title: Yesod generateFormPost - No instance for (RenderMessage master0 FormMessage)
body: <p>I tried to follow this screencast by Michael Snoyman <a href="http://vimeo.com/39646807" rel="nofollow">http://vimeo.com/39646807</a>. However, it seems changes to the i18n causes that code to fail. I can't find any information on how to solve this problem on a scaffolded site and I can't quite make sense of the information given here <a href="http://www.yesodweb.com/book/internationalization" rel="nofollow">http://www.yesodweb.com/book/internationalization</a>.</p>
  
  <p>This is the error i get, referring to code in Home.hs:</p>
  
  <pre><code>No instance for (RenderMessage master0 FormMessage)
    arising from a use of `generateFormPost'
  Possible fix:
    add an instance declaration for (RenderMessage master0 FormMessage)
  In a stmt of a 'do' block:
    (formWidget, enctype) &lt;- generateFormPost noteForm
  In the expression:
    do { (formWidget, enctype) &lt;- generateFormPost noteForm;
         defaultLayout ($(widgetFile "notes")) }
  In an equation for `getNotesR':
      getNotesR
        = do { (formWidget, enctype) &lt;- generateFormPost noteForm;
               defaultLayout ($(widgetFile "notes")) }
  </code></pre>
  
  <p>The information seems pretty clear, the problem is I can't figure out how to add an instance declaration for (RenderMessage master0 FormMessage).</p>
  
  <p>Here's the code I added to Home.hs</p>
  
  <pre><code>noteForm = renderBootstrap $ Note
      &lt;$&gt; areq textField "Title" Nothing
      &lt;*&gt; areq textField "Content" Nothing
  
  getNotesR = do
      (formWidget, enctype) &lt;- generateFormPost noteForm
      defaultLayout $(widgetFile "notes")
  
  postNotesR = return ()
  getNoteR noteId = return ()
  </code></pre>
  
  <p>Ant the following is from templates/notes.hamlet</p>
  
  <pre><code>&lt;form method=post enctype=#{enctype}&gt;
      ^{formWidget}
      &lt;input type=submit&gt;
  </code></pre>