Of late, I've been doing a lot of class hierarchy refactoring (in Java). I think that "up calls", methods that call a method in a superclass, are bad news. Calling the super implementation of a method or constructor is not so bad (being the Java equivalent of a Beta inner invocation). At least, it is no worse than having implementation-inheritance in the first place. But I have observed that if a class calls any other method from a superclass, then the code is usually messed up: hierarchy inversion, is-a/has-a confusion, too many responsibilities, or some other sin. Thus, the presence of an up-call is a code smell which should make one step back and think about refactoring.
Disclaimer: I'm talking about API here, not SPI...
