Eff.hs build log ghc 7.4.1で使うにはEff_hs_use_ghc_741.patchを当てる。

eff_hs_build.log

ghc --make Eff.hs                 [Fail]
[2 of 2] Compiling Eff              ( Eff.hs, Eff.o )

Eff.hs:96:25:
    No instance for (Functor ((->) e))
      arising from the 'deriving' clause of a data type declaration
    Possible fix:
      add an instance declaration for (Functor ((->) e))
      or use a standalone 'deriving instance' declaration,
           so you can specify the instance context yourself
    When deriving the instance for (Functor (Reader e))

Eff.hs:458:15:
    No instance for (Functor ((->) Int))
      arising from the 'deriving' clause of a data type declaration
    Possible fix:
      add an instance declaration for (Functor ((->) Int))
      or use a standalone 'deriving instance' declaration,
           so you can specify the instance context yourself
    When deriving the instance for (Functor Fresh)

Eff_hs_use_ghc_741.patch

--- Eff.hs.orig	2013-11-04 00:40:54.049122147 +0900
+++ Eff.hs	2013-11-04 00:25:32.619144784 +0900
@@ -1,4 +1,5 @@
 {-# LANGUAGE RankNTypes #-}
+{-# LANGUAGE CPP #-}
 {-# LANGUAGE TypeOperators #-}
 {-# LANGUAGE DeriveDataTypeable, GeneralizedNewtypeDeriving, DeriveFunctor #-}
 {-# LANGUAGE FlexibleContexts #-}
@@ -11,6 +12,9 @@
 module Eff where
 
 import Control.Monad
+#if __GLASGOW_HASKELL__ <= 704
+import Control.Monad.Instances
+#endif
 import Data.Typeable
 import OpenUnion1
 -- import OpenUnion3