BUG #2087: Bogus error message on CREATE TRIGGER with a SQL function

The following bug has been logged online:

Bug reference:      2087
Logged by:          Jozef Behran
Email address:      jozef.behran@krs.sk
PostgreSQL version: 8.1.0
Operating system:   Short answer: Mandrake 10.2. Long answer: Linux sarkan
2.6.11-6mdk #1 Tue Mar 22 16:04:32 CET 2005 i686 AMD Athlon(tm) Processor
unknown GNU/Linux
Description:        Bogus error message on CREATE TRIGGER with a SQL
function
Details:

Here is a sample shell session showing the SQL file and
the output:

$ cat bug.sql
\set VERBOSITY verbose

BEGIN;

CREATE table pokus (
  id INT4,
  sval VARCHAR(100),
  sortsval VARCHAR(100),
  PRIMARY KEY(id)
);

CREATE FUNCTION tpokus(pokus) RETURNS pokus as $$
  SELECT $1.id,$1.sval,translate($1.sval,'abc','ABC');
$$ LANGUAGE SQL IMMUTABLE;

INSERT INTO pokus (id,sval) values (1,'aha');

SELECT tpokus(pokus.*) FROM pokus;

CREATE TRIGGER trigger_pokus
  BEFORE INSERT OR UPDATE
  ON pokus FOR EACH ROW
  EXECUTE PROCEDURE tpokus()
;

ROLLBACK;
$ psql -f bug.sql
BEGIN
psql:bug.sql:8: NOTICE:  CREATE TABLE / PRIMARY KEY will create implicit
index "pokus_pkey" for table "pokus"
CREATE TABLE
CREATE FUNCTION
INSERT 0 1
   tpokus
-------------
 (1,aha,AhA)
(1 row)

psql:bug.sql:22: ERROR:  function tpokus() does not exist
LOCATION:  LookupFuncName, parse_func.c:1192
ROLLBACK
$ _

The buggy error message is the line before `ROLLBACK' (the one saying that
`tpokus' does not exist). The problem is that there *is* a function named
`tpokus' (the previous SELECT executed the function without problems). If it
is impossible to use a SQL function in a trigger, the error message should
say so (for example ERROR: cannot use SQL function `name' in a trigger). If
it is possible to have SQL-only triggers but the code is wrong, you should
add a complete example of a SQL trigger into the documentation to show all
the nasty quirks that may get into the way (for example the documentation
says that the trigger must return `trigger' but it is impossible to declare
such a SQL function).