after-change-functions wrongly accepts functions with three args only
Issue is explained in docstring of workaround below.
If the function to be hooked in --save-buffer-- doesn't require args, add-hook resp. after-change-functions should not.
(defun my-instant-save-buffer (eins zwei drei)
"To be hooked into list `after-change-functions'
`after-change-functions' expects functions receiving three arguments.
Arguments are ignored here, but slots needed by add-hook"
(add-hook 'after-change-functions 'my-instant-save-buffer)