Optional Widget

Question

How to make an optional widget in Swift? WidgetBundle uses @resultBuilder, so I think we can do something similar to SwiftUI:

// SwiftUI example
if showText {
    Text("Optional text")
}

And here's what I want to get working:

struct MyWidgetBundle: WidgetBundle {
    let enableTestWidget: Bool = ...

    // Compile error: Failed to produce diagnostic for expression; 
    // please submit a bug report (https://swift.org/contributing/#reporting-bugs)
    var body: some Widget {
        Widget1()
        Widget2()
        if enableTestWidget {
            TestWidget()
        }
    }
}