PR libstdc++/87538 Verify fix for std::experimental::not_fn

	PR libstdc++/87538
	* testsuite/experimental/functional/87538.cc: New test.

From-SVN: r264922

libstdc++-v3/ChangeLog

 2018-10-08  Jonathan Wakely  <jwakely@redhat.com>
 
 	PR libstdc++/87538
+	* testsuite/experimental/functional/87538.cc: New test.
+
+	PR libstdc++/87538
 	* include/std/functional (_Not_fn::operator()): Check value of
 	__is_nothrow_invocable as well.
 	* testsuite/20_util/function_objects/not_fn/87538.cc: New test.

libstdc++-v3/testsuite/experimental/functional/87538.cc

+// Copyright (C) 2018 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 run { target c++14 } }
+
+#include <experimental/functional>
+#include <testsuite_hooks.h>
+
+struct N {
+  int operator()(int i) { if (i == 0) throw -1; return i; }
+};
+
+void
+test01()
+{
+  N n;
+  auto not_n = std::experimental::not_fn(n);
+  static_assert( !noexcept(not_n(1)), "can throw" );
+  VERIFY(not_n(1) == 0);
+  int exception = 0;
+  try {
+    not_n(0);
+  }
+  catch (int e) {
+    exception = e;
+  }
+  VERIFY(exception == -1);
+}
+
+int
+main()
+{
+  test01();
+}