title: Why is the following scala experimental code not working?
body: <p>I'm trying to define a generic add function to numeric values:</p>
  
  <pre><code>def add[A](x:A, y:A): A = {
    x + y
  }
  </code></pre>
  
  <p><br/>
  console:16: error: type mismatch;
   found   : A
   required: String
           x + y
               ^
  <br/></p>
  
  <p>What's the compiler complaining about?
  Some of the stuff I've googled does not quite make sense to me at this moment.</p>