Unexpected results when Using `RIGHT JOIN`

[suyZhong]

Consider the test cases below. It is unexpected that the following queries all return 1, since NULL IS NOT NULL and NULL IS NULL could not be evaluated to true at the same time.

CREATE TABLE t0(c0 INT);
CREATE TABLE t1(c1 INT);
INSERT INTO t1 (c1) VALUES (1);
SELECT * FROM t0 RIGHT JOIN t1 ON 1; -- NULL 1

-- At least one of the query should return empty result
SELECT * FROM t0 RIGHT JOIN t1 ON 1 WHERE (NULL IS NOT NULL); -- NULL 1
SELECT * FROM t0 RIGHT JOIN t1 ON 1 WHERE (NULL IS NULL); -- NULL 1

Here's the version I used:

docker run -i -t pkleef/virtuoso-opensource-7 version

[pkleef/virtuoso-opensource-7:7.2.12-r17.1-g466615d-ubuntu]

This Docker image is using the following version of Virtuoso:

Virtuoso Open Source Edition (Column Store) (multi threaded)
Version 7.2.12-dev.3238-pthreads as of Dec 15 2023 (e49c0644f)
Compiled for Linux (x86_64-ubuntu_bionic-linux-gnu)
Copyright (C) 1998-2023 OpenLink Software

[HughWilliams]

we are looking into this ...