That's the Maybe type. The Maybe monad is this:

  instance Monad Maybe where
    return = Just
    Nothing >>= _ = Nothing
    Just x >>= f = f x

(And is not really related to the discussion)

Right! that definition was the type, thanks for the correction :) still, the Maybe monad is used for computations that may fail, which is often the purpose of the null pointer.

Well, that just pushes the goalposts of the complaint: now Haskell has Int, and those other languages do not.

I meant that in some way one could think of, for instance, C's int as a sum type of just integer and null :) in practice the obvious difference is that a language like Haskell enforce considering both options with its type checker.

No, you can't think of C's int that way - it doesn't have a null.

You are completely right, not sure where my head was :P