Thanks for mentioning testing - while thinking about whether it would be practical to test this, I realized that I was confused by reading LWG-3464, which said:

On a 32-bit platform files larger than 2GB can overflow the counter

This might not apply to our implementation. We always use long long:

There's no practical way to exceed 2⁶³ - 1, and thus no practical way to test this.

However, we are affected by #388 - I'm not sure if that's relevant here. I would guess not, since this is directly incrementing an integer, but I'm not certain.

So, I wonder whether we need to make any changes here at all. That said, I believe that the PR clearly doesn't harm correctness, and I believe that it won't harm performance either (the function can be inlined, and the branch is trivially predictable).

Thanks for implementing this LWG issue and making the Status Chart happier (when it's updated next week)! 😸