Incorrect runtime error in compiled code

[Paul F. Dietz]

(defun bug071 (a)
  (declare (optimize (debug 3)))
  (block b8
    (multiple-value-bind (v1)
        (if (common-lisp:handler-case
                (let ((v3 (if a 10 3)))
                  (block b8
                    (truncate
                     (ignore-errors
                      (return-from b8
                        (block b3 (ceiling v3))
                        ))))))
            0 0)
      0)))

(bug071 nil) ==>

Value of SB-C::VAL in
(TRUNCATE (IGNORE-ERRORS (RETURN-FROM B8 (BLOCK B3 (CEILING V3)))) 1)

is
  NIL,
not a
  REAL.
   [Condition of type SIMPLE-TYPE-ERROR]
[...]
  0: (SB-C::%COMPILE-TIME-TYPE-ERROR (NIL) REAL #<unused argument> (SB-C::VAL) "(TRUNCATE (IGNORE-ERRORS (RETURN-FROM B8 (BLOCK B3 (CEILING V3)))) 1)" NIL)
  1: (BUG071 #<unused argument>)
 [...]