X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=System%2FTimeout.hs;h=df33625c8d4cca3f8b51052c4c87492481d4cd5f;hb=be2750a0a11b919fb03cc070074e430f88bdfa90;hp=b1c79b3c161925cd8596fe1caabedd46d96884b9;hpb=41e8fba828acbae1751628af50849f5352b27873;p=ghc-base.git

diff --git a/System/Timeout.hs b/System/Timeout.hs
index b1c79b3..df33625 100644
--- a/System/Timeout.hs
+++ b/System/Timeout.hs
@@ -1,4 +1,7 @@
 {-# LANGUAGE CPP #-}
+#ifdef __GLASGOW_HASKELL__
+{-# LANGUAGE DeriveDataTypeable, StandaloneDeriving #-}
+#endif
 
 -------------------------------------------------------------------------------
 -- |
@@ -34,7 +37,7 @@ import Data.Unique         (Unique, newUnique)
 -- interrupt the running IO computation when the timeout has
 -- expired.
 
-data Timeout = Timeout Unique deriving Eq
+newtype Timeout = Timeout Unique deriving Eq
 INSTANCE_TYPEABLE0(Timeout,timeoutTc,"Timeout")
 
 instance Show Timeout where