test/std/time/time.cal/time.cal.day/time.cal.day.members/decrement.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

// <chrono>
// class day;

//  constexpr day& operator--() noexcept;
//  constexpr day operator--(int) noexcept;

#include <chrono>
#include <type_traits>
#include <cassert>

#include "test_macros.h"

using day = std::chrono::day;

constexpr bool test() {
  for (unsigned i = 10; i <= 20; ++i) {
    day d(i);
    assert(static_cast<unsigned>(--d) == i - 1);
    assert(static_cast<unsigned>(d--) == i - 1);
    assert(static_cast<unsigned>(d) == i - 2);
  }
  return true;
}

int main(int, char**) {
  ASSERT_NOEXCEPT(--(std::declval<day&>()));
  ASSERT_NOEXCEPT((std::declval<day&>())--);

  ASSERT_SAME_TYPE(day, decltype(std::declval<day&>()--));
  ASSERT_SAME_TYPE(day&, decltype(--std::declval<day&>()));

  test();
  static_assert(test());

  return 0;
}