Re: Has lexical binding declaration format changed in Emacs 30 or 31?

Pierre Rouleau <[email protected]> writes:

> Hi all,
>
> I started seeing the byte compiler generating the
>
> "Warning (bytecomp): file has no ‘lexical-binding’ directive on its first
> line"
>
> for files that do have the declaration.
>
> For example, the file:
> gnu-elpa-keyring-update-2025.10.1/gnu-elpa-keyring-update.el
>
> The first line of the file seems OK to me:
>
> ;;; gnu-elpa-keyring-update.el --- Update Emacs's GPG keyring for GNU ELPA
>  -*- lexical-binding: t; -*-
>
> I have seen this on
> GNU Emacs 30.2.50 (build 2, aarch64-apple-darwin23.6.0, NS appkit-2487.70
> Version 14.8.2 (Build 23J126)) of 2025-11-26
>
> Has the format requirement changed for Emacs 30 or 31?

See the NEWS file (C-h n) for Emacs 30:

   *** Warn about missing 'lexical-binding' directive.
   The compiler now warns if an Elisp file lacks the standard
   '-*- lexical-binding: ... -*-' cookie on the first line.
   This line typically looks something like

   ;;; My little pony mode  -*- lexical-binding: t -*-

So, the format has not changed and there appears to be some
other problem.  You could try ‘emacs -Q’ and then read and
compile your file to see whether you can reproduce the
problem.

Also, the command ‘elisp-enable-lexical-binding’ inserts the
‘-*- lexical-binding: t -*-’ into a buffer and sets
‘lexical-binding’ to t.  Try:

   M-x e-e-l-b

This is more evidence that the format has not changed.

-- 
The lyf so short, the craft so long to lerne.
- Geoffrey Chaucer, The Parliament of Birds.