Is this a bug? and should I raise a bug with Apple for this ? Not sure if Apple would call this issue as bug. But if you have the project which can reproduce the same issue, you should better send a bug report to Apple.

When I enter it, It itself automatically switches to key called 'Appearance' When the raw key UIUserInterfaceStyle is shown as Appearance in human readable mode, that means UIUserInterfaceStyle is (at least, once was) the supported key. Appearance doesn't have Light / Dark or anything... For many values taking String value, the value would not be shown automatically. When I enter it is info.plist it doesn't get accepted... You have not clarified what you have entered on what key...

Running/debugging apps on iOS 14.5+ devices is not supported with Xcode 12.4. https://developer.apple.com/forums/thread/679482?answerId=673429022#673429022 You should better prepare an upgraded Mac and try with Xcode 12.5.

Apple Developer has mentioned that you can add 'UIUserInterfaceStyle' key to info.plist. But I checked there is no such key in list and it also gives error when you upload app to the App Store. What value have you set? Light? Some articles say it needs to be capitalized, not light.

Have you tried using single-quotes? OTHER_SWIFT_FLAGS = "$(inherited) -D COCOAPODS -Xcc '-Wno-error=non-modular-include-in-framework-module'";

Getting error build time "Cannot find type 'GADInterstitial' in scope" I guess GADInterstitial is not a type in a framework of Apple's. You should better find a better place to ask it to get better responses sooner. And better include more description of your environment and what you have done.

Every site I visited mentioned the adding that into the Build Phase. Seems you have visited only old sites or sites written by people who would not make their ways up-to-date. So I want to check, is this something that has changed recently with different versions of Xcode? Sorry, I do not remember exactly from which version this has changed.

Are there any other files I need to copy or import into my project? Nothing. Also, adding libsqlite3.tbd in the Build Phase is not needed. The module SQLite3 is made of bunch of C-language APIs. They are hard to use even for super-experienced developers. You can find some third party libraries to ease the difficulties using the SQLite3 APIs with Swift.

Can you show a complete code to reproduce the issue? Minimized would be preferable, but currently shown code lacks many parts and I cannot test it.

Thanks for showing the code. This is the worst part of your code: IntroSliderViewController() You are calling the undocumented initializer init() of IntroSliderViewController, in almost all cases, it would create a garbage object which causes Fatal error: Unexpectedly found nil. When you want to instantiate a view controller that you have defined on the storyboard with subviews and/or IBOutlets/IBActions, you need to instantiate it through the storyboard. Like this: let introSliderVC = self.storyboard?.instantiateViewController(withIdentifier: "IntroSliderViewController") self.present(introSliderVC, animated: true, completion: nil) (You need to put the right Storyboard ID IntroSliderViewController to the view controller in the Identity Inspector.)

My application crashes when I call the ViewController of the slider.  How are you showing the view controller? Using segue? Or something else? And please show the whole message you get and which line it happens.

Can you show a complete code which can reproduce the same issue?

my problem is with api documentation like we discuss earlier  In fact, the documentations of SwitfUI are far worse than poor. Maybe some words which are excluded from this site would be appropriate. I really wonder why Apple's engineers (not Document engineer, but the designers and the implementers) are not interested in writing a good documentation. But one reason you cannot read them well is that you assume things where it is not expected. You first assumed <Label, Content> would define the parameters of an initializer, but it does not. And even in C sharp, generic parameters does not define the parameters of a constructor. I do agree that SwiftUI forces us some different aspects than that of procedural programming, but there are many of such things waiting for you and stopping on a type header does not seem to be a good attitude. Anyway, check the documentation of the initializer when you want to call init of a struct.

Here it's my declaration (inside the view): Thanks. Generally, creating an @State variable of class type would be less useful in many cases. But that depends on many other things. Hope you can find the best solution for your case.

aspStatus is a Class that return to me true or false (if false, a message why its false): Thanks for showing the class. But you have not shown the declaration of aspStatus (I do not mean AspStatus), nor any code using the class AspStatus. So it does not give any useful info to me. I just don't understand your last part: In your case, from the opening brace { on line 13 of validatingLogin() to the closing brace } on line 34 is the completion handler.