bug in pcl::slot-exists-p

[alarson@src.honeywell.com (Aaron Larson)]

pcl-system-date     = "3/17/88  St. Patrick's Day PCL"
lisp implementation = Franz Inc. Extended Common Lisp 2.0 (9/8/87 8:24)

(pcl::slot-exists-p obj 'slot-name) returns true for all slot names.

Probable cause is the following from slots.lisp:

(defun slot-value-using-class--class-internal (class object slot-name
                                                   dont-call-slot-missing-p
						   default)
  (with-slot-internal--class (class object slot-name nil)
    (:instance (index) (get-static-slot--class object index))
    (:dynamic (loc newp) (if (eq newp t) (setf (car loc) default) (car loc)))
    (:class (slotd) (slotd-initform slotd))
    (nil () (unless dont-call-slot-missing-p
	      (slot-missing object slot-name)))))

Should be something like:

    (nil () (if dont-call-slot-missing-p
	      (return-from slot-value-using-class--class-internal default)
	      (slot-missing object slot-name)))))

For some reason just giving the default rather than using a return-from did
not work.  Since I noticed this in a non exported function, I didn't spend
much time tracking down why.  The definition of the function is unchanged
in the latest release as well.