Experiments with current state of SwiftUI beta. Second state property broke it so Ill probably end here.

GlobalSwiftUIBindings.swift

import SwiftUI

extension Binding {
    init(global keyPath: KeyPath<Bindings, Binding>) {
        self = bindings[keyPath: keyPath]
    }
}

struct Bindings {
    @Binding var anotherOne: Bool
    @Binding var isOn: Bool
}
var bindings: Bindings!
var firstRun = true

struct Store {
    var isOn: Bool = true
    var anotherOne: Bool = false
    
}

struct ContentView : View {
    @State var store: Store = Store()
    var body: some View {
        print("content")
        if firstRun {
            firstRun = false
            bindings = Bindings(
                anotherOne: $store.anotherOne,
                isOn: $store.isOn
            )
        }
        
        return Child()
    }
}

struct Child: View {
    var body: some View {
        print("child")
        return VStack {
//            Child4() //uncomment to make 4 work, 2 break
            Child2()
        }
    }
}
struct Child2: View {
    //we still need this as a property, using global bindings.$isOn directly in body doesnt work
    @Binding(global: \.$isOn) var isOn: Bool
    
    var body: some View {
        print("child2")
        return VStack {
        Toggle(isOn: $isOn) {
            Text(String(describing: isOn))
        }
        Child3()
        }
    }
}

struct Child3: View {
    var body: some View {
        //when child2 changes, it also recomputes child3, except first time. Layout may be the reason, but its still strange this isnt called on the first change
        print("child3")
        return Child4()
    }
}

struct Child4: View {
    @Binding(global: \.$anotherOne) var anotherOne: Bool
    var body: some View {
        print("child4")
        //this binding can trigger statechange but this view never gets recomputed. Instead, child2 gets recomputed
        return Toggle(isOn: $anotherOne) {
                Text(String(describing: anotherOne))
            }
    }
}


#if DEBUG
struct ContentView_Previews : PreviewProvider {
    static var previews: some View {
        ContentView()
    }
}
#endif