On Sat, Nov 7, 2015 at 3:28 AM, Eli Zaretskii <eliz@gnu.org> wrote:
>> global-highlight-parentheses-mode puts overlays in every buffer.
>
> Does it really mean to do that in *Messages*?  If not, perhaps we
> should suggest to the developers of highlight-parentheses to exempt
> *Messages* from that, as that buffer is pretty specialized anyway.  In
> particular, due to the way the message logging in *Messages* is
> implemented, the overlay modification hooks will only ever be called
> in that buffer with AFTER non-nil, and even that will only happen when
> Emacs decides to delete some text from *Messages*; inserting a new
> message there will never call the overlay modification hooks.

Well, I suppose users may want parentheses highlighted in messages too.

But note that the overlays created by highlight-parentheses-mode do
*not* have any modification-hooks. It's the triggering
modification-hooks of (yasnippet's) overlays in another buffer in
addition to the existence of (highlight-parentheses') overlays in
*Messages* that triggers the bug.

> Yes, this looks good to me.  How about creating a new file
> buffer-tests.el (the offending code is in buffer.c)?

Okay, see attached.