diff --git a/Storage/Hashed/Darcs.hs b/Storage/Hashed/Darcs.hs
--- a/Storage/Hashed/Darcs.hs
+++ b/Storage/Hashed/Darcs.hs
@@ -1,15 +1,16 @@
-{-# LANGUAGE BangPatterns #-}
+{-# LANGUAGE ScopedTypeVariables, BangPatterns #-}
 
 -- | A few darcs-specific utility functions. These are used for reading and
 -- writing darcs and darcs-compatible hashed trees.
 module Storage.Hashed.Darcs where
 
-import Prelude hiding ( lookup )
+import Prelude hiding ( lookup, catch )
 import System.FilePath ( (</>) )
 
 import System.Directory( doesFileExist )
 import Codec.Compression.GZip( decompress, compress )
 import Control.Applicative( (<$>) )
+import Control.Exception( catch, IOException )
 
 import qualified Data.ByteString.Char8 as BS8
 import qualified Data.ByteString.Lazy.Char8 as BL8
@@ -290,7 +291,7 @@
 
 darcsPristineRefs :: FileSegment -> IO [Hash]
 darcsPristineRefs fs = do
-  con <- (darcsParseDir <$> readSegment fs) `catch` \_ -> return []
+  con <- (darcsParseDir <$> readSegment fs) `catch` \(_ :: IOException) -> return []
   return $! [ hash | (_, _, _, hash) <- con, valid hash ]
     where valid NoHash = False
           valid _ = True
diff --git a/Storage/Hashed/Tree.hs b/Storage/Hashed/Tree.hs
--- a/Storage/Hashed/Tree.hs
+++ b/Storage/Hashed/Tree.hs
@@ -28,7 +28,8 @@
     , modifyTree, updateTree, partiallyUpdateTree, updateSubtrees, overlay
     , addMissingHashes ) where
 
-import Prelude hiding( lookup, filter, all )
+import Control.Exception( catch, IOException )
+import Prelude hiding( lookup, filter, all, catch )
 import Storage.Hashed.AnchoredPath
 import Storage.Hashed.Hash
 
@@ -195,7 +196,7 @@
         let
             subtree (name, sub) =
                 do let here = path `appendPath` name
-                   sub' <- (Just <$> unstub sub) `catch` \_ -> return Nothing
+                   sub' <- (Just <$> unstub sub) `catch` \(_ :: IOException) -> return Nothing
                    case sub' of
                      Nothing -> return $ Left [(here, treeHash t_, Nothing)]
                      Just sub -> do
@@ -204,10 +205,10 @@
                               Left problems -> Left problems
                               Right tree -> Right (name, SubTree tree)
             badBlob (_, f@(File (Blob s h))) =
-              fmap (/= h) (hashFunc f `catch` (\_ -> return NoHash))
+              fmap (/= h) (hashFunc f `catch` (\(_ :: IOException) -> return NoHash))
             badBlob _ = return False
             render (name, f@(File (Blob _ h))) = do
-              h' <- (Just <$> hashFunc f) `catch` \_ -> return Nothing
+              h' <- (Just <$> hashFunc f) `catch` \(_ :: IOException) -> return Nothing
               return (path `appendPath` name, h, h')
         subs <- mapM subtree [ x | x@(_, item) <- listImmediate t_, isSub item ]
         badBlobs <- filterM badBlob (listImmediate t) >>= mapM render
diff --git a/hashed-storage.cabal b/hashed-storage.cabal
--- a/hashed-storage.cabal
+++ b/hashed-storage.cabal
@@ -1,5 +1,5 @@
 name:          hashed-storage
-version:       0.5.9
+version:       0.5.10
 synopsis:      Hashed file storage support code.
 
 description:   Support code for reading and manipulating hashed file storage
diff --git a/test.hs b/test.hs
--- a/test.hs
+++ b/test.hs
@@ -1,13 +1,16 @@
+{-# LANGUAGE ScopedTypeVariables #-}
 import Storage.Hashed.Test( tests )
+import Prelude hiding( catch )
 import Test.Framework( defaultMain )
 import System.Directory( createDirectory, removeDirectoryRecursive
                        , setCurrentDirectory )
 import Codec.Archive.Zip( extractFilesFromArchive, toArchive )
 import qualified Data.ByteString.Lazy as BL
+import Control.Exception( catch, IOException )
 
 main :: IO ()
 main = do zip <- toArchive `fmap` BL.readFile "testdata.zip"
-          removeDirectoryRecursive "_test_playground" `catch` \_ -> return ()
+          removeDirectoryRecursive "_test_playground" `catch` \(_ :: IOException) -> return ()
           createDirectory "_test_playground"
           setCurrentDirectory "_test_playground"
           extractFilesFromArchive [] zip