I want to partially specialize a class for a class nested inside a template class, like this

template <typename T, typename U = void>
struct base {
  void print() {
    std::cout << "base specialization" << std::endl;
  }
};

template <typename A, typename B>
struct Outer {
  struct Inner {
    A a;
    B b;
  };
};

// What I am trying to achieve
template< params... >
struct base < specialization ... > {
  void print() {
    std::cout << "Outer::Inner specialization" << std::endl;
  }
};

such that its true for all A, B combination of typenames

I would like to achieve

base<Outer<int::char>::Inner>().print();
base<Outer<char::char>::Inner>().print();
base<Outer<int::float>::Inner>().print();

print Outer::Inner specialization