There's a count variable for computing the total possible enumeration of a $or query.

This variable could overflow if the $or is large enough, e.g. a machine generated $or with 200 predicates. Each predicate has two possible enumerations. The size_t count would overflow with a value of 2^200.

While calculating the count, we can bail out early if the count reaches the limit for $or, which is 10 by default.