diff --git a/Development/Shake/Directory.hs b/Development/Shake/Directory.hs
--- a/Development/Shake/Directory.hs
+++ b/Development/Shake/Directory.hs
@@ -46,7 +46,7 @@
     rnf (GetDirDirs a) = rnf a
 
 instance Hashable GetDir where
-    hash = hash . f
+    hashWithSalt salt = hashWithSalt salt . f
         where f (GetDir x) = (0 :: Int, x, "")
               f (GetDirFiles x y) = (1, x, y)
               f (GetDirDirs x) = (2, x, "")
diff --git a/Development/Shake/Value.hs b/Development/Shake/Value.hs
--- a/Development/Shake/Value.hs
+++ b/Development/Shake/Value.hs
@@ -15,6 +15,7 @@
 import Data.Typeable
 
 import Data.Bits
+import Data.Function
 import Data.IORef
 import Data.List
 import Data.Maybe
@@ -59,7 +60,7 @@
     rnf (Value a) = rnf a
 
 instance Hashable Value where
-    hash (Value a) = hash (typeOf a) `xor` hash a
+    hashWithSalt salt (Value a) = hashWithSalt salt (typeOf a) `xor` hashWithSalt salt a
 
 instance Eq Value where
     Value a == Value b = case cast b of
@@ -77,7 +78,10 @@
 registerWitness :: (Eq a, Show a, Typeable a, Hashable a, Binary a, NFData a) => a -> IO ()
 registerWitness x = modifyIORef witness $ Map.insert (typeOf x) (Value $ undefined `asTypeOf` x)
 
+toAscList :: Show k => Map.HashMap k v -> [(k,v)]
+toAscList = sortBy (compare `on` show . fst) . Map.toList
 
+
 data Witness = Witness
     {typeNames :: [String] -- the canonical data, the names of the types
     ,witnessIn :: Map.HashMap Word16 Value -- for reading in, the find the values (some may be missing)
@@ -85,14 +89,14 @@
     }
 
 instance Eq Witness where
-    -- type names are ordered by the Map (on hash), so likely to remain reasonably consistent
+    -- type names are ordered by TypeRep values, so should to remain reasonably consistent
     -- regardless of the order of registerWitness calls
     a == b = typeNames a == typeNames b
 
 currentWitness :: IO Witness
 currentWitness = do
     ws <- readIORef witness
-    let (ks,vs) = unzip $ Map.toList ws
+    let (ks,vs) = unzip $ toAscList ws
     return $ Witness (map show ks) (Map.fromList $ zip [0..] vs) (Map.fromList $ zip ks [0..])
 
 
@@ -100,7 +104,7 @@
     put (Witness ts _ _) = put ts
     get = do
         ts <- get
-        let ws = Map.toList $ unsafePerformIO $ readIORef witness
+        let ws = toAscList $ unsafePerformIO $ readIORef witness
         let (is,ks,vs) = unzip3 [(i,k,v) | (i,t) <- zip [0..] ts, (k,v):_ <- [filter ((==) t . show . fst) ws]]
         return $ Witness ts (Map.fromList $ zip is vs) (Map.fromList $ zip ks is)
 
diff --git a/shake.cabal b/shake.cabal
--- a/shake.cabal
+++ b/shake.cabal
@@ -1,7 +1,7 @@
 cabal-version:      >= 1.8
 build-type:         Simple
 name:               shake
-version:            0.3.8
+version:            0.3.9
 license:            BSD3
 license-file:       LICENSE
 category:           Development
@@ -66,7 +66,7 @@
         base == 4.*,
         old-time,
         directory,
-        hashable >= 1.1.2.3 && < 1.2,
+        hashable >= 1.1.2.3 && < 1.3,
         binary,
         filepath,
         process,
@@ -117,7 +117,7 @@
         base == 4.*,
         old-time,
         directory,
-        hashable >= 1.1.2.3 && < 1.2,
+        hashable >= 1.1.2.3 && < 1.3,
         binary,
         filepath,
         process,