# Collect all mproperties redefined in 'self' with `visibility >= min_visibility`.
	fun collect_redef_mproperties(filter: ModelFilter): Set[MProperty] do
		var set = new HashSet[MProperty]
		for mpropdef in self.mpropdefs do
			if not filter.accept_mentity(mpropdef) then continue
			if mpropdef.mproperty.intro_mclassdef.mclass == self then continue
				set.add(mpropdef.mproperty)
			end
		return set
	end