15 . All review feedback should be either on this forum thread or, if you would like to keep your feedback private, directly to the review. Escaping closure captures non-escaping parameter 'completion' (Swift 5) 1 Capturing closures within closures: Xcode throws error: Escaping closure captures non-escaping parameter1. Accessing an actor's isolated state from within a SwiftUI view. swift. onReceive (somePublisher) { self. 6. – ctietze. game = game } func fetchUser (uid: String) { User. Swift ui Escaping closure captures mutating 'self' parameter. Here, the performLater function accepts an escaping closure as its parameter. I understand that the line items. . Escaping closure captures mutating ‘self’ parameter. I use this boolean to show a view on a certain state of the view. {"payload":{"allShortcutsEnabled":false,"fileTree":{"proposals":{"items":[{"name":"0001-keywords-as-argument-labels. This file contains bidirectional Unicode text that may be interpreted or compiled differently than what. Escaping closure captures mutating 'self' parameter. That violates the rule. Escaping closure captures 'inout' parameter. MyView {value in MyContent() } How do I declare the view to have that?👉 StackOverflow： What's 'Escaping closure captures mutating 'self' parameter' and how to fix itところが、イニシャライザで実装しているようにStateの変更をトリガーにUITextViewのプロパティを変更したいと思っても、Escaping closure captures mutating 'self' parameterというエラーが出てコンパイルできません。The introducing of @escaping or @nonEscaping for optional closures should be easily accepted. ShareIn-out parameters are used to modify parameter values. This is where capture lists come in, which enable us to customize how a given closure captures any of the objects or values that it refers to. You cannot call this method: private static func getAndCacheAPIData <CodableClass: Any & Codable>(type:CodableClass. But if you make it @escaping, you get error: escaping closure captures mutating 'self' parameter. Learn more about TeamsIn Swift 1. As the error said, in the escaping closure, you're capturing and mutating self (actually self. In one of the views of my application I need to mutate some data. SwiftUI run method on view when Published view model member value changes. Non-Escaping Closures. async { self. That is, if the object keeps a reference to this closure, and this closure keeps a reference to the object, neither one of them can ever be deallocated. Last modified. answered Dec 22, 2015 at 15:23. 1. 6. Swift ui Escaping closure captures mutating 'self' parameter. ' can only be used as a generic constraint because it has Self or associated type. You can fix this by either removing @escaping, or you change the value types to reference types. Q&A for work. struct MyView: View { @State var current: Int = 0 var body: some View { Text (" (current)") . When creating a closure in mutating function of a struct capturing self is not possible: struct Foo { var bar: Bool mutating func createClosure() -> () -> Bool {. Here’s a quick shorthand: A non-escaping closure can refer to self implicitly How do I reference a mutable variable in a completion handler (so that I can access it's property's value at the time that the completion handler is eventually called, not when it is captured) while avoiding the "Escaping closure captures mutating 'self' parameter" error? I have a boolean called 'isMatched'. myThing = "thing" } but that would only change the value of the variable myself , and not affect anything outside of your function. longitude of the struct without having to use the wilderness part explicitly? Capturing an inout parameter, including self in a mutating method. The purpose of this would be to have a convenient way to create a Binding in DetailView that was called from a NavigationLink of a List. DispatchQueue. 2. state) { newState in // depending on newState your decision here presentationMode. image = $0 } // 雖然下面的語法沒有出現錯誤訊息，但依然沒用Escaping closure captures mutating 'self' parameter Hello, I am new to swift programming and I've been having this error "Escaping closure captures mutating. In the Core Audio Recorder example the AudioQueueInputCallback function is written as a variable binding outside the class Recorder. latitude and wilderness. Publisher, accessible via the $ prefix, which will publish any time the value changes. The first is to explicitly use the self keyword whenever we’re calling a method or accessing a property on the current object within such a closure. Hot Network Questions Space-ships and stations. " but we are using this inside the functionStack Overflow | The World’s Largest Online Community for DevelopersThis is due to a change in the default behaviour for parameters of function type. i. Using this. When I debug with breakpoints it shows Disposables. // escaping closure captures mutating `self` parameter . (where I use an explicit self. For a small application that I want to implement I’d like to stick with MVVM. Swift. [self] in is implicit, for. in the closure, but when using [unowned self], you can omit self. current. . So, after a function returns, a variable that is passed as &variable will have the modified value In most cases, Swift manages memory…2. md","path":"proposals/0001-keywords-as-argument. it just capture the copied value, but before the function returns it is not called. wrappedValue. The AppTwo works, and AppOne does not work with the next short error: Escaping closure captures mutating 'self' parameter The code: struct Response {} struct Request {} struct. init (initialValue. @autoclosure (escaping) is now written as @autoclosure @escaping. In this recent thread: An odd error: "Escaping closure captures mutating 'self'" - #10 by Jens, I, (well, actually @Jens), just found out that this code compiles: func test(_ callback: () -> Void) { // Compiles, no need for it to be @escaping let x = callback x() } It baffles me because I don't think we have non-escaping closure types (yet). The call to the some Function With Escaping Closure function in the example above is an error because it’s inside a mutating method, so self is mutable. , if they have closures, follow the default. When that escaping closure references self, or a strongly retained property, it will capture that reference strongly. Your function is asynchronous, so it exits immediately and cani is not modified. . An escaping closure can cause a strong reference cycle if you use self inside the closure. My issue is a bit more niche as I am working with an API that gives me a function that takes in an @escaping function (or so I think). increase() // may work } If you change model to reference type, i. For a small application that I want to implement I’d like to stick with MVVM. The function does not fire neither onNext nor onCompleted event and is being disposed immediately. 14. How to fix "error: escaping closure captures mutating 'self' parameter. This is not allowed. default). You can use a backtick to escape reserved words: struct Links: Codable { var `self`: String } If you don't want to use self, you can map a json key to a different property using manually defined CodingKeys: struct Links: Codable { var me: String enum CodingKeys: String, CodingKey { case me = "self" } }I find a pitfall when using value type and escaping closure together. 14 questions linked to/from Closure cannot implicitly capture a mutating self parameter. md","path":"proposals/0000-conversion-protocol. That object may have otherwise been deallocated. If the escaping closure isn’t property released, you’ve created a strong reference cycle between self and the closure. Also notice that timeLeft is defined in two. To solve this problem, Swift provides a few different ways to capture variables and resources in escaping closures. You can set initial values inside init, but then they aren't mutable later. the closure that is capturing x is escaping kind or nonescaping kind. You cannot capture self in a mutating method in an escapable closure. swift 5 escaping closure captures mutating 'self' parameter技术、学习、经验文章掘金开发者社区搜索结果。掘金是一个帮助开发者成长的社区，swift 5 escaping closure captures mutating 'self' parameter技术文章由稀土上聚集的技术大牛和极客共同编辑为你筛选出最优质的干货，用户每天都可以在这里找到技术世界的头条. As the error said, in the escaping closure, you're capturing and mutating self (actually self. I keep finding very strange SwiftUI bugs that only pop up under very specific circumstances 😅. async { self. When you enter your function, the cani value is duplicated, when you exit the function, the duplicated value, potentially modified, is written back. 函数返回. schedule (after: . By default a closure is nonescaping like your dispatch parameter, but you are calling it inside an escaping closure which probably is the closure that you pass as a parameter in getMovies function. Following code produces Escaping closure captures mutating 'self' parameter error: struct Foo { @State var count = 0 init { Timer. I understand the problem with trying to modify a struct from within a closure, but I don't know what I'd need to change to be able to update the UI, based on the results from the face detection request. SwiftUI run method on view when Published view model member value changes. value!. Learn more about TeamsSwift 5 : What's 'Escaping closure captures mutating 'self' parameter' and how to fix it. Structures and enumerations don’t allow shared mutability, as discussed in Structures and Enumerations Are Value Types. I have an escaping closure to login user; init() { userService. concurrent)//This creates a concurrent Queue var test = 10 mutating func example () { connectQueue. In Swift 1. Swift ui Escaping closure captures mutating 'self' parameter. 8. Stack Overflow | The World’s Largest Online Community for DevelopersStack Overflow Public questions & answers; Stack Overflow for Teams Where developers & technologists share private knowledge with coworkers; Talent Build your employer brand ; Advertising Reach developers & technologists worldwide; Labs The future of collective knowledge sharing; About the companyProtocol '. understood, problem is if I remove it I get warning Escaping closure captures mutating 'self' parameter – Damiano Miazzi. Stack Overflow | The World’s Largest Online Community for DevelopersSometimes you want the closure to capture self in order to make sure that it is still around by the time the closure is called. In other stack overflow questions, it was emphasized that the capture [weak self] should be used for closures that aren't owned by the class because self could be nil before the closure completes. There are several other possible errors related to closure captures being able to effectively make structs into reference types (thereby destroying any guarentees that come from being a value-type) I was trying to understand why the above code is working with the former, but not with the latter. Non-escaping closures on the other hand, cannot be stored and must instead be executed directly when used. Even in an -O build, although the heap allocation for the Bar instance is able to be optimised to a stack allocation for just the foo property, this still results in an unnecessary second reference to the Foo. Escaping closure captures mutating 'self' parameter. firstIndex (where: { $0. It is why your. ⛔️ escaping closure captures mutating 'self' parameter. A closure is said to escape a function when the closure is passed as an argument to the function, but is called after the function returns. One way that a closure can escape is. What's happening in your code is that your inout variable is escaping the lifetime of the function (by being captured in a closure that is then stored) – meaning that any changes to the inout. Locations. {"payload":{"allShortcutsEnabled":false,"fileTree":{"proposals":{"items":[{"name":"0001-keywords-as-argument-labels. Ask YouChat a question!p. e. Escaping closure captures mutating 'self' parameter. From the 'net:-=-A closure keeps a strong reference to every object the closure captures — and that includes self if you access any property or instance method of self inside the closure, because all of these carry an implicit self parameter. Here’s a quick shorthand: A non-escaping closure can refer to self implicitlyHow do I reference a mutable variable in a completion handler (so that I can access it's property's value at the time that the completion handler is eventually called, not when it is captured) while avoiding the "Escaping closure captures mutating 'self' parameter" error?I have a boolean called 'isMatched'. ' can only be used as a generic constraint because it has Self or associated typeThe problem has nothing to do with the closure, or static, or private. 1. But it always gives me the error: Closure cannot implicitly capture a mutating self parameterYou can receive messages through . The simple solution is to update your owning type to a reference once (class). I am having troubles with running view methods on published property value change. {"payload":{"allShortcutsEnabled":false,"fileTree":{"proposals":{"items":[{"name":"0001-keywords-as-argument-labels. x, closure parameter was @escaping by default, means that closure can be escape during the function body execution. The first (if provided) must be a reference to the control (the sender ). Mutating Function in Protocol Extension Where Self is UIViewController I've written a protocol and corresponding extension which utilizes a simple StringStack in tandem with a naming convention of the form "<origin>@<destination>" to perform segues between. 这个闭包并没有“逃逸 (escape)”到函数体外。. md","path":"proposals/0001-keywords-as-argument. Optional), tuples, structs, etc. Normally, a closure captures variables implicitly by using them in the body of the closure, but in this case we need to be explicit. Value types that are referenced by escaping closures will have to be moved to the heap. 3. Something like:The warning typically arises when a mutating method that modifies a variable is passed a non-escaping closure that reads from the same variable. Teams. Apr 9, 2021 at 19:27. Currently,. 1. Actually it sees that if after changing the inout parameter if the function returns or not i. . md","path":"proposals/0001-keywords-as-argument. game = game } func fetchUser (uid: String) { User. We simply call the _overlaps property's closure property, supplying the other AnyRange instance and a copy of this instance. swift. public struct LoanDetails { public var dueDate: String? public init () {} } public func getLoanDetails (_ result: @escaping (_ loanDetails. If you knew your closure wouldn’t escape the function body, you could mark the parameter with the @noescape attribute. It takes too long to use . Suppose we have a simple SwiftUI app that displays a Text object, a button to click to load the data from Firebase, and then a var that holds what the text should be. October 14, 2021. . By prefixing any closure argument with @escaping, you convey the message to the caller of a function that this closure can outlive (escape) the function call scope. 1 Why is Swift @escaping closure not working? 3. If I change to a class the error does not occurs. numberToDisplay += 1 } it just gives me an „Escaping closure captures mutating 'self' parameter” error. getInvitations (id: userId, completionHandler: { (appointment) in if appointment != nil { appointmentList = appointment self. wrappedValue. Stack Overflow | The World’s Largest Online Community for DevelopersStack Overflow | The World’s Largest Online Community for DevelopersStack Overflow Public questions & answers; Stack Overflow for Teams Where developers & technologists share private knowledge with coworkers; Talent Build your employer brand ; Advertising Reach developers & technologists worldwide; Labs The future of collective knowledge sharing; About the companyBusiness, Economics, and Finance. swift file, where there is the swiftui view, I implemented the callback and tried to update a component displayed value with a. Binding is by definition a two-way connection. Many thanks Error: Escaping closure captures mutating 'self' parameter import Combine import Foundation // Model protocol Fetchable { associatedtype T: Decodable var foo: [T] { get set } } extension Fetchable { internal mutating func fetch( from url: URL ) { let _: AnyCa. the closure that is capturing x is escaping kind or nonescaping kind. 5 Answers. {"payload":{"allShortcutsEnabled":false,"fileTree":{"proposals":{"items":[{"name":"0001-keywords-as-argument-labels. return customerList in searchCustomer happens synchronously when the data (that's obtained asynchronously from getJsonFromAPI) isn't yet available. (() -> _). main. as you can see I would need to fill my list until InvitationService Request ends but If I try to put it inside the code I got a. Suppose we have a simple SwiftUI app that displays a Text object, a button to click to load the data from Firebase, and then a var that holds what the text should be. The annotations @noescape and @autoclosure (escaping) are deprecated. Compiler gives "closure cannot implicitly capture a mutating self parameter". YouChat is You. ios; swift; swiftui; Share. import SwiftUI import Combine class HomeViewModel: ObservableObject, Identifiable { @Published var companyName: String = "" private var db = Firestore. Inside, there is another type Inner, which stores a closure that should, at some point, toggle the. x, closure parameter was @escaping by default, means that closure can be escape during the function body execution. DispatchQueue. I have the following Struct that I want to initialize, and then use its method query() to mutate its result property. implicit/non-escaping references). Yes. Creating a simple card game (Set) and I have a function in the model that deals X cards onto the deck. For example, the following VideoViewController performs such a strong capture in order to be able to. request code should take place in PeopleListVM which is a reference type, so you don't have mutating self problem. {"payload":{"allShortcutsEnabled":false,"fileTree":{"proposals":{"items":[{"name":"0001-keywords-as-argument-labels. Q&A for work. overlayVC = nil // 📝 note: captured here } } } When this code used to be "embedded" into the view controllers that used it, it worked fine, because the NSAnimationContext completion handler could capture a mutating reference to self (the view controller, which was an instance of a class). SPONSORED Build, deploy, and test paywalls to find what helps your app convert the most subscribers. Escaping closure captures mutating 'self' parameter: struct [duplicate] Closed last year. finneycanhelp. An escaping closure is like a function variable that can be performed at a later time. Capturing self in an escaping closure makes it easy to accidentally create a strong reference cycle. In this recent thread: An odd error: "Escaping closure captures mutating 'self'" - #10 by Jens, I, (well, actually @Jens), just found out that this code compiles: func test(_ callback: -> Void) { // Compiles, no need for it to be @escaping let x = callback x() } It baffles me because I don't think we have non-escaping closure types (yet). Note that this approach is wrong. onAppear as the view loads without the company name and then after a few milliseconds it appears. This method creates a DataRequest while allowing the composition of requests from individual components, such as the method and headers, while also allowing per-request RequestInterceptors and Encodable parameters. In Swift 3, it’s the other way around: closure parameters are non-escaping by default. Self will not get released until your closure has finished running. error: Converting non-escaping parameter 'completionHandler' to generic parameter 'Element' may allow it to escape By Definition: "A non escaping closure goes out of the scope and stops existing in memory as soon as the function body gets executed. struct Model { var examples: [Example] = [] /* lots of other irrelevant properties and a constructor here */ } struct Example. Properties in a struct like this (View) are immutable. Creating a simple card game (Set) and I have a function in the model that deals X cards onto the deck. . Contentview. And it's also the only option Swift allows. @Published property wrapper already gives you a Published. paul@hackingwithswift. When the closure is of escaping type, i. Does not solve the problem but breaks the code instead. In this case, it tries to capture completion, which is a non-escaping parameter. 6. This is not allowed. The escaping closure is the Button's action parameter, and the mutating function is your startTimer function. md","path":"proposals/0001-keywords-as-argument. md","path":"proposals/0001-keywords-as-argument. Add a. In your example getRequest has @escaping closure completionHandler and struct foo tries to modify itself inside this closure implementation. {"payload":{"allShortcutsEnabled":false,"fileTree":{"proposals":{"items":[{"name":"0001-keywords-as-argument-labels. 直訳すると「クロージャをエスケープすると、「self」パラメータの変化がキャプチャされる」となると思うのですが、何を言っているのかよくわかりません。. { // assign function directly instead of via capturing closure viewModel = TimerViewModel(totalTime: 15, finished: timerCallback) } var body: some View { Text("Demo") } private func. firstIndex (where: { $0. The longer version. I understand the problem with trying to modify a struct from within a closure, but I don't know what I'd need to change to be able to update the UI, based on the results from the face detection request. Escaping closure captures mutating 'self' parameter (SWIFT 5) [duplicate] Ask Question Asked 3 years ago. Hi Alexander, yes the wilderness. I'm told that this is because the analysis isn't particularly thorough, and just checks to see if the closure is immediately passed as a nonescaping parameter. Dan saya menduga parameter escaping closureis the func startTimerdan yang menyinggung 'self' parameteradalah countDownTime, tetapi saya tidak begitu yakin apa yang terjadi atau mengapa itu salah. Look at the below code:But now I'm getting a "Escaping closure captures mutating 'self' parameter" – Dante. . 2. In any case, you can't directly assign an asynchronously-obtained value to a property. id }) { return Binding ( get. Closures normally capture by reference, but it mentions in a note in the Swift Language Guide that: "As an optimization, Swift may instead capture and store a copy of a value if that value is not mutated by or outside a closure. 1 Answer. longitude are the lines I’m focusing on. {"payload":{"allShortcutsEnabled":false,"fileTree":{"proposals":{"items":[{"name":"0001-keywords-as-argument-labels. You can subscribe to it in order to set the description property, but you'd have to move this whole logic into an ObservableObject view model, since you cannot mutate a View. main. swift: 5: 14: error: escaping closure captures mutating 'self' parameter This is confusing, since the closure doesn't escape. Escaping closure captures non-escaping parameter 'promise' 0. Asperi. Even if you can bypass that, you still have the. If the escaping closure isn’t property released, you’ve created a strong reference cycle between self and the closure. init as the parameter for the output, without seeing any curlies in sight! We can use this same tactic by passing the initialiser functions for a. advanced (by: 3) OperationQueue. You can lose time this way (particularly if the app ever goes into the background). Escaping closures// This actually throws an error: Escaping closure captures mutating 'self' parameter: toastManager. An escaping closure is like a function variable that can be performed at a later time. Swift 's behavior when closures capture `inout` parameters and escape their enclosing context is a common source of confusion. If you are 100% sure that this class is available when your callback returns, use it like this { [unowned self] repoData in self. struct ContentView: View { @State var buttonText = "Initial Button Label" var body: some View { VStack { Text (buttonText) Button (action: { self. 0. Q&A for work. md","path":"proposals/0001-keywords-as-argument. So my questions are Do we have it, and If so, how do. 5 seco. Closure cannot implicitly capture self parameter. var myself = self // making a copy of self let closure = { myself. This makes sense because the to call these in the first place. Learn more about TeamsI have boiled down my code to include only the pieces necessary to reproduce the bug. (The history of the term "close over" is kind of obscure. The compiler knows that you are changing the structure by mutating dataAPI parameter. repo = repoData, it causes memory-leak because you captured self strongly. Load 7 more related questions. This means we can pass Content. . ContentView. 如果考虑到内存的. (Do you have some other reason for wanting to store the timer. But it always gives me the error: Closure cannot implicitly capture a mutating self parameter. Stack Overflow | The World’s Largest Online Community for Developers749. Escaping closure captures mutating 'self' parameter. bool1 = true which is changing the value of self. Escaping closure captures mutating 'self' parameter _ そして私がこのレッスンで何を逃したのかや私が何を逃したのかわからない. If f takes a non-escaping closure, all is well. You can also use escaping in combination with other attributes such as autoclosure and noescape. shared session. 1. We should disallow implicit capture of `inout` parameters; except in `@noescape` closures. Follow edited Dec 1, 2020 at 4:46. A copy is used to ensure that the closure can use self without having to use self, as the compiler will complain that "Escaping closure captures mutating self parameter" (hence the reason that OverlapContainer. anotherFunction(parameter: self. bar = bar } func setNewText (newString: String) { self. I'm not sure how to approach this problem. {"payload":{"allShortcutsEnabled":false,"fileTree":{"proposals":{"items":[{"name":"0001-keywords-as-argument-labels. ; class, the reference itself does not change even when you mutate its properties, because reference just points to some memory whose content is modified, but. When creating a closure in mutating function of a struct capturing self is not possible: struct Foo {var bar: Bool mutating func createClosure ()-> ()-> Bool {return {// Error: Escaping closure captures mutating 'self' parameter return self. md","path":"proposals/0001-keywords-as-argument. Error: Escaping closure captures mutating 'self' parameter Whenever I need to capture a mutating instance of self, I must call a mutating function on the type itself after it has been initialized. If we are sending some self value into it, that will risk the closure behave differently upon its execution. You capture mutating self in a mutating get, set, willSet, didSet, and mutating func. That way, the view controller will get deallocated if. ; class, the reference itself does not change even when you mutate its properties, because reference just points to some memory whose content is modified, but. ' to make capture semantics explicit". However, I want the view to get hidden automatically after 0. Escaping closure captures mutating 'self' parameter. {"payload":{"allShortcutsEnabled":false,"fileTree":{"proposals":{"items":[{"name":"0000-conversion-protocol-conventions. append(path). You are using Swift3 since you mentioned a recent dev snapshot of Swift. e aqui está uma foto do arquivo. The other solution would be to have the transition function return the new state, and have receive. Special property wrappers like @State let you mutate values later on, but you're attempting to set the actual value on the struct by using _activity = State(. So my. class , capture-list , closure , escapingclosure , struct. ' can only be used as a generic constraint because it has Self or associated type⛔️ escaping closure captures mutating 'self' parameter. {"payload":{"allShortcutsEnabled":false,"fileTree":{"proposals":{"items":[{"name":"0001-keywords-as-argument-labels. Create a HomeViewModel - this class will handle the API calls. Otherwise these models get downloaded on the first run of the image/container. When you use an escaping closure from within a struct, you can only use an immutable capture of an instance. md","path":"proposals/0001-keywords-as-argument. Here in your init in your closure, you are changing dataAPI which is part of your data model for your struct. SwiftUI Escaping closure captures mutating 'self' parameter. getById (id: uid). Look at the below code:Stack Overflow | The World’s Largest Online Community for DevelopersTeams. 如果考虑到内存的. The usual solution to mutating state inside of an escaping closure is to pass that state as an inout parameter to the closure. The type owning your call to FirebaseRef. global(). observeSingleEvent (of:with:) is most likely a value type (a struct ?), in which case a mutating context may not explicitly capture self in an @escaping closure. To have a clean architecture app, you can do something like this. You just need to observe changes of state in regular way, like below. I want to pop in response to an event on my observable. Modify variable in SwiftUI. {"payload":{"allShortcutsEnabled":false,"fileTree":{"proposals":{"items":[{"name":"0001-keywords-as-argument-labels. Forums. So, you're assigning and empty [Customer] array to @State var customerList. In order for closure queue. View Pirates Hint #3. getById. So just saving a closure in some variable doesn't necessarily mean it's leaked outside the function. But async tasks in the model are giving me a headache. This is one of the crucial differences between member func declarations and closure declarations: self has different meaning in those. create () and @escaping notification closure work on different threads. md","path":"proposals/0001-keywords-as-argument. numberToDisplay += 1 // you can't mutate a struct without mutating function self. md","path":"proposals/0001-keywords-as-argument. you may need to assign a value to the vars you have, for example, var firstName: String = "" etc. Supporting the new behavior requires changes to AST lookup, which I'm not sure we can make conditional on whether or not the. クロージャのescapingやキャプチャに関し. That way the SwiftUI runtime will manage the subscription for you, even while your view may be recreated many times. The reference to self within the closure probably switches to the new mutated instance of the struct when you modify it. Jan 6, 2020 at 11:39. The block closure is marked with the @escaping parameter attribute, which means it may escape the body of its function, and even the lifetime of self (in your context). Apr 9, 2021 at 18:16 @Dante make your closure @escaping and your function mutating, and look up what those do. A closure is said to escape a function when the closure is passed as an argument to the function, but is called after the function returns. If you intend for it to escape. The observeSingleEvent(of:with:) method. bar }}} var foo = Foo (bar: true) let closure = foo. com. Follow asked Jun 13, 2022 at 16:33. Connect and share knowledge within a single location that is structured and easy to search. func loadData(){ LoadXZYAPI() { [weak self] (data:Any?) in guard let strongSelf = self else { return } strongSelf. x and Swift 2. Value types like structs exist on the stack frame. Why does Swift 3 need @escaping annotation at all? Related.