diff --git a/ghc/lib/ghc/UnsafeST.lhs b/ghc/lib/ghc/UnsafeST.lhs
index 4a9c705129b2170fe045a5ba9fe725418fd1a99e..f185990cb62d908def773657b9d39b2bcbf81801 100644
--- a/ghc/lib/ghc/UnsafeST.lhs
+++ b/ghc/lib/ghc/UnsafeST.lhs
@@ -26,11 +26,11 @@ import GHC
 
 
 unsafeInterleaveST :: ST s a -> ST s a
-unsafeInterleaveST (ST m) = ST $ \ s ->
+unsafeInterleaveST (ST m) = ST ( \ s ->
     let
 	(r, new_s) = m s
     in
-    (r, s)
+    (r, s))
 
 unsafePerformPrimIO	:: PrimIO a -> a
 	-- We give a fresh definition here.  There are no