Stabilize associated type bounds

compiler/rustc_ast/src/lib.rs

@@ -11,7 +11,7 @@
 #![doc(rust_logo)]
 #![allow(internal_features)]
 #![feature(rustdoc_internals)]
-#![feature(associated_type_bounds)]
+#![cfg_attr(bootstrap, feature(associated_type_bounds))]
 #![feature(associated_type_defaults)]
 #![feature(box_patterns)]
 #![feature(if_let_guard)]

compiler/rustc_ast_passes/src/feature_gate.rs

@@ -457,13 +457,6 @@ impl<'a> Visitor<'a> for PostExpansionVisitor<'a> {
                     constraint.span,
                     "return type notation is experimental"
                 );
-            } else {
-                gate!(
-                    &self,
-                    associated_type_bounds,
-                    constraint.span,
-                    "associated type bounds are unstable"
-                );
             }
         }
         visit::walk_assoc_constraint(self, constraint)
@@ -608,7 +601,6 @@ pub fn check_crate(krate: &ast::Crate, sess: &Session, features: &Features) {
     }
 
     gate_all_legacy_dont_use!(trait_alias, "trait aliases are experimental");
-    gate_all_legacy_dont_use!(associated_type_bounds, "associated type bounds are unstable");
     // Despite being a new feature, `where T: Trait<Assoc(): Sized>`, which is RTN syntax now,
     // used to be gated under associated_type_bounds, which are right above, so RTN needs to
     // be too.

compiler/rustc_borrowck/src/lib.rs

@@ -4,7 +4,7 @@
 #![feature(rustdoc_internals)]
 #![doc(rust_logo)]
 #![feature(assert_matches)]
-#![feature(associated_type_bounds)]
+#![cfg_attr(bootstrap, feature(associated_type_bounds))]
 #![feature(box_patterns)]
 #![feature(let_chains)]
 #![feature(min_specialization)]

compiler/rustc_codegen_gcc/src/lib.rs

@@ -18,11 +18,11 @@
 #![feature(
     rustc_private,
     decl_macro,
-    associated_type_bounds,
     never_type,
     trusted_len,
     hash_raw_entry
 )]
+#![cfg_attr(bootstrap, feature(associated_type_bounds))]
 #![allow(broken_intra_doc_links)]
 #![recursion_limit="256"]
 #![warn(rust_2018_idioms)]

compiler/rustc_codegen_ssa/src/lib.rs

@@ -4,7 +4,7 @@
 #![allow(internal_features)]
 #![allow(rustc::diagnostic_outside_of_impl)]
 #![allow(rustc::untranslatable_diagnostic)]
-#![feature(associated_type_bounds)]
+#![cfg_attr(bootstrap, feature(associated_type_bounds))]
 #![feature(box_patterns)]
 #![feature(if_let_guard)]
 #![feature(let_chains)]

compiler/rustc_error_codes/src/error_codes/E0719.md

@@ -3,8 +3,6 @@ An associated type value was specified more than once.
 Erroneous code example:
 
 ```compile_fail,E0719
-#![feature(associated_type_bounds)]
-
 trait FooTrait {}
 trait BarTrait {}
 
@@ -19,8 +17,6 @@ specify the associated type with the new trait.
 Corrected example:
 
 ```
-#![feature(associated_type_bounds)]
-
 trait FooTrait {}
 trait BarTrait {}
 trait FooBarTrait: FooTrait + BarTrait {}

compiler/rustc_expand/src/lib.rs

@@ -1,7 +1,7 @@
 #![doc(rust_logo)]
 #![feature(rustdoc_internals)]
 #![feature(array_windows)]
-#![feature(associated_type_bounds)]
+#![cfg_attr(bootstrap, feature(associated_type_bounds))]
 #![feature(associated_type_defaults)]
 #![feature(if_let_guard)]
 #![feature(let_chains)]

compiler/rustc_feature/src/accepted.rs

@@ -59,6 +59,8 @@ declare_features! (
     (accepted, asm_sym, "1.66.0", Some(93333)),
     /// Allows the definition of associated constants in `trait` or `impl` blocks.
     (accepted, associated_consts, "1.20.0", Some(29646)),
+    /// Allows the user of associated type bounds.
+    (accepted, associated_type_bounds, "CURRENT_RUSTC_VERSION", Some(52662)),
     /// Allows using associated `type`s in `trait`s.
     (accepted, associated_types, "1.0.0", None),
     /// Allows free and inherent `async fn`s, `async` blocks, and `<expr>.await` expressions.

compiler/rustc_feature/src/unstable.rs

@@ -349,8 +349,6 @@ declare_features! (
     (unstable, asm_unwind, "1.58.0", Some(93334)),
     /// Allows users to enforce equality of associated constants `TraitImpl<AssocConst=3>`.
     (unstable, associated_const_equality, "1.58.0", Some(92827)),
-    /// Allows the user of associated type bounds.
-    (unstable, associated_type_bounds, "1.34.0", Some(52662)),
     /// Allows associated type defaults.
     (unstable, associated_type_defaults, "1.2.0", Some(29661)),
     /// Allows `async || body` closures.

compiler/rustc_infer/src/lib.rs

@@ -18,7 +18,7 @@
 #![allow(internal_features)]
 #![allow(rustc::diagnostic_outside_of_impl)]
 #![allow(rustc::untranslatable_diagnostic)]
-#![feature(associated_type_bounds)]
+#![cfg_attr(bootstrap, feature(associated_type_bounds))]
 #![feature(box_patterns)]
 #![feature(extend_one)]
 #![feature(let_chains)]

compiler/rustc_middle/src/lib.rs

@@ -48,7 +48,7 @@
 #![feature(trusted_len)]
 #![feature(type_alias_impl_trait)]
 #![feature(strict_provenance)]
-#![feature(associated_type_bounds)]
+#![cfg_attr(bootstrap, feature(associated_type_bounds))]
 #![feature(rustc_attrs)]
 #![feature(control_flow_enum)]
 #![feature(trait_upcasting)]

compiler/rustc_mir_build/src/lib.rs

@@ -5,7 +5,7 @@
 #![allow(rustc::diagnostic_outside_of_impl)]
 #![allow(rustc::untranslatable_diagnostic)]
 #![feature(assert_matches)]
-#![feature(associated_type_bounds)]
+#![cfg_attr(bootstrap, feature(associated_type_bounds))]
 #![feature(box_patterns)]
 #![feature(if_let_guard)]
 #![feature(let_chains)]

compiler/rustc_parse/src/parser/path.rs

@@ -639,8 +639,6 @@ impl<'a> Parser<'a> {
                             && matches!(args.output, ast::FnRetTy::Default(..))
                         {
                             self.sess.gated_spans.gate(sym::return_type_notation, span);
-                        } else {
-                            self.sess.gated_spans.gate(sym::associated_type_bounds, span);
                         }
                     }
                     let constraint =

compiler/rustc_serialize/src/lib.rs

@@ -8,7 +8,7 @@
 #![doc(rust_logo)]
 #![allow(internal_features)]
 #![feature(rustdoc_internals)]
-#![feature(associated_type_bounds)]
+#![cfg_attr(bootstrap, feature(associated_type_bounds))]
 #![feature(const_option)]
 #![feature(core_intrinsics)]
 #![feature(generic_nonzero)]

compiler/rustc_trait_selection/src/lib.rs

@@ -17,7 +17,7 @@
 #![allow(rustc::diagnostic_outside_of_impl)]
 #![allow(rustc::untranslatable_diagnostic)]
 #![feature(assert_matches)]
-#![feature(associated_type_bounds)]
+#![cfg_attr(bootstrap, feature(associated_type_bounds))]
 #![feature(box_patterns)]
 #![feature(control_flow_enum)]
 #![feature(extract_if)]

compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs

@@ -194,8 +194,7 @@ pub fn suggest_restriction<'tcx, G: EmissionGuarantee>(
         sugg.extend(ty_spans.into_iter().map(|s| (s, type_param_name.to_string())));
 
         // Suggest `fn foo<T: Trait>(t: T) where <T as Trait>::A: Bound`.
-        // FIXME: once `#![feature(associated_type_bounds)]` is stabilized, we should suggest
-        // `fn foo(t: impl Trait<A: Bound>)` instead.
+        // FIXME: we should suggest `fn foo(t: impl Trait<A: Bound>)` instead.
         err.multipart_suggestion(
             "introduce a type parameter with a trait bound instead of using `impl Trait`",
             sugg,

library/alloc/src/lib.rs

@@ -172,12 +172,12 @@
 //
 // Language features:
 // tidy-alphabetical-start
+#![cfg_attr(bootstrap, feature(associated_type_bounds))]
 #![cfg_attr(not(test), feature(coroutine_trait))]
 #![cfg_attr(test, feature(panic_update_hook))]
 #![cfg_attr(test, feature(test))]
 #![feature(allocator_internals)]
 #![feature(allow_internal_unstable)]
-#![feature(associated_type_bounds)]
 #![feature(c_unwind)]
 #![feature(cfg_sanitize)]
 #![feature(const_mut_refs)]

library/core/src/lib.rs

@@ -202,13 +202,13 @@
 //
 // Language features:
 // tidy-alphabetical-start
+#![cfg_attr(bootstrap, feature(associated_type_bounds))]
 #![cfg_attr(bootstrap, feature(platform_intrinsics))]
 #![feature(abi_unadjusted)]
 #![feature(adt_const_params)]
 #![feature(allow_internal_unsafe)]
 #![feature(allow_internal_unstable)]
 #![feature(asm_const)]
-#![feature(associated_type_bounds)]
 #![feature(auto_traits)]
 #![feature(c_unwind)]
 #![feature(cfg_sanitize)]

tests/ui/associated-consts/issue-93835.rs

@@ -6,7 +6,6 @@ fn e() {
     //~| ERROR cannot find value
     //~| ERROR associated const equality
     //~| ERROR cannot find trait `p` in this scope
-    //~| ERROR associated type bounds
 }
 
 fn main() {}

tests/ui/associated-consts/issue-93835.stderr

@@ -26,17 +26,7 @@ LL |     type_ascribe!(p, a<p:p<e=6>>);
    = help: add `#![feature(associated_const_equality)]` 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]: associated type bounds are unstable
-  --> $DIR/issue-93835.rs:4:24
-   |
-LL |     type_ascribe!(p, a<p:p<e=6>>);
-   |                        ^^^^^^^^
-   |
-   = note: see issue #52662 <https://github.com/rust-lang/rust/issues/52662> for more information
-   = help: add `#![feature(associated_type_bounds)]` 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 5 previous errors
+error: aborting due to 4 previous errors
 
 Some errors have detailed explanations: E0405, E0412, E0425, E0658.
 For more information about an error, try `rustc --explain E0405`.

tests/ui/associated-type-bounds/ambiguous-associated-type.rs

@@ -1,7 +1,5 @@
 //@ check-pass
 
-#![feature(associated_type_bounds)]
-
 pub struct Flatten<I>
 where
     I: Iterator<Item: IntoIterator>,

tests/ui/associated-type-bounds/assoc-type-eq-with-dyn-atb-fail.rs

@@ -8,8 +8,6 @@
 // Additionally, as reported in https://github.com/rust-lang/rust/issues/63594,
 // we check that the spans for the error message are sane here.
 
-#![feature(associated_type_bounds)]
-
 fn main() {}
 
 trait Bar {

tests/ui/associated-type-bounds/assoc-type-eq-with-dyn-atb-fail.stderr

@@ -1,5 +1,5 @@
 error: associated type bounds are not allowed in `dyn` types
-  --> $DIR/assoc-type-eq-with-dyn-atb-fail.rs:30:28
+  --> $DIR/assoc-type-eq-with-dyn-atb-fail.rs:28:28
    |
 LL |     type Out = Box<dyn Bar<Assoc: Copy>>;
    |                            ^^^^^^^^^^^

tests/ui/associated-type-bounds/bad-bounds-on-assoc-in-trait.rs

@@ -1,7 +1,5 @@
 //@ check-pass
 
-#![feature(associated_type_bounds)]
-
 use std::fmt::Debug;
 use std::iter::Once;
 

tests/ui/associated-type-bounds/bad-universal-in-dyn-in-where-clause.rs

@@ -1,5 +1,3 @@
-#![feature(associated_type_bounds)]
-
 trait B {
     type AssocType;
 }

tests/ui/associated-type-bounds/bad-universal-in-dyn-in-where-clause.stderr

@@ -1,5 +1,5 @@
 error: associated type bounds are not allowed in `dyn` types
-  --> $DIR/bad-universal-in-dyn-in-where-clause.rs:9:19
+  --> $DIR/bad-universal-in-dyn-in-where-clause.rs:7:19
    |
 LL |     dyn for<'j> B<AssocType: 'j>:,
    |                   ^^^^^^^^^^^^^

tests/ui/associated-type-bounds/bad-universal-in-impl-sig.rs

@@ -1,5 +1,3 @@
-#![feature(associated_type_bounds)]
-
 trait Trait {
     type Item;
 }

tests/ui/associated-type-bounds/bad-universal-in-impl-sig.stderr

@@ -1,5 +1,5 @@
 error: associated type bounds are not allowed in `dyn` types
-  --> $DIR/bad-universal-in-impl-sig.rs:10:16
+  --> $DIR/bad-universal-in-impl-sig.rs:8:16
    |
 LL | impl dyn Trait<Item: Trait2> {}
    |                ^^^^^^^^^^^^

tests/ui/associated-type-bounds/bounds-on-assoc-in-trait.rs

@@ -1,7 +1,5 @@
 //@ check-pass
 
-#![feature(associated_type_bounds)]
-
 use std::fmt::Debug;
 use std::iter::Empty;
 use std::ops::Range;

tests/ui/associated-type-bounds/consts.rs

@@ -1,5 +1,3 @@
-#![feature(associated_type_bounds)]
-
 pub fn accept(_: impl Trait<K: Copy>) {}
 //~^ ERROR expected type, found constant
 

tests/ui/associated-type-bounds/consts.stderr

@@ -1,13 +1,13 @@
 error: expected type, found constant
-  --> $DIR/consts.rs:3:29
+  --> $DIR/consts.rs:1:29
    |
 LL | pub fn accept(_: impl Trait<K: Copy>) {}
    |                             ^------ bounds are not allowed on associated constants
    |                             |
    |                             unexpected constant
    |
 note: the associated constant is defined here
-  --> $DIR/consts.rs:7:5
+  --> $DIR/consts.rs:5:5
    |
 LL |     const K: i32;
    |     ^^^^^^^^^^^^

tests/ui/associated-type-bounds/duplicate.rs

@@ -1,4 +1,3 @@
-#![feature(associated_type_bounds)]
 #![feature(type_alias_impl_trait)]
 
 use std::iter;