[Retric]

And further this all assumes they used int vs. long. It can be “wrong” in that it only works for arrays of under 2^63 elements without that ever being a possibility.

Production code is often filled with edge case bugs that simply never come up. Works for 100x the expected use case is generally good enough if you’re approaching the limits where 2^31 is a potential issue then you are also approaching the case where 2^32 definitely will be.