Dmitry

> I am not sure why pg tests fails... I'll take a look at it today.

Blocked by #2382.

> To reference a field from the input document you must prefix it with the $ symbol. Otherwise it will just set the field to the type of the expression...

Oh, I see. ```js test> db.values.find({}, {'v': {'$type': 'v'}}) [ { _id: 'null', v: 'string' }, { _id: 'regex', v: 'string' }, { _id: 'double-smallest', v: 'string' }, { _id:...