Stabilize GATs

compiler/rustc_ast_passes/src/feature_gate.rs

@@ -342,25 +342,6 @@ impl<'a> PostExpansionVisitor<'a> {
         }
     }
 
-    fn check_gat(&self, generics: &ast::Generics, span: Span) {
-        if !generics.params.is_empty() {
-            gate_feature_post!(
-                &self,
-                generic_associated_types,
-                span,
-                "generic associated types are unstable"
-            );
-        }
-        if !generics.where_clause.predicates.is_empty() {
-            gate_feature_post!(
-                &self,
-                generic_associated_types,
-                span,
-                "where clauses on associated types are unstable"
-            );
-        }
-    }
-
     /// Feature gate `impl Trait` inside `type Alias = $type_expr;`.
     fn check_impl_trait(&self, ty: &ast::Ty) {
         struct ImplTraitVisitor<'a> {
@@ -719,7 +700,7 @@ impl<'a> Visitor<'a> for PostExpansionVisitor<'a> {
     fn visit_assoc_item(&mut self, i: &'a ast::AssocItem, ctxt: AssocCtxt) {
         let is_fn = match i.kind {
             ast::AssocItemKind::Fn(_) => true,
-            ast::AssocItemKind::TyAlias(box ast::TyAlias { ref generics, ref ty, .. }) => {
+            ast::AssocItemKind::TyAlias(box ast::TyAlias { ref ty, .. }) => {
                 if let (Some(_), AssocCtxt::Trait) = (ty, ctxt) {
                     gate_feature_post!(
                         &self,
@@ -731,7 +712,6 @@ impl<'a> Visitor<'a> for PostExpansionVisitor<'a> {
                 if let Some(ty) = ty {
                     self.check_impl_trait(ty);
                 }
-                self.check_gat(generics, i.span);
                 false
             }
             _ => false,

compiler/rustc_feature/src/accepted.rs

@@ -161,6 +161,8 @@ declare_features! (
     (accepted, fn_must_use, "1.27.0", Some(43302), None),
     /// Allows capturing variables in scope using format_args!
     (accepted, format_args_capture, "1.58.0", Some(67984), None),
+    /// Allows associated types to be generic, e.g., `type Foo<T>;` (RFC 1598).
+    (accepted, generic_associated_types, "CURRENT_RUSTC_VERSION", Some(44265), None),
     /// Allows attributes on lifetime/type formal parameters in generics (RFC 1327).
     (accepted, generic_param_attrs, "1.27.0", Some(48848), None),
     /// Allows the `#[global_allocator]` attribute.

compiler/rustc_feature/src/active.rs

@@ -398,8 +398,6 @@ declare_features! (
     (active, generators, "1.21.0", Some(43122), None),
     /// Infer generic args for both consts and types.
     (active, generic_arg_infer, "1.55.0", Some(85077), None),
-    /// Allows associated types to be generic, e.g., `type Foo<T>;` (RFC 1598).
-    (active, generic_associated_types, "1.23.0", Some(44265), None),
     /// An extension to the `generic_associated_types` feature, allowing incomplete features.
     (incomplete, generic_associated_types_extended, "1.61.0", Some(95451), None),
     /// Allows non-trivial generic constants which have to have wfness manually propagated to callers

compiler/rustc_lint_defs/src/builtin.rs

@@ -3989,8 +3989,6 @@ declare_lint! {
     /// ### Example
     ///
     /// ```rust
-    /// #![feature(generic_associated_types)]
-    ///
     /// trait Trait {
     ///   type Assoc<'a> where Self: 'a;
     /// }

compiler/rustc_metadata/src/lib.rs

@@ -2,7 +2,7 @@
 #![feature(decl_macro)]
 #![feature(drain_filter)]
 #![feature(generators)]
-#![feature(generic_associated_types)]
+#![cfg_attr(bootstrap, feature(generic_associated_types))]
 #![feature(iter_from_generator)]
 #![feature(let_chains)]
 #![feature(let_else)]

compiler/rustc_middle/src/lib.rs

@@ -31,7 +31,7 @@
 #![feature(discriminant_kind)]
 #![feature(exhaustive_patterns)]
 #![feature(get_mut_unchecked)]
-#![feature(generic_associated_types)]
+#![cfg_attr(bootstrap, feature(generic_associated_types))]
 #![feature(if_let_guard)]
 #![feature(map_first_last)]
 #![feature(negative_impls)]

compiler/rustc_trait_selection/src/traits/project.rs

@@ -2064,8 +2064,6 @@ fn confirm_impl_candidate<'cx, 'tcx>(
 
 // Get obligations corresponding to the predicates from the where-clause of the
 // associated type itself.
-// Note: `feature(generic_associated_types)` is required to write such
-// predicates, even for non-generic associated types.
 fn assoc_ty_own_obligations<'cx, 'tcx>(
     selcx: &mut SelectionContext<'cx, 'tcx>,
     obligation: &ProjectionTyObligation<'tcx>,

src/librustdoc/lib.rs

@@ -16,7 +16,7 @@
 #![feature(type_ascription)]
 #![feature(iter_intersperse)]
 #![feature(type_alias_impl_trait)]
-#![feature(generic_associated_types)]
+#![cfg_attr(bootstrap, feature(generic_associated_types))]
 #![recursion_limit = "256"]
 #![warn(rustc::internal)]
 #![allow(clippy::collapsible_if, clippy::collapsible_else_if)]

src/test/pretty/gat-bounds.rs

@@ -3,8 +3,6 @@
 
 // pretty-compare-only
 
-#![feature(generic_associated_types)]
-
 trait X {
     type Y<T>: Trait where Self: Sized;
 }

src/test/rustdoc-json/generic-associated-types/gats.rs

@@ -1,7 +1,7 @@
 // ignore-tidy-linelength
 
 #![no_core]
-#![feature(generic_associated_types, lang_items, no_core)]
+#![feature(lang_items, no_core)]
 
 #[lang = "sized"]
 pub trait Sized {}

src/test/rustdoc/generic-associated-types/gats.rs

@@ -1,5 +1,4 @@
 #![crate_name = "foo"]
-#![feature(generic_associated_types)]
 
 // @has foo/trait.LendingIterator.html
 pub trait LendingIterator {

src/test/rustdoc/generic-associated-types/issue-94683.rs

@@ -1,5 +1,4 @@
 #![crate_name = "foo"]
-#![feature(generic_associated_types)]
 
 pub trait Trait {
     type Gat<'a>;

src/test/rustdoc/where.rs

@@ -1,4 +1,3 @@
-#![feature(generic_associated_types)]
 #![crate_name = "foo"]
 
 pub trait MyTrait { fn dummy(&self) { } }

src/test/ui/associated-type-bounds/binder-on-bound.rs

@@ -1,5 +1,3 @@
-#![feature(generic_associated_types)]
-
 trait Trait {
     type Bound<'a>;
 }

src/test/ui/associated-type-bounds/binder-on-bound.stderr

@@ -1,5 +1,5 @@
 error: `for<...>` is not allowed on associated type bounds
-  --> $DIR/binder-on-bound.rs:7:22
+  --> $DIR/binder-on-bound.rs:5:22
    |
 LL | fn foo() where Trait<for<'a> Bound<'a> = &'a ()> {
    |                      ^^^^^^^^^^^^^^^^^

src/test/ui/associated-type-bounds/issue-79949.rs

@@ -2,7 +2,6 @@
 
 #![allow(incomplete_features)]
 #![feature(associated_type_bounds)]
-#![feature(generic_associated_types)]
 
 trait MP {
     type T<'a>;

src/test/ui/deriving/issue-89188-gat-hrtb.rs

@@ -1,7 +1,5 @@
 // check-pass
 
-#![feature(generic_associated_types)]
-
 trait CallWithShim: Sized {
     type Shim<'s>
     where

src/test/ui/feature-gates/feature-gate-generic_associated_types_extended.rs

@@ -1,5 +1,3 @@
-#![feature(generic_associated_types)]
-
 // This feature doesn't *currently* fire on any specific code; it's just a
 // behavior change. Future changes might.
 #[rustc_error] //~ the

src/test/ui/feature-gates/feature-gate-generic_associated_types_extended.stderr

@@ -1,5 +1,5 @@
 error[E0658]: the `#[rustc_error]` attribute is just used for rustc unit tests and will never be stable
-  --> $DIR/feature-gate-generic_associated_types_extended.rs:5:1
+  --> $DIR/feature-gate-generic_associated_types_extended.rs:3:1
    |
 LL | #[rustc_error]
    | ^^^^^^^^^^^^^^

src/test/ui/generic-associated-types/anonymize-bound-vars.rs

@@ -1,7 +1,6 @@
 // check-pass
 //
 // regression test for #98702
-#![feature(generic_associated_types)]
 
 trait Foo {
     type Assoc<T>;

src/test/ui/generic-associated-types/auxiliary/foo_defn.rs

@@ -1,5 +1,3 @@
-#![feature(generic_associated_types)]
-
 use std::{future::Future, pin::Pin};
 
 pub trait Foo {

src/test/ui/generic-associated-types/bugs/issue-80626.rs

@@ -3,8 +3,6 @@
 
 // This should pass, but it requires `Sized` to be coinductive.
 
-#![feature(generic_associated_types)]
-
 trait Allocator {
     type Allocated<T>;
 }

src/test/ui/generic-associated-types/bugs/issue-80626.stderr

@@ -1,11 +1,11 @@
 error[E0275]: overflow evaluating the requirement `LinkedList<A>: Sized`
-  --> $DIR/issue-80626.rs:14:10
+  --> $DIR/issue-80626.rs:12:10
    |
 LL |     Next(A::Allocated<Self>)
    |          ^^^^^^^^^^^^^^^^^^
    |
 note: required by a bound in `Allocator::Allocated`
-  --> $DIR/issue-80626.rs:9:20
+  --> $DIR/issue-80626.rs:7:20
    |
 LL |     type Allocated<T>;
    |                    ^ required by this bound in `Allocator::Allocated`

src/test/ui/generic-associated-types/bugs/issue-86218.rs

@@ -3,7 +3,6 @@
 
 // This should pass, but seems to run into a TAIT issue.
 
-#![feature(generic_associated_types)]
 #![feature(type_alias_impl_trait)]
 
 pub trait Stream {

src/test/ui/generic-associated-types/bugs/issue-86218.stderr

@@ -1,17 +1,17 @@
 error[E0477]: the type `<() as Yay<&'a ()>>::InnerStream<'s>` does not fulfill the required lifetime
-  --> $DIR/issue-86218.rs:23:28
+  --> $DIR/issue-86218.rs:22:28
    |
 LL |     type InnerStream<'s> = impl Stream<Item = i32> + 's;
    |                            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
 note: type must outlive the lifetime `'s` as defined here as required by this binding
-  --> $DIR/issue-86218.rs:23:22
+  --> $DIR/issue-86218.rs:22:22
    |
 LL |     type InnerStream<'s> = impl Stream<Item = i32> + 's;
    |                      ^^
 
 error: unconstrained opaque type
-  --> $DIR/issue-86218.rs:23:28
+  --> $DIR/issue-86218.rs:22:28
    |
 LL |     type InnerStream<'s> = impl Stream<Item = i32> + 's;
    |                            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^

src/test/ui/generic-associated-types/bugs/issue-87735.rs

@@ -3,8 +3,6 @@
 
 // This should pass, but we need an extension of implied bounds (probably).
 
-#![feature(generic_associated_types)]
-
 pub trait AsRef2 {
   type Output<'a> where Self: 'a;
 

src/test/ui/generic-associated-types/bugs/issue-87735.stderr

@@ -1,5 +1,5 @@
 error[E0207]: the type parameter `U` is not constrained by the impl trait, self type, or predicates
-  --> $DIR/issue-87735.rs:27:13
+  --> $DIR/issue-87735.rs:25:13
    |
 LL | impl<'b, T, U> AsRef2 for Foo<T>
    |             ^ unconstrained type parameter

src/test/ui/generic-associated-types/bugs/issue-87755.rs

@@ -3,8 +3,6 @@
 
 // This should pass.
 
-#![feature(generic_associated_types)]
-
 use std::fmt::Debug;
 
 trait Foo {

src/test/ui/generic-associated-types/bugs/issue-87755.stderr

@@ -1,5 +1,5 @@
 error[E0275]: overflow evaluating the requirement `<Bar as Foo>::Ass == _`
-  --> $DIR/issue-87755.rs:18:16
+  --> $DIR/issue-87755.rs:16:16
    |
 LL |     type Ass = Bar;
    |                ^^^