array exclusion constraints

CREATE TABLE test (
foo text[],
EXCLUDE USING gist (foo WITH &&)
);

ERROR: data type text[] has no default operator class for access method "gist"
HINT: You must specify an operator class for the index or define a default operator class for the data type.

It looks like exclusion constraints don't work with arrays, there's no gist opclass for them. This would be a nice to have feature and, if I recall correctly, exclusion constraints were meant to work both with ranges and arrays. Am I missing something?

Regards,
Francis