t1.c0 IS TRUE is evaluated FALSE at the second SELECT, but the first SELECT still fetch rows with the same expression in the WHERE clause.

CREATE TABLE t1 (c0, c1);
INSERT INTO t1(c0) VALUES (2);
CREATE TABLE t2 (c0);
CREATE INDEX i0 ON t2 (c0) WHERE c0;
CREATE TABLE t3 (c0);
INSERT INTO t3 VALUES (1);
SELECT "-------------";
SELECT * FROM t2 RIGHT OUTER JOIN t3 ON t3.c0 LEFT OUTER JOIN t1 ON t2.c0 WHERE t1.c0;
-- |1|2|
SELECT (t1.c0 IS TRUE) FROM t2 RIGHT OUTER JOIN t3 ON t3.c0 LEFT OUTER JOIN t1 ON t2.c0;
-- 0

Environment:

Version: 3.39.0

Commit ID: 3f45007d

OS: Ubuntu 20.04

Configuration Options: ./configure --enable-all

Compiler: gcc-9

Client: CLI