Oh, I see, the problem is that the functions in the mixin would call the hidden functions instead of the new ones.
I have also found the workaround:
class DefaultTalkyDuck: Duck{
mixin DuckImpl;
}
class TalkyDuck: DefaultTalkyDuck{
override void quack(){writeln("quack! quack!");}
}
Sorry for the noise.
-Timon
