bug#64272: 28.1; lisp_file_lexically_bound_p behavior mismatches file local variables

[Eli Zaretskii]

> From: Stefan Monnier <monnier@iro.umontreal.ca>
> Cc: LdBeth <andpuke@foxmail.com>,  64272@debbugs.gnu.org
> Date: Sun, 25 Jun 2023 09:37:31 -0400
> 
> > I'm not sure we want to support this outside of a Lisp comment.
> > Stefan, WDYT?  Could false positives cause harm?
> 
> I'd much rather we try and stay as close as possible to the behavior of
> `hack-local-variables-prop-line`

Right, but that doesn't require the -*- line to be a comment:

      (goto-char (point-min))
      (let ((end (set-auto-mode-1))
            result)
        (cond ((not end)
               nil)
              ((looking-at "[ \t]*\\([^ \t\n\r:;]+\\)\\([ \t]*-\\*-\\)")
               ;; Simple form: "-*- MODENAME -*-".
               (if (eq handle-mode t)
                   (intern (concat (match-string 1) "-mode"))))
              (t
               ;; Hairy form: '-*-' [ <variable> ':' <value> ';' ]* '-*-'
               ;; (last ";" is optional).
               ;; If HANDLE-MODE is t, just check for `mode'.
               ;; Otherwise, parse the -*- line into the RESULT alist.

The fact that most -*- lines are in comments is because they are in
program source files, so we need to hide them from the compiler or the
interpreter.

Am I missing something?