anchor.diff:            (let ((prev-file nil))
               (with-sourcelist (sourcelist "*definitions*")
                 (dolist (location locations)
  -                (let ((file (filespec-to-file (xref-location-filespec location)))
  +                (let ((file (filespec-to-filename (xref-location-filespec location)))
                         (title (xref-location-title location)))
                     (append-sourcelist sourcelist
                                        (lambda (p)
  
positive.code:     (string (find-file-buffer filespec))
      (pathname (find-file-buffer filespec))))
  
  (defun filespec-to-file (filespec)
    (etypecase filespec
      (buffer (buffer-filename filespec))
      (string filespec)
      (pathname filespec)))
  
  (defun go-to-location (location &optional pop-to-buffer)
    (let ((buffer (filespec-to-buffer (xref-location-filespec location))))
  
negative.code:    :newline-and-indent
     :indent-region
     :make-xref-location
     :make-xref-references
     :xref-location-filespec
     :xref-location-position
     :xref-location-title
     :xref-references-type
     :xref-references-locations
     :filespec-to-buffer
     :filespec-to-filename))
  (in-package :lem.language-mode)
  
  (define-editor-variable line-comment nil)
  