Question on: visit_expressions_mut

[cisaacson]

When I run visit_expressions_mut it works very well. However, I have no way to get to an alias expr, such as:

SELECT a.x, b.y AS myby, myfn(c.z) AS myfncall {
FROM t1
...

I pass the projection to visit_expressions_mut and I see the CompoundIdentifier and the Function expressions, but the alias rename does not come through. It seems like this is excluded, even though ExprWithAlias has a derive for VisitorMut. Is this intentional or a bug?