is not distinct from any(...)

["Robert Haas" <robertmhaas@xxxxxxxxx>]

I'm trying to write a SQL statement to determine whether a value is an
an array, but I want the comparison to be done using IS NOT DISTINCT
FROM rather than =.

My first thought was that instead of writing:

SELECT value = ANY(array)

...I could simply write:

SELECT value IS NOT DISTINCT FROM ANY(array)

That doesn't seem to work, because IS NOT DISTINCT FROM is not an
operator.  So then I tried creating an operator === (anyelement,
anyelement) that just does IS NOT DISTINCT FROM and writing:

select 1 === any(array[1]);

which got me:

ERROR:  could not find array type for data type anyelement

Grr... any suggestions?

...Robert