title: Is this a bug of Kotlin REPL?
body: <p>I can define a value in Kotlin REPL like this(recursively) without getting an error:</p>
  
  <pre><code>val s: String = s
  </code></pre>
  
  <p>And now I get an 's' with the type of NotNull but the value of null.<br/>
  And I can do something with this <code>NotNull</code> value with a NPE:</p>
  
  <pre><code>&gt;&gt;&gt; val s: String = s
  
  &gt;&gt;&gt; s.length
  java.lang.NullPointerException
  </code></pre>
  
  <p>You can try it on your own Kotlin REPL, it works every time.</p>
  
  <p>I am using Kotlin version 1.1.2-3.</p>