bug#16160: [PATCH] define-derived-mode clobbers syntax tables

[Daniel Colascione]

On 12/16/2013 11:17 AM, Stefan Monnier wrote:
> > 1) Visit shell script with comments. See comments fontified properly.
> > 2) M-x find-library sh-script RET
> > 3) M-x eval-buffer
> > 4) Return to shell script buffer
> > 5) C-x C-v RET
> > 6) Observe that comments are no longer fontified as comments.
>
> I can't reproduce it, starting from "emacs -Q".

I can't repro it either now, with or without -Q. That was odd. I know 
what I saw, and I know that my patch resolved the problem in that 
instance of Emacs, but I have no idea how defvar was clobbering that 
variable. I was able to repro it over an dover again though. I can only 
conclude that Emacs was punishing me for my many sins.

If I see it again, I'll try to hook Emacs up to a debugger. In the 
meantime, let's avoid changing fundamental infrastructure before a 
feature freeze.