LWG Issue 2097: packaged_task constructors should be constrained

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@192544 91177308-0d34-0410-b5e6-96231b3b80d8

test/thread/thread.threads/thread.thread.class/thread.thread.constr/constr.fail.cpp

@@ -0,0 +1,26 @@
+//===----------------------------------------------------------------------===//
+//
+//                     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.
+//
+//===----------------------------------------------------------------------===//
+
+// <thread>
+
+// class thread
+//     template <class _Fp, class ..._Args,
+//         explicit thread(_Fp&& __f, _Args&&... __args);
+//  This constructor shall not participate in overload resolution 
+//       if decay<F>::type is the same type as std::thread.
+
+
+#include <thread>
+#include <cassert>
+
+int main()
+{
+    volatile std::thread t1;
+    std::thread t2 ( t1, 1, 2.0 );
+}