(defmethod transform ((xform (eql 'shadow-values)) (elm identifier))
  (if (and *shadowed-arguments-name*
           (equal (identifier-name elm) *arguments-name*))
    (make-identifier :name *shadowed-arguments-name*
                     :start (source-element-start elm)
                     :end (source-element-end elm))
    (call-next-method)))