Bug in ^^

[lithium iodate]

On Tuesday, 17 September 2019 at 19:36:14 UTC, Vladimir Panteleev 
wrote:
> I'm not so sure that's the actual distinction.
>
> The error messages do not mention undefined behavior.

Formally, operations with unsigned integers can never overflow in 
C and you can therefore not warn about overflow. Since the 
warning can then only occur for signed integers (as observed), 
any such warning directly implies undefined behavior as per the C 
standard.