Overloading/Inheritance issue

[Steve Schveighoffer]

Hi,

I am wondering if the following behavior is intentional and if so, why.  Given the code below:

class X
{
  public int foo()
  {
    return foo(0);
  }

  public int foo(int y)
  {
    return 2;
  }
}

class Y : X
{
  public int foo(int y)
  {
    return 3;
  }
}

int main(char [][] argv)
{
  Y y = new Y;
  y.foo(); //does not compile, says that the argument type doesn't match
  y.foo(1);
  X x = y;
  x.foo();
  return 0;
}


How come the marked line above does not compile?  Clearly there is no ambiguity that I want to call the base's foo, which in turn should call Y's foo(int) with an argument of 0.  It's not that the method is not accessible, because I can clearly access it by casting to an X type (as I have done in the subsequent lines).

If you interpret the code, I'm defining a default behavior for foo() with no arguments.  A derived class which wants to keep the default behavior of foo() as calling foo(0), should only need to override foo(int).  However, the compiler does not allow this.  Why?  Is there a workaround (besides implementing a stub function which calls super.foo())?  Maybe there is a different method of defining in a base class one version of a function in terms of another?

-Steve