<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><blockquote type="cite" class=""><div class=""><div style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: 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;" class="">Why two, and why empty? UIViewController would supply its own empty default implementation.</div></div></blockquote><div>The before/after pair: viewWillAppear would need a call to "subclassViewWillAppear" (which would be empty in the declaring class, and need a subsubclassViewWillAppear where it is overriden…) — and the same with viewDidAppear.</div><div>For properties, Swift has a special mechanism that saves us from the need to come up with names for new extension points (willSet/didSet), but there is no equivalent for regular methods.</div><div>I'm not propagating the use of long inheritance chains, but a language imho shouldn't try to educate its users by making it hard to use a paradigm it claims to support.</div><div><br class=""></div><blockquote type="cite" class=""><div class=""><div style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: 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;" class="">There's no law saying you *can't* call super if you absolutely must build a two-level hierarchy below UIViewController (though there are ways around that—the main one being to avoid inheritance hierarchies). I just don't want to create a world where you're always expected to call super everywhere, which is what would happen if we always warn when you don't call super.</div></div></blockquote></div>I'm skeptical on adding more restrictions as well, so I guess I'd be fine with "you have to call super" as opt-in. After all, it is less restrictive than declaring everything final (which is a tiny bit safer, but much more limiting).<div class="">But afaics, no one has empirical data on how often each case (must call super, must not call super, do as you like) happens...</div></body></html>