I want to support in fuel 1.8 some way of specifying that a class has
been renamed. Something like:

FLMaterializer newDefault
� � classRenames: { #OldClass -> #NewClass }
� � materializeFrom: aFile.

Would this solve your problem?

Yes it would, but the real issue for me is whether or not the migration code stays forever in the code base, or should a one time migration step be run (and keep no migration trail in the Fuel code).