libstdc++-v3/testsuite/std/concepts/concepts.lang/concept.swappable/swappable_with.cc

   1 // Copyright (C) 2019-2023 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 <concepts>
  22
  23 static_assert( std::swappable_with<int&, int&> );
  24 static_assert( ! std::swappable_with<int, int> );
  25 static_assert( ! std::swappable_with<int*, int*> );
  26 static_assert( ! std::swappable_with<int&, const int&> );
  27 static_assert( ! std::swappable_with<const int&, const int&> );
  28 static_assert( ! std::swappable_with<int&, long&> );
  29
  30 namespace N1
  31 {
  32   struct Immovable
  33   {
  34     Immovable() = default;
  35     Immovable(Immovable&&) = delete;
  36   };
  37 }
  38 static_assert( ! std::swappable_with<N1::Immovable&, N1::Immovable&> );
  39
  40 namespace N2
  41 {
  42   struct Swappable
  43   {
  44     Swappable() = default;
  45     Swappable(Swappable&&) = delete;
  46     friend void swap(Swappable&, Swappable&) { }
  47   };
  48 }
  49 static_assert( std::swappable_with<N2::Swappable&, N2::Swappable&> );
  50
  51 namespace N3
  52 {
  53   struct A { };
  54   struct Proxy {
  55     Proxy(A&) { }
  56     friend void swap(Proxy, Proxy) { }
  57   };
  58 }
  59
  60 static_assert( std::swappable_with<N3::A&, N3::A&> );
  61 static_assert( std::swappable_with<N3::A&, N3::Proxy> );
  62 static_assert( std::swappable_with<N3::Proxy, N3::A&> );
  63 static_assert( std::swappable_with<N3::Proxy, N3::Proxy> );
  64
  65 struct C { C(int&) { } };
  66 void swap(int&, C&) { } // not symmetrical
  67 static_assert( ! std::swappable_with<int, C> );
  68 static_assert( ! std::swappable_with<C, int> );
  69
  70 struct D { D(int&) { } };
  71 void swap(int&, D&) { }
  72 void swap(D&&, int&) { } // only accepts rvalues
  73 static_assert( ! std::swappable_with<int&, D> );
  74 static_assert( ! std::swappable_with<D, int> );
  75
  76 struct E { E(int&) { } };
  77 void swap(int, E&&) { } // only accepts rvalues
  78 void swap(E&, int) { }
  79 static_assert( ! std::swappable_with<int, E> );
  80 static_assert( ! std::swappable_with<E, int> );