libstdc++-v3/testsuite/20_util/hash/52931.cc

   1 // { dg-options "-std=gnu++11" }
   2 // { dg-do compile }
   3
   4 // Copyright (C) 2012-2014 Free Software Foundation, Inc.
   5 //
   6 // This file is part of the GNU ISO C++ Library.  This library is free
   7 // software; you can redistribute it and/or modify it under the
   8 // terms of the GNU General Public License as published by the
   9 // Free Software Foundation; either version 3, or (at your option)
  10 // any later version.
  11 //
  12 // This library is distributed in the hope that it will be useful,
  13 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 // GNU General Public License for more details.
  16 //
  17 // You should have received a copy of the GNU General Public License
  18 // along with this library; see the file COPYING3.  If not see
  19 // <http://www.gnu.org/licenses/>.
  20
  21 #include <type_traits>
  22 #include <functional>
  23
  24 class S{}; // No hash specialization
  25
  26 template<class T>
  27 auto f(int) -> decltype(std::hash<T>(), std::true_type());
  28
  29 template<class T>
  30 auto f(...) -> decltype(std::false_type());
  31
  32 static_assert(!decltype(f<S>(0))::value, "");