<html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head><body dir="auto"><div></div><div>How would that work for a subclass, if all properties of a class need to be initialized before the parent's initializer is called?</div><div><br></div><div>-Andrew</div><div><br>On Mar 11, 2017, at 8:46 AM, Derrick Ho via swift-evolution <<a href="mailto:swift-evolution@swift.org">swift-evolution@swift.org</a>> wrote:<br><br></div><blockquote type="cite"><div>Seems like it should work. Maybe it is a bug that should be reported to SR.<br><br>Does this error occur for non-failable initializers?<br><div class="gmail_quote"><div dir="ltr">On Sat, Mar 11, 2017 at 12:33 AM David Sweeris via swift-evolution <<a href="mailto:swift-evolution@swift.org">swift-evolution@swift.org</a>> wrote:<br></div><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="gmail_msg">Is this a feature or a bug?<blockquote style="margin:0 0 0 40px;border:none;padding:0px" class="gmail_msg"><div class="gmail_msg"><div style="margin:0px;line-height:normal" class="gmail_msg"><div style="margin:0px;line-height:normal;font-family:Menlo" class="gmail_msg"><span style="font-variant-ligatures:no-common-ligatures;color:#ba2da2" class="gmail_msg">class</span><span style="font-variant-ligatures:no-common-ligatures" class="gmail_msg"> Foo {</span></div><div style="margin:0px;line-height:normal;font-family:Menlo" class="gmail_msg"><span style="font-variant-ligatures:no-common-ligatures" class="gmail_msg"> </span><span style="font-variant-ligatures:no-common-ligatures;color:#ba2da2" class="gmail_msg">let</span><span style="font-variant-ligatures:no-common-ligatures" class="gmail_msg"> bar: </span><span style="font-variant-ligatures:no-common-ligatures;color:#703daa" class="gmail_msg">Int</span></div><div style="margin:0px;line-height:normal;font-family:Menlo" class="gmail_msg"><span style="font-variant-ligatures:no-common-ligatures" class="gmail_msg"> </span><span style="font-variant-ligatures:no-common-ligatures;color:#ba2da2" class="gmail_msg">init</span><span style="font-variant-ligatures:no-common-ligatures" class="gmail_msg">?(someConditionBasedOnInputData: </span><span style="font-variant-ligatures:no-common-ligatures;color:#703daa" class="gmail_msg">Bool</span><span style="font-variant-ligatures:no-common-ligatures" class="gmail_msg">) {</span></div><div style="margin:0px;line-height:normal;font-family:Menlo" class="gmail_msg"><span style="font-variant-ligatures:no-common-ligatures" class="gmail_msg"> </span><span style="font-variant-ligatures:no-common-ligatures;color:#ba2da2" class="gmail_msg">var</span><span style="font-variant-ligatures:no-common-ligatures" class="gmail_msg"> localBar: </span><span style="font-variant-ligatures:no-common-ligatures;color:#703daa" class="gmail_msg">Int</span><span style="font-variant-ligatures:no-common-ligatures" class="gmail_msg"> = </span><span style="font-variant-ligatures:no-common-ligatures;color:#272ad8" class="gmail_msg">0</span></div><div style="margin:0px;line-height:normal;font-family:Menlo" class="gmail_msg"><span style="font-variant-ligatures:no-common-ligatures" class="gmail_msg"> </span><span style="font-variant-ligatures:no-common-ligatures;color:#ba2da2" class="gmail_msg">defer</span><span style="font-variant-ligatures:no-common-ligatures" class="gmail_msg"> {</span></div><div style="margin:0px;line-height:normal;font-family:Menlo;color:rgb(0,132,0)" class="gmail_msg"><span style="font-variant-ligatures:no-common-ligatures;color:#000000" class="gmail_msg"> bar = localBar </span><span style="font-variant-ligatures:no-common-ligatures" class="gmail_msg">//Cannot assign to property: 'bar' is a 'let' constant</span></div><div style="margin:0px;line-height:normal;font-family:Menlo" class="gmail_msg"><span style="font-variant-ligatures:no-common-ligatures" class="gmail_msg"> }</span></div><div style="margin:0px;line-height:normal;font-family:Menlo" class="gmail_msg"><span style="font-variant-ligatures:no-common-ligatures" class="gmail_msg"> </span><span style="font-variant-ligatures:no-common-ligatures;color:#ba2da2" class="gmail_msg">if</span><span style="font-variant-ligatures:no-common-ligatures" class="gmail_msg"> someConditionBasedOnInputData {</span></div><div style="margin:0px;line-height:normal;font-family:Menlo" class="gmail_msg"><span style="font-variant-ligatures:no-common-ligatures" class="gmail_msg"> </span><span style="font-variant-ligatures:no-common-ligatures;color:#ba2da2" class="gmail_msg">return</span><span style="font-variant-ligatures:no-common-ligatures" class="gmail_msg"> </span><span style="font-variant-ligatures:no-common-ligatures;color:#ba2da2" class="gmail_msg">nil</span></div><div style="margin:0px;line-height:normal;font-family:Menlo" class="gmail_msg"><span style="font-variant-ligatures:no-common-ligatures" class="gmail_msg"> }</span></div><div style="margin:0px;line-height:normal;font-family:Menlo" class="gmail_msg"><span style="font-variant-ligatures:no-common-ligatures" class="gmail_msg"> }</span></div><div style="margin:0px;line-height:normal;font-family:Menlo" class="gmail_msg"><span style="font-variant-ligatures:no-common-ligatures" class="gmail_msg">}</span></div></div></div></blockquote>It’d be handy to be able to do the assignment upfront in a defer block in cases where there’s both a bunch of validation to do on the input data, and no harm from assigning the interim values to the final values when you’re about to return nil anyway.<div class="gmail_msg"><br class="gmail_msg"></div><div class="gmail_msg">- Dave Sweeris</div></div>_______________________________________________<br class="gmail_msg">
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