BUG #4135: postmaster crashes if matching on VALUES is used on a column with index

The following bug has been logged online:

Bug reference: 4135
Logged by: Miernik
Email address: public(at)miernik(dot)name
PostgreSQL version: 8.3.1
Operating system: Linux polica 2.6.20-xen-r6 #2 SMP Wed Jan 16 19:43:41
CET 2008 i686 GNU/Linux
Description: postmaster crashes if matching on VALUES is used on a
column with index
Details:

The simplest set of commands to reporoduce the crash I could find is
attached below. I hope it is self-explanatory. If you can't reporoduce it,
please e-mail me and I'll try to give more info. Please also e-mail me if
you happen to fix this bug. Thank you for your great work.

$ createdb test1
$ psql test1
Pager is always used.
Welcome to psql 8.3.1, the PostgreSQL interactive terminal.

Type: \copyright for distribution terms
\h for help with SQL commands
\? for help with psql commands
\g or terminate with semicolon to execute query
\q to quit

SSL connection (cipher: DHE-RSA-AES256-SHA, bits: 256)

test1=> SELECT version();
version
----------------------------------------------------------------------------
------------
PostgreSQL 8.3.1 on i486-pc-linux-gnu, compiled by GCC cc (GCC) 4.2.3
(Debian 4.2.3-2)
(1 row)
test1=> CREATE TABLE foo (bar numeric(1));
CREATE TABLE
test1=> CREATE INDEX foo_idx ON foo(bar);
CREATE INDEX
test1=> INSERT INTO foo VALUES (1);
INSERT 0 1
test1=> SELECT bar FROM foo;
bar
-----
1
(1 row)

test1=> SELECT bar FROM foo WHERE bar = 1;
bar
-----
1
(1 row)

test1=> SELECT bar FROM foo WHERE bar IN (VALUES (1));
server closed the connection unexpectedly
This probably means the server terminated abnormally
before or while processing the request.
The connection to the server was lost. Attempting reset: Succeeded.

test1=>

tail -f /var/log/postgresql/postgresql-8.3-main.log
2008-04-30 23:46:08 CEST LOG: server process (PID 4121) was terminated by
signal 11: Segmentation fault
2008-04-30 23:46:08 CEST LOG: terminating any other active server
processes
2008-04-30 23:46:08 CEST LOG: all server processes terminated;
reinitializing
2008-04-30 23:46:08 CEST LOG: database system was interrupted; last known
up at 2008-04-30 23:43:38 CEST
2008-04-30 23:46:08 CEST LOG: database system was not properly shut down;
automatic recovery in progress
2008-04-30 23:46:08 CEST LOG: redo starts at 3/8B7F846C
2008-04-30 23:46:08 CEST LOG: record with zero length at 3/8B810B6C
2008-04-30 23:46:08 CEST LOG: redo done at 3/8B810B40
2008-04-30 23:46:08 CEST LOG: last completed transaction was at log time
2008-04-30 23:45:42.858855+02
2008-04-30 23:46:08 CEST LOG: database system is ready to accept
connections