diff --git a/checkers.cabal b/checkers.cabal
--- a/checkers.cabal
+++ b/checkers.cabal
@@ -1,5 +1,5 @@
 Name:                checkers
-Version:             0.4.0
+Version:             0.4.1
 Cabal-Version:       >= 1.6
 Synopsis:            Check properties on standard classes and data structures.
 Category:            Testing
diff --git a/src/Test/QuickCheck/Utils.hs b/src/Test/QuickCheck/Utils.hs
--- a/src/Test/QuickCheck/Utils.hs
+++ b/src/Test/QuickCheck/Utils.hs
@@ -1,3 +1,4 @@
+{-# OPTIONS_GHC -Wall #-}
 -----------------------------------------------------------------------------
 -- |
 -- Module      :  Test.QuickCheck.Utils
@@ -27,21 +28,21 @@
 
 isAssociativeBy :: (Show a,Testable prop) 
 		=> (a -> a -> prop) -> Gen a -> (a -> a -> a) -> Property
-isAssociativeBy (===) src (#) = 
+isAssociativeBy (=~=) src (#) = 
      	forAll src $ \ a ->
      	forAll src $ \ b ->
      	forAll src $ \ c ->
-	((a # b) # c) === (a # (b # c))
+	((a # b) # c) =~= (a # (b # c))
 
 isAssociative :: (Arbitrary a,Show a,Eq a) => (a -> a -> a) -> Property
 isAssociative = isAssociativeBy (==) arbitrary
 
 isCommutableBy :: (Show a,Testable prop) 
 	       => (b -> b -> prop) -> Gen a -> (a -> a -> b) -> Property
-isCommutableBy (===) src (#) =
+isCommutableBy (=~=) src (#) =
 	forAll src $ \ a ->
 	forAll src $ \ b ->
-	(a # b) === (b # a)
+	(a # b) =~= (b # a)
 
 isCommutable :: (Arbitrary a,Show a,Eq b) => (a -> a -> b) -> Property
 isCommutable = isCommutableBy (==) arbitrary