fix noncanonical Monad instances

src/compiler/api/GF/CompileInParallel.hs

@@ -236,11 +236,10 @@ instance Functor m => Functor (CollectOutput m) where
    fmap f (CO m) = CO (fmap (fmap f) m)
 
 instance (Functor m,Monad m) => Applicative (CollectOutput m) where 
-  pure = return
+  pure x = CO (return (return (),x))
   (<*>) = ap
 
 instance Monad m => Monad (CollectOutput m) where
-  return x = CO (return (return (),x))
   CO m >>= f = CO $ do (o1,x) <- m
                        let CO m2 = f x
                        (o2,y) <- m2

src/compiler/api/GF/Data/BacktrackM.hs

@@ -64,11 +64,10 @@ finalStates :: BacktrackM s () -> s -> [s]
 finalStates bm = map fst . runBM bm
 
 instance Applicative (BacktrackM s) where
-    pure = return
+    pure a = BM (\c s b -> c a s b)
     (<*>) = ap
 
 instance Monad (BacktrackM s) where
-    return a   = BM (\c s b -> c a s b)
     BM m >>= k = BM (\c s b -> m (\a s b -> unBM (k a) c s b) s b)
         where unBM (BM m) = m
 

src/compiler/api/GF/Data/ErrM.hs

@@ -34,7 +34,6 @@ fromErr :: a -> Err a -> a
 fromErr a = err (const a) id
 
 instance Monad Err where
-  return      = Ok
   Ok a  >>= f = f a
   Bad s >>= f = Bad s
 
@@ -54,7 +53,7 @@ instance Functor Err where
   fmap f (Bad s) = Bad s
 
 instance Applicative Err where
-  pure = return
+  pure = Ok
   (<*>) = ap
 
 -- | added by KJ

src/compiler/api/GF/Grammar/Lexer.x

@@ -317,11 +317,10 @@ instance Functor P where
   fmap = liftA
 
 instance Applicative P where
-  pure = return
+  pure a = a `seq` (P $ \_ s -> POk s a)
   (<*>) = ap
 
 instance Monad P where
-  return a    = a `seq` (P $ \_ s -> POk s a)
   (P m) >>= k = P $ \l s -> case m l s of
                               POk s a          -> unP (k a) l s
                               PFailed posn err -> PFailed posn err

src/compiler/api/GF/Infra/SIO.hs

@@ -53,11 +53,10 @@ newtype SIO a = SIO {unS::PutStr->IO a}
 instance Functor SIO where fmap = liftM
 
 instance Applicative SIO where
-  pure = return
+  pure x = SIO (const (pure x))
   (<*>) = ap
 
 instance Monad SIO where
-  return x = SIO (const (return x))
   SIO m1 >>= xm2 = SIO $ \ h -> m1 h >>= \ x -> unS (xm2 x) h
 
 instance Fail.MonadFail SIO where

src/compiler/api/GF/Infra/UseIO.hs

@@ -149,31 +149,6 @@ instance ErrorMonad IO where
   handle m h = catch m $ \ e -> if isUserError e
                                 then h (ioeGetErrorString e)
                                 else ioError e
-{-
--- Control.Monad.Fail import will become redundant in GHC 8.8+
-import qualified Control.Monad.Fail as Fail
-
-instance Functor IOE where fmap = liftM
-
-instance Applicative IOE where
-  pure = return
-  (<*>) = ap
-
-instance  Monad IOE where
-  return a    = ioe (return (return a))
-  IOE c >>= f = IOE $ do 
-                  x <- c          -- Err a
-                  appIOE $ err raise f x         -- f :: a -> IOE a
-
- #if !(MIN_VERSION_base(4,13,0))
-  fail = raise
- #endif
-
-instance Fail.MonadFail IOE where
-  fail = raise
-
-
--}
 
 -- | Print the error message and return a default value if the IO operation 'fail's
 useIOE :: a -> IOE a -> IO a