Add a test case using associated types cross crate. Fixes #18048.

src/test/auxiliary/issue-18048-lib.rs

@@ -0,0 +1,24 @@
+// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+#![crate_type="lib"]
+#![feature(associated_types)]
+
+pub trait Bar {
+    type T;
+
+    fn get(x: Option<Self>) -> <Self as Bar>::T;
+}
+
+impl Bar for int {
+    type T = uint;
+
+    fn get(_: Option<int>) -> uint { 22 }
+}

src/test/run-pass/issue-18048.rs

@@ -0,0 +1,28 @@
+// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+// aux-build:issue-18048-lib.rs
+
+// Test that we are able to reference cross-crate traits that employ
+// associated types.
+
+#![feature(associated_types)]
+
+extern crate "issue-18048-lib" as bar;
+
+use bar::Bar;
+
+fn foo<B:Bar>(b: B) -> <B as Bar>::T {
+    Bar::get(None::<B>)
+}
+
+fn main() {
+    println!("{}", foo(3i));
+}