Implement trait inheritance for bounded type parameters

src/test/run-pass/trait-inheritance-multiple-inheritors.rs

@@ -0,0 +1,20 @@
+trait A { fn a(&self) -> int; }
+trait B: A { fn b(&self) -> int; }
+trait C: A { fn c(&self) -> int; }
+
+struct S { bogus: () }
+
+impl S: A { fn a(&self) -> int { 10 } }
+impl S: B { fn b(&self) -> int { 20 } }
+impl S: C { fn c(&self) -> int { 30 } }
+
+// Both B and C inherit from A
+fn f<T: B C>(x: &T) {
+    assert x.a() == 10;
+    assert x.b() == 20;
+    assert x.c() == 30;
+}
+
+fn main() {
+    f(&S { bogus: () })
+}