I'm sure we all knew there had to be a good reason for &aux, but maybe
we had trouble remembering what it might be?
(defstruct (delayed-iseq
(:constructor iseq (start-or-end
&optional (end 0 endp) (by 1) strict-direction? &aux (end? endp))))
"Delayed index sequence evaluation."
start-or-end end end? by strict-direction?)
- n