ALTER TABLE ... RENAME ... doesn't handle pseudo-column LEVEL correctly

Detail name	Value
Changelog Number	9670
Type	Bug
Status	Resolved
Affected Versions	Exasol 6.1.0, Exasol 6.2.0, Exasol 7.0.alpha1
Fix Versions	Exasol 7.0.beta1, Exasol 6.2.7
Resolution Date	2020-05-20

Background

By default, pseudo-column LEVEL is not allowed as an ordinary column name in a table.

Example

Following statements throw exception. It is expected behavior.
Error: [42000] LEVEL not allowed as column name.

CREATE TABLE T1 (LEVEL INT);
ALTER TABLE T1 ADD COLUMN LEVEL INT; 

Problem

However next statement allows to change the name, which cause inconsistent state. In this case, exception is expected.

ALTER TABLE T1 RENAME COLUMN X TO LEVEL;