libstdc++-v3/testsuite/18_support/comparisons/categories/zero_neg.cc

   1 // Copyright (C) 2020-2021 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 // C++20 [cmp.categories.pre]
  24 // "an argument other than a literal 0 is undefined"
  25
  26 void
  27 test01()
  28 {
  29   std::partial_ordering::equivalent == 0; // OK
  30   std::weak_ordering::equivalent == 0;    // OK
  31   std::strong_ordering::equivalent == 0;  // OK
  32
  33   std::partial_ordering::equivalent == 1; // { dg-error "invalid conversion" }
  34   std::weak_ordering::equivalent == 1;    // { dg-error "invalid conversion" }
  35   std::strong_ordering::equivalent == 1;  // { dg-error "invalid conversion" }
  36
  37   constexpr void* p = nullptr;
  38   std::partial_ordering::equivalent == p; // { dg-error "invalid conversion" }
  39   std::weak_ordering::equivalent == p;    // { dg-error "invalid conversion" }
  40   std::strong_ordering::equivalent == p;  // { dg-error "invalid conversion" }
  41
  42   // Ideally these would be ill-formed, but the current code accepts it.
  43   std::partial_ordering::equivalent == nullptr;
  44   std::weak_ordering::equivalent == nullptr;
  45   std::strong_ordering::equivalent == nullptr;
  46 }