bug#23534: Failing to recognize -- as comment-starter

[Eli Zaretskii]

> From: Stefan Monnier <monnier@IRO.UMontreal.CA>
> Date: Fri, 13 May 2016 16:28:06 -0400
> 
> Put the following in bug-mode.el:
> 
>     (defvar bug-mode-syntax-table
>       (let ((st (make-syntax-table)))
>         (modify-syntax-entry ?- "_ 123" st)
>         (modify-syntax-entry ?\n ">" st)
>         st))
>     
>     (define-derived-mode bug-mode prog-mode "BUG"
>       "Major mode to exhibit the bug."
>       (setq-local font-lock-defaults '(nil))
>       (insert "-- hello\n"))
> 
> And then
> 
>     emacs -Q -l bug-mode.el -f bug-mode
> 
> In Emacs-24.5 (and emacs-25) you then see "-- hello" highlighted as
> a comment, but on "master" this stays in default face.

It is highlighted as a comment with the current master, so I guess the
bug was solved in the meantime.

Thanks.