BUG #16048: SQLSTATE 22P05 is not captured in exception clause

The following bug has been logged on the website:

Bug reference: 16048
Logged by: Fabio Henrique Gibon
Email address: fabiogibon(at)gmail(dot)com
PostgreSQL version: 12.0
Operating system: Windows
Description:

Hi,

I have a database using LATIN1 (and I can't change it), so, when the
user informar a invalid character it is not captured in exception clause.
See a short sample:

DO $$
DECLARE
v varchar;

BEGIN

v := 'ABCŸ';

EXCEPTION

WHEN others THEN
RAISE INFO 'Error State: %', SQLSTATE;

END$$;

I tried in old versions (9.0, 9.6,...) and the result is the same. The error
is propagated, disregarding the exception treatement.