<html><head><meta http-equiv="Content-Type" content="text/html; charset=us-ascii"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class=""><br class=""><div><br class=""><blockquote type="cite" class=""><div class="">On Jan 2, 2018, at 11:29, Douglas Gregor via swift-dev <<a href="mailto:swift-dev@swift.org" class="">swift-dev@swift.org</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><div class="" style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;"><div class=""><blockquote type="cite" class="" style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; text-decoration: none;"><div class=""><div class=""><div class="" style="font-family: sans-serif;"><div class="" style="white-space: normal;"><p dir="auto" class="">Just to be clear, what is the current impact of leaving those<span class="Apple-converted-space"> </span><code bgcolor="#F7F7F7" class="" style="background-color: rgb(247, 247, 247); border-top-left-radius: 3px; border-top-right-radius: 3px; border-bottom-right-radius: 3px; border-bottom-left-radius: 3px; margin: 0px; padding: 0px 0.4em;">Codable</code><span class="Apple-converted-space"> </span>conformances conditional? Having casts like<span class="Apple-converted-space"> </span><code bgcolor="#F7F7F7" class="" style="background-color: rgb(247, 247, 247); border-top-left-radius: 3px; border-top-right-radius: 3px; border-bottom-right-radius: 3px; border-bottom-left-radius: 3px; margin: 0px; padding: 0px 0.4em;">[1,2,3] as? Codable</code><span class="Apple-converted-space"> </span>fail?<br class=""></p></div></div></div></div></blockquote><div style="caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none;" class="">Right. Those casts, which would have succeeded in Swift 4, will fail (with a runtime warning) in Swift 4.1.</div></div></div></div></blockquote><br class=""></div><div>Codable in particular doesn't have this problem because it has initializer requirements. Encodable on its own technically does, but nothing really works with Encodable on its own anyway because the whole system is optimized for round-tripping. If Codable is the only thing we we're worried about, it shouldn't stop us.</div><div><br class=""></div><div>Jordan</div><br class=""></body></html>