I assume your goal with [0] is to be able to say `ViewContainer()` and have it wrap an `EmptyView`? You can do that like the following:

  class ViewContainer<ViewType: View> {
      var view: ViewType
      init(view: ViewType) {
          self.view = view
      }
  }
  
  extension ViewContainer where ViewType == EmptyView {
      convenience init() {
          self.init(view: EmptyView())
      }
  }

With this code, writing `ViewContainer()` will produce a `ViewContainer<EmptyView>`. Writing `ViewContainer<Text>()` will fail with an error (as expected).

Note that since this is statically-typed, the following will fail:

  let container = ViewContainer()
  container.view = Text("wat")

If you want to be able to do that, you'd have to write something like

  let container = ViewContainer(view: AnyView(EmptyView()))
  container.view = AnyView(Text("wat"))