xcode11 - Unable to infer complex closure return type with SwiftUI

Question

Following part 3 of Apple's tutorial on SwiftUI, Handling User Input, I get this error:

Unable to infer complex closure return type; add explicit type to disambiguate

I'm using the same code as the tutorial (even coping from the 'Complete' sample code doesn't resolve the error).

Does anyone have a cue what is going wrong here?

struct LandmarkRow: View {
    var landmark: Landmark

    var body: some View {
        HStack {
            landmark.image(forSize: 50)
            Text(verbatim: landmark.name)
            Spacer()

            if landmark.isFavorite {
                Image(systemName: "star.fill")
                    .imageScale(.medium)
            }
        }
    }
}

Regardless of the cause of the issue, how could you indeed add an explicit type to disambiguate here? What would the return type in such a case be?

--

Update

Apparently you should not continue with your result of the 2nd tutorial with the 3rd. Some things changed in between of the tutorials that is not documented in the tutorial. I've added the project files to Github so you can check out the diff.

It's better to start the 3rd tutorial fresh with a fresh download of the Project files of the 3rd tutorial.

Answer 1

The issue is not with the closure, but with the isFavorite property on landmark.

It is not declared on the Landmark type, and the compiler instead of showing the undeclared property error, unable to resolve the stacks build closure return type, so it shows and error there.

Great job Apple tutorial writers and even better one Xcode11 compiler.

To fix:

1. Declare isFavorite variable on the Landmark type.
2. Make sure you update the landmarkData.json for every landmark record with the isFavorite = false entry, otherwise the app will crash at runtime.