3 files changed, 7 insertions, 2 deletions
diff --git a/src/compiler/GF/Command/Commands.hs b/src/compiler/GF/Command/Commands.hs
index 72e57fcf5..0e5c61404 100644
--- a/src/compiler/GF/Command/Commands.hs
+++ b/src/compiler/GF/Command/Commands.hs
@@ -34,6 +34,7 @@ import Data.Maybe
 import qualified Data.Map as Map
 import GF.Text.Pretty
 import Data.List (sort)
+import qualified Control.Monad.Fail as Fail
 --import Debug.Trace
 
 
@@ -44,7 +45,7 @@ pgfEnv pgf = Env pgf mos
 
 class (Functor m,Monad m,MonadSIO m) => HasPGFEnv m where getPGFEnv :: m PGFEnv
 
-instance (Monad m,HasPGFEnv m) => TypeCheckArg m where
+instance (Monad m,HasPGFEnv m,Fail.MonadFail m) => TypeCheckArg m where
   typeCheckArg e = (either (fail . render . ppTcError) (return . fst)
                     . flip inferExpr e . pgf) =<< getPGFEnv
 
diff --git a/src/compiler/GF/Command/Commands2.hs b/src/compiler/GF/Command/Commands2.hs
index 344b6b51d..100f877a9 100644
--- a/src/compiler/GF/Command/Commands2.hs
+++ b/src/compiler/GF/Command/Commands2.hs
@@ -18,6 +18,7 @@ import Data.Maybe
 import qualified Data.Map as Map
 import GF.Text.Pretty
 import Control.Monad(mplus)
+import qualified Control.Monad.Fail as Fail
 
 
 data PGFEnv = Env {pgf::Maybe PGF,concs::Map.Map ConcName Concr}
@@ -25,7 +26,7 @@ data PGFEnv = Env {pgf::Maybe PGF,concs::Map.Map ConcName Concr}
 pgfEnv pgf = Env (Just pgf) (languages pgf)
 emptyPGFEnv = Env Nothing Map.empty
 
-class (Monad m,MonadSIO m) => HasPGFEnv m where getPGFEnv :: m PGFEnv
+class (Fail.MonadFail m,MonadSIO m) => HasPGFEnv m where getPGFEnv :: m PGFEnv
 
 instance (Monad m,HasPGFEnv m) => TypeCheckArg m where
   typeCheckArg e = do env <- getPGFEnv
diff --git a/src/compiler/GF/Command/Interpreter.hs b/src/compiler/GF/Command/Interpreter.hs
index bcb15d238..1c38edf8b 100644
--- a/src/compiler/GF/Command/Interpreter.hs
+++ b/src/compiler/GF/Command/Interpreter.hs
@@ -11,6 +11,8 @@ import GF.Infra.UseIO(putStrLnE)
 
 import Control.Monad(when)
 import qualified Data.Map as Map
+import GF.Infra.UseIO (Output)
+import qualified Control.Monad.Fail as Fail
 
 data CommandEnv m = CommandEnv {
   commands      :: Map.Map String (CommandInfo m),
@@ -22,6 +24,7 @@ data CommandEnv m = CommandEnv {
 mkCommandEnv cmds = CommandEnv cmds Map.empty Map.empty
 
 --interpretCommandLine :: CommandEnv -> String -> SIO ()
+interpretCommandLine :: (Fail.MonadFail m, Output m, TypeCheckArg m) => CommandEnv m -> String -> m ()
 interpretCommandLine env line =
   case readCommandLine line of
     Just []    -> return ()