title: What is lldb_expr in Swift Playground?
body: <p>I was trying to demonstrate basic inheritance to someone and how the super initializer is always called by default when overriding an init:</p>
  
  <pre><code>class Animal{
      init(){
          println("Animal has been initialized!")
      }
  }
  
  class Dog:Animal{
      var feet:Int = 4
  
      override init(){
          println("Dog has been initialized!")
      }
  }
  
  var d = Dog()
  </code></pre>
  
  <p>Why is it that I get <code>{__lldb_expr_380.Animal feet 4}</code> on the last line? It goes away when I create an instance variable under the animal class.</p>