anchor.diff:  
       interface Renderer with
   
  -        member renderer.RenderContext =
  -            renderer.RenderContext :> obj
  -
  -        member renderer.TryLoadRenderAsset assetTag =
  -            SdlRenderer.tryLoadRenderAsset assetTag renderer
  -
           member renderer.PopMessages () =
               let messages = renderer.RenderMessages
               renderer.RenderMessages <- List ()
  
positive.code:         { MockRenderer : unit }
  
      interface Renderer with
          member renderer.RenderContext = obj ()
          member renderer.TryLoadRenderAsset _ = None
          member renderer.PopMessages () = List ()
          member renderer.ClearMessages () = ()
          member renderer.EnqueueMessage _ = ()
  
negative.code:         | _ ->
              Log.trace ("Render error - could not set render target to display buffer due to '" + SDL.SDL_GetError () + ".")
  
      /// Get the render context.
      static member getRenderContext renderer =
          renderer.RenderContext
  
      /// Make a Renderer.
      static member make renderContext =
          let renderer =
  