X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=compiler%2FsimplCore%2FCoreMonad.lhs;h=90b062f1f04d199ed73baa4273a7b3574f2e7437;hb=22b34988e2b156593d7cfc9b72d6cc0ab471a1d2;hp=ae45ba40790f1e9b8f42dfa849ec36b00a9e30b7;hpb=5a230f0eba0ed06df341a8180f8521d9f869745a;p=ghc-hetmet.git

diff --git a/compiler/simplCore/CoreMonad.lhs b/compiler/simplCore/CoreMonad.lhs
index ae45ba4..90b062f 100644
--- a/compiler/simplCore/CoreMonad.lhs
+++ b/compiler/simplCore/CoreMonad.lhs
@@ -125,9 +125,12 @@ instance Applicative CoreM where
 
 -- For use if the user has imported Control.Monad.Error from MTL
 -- Requires UndecidableInstances
+#if __GLASGOW_HASKELL__ > 606
+-- see instance MonadPlus IOEnv
 instance MonadPlus IO => MonadPlus CoreM where
     mzero = CoreM (const mzero)
     m `mplus` n = CoreM (\rs -> unCoreM m rs `mplus` unCoreM n rs)
+#endif
 
 instance MonadUnique CoreM where
     getUniqueSupplyM = do