title: Not in scope: type constructor or class
body: <p>I've a Haskell code for a game where the complete one can be found <a href="https://github.com/keera-studios/gtk-helpers/tree/master/gtk2/examples/peg-solitaire" rel="noreferrer">here</a>.</p>
  
  <p>The following is BoardMain.hs</p>
  
  <pre><code>{-# Language MultiParamTypeClasses, FunctionalDependencies #-}
  
  import Control.Monad.Trans (liftIO)
  import Graphics.UI.Gtk
  import Graphics.UI.Gtk.Layout.BackgroundContainer
  import Graphics.UI.Gtk.Board.BoardLink
  import GtkPegSolitaire
  
  
  attemptDragStart :: Board Int Tile Peg -&gt; (Int, Int) -&gt;  IO Bool
  attemptDragStart _ _ = return True
  </code></pre>
  
  <p>When I'm running this, I'm getting the following error</p>
  
  <pre><code> BoardMain.hs:39:21: error:
      Not in scope: type constructor or class ‘Board’
  
  BoardMain.hs:39:31: error:
      Not in scope: type constructor or class ‘Tile’
  
  BoardMain.hs:39:36: error:
      Not in scope: type constructor or class ‘Peg’
  </code></pre>
  
  <p>I know that I've made a small mistake. Any help is appreciated.</p>
  
  <p><code>GtkPegSolitaire.hs</code> and <code>PegSolitaire.hs</code> can be found <a href="https://github.com/keera-studios/gtk-helpers/tree/master/gtk2/examples/peg-solitaire" rel="noreferrer">here</a></p>