Backend crash trying to delete rows

Andrea Aime (aaime(at)comune(dot)modena(dot)it) reports a bug with a severity of 3
The lower the number the more severe it is.

Short Description
Backend crash trying to delete rows

Long Description
Platform: RedHat 6.2, PostgreSQL 7.02 compiled by gcc egcs 2.91.66,
running on a PIII 733Mhz, 128 MB RAM, 9 GB SCSI HD.

Create an empty database and then two table, a master and a slave,
slave references master primary key with an on delete cascade
fk option. Everything runs fine, when you delete rows in master
table you get also corresponding slave rows deleted. Now rename
slave into slave2 and retry delete: backend crashes.
FK are part of table structure, you can implement them as trigger
but they must follow any table modification, otherwise schema
evolution is not possible.

Sample Code
I put here some code just to give you an idea, I haven't
tried it.

create table master(
id_master serial,
name varchar,
primary key(id_master)
);

create table slave(
id_slave serial,
id_master int4,
primary key(id_slave),
foreign key(id_master) references master(id_master) on delete cascade
);

insert into master(name) values('Andrew');
insert into slave(id_master,slave) values(1,'Rod');

#this one works fine
delete from master;

alter table slave rename to slave2;

insert into master(name) values('Andrew');
insert into slave(id_master,slave) values(2,'Rod');

#boom!
delete from master;

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