From 5b8a486b9eb32883d6c32c6c4f9cbb8fade3c147 Mon Sep 17 00:00:00 2001
From: Johannes Oertel <johannes.oertel@uni-due.de>
Date: Tue, 5 May 2015 23:52:50 +0200
Subject: [PATCH] Add regression test for #21177

Closes #21177.
---
 src/test/compile-fail/issue-21177.rs | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)
 create mode 100644 src/test/compile-fail/issue-21177.rs

diff --git a/src/test/compile-fail/issue-21177.rs b/src/test/compile-fail/issue-21177.rs
new file mode 100644
index 00000000000..5ad9a12362d
--- /dev/null
+++ b/src/test/compile-fail/issue-21177.rs
@@ -0,0 +1,19 @@
+// Copyright 2015 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.
+
+trait Trait {
+    type A;
+    type B;
+}
+
+fn foo<T: Trait<A = T::B>>() { }
+//~^ ERROR: unsupported cyclic reference between types/traits detected
+
+fn main() { }