[saagarjha]

I mean, if you're doing two's complement arithmetic as the example relies on then it's certainly useful. If you want any other behavior, then it is not. (Rust's differing behavior between different optimization levels IMO makes it basically impossible to use usefully, FWIW.)

[mehrdadn]

How likely is that "if", though? How often when you see signed multiplication in code do you find people are actually paying attention to the negative results and planning around 2's complement behavior? I know there are occasions in which people do this, but it's so incredibly rare compared to when they multiply two numbers. And on the rare occasions when the bit patterns actually matter to them and they're paying attention, it's not like they have no way to solve the problem in C++.

[saagarjha]

If it wasn't clear, I'm saying that making the behavior defined is nice, but personally I think defining it to wrap is not the best way it could have been done. IMO a consistent trap would have been nicer.