`(((typep ,emf 'fixnum)
(let ((.new-value. ,(car required-args+rest-arg))
(.slots. (get-slots-or-nil
- ,(car required-args+rest-arg))))
+ ,(cadr required-args+rest-arg))))
(when .slots.
(setf (clos-slots-ref .slots. ,emf) .new-value.))))))
;; (In cmucl-2.4.8 there was a commented-out third ,@(WHEN