[swift-evolution] [Accepted] SE-0052: Change IteratorType post-nil guarantee

[Chris Lattner]

Proposal link: https://github.com/apple/swift-evolution/blob/master/proposals/0052-iterator-post-nil-guarantee.md

Hello Swift Community,

The review of SE-0052: "Change IteratorType post-nil guarantee" ran from April 28...May 3, 2016. The proposal is *accepted* for Swift 3.

The feedback on this proposal was generally positive from the community and core team.  The most significant concern was about performance: strengthening the requirement on IteratorType.next() could make some implementations of iterators slower.  On the other hand, it does make some clients faster (UTF8 decoding being one cited case that demonstrates a big win).  The core team believes that the improvements to performance in the most common use-cases will more than balance the reductions in performance for other cases.

Thank you to Patrick Pijnappel for proposing and implementing this!

-Chris
Review Manager