From 91e1f24f12462b3b573a82c2355e8b803024cbab Mon Sep 17 00:00:00 2001
From: Jeffrey Seyfried <jeffrey.seyfried@gmail.com>
Date: Sat, 1 Oct 2016 07:38:47 +0000
Subject: [PATCH] Fix `module_to_string`.

---
 src/librustc_resolve/lib.rs          |  2 +-
 src/test/compile-fail/issue-36881.rs | 14 ++++++++++++++
 2 files changed, 15 insertions(+), 1 deletion(-)
 create mode 100644 src/test/compile-fail/issue-36881.rs

diff --git a/src/librustc_resolve/lib.rs b/src/librustc_resolve/lib.rs
index 0694edd235777..d1bfb7d786eb3 100644
--- a/src/librustc_resolve/lib.rs
+++ b/src/librustc_resolve/lib.rs
@@ -3534,7 +3534,7 @@ fn module_to_string(module: Module) -> String {
         } else {
             // danger, shouldn't be ident?
             names.push(token::intern("<opaque>"));
-            collect_mod(names, module);
+            collect_mod(names, module.parent.unwrap());
         }
     }
     collect_mod(&mut names, module);
diff --git a/src/test/compile-fail/issue-36881.rs b/src/test/compile-fail/issue-36881.rs
new file mode 100644
index 0000000000000..cca20e968e0c4
--- /dev/null
+++ b/src/test/compile-fail/issue-36881.rs
@@ -0,0 +1,14 @@
+// Copyright 2016 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.
+
+fn main() {
+    extern crate rand;
+    use rand::Rng; //~ ERROR unresolved import
+}