Re: cc-mode fontification feels random

[Eli Zaretskii]

> From: Stefan Monnier <monnier@iro.umontreal.ca>
> Cc: acm@muc.de,  dancol@dancol.org,  emacs-devel@gnu.org
> Date: Sun, 06 Jun 2021 14:18:15 -0400
> 
> > So if the first windowful of a file that's displayed is at EOB,
> > fontification must go all the way back to BOB and start scanning
> > there, until it comes to the end?
> 
> Yup.  The way to make it bearable is to make that scan be as simple and
> fast as possible.
> 
> Note that `syntax-propertize` and `syntax-ppss` also work this way, so
> it's already the case that when we start by displaying EOB we first have
> to apply `syntax-propertize` over the whole buffer :-(

What exactly are the reasons that we need to scan from BOB?  With the
exception of data type declarations, what else requires to go back
farther that the beginning of the defun in which we start fontifying?