The code used
    return (Selectivity) 0.0;
where
    PG_RETURN_FLOAT8(0.0);
would be correct.
On 64-bit systems, these are pretty much equivalent, but on 32-bit
systems, PG_RETURN_FLOAT8() correctly produces a pointer, but the old
wrong code would return a null pointer, possibly leading to a crash
elsewhere.
We think this code is actually not reachable because bqarr_in won't
accept an empty query, and there is no other function that will
create query_int values.  But better be safe and not let such
incorrect code lie around.
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://www.postgresql.org/message-id/flat/8246d7ff-f4b7-4363-913e-827dadfeb145%40eisentraut.org
		
	
PostgreSQL Database Management System
This directory contains the source code distribution of the PostgreSQL database management system.
PostgreSQL is an advanced object-relational database management system that supports an extended subset of the SQL standard, including transactions, foreign keys, subqueries, triggers, user-defined types and functions. This distribution also contains C language bindings.
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General documentation about this version of PostgreSQL can be found at https://www.postgresql.org/docs/17/. In particular, information about building PostgreSQL from the source code can be found at https://www.postgresql.org/docs/17/installation.html.
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