title: Scala's wrong forward reference error
body: <pre><code>private def foo(a:A):B = a match{
      case A(...) =&gt;
          val x = a.b //error: wrong forward reference a
          ...
  }
  </code></pre>
  
  <p>Where b is not mentioned in A(...), if that matters.</p>
  
  <p>I've tried my luck on Google, but I seem to find only posts of people having errors involving forward references but no explanation of what this particular error actually means.</p>
  
  <p>Would appreciate it if somebody could help me out.</p>