// Unreference tuple for raw memory copy.
// Primary template for non referenced elements.
template <class T, class = void>
struct tuple_unref {
    tuple_unref(T& t) noexcept : value(t) { }
    T& value;
};

// A specialization for tuple containing
// at least one reference type.
template <class... Ts>
struct tuple_unref<std::tuple<Ts...>,
                   std::enable_if_t<(std::is_reference_v<Ts> || ...)>> {
private:
    using T = std::tuple<std::remove_reference_t<Ts>...>;

    T value_;
    std::tuple<Ts...>& ref_;

public:
    tuple_unref(std::tuple<Ts...>& t) noexcept : ref_(t) { }
    ~tuple_unref() { ref_ = std::move(value_); }

    T& value = value_;
};