Plaster

(defmethod c2mop:effective-slot-definition-class ((class stored-class-meta-super) &rest initargs) (destructuring-bind (&key allocation-class &allow-other-keys) initargs (if (every #'stored-class-slot-p (c2mop:class-direct-slots allocation-class)) (find-class 'stored-class-slot-effective) (call-next-method))))