This member is added by an implicit conversion from RemoveFieldNames to
any2stringadd[RemoveFieldNames] performed by method any2stringadd in scala.Predef.
This member is added by an implicit conversion from RemoveFieldNames to
StringFormat[RemoveFieldNames] performed by method StringFormat in scala.Predef.
Convert unreferenced StructNodes to single columns or ProductNodes (which is needed for aggregation functions and at the top level).