anchor.diff:                 (accept-action
                   (pop stack)
                   (return (pop stack)))
  -               (error-action
  +               (null
                   (error (make-condition
                           'yacc-parse-error
                           :terminal (if (eq symbol 'yacc-eof-symbol) nil symbol)
  
positive.code:         (goto-array (parser-goto parser)))
      (flet ((action (i a)
               (declare (type index i) (symbol a))
               (or (cdr (assoc a (aref action-array i)))
                   (make-error-action)))
             (goto (i a)
               (declare (type index i) (symbol a))
               (or (cdr (assoc a (aref goto-array i)))
  
negative.code:                (let ((id (kernel-id k)))
                   (dolist (s symbols)
                     (declare (symbol s))
                     (let ((s-a (assoc s (aref action id))))
                       (cond
                         ((cdr s-a)
                          (multiple-value-bind (new-action s-r r-r)
                              (handle-conflict
                               (cdr s-a) a grammar action-productions
                               id s muffle-conflicts)
                            (setf (cdr s-a) new-action)
                            (incf sr-conflicts s-r) (incf rr-conflicts r-r)))
                         (s-a
                          (setf (cdr s-a) a))
                         (t (push (cons s a) (aref action id))))))))
               (set-goto (k symbols target)
                 (let ((i (kernel-id k)) (j (kernel-id target)))
                   (dolist (s symbols)
  