libstdc++-v3/testsuite/std/ranges/iota/iterator.cc

   1 // Copyright (C) 2020-2022 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++2a" }
  19 // { dg-do compile { target c++2a } }
  20
  21 #include <ranges>
  22
  23 auto i = std::ranges::iota_view<int>{}.begin();
  24 static_assert( std::three_way_comparable<decltype(i)> );
  25
  26 struct Inc {
  27   Inc& operator++();
  28   Inc operator++(int);
  29   friend long operator-(Inc, Inc);
  30 };
  31 static_assert( ! std::three_way_comparable<Inc> );
  32
  33 // Instantiating iterator type must be valid despite !three_way_comparable<Inc>
  34 auto j = std::ranges::iota_view<Inc>{}.begin();
  35 static_assert( ! std::three_way_comparable<decltype(j)> );