anchor.diff:  
   (defun std-after-initialization-for-classes
          (class &key direct-superclasses direct-slots direct-default-initargs &allow-other-keys)
  +  (when (endp direct-superclasses)
  +    (setf direct-superclasses (default-direct-superclasses (class-of class))))
     (dolist (superclass direct-superclasses)
       ;; Open code standard VALIDATE-SUPERCLASS here.
       (when (not (or (and (standardish-class-p (class-of class))
  
positive.code:                `(,key ,value)))))
  
  (defun ensure-class (name &rest all-keys
                            &key
                              (metaclass *the-class-standard-class*)
                              direct-superclasses
                              direct-default-initargs
                            &allow-other-keys)
    (when (symbolp metaclass)
      (setf metaclass (find-class metaclass)))
    (let ((existing (find-class name nil)))
      (cond ((and (not existing)
                  (standardish-class-p metaclass))
             ;; Non-MOP path. Used when creating a new standard (funcallable) class.
             ;; Avoids generic function dispatch.
             (let ((class (apply #'make-instance-clos-class
                                 metaclass
                                 :name name
                                 (compute-class-initialization-arguments all-keys))))
               (setf (find-class name) class)
               class))
            (t
             ;; MOP path.
             (apply #'ensure-class-using-class
                    existing
                    name
                    all-keys)))))
  
  ;;; make-instance-standard-class creates and initializes an instance of
  ;;; standard-class without falling into method lookup.  However, it cannot be
  
negative.code:   (or (eql metaclass *the-class-standard-class*)
        (eql metaclass *the-class-funcallable-standard-class*)))
  
  (defun convert-to-direct-slot-definition (class canonicalized-slot)
    (apply #'make-instance
           (apply #'direct-slot-definition-class
  