+ ;; FIXME: perhaps this should share a format-string
+ ;; with INVALID-ARRAY-INDEX-ERROR or
+ ;; INDEX-TOO-LARGE-ERROR?
+ (error 'simple-type-error
+ :format-control "invalid index ~W in ~S"
+ :format-arguments (list index array)
+ :datum index
+ :expected-type `(integer 0 (,length)))