<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=""><br class=""><div><blockquote type="cite" class=""><div class="">On Jan 4, 2017, at 9:19 PM, David Sweeris <<a href="mailto:davesweeris@mac.com" class="">davesweeris@mac.com</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><meta http-equiv="content-type" content="text/html; charset=utf-8" class=""><div dir="auto" class=""><div class=""><br class=""></div><div class="">On Jan 4, 2017, at 20:48, Douglas Gregor via swift-evolution <<a href="mailto:swift-evolution@swift.org" class="">swift-evolution@swift.org</a>> wrote:<br class=""><br class=""></div><blockquote type="cite" class="">Yeah. I'm less sure about the other enhancements to existentials fitting into Swift 4, e.g., the creation of existentials for protocols with associated types. Although important, it's a big feature that will take a bunch of design and implementation time, and I'm leery of accepting something that we might not actually be able to achieve.</blockquote><br class=""><div class="">If it's a feature we know we want, it seems that nailing the syntax down, even if we <i class="">know</i> there isn't time to actually fully implement it in 4.0, would be beneficial simply to prevent it from being a source-breaking change in 4.1.</div></div></div></blockquote><br class=""></div><div>Well, there is an opportunity cost to designing something that you know won’t get implemented. That said, I won’t try to actually stop anyone from discussing such a much-needed feature; I just might not participate much.</div><div><br class=""></div><div><span class="Apple-tab-span" style="white-space:pre"> </span>- Doug</div><div><br class=""></div><br class=""></body></html>