redef fun lookup_bound(mmodule, resolved_receiver)
	do
		# There is two possible invalid cases: the vt does not exists in resolved_receiver or the bound is broken
		if not resolved_receiver.has_mproperty(mmodule, mproperty) then return new MErrorType(model)
		return lookup_single_definition(mmodule, resolved_receiver).bound or else new MErrorType(model)
	end

	redef fun lookup_bound(mmodule: MModule, resolved_receiver: MType): MType
	do
		assert not resolved_receiver.need_anchor
		resolved_receiver = resolved_receiver.undecorate
		assert resolved_receiver isa MClassType # It is the only remaining type
		var goalclass = self.mclass
		if resolved_receiver.mclass == goalclass then
			return resolved_receiver.arguments[self.rank]
		end
		var supertypes = resolved_receiver.collect_mtypes(mmodule)
		for t in supertypes do
			if t.mclass == goalclass then
				# Yeah! c specialize goalclass with a "super `t'". So the question is what is the argument of f
				# FIXME: Here, we stop on the first goal. Should we check others and detect inconsistencies?
				var res = t.arguments[self.rank]
				return res
			end
		end
		# Cannot found `self` in `resolved_receiver`
		return new MErrorType(model)
	end