1 files changed, 28 insertions, 45 deletions
diff --git a/libraries/base/Control/Monad/ST.hs b/libraries/base/Control/Monad/ST.hs
index 397b072533..0508b6e50f 100644
--- a/libraries/base/Control/Monad/ST.hs
+++ b/libraries/base/Control/Monad/ST.hs
@@ -1,11 +1,14 @@
-{-# LANGUAGE CPP #-}
+{-# LANGUAGE CPP, SafeImports #-}
+#if sh_SAFE_DEFAULT
+{-# LANGUAGE Safe #-}
+#endif
 
 -----------------------------------------------------------------------------
 -- |
 -- Module      :  Control.Monad.ST
 -- Copyright   :  (c) The University of Glasgow 2001
 -- License     :  BSD-style (see the file libraries/base/LICENSE)
--- 
+--
 -- Maintainer  :  libraries@haskell.org
 -- Stability   :  experimental
 -- Portability :  non-portable (requires universal quantification for runST)
@@ -16,55 +19,35 @@
 --
 -----------------------------------------------------------------------------
 
-module Control.Monad.ST
-  (
-        -- * The 'ST' Monad
-        ST,             -- abstract, instance of Functor, Monad, Typeable.
-        runST,          -- :: (forall s. ST s a) -> a
-        fixST,          -- :: (a -> ST s a) -> ST s a
-
-        -- * Converting 'ST' to 'IO'
-        RealWorld,              -- abstract
-        stToIO,                 -- :: ST RealWorld a -> IO a
-
-        -- * Unsafe operations
-        unsafeInterleaveST,     -- :: ST s a -> ST s a
-        unsafeIOToST,           -- :: IO a -> ST s a
-        unsafeSTToIO            -- :: ST s a -> IO a
-      ) where
-
-#if defined(__GLASGOW_HASKELL__)
-import Control.Monad.Fix ()
-#else
-import Control.Monad.Fix
+module Control.Monad.ST (
+          module Control.Monad.ST.Safe
+#if !sh_SAFE_DEFAULT
+        -- * Unsafe Functions
+        , unsafeInterleaveST
+        , unsafeIOToST
+        , unsafeSTToIO
 #endif
+    ) where
 
-#include "Typeable.h"
+import safe Control.Monad.ST.Safe
 
-#if defined(__GLASGOW_HASKELL__)
-import GHC.ST           ( ST, runST, fixST, unsafeInterleaveST )
-import GHC.Base         ( RealWorld )
-import GHC.IO           ( stToIO, unsafeIOToST, unsafeSTToIO )
-#elif defined(__HUGS__)
-import Data.Typeable
-import Hugs.ST
-import qualified Hugs.LazyST as LazyST
-#endif
-
-#if defined(__HUGS__)
-INSTANCE_TYPEABLE2(ST,sTTc,"ST")
-INSTANCE_TYPEABLE0(RealWorld,realWorldTc,"RealWorld")
+#if !sh_SAFE_DEFAULT
+import qualified Control.Monad.ST.Unsafe as U
 
-fixST :: (a -> ST s a) -> ST s a
-fixST f = LazyST.lazyToStrictST (LazyST.fixST (LazyST.strictToLazyST . f))
+{-# DEPRECATED unsafeInterleaveST, unsafeIOToST, unsafeSTToIO
+              "Please import from Control.Monad.ST.Unsafe instead; This will be removed in the next release"
+ #-}
 
+{-# INLINE unsafeInterleaveST #-}
 unsafeInterleaveST :: ST s a -> ST s a
-unsafeInterleaveST =
-    LazyST.lazyToStrictST . LazyST.unsafeInterleaveST . LazyST.strictToLazyST
-#endif
+unsafeInterleaveST = U.unsafeInterleaveST
+
+{-# INLINE unsafeIOToST #-}
+unsafeIOToST :: IO a -> ST s a
+unsafeIOToST = U.unsafeIOToST
 
-#if !defined(__GLASGOW_HASKELL__)
-instance MonadFix (ST s) where
-        mfix = fixST
+{-# INLINE unsafeSTToIO #-}
+unsafeSTToIO :: ST s a -> IO a
+unsafeSTToIO = U.unsafeSTToIO
 #endif