title: How do you declare a type alias in a scala constructor?
body: <p>If I have a class that takes a tuple in its constructor among other values such as:</p>
  
  <pre><code>class Foo(a: Int, b: String, c: (Int, String)) 
  </code></pre>
  
  <p>How do I use an abstract type to give the tuple a more descriptive name in a lightweight fashion (without wrapping it in a new class):</p>
  
  <pre><code>class Foo(a: Int, b: String, c: Dave) 
  </code></pre>
  
  <p>I'm not sure how to bring a type alias in scope (or if this is the best thing to do):</p>
  
  <pre><code>type Dave = (Int, String) 
  </code></pre>
  
  <p>Is there a convention for where to define types in this way (or should I be defining case classes and wrapping everything...)? </p>
  
  <p>I appreciate that it does not make sense in a lot of situations but if I'm really only looking for a more descriptive name is it possible?</p>
  
  <p>Thanks!</p>