[swift-evolution] [Draft] Change IteratorType post-nil guarantee

Brent Royal-Gordon brent at architechies.com
Fri Mar 18 22:16:25 CDT 2016

> Current – post-nil unspecified
> – Responsibility of the caller, needs to be aware of the API contract and needs to track a bool and branch when relying on post-nil.
> – Standard library currently has 3 occurrences of this being necessary.

I got curious and decided to try to locate these. I found two:


(Interestingly the Zip one is defensive programming: ZipGenerator.next() is ensuring it doesn't incorrectly call its child generators' next() methods even if is itself called too many times.)

What was the third? I must have missed it.

Brent Royal-Gordon

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