Test case for issue #718.

src/test/run-pass/issue-718.rs

+//xfail-stage0
+//xfail-stage1
+//xfail-stage2
+
+fn main() {
+
+    obj a() {
+        fn foo() -> int {
+            ret 2;
+        }
+    }
+
+    auto my_a = a();
+
+    auto my_b = obj() {
+        with my_a
+    };
+
+    assert (my_b.foo() == 2);
+
+    auto my_c = obj() {
+        with my_b
+    };
+
+    assert (my_c.foo() == 2);
+}
+