Test case for issue 2380

src/test/auxiliary/issue-2380.rs

@@ -0,0 +1,10 @@
+#[link(name = "a", vers = "0.0")];
+#[crate_type = "lib"];
+
+iface i<T> { }
+
+fn f<T>() -> i<T> {
+    impl <T> of i<T> for () { }
+
+    () as i::<T>
+}

src/test/run-pass/issue-2380-b.rs

@@ -0,0 +1,8 @@
+// xfail-fast
+// aux-build:issue-2380.rs
+
+use a;
+
+fn main() {
+    a::f::<()>();
+}