On Fri, Mar 31, 2023 at 12:50 PM Sebastian Wittmeier via Std-Proposals
<std-proposals_at_[hidden]> wrote:
>
> Could you explain, when the promotion would be detrimental?
>
> E.g.: unsigned overflow is defined behaviour (in comparison to signed overflow), but would it be useful, when you cannot predict the bitwidth?


Take the following:

    extern void Func(uint32_t);
    extern void Func(int64_t);

    void Monkey(uint32_t const arg)
    {
        Func(arg + 5);
    }

The overload called here is different depending on whether int is
32-Bit or 64-Bit.

Also let's say we allow it to roll over:

    uint32_t value = 5;

    auto monkey = value + 3;

    for ( ; ; monkey += 1024u*128u)
    {
        // Do something
    }

We get undefined behaviour here if 'monkey' is a signed 64-Bit integer
and we let it overflow.