could not find array type for data type character varying[]

Hi,

I'm trying to aggregate a list of table attributes into an array.

The actual code looks something like this:

  SELECT
    node_ref AS id,
    array_agg(DISTINCT ARRAY[namespace, name, value]) as annotations
  ...
  GROUP BY id;

I guess the minimal example that reproduces the error is:

  annis=> select array_agg(array['a'::varchar, 'b', 'c']);
  ERROR:  could not find array type for data type character varying[]

Why doesn't this work?

Cheers,
Viktor