> On Jan 27, 2017, at 10:39 AM, tuuranton--- via swift-users > <swift-users@swift.org> wrote: > > Yes, but why? > > What's the rationale for this? > > What would be so bad about allowing overriding a non-failable initializer > with a failable initializer?
If the non-failable initializer witnesses a non-failable protocol requirement, and the subclass overrides it, what should be the runtime behavior if the subclass initializer returns nil? The caller won’t expect it, since the caller is calling a non-failable initializer. For similar reasons, you cannot override a method that returns a non-optional value with a method returning an optional value. Slava > > 27. Jan 2017 18:59 by saa...@saagarjha.com <mailto:saa...@saagarjha.com>: > > You can’t override a designated initializer with one that is failable. The > second one is defining a new initializer that is failable, instead of > overriding the one from its superclass. > > Saagar Jha > > On Jan 27, 2017, at 8:45 AM, tuuranton--- via swift-users > <swift-users@swift.org <mailto:swift-users@swift.org>> wrote: > > See the comments. Why is one allowed but the other one isn't and what's the > rationale for this? > > > class Vehicle { > let name: String > init(name: String) { > self.name = name > } > } > > > class Car: Vehicle { > //Why is this not allowed? > override init?(name: String) { > super.init(name: name) > } > > //But this is allowed? > init?(name: String, ignore: String) { > super.init(name: name) > } > } > > > > _______________________________________________ > swift-users mailing list > swift-users@swift.org <mailto:swift-users@swift.org> > https://lists.swift.org/mailman/listinfo/swift-users > <https://lists.swift.org/mailman/listinfo/swift-users> > > _______________________________________________ > swift-users mailing list > swift-users@swift.org > https://lists.swift.org/mailman/listinfo/swift-users
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