is it a bug? protection attributes on interfaces/abstracts have no effect outside module?

[Daniel Murphy]

C.blub4 - yes, it looks like a bug

A.blub3 - I've seen a bug about this somewhere in bugzilla, and it's 
debatable whether it's a bug or not.  Private functions are not virtual, so 
it doesn't override anything, it just uses the same name as an interface 
method.  Allowing override here is probably a bug.