title: SwiftUI Binding default value (Argument labels '(wrappedValue:)' do not match any available overloads)
body: <p>In Swift you can define default values on a struct that can be overwritten on initialization:</p>
  
  <pre class="lang-swift prettyprint-override"><code>struct myStruct {
      var a: Int = 1
  }
  var instance1 = myStruct() // instance1.a -&gt; 1 
  var instance2 = myStruct(a: 10) // instance2.a -&gt; 10
  </code></pre>
  
  <p>However when I try to apply this to Bindings in a SwiftUI view I get an error:</p>
  
  <pre class="lang-swift prettyprint-override"><code>struct MyView: View {
      @Binding var a: Bool = Binding.constant(true)
      var body: some View {
          Text("MyView")
      }
  }
  </code></pre>
  
  <pre><code>Argument labels '(wrappedValue:)' do not match any available overloads
  </code></pre>
  
  <p>I want to create a view which by default uses a constant boolean value but that can be overwritten by a "real" Binding:</p>
  
  <pre class="lang-swift prettyprint-override"><code>struct ContainerView: View {
      @State var hasSet = false
      var body: some View {
          Group {
              MyView(a: $hasSet)
              MyView() // should be equivalent to MyView(a: .constant(true))
          }
      }
  }
  </code></pre>
  
  <p>Is it possible to define such a default value for a Binding in SwiftUI?</p>