Using declaration for type alias template in derived class with tempate base

问题

If the base class depends on the template parameter, its scope is not examined in the unqualified name lookup. I can use the using declaration to introduce names from the base class. Suppose now I have a type alias template in the base class. Can the using declaration be used to introduce it into the derived class?

template<class T>
struct Base
{
    using Type1 = int;

    template<typename S>
    using Type2 = S;
};

template<class T>
struct Derived : Base<T>
{
    using typename Base<T>::Type1;           // Fine
    //using Type1 = typename Base<T>::Type1; // Also fine

    template<typename S>
    using Type2 = typename Base<T>::template Type2<S>;
};

Can the line for Type2 be replaced with something similar to the (uncommented) line for Type1?

来源：https://stackoverflow.com/questions/42445594/using-declaration-for-type-alias-template-in-derived-class-with-tempate-base