Incorrect join order for CROSS JOIN LATERAL

[sim1984]

Firebird 5.0.3.1622

The optimizer selects the wrong join order when using CROSS JOIN LATERAL with complex table expressions.

SELECT
  T.NAME
FROM
  RDB$RELATIONS R
  CROSS JOIN LATERAL (
    SELECT R.RDB$RELATION_NAME AS NAME FROM RDB$DATABASE
    UNION ALL
    SELECT R.RDB$OWNER_NAME AS NAME FROM RDB$DATABASE
  ) T

The cursor identified in the UPDATE or DELETE statement is not positioned on a row.
no current record for fetch operation.
-----------------------------------------------------------------------------------
SQLCODE: -508
SQLSTATE: 22000
GDSCODE: 335544348

Explain plan:

Select Expression
    -> Nested Loop Join (inner)
        -> Union
            -> Table "RDB$DATABASE" as "T RDB$DATABASE" Full Scan
            -> Table "RDB$DATABASE" as "T RDB$DATABASE" Full Scan
        -> Table "RDB$RELATIONS" as "R" Full Scan

Obviously, the derived table T depends on the outer stream and cannot be the first in the join.

Using LEFT JOIN LATERAL fixes the error.

SELECT
  T.NAME
FROM
  RDB$RELATIONS R
  LEFT JOIN LATERAL (
    SELECT R.RDB$RELATION_NAME AS NAME FROM RDB$DATABASE
    UNION ALL
    SELECT R.RDB$OWNER_NAME AS NAME FROM RDB$DATABASE
  ) T ON TRUE

Explain plan:

Select Expression
    -> Nested Loop Join (outer)
        -> Table "RDB$RELATIONS" as "R" Full Scan
        -> Filter
            -> Union
                -> Table "RDB$DATABASE" as "T RDB$DATABASE" Full Scan
                -> Table "RDB$DATABASE" as "T RDB$DATABASE" Full Scan