why you can't overload operator.

class Y
{
public:
    void f();
    // ...
};

class X
{   // assume that you can overload .
    Y* p;
    Y& operator.() { return *p; }
    void f();
    // ...
};

void g(X& x)
{
    x.f();  // X::f or Y::f or error?
}