On Sep 26, 2013, at 4:19 , Daniel Marjamäki <[email protected]>
wrote:
> Hi Jordan!
>
>> Even though this actually does something ("++x == ++x"), it's not
>> well-defined anyway (specifically, either one could go first), so I'd still
>> like to catch this as a copy-paste error. What do you think?
>
> Yes this is true now as we are only checking comparison operators. However:
>
> 1. When we extend it to && and || operators we must be more careful about
> this. We can of course add logic later that avoids increment only if the top
> operator is && or ||.
>
> 2. I think it would be interesting to add new diagnostics about undefined
> execution order. Then we will warn about ("++x == ++x") with a stronger
> warning message that complains about undefined behaviour.
We actually do have that already:
<stdin>:3:2: warning: multiple unsequenced modifications to 'x' [-Wunsequenced]
++x == ++x;
^ ~~
So maybe it's okay.
Jordan_______________________________________________
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