final/test/utilities/time/time.duration/time.duration.arithmetic/op_-.pass.cpp

//===----------------------------------------------------------------------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is dual licensed under the MIT and the University of Illinois Open
// Source Licenses. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//

// <chrono>

// duration

// duration operator-() const;

#include <chrono>
#include <cassert>

int main()
{
    {
    const std::chrono::minutes m(3);
    std::chrono::minutes m2 = -m;
    assert(m2.count() == -m.count());
    }
#ifndef _LIBCPP_HAS_NO_CONSTEXPR
    {
    constexpr std::chrono::minutes m(3);
    constexpr std::chrono::minutes m2 = -m;
    static_assert(m2.count() == -m.count(), "");
    }
#endif
}