<div>Jordan Rose says in the comment on SR-4499 that Dmitri no longer works on Swift. Who owns that part of code now?</div><div><br></div><div>Also, who is able to answer my original questions from this thread?</div><div><br></div><div>--Pavol</div><div><br><div class="gmail_quote"><div>On Wed, 5 Apr 2017 at 18:56, Pavol Vaskovic <<a href="mailto:pali@pali.sk">pali@pali.sk</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">On Wednesday, 5 April 2017 at 16:04, rintaro ishizaki wrote:<br class="gmail_msg">
> Just FYI<br class="gmail_msg">
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> Implementation of Type Erasers<br class="gmail_msg">
> <a href="https://lists.swift.org/pipermail/swift-dev/Week-of-Mon-20160905/002852.html" rel="noreferrer" class="gmail_msg" target="_blank">https://lists.swift.org/pipermail/swift-dev/Week-of-Mon-20160905/002852.html</a><br class="gmail_msg">
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Thanks for that link!<br class="gmail_msg">
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This looks like a followup to Chris’s question, so I’m pinging Dmitri to chime in on this.<br class="gmail_msg">
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Bug report: <a href="https://bugs.swift.org/browse/SR-4499" rel="noreferrer" class="gmail_msg" target="_blank">https://bugs.swift.org/browse/SR-4499</a><br class="gmail_msg">
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For a reproducer, see the benchmark for `run_SuffixAnySequence` - that is utterly dominated by wending elements from the underlying sequence using generic witness table. There is no specialization occurring at all. As I’ve reasoned in my original e-mail, this is understandable - semantics of _AnyIteratorBox used in AnyIterator’s `next` method require virtual dispatch.<br class="gmail_msg">
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Closure based approach to type erasure should’t have such a semantic barrier for optimization - the limit would probably just be currently conservative optimization?<br class="gmail_msg">
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Best regards<br class="gmail_msg">
Pavol Vaskovic<br class="gmail_msg">
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