I find NaN is mostly unhelpful on balance. It can help avoid crashes, but you get garbage results and it’s often hard to trace back to the underlying culprit. N

I find NaN is mostly unhelpful on balance. It can help avoid crashes, but you get garbage results and it’s often hard to trace back to the underlying culprit. NaN means kicking the can down the road and failing as late as possible, but failing early means much easier debugging. Something like a NaN (for arbitrary operations, not just floats) that could also give you a full backtrace would be very interesting -- a bit like Java’s nested exceptions.