(:variant ,offset))
,@(when writable
`((defknown ((setf ,fn)) (,lisp-type) ,lisp-type
(:variant ,offset))
,@(when writable
`((defknown ((setf ,fn)) (,lisp-type) ,lisp-type
(define-vop (,set ,set-vop)
(:translate (setf ,fn))
(:variant ,offset)))))))))
(define-vop (,set ,set-vop)
(:translate (setf ,fn))
(:variant ,offset)))))))))