libstdc++-v3/testsuite/20_util/optional/swap/2.cc

   1 // { dg-do compile { target c++17 }  }
   2
   3 // Copyright (C) 2016-2021 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 <optional>
  21
  22 // Swappable.
  23 struct A { };
  24
  25 static_assert( std::is_nothrow_swappable_v<A> );
  26 static_assert( std::is_nothrow_swappable_v<std::optional<A>> );
  27
  28 // Swappable, but might throw.
  29 struct B { };
  30 void swap(B&, B&) noexcept(false);
  31
  32 static_assert( std::is_swappable_v<std::optional<B>> );
  33 static_assert( !std::is_nothrow_swappable_v<std::optional<B>> );
  34
  35 // Not swappable, and optional<C> not swappable via the generic std::swap.
  36 struct C { };
  37 void swap(C&, C&) = delete;
  38
  39 static_assert( !std::is_swappable_v<std::optional<C>> );
  40
  41 // Not swappable, and optional<D> not swappable via the generic std::swap.
  42 struct D { D(D&&) = delete; };
  43
  44 static_assert( !std::is_swappable_v<std::optional<D>> );