bug#57481: elisp code utilising derived-mode-parent

[Phil Sainty]

On 2022-08-31 01:16, Christopher Dimech wrote:
> It could find things through and do what it has to do,
> without requirements for user mode loading.

Except that what it needs to do is load the mode.

If you're now saying that you're actually happy for the mode
to be loaded just so long as the user doesn't have to do it
themselves, then you can do that for autoloaded modes.
Check autoloadp and, if non-nil, call autoload-do-load.

For modes which are neither loaded nor known as autoloads,
Emacs doesn't even know they exist, let alone how to tell
you what they derive from.