Exists is currently converted to PathDefault which is NOT translated into an interval. The goals of the task are to

• allow PathDefault to be translated into an interval
• allow simplifications between the intervals of a non-traversed path (e.g. Get "a" Id) and a traversed path (e.g. Get "a" Traverse Id) in the case the non-traversed path encodes an existence of an array, or just an existence in general.

Queries to test with:

{a:{$ne:null, $exists:true}}

{a:{$gt:1, $exists:true}}

{a:{$eq:null, $exists:true{}}