Listing headings in dedicated buffer with imenu.

[Heime <heimeborgia@protonmail.com>]

I wish to list headings in a dedicated buffer with imenu.  
The listing should be in the order in which headings occur 
in the buffer.

Have done the following, but the buffer ends up empty.

(defun vodil-imenu-bfh ()
  "Insert imenu headings in order in a dedicated buffer."
  (interactive)

  (let ((imenu-items (imenu--make-index-alist t))
        (buffer-name "*Imenu Headings*"))
    (with-current-buffer (get-buffer-create buffer-name)
      (erase-buffer)
      (dolist (item imenu-items)
        (let ((name (car item))
              (position (cdr item)))
          (when (and (stringp name) (number-or-marker-p position))
            (insert (format "%s\n" name)))))
      (goto-char (point-min)))
    (pop-to-buffer buffer-name)))