((and (csubtypep type (specifier-type 'sequence))
(find-class output-type-spec nil))
(let ((class (find-class output-type-spec)))
+ (unless (sb!mop:class-finalized-p class)
+ (sb!mop:finalize-inheritance class))
(sb!sequence:make-sequence-like
(sb!mop:class-prototype class)
(length object) :initial-contents object)))