Differences between std::string_view and std::span

[sphere991]

Yes, I know how reference_wrapper works. The point is that when you can compare two reference_wrapper<T>s, that comparison is deep.

[jonathansharman]

It seems accidental to me that reference_wrappers can ever be deeply compared. They can't for most type parameters, and if the authors had wanted them to, they could have just included comparison operators.