Haskell template error while trying out simple examples of singlotons

With both Singletons 1.0 and github master (by e8a7d6031c) against ghc 7.8.3 I am getting the following error showing some simple examples of singletons both from Richard Eisenberg's presentation and from the internet from reasonably recent blog posts and projects github (one of them is shown below):

{-# LANGUAGE TemplateHaskell #-}
{-# LANGUAGE KindSignatures #-}
{-# LANGUAGE DataKinds #-}
{-# LANGUAGE GADTs #-}
{-# LANGUAGE TypeFamilies #-}
module Main where
import Data.Singletons
import Data.Singletons.TH

main :: IO ()
main = return ()

$(singletons [d|
  data Nat = Zero | Succ Nat
  plus :: Nat -> Nat -> Nat
  plus Zero n     = n
  plus (Succ m) n = Succ (plus m n)
  |])

      

        
        
        
      

    

all attempts lead to the same errors:

The exact Name ‘t_a6fM’ is not in scope
  Probable cause: you used a unique Template Haskell name (NameU), 
  perhaps via newName, but did not bind it
  If that it, then -ddump-splices might be useful

The exact Name ‘t_a6fN’ is not in scope
  Probable cause: you used a unique Template Haskell name (NameU), 
  perhaps via newName, but did not bind it
  If that it, then -ddump-splices might be useful

      

        
        
        
      

    

I'm new to Template Haskell, so this could be a painfully obvious mistake, but can someone tell me what I'm doing wrong or point me in the right direction?

ddump splices output from ghc: http://lpaste.net/2641476385360576512