Reports alias expressions that duplicate names of columns in tables and might be redundant.

Example (PostgreSQL):

CREATE TABLE foo(a INT, b INT);

SELECT * FROM foo foo(a, b);
SELECT * FROM foo foo(a);
SELECT * FROM foo foo(x);
SELECT * FROM foo foo(x, y);

The first two aliases use the same column names as in the foo table. They are considered redundant because they column names are identical.