template <typename T>

class base

{

public:

   void f() {}

};



class class_a : public base<class_a> {};


class class_b : public base<class_b>, 
                public class_a 
{ 
   using base<class_b>::f; 
};




int main()

{

   class_b b;

   b.f();

   return 0;

}

In function 'int main()':
Line 9: error: 'void base<T>::f() [with T = class_b]' is inaccessible
compilation terminated due to -Wfatal-errors.