Permit method calls based on where clauses.

src/test/run-pass/method-where-clause.rs

@@ -0,0 +1,42 @@
+// 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
+// where clause type, and not only type parameters.
+
+trait Foo {
+    fn foo(&self) -> int;
+}
+
+impl Foo for Option<int>
+{
+    fn foo(&self) -> int {
+        self.unwrap_or(22)
+    }
+}
+
+impl Foo for Option<uint>
+{
+    fn foo(&self) -> int {
+        self.unwrap_or(22) as int
+    }
+}
+
+fn check<T>(x: Option<T>) -> (int, int)
+    where Option<T> : Foo
+{
+    let y: Option<T> = None;
+    (x.foo(), y.foo())
+}
+
+fn main() {
+    assert_eq!(check(Some(23u)), (23i, 22i));
+    assert_eq!(check(Some(23i)), (23i, 22i));
+}