fix bug with defaulted move in msvc 12.0

test/optional_test_maybe_uninitialized_warning.cpp

@@ -0,0 +1,32 @@
+// Copyright (C) 2017 Andrzej Krzemienski.
+//
+// Use, modification, and distribution is subject to the Boost Software
+// License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+//
+// See http://www.boost.org/lib/optional for documentation.
+//
+// You are welcome to contact the author at:
+//  akrzemi1@gmail.com
+
+#include "boost/optional/optional.hpp"
+
+#ifdef __BORLANDC__
+#pragma hdrstop
+#endif
+
+boost::optional<int> getitem();
+
+int main(int argc, const char *[])
+{
+  boost::optional<int> a = getitem();
+  boost::optional<int> b;
+
+  if (argc > 0)
+    b = argc;
+
+  if (a != b)
+    return 1;
+
+  return 0;
+}