[OT] The Usual Arithmetic Confusions

[Steven Schveighoffer]

On 2/4/22 5:22 PM, Paul Backus wrote:
> On Friday, 4 February 2022 at 22:11:10 UTC, Steven Schveighoffer wrote:
>> I don't think anyone is arguing that the result of the operation 
>> should be truncated to a byte, even if assigned to an int.
> 
> And yet, that's exactly what happens if you use `int` and `long`:
> 
>      int a = int.max;
>      long b = a + 1;
>      writeln(b > 0); // false
> 
> I think there are reasonable arguments to be made on both sides, but 
> having both behaviors in the same language is a bit of a mess, don't you 
> think?

Yes, I would prefer for the compiler to determine if the overflow is 
needed, and generate appropriate instructions based on that.

The reason this doesn't come up often for int -> long is because a) you 
aren't usually converting an int-only operation to a long, and b) 
overflow of an int is rare.

-Steve