doru I wonder why there is a FAMIXMethod>>initialize initialize super initialize. parentClass := FMOneSlot new owner: self; oppInstVar: #methods; yourself. and why there is the following definition in FamixType initialize super initialize. subInheritances := FMManySlot new owner: self; oppInstVar: #superclass; yourself. methods := FMManySlot new owner: self; oppInstVar: #parentClass; yourself. container := FMOneSlot new owner: self; oppInstVar: #types; yourself. superInheritances := FMManySlot new owner: self; oppInstVar: #subclass; yourself. attributes := FMManySlot new owner: self; oppInstVar: #parentClass; yourself. do we have to do it because we do not specify in the Slot the type of the target oppInstVar class? Stef