libstdc++-v3/testsuite/18_support/comparisons/common/1.cc

   1 // Copyright (C) 2019-2021 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 <compare>
  22
  23 template<typename Cat, typename... T>
  24 constexpr bool check()
  25 {
  26   return std::same_as<Cat, std::common_comparison_category_t<T...>>;
  27 }
  28
  29 using std::partial_ordering;
  30 using std::weak_ordering;
  31 using std::strong_ordering;
  32
  33 static_assert(check<strong_ordering>());
  34 static_assert(check<void, int>());
  35 static_assert(check<void, int, int>());
  36 static_assert(check<void, weak_ordering, int>());
  37 static_assert(check<void, int, partial_ordering>());
  38 static_assert(check<partial_ordering, partial_ordering>());
  39 static_assert(check<partial_ordering, weak_ordering, partial_ordering>());
  40
  41 using PO = std::partial_ordering;
  42 using WO = std::weak_ordering;
  43 using SO = std::strong_ordering;
  44
  45 static_assert(check<PO, SO, PO, SO, SO>());
  46 static_assert(check<PO, SO, PO, SO, WO>());
  47 static_assert(check<WO, SO, WO, SO, WO>());
  48 static_assert(check<SO, SO, SO, SO, SO>());