anchor.diff:     `(subset-completion ,sequence ,@(and testp `(:test ,test)))
      :name-key name-key
      :documentation-key documentation-key
  -   :partial-completers partial-completers)
  +   :partial-completers partial-completers
  +   :printer printer
  +   :highlighter highlighter)
     :options #.+completion-options+)
   
   (define-presentation-type-abbreviation subset-alist (alist
  
positive.code:             documentation-key
              (partial-completers '(#\Space))
              (separator #\,)
              (echo-space t))
    :inherit-from t)
  
  (define-presentation-method presentation-typep (object
  
negative.code:                 :value-key member-alist-value-key)
     :name-key name-key
     :documentation-key documentation-key
     :partial-completers partial-completers
     :printer printer
     :highlighter highlighter)
    :options ((name-key 'default-completion-name-key)
              (documentation-key 'member-alist-doc-key)
              (partial-completers '(#\Space))
              (printer #'write-token)
              (highlighter #'highlight-completion-choice)))
  
  (define-presentation-type subset-completion (sequence
                                               &key (test 'eql)
  