index_template_parameter_pack.hpp

template <typename T, typename U=void, typename... Types>
constexpr size_t index() {
    return std::is_same<T, U>::value ? 0 : 1 + index<T, Types...>();
}

template<size_t index, typename... T>
struct TypeAtIndex
{
	using type = typename std::tuple_element<index, std::tuple<T...>>::type;
};

template <typename... T>
struct TestPackIndex {
	static constexpr auto value = index<bool ,T...>();
	using type = typename TypeAtIndex<value, T...>::type;
};