<html><head><meta http-equiv="Content-Type" content="text/html charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div class="">Hi Chris,</div><div class=""><br class=""></div><div class="">The topic has been heavily discussed last year, culminating into a massing proposal by Austin Zheng:</div><div class=""><br class=""></div><div class=""><a href="https://github.com/austinzheng/swift-evolution/blob/az-existentials/proposals/XXXX-enhanced-existentials.md#nested-typealias-existential" class="">https://github.com/austinzheng/swift-evolution/blob/az-existentials/proposals/XXXX-enhanced-existentials.md#nested-typealias-existential</a></div><div class=""><br class=""></div><div class="">The proposal was never merged and postponed for a future Swift release. This feature is very important for me so I reopened it earlier this month:</div><div class=""><br class=""></div><div class=""><a href="https://lists.swift.org/pipermail/swift-evolution/Week-of-Mon-20170102/029890.html" class="">https://lists.swift.org/pipermail/swift-evolution/Week-of-Mon-20170102/029890.html</a></div><div class=""><br class=""></div><div class="">Douglas Gregor replied to this thread saying that part of the proposal (superclass and protocol constraints) should be proposed and implemented for Swift 4, but that the remaining more generalised has little chance to make it in time for Swift 4.</div><div class=""><br class=""></div><div class="">In consequence, I started a new thread with the smaller feature of superclass and protocol constraints:</div><div class=""><br class=""></div><div class=""><a href="https://lists.swift.org/pipermail/swift-evolution/Week-of-Mon-20170123/031066.html" class="">https://lists.swift.org/pipermail/swift-evolution/Week-of-Mon-20170123/031066.html</a></div><div class=""><br class=""></div><div class="">Quite a few comments have already been made about the proposal so I’ll post a new draft soon. But please let me know if you have more comments!</div><div class=""><br class=""></div><div class="">David.</div><br class=""><div><blockquote type="cite" class=""><div class="">On 31 Jan 2017, at 11:07, Chris Eidhof via swift-evolution <<a href="mailto:swift-evolution@swift.org" class="">swift-evolution@swift.org</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><div dir="ltr" class="">Hi swift-evolution,<div class=""><br class=""></div><div class="">I was wondering if anything more detailed has been written about generalized existentials / type erasers. I noticed that AnyCollection only delegates a number of methods to its wrapped value, but often doesn't. For example, all the conditionally inherited items aren't being delegated (e.g. min()). This behavior was surprising to me (but makes sense once I thought about it longer).</div><div class=""><br class=""></div><div class="">How would this work with generalized existentials? Are generalized existentials in scope at all for Swift 4?<br clear="all" class=""><div class=""><br class=""></div>-- <br class=""><div class="gmail_signature" data-smartmail="gmail_signature">Chris Eidhof</div>
</div></div>
_______________________________________________<br class="">swift-evolution mailing list<br class=""><a href="mailto:swift-evolution@swift.org" class="">swift-evolution@swift.org</a><br class="">https://lists.swift.org/mailman/listinfo/swift-evolution<br class=""></div></blockquote></div><br class=""></body></html>