warning2.c

this is a gcc file, you can download it and learn its usetility, for further detail please look at t

// g++ ought to warn about casting a base pointer to a derived reference.
// Build don't link:

struct A {
  virtual void f () = 0;
};

struct B: public A { void f () { } };

int main()
{
  B* bp;
  A& ar = (A&)bp;		// WARNING - 
}