NEW: Learn to build the incredible iOS 15 Weather app today! >>

New and improved diagnostics

Available from Swift 5.2

Paul Hudson      @twostraws

Swift 5.2 introduced a new diagnostic architecture that aims to improves the quality and precision of error messages issued by Xcode when you make a coding error. This is particularly apparent when working with SwiftUI code, where Swift would often produce false positive error messages.

For an example, consider code like this:

struct ContentView: View {
    @State private var name = 0

    var body: some View {
        VStack {
            Text("What is your name?")
            TextField("Name", text: $name)
                .frame(maxWidth: 300)
        }
    }
}

That attempts to bind a TextField view to an integer @State property, which is invalid. In Swift 5.1 this caused an error for the frame() modifier saying 'Int' is not convertible to 'CGFloat?’, but in Swift 5.2 and later this correctly identifies the error is the $name binding: Cannot convert value of type Binding<Int> to expected argument type Binding<String>.

You can find out more about the new diagnostic architecture on the Swift.org blog.

Hacking with Swift is sponsored by Essential Developer

SPONSORED Learn the most up-to-date techniques and strategies for testing new and legacy Swift code in this free practical course for iOS devs who want to become complete Senior iOS Developers.

Learn more

Sponsor Hacking with Swift and reach the world's largest Swift community!

Other changes in Swift 5.2…

Download all Swift 5.2 changes as a playground Link to Swift 5.2 changes

Browse changes in all Swift versions

 
Unknown user

You are not logged in

Log in or create account
 

Link copied to your pasteboard.