# Collect all virtual types inherited by `self`
	fun collect_inherited_vts(mainmodule: MModule, filter: nullable ModelFilter): Set[MVirtualTypeProp] do
		var res = new HashSet[MVirtualTypeProp]
		for mproperty in collect_inherited_mproperties(mainmodule, filter) do
			if mproperty isa MVirtualTypeProp then res.add(mproperty)
		end
		return res
	end