title: view bounds are deprecated; use an implicit parameter instead
body: <p>I recently upgraded to Scala 2.13, and now am being warned about a deprecation. My function looks like so:</p>
  <pre class="lang-scala prettyprint-override"><code>implicit def convertGeneralResult[A &lt;% ToResponseMarshallable, B &lt;% ToResponseMarshallable](r: Either[A, B]) =
    r.fold[ToResponseMarshallable](identity, identity)
  </code></pre>
  <p>The deprecation warning reads (I actually have two of them, one for each type parameter A/B):</p>
  <blockquote>
  <p>view bounds are deprecated; use an implicit parameter instead.<br />
  example: instead of <code>def f[A &lt;% Int](a: A)</code> use <code>def f[A](a: A)(implicit ev: A =&gt; Int)</code></p>
  </blockquote>
  <p>I'm not entirely sure how to apply the suggested fix in my case though.</p>