Similar example. 1 commenter tries it with VB and compiler will not allow you to change opt ional parameter values between overrides, another commenter tries it with c and gets the same behaviour as the c# 4.0 implementation.

At least you know the lineage of the implementation (although it still sucks).

@Daniel: There is no need for that approach, when you define something as virtual and then override it in a descendent class, you effectively replace the method in the parent class. If this behaviour was continued for methods with optional parameters then f1.Foo(); should invoke Foo(2).

Off to see if I can find any reasoning behind this…