gcc/libstdc++-v3/testsuite/20_util/tuple/swap_cxx17.cc

// { dg-options "-std=gnu++17" }
// { dg-do compile }

// Copyright (C) 2016-2017 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library.  This library is free
// software; you can redistribute it and/or modify it under the
// terms of the GNU General Public License as published by the
// Free Software Foundation; either version 3, or (at your option)
// any later version.

// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License along
// with this library; see the file COPYING3.  If not see
// <http://www.gnu.org/licenses/>.


// NOTE: This makes use of the fact that we know how moveable
// is implemented on tuple.  If the implementation changed
// this test may begin to fail.

#include <tuple>

// Not swappable, and tuple not swappable via the generic std::swap.
struct C { };
void swap(C&, C&) = delete;

static_assert( !std::is_swappable_v<std::tuple<int, C>> );
static_assert( !std::is_swappable_v<std::tuple<C, int>> );
static_assert( !std::is_swappable_v<std::tuple<int, int, C>> );
static_assert( !std::is_swappable_v<std::tuple<C, int, int>> );

// Not swappable, and tuple not swappable via the generic std::swap.
struct D { D(D&&) = delete; };

static_assert( !std::is_swappable_v<std::tuple<int, D>> );
static_assert( !std::is_swappable_v<std::tuple<D, int>> );
static_assert( !std::is_swappable_v<std::tuple<int, int, D>> );
static_assert( !std::is_swappable_v<std::tuple<D, int, int>> );