anchor.diff:      (let* ((self-varrec (attr-ref attrs 'self)))
         (form-attr-set! form 'self-closure
                         (if (and self-varrec
  -                               (not (varrec-quasi-written? self-varrec)))
  +                               (not (varrec-written? self-varrec)))
                             (resolve-closure-var self-varrec (1+ depth)
                                                  self-closure-cell)
                             false)))
  
positive.code:   (dolist (varrec varrecs)
      (let* ((state (varrec-attr-remove varrec 'state)))
        (cond ((= state 6) (error "bad variable ~S" (car varrec)))
              ((or (= state 2) (= state 3))
               (rplacd (cdr form) (cons (list 'define varrec (quoted-unspecified))
                                        (cddr form)))))
        (varrec-attr-set! varrec 'access
  
negative.code:   (classify-variables program)
    (collect-closures program)
    (introduce-boxes program)
    (decompose-lambdas program false)
    (codegen-program program)
    ;(format~ true "~S~%" (debug-form program))
    )
  