title: SwiftUI with Xcode 11 beta 7 not updating contents of List / ForEach
body: <p>I've been trying a simple feature to add new entries to a List. The View will just add a new generated. item (no need for user input).</p>
  
  <pre><code>struct PeopleList: View {
  @ObservedObject var people: PersonStore
  var body: some View {
      NavigationView {
          VStack {
              Section {
                  Button(action: add) {
                      Text("Add")
                  }
              }
              Section {
                  List {
                      ForEach(people.people) { person in
  
                          NavigationLink(destination: PersonDetail(person: person)) {
                              PersonRow(person: person)
                          }
                      }
                  }
              }
          }
      }
      .navigationBarTitle(Text("People"))
      .listStyle(GroupedListStyle())
  }
  
  func add() {
      let newID = (people.people.last?.id ?? 0) + 1
  
      self.people.people.append(Person(id: newID, name: ""))
  }
  }
  </code></pre>
  
  <p>This used to work in previous betas, but for some reason it's not working anymore. When I click on Add, the App does call the <code>add()</code> function and adds the new entry to the array, but the View is not updated at all.</p>
  
  <p>These are the support classes:</p>
  
  <pre><code>    class PersonStore: ObservableObject {
  
      var people: [Person] {
          willSet {
              willChange.send()
          }
      }
  
      init(people: [Person] = []) {
          self.people = people
      }
  
      var willChange = PassthroughSubject&lt;Void, Never&gt;()
  }
  
  class Person: ObservableObject, Identifiable {
  
      var id: Int = 0 {
          willSet {
              willChange.send()
          }
      }
  
      var name: String {
          willSet {
              willChange.send()
          }
      }
  
       init(id: Int, name: String) {
          self.id = id
          self.name = name
      }
  
      var willChange = PassthroughSubject&lt;Void, Never&gt;()
  }
  
  #if DEBUG
  
  let data = [
      Person(id: 1, name: "David"),
      Person(id: 2, name: "Anne"),
      Person(id: 3, name: "Carl"),
      Person(id: 4, name: "Amy"),
      Person(id: 5, name: "Daisy"),
      Person(id: 6, name: "Mike"),
  ]
  
  #endif
  </code></pre>
  
  <p>And the support views:</p>
  
  <pre><code>struct PersonRow: View {
  
      @ObservedObject var person: Person
  
      var body: some View {
          HStack {
              Image(systemName: "\(person.id).circle")
              Text(person.name)
          }.font(.title)
      }
  }
  
  struct PersonDetail: View {
  
      @ObservedObject var person: Person
  
      var body: some View {
          HStack {
  
              Text("This is \(person.name)")
          }.font(.title)
      }
  }
  </code></pre>
  
  <p>I've found someone with a problem that looks a bit related here:
  <a href="https://stackoverflow.com/questions/57702108/swiftui-view-content-not-reloading-if-observedobject-is-a-subclass-of-uiviewco">SwiftUI: View content not reloading if @ObservedObject is a subclass of UIViewController. Is this a bug or am I missing something?</a>
  and here:
  <a href="https://stackoverflow.com/questions/57127878/swiftui-binding-doesnt-refresh-view">SwiftUI @Binding doesn&#39;t refresh View</a></p>