libstdc++-v3/testsuite/20_util/as_const/1.cc

   1 // Copyright (C) 2016-2017 Free Software Foundation, Inc.
   2 //
   3 // This file is part of the GNU ISO C++ Library.  This library is free
   4 // software; you can redistribute it and/or modify it under the
   5 // terms of the GNU General Public License as published by the
   6 // Free Software Foundation; either version 3, or (at your option)
   7 // any later version.
   8
   9 // This library is distributed in the hope that it will be useful,
  10 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 // GNU General Public License for more details.
  13
  14 // You should have received a copy of the GNU General Public License along
  15 // with this library; see the file COPYING3.  If not see
  16 // <http://www.gnu.org/licenses/>.
  17
  18 // { dg-options "-std=gnu++17" }
  19 // { dg-do compile }
  20
  21 #include <utility>
  22
  23 #if __cpp_lib_as_const != 201510
  24 # error "__cpp_lib_as_const != 201510"
  25 #endif
  26
  27 int i;
  28 constexpr auto& ci = std::as_const(i);
  29 static_assert( &i == &ci );
  30 static_assert( std::is_same_v<decltype(std::as_const(i)), const int&> );