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 1/2] 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 @@ fn lookup_candidates<FilterFn>(&mut self,
                     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));
+                        }
                     }
                 }
             })

From 9ffe1c9fba7d1327b1836188f76ca430e0333690 Mon Sep 17 00:00:00 2001
From: Jeffrey Seyfried <jeffrey.seyfried@gmail.com>
Date: Wed, 29 Jun 2016 00:18:07 +0000
Subject: [PATCH 2/2] Add regression test

---
 .../compile-fail/auxiliary/recursive_reexports.rs | 13 +++++++++++++
 src/test/compile-fail/recursive-reexports.rs      | 15 +++++++++++++++
 2 files changed, 28 insertions(+)
 create mode 100644 src/test/compile-fail/auxiliary/recursive_reexports.rs
 create mode 100644 src/test/compile-fail/recursive-reexports.rs

diff --git a/src/test/compile-fail/auxiliary/recursive_reexports.rs b/src/test/compile-fail/auxiliary/recursive_reexports.rs
new file mode 100644
index 00000000000..1186e3d62f7
--- /dev/null
+++ b/src/test/compile-fail/auxiliary/recursive_reexports.rs
@@ -0,0 +1,13 @@
+// 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.
+
+pub mod foo {
+    pub use foo;
+}
diff --git a/src/test/compile-fail/recursive-reexports.rs b/src/test/compile-fail/recursive-reexports.rs
new file mode 100644
index 00000000000..6fd52beeec6
--- /dev/null
+++ b/src/test/compile-fail/recursive-reexports.rs
@@ -0,0 +1,15 @@
+// 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.
+
+// aux-build:recursive_reexports.rs
+
+fn f() -> recursive_reexports::S {} //~ ERROR undeclared
+
+fn main() {}