template<typename T, typename U>
inline constexpr T type_pun(const U & x) {
    static_assert(std::is_trivial<T>::value && std::is_trivial<U>::value, "Cannot use type_pun with non-trivial data" );
    static_assert(sizeof(T) == sizeof(U), "type_pun must be used on identically sized types");
    union in_out {
        U in;
        T out;

        inline constexpr explicit in_out(const U &x) : in(x)
        {
        }

        inline T get() const {
            return const_cast<const T&>(out);
        }
    };
    return in_out(in_out(x)).get();
}