bug#19535: 25.0.50; incorrect cursor display at EOB

[Eli Zaretskii]

> Date: Thu, 8 Jan 2015 15:48:26 +0900
> From: Syohei Yoshida <syohex@gmail.com>
> 
> I have same problem.
> 
> This bug was introduced at bc78ff2603b.
> I cannot reproduce revision 58f2d6ef32b28a787.
> 
> 
> 2015-01-08 11:20 GMT+09:00 Mark Oteiza <mvoteiza@udel.edu>:
> >
> > Hi,
> >
> > Somewhere between c477f20 and 88bc833 (10 commits), the cursor appears
> > to be displayed incorrectly when navigating to the last line of a
> > buffer.  For instance,
> >
> > 1. emacs -nw -Q
> > 2. ^P
> > 3. ^N
> >
> > Cursor is now shown at the last column of the frame.  Insert `C-x 3`
> > between steps 1 and 2, and one should notice the cursor being displayed
> > in the wrong window.

Yes, this is fallout from the "Qnil is zero" change.  The display
engine relied on the fact that a zero value in C was a Lisp integer,
but now it's a symbol, and all hell broke lose.

Fixed in commit daa18b5.

Thanks.