IO/Monad Issues

votes.hs

------------------------------------------------
Version that works:
------------------------------------------------
   -- | Resources passed to featureResources in constructor
    getVoteResource = (resourceAt "/packages/vote") {
      resourceDesc = [(GET, "Get the number of votes a package has.")],
      resourceGet  = [("json", returnOne)]
    }

    -- | Trivial json response
    returnOne _ = do
        isInMap <- fmap(Map.member "c") $ readMemState votesCache
        let
          arr = if isInMap
            then [("inMap", "True")]
            else [("inMap", "False")]

        ok. toResponse $ toJSON arr

--------------------------------------------------
Version that doesn't work
--------------------------------------------------
   -- | Resources passed to featureResources in constructor
    getVoteResource = (resourceAt "/packages/vote") {
      resourceDesc = [(GET, "Get the number of votes a package has.")],
      resourceGet  = [("json", returnOne)]
    }

    -- | Trivial json response
    returnOne _ = do
        votesMap <- readMemState votesCache
        let
          arr = if "c" `Map.member` votesMap
            then [("inMap", "True")]
            else [("inMap", "False")]

        ok. toResponse $ toJSON arr

Distribution/Server/Features/Ranking.hs:79:32:
    Couldn't match type ‘m0 Response’ with ‘Response’
    Expected type: Distribution.Server.Framework.Resource.ServerResponse
      Actual type: DynamicPath
                   -> ServerPartT
                        (Control.Monad.Trans.Error.ErrorT ErrorResponse IO) (m0 Response)
    In the expression: returnOne
    In the expression: ("json", returnOne)