anchor.diff:       (not (funinfo-used-var? fi x))
        (+! (funinfo-used-vars fi) (list x))))
   
  -(defun funinfo-get-name (fi)
  -  (| (funinfo-name fi)
  -     (funinfo-get-name (funinfo-parent fi))))
  +
  +;;;; IMMUTABLES
   
   (defun funinfo-immutable? (fi x)
     (member x (funinfo-immutables fi) :test #'eq))
  
positive.code: ;;;;; tré – Copyright (c) 2006–2007,2009–2013 Sven Michael Klose <pixel@copei.de>
  
  ;;;; ARGUMENTS
  
  
negative.code:   (| (funinfo-arg? fi x)
       (funinfo-var? fi x)))
  
  (defun funinfo-var-or-lexical? (fi x)
    (!? (funinfo-parent fi)
        (| (funinfo-arg-or-var? fi x)
           (funinfo-var-or-lexical? ! x))))
  
  
  ;;;; ENVIRONMENT
  
  (defun funinfo-parent-var? (fi x)
    (!? (funinfo-parent fi)
        (| (funinfo-arg-or-var? ! x)
           (funinfo-parent-var? ! x))))
  
  (defun funinfo-var-pos (fi x)
    (& (funinfo-parent fi)
       (position x (funinfo-vars fi) :test #'eq)))
  
  (defun funinfosym-var-pos (fi-sym x)
    (funinfo-var-pos (get-funinfo-by-sym fi-sym) x))
  
  (defun funinfo-var-add (fi x)
    (unless (atom x)
  