make_pair.cc

template <typename T>
struct __stripper {
    using type = T;
};

template <typename T>
struct ___stripper<std::reference_wrapper<T>> {
    using type = T&;
};

template <typename T1, typename T2>
constexpr auto make_pair(T1 &&x, T2 &&y) -> std::pair<
        typename __stripper<typename std::decay<T1>::type>::type,
        typename __stripper<typename std::decay<T2>::type>::type
> {
    using __pair_type = std::pair<
        typename __stripper<typename std::decay<T1>::type>::type,
        typename __stripper<typename std::decay<T2>::type>::type
    >;
    return __pair_type(
        std::forward<T1>(x),
        std::forward<T2>(y)
    );
}