bug#74145: 31.0.50; Default lexical-binding to t

[Stefan Monnier via "Bug reports for GNU Emacs, the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>]

> Thanks, but this kind of change cannot be discussed here.  Please
> start a discussion on emacs-devel, and please include in your

I posted something there, but to be honest at this point I don't think
discussion is going to be useful.

Also, I'm doing this now, i.e. early in the Emacs-31 development cycle,
so that we get a chance to get as much feedback as possible before
committing to it in a release: the patch is easy to revert since (beside the
doc) it's a matter of changing

    Vlexical_binding = Qt;

back to

    Vlexical_binding = Qnil;

> In particular, any objections should be taken very seriously,

I'm not sure what that means concretely.

> and perhaps some follow-up measures should be included in the
> changeset to make the transition smoother and easier.

I think we've already done about as much as we could over the past
several years.  Maybe after installing the patch we will discover new
cases which warrant further changes, but I doubt we'll be able to figure
that out via discussions on emacs-devel.


        Stefan