Comment 1 for bug 1739652

Reduced to:

(defun f57 ()
  (declare (optimize (debug 1)))
  (let ((v (list (list :good)
                 (labels ((r (x)
                            (cond (x)
                                  (t
                                   (r 33)))))
                   (r nil)))))
    (declare (dynamic-extent v))
    (caar v)))