# Collect all classes refined in `self`
	fun collect_redef_mclasses(filter: nullable ModelFilter): Set[MClass] do
		var mclasses = new HashSet[MClass]
		for mclassdef in mclassdefs do
			if filter != null and not filter.accept_mentity(mclassdef.mclass) then continue
			if not mclassdef.is_intro then mclasses.add(mclassdef.mclass)
		end
		return mclasses
	end