anchor.diff:  		   (sicl-mir:make-nop-instruction nil))))
     (let ((next (if (null (results context))
   		  (car (successors context))
  -		  (compile-ast (sicl-ast:make-load-time-value-ast nil)
  -			       context))))
  +		  (sicl-mir:make-variable-assignment-instruction
  +		   (sicl-mir:make-external-input 'nil)
  +		   (car (results context))
  +		   (car (successors context))))))
       (loop for item in (reverse (sicl-ast:items ast))
   	  do (setf next
   		   (if (typep item 'sicl-ast:tag-ast)
  
positive.code: (defun make-temp (argument)
    (cond ((typep argument 'sicl-env:lexical-location-info)
  	 argument)
  	((typep argument 'sicl-ast:word-ast)
  	 (sicl-mir:make-immediate-input (sicl-ast:value argument)))
  	(t
  	 (new-temporary))))
  
  
negative.code:   (loop with succ = successor
  	for arg in (reverse arguments)
  	for temp in (reverse temps)
  	do (unless (or (typep temp 'sicl-mir:immediate-input)
  		       (typep temp 'sicl-mir:external-input))
  	     (setf succ (compile-ast arg (context (list temp) (list succ)))))
  	finally (return succ)))
  
  ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
  ;;;
  ;;; Compile a IMMEDATE-AST.
  ;;;
  
  (defmethod compile-ast ((ast sicl-ast:immediate-ast) context)
    (with-accessors ((results results)
  		   (successors successors))
        context
  