[swift-evolution] [Draft][Proposal] Formalized Ordering

[Pyry Jahkola]

Pyry Jahkola wrote:

>> or even to ask whether
>> someSequence.contains(.nan).  IMO that's not really acceptable.
> 
> Not correct. Algorithms like contains(_:) or firstIndex(of:) would use the == operator which is part of the protocol and thus wouldn't call <=> on FloatingPoint types which override the default implementation.

Oops, spoke too soon. Well, I think it's easy enough to require people to write numbers.contains(where: { $0.isNaN }) in this use case.

— Pyry