Rollup merge of rust-lang#56366 - alexreg:stabilise-self_in_typedefs, r=Centril

Stabilize self_in_typedefs feature

[**Tracking Issue**](rust-lang#49303)

r? @Centril

Author: kennytm

src/doc/unstable-book/src/language-features/self-in-typedefs.md

@@ -2373,13 +2373,9 @@ impl<'a, 'crateloader: 'a> Resolver<'a, 'crateloader> {
         self.with_current_self_item(item, |this| {
             this.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
                 let item_def_id = this.definitions.local_def_id(item.id);
-                if this.session.features_untracked().self_in_typedefs {
-                    this.with_self_rib(Def::SelfTy(None, Some(item_def_id)), |this| {
-                        visit::walk_item(this, item);
-                    });
-                } else {
+                this.with_self_rib(Def::SelfTy(None, Some(item_def_id)), |this| {
                     visit::walk_item(this, item);
-                }
+                });
             });
         });
     }
@@ -3185,16 +3181,8 @@ impl<'a, 'crateloader: 'a> Resolver<'a, 'crateloader> {
             if is_self_type(path, ns) {
                 __diagnostic_used!(E0411);
                 err.code(DiagnosticId::Error("E0411".into()));
-                let available_in = if this.session.features_untracked().self_in_typedefs {
-                    "impls, traits, and type definitions"
-                } else {
-                    "traits and impls"
-                };
-                err.span_label(span, format!("`Self` is only available in {}", available_in));
-                if this.current_self_item.is_some() && nightly_options::is_nightly_build() {
-                    err.help("add #![feature(self_in_typedefs)] to the crate attributes \
-                              to enable");
-                }
+                err.span_label(span, format!("`Self` is only available in impls, traits, \
+                                              and type definitions"));
                 return (err, Vec::new());
             }
             if is_self_value(path, ns) {

src/librustc_resolve/lib.rs

@@ -462,9 +462,6 @@ declare_features! (
     // Allows `use x::y;` to resolve through `self::x`, not just `::x`
     (active, uniform_paths, "1.30.0", Some(53130), None),
 
-    // Allows `Self` in type definitions
-    (active, self_in_typedefs, "1.30.0", Some(49303), None),
-
     // Allows unsized rvalues at arguments and parameters
     (active, unsized_locals, "1.30.0", Some(48055), None),
 
@@ -675,21 +672,23 @@ declare_features! (
     (accepted, extern_prelude, "1.30.0", Some(44660), None),
     // Parentheses in patterns
     (accepted, pattern_parentheses, "1.31.0", Some(51087), None),
-    // Allows the definition of `const fn` functions.
+    // Allows the definition of `const fn` functions
     (accepted, min_const_fn, "1.31.0", Some(53555), None),
     // Scoped lints
     (accepted, tool_lints, "1.31.0", Some(44690), None),
     // impl<I:Iterator> Iterator for &mut Iterator
     // impl Debug for Foo<'_>
     (accepted, impl_header_lifetime_elision, "1.31.0", Some(15872), None),
-    // `extern crate foo as bar;` puts `bar` into extern prelude.
+    // `extern crate foo as bar;` puts `bar` into extern prelude
     (accepted, extern_crate_item_prelude, "1.31.0", Some(55599), None),
     // Allows use of the :literal macro fragment specifier (RFC 1576)
     (accepted, macro_literal_matcher, "1.31.0", Some(35625), None),
     // Use `?` as the Kleene "at most one" operator
     (accepted, macro_at_most_once_rep, "1.32.0", Some(48075), None),
-    // Self struct constructor  (RFC 2302)
+    // `Self` struct constructor (RFC 2302)
     (accepted, self_struct_ctor, "1.32.0", Some(51994), None),
+    // `Self` in type definitions (RFC 2300)
+    (accepted, self_in_typedefs, "1.32.0", Some(49303), None),
 );
 
 // If you change this, please modify `src/doc/unstable-book` as well. You must

src/libsyntax/feature_gate.rs

@@ -9,12 +9,11 @@
 // except according to those terms.
 
 // run-pass
-#![allow(unions_with_drop_fields)]
 
-#![feature(self_in_typedefs)]
 #![feature(untagged_unions)]
 
 #![allow(dead_code)]
+#![allow(unions_with_drop_fields)]
 
 enum A<'a, T: 'a>
 where

src/test/run-pass/self/self-in-typedefs.rs

@@ -2,7 +2,7 @@ error[E0411]: cannot find type `Self` in this scope
   --> $DIR/E0411.rs:12:6
    |
 LL |     <Self>::foo; //~ ERROR E0411
-   |      ^^^^ `Self` is only available in traits and impls
+   |      ^^^^ `Self` is only available in impls, traits, and type definitions
 
 error: aborting due to previous error
 

src/test/ui/error-codes/E0411.stderr

@@ -12,6 +12,7 @@
 
 struct Foo<Self>(Self);
 //~^ ERROR expected identifier, found keyword `Self`
+//~^^ ERROR E0392
 
 trait Bar<Self> {}
 //~^ ERROR expected identifier, found keyword `Self`

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

@@ -5,10 +5,19 @@ LL | struct Foo<Self>(Self);
    |            ^^^^ expected identifier, found keyword
 
 error: expected identifier, found keyword `Self`
-  --> $DIR/issue-36638.rs:16:11
+  --> $DIR/issue-36638.rs:17:11
    |
 LL | trait Bar<Self> {}
    |           ^^^^ expected identifier, found keyword
 
-error: aborting due to 2 previous errors
+error[E0392]: parameter `Self` is never used
+  --> $DIR/issue-36638.rs:13:12
+   |
+LL | struct Foo<Self>(Self);
+   |            ^^^^ unused type parameter
+   |
+   = help: consider removing `Self` or using a marker such as `std::marker::PhantomData`
+
+error: aborting due to 3 previous errors
 
+For more information about this error, try `rustc --explain E0392`.

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

@@ -2,7 +2,7 @@ error[E0411]: cannot find type `Self` in this scope
   --> $DIR/issue-24968.rs:11:11
    |
 LL | fn foo(_: Self) {
-   |           ^^^^ `Self` is only available in traits and impls
+   |           ^^^^ `Self` is only available in impls, traits, and type definitions
 
 error: aborting due to previous error
 

src/test/ui/issues/issue-36638.rs

@@ -2,7 +2,7 @@ error[E0411]: expected trait, found self type `Self`
   --> $DIR/resolve-self-in-impl-2.rs:14:6
    |
 LL | impl Self for S {} //~ ERROR expected trait, found self type `Self`
-   |      ^^^^ `Self` is only available in traits and impls
+   |      ^^^^ `Self` is only available in impls, traits, and type definitions
 
 error[E0405]: cannot find trait `N` in `Self`
   --> $DIR/resolve-self-in-impl-2.rs:15:12