bug#25309: 11.89.8; multi-level script fontification stacks incorrectly

[Tassilo Horn]

Mosè Giordano <address@hidden> writes:

Hi Gennady, Uwe & Mosè,

[CC'ing Uwe because I know he uses this feature.]

>> The multi-level fontification was introduced by
>> Tassilo Horn with commit 513490f on 2015-09-03.
>
> Wow, I didn't even remember such change!  My memory is failing :-(
>
> Tassilo, when/if you have time (I don't want to break your holidays
> ;-), could you please give a look at this?

I just had a look and Gennady is correct in that there is an issue here
although what I get is a bit different from his observations.

With `font-latex-fontify-script' set to 'multi-level or 'invisible, what
I expect in $a^b^c$ is that the b is raised above a and a bit smaller,
and c is raised above b and again a bit smaller.  What I actually see is
that b is raised above a and a bit smaller but c is raised to the very
same height as b and has b's size.

Sadly, I have no clue why that's the case.  The code worked as intended
when I wrote it and there haven't been any changes to it AFAICS.  Maybe
something is Emacs changed?  I've tried Emacs 25.1 and master with the
same results.

Does anyone of you have an older Emacs copy (22.x, 23.x, 24.x) installed
and can check what the results are with that?

Bye,
Tassilo