cassert: array size exceeds the maximum allowed (134217727)

I'm getting a failed assertion on 8.4b1. With cassert off it crashes
the postmaster. The assertion is:
ERROR: array size exceeds the maximum allowed (134217727)

Here is the query:
select * from (select generate_series(1,500) as id) c left outer
join foo_status a on c.id = a.id;

note: replacing generate_series with table still gives the error.

create or replace view foo_status as
select * from
(
select foo_id as id,
array_to_string(array_agg(jc.name), ', ') as jc_list
from foo_session
left join (select * from bat where finished is null) q
using (foo_id)
left join bar using (bar_id)
left join baz jc using (baz_id)
where stop is null
group by id, session_start, adb_pid
) q;

all the tables are quite small. foo status runs fine normally and
returns in a couple of msec.

merlin