title: Is the use of previously defined members as part of later members in an enum definition legal?
body: <pre><code>namespace ValueType {
    enum Enum {
      Boolean = 0,
      Float = 1,
      Double,
      SInt = 8,
      SLong,
      UInt = SInt + (1 &lt;&lt;4),
      ULong = SLong + (1 &lt;&lt; 4)
    };
  }
  </code></pre>