Array should be a NeverValueField type about subspace HOT 2 CLOSED

This is more tricky than I thought, because the NeverValueField requires that the field type be trivially constructible. This is required in order for Option to be constexpr at all.

The field in Array is T data_[N]; which is not trivially constructible, and is not a pointer as I wrote above silly me.

What I could do is defer it to the first element of the array if T is NeverValueField. That would require adding some more complexity to the never_value_field APIs to expose the field that is never-value, in order to reuse it from Array.

from subspace.

I'm not sure it's worth having X<T> be NeverValueField and X<U> not be, changing the layout of Option like that would be hard to understand from a user perspective. So making the NeverValueField conditional is probably not what I want to do, so Array can't be NeverValueField.

from subspace.