title: Can't concatenate play.twirl.api.Html objects with play 2.3
body: <p>I am trying to migrate a rather large project from play framework 2.2 to 2.3. In the project we have some helpers that do something like this:</p>
  
  <pre><code>import play.api.templates.Html;
  ...
  private object HtmlHelper {
    ...
    // Given a sequence of Htmls, return a single Html containing them
    def html(htmls: Seq[Html]): Html = htmls.foldLeft(Html(""))(_+=_)
  }
  </code></pre>
  
  <p>I have converted it to this:</p>
  
  <pre><code>import play.twirl.api.Html;
  ...
  private object HtmlHelper {
    ...
    // Given a sequence of Htmls, return a single Html containing them
    def html(htmls: Seq[Html]): Html = htmls.foldLeft(Html(""))((r,c) =&gt; r + c)
  }
  </code></pre>
  
  <p>This fails to compile with the following error:</p>
  
  <pre><code>Read from stdout: &lt;PATH&gt; type mismatch;
  Read from stdout: found   : play.twirl.api.Html
  Read from stdout: required: String
  </code></pre>
  
  <p>I've been trying to find documentation on this Html object in 2.3 but have had no luck finding anything. As far as I can see, the Html object implements Appendable, which means the + operator should work... I don't have time to learn all of Scala and this supposed "expressive" syntax is getting on my nerves.</p>
  
  <p>Any help would be appreciated.</p>