anchor.diff:             (in? x. '%stack '%vec '%set-vec
   				   'vm-go 'vm-go-nil
   				   '%transpiler-native '%transpiler-string
  -				   '%var
  +				   '%var '%quote
   				   '%no-expex))))
   
   ;; Check if an expression has a return value.
  
positive.code: 
  ;; Move out VM-SCOPE if it contains something. Otherwise keep NIL.
  (defun expex-move-arg-vm-scope (ex x)
    (let s (expex-funinfo-env-add)
      (aif (vm-scope-body x)
           (cons (append `((%var ,s))
  		               (expex-body ex ! s))
  		       s)
  	     (cons nil nil))))
  
  (defun expex-move-arg-std (ex x)
    (with (s (expex-funinfo-env-add)
      	 (moved new-expr) (expex-expr ex x))
        (cons (append `((%var ,s))
  					moved
  		    		(if (expex-returnable? ex new-expr.)
  		        		(list (expex-guest-filter-setter ex
  
negative.code:        (not (expex-in-env? x))
         (global-variable? x)))
  
  (defun expex-funinfo-env-add-var ()
    (let s (expex-sym)
      (awhen *expex-funinfo*
        (funinfo-env-add ! s))
  	s))
  
  (defun expex-funinfo-env-add-stack ()
    (aif *expex-funinfo*
        (funinfo-make-stackplace ! (expex-sym))
    	  (expex-sym)))
  
  (defun expex-stack-locals? (ex)
    (and *expex-funinfo* ; Is set if we're inside a function.
  	   (transpiler-stack-locals? (expex-transpiler ex))))
  
  (defun expex-funinfo-env-add (ex)
    (if (expex-stack-locals? ex)
  	  (expex-funinfo-env-add-stack)
  	  (expex-funinfo-env-add-var)))
  
  (defun expex-local-decl (ex s)
    (unless (expex-stack-locals? ex)
  	`((%var ,s))))
  
  ;;;; PREDICATES
  
  