title: What is correct syntax for @unchecked in a fold operation
body: <p>I have a fold operation something like the following:</p>
  
  <pre><code>val ops: Seq[Op] ...
  (x /: ops) { case (y, MyOp(z)) =&gt;
  ...
  }
  </code></pre>
  
  <p>An Op can have many types other than MyOp but I know in this instance that the ops are all MyOps so I want to add an @unchecked annotation to removed the compiler warning. </p>
  
  <p>Where should I place the @unchecked in this example?</p>