BUG #5982: recursive type crashes postgres

The following bug has been logged online:

Bug reference:      5982
Logged by:          Rikard Pavelic
Email address:      rikard.pavelic@zg.htnet.hr
PostgreSQL version: 9.1.alpha5
Operating system:   Windows XP SP3
Description:        recursive type crashes postgres
Details:

CREATE TYPE turtle AS
(
    name varchar
);
ALTER TYPE turtle ADD ATTRIBUTE offspring turtle;

CREATE TABLE turtles
(
    id int,
    tortoise turtle
);