diff --git a/QuickCheck.cabal b/QuickCheck.cabal
--- a/QuickCheck.cabal
+++ b/QuickCheck.cabal
@@ -1,5 +1,5 @@
 name:		QuickCheck
-version:	1.0
+version:	1.1.0.0
 license:	BSD3
 license-file:	LICENSE
 author:		Koen Classen and John Hughes
@@ -17,14 +17,23 @@
 	QuickCheck provides combinators to define properties, observe
 	the distribution of test data, and define test
 	data generators.
-exposed-modules:
-	Debug.QuickCheck.Batch,
-	Debug.QuickCheck.Poly,
-	Debug.QuickCheck.Utils,
-	Debug.QuickCheck,
-	Test.QuickCheck.Batch,
-	Test.QuickCheck.Poly,
-	Test.QuickCheck.Utils,
-	Test.QuickCheck
-build-depends:	base
-extensions:	CPP
+build-type: Simple
+cabal-version: >=1.2
+
+flag split-base
+
+library
+  exposed-modules:
+          Debug.QuickCheck.Batch,
+          Debug.QuickCheck.Poly,
+          Debug.QuickCheck.Utils,
+          Debug.QuickCheck,
+          Test.QuickCheck.Batch,
+          Test.QuickCheck.Poly,
+          Test.QuickCheck.Utils,
+          Test.QuickCheck
+  if flag(split-base)
+    build-depends:	base >= 3, random
+  else
+    build-depends:	base < 3
+  extensions:	CPP
diff --git a/Setup.hs b/Setup.hs
--- a/Setup.hs
+++ b/Setup.hs
@@ -1,2 +1,6 @@
+module Main (main) where
+
 import Distribution.Simple
+
+main :: IO ()
 main = defaultMain
diff --git a/Test/QuickCheck.hs b/Test/QuickCheck.hs
--- a/Test/QuickCheck.hs
+++ b/Test/QuickCheck.hs
@@ -197,6 +197,19 @@
   coarbitrary (a, b, c, d) =
     coarbitrary a . coarbitrary b . coarbitrary c . coarbitrary d
 
+instance (Arbitrary a) => Arbitrary (Maybe a) where
+  arbitrary            = sized arbMaybe
+   where
+    arbMaybe 0 = return Nothing
+    arbMaybe n = fmap Just (resize (n-1) arbitrary)
+  coarbitrary Nothing  = variant 0
+  coarbitrary (Just x) = variant 1 . coarbitrary x
+
+instance (Arbitrary a, Arbitrary b) => Arbitrary (Either a b) where
+  arbitrary             = oneof [fmap Left arbitrary, fmap Right arbitrary]
+  coarbitrary (Left x)  = variant 0 . coarbitrary x
+  coarbitrary (Right x) = variant 1 . coarbitrary x
+
 instance Arbitrary a => Arbitrary [a] where
   arbitrary          = sized (\n -> choose (0,n) >>= vector)
   coarbitrary []     = variant 0