Strange casting rules

_Ported from CodePlex_

``` SQL
SELECT (CAST(e.EmployeeID AS byte) * CAST(3 AS byte)).GetType() AS MyType
FROM Employees e
```

The expression is evaluated as:

```
(CAST(CAST(e.EmployeeID AS BYTE) AS INT64) * 3).GetType()
```

Strange casting rules...
