anchor.diff:                          (<= (getf (lambda-information-plist (third form)) 'copy-count 0)
                               *constprop-lambda-copy-limit*))
                      (and (consp (third form))
  -                        (eq (first (third form)) 'quote)))
  +                        (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
  
positive.code: (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))
  	     (lambda-information-p form))
  	 form)
  	((lexical-variable-p form)
  
negative.code: 		   (or (and (lambda-information-p val)
                              (<= (getf (lambda-information-plist val) 'copy-count 0)
                                  *constprop-lambda-copy-limit*))
  		       (and (consp val)
                              (member (first val) '(quote function)))
  		       (and (lexical-variable-p val)
  			    (localp val)
  			    (eql (lexical-variable-write-count val) 0))))
  