VB.Net introduces Conversion Operators. In some cases when passing an IQueryable as second query source inside a subquery. Presently, this results in a NotSupportedException because the conversion operator is represented as a UnaryExpression. To solve this, the conversion expression should probably simply be stripped out of the expression tree during the processing.
Example 1: This pattern occurs when using "OrderBy" in a subquery in VB.Net
The cxception occurs because of the cast to IEnumerable<customer>. This gets somewhere transformed to a Convert().