bug#16585: c-invalidate-state-cache fails if called when narrowed

[Alan Mackenzie]

Hi, Daniel.

On Tue, Jan 28, 2014 at 06:09:04PM -0800, Daniel Colascione wrote:
> c-invalidate-state-cache can fail if called in a narrowed region: we end 
> up calling c-clear-char-property for bob even if that's before 
> point-min, causing remote-text-properties to raise (args-out-of-range 1 2).

> We get into this situation when expanding yasnippet snippets; we're 
> calling c-invalidate-state-cache from c-before-change.

> To repro manually, first write this to some buffer.

> #include <stdio.h>

> void foo() {

> }


> Then (this is important) run M-x c-mode. After starting the mode, move 
> point to inside foo's body and eval (save-restriction (narrow-to-region 
> (point-at-bol) (point-at-eol)) (c-invalidate-state-cache (point))). You 
> should break into the debugger.

> The patch below seems correct and fixes the problem for me, but it'd be 
> nice if Alan could take a look at it before I push it to trunk. The 
> version of c-invalidate-state-cache in cc-mode trunk is very different.

I think I'd like to check that nothing can go awry in
c-invalidate-state-cache-1 with the widened buffer.  Give me a day or
two.

-- 
Alan Mackenzie (Nuremberg, Germany).