Stabilize precise_capturing_in_traits

Author: compiler-errors

compiler/rustc_ast_lowering/messages.ftl

@@ -141,9 +141,6 @@ ast_lowering_never_pattern_with_guard =
 
 ast_lowering_no_precise_captures_on_apit = `use<...>` precise capturing syntax not allowed in argument-position `impl Trait`
 
-ast_lowering_no_precise_captures_on_rpitit = `use<...>` precise capturing syntax is currently not allowed in return-position `impl Trait` in traits
-    .note = currently, return-position `impl Trait` in traits and trait implementations capture all lifetimes in scope
-
 ast_lowering_previously_used_here = previously used here
 
 ast_lowering_register1 = register `{$reg1_name}`

compiler/rustc_ast_lowering/src/errors.rs

@@ -444,14 +444,6 @@ pub(crate) struct NoPreciseCapturesOnApit {
     pub span: Span,
 }
 
-#[derive(Diagnostic)]
-#[diag(ast_lowering_no_precise_captures_on_rpitit)]
-#[note]
-pub(crate) struct NoPreciseCapturesOnRpitit {
-    #[primary_span]
-    pub span: Span,
-}
-
 #[derive(Diagnostic)]
 #[diag(ast_lowering_yield_in_closure)]
 pub(crate) struct YieldInClosure {

compiler/rustc_ast_lowering/src/lib.rs

@@ -1430,28 +1430,6 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         // frequently opened issues show.
         let opaque_ty_span = self.mark_span_with_reason(DesugaringKind::OpaqueTy, span, None);
 
-        // Feature gate for RPITIT + use<..>
-        match origin {
-            rustc_hir::OpaqueTyOrigin::FnReturn { in_trait_or_impl: Some(_), .. } => {
-                if !self.tcx.features().precise_capturing_in_traits()
-                    && let Some(span) = bounds.iter().find_map(|bound| match *bound {
-                        ast::GenericBound::Use(_, span) => Some(span),
-                        _ => None,
-                    })
-                {
-                    let mut diag =
-                        self.tcx.dcx().create_err(errors::NoPreciseCapturesOnRpitit { span });
-                    add_feature_diagnostics(
-                        &mut diag,
-                        self.tcx.sess,
-                        sym::precise_capturing_in_traits,
-                    );
-                    diag.emit();
-                }
-            }
-            _ => {}
-        }
-
         self.lower_opaque_inner(opaque_ty_node_id, origin, opaque_ty_span, |this| {
             this.lower_param_bounds(bounds, itctx)
         })

compiler/rustc_feature/src/accepted.rs

@@ -329,6 +329,8 @@ declare_features! (
     (accepted, pattern_parentheses, "1.31.0", Some(51087)),
     /// Allows `use<'a, 'b, A, B>` in `impl Trait + use<...>` for precise capture of generic args.
     (accepted, precise_capturing, "1.82.0", Some(123432)),
+    /// Allows `use<..>` precise capturign on impl Trait in traits.
+    (accepted, precise_capturing_in_traits, "CURRENT_RUSTC_VERSION", Some(130044)),
     /// Allows procedural macros in `proc-macro` crates.
     (accepted, proc_macro, "1.29.0", Some(38356)),
     /// Allows multi-segment paths in attributes and derives.

compiler/rustc_feature/src/unstable.rs

@@ -597,8 +597,6 @@ declare_features! (
     (incomplete, pin_ergonomics, "1.83.0", Some(130494)),
     /// Allows postfix match `expr.match { ... }`
     (unstable, postfix_match, "1.79.0", Some(121618)),
-    /// Allows `use<..>` precise capturign on impl Trait in traits.
-    (unstable, precise_capturing_in_traits, "1.83.0", Some(130044)),
     /// Allows macro attributes on expressions, statements and non-inline modules.
     (unstable, proc_macro_hygiene, "1.30.0", Some(54727)),
     /// Allows the use of raw-dylibs on ELF platforms

tests/ui/feature-gates/feature-gate-precise_capturing_in_traits.rs

@@ -1,6 +1,6 @@
 //@ compile-flags: -Zverbose-internals
 
-#![feature(precise_capturing_in_traits, rustc_attrs)]
+#![feature(rustc_attrs)]
 #![rustc_hidden_type_of_opaques]
 
 trait Foo {

tests/ui/feature-gates/feature-gate-precise_capturing_in_traits.stderr

@@ -1,5 +1,3 @@
-#![feature(precise_capturing_in_traits)]
-
 trait LifetimeParam<'a> {
     fn test() -> impl Sized;
 }

tests/ui/impl-trait/in-trait/dump.rs

@@ -1,5 +1,5 @@
 warning: impl trait in impl method captures fewer lifetimes than in trait
-  --> $DIR/refine-captures.rs:8:31
+  --> $DIR/refine-captures.rs:6:31
    |
 LL |     fn test() -> impl Sized + use<> {}
    |                               ^^^^^
@@ -13,7 +13,7 @@ LL |     fn test() -> impl Sized + use<'a> {}
    |                                   ++
 
 warning: impl trait in impl method captures fewer lifetimes than in trait
-  --> $DIR/refine-captures.rs:22:31
+  --> $DIR/refine-captures.rs:20:31
    |
 LL |     fn test() -> impl Sized + use<> {}
    |                               ^^^^^
@@ -26,7 +26,7 @@ LL |     fn test() -> impl Sized + use<'a> {}
    |                                   ++
 
 warning: impl trait in impl method captures fewer lifetimes than in trait
-  --> $DIR/refine-captures.rs:27:31
+  --> $DIR/refine-captures.rs:25:31
    |
 LL |     fn test() -> impl Sized + use<'b> {}
    |                               ^^^^^^^
@@ -39,7 +39,7 @@ LL |     fn test() -> impl Sized + use<'a, 'b> {}
    |                                    ++++
 
 error: `impl Trait` must mention all type parameters in scope in `use<...>`
-  --> $DIR/refine-captures.rs:32:18
+  --> $DIR/refine-captures.rs:30:18
    |
 LL | impl<T> TypeParam<T> for u64 {
    |      - type parameter is implicitly captured by this `impl Trait`

tests/ui/impl-trait/in-trait/refine-captures.rs

@@ -1,4 +1,4 @@
-#![feature(rustc_attrs, precise_capturing_in_traits)]
+#![feature(rustc_attrs)]
 #![allow(internal_features)]
 #![rustc_variance_of_opaques]
 

tests/ui/impl-trait/in-trait/refine-captures.stderr

@@ -1,5 +1,3 @@
-#![feature(precise_capturing_in_traits)]
-
 fn type_param<T>() -> impl Sized + use<> {}
 //~^ ERROR `impl Trait` must mention all type parameters in scope
 

tests/ui/impl-trait/in-trait/variance.rs

@@ -1,5 +1,5 @@
 error: `impl Trait` must mention all type parameters in scope in `use<...>`
-  --> $DIR/forgot-to-capture-type.rs:3:23
+  --> $DIR/forgot-to-capture-type.rs:1:23
    |
 LL | fn type_param<T>() -> impl Sized + use<> {}
    |               -       ^^^^^^^^^^^^^^^^^^
@@ -9,7 +9,7 @@ LL | fn type_param<T>() -> impl Sized + use<> {}
    = note: currently, all type parameters are required to be mentioned in the precise captures list
 
 error: `impl Trait` must mention the `Self` type of the trait in `use<...>`
-  --> $DIR/forgot-to-capture-type.rs:7:17
+  --> $DIR/forgot-to-capture-type.rs:5:17
    |
 LL | trait Foo {
    | --------- `Self` type parameter is implicitly captured by this `impl Trait`

tests/ui/impl-trait/precise-capturing/forgot-to-capture-type.rs

@@ -1,6 +1,5 @@
 //@ edition: 2024
 
-#![feature(precise_capturing_in_traits)]
 #![deny(impl_trait_redundant_captures)]
 
 fn hello<'a>() -> impl Sized + use<'a> {}

tests/ui/impl-trait/precise-capturing/forgot-to-capture-type.stderr

@@ -1,35 +1,35 @@
 error: all possible in-scope parameters are already captured, so `use<...>` syntax is redundant
-  --> $DIR/redundant.rs:6:19
+  --> $DIR/redundant.rs:5:19
    |
 LL | fn hello<'a>() -> impl Sized + use<'a> {}
    |                   ^^^^^^^^^^^^^-------
    |                                |
    |                                help: remove the `use<...>` syntax
    |
 note: the lint level is defined here
-  --> $DIR/redundant.rs:4:9
+  --> $DIR/redundant.rs:3:9
    |
 LL | #![deny(impl_trait_redundant_captures)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: all possible in-scope parameters are already captured, so `use<...>` syntax is redundant
-  --> $DIR/redundant.rs:11:27
+  --> $DIR/redundant.rs:10:27
    |
 LL |     fn inherent(&self) -> impl Sized + use<'_> {}
    |                           ^^^^^^^^^^^^^-------
    |                                        |
    |                                        help: remove the `use<...>` syntax
 
 error: all possible in-scope parameters are already captured, so `use<...>` syntax is redundant
-  --> $DIR/redundant.rs:16:22
+  --> $DIR/redundant.rs:15:22
    |
 LL |     fn in_trait() -> impl Sized + use<'a, Self>;
    |                      ^^^^^^^^^^^^^-------------
    |                                   |
    |                                   help: remove the `use<...>` syntax
 
 error: all possible in-scope parameters are already captured, so `use<...>` syntax is redundant
-  --> $DIR/redundant.rs:20:22
+  --> $DIR/redundant.rs:19:22
    |
 LL |     fn in_trait() -> impl Sized + use<'a> {}
    |                      ^^^^^^^^^^^^^-------

tests/ui/impl-trait/precise-capturing/redundant.rs

@@ -2,8 +2,6 @@
 // trait definition, which is not allowed. Due to the default lifetime capture
 // rules of RPITITs, this is only doable if we use precise capturing.
 
-#![feature(precise_capturing_in_traits)]
-
 pub trait Foo {
     fn bar<'tr: 'tr>(&'tr mut self) -> impl Sized + use<Self>;
 }

tests/ui/impl-trait/precise-capturing/redundant.stderr

@@ -1,13 +1,13 @@
 error: return type captures more lifetimes than trait definition
-  --> $DIR/rpitit-captures-more-method-lifetimes.rs:12:40
+  --> $DIR/rpitit-captures-more-method-lifetimes.rs:10:40
    |
 LL |     fn bar<'im: 'im>(&'im mut self) -> impl Sized + use<'im> {}
    |            ---                         ^^^^^^^^^^^^^^^^^^^^^
    |            |
    |            this lifetime was captured
    |
 note: hidden type must only reference lifetimes captured by this impl trait
-  --> $DIR/rpitit-captures-more-method-lifetimes.rs:8:40
+  --> $DIR/rpitit-captures-more-method-lifetimes.rs:6:40
    |
 LL |     fn bar<'tr: 'tr>(&'tr mut self) -> impl Sized + use<Self>;
    |                                        ^^^^^^^^^^^^^^^^^^^^^^

tests/ui/impl-trait/precise-capturing/rpitit-captures-more-method-lifetimes.rs

@@ -1,5 +1,3 @@
-#![feature(precise_capturing_in_traits)]
-
 struct Invariant<'a>(&'a mut &'a mut ());
 
 trait Trait {

tests/ui/impl-trait/precise-capturing/rpitit-captures-more-method-lifetimes.stderr

@@ -1,5 +1,5 @@
 error: return type captures more lifetimes than trait definition
-  --> $DIR/rpitit-impl-captures-too-much.rs:10:39
+  --> $DIR/rpitit-impl-captures-too-much.rs:8:39
    |
 LL |     fn hello(self_: Invariant<'_>) -> impl Sized + use<Self>;
    |                               -- this lifetime was captured
@@ -8,7 +8,7 @@ LL |     fn hello(self_: Invariant<'_>) -> impl Sized + use<'_> {}
    |                                       ^^^^^^^^^^^^^^^^^^^^
    |
 note: hidden type must only reference lifetimes captured by this impl trait
-  --> $DIR/rpitit-impl-captures-too-much.rs:6:39
+  --> $DIR/rpitit-impl-captures-too-much.rs:4:39
    |
 LL |     fn hello(self_: Invariant<'_>) -> impl Sized + use<Self>;
    |                                       ^^^^^^^^^^^^^^^^^^^^^^

tests/ui/impl-trait/precise-capturing/rpitit-impl-captures-too-much.rs

@@ -2,8 +2,6 @@
 
 // Ensure that we skip uncaptured args from RPITITs when comptuing outlives.
 
-#![feature(precise_capturing_in_traits)]
-
 struct Invariant<T>(*mut T);
 
 trait Foo {

tests/ui/impl-trait/precise-capturing/rpitit-impl-captures-too-much.stderr

@@ -3,8 +3,6 @@
 // Ensure that we skip uncaptured args from RPITITs when collecting the regions
 // to enforce member constraints in opaque type inference.
 
-#![feature(precise_capturing_in_traits)]
-
 struct Invariant<T>(*mut T);
 
 trait Foo {

tests/ui/impl-trait/precise-capturing/rpitit-outlives-2.rs

@@ -3,8 +3,6 @@
 // To fix this soundly, we need to make sure that all the trait header args
 // remain captured, since they affect trait selection.
 
-#![feature(precise_capturing_in_traits)]
-
 fn eq_types<T>(_: T, _: T) {}
 
 trait TraitLt<'a: 'a> {

tests/ui/impl-trait/precise-capturing/rpitit-outlives.rs

@@ -1,13 +1,13 @@
 error: `impl Trait` captures lifetime parameter, but it is not mentioned in `use<...>` precise captures list
-  --> $DIR/rpitit.rs:11:19
+  --> $DIR/rpitit.rs:9:19
    |
 LL | trait TraitLt<'a: 'a> {
    |               -- all lifetime parameters originating from a trait are captured implicitly
 LL |     fn hello() -> impl Sized + use<Self>;
    |                   ^^^^^^^^^^^^^^^^^^^^^^
 
 error: lifetime may not live long enough
-  --> $DIR/rpitit.rs:15:5
+  --> $DIR/rpitit.rs:13:5
    |
 LL |   fn trait_lt<'a, 'b, T: for<'r> TraitLt<'r>> () {
    |               --  -- lifetime `'b` defined here
@@ -24,7 +24,7 @@ LL | |     );
    = help: consider adding the following bound: `'a: 'b`
 
 error: lifetime may not live long enough
-  --> $DIR/rpitit.rs:15:5
+  --> $DIR/rpitit.rs:13:5
    |
 LL |   fn trait_lt<'a, 'b, T: for<'r> TraitLt<'r>> () {
    |               --  -- lifetime `'b` defined here

tests/ui/impl-trait/precise-capturing/rpitit.rs

@@ -1,7 +1,5 @@
 //@ check-pass
 
-#![feature(precise_capturing_in_traits)]
-
 trait Foo {
     fn bar<'a>() -> impl Sized + use<Self>;
 }