rollup merge of #20665: nikomatsakis/assoc-types-method-dispatch-projection

Conflicts:
	src/librustc/middle/ty.rs

src/test/run-pass/method-projection.rs

@@ -0,0 +1,78 @@
+// Copyright 2014 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.
+
+// Test that we can use method notation to call methods based on a
+// projection bound from a trait. Issue #20469.
+
+///////////////////////////////////////////////////////////////////////////
+
+trait MakeString {
+    fn make_string(&self) -> String;
+}
+
+impl MakeString for int {
+    fn make_string(&self) -> String {
+        format!("{}", *self)
+    }
+}
+
+impl MakeString for uint {
+    fn make_string(&self) -> String {
+        format!("{}", *self)
+    }
+}
+
+///////////////////////////////////////////////////////////////////////////
+
+trait Foo {
+    type F: MakeString;
+
+    fn get(&self) -> &Self::F;
+}
+
+fn foo<F:Foo>(f: &F) -> String {
+    f.get().make_string()
+}
+
+///////////////////////////////////////////////////////////////////////////
+
+struct SomeStruct {
+    field: int,
+}
+
+impl Foo for SomeStruct {
+    type F = int;
+
+    fn get(&self) -> &int {
+        &self.field
+    }
+}
+
+///////////////////////////////////////////////////////////////////////////
+
+struct SomeOtherStruct {
+    field: uint,
+}
+
+impl Foo for SomeOtherStruct {
+    type F = uint;
+
+    fn get(&self) -> &uint {
+        &self.field
+    }
+}
+
+fn main() {
+    let x = SomeStruct { field: 22 };
+    assert_eq!(foo(&x), format!("22"));
+
+    let x = SomeOtherStruct { field: 44 };
+    assert_eq!(foo(&x), format!("44"));
+}