It is not always safe to implicitly rewrite a `tuple` function
call to a literal. Even when the tuple has more then one element
e.g.
`SELECT (tuple(1, 2, 3) AS x).1` is not equivalent to
`SELECT ((1, 2, 3) AS x).1`, the latter is interpreted as
`SELECT tuple((1, 2, 3) AS x).1`.
