I am sorry. I don't actually care whether you call this a bug, an enhancement or an improvement. I just wanted to point out that unlike the original query, which does not make sense if you regard the where clause as an implicit and therefor inner join, the query using `is not null` would work perfectly fine if an inner join was generated. So the argument against the validity of the original where clause does not hold in case of this modified where clause, because the path p.child is not null.