title: Why can't class fields be var?
body: <pre><code>class A
  {
      A()
      {
          var x = 5;   // this is allowed
      }
  
      var _x = 5;   // the compiler is unhappy
  }
  </code></pre>
  
  <p>I guess the compiler must be able to deduce the type for the member variable just the same way it does it for the local one. So what's the difference?</p>