<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="">Like I mentioned, it is necessary to use optional, but it can not be nil. Consider the following example where I have to use an optional in order to break retention cycle:<div class=""><br class=""></div><blockquote style="margin: 0 0 0 40px; border: none; padding: 0px;" class=""><div class=""><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo;" class=""><div style="margin: 0px; line-height: normal;" class=""><div style="margin: 0px; line-height: normal;" class=""><span style="font-variant-ligatures: no-common-ligatures; color: #0433ff" class="">protocol</span><span style="font-variant-ligatures: no-common-ligatures" class=""> Container : </span><span style="font-variant-ligatures: no-common-ligatures; color: #0433ff" class="">class</span><span style="font-variant-ligatures: no-common-ligatures" class=""> {</span></div></div></div></div><div class=""><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo;" class=""><div style="margin: 0px; line-height: normal;" class=""><div style="margin: 0px; line-height: normal;" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""> </span><span style="font-variant-ligatures: no-common-ligatures; color: #0433ff" class="">var</span><span style="font-variant-ligatures: no-common-ligatures" class=""> component: </span><span style="font-variant-ligatures: no-common-ligatures; color: #3495af" class="">Component</span><span style="font-variant-ligatures: no-common-ligatures" class=""> { </span><span style="font-variant-ligatures: no-common-ligatures; color: #0433ff" class="">get</span><span style="font-variant-ligatures: no-common-ligatures" class=""> }</span></div></div></div></div><div class=""><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo;" class=""><div style="margin: 0px; line-height: normal;" class=""><div style="margin: 0px; line-height: normal;" class=""><span style="font-variant-ligatures: no-common-ligatures" class="">}</span></div></div></div></div><div class=""><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo;" class=""><div style="margin: 0px; line-height: normal;" class=""><div style="margin: 0px; line-height: normal; min-height: 13px;" class=""><br class=""></div></div></div></div><div class=""><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo;" class=""><div style="margin: 0px; line-height: normal;" class=""><div style="margin: 0px; line-height: normal;" class=""><span style="font-variant-ligatures: no-common-ligatures; color: #0433ff" class="">class</span><span style="font-variant-ligatures: no-common-ligatures" class=""> ConcreteContainer : </span><span style="font-variant-ligatures: no-common-ligatures; color: #3495af" class="">Container</span><span style="font-variant-ligatures: no-common-ligatures" class=""> {</span></div></div></div></div><div class=""><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo;" class=""><div style="margin: 0px; line-height: normal;" class=""><div style="margin: 0px; line-height: normal;" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""> </span><span style="font-variant-ligatures: no-common-ligatures; color: #0433ff" class="">var</span><span style="font-variant-ligatures: no-common-ligatures" class=""> component: </span><span style="font-variant-ligatures: no-common-ligatures; color: #3495af" class="">Component</span><span style="font-variant-ligatures: no-common-ligatures" class="">! = </span><span style="font-variant-ligatures: no-common-ligatures; color: #0433ff" class="">nil</span></div></div></div></div><div class=""><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo;" class=""><div style="margin: 0px; line-height: normal;" class=""><div style="margin: 0px; line-height: normal;" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""> </span><span style="font-variant-ligatures: no-common-ligatures; color: #0433ff" class="">init</span><span style="font-variant-ligatures: no-common-ligatures" class="">() {</span></div></div></div></div><div class=""><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo;" class=""><div style="margin: 0px; line-height: normal;" class=""><div style="margin: 0px; line-height: normal;" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""> </span><span style="font-variant-ligatures: no-common-ligatures; color: #3495af" class="">component</span><span style="font-variant-ligatures: no-common-ligatures" class=""> = </span><span style="font-variant-ligatures: no-common-ligatures; color: #3495af" class="">Component</span><span style="font-variant-ligatures: no-common-ligatures" class="">(container: </span><span style="font-variant-ligatures: no-common-ligatures; color: #0433ff" class="">self</span><span style="font-variant-ligatures: no-common-ligatures" class="">)</span></div></div></div></div><div class=""><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo;" class=""><div style="margin: 0px; line-height: normal;" class=""><div style="margin: 0px; line-height: normal;" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""> }</span></div></div></div></div><div class=""><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo;" class=""><div style="margin: 0px; line-height: normal;" class=""><div style="margin: 0px; line-height: normal;" class=""><span style="font-variant-ligatures: no-common-ligatures" class="">}</span></div></div></div></div><div class=""><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo;" class=""><div style="margin: 0px; line-height: normal;" class=""><div style="margin: 0px; line-height: normal; min-height: 13px;" class=""><br class=""></div></div></div></div><div class=""><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo;" class=""><div style="margin: 0px; line-height: normal;" class=""><div style="margin: 0px; line-height: normal;" class=""><span style="font-variant-ligatures: no-common-ligatures; color: #0433ff" class="">class</span><span style="font-variant-ligatures: no-common-ligatures" class=""> Component {</span></div></div></div></div><div class=""><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo;" class=""><div style="margin: 0px; line-height: normal;" class=""><div style="margin: 0px; line-height: normal;" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""> </span><span style="font-variant-ligatures: no-common-ligatures; color: #0433ff" class="">unowned</span><span style="font-variant-ligatures: no-common-ligatures" class=""> </span><span style="font-variant-ligatures: no-common-ligatures; color: #0433ff" class="">let</span><span style="font-variant-ligatures: no-common-ligatures" class=""> container: </span><span style="font-variant-ligatures: no-common-ligatures; color: #3495af" class="">Container</span></div></div></div></div><div class=""><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo;" class=""><div style="margin: 0px; line-height: normal;" class=""><div style="margin: 0px; line-height: normal;" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""> </span><span style="font-variant-ligatures: no-common-ligatures; color: #0433ff" class="">init</span><span style="font-variant-ligatures: no-common-ligatures" class="">(container: </span><span style="font-variant-ligatures: no-common-ligatures; color: #3495af" class="">Container</span><span style="font-variant-ligatures: no-common-ligatures" class="">) {</span></div></div></div></div><div class=""><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo;" class=""><div style="margin: 0px; line-height: normal;" class=""><div style="margin: 0px; line-height: normal;" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""> </span><span style="font-variant-ligatures: no-common-ligatures; color: #0433ff" class="">self</span><span style="font-variant-ligatures: no-common-ligatures" class="">.</span><span style="font-variant-ligatures: no-common-ligatures; color: #3495af" class="">container</span><span style="font-variant-ligatures: no-common-ligatures" class=""> = container</span></div></div></div></div><div class=""><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo;" class=""><div style="margin: 0px; line-height: normal;" class=""><div style="margin: 0px; line-height: normal;" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""> }</span></div></div></div></div><div class=""><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo;" class=""><div style="margin: 0px; line-height: normal;" class=""><div style="margin: 0px; line-height: normal;" class=""><span style="font-variant-ligatures: no-common-ligatures" class="">}</span></div></div></div></div><div class=""><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo;" class=""><div style="margin: 0px; line-height: normal;" class=""><div class=""><span style="font-variant-ligatures: no-common-ligatures" class=""><br class=""></span></div></div></div></div><div class=""><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo;" class=""><div style="margin: 0px; line-height: normal;" class=""><div class=""><span style="font-variant-ligatures: no-common-ligatures" class=""><div style="margin: 0px; line-height: normal;" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""><b class="">Playground execution failed: error: scratchpad.playground:5:7: error: type 'ConcreteContainer' does not conform to protocol 'Container'</b></span></div></span></div></div></div></div><div class=""><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo;" class=""><div style="margin: 0px; line-height: normal;" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""><div style="margin: 0px; line-height: normal;" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""><b class="">class ConcreteContainer : Container {</b></span></div></span></div></div></div><div class=""><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo;" class=""><div style="margin: 0px; line-height: normal;" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""><div style="margin: 0px; line-height: normal;" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""><b class=""> ^</b></span></div></span></div></div></div><div class=""><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo;" class=""><div style="margin: 0px; line-height: normal;" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""><div style="margin: 0px; line-height: normal; min-height: 13px;" class=""><br class=""></div></span></div></div></div><div class=""><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo;" class=""><div style="margin: 0px; line-height: normal;" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""><div style="margin: 0px; line-height: normal;" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""><b class="">scratchpad.playground:2:9: note: protocol requires property 'component' with type 'Component'; do you want to add a stub?</b></span></div></span></div></div></div><div class=""><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo;" class=""><div style="margin: 0px; line-height: normal;" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""><div style="margin: 0px; line-height: normal;" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""><b class=""> var component: Component { get }</b></span></div></span></div></div></div><div class=""><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo;" class=""><div style="margin: 0px; line-height: normal;" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""><div style="margin: 0px; line-height: normal;" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""><b class=""> ^</b></span></div></span></div></div></div><div class=""><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo;" class=""><div style="margin: 0px; line-height: normal;" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""><div style="margin: 0px; line-height: normal; min-height: 13px;" class=""><br class=""></div></span></div></div></div><div class=""><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo;" class=""><div style="margin: 0px; line-height: normal;" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""><div style="margin: 0px; line-height: normal;" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""><b class="">scratchpad.playground:6:9: note: candidate has non-matching type 'Component!'</b></span></div></span></div></div></div><div class=""><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo;" class=""><div style="margin: 0px; line-height: normal;" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""><div style="margin: 0px; line-height: normal;" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""><b class=""> var component: Component! = nil</b></span></div></span></div></div></div><div class=""><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo;" class=""><div style="margin: 0px; line-height: normal;" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""><div style="margin: 0px; line-height: normal;" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""><b class=""> ^</b></span></div></span></div></div></div></blockquote><div class=""><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo;" class=""><div style="margin: 0px; line-height: normal;" class=""><div style="margin: 0px; line-height: normal; min-height: 13px;" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""></span></div></div></div></div><div class=""><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo;" class=""><div style="margin: 0px; line-height: normal;" class=""><div style="margin: 0px; line-height: normal; min-height: 13px;" class=""><br class=""><span style="font-variant-ligatures: no-common-ligatures" class=""></span></div></div></div></div><div class=""><div class=""><span style="font-variant-ligatures: no-common-ligatures" class="">Cheers,</span></div><div class=""><span style="font-variant-ligatures: no-common-ligatures" class="">Anton</span></div><div class=""><br class=""></div><div class="">P.S. Declaring protocol as</div><div class=""><br class=""></div></div><blockquote style="margin: 0 0 0 40px; border: none; padding: 0px;" class=""><div class=""><div class=""><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo;" class=""><span style="font-variant-ligatures: no-common-ligatures; color: #0433ff" class="">protocol</span><span style="font-variant-ligatures: no-common-ligatures" class=""> Container : </span><span style="font-variant-ligatures: no-common-ligatures; color: #0433ff" class="">class</span><span style="font-variant-ligatures: no-common-ligatures" class=""> {</span></div></div></div><div class=""><div class=""><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo;" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""> </span><span style="font-variant-ligatures: no-common-ligatures; color: #0433ff" class="">var</span><span style="font-variant-ligatures: no-common-ligatures" class=""> component: </span><span style="font-variant-ligatures: no-common-ligatures; color: #3495af" class="">Component</span><span style="font-variant-ligatures: no-common-ligatures" class="">! { </span><span style="font-variant-ligatures: no-common-ligatures; color: #0433ff" class="">get</span><span style="font-variant-ligatures: no-common-ligatures" class=""> }</span></div></div></div><div class=""><div class=""><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo;" class=""><span style="font-variant-ligatures: no-common-ligatures" class="">}</span></div></div></div></blockquote><div class=""><div class=""><span style="font-variant-ligatures: no-common-ligatures" class=""><br class=""></span></div><div class=""><span style="font-variant-ligatures: no-common-ligatures" class="">.. would also work of course, but my question is not about how to move forward, rather about whether such setup is deliberate.</span></div><div class=""><br class=""></div><div class=""><br class=""><div><blockquote type="cite" class=""><div class="">On 29 May 2017, at 08:20, Zhao Xin <<a href="mailto:owenzx@gmail.com" class="">owenzx@gmail.com</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><div dir="ltr" class=""><div class="gmail_default" style="font-family:georgia,serif">Why you have to use `<span style="font-size:12.800000190734863px;font-family:arial,sans-serif" class="">unwrapped optional` at the first place? If you have to use it, it means it could be nil. So it won't conform the protocol, which requires the `value` never nil.</span></div><div class="gmail_default" style="font-family:georgia,serif"><span style="font-family:Menlo;font-size:11px;font-variant-ligatures:no-common-ligatures;color:rgb(52,149,175)" class=""><br class=""></span></div><div class="gmail_default"><font face="georgia, serif" class="">Zhaoxin</font></div></div><div class="gmail_extra"><br class=""><div class="gmail_quote">On Mon, May 29, 2017 at 12:37 PM, Anton Bronnikov via swift-users <span dir="ltr" class=""><<a href="mailto:swift-users@swift.org" target="_blank" class="">swift-users@swift.org</a>></span> wrote:<br class=""><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div style="word-wrap:break-word" class="">Hi All,<div class=""><br class=""></div><div class="">If I have a protocol with a property requirement such as:</div><div class=""><br class=""></div><blockquote style="margin:0 0 0 40px;border:none;padding:0px" class=""><div class=""><div style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo;color:rgb(4,51,255)" class=""><span style="font-variant-ligatures:no-common-ligatures" class="">protocol</span><span style="font-variant-ligatures: no-common-ligatures;" class=""> Foo {</span></div></div><div class=""><div style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo" class=""><span style="font-variant-ligatures:no-common-ligatures" class=""> </span><span style="font-variant-ligatures:no-common-ligatures;color:#0433ff" class="">var</span><span style="font-variant-ligatures:no-common-ligatures" class=""> value: </span><span style="font-variant-ligatures:no-common-ligatures;color:#3495af" class="">Int</span><span style="font-variant-ligatures:no-common-ligatures" class=""> { </span><span style="font-variant-ligatures:no-common-ligatures;color:#0433ff" class="">get</span><span style="font-variant-ligatures:no-common-ligatures" class=""> }</span></div></div><div class=""><div style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo" class=""><span style="font-variant-ligatures:no-common-ligatures" class="">}</span></div></div></blockquote><div class=""><br class=""></div><div class="">.. and I need to conform to it using an implicitly unwrapped optional like:</div><div class=""><br class=""></div><blockquote style="margin:0 0 0 40px;border:none;padding:0px" class=""><div class=""><div style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo" class=""><span style="font-variant-ligatures:no-common-ligatures;color:#0433ff" class="">struct</span><span style="font-variant-ligatures:no-common-ligatures" class=""> Bar : </span><span style="font-variant-ligatures:no-common-ligatures;color:#3495af" class="">Foo</span><span style="font-variant-ligatures:no-common-ligatures" class=""> {</span></div></div><div class=""><div style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo" class=""><span style="font-variant-ligatures:no-common-ligatures" class=""> </span><span style="font-variant-ligatures:no-common-ligatures;color:#0433ff" class="">let</span><span style="font-variant-ligatures:no-common-ligatures" class=""> value: </span><span style="font-variant-ligatures:no-common-ligatures;color:#3495af" class="">Int</span><span style="font-variant-ligatures:no-common-ligatures" class="">! = </span><span style="font-variant-ligatures:no-common-ligatures;color:#0433ff" class="">nil</span></div></div><div class=""><div style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo" class=""><span style="font-variant-ligatures:no-common-ligatures" class="">}</span></div></div></blockquote><div class=""><br class=""></div><div class="">.. then the compiler fails with an error:</div><div class=""><br class=""></div><blockquote style="margin:0 0 0 40px;border:none;padding:0px" class=""><div class=""><div style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo" class=""><span style="font-variant-ligatures:no-common-ligatures" class=""><b class="">Playground execution failed: error: scratchpad.playground:5:8: error: type 'Bar' does not conform to protocol 'Foo'</b></span></div></div><div class=""><div style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo" class=""><span style="font-variant-ligatures:no-common-ligatures" class=""><b class="">struct Bar : Foo {</b></span></div></div><div class=""><div style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo" class=""><span style="font-variant-ligatures:no-common-ligatures" class=""><b class=""> ^</b></span></div></div><div class=""><div style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo;min-height:13px" class=""><br class=""></div></div><div class=""><div style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo" class=""><span style="font-variant-ligatures:no-common-ligatures" class=""><b class="">scratchpad.playground:2:9: note: protocol requires property 'value' with type 'Int'; do you want to add a stub?</b></span></div></div><div class=""><div style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo" class=""><span style="font-variant-ligatures:no-common-ligatures" class=""><b class=""> var value: Int { get }</b></span></div></div><div class=""><div style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo" class=""><span style="font-variant-ligatures:no-common-ligatures" class=""><b class=""> ^</b></span></div></div><div class=""><div style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo;min-height:13px" class=""><br class=""></div></div><div class=""><div style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo" class=""><span style="font-variant-ligatures:no-common-ligatures" class=""><b class="">scratchpad.playground:6:9: note: candidate has non-matching type 'Int!'</b></span></div></div><div class=""><div style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo" class=""><span style="font-variant-ligatures:no-common-ligatures" class=""><b class=""> let value: Int! = nil</b></span></div></div><div class=""><div style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo" class=""><span style="font-variant-ligatures:no-common-ligatures" class=""><b class=""> ^</b></span></div></div></blockquote><div class=""><div style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo;min-height:13px" class=""><span style="font-variant-ligatures:no-common-ligatures" class=""><b class=""></b></span></div></div><div class="">Technically, I understand why the error, and currently work around it with a cumbersome:</div><div class=""><br class=""></div><blockquote style="margin:0 0 0 40px;border:none;padding:0px" class=""><div class=""><div style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo" class=""><span style="font-variant-ligatures:no-common-ligatures;color:#0433ff" class="">struct</span><span style="font-variant-ligatures:no-common-ligatures" class=""> Bar : </span><span style="font-variant-ligatures:no-common-ligatures;color:#3495af" class="">Foo</span><span style="font-variant-ligatures:no-common-ligatures" class=""> {</span></div></div><div class=""><div style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo" class=""><span style="font-variant-ligatures:no-common-ligatures" class=""> </span><span style="font-variant-ligatures:no-common-ligatures;color:#0433ff" class="">var</span><span style="font-variant-ligatures:no-common-ligatures" class=""> value: </span><span style="font-variant-ligatures:no-common-ligatures;color:#3495af" class="">Int</span><span style="font-variant-ligatures:no-common-ligatures" class=""> { </span><span style="font-variant-ligatures:no-common-ligatures;color:#0433ff" class="">return</span><span style="font-variant-ligatures:no-common-ligatures" class=""> </span><span style="font-variant-ligatures:no-common-ligatures;color:#3495af" class="">_value</span><span style="font-variant-ligatures:no-common-ligatures" class="">! }</span></div></div><div class=""><div style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo" class=""><span style="font-variant-ligatures:no-common-ligatures" class=""> </span><span style="font-variant-ligatures:no-common-ligatures;color:#0433ff" class="">let</span><span style="font-variant-ligatures:no-common-ligatures" class=""> _value: </span><span style="font-variant-ligatures:no-common-ligatures;color:#3495af" class="">Int</span><span style="font-variant-ligatures:no-common-ligatures" class="">? = </span><span style="font-variant-ligatures:no-common-ligatures;color:#0433ff" class="">nil</span></div></div><div class=""><div style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo" class=""><span style="font-variant-ligatures:no-common-ligatures" class="">}</span></div></div></blockquote><div class=""><br class=""></div><div class="">However, I keep wondering - would it not be making sense to accept implicitly unwrapped optionals as a conformance to be base-type requirements? It sort of works just like that in all other parts of the language.</div><div class=""><br class=""></div><div class="">Or in other words, is this by design, or should I probably create an issue for this?</div><div class=""><br class=""></div><div class="">Thank you.</div><div class="">Cheers,</div><div class="">Anton</div><div class=""><br class=""></div><div class="">P.S. The example is oversimplified for the sake of clarity, in practice the property just has to be an optional - implicitly unwrapped or not - because it’s a part of the composite that holds unowning reference to its container object.</div><div class=""><br class=""></div></div><br class="">______________________________<wbr class="">_________________<br class="">
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