anchor.diff:  	   (setf (id-map pcache)
   		 (delete r (id-map pcache)
   			 :key #'car
  -			 :test output-record-id-test r)))))
  +			 :test (output-record-id-test r))))))
      record
      t))
   
  
positive.code: 
  (defmethod invoke-updating-output ((stream updating-output-stream-mixin)
  				   continuation
  				   (record-type
  				    (eql 'standard-updating-output-record))
  				   unique-id id-test cache-value cache-test
  				   &key (fixed-position nil) (all-new nil)
  				   (parent-cache nil))
    (unless *enable-updating-output*
      (return-from invoke-updating-output (funcall continuation stream)))
    (let ((parent-cache (or parent-cache *current-updating-output* stream)))
      (with-accessors ((id-map id-map))
          parent-cache
  
negative.code: 	(cond ((or all-new (null record))
  	       ;; This case covers the outermost updating-output too.
  	       (with-new-output-record (stream
  					record-type
  					*current-updating-output*
  					:unique-id unique-id
  					:id-test id-test
  