anchor.diff:        (unless locations
           (editor-error "No definitions found"))
         (push-location-stack (current-point))
  +      (setf locations (uiop:ensure-list locations))
         (if (null (rest locations))
             (go-to-location (first locations))
             (let ((prev-file nil))
  
positive.code:     (if pop-to-buffer
          (setf (current-window) (pop-to-buffer buffer))
          (switch-to-buffer buffer))
      (move-to-position (current-point) (xref-location-position location))))
  
  (define-command find-definitions () ()
    (alexandria:when-let (fn (variable-value 'find-definitions-function :buffer))
  
negative.code: 
  (defstruct xref-location
    (filespec nil :read-only t :type (or buffer string pathname))
    (position 1 :read-only t)
    (title "" :read-only t :type string))
  
  (defstruct xref-references
  