SE-0283: Tuples conform to Equatable, Comparable, and Hashable

[Joe_Groff]

@allevato

So the key distinction (and the thing that keeps us from being boxed in later with arbitrary tuple conformances) is the fact that this is a conformance being implicitly applied to all tuples (with all Hashable elements), as opposed to one where the author is explicitly asking for the conformance by writing some syntax (which could, in the future, allow elements to witness requirements of the same name)?

Yeah, in principle, if we later allowed conformances for specific tuple types (or we allowed a conformance to explicitly request conditional behavior for sets of types with one of the mechanisms Doug describes here), then any labeled members could conceivably be eligible to become witnesses at that point.