anchor.diff:      (when (eq item (funcall key (car rest)))
         (return rest))))
   
  -(defun |member-test-not=eq key=identity| (name item list)
  +(defun |member test-not=eq key=identity| (name item list)
     (with-proper-list-rests (rest list name)
       (when (not (eq item (car rest)))
         (return rest))))
   
  -(defun |member-test-not=eq key=other| (name item list key)
  +(defun |member test-not=eq key=other| (name item list key)
     (with-proper-list-rests (rest list name)
       (when (not (eq item (funcall key (car rest))))
         (return rest))))
  
positive.code:   
  ;;; Special case when test is eq and key is given.
  
  (defun sublis-eq-key (alist tree key)
    (let ((substitution-p nil))
      (labels ((traverse (tree)
  	       (let ((entry (with-alist-elements (element alist sublis)
  
negative.code: 
  ;;; Special version if test is eq and key is given.
  
  (defun |subst key=other test=eq| (new old tree key)
    (labels ((traverse (tree)
               (cond ((eq (funcall key tree) old) new)
                     ((atom tree) tree)
  