Bug: ScalarSubqueryToJoin fails with "No field named __always_true" when CTE inside correlated scalar subquery

[niebayes]

Reproduction:

DataFusion CLI v54.1.0
> CREATE TABLE metrics (host VARCHAR, bytes_sent DOUBLE, ts BIGINT) AS VALUES
    ('a', 100.0, 1),
    ('b', 200.0, 2),
    ('a', 300.0, 3),
    ('b', 400.0, 4);

0 row(s) fetched. 
Elapsed 0.011 seconds.

> SELECT m.host, m.bytes_sent
FROM metrics m
WHERE m.bytes_sent > (
    WITH avg_per_host AS (
        SELECT avg(bytes_sent) AS avg_bytes
        FROM metrics
        WHERE host = m.host
    )
    SELECT avg_bytes FROM avg_per_host
);
Optimizer rule 'scalar_subquery_to_join' failed
caused by
Schema error: No field named __always_true. Valid fields are avg_per_host.avg_bytes.

[duongcongtoai]

take