# Set the visibility of an imported module
	# REQUIRE: the visibility of the modules imported by `m` are already set for `m`
	fun set_visibility_for(m: MModule, v: MVisibility)
	do
		if v == intrude_visibility then
			self.intrude_mmodules.add(m)
			self.intrude_mmodules.add_all(m.intrude_mmodules)
			self.public_mmodules.add_all(m.public_mmodules)
			self.private_mmodules.add_all(m.private_mmodules)
		else if v == public_visibility then
			self.public_mmodules.add(m)
			self.public_mmodules.add_all(m.intrude_mmodules)
			self.public_mmodules.add_all(m.public_mmodules)
		else if v == private_visibility then
			self.private_mmodules.add(m)
			self.private_mmodules.add_all(m.intrude_mmodules)
			self.private_mmodules.add_all(m.public_mmodules)
		else
			print "{self} visibility for {m} = {v}"
			abort # invalid visibility
		end
	end