Auto merge of #39282 - petrochenkov:selfstab, r=nikomatsakis

Stabilize Self and associated types in struct expressions and patterns

Rebase of https://github.com/rust-lang/rust/pull/37734
Closes https://github.com/rust-lang/rust/issues/37544
r? @nikomatsakis

src/librustc_typeck/check/mod.rs

@@ -3306,16 +3306,6 @@ pub fn check_struct_path(&self,
             }
             Def::Struct(..) | Def::Union(..) | Def::TyAlias(..) |
             Def::AssociatedTy(..) | Def::SelfTy(..) => {
-                match def {
-                    Def::AssociatedTy(..) | Def::SelfTy(..)
-                            if !self.tcx.sess.features.borrow().more_struct_aliases => {
-                        emit_feature_err(&self.tcx.sess.parse_sess,
-                                         "more_struct_aliases", path_span, GateIssue::Language,
-                                         "`Self` and associated types in struct \
-                                          expressions and patterns are unstable");
-                    }
-                    _ => {}
-                }
                 match ty.sty {
                     ty::TyAdt(adt, substs) if !adt.is_enum() => {
                         Some((adt.struct_variant(), adt.did, substs))

src/libsyntax/feature_gate.rs

@@ -297,10 +297,6 @@ pub fn new() -> Features {
     // The #![windows_subsystem] attribute
     (active, windows_subsystem, "1.14.0", Some(37499)),
 
-    // Allows using `Self` and associated types in struct expressions and patterns.
-    (active, more_struct_aliases, "1.14.0", Some(37544)),
-
-
     // Allows #[link(..., cfg(..))]
     (active, link_cfg, "1.14.0", Some(37406)),
 
@@ -381,6 +377,8 @@ pub fn new() -> Features {
     // Allows `..` in tuple (struct) patterns
     (accepted, dotdot_in_tuple_patterns, "1.14.0", Some(33627)),
     (accepted, item_like_imports, "1.14.0", Some(35120)),
+    // Allows using `Self` and associated types in struct expressions and patterns.
+    (accepted, more_struct_aliases, "1.14.0", Some(37544)),
 );
 // (changing above list without updating src/doc/reference.md makes @cmr sad)
 

src/test/compile-fail/struct-path-associated-type.rs

@@ -8,8 +8,6 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-#![feature(more_struct_aliases)]
-
 struct S;
 
 trait Tr {

src/test/compile-fail/struct-path-self-feature-gate.rs

-// Copyright 2016 The Rust Project Developers. See the COPYRIGHT
-// file at the top-level directory of this distribution and at
-// http://rust-lang.org/COPYRIGHT.
-//
-// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
-// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
-// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
-// option. This file may not be copied, modified, or distributed
-// except according to those terms.
-
-// gate-test-more_struct_aliases
-
-struct S;
-
-trait Tr {
-    type A;
-}
-
-fn f<T: Tr<A = S>>() {
-    let _ = T::A {};
-    //~^ ERROR `Self` and associated types in struct expressions and patterns are unstable
-}
-
-impl S {
-    fn f() {
-        let _ = Self {};
-        //~^ ERROR `Self` and associated types in struct expressions and patterns are unstable
-    }
-}
-
-fn main() {}

src/test/compile-fail/struct-path-self-type-mismatch.rs

@@ -8,8 +8,6 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-#![feature(more_struct_aliases)]
-
 struct Foo<A> { inner: A }
 
 trait Bar { fn bar(); }

src/test/compile-fail/struct-path-self.rs

@@ -8,8 +8,6 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-#![feature(more_struct_aliases)]
-
 struct S;
 
 trait Tr {

src/test/run-pass/struct-path-associated-type.rs

@@ -8,8 +8,6 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-#![feature(more_struct_aliases)]
-
 struct S<T, U = u16> {
     a: T,
     b: U,

src/test/run-pass/struct-path-self.rs

@@ -8,8 +8,6 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-#![feature(more_struct_aliases)]
-
 use std::ops::Add;
 
 struct S<T, U = u16> {