<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="">It’s an interesting idea, but with the workaround you’ve found I wonder if it might make more sense to just have Unowned<T> and Weak<T> in the standard library? I’ve already defined these myself to work with a few awkward cases and to allow entries in collections to be weakly referenced.</div><div class=""><br class=""></div><div class="">I mean it’d be nice to have keyword support too; I wonder if could be made more flexible, e.g- let us also write things like:</div><div class=""><br class=""></div><div class=""><font face="Monaco" class=""><span class="Apple-tab-span" style="white-space:pre"> </span>let foo:[weak AnyObject] = …</font></div><div class=""><br class=""></div><div class="">Externally this would appear as if the array were of type AnyObject?, but internally the array would have an actual type of Weak<AnyObject> or whatever. I dunno, just thinking out loud, point being that maybe this isn’t enum specific, even though enum is an important use-case, i.e- a keyword or global function could make this easier to do throughout the language.</div><br class=""><div><blockquote type="cite" class=""><div class="">On 3 May 2016, at 16:07, Marc Prud'hommeaux 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=""><meta http-equiv="Content-Type" content="text/html charset=us-ascii" class=""><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div class=""><br class=""></div><div class="">The following code currently has a retain cycle and memory leak:</div><div class=""><br class=""></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; color: #0433ff" class="">enum</span><span style="font-variant-ligatures: no-common-ligatures" class=""> ParentChild {</span></div><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="">case</span><span style="font-variant-ligatures: no-common-ligatures" class=""> SonOf(</span><span style="font-variant-ligatures: no-common-ligatures; color: #3495af" class="">Parent</span><span style="font-variant-ligatures: no-common-ligatures" class="">)</span></div><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="">case</span><span style="font-variant-ligatures: no-common-ligatures" class=""> DaughterOf(</span><span style="font-variant-ligatures: no-common-ligatures; color: #3495af" class="">Parent</span><span style="font-variant-ligatures: no-common-ligatures" class="">)</span></div><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 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=""></span><br class=""></div><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="">class</span><span style="font-variant-ligatures: no-common-ligatures" class=""> Parent {</span></div><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="">lazy</span><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=""> son: </span><span style="font-variant-ligatures: no-common-ligatures; color: #3495af" class="">Child</span><span style="font-variant-ligatures: no-common-ligatures" class=""> = </span><span style="font-variant-ligatures: no-common-ligatures; color: #3495af" class="">Child</span><span style="font-variant-ligatures: no-common-ligatures" class="">(parentChild: .</span><span style="font-variant-ligatures: no-common-ligatures; color: #3495af" class="">SonOf</span><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></div><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="">lazy</span><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=""> daughter: </span><span style="font-variant-ligatures: no-common-ligatures; color: #3495af" class="">Child</span><span style="font-variant-ligatures: no-common-ligatures" class=""> = </span><span style="font-variant-ligatures: no-common-ligatures; color: #3495af" class="">Child</span><span style="font-variant-ligatures: no-common-ligatures" class="">(parentChild: .</span><span style="font-variant-ligatures: no-common-ligatures; color: #3495af" class="">DaughterOf</span><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></div><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo; color: rgb(180, 38, 26);" class=""><span style="" class=""> </span><span style="font-variant-ligatures: no-common-ligatures; color: #0433ff" class="">deinit</span><span style="" class=""> { </span><span style="font-variant-ligatures: no-common-ligatures; color: #3495af" class="">print</span><span style="" class="">(</span><span style="font-variant-ligatures: no-common-ligatures" class="">"deinit Parent"</span><span style="" class="">) }</span></div><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 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=""></span><br class=""></div><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="">class</span><span style="font-variant-ligatures: no-common-ligatures" class=""> Child {</span></div><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=""> parentChild: </span><span style="font-variant-ligatures: no-common-ligatures; color: #3495af" class="">ParentChild</span></div><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="">init</span><span style="font-variant-ligatures: no-common-ligatures" class="">(parentChild: </span><span style="font-variant-ligatures: no-common-ligatures; color: #3495af" class="">ParentChild</span><span style="font-variant-ligatures: no-common-ligatures" class="">) {</span></div><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="">self</span><span style="font-variant-ligatures: no-common-ligatures" class="">.</span><span style="font-variant-ligatures: no-common-ligatures; color: #3495af" class="">parentChild</span><span style="font-variant-ligatures: no-common-ligatures" class=""> = parentChild</span></div><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 style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo; color: rgb(180, 38, 26);" class=""><span style="" class=""> </span><span style="font-variant-ligatures: no-common-ligatures; color: #0433ff" class="">deinit</span><span style="" class=""> { </span><span style="font-variant-ligatures: no-common-ligatures; color: #3495af" class="">print</span><span style="" class="">(</span><span style="font-variant-ligatures: no-common-ligatures" class="">"deinit Child"</span><span style="" class="">) }</span></div><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 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=""></span><br class=""></div><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=""></span><br class=""></div><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="">do</span><span style="font-variant-ligatures: no-common-ligatures" class=""> {</span></div><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=""> parent = </span><span style="font-variant-ligatures: no-common-ligatures; color: #3495af" class="">Parent</span><span style="font-variant-ligatures: no-common-ligatures" class="">()</span></div><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo;" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""> parent.</span><span style="font-variant-ligatures: no-common-ligatures; color: #3495af" class="">son</span></div><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo;" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""> parent.</span><span style="font-variant-ligatures: no-common-ligatures; color: #3495af" class="">daughter</span></div><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 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=""><br class=""></span></div><div class="">Child.parentChild cannot be declared unowned because ParentChild is a value type. I propose adding the ability to declare the reference storage class for an enum's associated value, like so:</div><div class=""><br class=""></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; color: #0433ff" class="">enum</span><span style="font-variant-ligatures: no-common-ligatures" class=""> ParentChild {</span></div><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="">case</span><span style="font-variant-ligatures: no-common-ligatures" class=""> SonOf(unowned Parent)</span></div><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="">case</span><span style="font-variant-ligatures: no-common-ligatures" class=""> DaughterOf(unowned Parent)</span></div><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 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="">The only current alternative is to have some intermediate reference type that itself holds the reference, akin to the old "Box" type that we used to use to work around enum limitations. E.g., this is our current cumbersome work-around:</span></div><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=""><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo; color: rgb(0, 143, 0);" class=""><span style="font-variant-ligatures: no-common-ligatures" class="">/// An unowned reference to a value, which is useful for maintaining parent-child relations through value types like enums</span></div><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="">public</span><span style="font-variant-ligatures: no-common-ligatures" class=""> </span><span style="font-variant-ligatures: no-common-ligatures; color: #0433ff" class="">struct</span><span style="font-variant-ligatures: no-common-ligatures" class=""> UnownedRef<T: AnyObject></span><span style="font-variant-ligatures: no-common-ligatures" class=""> {</span></div><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo; color: rgb(4, 51, 255);" class=""><span style="" class=""> </span><span style="font-variant-ligatures: no-common-ligatures" class="">public</span><span style="" class=""> </span><span style="font-variant-ligatures: no-common-ligatures" class="">unowned</span><span style="" class=""> </span><span style="font-variant-ligatures: no-common-ligatures" class="">let</span><span style="" class=""> value: </span><span style="font-variant-ligatures: no-common-ligatures; color: #3495af" class="">T</span></div><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: rgb(4, 51, 255);" class="">public</span><span style="font-variant-ligatures: no-common-ligatures;" class=""> </span><span style="font-variant-ligatures: no-common-ligatures; color: rgb(4, 51, 255);" class="">init</span><span style="font-variant-ligatures: no-common-ligatures;" class="">(</span><span style="font-variant-ligatures: no-common-ligatures; color: rgb(4, 51, 255);" class="">_</span><span style="font-variant-ligatures: no-common-ligatures;" class=""> value: </span><span style="font-variant-ligatures: no-common-ligatures; color: rgb(52, 149, 175);" class="">T</span><span style="font-variant-ligatures: no-common-ligatures;" class="">) { </span><span style="font-variant-ligatures: no-common-ligatures; color: rgb(4, 51, 255);" class="">self</span><span style="font-variant-ligatures: no-common-ligatures;" class="">.</span><span style="font-variant-ligatures: no-common-ligatures; color: rgb(52, 149, 175);" class="">value</span><span style="font-variant-ligatures: no-common-ligatures;" class=""> = value }</span></div><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 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=""></span><br class=""></div><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="">enum</span><span style="font-variant-ligatures: no-common-ligatures" class=""> ParentChild {</span></div><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo; color: rgb(52, 149, 175);" class=""><span style="" class=""> </span><span style="font-variant-ligatures: no-common-ligatures; color: #0433ff" class="">case</span><span style="" class=""> SonOf(</span><span style="font-variant-ligatures: no-common-ligatures" class="">UnownedRef</span><span style="" class=""><</span><span style="font-variant-ligatures: no-common-ligatures" class="">Parent</span><span style="" class="">>)</span></div><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="">case</span><span style="font-variant-ligatures: no-common-ligatures" class=""> DaughterOf(</span><span style="font-variant-ligatures: no-common-ligatures; color: #3495af" class="">UnownedRef</span><span style="font-variant-ligatures: no-common-ligatures" class=""><</span><span style="font-variant-ligatures: no-common-ligatures; color: #3495af" class="">Parent</span><span style="font-variant-ligatures: no-common-ligatures" class="">>)</span></div><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 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=""></span><br class=""></div><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=""></span><br class=""></div><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="">class</span><span style="font-variant-ligatures: no-common-ligatures" class=""> Parent {</span></div><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="">lazy</span><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=""> son: </span><span style="font-variant-ligatures: no-common-ligatures; color: #3495af" class="">Child</span><span style="font-variant-ligatures: no-common-ligatures" class=""> = </span><span style="font-variant-ligatures: no-common-ligatures; color: #3495af" class="">Child</span><span style="font-variant-ligatures: no-common-ligatures" class="">(parentChild: .</span><span style="font-variant-ligatures: no-common-ligatures; color: #3495af" class="">SonOf</span><span style="font-variant-ligatures: no-common-ligatures" class="">(</span><span style="font-variant-ligatures: no-common-ligatures; color: #3495af" class="">UnownedRef</span><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></div><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="">lazy</span><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=""> daughter: </span><span style="font-variant-ligatures: no-common-ligatures; color: #3495af" class="">Child</span><span style="font-variant-ligatures: no-common-ligatures" class=""> = </span><span style="font-variant-ligatures: no-common-ligatures; color: #3495af" class="">Child</span><span style="font-variant-ligatures: no-common-ligatures" class="">(parentChild: .</span><span style="font-variant-ligatures: no-common-ligatures; color: #3495af" class="">DaughterOf</span><span style="font-variant-ligatures: no-common-ligatures" class="">(</span><span style="font-variant-ligatures: no-common-ligatures; color: #3495af" class="">UnownedRef</span><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></div><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo; color: rgb(180, 38, 26);" class=""><span style="" class=""> </span><span style="font-variant-ligatures: no-common-ligatures; color: #0433ff" class="">deinit</span><span style="" class=""> { </span><span style="font-variant-ligatures: no-common-ligatures; color: #3495af" class="">print</span><span style="" class="">(</span><span style="font-variant-ligatures: no-common-ligatures" class="">"deinit Foo"</span><span style="" class="">) }</span></div><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 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=""></span><br class=""></div><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="">class</span><span style="font-variant-ligatures: no-common-ligatures" class=""> Child {</span></div><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=""> parentChild: </span><span style="font-variant-ligatures: no-common-ligatures; color: #3495af" class="">ParentChild</span></div><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="">init</span><span style="font-variant-ligatures: no-common-ligatures" class="">(parentChild: </span><span style="font-variant-ligatures: no-common-ligatures; color: #3495af" class="">ParentChild</span><span style="font-variant-ligatures: no-common-ligatures" class="">) {</span></div><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="">self</span><span style="font-variant-ligatures: no-common-ligatures" class="">.</span><span style="font-variant-ligatures: no-common-ligatures; color: #3495af" class="">parentChild</span><span style="font-variant-ligatures: no-common-ligatures" class=""> = parentChild</span></div><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 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=""></span><br class=""></div><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo; color: rgb(180, 38, 26);" class=""><span style="" class=""> </span><span style="font-variant-ligatures: no-common-ligatures; color: #0433ff" class="">deinit</span><span style="" class=""> { </span><span style="font-variant-ligatures: no-common-ligatures; color: #3495af" class="">print</span><span style="" class="">(</span><span style="font-variant-ligatures: no-common-ligatures" class="">"deinit Child"</span><span style="" class="">) }</span></div><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 class=""><span style="font-variant-ligatures: no-common-ligatures" class=""><br class=""></span></div></span></div><div class=""><span style="font-variant-ligatures: no-common-ligatures" class="">The storage type of an enum would, of course, be limited to reference types, and when the storage class is weak, it would require that the stored type be Optional, just like when declaring a weak variable.</span></div><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="">What do people think?</span></div><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=""><span class="Apple-tab-span" style="white-space:pre"> </span>-Marc</span></div><div class=""><br class=""></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>