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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
//
//===----------------------------------------------------------------------===//
// UNSUPPORTED: c++03, c++11, c++14, c++17, c++20
// constexpr void swap(unexpected& other) noexcept(is_nothrow_swappable_v<E>);
//
// Mandates: is_swappable_v<E> is true.
//
// Effects: Equivalent to: using std::swap; swap(unex, other.unex);
#include <cassert>
#include <concepts>
#include <expected>
#include <utility>
// test noexcept
struct NoexceptSwap {
friend void swap(NoexceptSwap&, NoexceptSwap&) noexcept;
};
struct MayThrowSwap {
friend void swap(MayThrowSwap&, MayThrowSwap&);
};
template <class T>
concept MemberSwapNoexcept =
requires(T& t1, T& t2) {
{ t1.swap(t2) } noexcept;
};
static_assert(MemberSwapNoexcept<std::unexpected<NoexceptSwap>>);
static_assert(!MemberSwapNoexcept<std::unexpected<MayThrowSwap>>);
struct ADLSwap {
constexpr ADLSwap(int ii) : i(ii) {}
ADLSwap& operator=(const ADLSwap&) = delete;
int i;
constexpr friend void swap(ADLSwap& x, ADLSwap& y) { std::swap(x.i, y.i); }
};
constexpr bool test() {
// using std::swap;
{
std::unexpected<int> unex1(5);
std::unexpected<int> unex2(6);
unex1.swap(unex2);
assert(unex1.error() == 6);
assert(unex2.error() == 5);
}
// adl swap
{
std::unexpected<ADLSwap> unex1(5);
std::unexpected<ADLSwap> unex2(6);
unex1.swap(unex2);
assert(unex1.error().i == 6);
assert(unex2.error().i == 5);
}
return true;
}
int main(int, char**) {
test();
static_assert(test());
return 0;
}
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