anchor.diff:  
   
   (defmacro assert-not-finalized (instance &optional format-control
  -					 &rest format-args)
  +				&rest format-args)
     (with-gensyms (%instance)
  -    `(let (,%instance ,instance)
  +    `(let ((,%instance ,instance))
          (when (instance-finalized-p ,%instance)
   	 ,@(cond
   	     (format-control
  -	      `(error 'simple-instance-finalized-error
  -		      :instance ,%instance
  -		      :format-control ,format-control
  -		      :format-arguments (list ,@format-args)))
  +	      `((error 'simple-instance-finalized-error
  +		       :instance ,%instance
  +		       :format-control ,format-control
  +		       :format-arguments (list ,@format-args))))
   	     (t
  -	      `(error 'instance-finalized-error
  -		      :instance ,%instance)))))))
  +	      `((error 'instance-finalized-error
  +		       :instance ,%instance))))))))
   
   
   ;;; * FINALIZABLE-INSTANCE
  
positive.code: 
  (defmethod instance-finalized-p ((instance finalizable-instance))
    (%instance-finalized-p instance))
  
  (defmethod finalize :around ((instance finalizable-instance))
    (unless (instance-finalized-p instance)
  
negative.code: 
  
  (defgeneric instance-finalized-p (instance))
  
  (defgeneric (setf instance-finalized-p) (new-value instance))
  
  
  ;;; * Condition Protocol: INSTANCE-FINALIZED
  