libstdc++-v3/testsuite/23_containers/array/requirements/non_default_constructible.cc

   1 // { dg-do compile { target c++11 } }
   2
   3 // Copyright (C) 2012-2016 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 <array>
  21 #include <typeindex>
  22 #include <typeinfo>
  23
  24 template < typename ...Types >
  25 union super_union;
  26
  27 template < >
  28 union super_union<>
  29 {
  30   static  auto optioned_types() -> std::array<std::type_index, 0>
  31   { return std::array<std::type_index, 0>{ {} }; }
  32 };
  33
  34 template < typename Head, typename ...Tail >
  35 union super_union<Head, Tail...>
  36 {
  37   static
  38   auto optioned_types() -> std::array<std::type_index, 1 + sizeof...(Tail)>
  39   {
  40     using std::type_index;
  41
  42     return { {type_index(typeid(Head)), type_index(typeid(Tail))...} };
  43   }
  44
  45   Head                  data;
  46   super_union<Tail...>  rest;
  47 };