"Failed to produce diagnostic for expression; please submit a bug report and include the project"

Why am I getting this error?


struct ContentView: View {
  var folders = ["Folder1", "Folder2"]
  @State var searchString = ""
  @State var newFolderName = ""
  var body: some View { //This is where the error shows...
    ZStack {
      NavigationView {
      List {
        TextField("Search", text: $searchString)
        Section(header:
              Text("On My iPhone")
          .font(.title3)
          .fontWeight(.bold)
          .foregroundColor(.black)) {
        ForEach (folders, id: \.self) { folderName in
          FolderCell(name: folderName)
           
      }
        .textCase(nil)
      }
      .listStyle(InsetGroupedListStyle())
      .navigationTitle("Folders")
      .toolbar {
        ToolbarItemGroup(placement: .navigationBarTrailing) {
          Button("Edit") {
          print("Edit")
          }
        }
        ToolbarItemGroup(placement: .bottomBar) {
          Image(systemName: "folder.badge.plus")
          Image(systemName: "square.and.pencil")
           
        }
        RoundedRectangle(cornerRadius: 7)
          .fill(Color(.systemGray4))
          .frame(width: 200, height: 299, alignment: .center)
        VStack {
          Text("New Folder")
          Text("Enter a name for this folder")
          TextField("Name", text: $newFolderName)
        }
         
       }
      }
    }
  }
}


struct ContentView_Previews: PreviewProvider {
  static var previews: some View {
    ContentView()
  }
}

struct FolderCell: View {
  var name: String
  var body: some View {
    HStack {
      Image(systemName: "Folder")
      Text(name)
    }
  }
}
}

Move the code below out of the toolbar list. This is not a toolbar type hence the error.

 RoundedRectangle(cornerRadius: 7)
          .fill(Color(.systemGray4))
          .frame(width: 200, height: 299, alignment: .center)
        VStack {
          Text("New Folder")
          Text("Enter a name for this folder")
          TextField("Name", text: $newFolderName)
        }
"Failed to produce diagnostic for expression; please submit a bug report and include the project"
 
 
Q