anchor.diff:  		  (call-next-method ast
   				    (context (list (make-temp))
   					     successors
  -					     (invocation context)))))
  +					     invocation))))
   	     (t
   	      ;; We have at least one result.  In case there is more
   	      ;; than one, we generate a successor where all but the
  
positive.code: 		(call-next-method ast
  				  (context (list (first results))
  					   (list successor)
  					   (invocation context)))))))
        (2
         ;; We have a context where a test of a Boolean is required.  We
         ;; create a new context where the result is compared to NIL
  
negative.code: 				 (list temp)
  				 results
  				 (first successors)))
  			  invocation))))
  	     ((null results)
  	      ;; We don't need the result.  This situation typically
  	      ;; happens when we compile a form other than the last of
  