# Collect all mproperties introduced in 'self' with `visibility >= min_visibility`.
	fun collect_intro_mproperties(filter: ModelFilter): Set[MProperty] do
		var set = new HashSet[MProperty]
			for mprop in self.intro_mproperties do
				if not filter.accept_mentity(mprop) then continue
				set.add(mprop)
			end
		return set
	end