title: haskell data definition error - Illegal literal in type (use -XDataKinds to enable)
body: <p>I am learning haskell. when I tried:</p>
  
  <pre><code>Prelude&gt; data Binary = 0 | 1
  </code></pre>
  
  <p>I got:</p>
  
  <pre><code>&lt;interactive&gt;:2:15:
      Illegal literal in type (use -XDataKinds to enable): 0
  </code></pre>
  
  <p>Even when I start ghci using <code>ghci -XDataKinds</code></p>
  
  <p>I still got:</p>
  
  <pre><code>&lt;interactive&gt;:2:15:
      parse error in constructor in data/newtype declaration: 0
  </code></pre>
  
  <p>Any one can shed some light on this?</p>