Array from INSERT .. RETURNING in plpgsql?

Ok, so the following works:

pagila=# select array(select s.i from generate_series(1, 10) s(i));
?column?
------------------------
{1,2,3,4,5,6,7,8,9,10}
(1 row)

but this doesn't:

pagila=# create or replace function testfun() returns void as $$
declare
vals int[];
query text;
begin
query := 'insert into test select s.i from generate_series(1,10)
s(i) returning i;';
execute query into vals;
raise notice 'vals dim: %', array_upper(vals, 1);
raise notice 'vals[3]: %', vals[3];
end;
$$ language plpgsql;
CREATE FUNCTION
Time: 3.319 ms
pagila=# select testfun();
ERROR: array value must start with "{" or dimension information
CONTEXT: PL/pgSQL function "testfun" line 6 at execute statement

Is there any way to do what I'm trying without explicity looping over
the results of the insert?

Erik Jones, Database Administrator
Engine Yard
Support, Scalability, Reliability
(415) 963-4410 x 260
Location: US/Pacific
IRC: mage2k