MonadFail: Make backwards-compatible

1 files changed, 3 insertions, 2 deletions

diff --git a/src/compiler/GF/Data/Operations.hs b/src/compiler/GF/Data/Operations.hs
index a9fedcaff..08fa15c3e 100644
--- a/src/compiler/GF/Data/Operations.hs
+++ b/src/compiler/GF/Data/Operations.hs
@@ -53,6 +53,7 @@ import Control.Monad (liftM,liftM2) --,ap
 
 import GF.Data.ErrM
 import GF.Data.Relation
+import qualified Control.Monad.Fail as Fail
 
 infixr 5 +++
 infixr 5 ++-
@@ -88,10 +89,10 @@ checkUnique ss = ["overloaded" +++ show s | s <- nub overloads] where
   overloaded s = length (filter (==s) ss) > 1
 
 -- | this is what happens when matching two values in the same module
-unifyMaybe :: (Eq a, MonadFail m) => Maybe a -> Maybe a -> m (Maybe a)
+unifyMaybe :: (Eq a, Fail.MonadFail m) => Maybe a -> Maybe a -> m (Maybe a)
 unifyMaybe = unifyMaybeBy id
 
-unifyMaybeBy :: (Eq b, MonadFail m) => (a->b) -> Maybe a -> Maybe a -> m (Maybe a)
+unifyMaybeBy :: (Eq b, Fail.MonadFail m) => (a->b) -> Maybe a -> Maybe a -> m (Maybe a)
 unifyMaybeBy f (Just p1) (Just p2)
   | f p1==f p2                     = return (Just p1)
   | otherwise                      = fail ""