Add test accidentally not added in revision r239121

	* testsuite/20_util/enable_shared_from_this/members/weak_from_this.cc:
	New test.

From-SVN: r239896

libstdc++-v3/ChangeLog

+2016-08-31  Jonathan Wakely  <jwakely@redhat.com>
+
+	* testsuite/20_util/enable_shared_from_this/members/weak_from_this.cc:
+	New test.
+
 2016-08-30  Ville Voutilainen  <ville.voutilainen@gmail.com>
 
 	PR libstdc++/77395

libstdc++-v3/testsuite/20_util/enable_shared_from_this/members/weak_from_this.cc

+// Copyright (C) 2015-2016 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-options "-std=gnu++17" }
+
+#include <memory>
+#include <testsuite_hooks.h>
+
+#if __cpp_lib_enable_shared_from_this < 201603
+# error "__cpp_lib_enable_shared_from_this < 201603"
+#endif
+
+struct X : public std::enable_shared_from_this<X> { };
+
+void
+test01()
+{
+  std::shared_ptr<X> sp(new X);
+  auto wp1 = sp->weak_from_this();
+  std::weak_ptr<X> wp2 = sp;
+
+  std::owner_less<> less;
+  VERIFY( !less(wp1, wp2) && !less(wp2, wp1) );
+  VERIFY( !less(wp1, wp2) && !less(wp2, wp1) );
+}
+
+int
+main()
+{
+  test01();
+}