anchor.diff:  (defun form-value (form &key (reduce-use-count t))
     "Return the value of form wrapped in quote if its known, otherwise return nil."
     (cond ((or (and (consp form)
  -		  (eql (first form) 'quote))
  +		  (member (first form) '(quote function)))
   	     (lambda-information-p form))
   	 form)
   	((lexical-variable-p form)
  
positive.code: 		   (or (and (lambda-information-p val)
                              (<= (getf (lambda-information-plist val) 'copy-count 0)
                                  *constprop-lambda-copy-limit*))
  		       (and (consp val) (eq (first val) 'quote))
  		       (and (lexical-variable-p val)
  			    (localp val)
  			    (eql (lexical-variable-write-count val) 0))))
  
negative.code:                         (<= (getf (lambda-information-plist (third form)) 'copy-count 0)
                              *constprop-lambda-copy-limit*))
                     (and (consp (third form))
                          (member (first (third form)) '(function quote))))
                 ;; Always propagate the new value forward.
                 (setf (second info) (third form))
                 ;; The value is constant. Attempt to push it back to the
  