Hi, I don't know maybe it's the known bug, but I encountered it in my project. If it is in roadmap or somewhere else, excuse me for bothering... Unfortunately my investigations stuck somewhere inside -resolve-clause function, because I can't find where actually error happens. In attached test four first tests passing well, but four last ones failing. That shows that multiple clauses inside not clause are not working (but Datalog syntax supports it like I know). And more important thing is that using collection inside not clause makes whole clause looks ignored. Several commits ago last test returned more strange result like #{[nil]} ... So, I hope this helps.