anchor.diff:  
   (defmethod add-function-ignore (environment function-name ignore)
     (make-instance 'function-ignore
  +    :next environment
       :name function-name
       :ignore ignore))
   
  
positive.code: 
  (defmethod add-local-function (environment function-name)
    (make-instance 'function
      :name function-name
      :identity (gensym)))
  
  
negative.code: 
  (defmethod add-variable-dynamic-extent (environment symbol)
    (make-instance 'variable-dynamic-extent
      :next environment
      :name symbol))
  
  (defclass function-dynamic-extent (entry)
  