Support Self in struct expressions and patterns

Author: petrochenkov

src/librustc_typeck/check/mod.rs

@@ -3234,16 +3234,14 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
                 }
             }
             Def::Struct(..) | Def::Union(..) | Def::TyAlias(..) |
-            Def::AssociatedTy(..) => {
+            Def::AssociatedTy(..) | Def::SelfTy(..) => {
                 match ty.sty {
                     ty::TyAdt(adt, substs) if !adt.is_enum() => {
                         Some((adt.struct_variant(), adt.did, substs))
                     }
                     _ => None,
                 }
             }
-            // Self is not supported yet.
-            Def::SelfTy(..) => None,
             _ => bug!("unexpected definition: {:?}", def)
         };
 

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

@@ -0,0 +1,47 @@
+// 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.
+
+struct S;
+
+trait Tr {
+    fn f() {
+        let s = Self {};
+        //~^ ERROR expected struct, variant or union type, found type parameter `Self`
+        let z = Self::<u8> {};
+        //~^ ERROR expected struct, variant or union type, found type parameter `Self`
+        //~| ERROR type parameters are not allowed on this type
+        match s {
+            Self { .. } => {}
+            //~^ ERROR expected struct, variant or union type, found type parameter `Self`
+        }
+    }
+}
+
+impl Tr for S {
+    fn f() {
+        let s = Self {}; // OK
+        let z = Self::<u8> {}; //~ ERROR type parameters are not allowed on this type
+        match s {
+            Self { .. } => {} // OK
+        }
+    }
+}
+
+impl S {
+    fn g() {
+        let s = Self {}; // OK
+        let z = Self::<u8> {}; //~ ERROR type parameters are not allowed on this type
+        match s {
+            Self { .. } => {} // OK
+        }
+    }
+}
+
+fn main() {}

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

@@ -0,0 +1,54 @@
+// 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.
+
+use std::ops::Add;
+
+struct S<T, U = u16> {
+    a: T,
+    b: U,
+}
+
+trait Tr {
+    fn f(&self) -> Self;
+}
+
+impl<T: Default + Add<u8, Output = T>, U: Default> Tr for S<T, U> {
+    fn f(&self) -> Self {
+        let s = Self { a: Default::default(), b: Default::default() };
+        match s {
+            Self { a, b } => Self { a: a + 1, b: b }
+        }
+    }
+}
+
+impl<T: Default, U: Default + Add<u16, Output = U>> S<T, U> {
+    fn g(&self) -> Self {
+        let s = Self { a: Default::default(), b: Default::default() };
+        match s {
+            Self { a, b } => Self { a: a, b: b + 1 }
+        }
+    }
+}
+
+impl S<u8> {
+    fn new() -> Self {
+        Self { a: 0, b: 1 }
+    }
+}
+
+fn main() {
+    let s0 = S::new();
+    let s1 = s0.f();
+    assert_eq!(s1.a, 1);
+    assert_eq!(s1.b, 0);
+    let s2 = s0.g();
+    assert_eq!(s2.a, 0);
+    assert_eq!(s2.b, 1);
+}