Xcode13 Swift4 Swift compiler error

You may need to provide more info to let readers try to help solving your issue. Can you show the source file which contains the compile error? (Please do not forget to show the code a text using Code Block.) The whole message shown in the debug console may also be useful. Info about your project, such as iOS app or macOs app, or used third party libraries if any...and so on.

Is it a compiler error or a compiler warning ?