[renox]

This part is very bad, 99% of the time if you overflow a 64 bit variable it is because you did the wrong computation, not because you need BigInts..

[saghm]

I'm not sure I can remember any time I messed up by using a 64-bit int rather than a BigInt. I can remember plenty of times I should have either just used saturating add/subtract or was trying to compute something that was basically nonsense regardless of what integer width or operation I was doing