anchor.diff:    (setf (predecessors (gethash instruction (instruction-info *program*)))
   	new))
   
  -(defmethod procedure ((instruction sicl-mir:instruction))
  -  (assert (not (null *program*)))
  -  (procedure (gethash instruction (instruction-info *program*))))
  -
  -(defmethod (setf procedure) (new (instruction sicl-mir:instruction))
  -  (assert (not (null *program*)))
  -  (setf (procedure (gethash instruction (instruction-info *program*)))
  +(defmethod owner ((instruction sicl-mir:instruction))
  +  (assert (not (null *program*)))
  +  (owner (gethash instruction (instruction-info *program*))))
  +
  +(defmethod (setf owner) (new (instruction sicl-mir:instruction))
  +  (assert (not (null *program*)))
  +  (setf (owner (gethash instruction (instruction-info *program*)))
   	new))
   
   (defmethod basic-block ((instruction sicl-mir:instruction))
  
positive.code:   (setf (basic-block (gethash instruction (instruction-info *program*)))
  	new))
  
  (defmethod pre-locations ((instruction sicl-mir:instruction))
    (assert (not (null *program*)))
    (pre-locations (gethash instruction (instruction-info *program*))))
  
  (defmethod (setf pre-locations) (new (instruction sicl-mir:instruction))
    (assert (not (null *program*)))
    (setf (pre-locations (gethash instruction (instruction-info *program*)))
  	new))
  
  (defmethod post-locations ((instruction sicl-mir:instruction))
    (assert (not (null *program*)))
    (post-locations (gethash instruction (instruction-info *program*))))
  
  (defmethod (setf post-locations) (new (instruction sicl-mir:instruction))
    (assert (not (null *program*)))
    (setf (post-locations (gethash instruction (instruction-info *program*)))
  	new))
  
  (defun successors (instruction)
    (sicl-mir:successors instruction))
  
  
negative.code:       (let ((sorted-code
  	      (sort (copy-list procedures) #'< :key #'nesting-depth)))
  	(loop for procedure in sorted-code
  	      do (compute-lexical-depth procedure))))))
  
  (defun ensure-lexical-depths (program)
    (when (>= (ensure-location-ownership program)
  	    (lexical-depths-timestamp program))
      (compute-lexical-depths program)
      (setf (lexical-depths-timestamp program)
  	  (incf (current-timestamp program))))
    (lexical-depths-timestamp program))
  
  ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
  ;;;
  