Making a template parameter a friend?

Question

Example:

template
class Base {
public:
    Base();
    friend class T;
};

Now this doesn\'t work... Is there a way of doing

Answer 1

I found a simple trick to declare template parameters as friends:

template < typename T>
struct type_wrapper 
{ 
   typedef T type; 
}; 


template < typename T> class foo 
{ 
  friend class type_wrapper < T>::type 
};   // type_wrapper< T>::type == T

However I do not know how this could help to define an alternative version of a class sealer.