Bug in Pari 2.5.0

[Dirk Laurie <dirk.laurie@gmail.com>]

Yes, I know. 2.5.0 is not the most recent stable version.
But it is the version distributed with Ubuntu 12.04 LTS,
a system that will be supported until April 2017, so
I thought it worth reporting.

Apologies if an update was published after May 29, 2013,
which is when I last safe-upgraded my Ubuntu Precise.

 $ gp
Reading GPRC: /etc/gprc ...Done.

                 GP/PARI CALCULATOR Version 2.5.0 (released)
             i686 running linux (ix86/GMP kernel) 32-bit version
       compiled: Nov 17 2011, gcc-4.6.2 (Ubuntu/Linaro 4.6.2-2ubuntu1)
                (readline v6.2 enabled, extended help enabled)

                    Copyright (C) 2000-2011 The PARI Group

PARI/GP is free software, covered by the GNU General Public License, and
comes WITHOUT ANY WARRANTY WHATSOEVER.

Type ? for help, \q to quit.
Type ?12 for how to get moral (and possibly technical) support.

parisize = 4000000, primelimit = 500509
? x=B; y=C;
? print(subst(A/Q*B,Q,B),"   ",subst(A*Q*B,Q,B))
0   A*B^2

That '0' should be 'A'.