> On 2 Sep 2025, at 14:14, Jan Schultke <janschultke_at_[hidden]> wrote:
>
> You seem to be confusing some mostly unrelated concepts.
>
>>> 1. C does not allow _BitInt(1); should C++ to make generic programming
>>> more comfortable?
>>
>> The ring ℤ/2ℤ of integers modulo 2, also a field, is isomorphic to the Boolean ring 𝔹 having exclusive or as addition and logical conjunction as multiplication.
>>
>> If bool 1+1 is defined to 0, then it is already in C++.
>
> Whether there is some other C++ thing that works mathematically the
> same doesn't say anything about whether _BitInt(1) is valid or should
> be valid. The issue is regarding a specific type.

It could have been defined to be the same as bool.

>> However, in GCC and Clang, bool 1+1 = 1, and I could not see what the standard specifies.
>
> Any nonzero integer is true when converted to bool, so "bool(true +
> true)" is essentially "1 + 1 != 0". bool gets promoted to int before
> any operation.

Apparently, there is no operator+ for bool. I did:
bool a = 1, b = 1, c = a + b;