regtype sorting broken in 8.3

This used to work in 8.2:

pei=# select castsource::regtype, casttarget::regtype, castcontext from pg_cast order by 1,2;

But int 8.3 it says:

ERROR:  XX000: could not find pathkey item to sort
LOCATION:  make_sort_from_pathkeys, createplan.c:2812

-- 
Peter Eisentraut
http://developer.postgresql.org/~petere/