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//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
// <tuple>
// template <class... Types> class tuple;
// template <class... Types>
// void swap(const tuple<Types...>& x, const tuple<Types...>& y);
// UNSUPPORTED: c++03, c++11, c++14, c++17, c++20
#include <tuple>
#include <cassert>
struct S {
int* calls;
friend constexpr void swap(S& a, S& b) {
*a.calls += 1;
*b.calls += 1;
}
};
struct CS {
int* calls;
friend constexpr void swap(const CS& a, const CS& b) {
*a.calls += 1;
*b.calls += 1;
}
};
static_assert(std::is_swappable_v<std::tuple<>>);
static_assert(std::is_swappable_v<std::tuple<S>>);
static_assert(std::is_swappable_v<std::tuple<CS>>);
static_assert(std::is_swappable_v<std::tuple<S&>>);
static_assert(std::is_swappable_v<std::tuple<CS, S>>);
static_assert(std::is_swappable_v<std::tuple<CS, S&>>);
static_assert(std::is_swappable_v<const std::tuple<>>);
static_assert(!std::is_swappable_v<const std::tuple<S>>);
static_assert(std::is_swappable_v<const std::tuple<CS>>);
static_assert(std::is_swappable_v<const std::tuple<S&>>);
static_assert(!std::is_swappable_v<const std::tuple<CS, S>>);
static_assert(std::is_swappable_v<const std::tuple<CS, S&>>);
constexpr bool test() {
int cs_calls = 0;
int s_calls = 0;
S s1{&s_calls};
S s2{&s_calls};
const std::tuple<CS, S&> t1 = {CS{&cs_calls}, s1};
const std::tuple<CS, S&> t2 = {CS{&cs_calls}, s2};
swap(t1, t2);
assert(cs_calls == 2);
assert(s_calls == 2);
return true;
}
int main(int, char**) {
test();
static_assert(test());
return 0;
}
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