testsuite: Add test for #4208

Closes #4208

Author: catamorphism

src/test/auxiliary/issue-4208-cc.rs

@@ -0,0 +1,21 @@
+// Copyright 2013 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.
+
+#[link(name = "numeric",
+       vers = "0.1")];
+#[crate_type = "lib"];
+
+pub trait Trig<T> {
+    fn sin(&self) -> T;
+}
+
+pub fn sin<T:Trig<R>, R>(theta: &T) -> R { theta.sin() }
+
+pub trait Angle<T>: Trig<T> {}

src/test/run-pass/issue-4208.rs

@@ -0,0 +1,19 @@
+// Copyright 2013 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-4208-cc.rs
+// xfail-fast - Windows hates cross-crate tests
+
+extern mod numeric;
+use numeric::*;
+
+fn foo<T, A:Angle<T>>(theta: A) -> T { sin(&theta) }
+
+fn main() {}