<html><head><meta http-equiv="Content-Type" content="text/html charset=us-ascii"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><br class=""><div><blockquote type="cite" class=""><div class="">On Dec 15, 2015, at 7:15 PM, Greg Parker <<a href="mailto:gparker@apple.com" class="">gparker@apple.com</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><span style="font-family: HelveticaNeue; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; float: none; display: inline !important;" class="">We could make it more difficult for unaware programmers to *write* the `[strong self]` version, at least. When a programmer writes just `metadata` in a closure, the compiler could continue to suggest using `self.metadata` and not suggest using `[strong self]`.</span></div></blockquote></div><br class=""><div class="">That's not (especially) the danger I'm worried about.</div><div class=""><br class=""></div><div class="">I'm worried about the case where I write `[strong self] in` and then years later I add the `evil(f)` to the bottom of the closure, because it turns out we need more code in there.</div><div class=""><br class=""></div><div class="">I'm also worried about the case where I write nonEvil(f) but at some later time the implementation of nonEvil(f) becomes evil.</div><div class=""><br class=""></div><div class="">I'm also worried about the case where nonEvil(f) is a call into closed-source UIKit and without any visibility to me, UIKit's implementation of nonEvil becomes evil between iOS10b3 and iOS10b4.</div><div class=""><br class=""></div><div class="">These things are "category 5" bugs waiting to happen, and they can't be competently addressed with a UI-level fix in Xcode.</div></body></html>