diff --git a/IOSpec.cabal b/IOSpec.cabal
--- a/IOSpec.cabal
+++ b/IOSpec.cabal
@@ -1,5 +1,5 @@
 Name:		        IOSpec
-Version:        	0.2.4
+Version:        	0.2.5
 License:        	BSD3
 License-file:		LICENSE
 Author:			Wouter Swierstra, Yusaku Hashimoto
diff --git a/src/Test/IOSpec/Fork.hs b/src/Test/IOSpec/Fork.hs
--- a/src/Test/IOSpec/Fork.hs
+++ b/src/Test/IOSpec/Fork.hs
@@ -1,4 +1,4 @@
-{-# LANGUAGE ExistentialQuantification, FlexibleContexts #-}
+{-# LANGUAGE ExistentialQuantification, FlexibleContexts, TypeOperators #-}
 -- | A pure specification of 'forkIO'.
 module Test.IOSpec.Fork
    (
diff --git a/src/Test/IOSpec/IORef.hs b/src/Test/IOSpec/IORef.hs
--- a/src/Test/IOSpec/IORef.hs
+++ b/src/Test/IOSpec/IORef.hs
@@ -1,4 +1,4 @@
-{-# LANGUAGE FlexibleContexts #-}
+{-# LANGUAGE FlexibleContexts, TypeOperators #-}
 -- | A pure specification of mutable variables.
 module Test.IOSpec.IORef
    (
diff --git a/src/Test/IOSpec/MVar.hs b/src/Test/IOSpec/MVar.hs
--- a/src/Test/IOSpec/MVar.hs
+++ b/src/Test/IOSpec/MVar.hs
@@ -1,4 +1,4 @@
-{-# LANGUAGE DeriveDataTypeable, FlexibleContexts #-}
+{-# LANGUAGE DeriveDataTypeable, FlexibleContexts, TypeOperators #-}
 -- | A pure specification of basic operations on MVars.
 
 module Test.IOSpec.MVar
diff --git a/src/Test/IOSpec/STM.hs b/src/Test/IOSpec/STM.hs
--- a/src/Test/IOSpec/STM.hs
+++ b/src/Test/IOSpec/STM.hs
@@ -1,4 +1,4 @@
-{-# LANGUAGE ExistentialQuantification, FlexibleContexts #-}
+{-# LANGUAGE ExistentialQuantification, FlexibleContexts, TypeOperators #-}
 
 module Test.IOSpec.STM
    (
diff --git a/src/Test/IOSpec/Teletype.hs b/src/Test/IOSpec/Teletype.hs
--- a/src/Test/IOSpec/Teletype.hs
+++ b/src/Test/IOSpec/Teletype.hs
@@ -1,4 +1,4 @@
-{-# LANGUAGE FlexibleContexts #-}
+{-# LANGUAGE FlexibleContexts, TypeOperators #-}
 -- | A pure specification of getChar and putChar.
 module Test.IOSpec.Teletype
    (