<html><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class="">Ah yes, my eye skipped that alternative for some reason! Sorry.<div class=""><br class=""></div><div class="">I’d be concerned that avoiding a default is a fix for a compatibility problem, not a language design decision. If we look back in 5 years and say “why do we need to keep writing nonexhaustive everywhere?”, we’ll have to say “there were compatibility problems with Swift 4-to-5”. That reeks of a language I just want to walk away from. Yuk.</div><div class=""><br class=""></div><div class="">In this case, either way, we’ll need to do some work. So why not let the migrator migrate this code correctly to “exhaustive”, which is the current behaviour? I think a decision where either way we break source compatibility should be done in the interest of language design, not in the short term interest of avoiding confusion.</div><div class=""><br class=""></div><div class="">But that’s just my 2c.</div><div class=""><br class=""></div><div class="">Thanks,</div><div class=""><br class=""></div><div class="">Rod</div><div class=""><br class=""></div><div class=""> </div><div class=""><div class=""><div class=""><div><br class=""><blockquote type="cite" class=""><div class="">On 6 Sep 2017, at 10:36 am, Jordan Rose <<a href="mailto:jordan_rose@apple.com" class="">jordan_rose@apple.com</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><meta http-equiv="Content-Type" content="text/html; charset=utf-8" class=""><div style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class=""><div class="">It's in the "Alternatives Considered" section. :-) That was my desired design when we started, but feedback convinced me that the break from Swift 4 mode would be too drastic. The same valid code would have a different meaning whether you were writing Swift 4 or Swift 5.</div><div class=""><br class=""></div><div class="">Jordan</div><br class=""><div class=""><br class=""><blockquote type="cite" class=""><div class="">On Sep 5, 2017, at 17:30, Rod Brown <<a href="mailto:rodney.brown6@icloud.com" class="">rodney.brown6@icloud.com</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><meta http-equiv="Content-Type" content="text/html; charset=utf-8" class=""><div style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class="">Hi Jordan,<div class=""><br class=""></div><div class="">I’m not sure how much bearing on this my comment will have.<div class=""><br class=""></div><div class="">Have you considered having only “exhaustive” as a keyword, and make the default non-exhaustive? It seems that “exhaustive" would be the rarer case, as it promises a lot more about compatibility (much like there is no such thing as “non-final”). Also, non exhaustive seems a massive mouthful despite it probably being the correct term.</div><div class=""><br class=""></div><div class="">- Rod</div><div class=""><div class=""><br class=""><blockquote type="cite" class=""><div class="">On 6 Sep 2017, at 10:19 am, Jordan Rose <<a href="mailto:jordan_rose@apple.com" class="">jordan_rose@apple.com</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><meta http-equiv="Content-Type" content="text/html; charset=utf-8" class=""><div style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class=""><div class="">I've taken everyone's feedback into consideration and written this up as a proposal: <a href="https://github.com/jrose-apple/swift-evolution/blob/non-exhaustive-enums/proposals/nnnn-non-exhaustive-enums.md" class="">https://github.com/jrose-apple/swift-evolution/blob/non-exhaustive-enums/proposals/nnnn-non-exhaustive-enums.md</a>. The next step is working on an implementation, but if people have further pre-review comments I'd be happy to hear them.</div><div class=""><br class=""></div><div class="">Jordan</div></div></div></blockquote></div></div></div></div></div></blockquote></div><br class=""></div></div></blockquote></div><br class=""></div></div></div></body></html>