anchor.diff:              new-value (class-of object) object slot-name))))
   
   (defun std-slot-boundp (instance slot-name)
  +  (when (not (symbolp slot-name))
  +    (setf slot-name (slot-definition-name slot-name)))
     (let ((location (slot-location (class-of instance) slot-name))
           (slots (std-instance-slots instance)))
       (not (eq secret-unbound-value (slot-contents slots location)))))
   (defun fc-std-slot-boundp (instance slot-name)
  +  (when (not (symbolp slot-name))
  +    (setf slot-name (slot-definition-name slot-name)))
     (let ((location (slot-location (class-of instance) slot-name))
           (slots (funcallable-std-instance-slots instance)))
       (not (eq secret-unbound-value (slot-contents slots location)))))
  
positive.code:   (std-slot-exists-p instance slot-name))
  (defmethod slot-exists-p-using-class
             ((class funcallable-standard-class) instance slot-name)
    (std-slot-exists-p instance slot-name))
  
  (defgeneric slot-boundp-using-class (class instance slot-name))
  (defmethod slot-boundp-using-class
  
negative.code:   (std-slot-boundp instance slot-name))
  (defmethod slot-boundp-using-class
             ((class funcallable-standard-class) instance slot-name)
    (fc-std-slot-boundp instance slot-name))
  
  (defgeneric slot-makunbound-using-class (class instance slot-name))
  (defmethod slot-makunbound-using-class
  