Rename feature gate

src/librustc_feature/active.rs

@@ -528,7 +528,7 @@ declare_features! (
     (active, cfg_sanitize, "1.41.0", Some(39699), None),
 
     /// Allows using `&mut` in constant functions.
-    (active, const_fn_mut_refs, "1.41.0", None, None),
+    (active, const_mut_refs, "1.41.0", Some(57349), None),
 
     // -------------------------------------------------------------------------
     // feature-group-end: actual feature gates

src/librustc_mir/transform/qualify_min_const_fn.rs

@@ -81,7 +81,7 @@ fn check_ty(tcx: TyCtxt<'tcx>, ty: Ty<'tcx>, span: Span, fn_def_id: DefId) -> Mc
     for ty in ty.walk() {
         match ty.kind {
             ty::Ref(_, _, hir::Mutability::Mutable) => {
-                if !tcx.features().const_fn_mut_refs {
+                if !tcx.features().const_mut_refs {
                     return Err((
                         span,
                         "mutable references in const fn are unstable".into(),

src/libsyntax_pos/symbol.rs

@@ -203,13 +203,13 @@ symbols! {
         const_constructor,
         const_extern_fn,
         const_fn,
-        const_fn_mut_refs,
         const_fn_union,
         const_generics,
         const_if_match,
         const_indexing,
         const_in_array_repeat_expressions,
         const_let,
+        const_mut_refs,
         const_panic,
         const_raw_ptr_deref,
         const_raw_ptr_to_usize_cast,

src/test/ui/consts/const_fn_mut_refs.rs

@@ -1,6 +1,6 @@
 // run-pass
 
-#![feature(const_fn_mut_refs)]
+#![feature(const_mut_refs)]
 
 struct Foo {
     x: i32