Stabilize GATs

Author: jackh726

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 {}