anchor.diff:                  args)
         args))
   
  +(defun %canonicalize-definition-class (maybe-explicit-definition-class implicit-definition-class)
  +  (let ((maybe-explicit-definition-class-var (gensym (string '#:maybe-explicit-definition-class))))
  +    `(let ((,maybe-explicit-definition-class-var ,maybe-explicit-definition-class))
  +       (if (eq ,maybe-explicit-definition-class-var t)
  +           ,implicit-definition-class
  +           ,maybe-explicit-definition-class-var))))
  +
   (defmethod defsys:expand ((system defsys:simple-expansion-mixin) name environment args &key)
     (declare (ignore environment))
     (let ((initargs-var (gensym (string '#:initargs))))
  
positive.code:   (:method ((system defsys:system) &rest initargs)
      initargs))
  
  (defun %canonicalize-definition-class (maybe-explicit-definition-class implicit-definition-class)
    (if (eq maybe-explicit-definition-class t)
        implicit-definition-class
        maybe-explicit-definition-class))
  
  (defun %every-other (function)
    (let ((processp t))
      (lambda (key value)
  
negative.code:                `(apply #'defsys:definition-class ,system ',name ,initargs-var)))
            (if (defsys:explicit-definition-class-p system)
                (destructuring-bind (maybe-explicit-definition-class &rest args) args
                  (values (%canonicalize-definition-class maybe-explicit-definition-class
                                                          implicit-definition-class-form)
                          args))
                (values implicit-definition-class-form args)))
        `(let ((,initargs-var (list ,@(%fix-args (apply #'defsys:expand-args system args)))))
  