(declare (type function fun))
;; The Lisp-level type FUNCTION can conceal a multitude of sins..
(case (sb-kernel:widetag-of fun)
- ((#.sb-vm:simple-fun-header-widetag #.sb-vm:closure-fun-header-widetag)
+ (#.sb-vm:simple-fun-header-widetag
(sb-kernel:%simple-fun-arglist fun))
(#.sb-vm:closure-header-widetag (get-arglist
(sb-kernel:%closure-fun fun)))