Re: Default lexical-binding to t

[Eli Zaretskii]

> From: Stefan Monnier <monnier@iro.umontreal.ca>
> Cc: rms@gnu.org,  emacs-devel@gnu.org
> Date: Tue, 05 Nov 2024 15:24:07 -0500
> 
> > What bothers me is how do I know whether a given Lisp file of mine
> > will have problems under lexical-binding.  Do we have any tools which
> > will help me determine that?
> 
> It's generally impossible to do that reliably (it can be reduced to
> a variant of the halting problem), but the problem is exactly the same
> as that of converting from dynbind to lexbind (which we do describe in
> the manual).

Too bad.

> IOW, nothing beats actually testing the code, IME.  In 99% of the cases,
> changes introduced by the switch will manifest as "void variable" errors.

Consider the plight of someone who over the years have accrued
hundreds of lines of Lisp in their init and customization files, and
now needs somehow to walk over all of that and see if anything needs
changing, or risk breakage in something that has been working for
eons.  It would be nice if we could help those poor souls, and not
just hang them to dry.