From: Tom Lane <tgl@sss.pgh.pa.us>
To: rekgrpth@gmail.com
cc: pgsql-bugs@lists.postgresql.org
Subject: Re: BUG #17916: Expression IN list translates to unqualified operator
In-reply-to: <17916-8d713fd64529da21@postgresql.org>
References: <17916-8d713fd64529da21@postgresql.org>
Comments: In-reply-to PG Bug reporting form <noreply@postgresql.org>
	message dated "Wed, 03 May 2023 05:19:07 -0000"
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Date: Wed, 03 May 2023 09:40:44 -0400
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PG Bug reporting form <noreply@postgresql.org> writes:
> create operator qwe.= (leftarg = char, rightarg = text, function =
> qwe.chartexteq, commutator = operator(qwe.=), hashes, merges);
> set search_path = qwe;
> explain (costs off, verbose on) select i from generate_series(1, 10) i where
> i::char in (2::text);

> I expected, that IN list translates to pg_catalog.=

Why would you expect that?  It'd make it impossible to use IN
with user-defined data types.  In this case, you made an operator
that is a closer match to the given datatypes (ie, "char = text")
than the native "text = text" operator, so it used that one.

I've not checked the code, but my recollection is that X IN (Y) just
resolves to the same equality operator you'd get by writing X = Y.
There's been some discussion about allowing a schema qualifier to
be included in the syntax, but nothing's been done about that.

			regards, tom lane