1 files changed, 78 insertions, 0 deletions
diff --git a/test/std/thread/thread.mutex/thread.lock/thread.lock.guard/variadic_types.pass.cpp b/test/std/thread/thread.mutex/thread.lock/thread.lock.guard/variadic_types.pass.cpp
new file mode 100644
index 000000000000..2b06742a673e
--- /dev/null
+++ b/test/std/thread/thread.mutex/thread.lock/thread.lock.guard/variadic_types.pass.cpp
@@ -0,0 +1,78 @@
+//===----------------------------------------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// UNSUPPORTED: libcpp-has-no-threads
+// UNSUPPORTED: c++98, c++03
+
+// <mutex>
+
+// template <class Mutex>
+// class lock_guard
+// {
+// public:
+//     typedef Mutex mutex_type;
+//     ...
+// };
+
+#define _LIBCPP_ABI_VARIADIC_LOCK_GUARD
+#include <mutex>
+#include <type_traits>
+
+struct NAT {};
+
+template <class LG>
+auto test_typedef(int) -> typename LG::mutex_type;
+
+template <class LG>
+auto test_typedef(...) -> NAT;
+
+template <class LG>
+constexpr bool has_mutex_type() {
+    return !std::is_same<decltype(test_typedef<LG>(0)), NAT>::value;
+}
+
+int main()
+{
+    {
+        using T = std::lock_guard<>;
+        static_assert(!has_mutex_type<T>(), "");
+    }
+    {
+        using M1 = std::mutex;
+        using T = std::lock_guard<M1>;
+        static_assert(std::is_same<T::mutex_type, M1>::value, "");
+    }
+    {
+        using M1 = std::recursive_mutex;
+        using T = std::lock_guard<M1>;
+        static_assert(std::is_same<T::mutex_type, M1>::value, "");
+    }
+    {
+        using M1 = std::mutex;
+        using M2 = std::recursive_mutex;
+        using T = std::lock_guard<M1, M2>;
+        static_assert(!has_mutex_type<T>(), "");
+    }
+    {
+        using M1 = std::mutex;
+        using M2 = std::recursive_mutex;
+        using T = std::lock_guard<M1, M1, M2>;
+        static_assert(!has_mutex_type<T>(), "");
+    }
+    {
+        using M1 = std::mutex;
+        using T = std::lock_guard<M1, M1>;
+        static_assert(!has_mutex_type<T>(), "");
+    }
+    {
+        using M1 = std::recursive_mutex;
+        using T = std::lock_guard<M1, M1, M1>;
+        static_assert(!has_mutex_type<T>(), "");
+    }
+}