This is the second part of the fix for the performance regression seen in #1250. In #1217, for correctness reasons, we're now traversing all the conditional groups. This means that we're now in O(n^2). But, in practice, many of those groups are === between each others. So we only need to recurse through one of the instances to know if it's going to break.
This makes the first example go from not terminating to being instant. The second one going from not terminating to taking ~1s. We can also make it instant by tweaking the printing phase, but that's for another PR.
Christopher Chedeau