<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="">You might know already, but you can write f2 { n } instead of f2(c: { n }).<div class=""><br class=""></div><div class="">I checked my code and found that this isn't a problem over here. Inertia is the only thing that guides my opinion here, I think that I could be swayed one way or the other rather easily.<br class=""><div class="">
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<br class=""><div><blockquote type="cite" class=""><div class="">Le 25 août 2016 à 23:58:28, Fabian Ehrentraud via swift-evolution <<a href="mailto:swift-evolution@swift.org" class="">swift-evolution@swift.org</a>> a écrit :</div><br class="Apple-interchange-newline"><div class=""><div class="">The implemented change for closures being @noescape by default is awesome, but an important case was missed. When the closure is stored into a local variable, there currently is no way to make that variable non-escaping.<br class=""><br class=""><br class="">class A {<br class=""><span class="Apple-tab-span" style="white-space:pre"> </span><br class=""><span class="Apple-tab-span" style="white-space:pre"> </span>let n: Int = 1<br class=""><span class="Apple-tab-span" style="white-space:pre"> </span>var cp: (() -> Int)?<br class=""><span class="Apple-tab-span" style="white-space:pre"> </span><br class=""><span class="Apple-tab-span" style="white-space:pre"> </span>func f1() {<br class=""><span class="Apple-tab-span" style="white-space:pre"> </span><span class="Apple-tab-span" style="white-space:pre"> </span>// when directly constructing a new closure in the function call, the compiler knows it will be non-escaping, and no explicit `self` is needed in the closure...<br class=""><span class="Apple-tab-span" style="white-space:pre"> </span><span class="Apple-tab-span" style="white-space:pre"> </span>f2(c: { n })<br class=""><span class="Apple-tab-span" style="white-space:pre"> </span><span class="Apple-tab-span" style="white-space:pre"> </span><br class=""><span class="Apple-tab-span" style="white-space:pre"> </span><span class="Apple-tab-span" style="white-space:pre"> </span>// ... but when storing the closure in an intermediate variable, it is not assumed as non-escaping, and explicit `self` is needed, and also we cannot prevent that it can be stored in some escaping way<br class=""><span class="Apple-tab-span" style="white-space:pre"> </span><span class="Apple-tab-span" style="white-space:pre"> </span>let c: () -> Int = {<br class=""><span class="Apple-tab-span" style="white-space:pre"> </span><span class="Apple-tab-span" style="white-space:pre"> </span><span class="Apple-tab-span" style="white-space:pre"> </span>// the closure variable would need to know if it is escaping or not, as this has impact on whether the user needs to think about problems with strong capture semantics<br class=""><span class="Apple-tab-span" style="white-space:pre"> </span><span class="Apple-tab-span" style="white-space:pre"> </span><span class="Apple-tab-span" style="white-space:pre"> </span>return self.n<br class=""><span class="Apple-tab-span" style="white-space:pre"> </span><span class="Apple-tab-span" style="white-space:pre"> </span>}<br class=""><span class="Apple-tab-span" style="white-space:pre"> </span><span class="Apple-tab-span" style="white-space:pre"> </span>f2(c: c)<br class=""><span class="Apple-tab-span" style="white-space:pre"> </span><span class="Apple-tab-span" style="white-space:pre"> </span><br class=""><span class="Apple-tab-span" style="white-space:pre"> </span><span class="Apple-tab-span" style="white-space:pre"> </span>// this should actually not be allowed, unless the closure c is marked as @escaping<br class=""><span class="Apple-tab-span" style="white-space:pre"> </span><span class="Apple-tab-span" style="white-space:pre"> </span>cp = c<br class=""><span class="Apple-tab-span" style="white-space:pre"> </span>}<br class=""><span class="Apple-tab-span" style="white-space:pre"> </span><br class=""><span class="Apple-tab-span" style="white-space:pre"> </span>func f2(c: () -> Int) -> Int {<br class=""><span class="Apple-tab-span" style="white-space:pre"> </span><span class="Apple-tab-span" style="white-space:pre"> </span>return c()<br class=""><span class="Apple-tab-span" style="white-space:pre"> </span>}<br class=""><span class="Apple-tab-span" style="white-space:pre"> </span><br class="">}<br class=""><br class=""><br class="">Is this rather a bug in the implementation of SE-0103, or a new feature request?<br class=""><br class=""><br class="">best,<br class="">Fabian<br class="">_______________________________________________<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></div></blockquote></div><br class=""></div></body></html>