rustc: Implement generic cross-crate trait inheritance

src/test/run-pass/trait-inheritance-overloading.rs

@@ -0,0 +1,21 @@
+trait MyNum : Add<self,self>, Sub<self,self>, Mul<self,self> {
+}
+
+impl int : MyNum {
+    pure fn add(other: &int) -> int { self + *other }
+    pure fn sub(other: &int) -> int { self - *other }
+    pure fn mul(other: &int) -> int { self * *other }
+}
+
+fn f<T:Copy MyNum>(x: T, y: T) -> (T, T, T) {
+    return (x + y, x - y, x * y);
+}
+
+fn main() {
+    let (x, y) = (3, 5);
+    let (a, b, c) = f(x, y);
+    assert a == 8;
+    assert b == -2;
+    assert c == 15;
+}
+