title: In scala macros, how to get the complete `extends` clause for a class?
body: <p>Given</p>
  
  <pre><code>trait A[T]
  class B[T] extends A[Option[T]]
  </code></pre>
  
  <p>In a macro, I can see that <code>A</code> is a supertype of <code>B</code> and <code>B</code> is a subtype of <code>A</code>, but the specifics of how the type parameters match up is missing.</p>
  
  <p>How can I get the complete <code>extends A[Option[T]]</code> information?</p>