LWG-3320 span::cbegin/cend methods produce different results than std::[ranges::]cbegin/cend

[StephanTLavavej]

LWG-3320 span::cbegin/cend methods produce different results than std::[ranges::]cbegin/cend

[miscco]

I Starter this, however now I am unsure whether we would want to remove the conversion operator entirely so that span_iterator<int> is not convertible to span_iterator<const int>

[StephanTLavavej]

I believe that the conversion operator needs to be removed. After this LWG issue resolution, the container requirements for the relationship between iterator and const_iterator don't apply (as const_iterator is gone), and there is no specified relationship between span<int>::iterator and span<const int>::iterator. (A user can still convert span<int> to span<const int> and then call begin().)

[miscco]

Thats what I thought too, but I wanted to get some confirmation before I push that change.

I will try to get a similar PR for libc++ to remove the corresponding tests and in the meanwhile disable the tests here