PATCH: resolved an issue occured in cast creation

Hi,

I have resolved an issue, occurred while creating a new cast.

ISSUE:

While creating a new cast, when user select source type and target type,
below query is used to fetch the function list related to that cast.

SELECT proname, nspname
FROM pg_proc p JOIN pg_namespace n ON n.oid=pronamespace
WHERE proargtypes[0] = <oid of source type>
*AND proargtypes[1] = 0 *
AND prorettype = <oid of target type>

In this query "proargtypes" contains argument type list.
As you can see above proargtypes[1] (2nd argument to function ) is compared
to 0 (in bold)

But according to postgresql standard, "proargtypes" field comparison should
be like this :

proargtypes[1] (if present) should be compared to 23 (int4),
and proargtypes[2] (if present) should be compared to 16 (bool).

I have resolved the issue and patch is attached with this mail.

Please do review it and let me know in case of anything is missing.

Regards,
Sanket Mehta
Sr Software engineer
Enterprisedb