anchor.diff:  (defmethod reinitialize-instance :before ((class built-in-class) &rest args)
     (error "Cannot reinitialize built-in classes."))
   
  -(defmethod finalize-inheritance ((class built-in-class))
  -  (std-finalize-inheritance class)
  -  (values))
  -(defmethod compute-slots ((class built-in-class))
  -  (std-compute-slots class))
  -(defmethod compute-class-precedence-list ((class built-in-class))
  -  (std-compute-class-precedence-list class))
  -
   ;;; Structure-class.
   
   (defclass structure-class (clos-class)
  
positive.code: (defmethod finalize-inheritance ((class structure-class))
    (std-finalize-inheritance class)
    (values))
  (defmethod compute-slots ((class structure-class))
    (std-compute-slots class))
  (defmethod compute-class-precedence-list ((class structure-class))
    (std-compute-class-precedence-list class))
  
  
negative.code: (defmethod compute-slots ((class std-class))
    (std-compute-slots class))
  
  (defmethod compute-slots :around ((class std-class))
    (let ((effective-slots (call-next-method)))
      (std-compute-slot-layouts class effective-slots)
      effective-slots))
  
  (defgeneric compute-effective-slot-definition (class name direct-slots))
  (defmethod compute-effective-slot-definition ((class std-class) name direct-slots)
    (std-compute-effective-slot-definition class name direct-slots))
  