Implement trait inheritance for bounded type parameters

src/test/run-pass/trait-inheritance-call-bound-inherited.rs

@@ -0,0 +1,18 @@
+trait Foo { fn f() -> int; }
+trait Bar : Foo { fn g() -> int; }
+
+struct A { x: int }
+
+impl A : Foo { fn f() -> int { 10 } }
+impl A : Bar { fn g() -> int { 20 } }
+
+// Call a function on Foo, given a T: Bar
+fn gg<T:Bar>(a: &T) -> int {
+    a.f()
+}
+
+fn main() {
+    let a = &A { x: 3 };
+    assert gg(a) == 10;
+}
+