anchor.diff:                                                        ,(cadr slot))
                                                       ,initform))
                   else do
  -                  (log:warn "Undefined slot ~a in ~a" (first slot) name))
  +                  (log:warn "Undefined slot ~a in ~a" (first slot) final-name))
            (:accessor-name-transformer #'class*:name-identity))
  -       (defclass ,name ,(cons temp-name
  -                         (mapcar #'class-name
  -                                 (mopu:direct-superclasses name))) ()))))
  +       (defclass ,final-name ,(cons temp-name
  +                               (mapcar #'class-name
  +                                       (mopu:direct-superclasses final-name))) ()))))
   
   (export-always 'load-system)
   (defun load-system (system)
  
positive.code:   "Helper macro to customize NAME class slots.
  
  Classes can be modes or a core class like `browser', `buffer', `minibuffer',
  `window' prefixed by REPLACEME.
  
  The `%slot-default' variable is replaced by the slot initform.
  
  Example that sets some defaults for all buffers:
  
  \(define-configuration REPLACEME-buffer
    ((status-buffer-height 24)
     (default-modes (append '(vi-normal-mode) %slot-default))))
  
  
negative.code: generated class containing the specialized hostlists and the original
  `blocker-mode'."
  
    (let* ((final-name (intern (str:concat "REPLACEME-" (string name)) (symbol-package name)))
           (temp-name (gentemp (string final-name) (symbol-package name))))
      (dolist (name (list name final-name))
        (unless (find-class name nil)
          (error "define-configuration argument ~a is not a known class." name)))
      `(progn
         (define-class ,temp-name ()
           ,(loop with super-class = (closer-mop:ensure-finalized (find-class final-name))
                  for slot in (first slots)
                  for known-slot? = (find (first slot) (mopu:slot-names super-class))
                  for initform = (and known-slot?
  