Comment 1 for bug 1904434

Also:

(let ((s (make-bug024 :x 14)))
           (compile nil
                    `(lambda (a)
                       (when (typep a '(member #\8 ,s))
                         (bug024-x a)))))

==>

; in: LAMBDA (A)
; (BUG024-X A)
;
; caught STYLE-WARNING:
; Lisp error during constant folding:
; The function SB-C::%STRUCTURE-IS-A is undefined.
;
; compilation unit finished
; caught 1 STYLE-WARNING condition
#<FUNCTION (LAMBDA (A)) {52DBD37B}>
T
NIL