title: Trailing comma in a type
body: <p>What the heck is the following type:</p>
  
  <pre><code>(Int, =&gt; Double) =&gt; String
  </code></pre>
  
  <p>Note the trailing comma after <code>Int</code>. Apparently it is not a syntactic loophole, but something different from</p>
  
  <pre><code>(Int =&gt; Double) =&gt; String
  </code></pre>
  
  <p>E.g. when using overloading:</p>
  
  <pre><code>trait Foo {
    def bar(x: (Int, =&gt; Double) =&gt; String): Unit
    def bar(x: (Int  =&gt; Double) =&gt; String): Unit
  }
  </code></pre>