remove_reference_wrapper.cpp

// this should never be able to be instantiated
template<typename T>
struct _remove_reference_wrapper;

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

template<typename T, typename = void>
struct remove_reference_wrapper {
    using type = T;
};

template<typename T>
struct remove_reference_wrapper<T, std::enable_if_t<is_template_for_v<std::reference_wrapper, T>>> :
    public _remove_reference_wrapper<std::decay_t<T>>
{};

template<typename T>
using remove_reference_wrapper_t = typename remove_reference_wrapper<T>::type;