Revert most of PR #168 i.e of the commit f436c3029850c138e54a0de055d61db45130409e. It added bunch of checks all over the place, but most of them shouldn't be needed: If they are true, our internal state is already broken. In other words, those checks are hiding real bugs and making debugging harder. Hopefully the underlying bugs are already fixed in some of previous commits addressing some fuzzing issues, like these: * d775b5103ee130edbd808e21d1da6ca75f76a558 * c6942ef03ed46a67bd9b3af8ce1eefd781622777