Yes when I looked at RB (in 99) I guess that they also used existing instances to try to get more information but mainly for instance variables.
I am not aware of such code. RBRefactoryTyper is part of the refactoring engine since I first looked at it around ESUG 2002. It is relatively hidden, and only used by a few refactorings to provide better default suggestions (i.e. extract to component). It is also used in OB to provide a better default class comment template. And in ECompletion for better suggestions since RoelTyper is not useable anymore.
I would really like to see more work around practical tools that can help us. I have the work on type inference from francisco garau on my hard-disc. But this is a pity that nobody build on top of that.
Never heard of that code. Lukas -- Lukas Renggli www.lukas-renggli.ch