anchor.diff:  
   (defun expex-funinfo-env-add ()
     (let s (expex-sym)
  -    (aif *expex-funinfo*
  -         (funinfo-env-add ! s)
  -	     (error "expression-expander: FUNINFO missing. Cannot make GENSYM"))
  +    (!? *expex-funinfo*
  +        (funinfo-env-add ! s)
  +	    (error "expression-expander: FUNINFO missing. Cannot make GENSYM"))
   	s))
   
   (defun expex-internal-symbol? (x)
  
positive.code: 	(cons p a)))
  
  (defun expex-move-arg-vm-scope (ex x)
    (aif (%%vm-scope-body x)
         (let s (expex-funinfo-env-add)
           (cons (expex-body ex ! s) s))
  	   (cons nil nil)))
  
  (defun lambda-expression-needing-cps? (x)
    (and (lambda-expr? x)
         (funinfo-needs-cps? (get-lambda-funinfo x))))
  
  (defun expex-move-arg-std (ex x)
    (with (s (expex-funinfo-env-add)
      	 (moved new-expr) (expex-expr ex x))
        (when (lambda-expression-needing-cps? x)
          (transpiler-add-cps-function *current-transpiler* s))
        (cons (append moved
  		    		(? (expex-returnable? ex new-expr.)
  
negative.code: (defun expex-cps (x)
    (and (or (%setq? x)
              (%set-atom-fun? x))
         (lambda-expression-needs-cps? (%setq-value x))
         (transpiler-add-cps-function *current-transpiler* (%setq-place x))))
  
  (defun expex-vm-go-nil (ex x)
  