Replace type_alias_impl_trait by min_type_alias_impl_trait with no actual changes in behaviour

This makes `type_alias_impl_trait` not actually do anything anymore

Author: oli-obk

compiler/rustc_ast_passes/src/feature_gate.rs

@@ -279,7 +279,7 @@ impl<'a> PostExpansionVisitor<'a> {
                 if let ast::TyKind::ImplTrait(..) = ty.kind {
                     gate_feature_post!(
                         &self.vis,
-                        type_alias_impl_trait,
+                        min_type_alias_impl_trait,
                         ty.span,
                         "`impl Trait` in type aliases is unstable"
                     );

compiler/rustc_feature/src/active.rs

@@ -638,6 +638,9 @@ declare_features! (
     /// Allows `pub` on `macro_rules` items.
     (active, pub_macro_rules, "1.52.0", Some(78855), None),
 
+    /// Allows the use of type alias impl trait in function return positions
+    (active, min_type_alias_impl_trait, "1.52.0", Some(63063), None),
+
     /// Allows associated types in inherent impls.
     (active, inherent_associated_types, "1.52.0", Some(8995), None),
 
@@ -670,6 +673,7 @@ pub const INCOMPLETE_FEATURES: &[Symbol] = &[
     sym::capture_disjoint_fields,
     sym::const_generics_defaults,
     sym::inherent_associated_types,
+    sym::type_alias_impl_trait,
 ];
 
 /// Some features are not allowed to be used together at the same time, if

compiler/rustc_feature/src/removed.rs

@@ -106,7 +106,7 @@ declare_features! (
      Some("subsumed by `.await` syntax")),
     /// Allows defining `existential type`s.
     (removed, existential_type, "1.38.0", Some(63063), None,
-     Some("removed in favor of `#![feature(type_alias_impl_trait)]`")),
+     Some("removed in favor of `#![feature(min_type_alias_impl_trait)]`")),
     /// Allows using the macros:
     /// + `__diagnostic_used`
     /// + `__register_diagnostic`

compiler/rustc_span/src/symbol.rs

@@ -736,6 +736,7 @@ symbols! {
         min_const_generics,
         min_const_unsafe_fn,
         min_specialization,
+        min_type_alias_impl_trait,
         minnumf32,
         minnumf64,
         mips_target_feature,

library/alloc/src/lib.rs

@@ -142,7 +142,8 @@
 #![feature(alloc_layout_extra)]
 #![feature(trusted_random_access)]
 #![feature(try_trait)]
-#![feature(type_alias_impl_trait)]
+#![cfg_attr(bootstrap, feature(type_alias_impl_trait))]
+#![cfg_attr(not(bootstrap), feature(min_type_alias_impl_trait))]
 #![feature(associated_type_bounds)]
 #![feature(slice_group_by)]
 #![feature(decl_macro)]

src/test/rustdoc-ui/error-in-impl-trait/trait-alias-closure.rs

@@ -1,5 +1,5 @@
 // check-pass
-#![feature(type_alias_impl_trait)]
+#![feature(min_type_alias_impl_trait)]
 
 pub trait ValidTrait {}
 type ImplTrait = impl ValidTrait;

src/test/rustdoc-ui/error-in-impl-trait/trait-alias.rs

@@ -1,5 +1,5 @@
 // check-pass
-#![feature(type_alias_impl_trait)]
+#![feature(min_type_alias_impl_trait)]
 
 pub trait ValidTrait {}
 type ImplTrait = impl ValidTrait;

src/test/rustdoc/auxiliary/issue-73061.rs

@@ -1,6 +1,6 @@
 //edition:2018
 
-#![feature(type_alias_impl_trait)]
+#![feature(min_type_alias_impl_trait)]
 
 pub trait Foo {
     type X: std::future::Future<Output = ()>;

src/test/rustdoc/impl-trait-alias.rs

@@ -1,4 +1,4 @@
-#![feature(type_alias_impl_trait)]
+#![feature(min_type_alias_impl_trait)]
 
 trait MyTrait {}
 impl MyTrait for i32 {}

src/test/rustdoc/return-impl-trait.rs

@@ -1,4 +1,4 @@
-#![feature(type_alias_impl_trait)]
+#![feature(min_type_alias_impl_trait)]
 
 pub trait Backend {}