title: Initializing @State variable with values from other initialized variables
body: <p>I have 2 @State variables:</p>
  
  <pre><code>@State var test1:String
  @State var test2:String
  </code></pre>
  
  <p>I can do this:</p>
  
  <pre><code>    _test1 = State(initialValue: "test1")
      _test2 = State(initialValue: "test2")
  </code></pre>
  
  <p>and this:</p>
  
  <pre><code>    _test1 = State(initialValue: "test1")
      _test2 = _test1
  </code></pre>
  
  <p>but not this:</p>
  
  <pre><code>    _test1 = State(initialValue: "test1")
      _test2 = State(initialValue: test1 + " and test2")
  </code></pre>
  
  <p>with the error: <code>Variable 'self.test2' used before being initialized</code></p>
  
  <p>What's the reasoning behind this? Is there an appropriate way to use the value in test1 as part of test2?</p>