I think there’s something strange with popFirst. It doesn’t show up in the autocomplete in Xcode, but it compiles, and popLast doesn’t throw the same error. removeFirst doesn’t either, though it’s unsafe. Weird.
Jon > On Sep 13, 2017, at 9:47 PM, Zhao Xin via swift-users <swift-users@swift.org> > wrote: > > I begin to think it is related to how you `popFirst()` implemented. Check it > or post it here. > > Zhao Xin > > On Thu, Sep 14, 2017 at 9:36 AM, Roderick Mann <rm...@latencyzero.com > <mailto:rm...@latencyzero.com>> wrote: > Yeah, that's not it. I made the change you suggested, I get the same error. > > > On Sep 13, 2017, at 18:11 , Zhao Xin <owe...@gmail.com > > <mailto:owe...@gmail.com>> wrote: > > > > Change `self` to `ModelFetcher`. You are calling a class static property, > > not a class instance property. > > > > Zhao Xin > > > > On Thu, Sep 14, 2017 at 8:37 AM, Rick Mann via swift-users > > <swift-users@swift.org <mailto:swift-users@swift.org>> wrote: > > Moving to Swift 4, I'm running into an issue for which I can't seem to find > > an answer in google: > > > > "Cannot use mutating member on immutable value: 'self' is immutable" > > > > The code looks like: > > > > class > > ModelFetcher : NSObject, URLSessionDelegate > > { > > ... > > static let managerDispatchQueue = > > DispatchQueue(label: "Model Download Manager Queue") > > static var pendingFetchers = > > [ModelFetcher]() > > static var currentFetcher: ModelFetcher? > > > > class > > func > > startNextFetcher() > > { > > self.managerDispatchQueue.async > > { > > guard > > self.currentFetcher == nil, > > let mf = self.pendingFetchers.popFirst() > > ~~~~ ^ error: cannot > > use mutating member on immutable value: 'self' is immutable > > else > > { > > return > > } > > > > self.currentFetcher = mf > > mf.start() > > } > > } > > ... > > } > > > > This code compiled fine in Xcode 8, or in Xcode 9/Swift 3.2 as a monolithic > > app (the error shows up when this code is factored into a framework). Other > > mutating references to self seem to compile okay (e.g. "self.currentFetcher > > = nil" or "self.pendingFetchers.remove(at: idx)"). Not sure what's special > > about this one. > > > > > > -- > > Rick Mann > > rm...@latencyzero.com <mailto:rm...@latencyzero.com> > > > > > > _______________________________________________ > > 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> > > > > > -- > Rick Mann > rm...@latencyzero.com <mailto:rm...@latencyzero.com> > > > > _______________________________________________ > swift-users mailing list > swift-users@swift.org > https://lists.swift.org/mailman/listinfo/swift-users
_______________________________________________ swift-users mailing list swift-users@swift.org https://lists.swift.org/mailman/listinfo/swift-users
