libstdc++-v3/testsuite/experimental/optional/constexpr/nullopt.cc

   1 // { dg-do compile { target c++14 } }
   2
   3 // Copyright (C) 2013-2024 Free Software Foundation, Inc.
   4 //
   5 // This file is part of the GNU ISO C++ Library.  This library is free
   6 // software; you can redistribute it and/or modify it under the
   7 // terms of the GNU General Public License as published by the
   8 // Free Software Foundation; either version 3, or (at your option)
   9 // any later version.
  10
  11 // This library is distributed in the hope that it will be useful,
  12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 // GNU General Public License for more details.
  15
  16 // You should have received a copy of the GNU General Public License along
  17 // with this library; see the file COPYING3.  If not see
  18 // <http://www.gnu.org/licenses/>.
  19
  20 #include <experimental/optional>
  21 #include <testsuite_hooks.h>
  22
  23 int main()
  24 {
  25   // [20.5.6] Disengaged state indicator
  26   static_assert( std::is_same<decltype(std::experimental::nullopt), const std::experimental::nullopt_t>(), "" );
  27   static_assert( std::is_empty<std::experimental::nullopt_t>(), "" );
  28   static_assert( __is_literal_type(std::experimental::nullopt_t), "" );
  29   static_assert( !std::is_default_constructible<std::experimental::nullopt_t>(), "" );
  30
  31   {
  32     constexpr std::experimental::optional<int> o = std::experimental::nullopt;
  33     static_assert( !o, "" );
  34   }
  35
  36   {
  37     constexpr std::experimental::optional<int> o = { std::experimental::nullopt };
  38     static_assert( !o, "" );
  39   }
  40
  41   {
  42     constexpr std::experimental::optional<int> o { std::experimental::nullopt };
  43     static_assert( !o, "" );
  44   }
  45 }