1 files changed, 35 insertions, 0 deletions
diff --git a/test/SemaCXX/libstdcxx_atomic_ns_hack.cpp b/test/SemaCXX/libstdcxx_atomic_ns_hack.cpp
new file mode 100644
index 0000000..4e4523f
--- /dev/null
+++ b/test/SemaCXX/libstdcxx_atomic_ns_hack.cpp
@@ -0,0 +1,35 @@
+// RUN: %clang_cc1 -fsyntax-only -std=c++11 -verify %s
+
+// libstdc++ 4.6.x contains a bug where it defines std::__atomic[0,1,2] as a
+// non-inline namespace, then selects one of those namespaces and reopens it
+// as inline, as a strange way of providing something like a using-directive.
+// Clang has an egregious hack to work around the problem, by allowing a
+// namespace to be converted from non-inline to inline in this one specific
+// case.
+
+#ifdef BE_THE_HEADER
+
+#pragma clang system_header
+
+namespace std {
+  namespace __atomic0 {
+    typedef int foobar;
+  }
+  namespace __atomic1 {
+    typedef void foobar;
+  }
+
+  inline namespace __atomic0 {}
+}
+
+#else
+
+#define BE_THE_HEADER
+#include "libstdcxx_atomic_ns_hack.cpp"
+
+std::foobar fb;
+
+using T = void; // expected-note {{here}}
+using T = std::foobar; // expected-error {{different types ('std::foobar' (aka 'int') vs 'void')}}
+
+#endif