llvm/libcxx/test/std/utilities/expected/expected.unexpected/assign/assign.move.pass.cpp

//===----------------------------------------------------------------------===//
//
// 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 unexpected& operator=(unexpected&&) = default;

#include <cassert>
#include <expected>
#include <utility>

struct Error {
  int i;
  constexpr Error(int ii) : i(ii) {}
  constexpr Error& operator=(Error&& other) {
    i       = other.i;
    other.i = 0;
    return *this;
  }
};

constexpr bool test() {
  std::unexpected<Error> unex1(4);
  std::unexpected<Error> unex2(5);
  unex1 = std::move(unex2);
  assert(unex1.error().i == 5);
  assert(unex2.error().i == 0);
  return true;
}

int main(int, char**) {
  test();
  static_assert(test());
  return 0;
}