An escaping closure is like a function variable that can be performed at a later time. 0. 2. if don’t want to escape closure parameters mark it as. completion (self. both options aim to mutate self within a non-escaping closure. This proposal does not yet specify how to control the calling convention of the self parameter for methods. Class _PointQueue is implemented in both. e. @Published property wrapper already gives you a Published. Using this. Prior to Swift 3 (specifically the build that ships with Xcode 8 beta 6), they would default to being escaping – you would have to mark them @noescape in order to prevent them from being stored or captured, which guarantees they won't outlive the duration of the. Escaping closure captures mutating 'self' parameter (SWIFT 5) [duplicate] Ask Question Asked 3 years ago. I am having troubles with running view methods on published property value change. Or search Stack Overflow for "closure cannot implicitly capture a mutating self parameter" (search with quotes around the message). Here. I'd suggest moving asynchronous code like this to an. I'm not sure how to approach this problem. DispatchQueue. Closure parameters are non-escaping by default, rather than explicitly being annotated with @noescape. 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. In case of [weak self] you still need to explicitly write self. Swift. My question is do I need to use [unowned self] when the. wrappedValue. ios. Structures and enumerations don’t allow shared mutability, as discussed in Structures and Enumerations Are Value Types. Follow asked Jun 13, 2022 at 16:33. when accessing instance properties/methods when acknowledging that you capture self strongly by using [self]. About;. md","path":"proposals/0001-keywords-as-argument. Is it possible to write a property wrapper that can fetch data from some API and update a SwiftUI view upon receiving the data in a similar way to how @FetchRequest fetches data from Core Data and updates the view with whatever it finds?. 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. The whole point is the closure captures and can modify state outside itself. bar = bar } func setNewText (newString: String) { self. I'm trying to subscribe to an observable generated by a combineLatest, after flatMap. Swift: Capture inout parameter in closures that escape the called function 45 Swift 3. I'm having a hard time constructing an example for such a retain cycle on the top of my head, what am I. just as when using. Teams. anotherFlag = value } var body: some View {. this AF. 0 Error: Escaping closures can only capture inout parameters explicitly by value Escaping closure captures mutating 'self' parameter I understand that the line items. non-escaping. Creating a simple card game (Set) and I have a function in the model that deals X cards onto the deck. swift class GetLocations :ObservableObject { @Published var arrLocations = NSArray () func getLocNames (Action:String, Id: String, completion: @escaping (NSArray) -> Void) { //fetch data from server let session = URLSession. But if you make it @escaping, you get error: escaping closure captures mutating 'self' parameter. "Escaping closure captures mutating 'self' parameter. In Swift the semantics of self reference being captured are not allowed to be explicit, thus referring to any member of an object inside a closure requires you to show your full commitment to capturing with self. 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'. 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. 2 Answers. if self. postStore. Escaping closure captures mutating 'self' parameter, Firebase. {"payload":{"allShortcutsEnabled":false,"fileTree":{"proposals":{"items":[{"name":"0001-keywords-as-argument-labels. 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. 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. ' can only be used as a generic constraint because it has Self or associated type. 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. Swift protocol error: 'weak' cannot be applied to non-class type. Struct data assignment error: closure cannot implicitly capture a mutating self parameter 0 Decode JSON Data on Swift 4 returns nil エラー文です. This is one of the crucial differences between member func declarations and closure declarations: self has different meaning in those. Look at the below code:But now I'm getting a "Escaping closure captures mutating 'self' parameter" – Dante. 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). Stack Overflow. Applying borrow and take modifiers to the self parameter of methods. Hi, I’m new to Swift and also to SwiftUI. . Use @escaping to indicate that a closure parameter may escape. When I debug with breakpoints it shows Disposables. Structures and enumerations don’t allow shared mutability, as discussed in Structures and Enumerations Are Value Types. . 函数执行闭包(或不执行). But to be sure that self exists at the moment when completionHandleris called compiler needs to copy self. Values are captured in closures which basically means that it references values until the block of code is executed. When the closure is of escaping type, i. 9,028 12 54 77. repo = repoData, it causes memory-leak because you captured self strongly. Escaping closure captures mutating 'self' parameter. 1 Why is Swift @escaping closure not working? 3. Value types like structs exist on the stack frame. See c… I'm refactoring my app to use protocol and value type as much as possible, so I did a lot of experiments to understand how to use them properly. Cannot assign to property: 'self' is immutable problem. 1 Answer. players and each row has a . I have the following Struct that I want to initialize, and then use its method query() to mutate its result property. Hi Alexander, yes the wilderness. async { self. 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. I understand that the line items. Binding is by definition a two-way connection. We should disallow implicit capture of `inout` parameters; except in `@noescape` closures. ). init (initialValue. 0. dev. Escaping Closures. In Swift 3, inout parameters are no longer allowed to be captured by @escaping closures, which eliminates the confusion of expecting a pass-by-reference. そしてこれがファイルの写真です. numberToDisplay += 1 } it just gives me an „Escaping closure captures mutating 'self' parameter” error. 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. SwiftUI Escaping closure captures mutating 'self' parameter. When you declare a function that takes a closure as one of its parameters, you can write @escaping before the parameter’s type to indicate that the closure is allowed to escape. return customerList in searchCustomer happens synchronously when the data (that's obtained asynchronously from getJsonFromAPI) isn't yet available. Escaping closure captures mutating 'self' parameter You’re now watching this thread. The problem with capturing mutating self in an @escaping closure in a struct is there are really only two choices in how Swift might theoretically attempt to do it. sync { // Launch CUDA kernel try!Escaping closures ( @escaping) is a keyword that provides information about the life cycle of a closure that passes as an argument to the function. {"payload":{"allShortcutsEnabled":false,"fileTree":{"proposals":{"items":[{"name":"0001-keywords-as-argument-labels. 4. md","path":"proposals/0001-keywords-as-argument. It never occurred to me that I can use this approach to "work around" the "Escaping closure captures mutating self parameter" error! Will certainly try it next time when I need it. . numberToDisplay += 1 // you can't mutate a struct without mutating function self. md","path":"proposals/0001-keywords-as-argument. The first is to capture a reference to the struct, but in many cases it lives on the stack. The full syntax for a closure body is { (parameters) -> return type in statements } If you don't provide a list of parameters, you need to use the anonymous argument $0 / $1 syntax mentioned above. I tried to write an "editor" class that could retain a reference to a property on a different object for later mutation. The short version. With RevenueCat Paywalls you can customize native, remotely configurable paywall templates and optimize them with Experiments. Stack Overflow | The World’s Largest Online Community for Developers{"payload":{"allShortcutsEnabled":false,"fileTree":{"proposals":{"items":[{"name":"0001-keywords-as-argument-labels. getById. dataTask (with. bar }}} var foo = Foo (bar: true) let closure = foo. This is what separates a closure (which "closes over" the scope where it was created) and an anonymous function (which does not). [self] in is implicit, for. Load 7 more related questions Show fewer related questions Sorted by: Reset to. This can lead to retain cycles for which I recommend reading my article Weak self and unowned self explained in Swift to better understand how values are captured. – ctietze. {"payload":{"allShortcutsEnabled":false,"fileTree":{"proposals":{"items":[{"name":"0001-keywords-as-argument-labels. Swift 5 : What's 'Escaping closure captures mutating 'self' parameter' and how to fix it (3 answers) Closed last year. create () and @escaping notification closure work on different threads. When you declare a function that takes a closure as one of its parameters, you can write @escaping before the parameter’s type to indicate that the closure is allowed to escape. Currently,. contextMenu with the option to call editName() from the individual. Stack Overflow | The World’s Largest Online Community for DevelopersStack Overflow | The World’s Largest Online Community for Developers{"payload":{"allShortcutsEnabled":false,"fileTree":{"proposals":{"items":[{"name":"0001-keywords-as-argument-labels. Escaping closure captures mutating 'self' parameter: struct [duplicate] Closed last year. 2. 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. startTimer(with: self. Stack Overflow | The World’s Largest Online Community for Developers749. md","path":"proposals/0001-keywords-as-argument. NEW: Learn SwiftData for free with my all-new book! >>. I am trying to use it inside a struct, but I am not able to access any instance methods. Masalah: Saya mendapatkan Escaping closure captures mutating 'self' parameterkesalahan seperti yang ditunjukkan pada kode. getById (id: uid). Unfortunately, without seeing the closure, I cannot tell you why the closure is escaping. 0. That way the SwiftUI runtime will manage the subscription for you, even while your view may be recreated many times. To have a clean architecture app, you can do something like this. I am trying to code an observable for NSManagedObjectContext save () operation with no success. md","path":"proposals/0001-keywords-as-argument. Struct data assignment error: closure cannot implicitly capture a mutating self parameter 0 Decode JSON Data on Swift 4 returns nilエラー文です ・Escaping closure captures mutating 'self' parameter 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。 クロージャのescapingやキャプチャに関しては理解しているつもりです。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. So my. It gives the error, Instance members cannot be used on type. In Swift 3, it’s the other way around: closure parameters are non-escaping by default. The first (if provided) must be a reference to the control (the sender ). 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. 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. 14. md","path":"proposals/0001-keywords-as-argument. The type owning your call to FirebaseRef. The observeSingleEvent(of:with:) method. Worse, one attempt flagged a warning that the behavior may be undefined and the use of a mutating function will be removed in a later version of Swift. @autoclosure (escaping) is now written as @autoclosure @escaping. Connect and share knowledge within a single location that is structured and easy to search. Even if you can bypass that, you still have the problem of using self before all of its variables are initialized ( toggleBinding specifically). Hi Alexander, yes the wilderness. That's the meaning of a mutating self parameter . Swift, actor: Actor-isolated property 'scanning' can not be mutated from a non-isolated context. {"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. md","path":"proposals/0001-keywords-as-argument. 6. md","path":"proposals/0001-keywords-as-argument. In structs copy means creating new instance. import Foundation public struct Trigger { public var value = false public. You just need to observe changes of state in regular way, like below. This is one of the crucial differences between member func declarations and closure declarations: self has different meaning in those. 当函数结束时,传递的闭包离开函数作用域,并且没有其他的引用指向该闭包。. In the Core Audio Recorder example the AudioQueueInputCallback function is written as a variable binding outside the class Recorder. You could also move the code to a separate function, but still declare those vars with an initail value in init() – workingdog support Ukraine{"payload":{"allShortcutsEnabled":false,"fileTree":{"proposals":{"items":[{"name":"0001-keywords-as-argument-labels. In Swift 3, it’s the other way around: closure parameters are non-escaping by default. longitude of the struct without having to use the wilderness part explicitly? Capturing an inout parameter, including self in a mutating method. You are using Swift3 since you mentioned a recent dev snapshot of Swift. Does not solve the problem but breaks the code instead. . Now that we’re no longer returning the Counter instance, we’ve stopped making a separate copy of it. Value types are copied (at least effectively) on assignment, so if a closure captures a mutable value type which copy is being mutated? Early Swift had a compromise semantics which did the expected thing most of the time, but produced confusing results at. October 14, 2021. lazy implies that the code only runs once. g. S. The type owning your call to FirebaseRef. swift: 5: 14: error: escaping closure captures mutating 'self' parameter This is confusing, since the closure doesn't escape. Hot Network Questions Relative Pronoun explanation in a german quote1. Which mean they cannot be mutated. 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. global(). Escaping closure captures mutating 'self' parameter. Learn more about Collectives if self. swift. md","path":"proposals/0001-keywords-as-argument. However, you’re not allowed to let that inout parameter escape. In order for closure queue. 将闭包传递给函数. 0 Swift for loop is creating new objects. If I change to a class the error does not occurs. ⛔️ escaping closure captures mutating 'self' parameter. people. . firstIndex (where: { $0. append(str) modifies the parent ContentView object out of dataTask closure and that is not good for some reason. I need to fetch data before view loads and display the data in a button text. 将闭包传递给函数. I have a StateWrapper struct that conforms to DynamicProperty, allowing it to hold state that a SwiftUI view can access and react to. Otherwise these models get downloaded on the first run of the image/container. readFirebase () }) { Text ("Click. However, I want the view to get hidden automatically after 0. It is written in my Model. Here, the performLater function accepts an escaping closure as its parameter. 15 . implicit/non-escaping references). 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. Learn more here. md","path":"proposals/0001-keywords-as-argument. 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. Variable assignment with mutating functionality. createClosure closure To work around this you can. Dev Forum Visibility. It registers a sink and saves the cancellable inside the view which makes the subscriber live as long as the view itself does. Load 7 more related questions. So, you're assigning and empty [Customer] array to @State var customerList. 1 Answer. If you want to run the Docker image in a complete offline environment, you need to add the --build-arg with_models=true 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. The function that "animates" your struct change should be outside it, in UILogic , for example. just as when. CryptoStack Overflow | The World’s Largest Online Community for DevelopersPrevious ID SR-9743 Radar rdar://problem/56835205 Original Reporter CTMacUser (JIRA User) Type Bug Status Resolved Resolution Cannot Reproduce Attachment: Download Environment macOS Mojave 10. Non-Escaping Closures. func loadData(){ LoadXZYAPI() { [weak self] (data:Any?) in guard let strongSelf = self else { return } strongSelf. That's straightforward. Sponsor the site. If n were copied into the closure, this couldn't work. This is not allowed. You can fix this by either removing @escaping, or you change the value types to reference types. . Hi Swift community, The review of SE-0377: borrow and take parameter ownership modifiers begins now and runs through November 8, 2022. Actually you must capture weak self in each closure if you assume that viewController may be dismissed at some time during load. 函数返回. Asking for help, clarification, or responding to other answers. Type, completionHandler: @escaping (String?)->Void)When a closure is. 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. Is deck a property of self? If so, you need to be explicit that the closure is capturing a reference to self because of the potential for creating a circular reference. Query() sends and fetches JSON data, then decodes it to a String. x, closure parameter was @escaping by default, means that closure can be escape during the function body execution. SPONSORED Elevate your skills from design to SwiftUI by joining Design to SwiftUI, where you'll become skilled in weaving in unique design elements that enhance both aesthetics and user experience. md","path":"proposals/0001-keywords-as-argument. I would suggest you to use class instead of struct. being explicitly added to referenced identifiers. 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. Escaping closure captures mutating 'self' parameter (I really need help!) – SwiftUI – Hacking with Swift forums. Even the name UILogic , while just a name, hints that you may need to rethink your use of the MVVM architecture. 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. 1 Answer. e. Do I need to use a class in this case? Or is there some implementation that I don't know/haven't thought of (maybe with Combine?)? Any advice is much appreciated! P. Escaping closures are closures that have the possibility of executing after a function returns. h has been modified since the module file. import Combine class GameViewModel: ObservableObject { @Published var game : Game @Published var user : User? init (game: Game) { self. I have created a very simplified example to explain it: The View: import SwiftUI struct ContentView: View { @ ObservedObject var viewModel: ViewModel var body: some. global(qos: . Accessing an actor's isolated state from within a SwiftUI view. I am having troubles with running view methods on published property value change. Q&A for work. answered Dec 22, 2015 at 15:23. Basically, @escaping is valid only on closures in function parameter position. When you declare a function that takes a closure as one of its parameters, you can write @escaping before the parameter’s type to indicate that the closure is allowed to escape. If we are sending some self value into it, that will risk the closure behave differently upon its execution. I first wrote the editor class to receive a closure for reading, and a closure for writing. Swift ui Escaping closure captures mutating 'self' parameter. You can capture them strongly, weakly, or unowned. Locations. 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). 函数返回. Swift: How to wait for an asynchronous, @escaping closure (inline) Hot Network Questions Writing songs on piano that are meant for a guitar-led bandfunc exampleFunction() { functionWithEscapingClosure(onSuccess: { result in self. Escaping closure captures mutating 'self' parameter. The simple solution is to update your owning type to a reference once (class). Aggregates, such as enums with associated values (e. state) { newState in // depending on newState your decision here presentationMode. Class _PointQueue is implemented in both. 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. Hot. schedule (after: . Swift 5: O que é o 'fechamento de escape captura o parâmetro' self 'mutante' e como corrigi-lo . Closure cannot implicitly capture a mutating self parameter, while using it on mutating Int method I'm trying to create an extension for Int, that increments its value progressively through time. (The history of the term "close over" is kind of obscure. login { (didError, msg) in } }. This has been asked and answered before. implicit/non-escaping references). 1 (20G224) Additional Detail from JIRA Votes 0 Component/s Compiler Labels Bug Assigne. game = game } func fetchUser (uid: String) { User. {"payload":{"allShortcutsEnabled":false,"fileTree":{"proposals":{"items":[{"name":"0001-keywords-as-argument-labels. 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. Stack Overflow | The World’s Largest Online Community for DevelopersStack Overflow | The World’s Largest Online Community for DevelopersPrevious ID SR-9743 Radar rdar://problem/56835205 Original Reporter CTMacUser (JIRA User) Type Bug Status Resolved Resolution Cannot Reproduce Attachment: Download Environment macOS Mojave 10. Search ⌃ K KThe selector must take either zero, one, or two parameters and those parameters can only be very specific parameters. Xcode return: Escaping closure captures mutating 'self' parameter. 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. s: The way you're setting self. 1. Do I need to use a class in this case? Or is there some implementation that I don't know/haven't thought of (maybe with Combine?)? Any advice is much appreciated! P. Escaping closure captures mutating 'self' parameter. global(). {"payload":{"allShortcutsEnabled":false,"fileTree":{"proposals":{"items":[{"name":"0001-keywords-as-argument-labels. 8,478 6 6 gold badges 39 39 silver badges 53 53 bronze badges. Don't do that, just store the expiry time. In closure declarations any identifier not declared as a parameter is captured from the environment outside of that closure. I want to pop in response to an event on my observable. Create a HomeViewModel - this class will handle the API calls. 0. When you declare a function that takes a closure as one of its parameters, you can write @escaping before the parameter’s type to indicate that the closure is allowed to escape. Forums. md","path":"proposals/0001-keywords-as-argument. An escaping closure can cause a strong. dismiss() } } } swiftui; combine; Share. If the escaping closure isn’t property released, you’ve created a strong reference cycle between self and the closure. Learn more about TeamsSwift 5 : What's 'Escaping closure captures mutating 'self' parameter' and how to fix it. Stack Overflow | The World’s Largest Online Community for DevelopersActually it sees that if after changing the inout parameter if the function returns or not i. Here in your init in your closure, you are changing dataAPI which is part of your data model for your struct. content = content() } To use that I will do. For example, I have a form that is shown as a model sheet. You capture mutating self in a mutating get, set, willSet, didSet, and mutating func. md","path":"proposals/0001-keywords-as-argument. This means we can pass Content. non-escaping. 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. Look at the below code:Stack Overflow | The World’s Largest Online Community for DevelopersTeams. The usual solution to mutating state inside of an escaping closure is to pass that state as an inout parameter to the closure. Connect and share knowledge within a single location that is structured and easy to search. Mutating regular member var get error: "Cannot assign to property: 'self' is immutable" "Cannot use mutating member on immutable value: 'self' is immutable" struct porque: View { @State private var flag = false private var anotherFlag = false mutating func changeMe(_ value: Bool) { self. For a small application that I want to implement I’d like to stick with MVVM. ⛔. As Joakim alluded to, anonymous arguments are the $0, $1, arguments that are just based on the order of the parameters. AhmedEls. The @escaping attribute indicates that the closure will be called sometime after the function ends. The only change SE-0269 results in is that you don't need to explicitly write out self. In this case, it tries to capture completion, which is a non-escaping parameter. 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)Closure cannot implicitly capture a mutating self parameter. increase() // may work } If you change model to reference type, i. sorted (by: { $0. e. If you knew your closure wouldn’t escape the function body, you could mark the parameter with the @noescape attribute. you may need to assign a value to the vars you have, for example, var firstName: String = "" etc. timeLeft)}) { A simple solution is to change Times to be a class instead of a struct. For example, that variable may be a local. 3. Additionally, my issue has to do with the fact that it is not recognizing. This is not allowed. Binding is by definition a two-way connection. (The history of the term "close over" is kind of obscure. I've tried using Timer in ContentView to call a function that updates it, but I can't capture self in its init (Escaping closure captures mutating 'self' parameter) or have a @objc function in the view (@objc can only be used with members of classes, @objc protocols, and concrete extensions of classes). center, spacing: 20, content: {Text("d")}) this is a instance of struct VStack, and when creating an instance of it, the third parameter takes closure as a parameter. . 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. {"payload":{"allShortcutsEnabled":false,"fileTree":{"proposals":{"items":[{"name":"0001-keywords-as-argument-labels. 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. for me anyway. When you use an escaping closure from within a struct, you can only use an immutable capture of an instance.