#include <iostream>

#include <chrono>
#include <cassert>

namespace std { namespace chrono {

template<>
template<>
#ifdef __clang__
duration<unsigned, std::milli>::duration(const std::chrono::duration<signed, std::milli>& d, void*)
#else
duration<unsigned, std::milli>::duration(const std::chrono::duration<signed, std::milli>& d)
#endif
{
    assert(!"WOW");
}

}}

void foo(std::chrono::duration<unsigned, std::milli> m)
{
    std::cout << m.count() << std::endl;
}

int main(int argc, char* argv[])
{
    using namespace std::chrono;
    foo(std::chrono::duration<signed, std::milli>(-42));
    return 0;
}