From 232783c9148045e811034985ff7ccbb1520a7a24 Mon Sep 17 00:00:00 2001
From: Jeffrey Seyfried <jeffrey.seyfried@gmail.com>
Date: Tue, 28 Jun 2016 23:03:56 +0000
Subject: [PATCH] Fix infinite loop on recursive module exports in an extern
 crate

---
 src/librustc_resolve/lib.rs | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/librustc_resolve/lib.rs b/src/librustc_resolve/lib.rs
index 8ffa95ec7e9..f983646479b 100644
--- a/src/librustc_resolve/lib.rs
+++ b/src/librustc_resolve/lib.rs
@@ -3194,7 +3194,9 @@ impl<'a> Resolver<'a> {
                     if !in_module_is_extern || name_binding.vis == ty::Visibility::Public {
                         // add the module to the lookup
                         let is_extern = in_module_is_extern || name_binding.is_extern_crate();
-                        worklist.push((module, path_segments, is_extern));
+                        if !worklist.iter().any(|&(m, _, _)| m.def == module.def) {
+                            worklist.push((module, path_segments, is_extern));
+                        }
                     }
                 }
             })