template<class T>
struct C
{  public:
   T a;    //error C<T>::a' uses undefined class 'A'     with   [   T=A  ]

};

class A:public C<A> 
{     
--SKIP--
};

template<class T>
struct C
{  public:
      void Do(void){T::Do();} //Можно

};

class A:public C<A> 
{     
static void Do(void){...}
};