PR79114 use decayed type in std::throw_with_nested assertion

	PR libstdc++/79114
	* libsupc++/nested_exception.h (throw_with_nested): Use decay instead
	of remove_reference.
	* testsuite/18_support/nested_exception/79114.cc: New test.

From-SVN: r244531

libstdc++-v3/ChangeLog

+2017-01-17  Jonathan Wakely  <jwakely@redhat.com>
+
+	PR libstdc++/79114
+	* libsupc++/nested_exception.h (throw_with_nested): Use decay instead
+	of remove_reference.
+	* testsuite/18_support/nested_exception/79114.cc: New test.
+
 2017-01-17  Jakub Jelinek  <jakub@redhat.com>
 
 	PR other/79046

libstdc++-v3/libsupc++/nested_exception.h

@@ -111,7 +111,7 @@ namespace std
     inline void
     throw_with_nested(_Tp&& __t)
     {
-      using _Up = typename remove_reference<_Tp>::type;
+      using _Up = typename decay<_Tp>::type;
       using _CopyConstructible
 	= __and_<is_copy_constructible<_Up>, is_move_constructible<_Up>>;
       static_assert(_CopyConstructible::value,

libstdc++-v3/testsuite/18_support/nested_exception/79114.cc

+// Copyright (C) 2017 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License along
+// with this library; see the file COPYING3.  If not see
+// <http://www.gnu.org/licenses/>.
+
+// { dg-do compile { target c++11 } }
+
+#include <exception>
+
+void
+test01()
+{
+  std::throw_with_nested("");
+  std::throw_with_nested(test01);
+}