Just recently I upgraded from Postgresql 8.4.11 to 9.1.3. I used pg_dump in the process. Now I'm getting an error:
ERROR: no collation was derived for column "vin" with collatable type citext
HINT: Use the COLLATE clause to set the collation explicitly.
This is a continuation of the problem that I had earlier. It seems the fix suggested in the Release Notes did not catch custom domains. It seems as if the CREATE DOMAIN statement in 8.4 didn't even support the COLLATE clause.
This is how I created the vin type,
CREATE DOMAIN inventory.valid_vin AS citext
CHECK ( inventory.valid_vin( VALUE ) );