unsafe` method
             //[e2024]~^^ error: never type fallback affects this call to an `unsafe` method
-            //~| warn: this will change its meaning in a future release!
+            //~| warn: this changes meaning in Rust 2024 and in a future release in all editions!
         }
     } else {
         return;
@@ -158,7 +158,7 @@ fn _objc() {
             match send_message::<_ /* ?0 */>() {
                 //[e2015]~^ warn: never type fallback affects this call to an `unsafe` function
                 //[e2024]~^^ error: never type fallback affects this call to an `unsafe` function
-                //~| warn: this will change its meaning in a future release!
+                //~| warn: this changes meaning in Rust 2024 and in a future release in all editions!
                 Ok(x) => x,
                 Err(_) => loop {},
             }

tests/ui/structs-enums/enum-rec/issue-17431-6.rs

@@ -1,8 +1,6 @@
-//@ ignore-apple: cycle error does not appear on apple
+use std::cell::UnsafeCell;
 
-use std::sync::Mutex;
-
-enum Foo { X(Mutex<Option<Foo>>) }
+enum Foo { X(UnsafeCell<Option<Foo>>) }
 //~^ ERROR recursive type `Foo` has infinite size
 //~| ERROR cycle detected
 

tests/ui/structs-enums/enum-rec/issue-17431-6.stderr

@@ -1,18 +1,18 @@
 error[E0072]: recursive type `Foo` has infinite size
-  --> $DIR/issue-17431-6.rs:5:1
+  --> $DIR/issue-17431-6.rs:3:1
    |
-LL | enum Foo { X(Mutex<Option<Foo>>) }
-   | ^^^^^^^^                  --- recursive without indirection
+LL | enum Foo { X(UnsafeCell<Option<Foo>>) }
+   | ^^^^^^^^                       --- recursive without indirection
    |
 help: insert some indirection (e.g., a `Box`, `Rc`, or `&`) to break the cycle
    |
-LL | enum Foo { X(Mutex<Option<Box<Foo>>>) }
-   |                           ++++   +
+LL | enum Foo { X(UnsafeCell<Option<Box<Foo>>>) }
+   |                                ++++   +
 
 error[E0391]: cycle detected when computing when `Foo` needs drop
-  --> $DIR/issue-17431-6.rs:5:1
+  --> $DIR/issue-17431-6.rs:3:1
    |
-LL | enum Foo { X(Mutex<Option<Foo>>) }
+LL | enum Foo { X(UnsafeCell<Option<Foo>>) }
    | ^^^^^^^^
    |
    = note: ...which immediately requires computing when `Foo` needs drop again