decrement.pass.cpp
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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
// <chrono>
// class day;
// constexpr day& operator--() noexcept;
// constexpr day operator--(int) noexcept;
#include <chrono>
#include <type_traits>
#include <cassert>
#include "test_macros.h"
template <typename D>
constexpr bool testConstexpr()
{
D d1{10};
if (static_cast<unsigned>(--d1) != 9) return false;
if (static_cast<unsigned>(d1--) != 9) return false;
if (static_cast<unsigned>(d1) != 8) return false;
return true;
}
int main(int, char**)
{
using day = std::chrono::day;
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&>() ));
static_assert(testConstexpr<day>(), "");
for (unsigned i = 10; i <= 20; ++i)
{
day day(i);
assert(static_cast<unsigned>(--day) == i - 1);
assert(static_cast<unsigned>(day--) == i - 1);
assert(static_cast<unsigned>(day) == i - 2);
}
return 0;
}