problems with happstack templates on class methods

test.hs

{-# LANGUAGE TemplateHaskell, 
             DeriveDataTypeable, 
             TypeFamilies,
             MultiParamTypeClasses #-}

module Test  where

import Data.Data
import Happstack.State

data TestComponent a b =
  TestComponent {
    next_id :: Integer,
    foo :: [(a,b)]
    } deriving (Show, Data, Typeable)
                   
instance Version (TestComponent a b)
$(deriveSerialize ''TestComponent)

instance (Serialize a, Serialize b) => Component (TestComponent a b) where
  type Dependencies (TestComponent a b) = End
  initialValue = TestComponent 0 []
  
class TestComponentC a b where
  test :: Update (TestComponent a b) ()
  test = do
    next_id_ <- fmap next_id getState
    foo_ <- fmap foo getState
    putState $ TestComponent (next_id_ + 1) foo_

$(mkMethods ''TestComponent ['test])

{--                              

with ghc-7.0.1 and happstack-state-0.5.0.4 when trying to load into ghci I get:

test.hs:1:1:
    Exception when trying to run compile-time code:
      Method is not a function: test is a Class op from Test.TestComponentC: Test.test :: forall a_0 b_1 . Test.TestComponentC a_0
                                                                                     b_1 =>
                                                                 Happstack.State.Types.Update (Test.TestComponent a_0
                                                                                                                  b_1)
                                                                                              ()
      Code: mkMethods 'TestComponent ['test]
Failed, modules loaded: none.


--}