Multiple occurrences of query vars in pattern and aggregates

[zoren]

With this query:

(q '[:find (count ?e) .
     :with ?i
     :where [?e :r ?e ?i]]
   [[1 :r 1 10]
    [2 :r 1 11]])

I get 1 with Datomic but 2 in datascript. It appears the test for two occurrences of a query variable is tested too late.

[tonsky]

Looks like it. Related: #336

[refset]

I think this self-unification issue is related too: https://github.com/tonsky/datascript/issues/240