# Get the non-`is_fictive` module on which `self` is based on.
	#
	# On non-fictive module, this returns `self`.
	# On fictive modules, this is used to refer the module which `self` is based on.
	#
	# This attribute should be set when a fictive module is created. See `is_fictive`.
	var first_real_mmodule: MModule = self is writable