Merge associated_const_equality feature gate into MGCA

compiler/rustc_ast_passes/src/feature_gate.rs

@@ -505,7 +505,6 @@ pub fn check_crate(krate: &ast::Crate, sess: &Session, features: &Features) {
         half_open_range_patterns_in_slices,
         "half-open range patterns in slices are unstable"
     );
-    gate_all!(associated_const_equality, "associated const equality is incomplete");
     gate_all!(yeet_expr, "`do yeet` expression is experimental");
     gate_all!(const_closures, "const closures are experimental");
     gate_all!(builtin_syntax, "`builtin #` syntax is unstable");
@@ -518,6 +517,23 @@ pub fn check_crate(krate: &ast::Crate, sess: &Session, features: &Features) {
     gate_all!(postfix_match, "postfix match is experimental");
     gate_all!(mut_ref, "mutable by-reference bindings are experimental");
     gate_all!(min_generic_const_args, "unbraced const blocks as const args are experimental");
+    // associated_const_equality is stabilized as part of min_generic_const_args
+    if let Some(spans) = spans.get(&sym::associated_const_equality) {
+        for span in spans {
+            if !visitor.features.min_generic_const_args()
+                && !span.allows_unstable(sym::min_generic_const_args)
+            {
+                #[allow(rustc::untranslatable_diagnostic)]
+                feature_err(
+                    &visitor.sess,
+                    sym::min_generic_const_args,
+                    *span,
+                    "associated const equality is incomplete",
+                )
+                .emit();
+            }
+        }
+    }
     gate_all!(global_registration, "global registration is experimental");
     gate_all!(return_type_notation, "return type notation is experimental");
     gate_all!(pin_ergonomics, "pinned reference syntax is experimental");

compiler/rustc_codegen_ssa/src/debuginfo/type_names.rs

@@ -260,7 +260,7 @@ fn push_debuginfo_type_name<'tcx>(
                     .map(|bound| {
                         let ExistentialProjection { def_id: item_def_id, term, .. } =
                             tcx.instantiate_bound_regions_with_erased(bound);
-                        // FIXME(associated_const_equality): allow for consts here
+                        // FIXME(mgca): allow for consts here
                         (item_def_id, term.expect_type())
                     })
                     .collect();

compiler/rustc_feature/src/removed.rs

@@ -60,6 +60,9 @@ declare_features! (
     (removed, allocator, "1.0.0", None, None),
     /// Allows a test to fail without failing the whole suite.
     (removed, allow_fail, "1.60.0", Some(46488), Some("removed due to no clear use cases"), 93416),
+    /// Allows users to enforce equality of associated constants `TraitImpl<AssocConst=3>`.
+    (removed, associated_const_equality, "CURRENT_RUSTC_VERSION", Some(92827),
+     Some("merged into `min_generic_const_args`")),
     (removed, await_macro, "1.38.0", Some(50547),
      Some("subsumed by `.await` syntax"), 62293),
     /// Allows using the `box $expr` syntax.

compiler/rustc_feature/src/unstable.rs

@@ -363,8 +363,6 @@ declare_features! (
     (unstable, asm_goto_with_outputs, "1.85.0", Some(119364)),
     /// Allows the `may_unwind` option in inline assembly.
     (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 associated type defaults.
     (unstable, associated_type_defaults, "1.2.0", Some(29661)),
     /// Allows implementing `AsyncDrop`.

compiler/rustc_hir_analysis/src/hir_ty_lowering/bounds.rs

@@ -610,9 +610,7 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
                                 AttributeKind::TypeConst(_)
                             )
                         {
-                            if tcx.features().min_generic_const_args()
-                                || tcx.features().associated_const_equality()
-                            {
+                            if tcx.features().min_generic_const_args() {
                                 let mut err = self.dcx().struct_span_err(
                                     constraint.span,
                                     "use of trait associated const without `#[type_const]`",

compiler/rustc_hir_analysis/src/hir_ty_lowering/dyn_trait.rs

@@ -239,7 +239,7 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
                         // `trait_object_dummy_self`, so check for that.
                         let references_self = match pred.skip_binder().term.kind() {
                             ty::TermKind::Ty(ty) => ty.walk().any(|arg| arg == dummy_self.into()),
-                            // FIXME(associated_const_equality): We should walk the const instead of not doing anything
+                            // FIXME(mgca): We should walk the const instead of not doing anything
                             ty::TermKind::Const(_) => false,
                         };
 

compiler/rustc_hir_analysis/src/hir_ty_lowering/errors.rs

@@ -359,12 +359,12 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
             None
         };
 
-        // FIXME(associated_const_equality): This has quite a few false positives and negatives.
+        // FIXME(mgca): This has quite a few false positives and negatives.
         let wrap_in_braces_sugg = if let Some(constraint) = constraint
             && let Some(hir_ty) = constraint.ty()
             && let ty = self.lower_ty(hir_ty)
             && (ty.is_enum() || ty.references_error())
-            && tcx.features().associated_const_equality()
+            && tcx.features().min_generic_const_args()
         {
             Some(errors::AssocKindMismatchWrapInBracesSugg {
                 lo: hir_ty.span.shrink_to_lo(),

compiler/rustc_middle/src/ty/context.rs

@@ -907,10 +907,6 @@ impl<'tcx> rustc_type_ir::inherent::Features<TyCtxt<'tcx>> for &'tcx rustc_featu
         self.coroutine_clone()
     }
 
-    fn associated_const_equality(self) -> bool {
-        self.associated_const_equality()
-    }
-
     fn feature_bound_holds_in_crate(self, symbol: Symbol) -> bool {
         // We don't consider feature bounds to hold in the crate when `staged_api` feature is
         // enabled, even if it is enabled through `#[feature]`.

compiler/rustc_next_trait_solver/src/solve/assembly/structural_traits.rs

@@ -868,7 +868,7 @@ where
             .map(|(pred, _)| pred),
     ));
 
-    // FIXME(associated_const_equality): Also add associated consts to
+    // FIXME(mgca): Also add associated consts to
     // the requirements here.
     for associated_type_def_id in cx.associated_type_def_ids(trait_ref.def_id) {
         // associated types that require `Self: Sized` do not show up in the built-in

compiler/rustc_type_ir/src/inherent.rs

@@ -646,8 +646,6 @@ pub trait Features<I: Interner>: Copy {
 
     fn coroutine_clone(self) -> bool;
 
-    fn associated_const_equality(self) -> bool;
-
     fn feature_bound_holds_in_crate(self, symbol: I::Symbol) -> bool;
 }
 

src/tools/clippy/tests/ui/trait_duplication_in_bounds_assoc_const_eq.fixed

@@ -1,6 +1,6 @@
 #![deny(clippy::trait_duplication_in_bounds)]
 #![expect(incomplete_features)]
-#![feature(associated_const_equality, min_generic_const_args)]
+#![feature(min_generic_const_args)]
 
 trait AssocConstTrait {
     #[type_const]

src/tools/clippy/tests/ui/trait_duplication_in_bounds_assoc_const_eq.rs

@@ -1,6 +1,6 @@
 #![deny(clippy::trait_duplication_in_bounds)]
 #![expect(incomplete_features)]
-#![feature(associated_const_equality, min_generic_const_args)]
+#![feature(min_generic_const_args)]
 
 trait AssocConstTrait {
     #[type_const]

src/tools/rust-analyzer/crates/hir-ty/src/lower.rs

@@ -862,7 +862,7 @@ impl<'db, 'a> TyLoweringContext<'db, 'a> {
                                 TermKind::Ty(ty) => {
                                     ty.walk().any(|arg| arg == dummy_self_ty.into())
                                 }
-                                // FIXME(associated_const_equality): We should walk the const instead of not doing anything
+                                // FIXME(mgca): We should walk the const instead of not doing anything
                                 TermKind::Const(_) => false,
                             };
 

tests/crashes/mgca/ace-with-const-ctor.rs

@@ -3,7 +3,7 @@
 // readded once fixed.
 // Previous issue (before mgca): https://github.com/rust-lang/rust/issues/105952
 #![crate_name = "foo"]
-#![feature(associated_const_equality, min_generic_const_args)]
+#![feature(min_generic_const_args)]
 pub enum ParseMode {
     Raw,
 }

tests/rustdoc-ui/associated-constant-not-allowed-102467.rs

@@ -2,7 +2,7 @@
 // It ensures that the expected error is displayed.
 
 #![expect(incomplete_features)]
-#![feature(associated_const_equality, min_generic_const_args)]
+#![feature(min_generic_const_args)]
 
 trait T {
     type A: S<C<X = 0i32> = 34>;

tests/rustdoc/inline_cross/auxiliary/assoc-const-equality.rs

@@ -1,5 +1,5 @@
 #![expect(incomplete_features)]
-#![feature(associated_const_equality, min_generic_const_args)]
+#![feature(min_generic_const_args)]
 
 pub fn accept(_: impl Trait<K = 0>) {}
 

tests/ui/associated-consts/assoc-const-eq-ambiguity.rs

@@ -1,7 +1,7 @@
 // We used to say "ambiguous associated type" on ambiguous associated consts.
 // Ensure that we now use the correct label.
 
-#![feature(associated_const_equality, min_generic_const_args, unsized_const_params)]
+#![feature(min_generic_const_args, unsized_const_params)]
 #![allow(incomplete_features)]
 
 trait Trait0: Parent0<i32> + Parent0<u32> {}

tests/ui/associated-consts/assoc-const-eq-bound-var-in-ty-not-wf.rs

@@ -1,7 +1,6 @@
 // Check that we eventually catch types of assoc const bounds
 // (containing late-bound vars) that are ill-formed.
 #![feature(
-    associated_const_equality,
     min_generic_const_args,
     adt_const_params,
     unsized_const_params,

tests/ui/associated-consts/assoc-const-eq-bound-var-in-ty-not-wf.stderr

@@ -1,11 +1,11 @@
 error: higher-ranked subtype error
-  --> $DIR/assoc-const-eq-bound-var-in-ty-not-wf.rs:22:13
+  --> $DIR/assoc-const-eq-bound-var-in-ty-not-wf.rs:21:13
    |
 LL |         K = const { () }
    |             ^^^^^^^^^^^^
 
 error: higher-ranked subtype error
-  --> $DIR/assoc-const-eq-bound-var-in-ty-not-wf.rs:22:13
+  --> $DIR/assoc-const-eq-bound-var-in-ty-not-wf.rs:21:13
    |
 LL |         K = const { () }
    |             ^^^^^^^^^^^^

tests/ui/associated-consts/assoc-const-eq-bound-var-in-ty.rs

@@ -4,7 +4,6 @@
 //@ check-pass
 
 #![feature(
-    associated_const_equality,
     min_generic_const_args,
     adt_const_params,
     unsized_const_params,

tests/ui/associated-consts/assoc-const-eq-const_evaluatable_unchecked.rs

@@ -4,7 +4,7 @@
 //
 // issue: <https://github.com/rust-lang/rust/issues/108220>
 //@ check-pass
-#![feature(associated_const_equality, min_generic_const_args)]
+#![feature(min_generic_const_args)]
 #![allow(incomplete_features)]
 
 pub trait TraitA<T> {

tests/ui/associated-consts/assoc-const-eq-esc-bound-var-in-ty.rs

@@ -1,7 +1,6 @@
 // Detect and reject escaping late-bound generic params in
 // the type of assoc consts used in an equality bound.
 #![feature(
-    associated_const_equality,
     min_generic_const_args,
     unsized_const_params,
     generic_const_parameter_types,

tests/ui/associated-consts/assoc-const-eq-esc-bound-var-in-ty.stderr

@@ -1,5 +1,5 @@
 error: the type of the associated constant `K` cannot capture late-bound generic parameters
-  --> $DIR/assoc-const-eq-esc-bound-var-in-ty.rs:16:35
+  --> $DIR/assoc-const-eq-esc-bound-var-in-ty.rs:15:35
    |
 LL | fn take(_: impl for<'r> Trait<'r, K = const { &() }>) {}
    |                     --            ^ its type cannot capture the late-bound lifetime parameter `'r`

tests/ui/associated-consts/assoc-const-eq-missing.rs

@@ -1,5 +1,5 @@
-#![feature(associated_const_equality)]
-#![allow(unused)]
+#![feature(min_generic_const_args)]
+#![allow(incomplete_features, unused)]
 
 pub trait Foo {
   const N: usize;

tests/ui/associated-consts/assoc-const-eq-param-in-ty.rs

@@ -1,7 +1,6 @@
 // Regression test for issue #108271.
 // Detect and reject generic params in the type of assoc consts used in an equality bound.
 #![feature(
-    associated_const_equality,
     min_generic_const_args,
     adt_const_params,
     unsized_const_params,

tests/ui/associated-consts/assoc-const-eq-param-in-ty.stderr

@@ -1,5 +1,5 @@
 error: the type of the associated constant `K` must not depend on generic parameters
-  --> $DIR/assoc-const-eq-param-in-ty.rs:23:29
+  --> $DIR/assoc-const-eq-param-in-ty.rs:22:29
    |
 LL | fn take0<'r, A: 'r + ConstParamTy_, const Q: usize>(
    |          -- the lifetime parameter `'r` is defined here
@@ -10,7 +10,7 @@ LL |     _: impl Trait<'r, A, Q, K = const { loop {} }>
    = note: `K` has type `&'r [A; Q]`
 
 error: the type of the associated constant `K` must not depend on generic parameters
-  --> $DIR/assoc-const-eq-param-in-ty.rs:23:29
+  --> $DIR/assoc-const-eq-param-in-ty.rs:22:29
    |
 LL | fn take0<'r, A: 'r + ConstParamTy_, const Q: usize>(
    |              - the type parameter `A` is defined here
@@ -21,7 +21,7 @@ LL |     _: impl Trait<'r, A, Q, K = const { loop {} }>
    = note: `K` has type `&'r [A; Q]`
 
 error: the type of the associated constant `K` must not depend on generic parameters
-  --> $DIR/assoc-const-eq-param-in-ty.rs:23:29
+  --> $DIR/assoc-const-eq-param-in-ty.rs:22:29
    |
 LL | fn take0<'r, A: 'r + ConstParamTy_, const Q: usize>(
    |                                           - the const parameter `Q` is defined here
@@ -32,7 +32,7 @@ LL |     _: impl Trait<'r, A, Q, K = const { loop {} }>
    = note: `K` has type `&'r [A; Q]`
 
 error: the type of the associated constant `SELF` must not depend on `impl Trait`
-  --> $DIR/assoc-const-eq-param-in-ty.rs:40:26
+  --> $DIR/assoc-const-eq-param-in-ty.rs:39:26
    |
 LL | fn take1(_: impl Project<SELF = const {}>) {}
    |             -------------^^^^------------
@@ -41,7 +41,7 @@ LL | fn take1(_: impl Project<SELF = const {}>) {}
    |             the `impl Trait` is specified here
 
 error: the type of the associated constant `SELF` must not depend on generic parameters
-  --> $DIR/assoc-const-eq-param-in-ty.rs:45:21
+  --> $DIR/assoc-const-eq-param-in-ty.rs:44:21
    |
 LL | fn take2<P: Project<SELF = const {}>>(_: P) {}
    |          -          ^^^^ its type must not depend on the type parameter `P`
@@ -51,7 +51,7 @@ LL | fn take2<P: Project<SELF = const {}>>(_: P) {}
    = note: `SELF` has type `P`
 
 error: the type of the associated constant `K` must not depend on generic parameters
-  --> $DIR/assoc-const-eq-param-in-ty.rs:54:52
+  --> $DIR/assoc-const-eq-param-in-ty.rs:53:52
    |
 LL | trait Iface<'r>: ConstParamTy_ {
    |             -- the lifetime parameter `'r` is defined here
@@ -62,15 +62,15 @@ LL |     type Assoc<const Q: usize>: Trait<'r, Self, Q, K = const { loop {} }>
    = note: `K` has type `&'r [Self; Q]`
 
 error: the type of the associated constant `K` must not depend on `Self`
-  --> $DIR/assoc-const-eq-param-in-ty.rs:54:52
+  --> $DIR/assoc-const-eq-param-in-ty.rs:53:52
    |
 LL |     type Assoc<const Q: usize>: Trait<'r, Self, Q, K = const { loop {} }>
    |                                                    ^ its type must not depend on `Self`
    |
    = note: `K` has type `&'r [Self; Q]`
 
 error: the type of the associated constant `K` must not depend on generic parameters
-  --> $DIR/assoc-const-eq-param-in-ty.rs:54:52
+  --> $DIR/assoc-const-eq-param-in-ty.rs:53:52
    |
 LL |     type Assoc<const Q: usize>: Trait<'r, Self, Q, K = const { loop {} }>
    |                      -                             ^ its type must not depend on the const parameter `Q`
@@ -80,7 +80,7 @@ LL |     type Assoc<const Q: usize>: Trait<'r, Self, Q, K = const { loop {} }>
    = note: `K` has type `&'r [Self; Q]`
 
 error: the type of the associated constant `K` must not depend on generic parameters
-  --> $DIR/assoc-const-eq-param-in-ty.rs:54:52
+  --> $DIR/assoc-const-eq-param-in-ty.rs:53:52
    |
 LL | trait Iface<'r>: ConstParamTy_ {
    |             -- the lifetime parameter `'r` is defined here
@@ -92,7 +92,7 @@ LL |     type Assoc<const Q: usize>: Trait<'r, Self, Q, K = const { loop {} }>
    = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 
 error: the type of the associated constant `K` must not depend on `Self`
-  --> $DIR/assoc-const-eq-param-in-ty.rs:54:52
+  --> $DIR/assoc-const-eq-param-in-ty.rs:53:52
    |
 LL |     type Assoc<const Q: usize>: Trait<'r, Self, Q, K = const { loop {} }>
    |                                                    ^ its type must not depend on `Self`
@@ -101,7 +101,7 @@ LL |     type Assoc<const Q: usize>: Trait<'r, Self, Q, K = const { loop {} }>
    = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 
 error: the type of the associated constant `K` must not depend on generic parameters
-  --> $DIR/assoc-const-eq-param-in-ty.rs:54:52
+  --> $DIR/assoc-const-eq-param-in-ty.rs:53:52
    |
 LL |     type Assoc<const Q: usize>: Trait<'r, Self, Q, K = const { loop {} }>
    |                      -                             ^ its type must not depend on the const parameter `Q`

tests/ui/associated-consts/assoc-const-eq-supertraits.rs

@@ -4,7 +4,6 @@
 //@ check-pass
 
 #![feature(
-    associated_const_equality,
     min_generic_const_args,
     adt_const_params,
     unsized_const_params,

tests/ui/associated-consts/assoc-const-eq-ty-alias-noninteracting.rs

@@ -5,7 +5,7 @@
 
 //@ check-pass
 
-#![feature(associated_const_equality, min_generic_const_args, unsized_const_params)]
+#![feature(min_generic_const_args, unsized_const_params)]
 #![allow(incomplete_features)]
 
 trait Trait: SuperTrait {

tests/ui/associated-consts/assoc-const-ty-mismatch.rs

@@ -1,5 +1,5 @@
-#![feature(associated_const_equality)]
-#![allow(unused)]
+#![feature(min_generic_const_args)]
+#![allow(incomplete_features, unused)]
 
 pub trait Foo {
     const N: usize;

tests/ui/associated-consts/assoc-const.rs

@@ -1,5 +1,5 @@
 //@ run-pass
-#![feature(associated_const_equality, min_generic_const_args)]
+#![feature(min_generic_const_args)]
 #![allow(unused, incomplete_features)]
 
 pub trait Foo {

tests/ui/associated-consts/equality-unused-issue-126729.rs

@@ -1,6 +1,6 @@
 //@ check-pass
 
-#![feature(associated_const_equality, min_generic_const_args)]
+#![feature(min_generic_const_args)]
 #![allow(incomplete_features)]
 #![deny(dead_code)]
 

tests/ui/associated-consts/issue-102335-const.rs

@@ -1,4 +1,4 @@
-#![feature(associated_const_equality, min_generic_const_args)]
+#![feature(min_generic_const_args)]
 #![allow(incomplete_features)]
 
 trait T {