Once again, why do we need the size?
Shall we check the size?
Via static_assert?
During runtime?

>>> That makes it possible to use a random pointer with `std::get`.
Yes, is this bad?

pointer can be used in constant expression:
https://gcc.godbolt.org/z/hq8rbE4cj

On Tue, Mar 1, 2022 at 5:01 PM Jason McKesson via Std-Proposals <
std-proposals_at_[hidden]> wrote:

> On Mon, Feb 28, 2022 at 2:04 PM Nikolay Mihaylov via Std-Proposals
> <std-proposals_at_[hidden]> wrote:
> >
> > no need to deduce the size, I would do it like this:
> >
> > #include <cstdint>
> >
> > template<std::size_t IX, typename T>
> > auto const &get(T const *a){
> > return a[IX];
> > }
> >
> > int main(){
> > int x[100] = { 0, 1, 2, 3 };
> >
> > return get<3>(x);
> > }
>
> That makes it possible to use a random pointer with `std::get`. The
> point of this feature is that you can provide a compile-time index for
> accessing a C-style array (and compile-time bounds checking). By
> deducing the size, you prevent people from just passing a pointer,
> which is *good* because that's not what the feature is for.
>
> If you have a compile-time index, and a compile-time sized array,
> there is zero reason to allow out-of-bounds accesses. And if you have
> a runtime-sized array... you shouldn't be using `std::get` for it. The
> `std::get` interface isn't for runtime-sized things.
> --
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