anchor.diff:  (defmethod initialize-instance ((instance standard-object) &rest initargs)
     (apply #'shared-initialize instance t initargs))
   
  +(sys.int::defglobal *reinitialize-instance-initargs-cache* (make-hash-table))
  +
   (defun check-reinitialize-instance-initargs (object initargs)
     (check-initargs
  -   (class-of object)
  +   (class-of object) *reinitialize-instance-initargs-cache*
      (list (list #'reinitialize-instance object)
            (list #'shared-initialize object t))
      initargs
  
positive.code:            ((instance standard-object) (new-class symbol) &rest initargs)
    (apply #'change-class instance (find-class new-class) initargs))
  
  (defun check-update-instance-for-different-class-initargs (old new initargs)
    (check-initargs
     (class-of new)
     (list (list #'update-instance-for-different-class old new)
           (list #'shared-initialize new t))
     initargs
  
negative.code:   ;; Refinalize any subclasses.
    (dolist (subclass (safe-class-direct-subclasses class))
      (std-after-reinitialization-for-classes subclass))
    ;; Flush the initarg caches for this class.
    (flush-initarg-caches class)
    ;; Update dependents
    (safe-map-dependents class (lambda (dep)
                                 (apply #'update-dependent class dep args))))
  