anchor.diff:  			 (funinfo-args fi)))
   
   (defun funinfo-in-env? (fi x)
  -  (href (funinfo-env-hash fi) x))
  +  (? (funinfo-parent fi)
  +     (member x (funinfo-env fi) :test #'eq)
  +     (href (funinfo-env-hash fi) x)))
   
   (defun funinfo-in-args-or-env? (fi x)
     (or (funinfo-arg? fi x)
  
positive.code: 	(error "atom expected"))
    (unless (funinfo-in-env? fi x)
  	; XXX (error "double definition of ~A in ~A" x (funinfo-env fi))
    	(setf (href (funinfo-env-hash fi) x) t)
      (push x (funinfo-env fi)))
    x)
  
  
negative.code: 
  (defun funinfo-env-reset (fi)
    (setf (funinfo-env fi) nil)
    (unless (funinfo-parent fi)
      (setf (funinfo-env-hash fi) (make-hash-table :test #'eq))))
  
  (defun funinfo-add-used-env (fi x)
    (adjoin! x (funinfo-used-env fi) :test #'eq))
  