Re: Templates and derivation

template<typename T> class MF : public T
{
   public:
     typedef T ImplType;
};

template<typename U> struct Holder
{
   Holder() : m_pU( NULL ) {}

   ~Holder()
   {
     if ( m_pU )
     {
       delete m_pU; m_pU = NULL;
     }
   }

   U* m_pU;
};

int main( int, char*[] )
{
   MF<Derived>* pMFD = new MF<Derived>;

   Holder<MF<Base> > baseHolder;
   baseHolder.m_pU = pMFD; // <-- compile error: MF<Derived>* not convertible to
                           // MF<Base>*

   return 0;
}