I want to raise my personal concern around the proposed solution to Issue2157.

I do not believe that std::array<T, 0> {{}}; should be required to be valid syntax. This prevents std::array<T, 0> from being implemented as an empty struct. It is also just logically inconsistent with an array that contains no elements. I believe this eliminates empty base class optimization and presents several other issues that I believe diverge from the 0 overhead principle. For this reason I think the solution ought to be reconsidered.