perhaps more clear type

Utility/FileSystemEncoding.hs

@@ -12,6 +12,7 @@ import qualified GHC.IO.Encoding as Encoding
 import Foreign.C
 import System.IO
 import System.IO.Unsafe
+import qualified Data.Hash.MD5 as MD5
 
 {- Sets a Handle to use the filesystem encoding. This causes data
  - written or read from it to be encoded/decoded the same
@@ -28,8 +29,7 @@ withFilePath :: FilePath -> (CString -> IO a) -> IO a
 withFilePath fp f = Encoding.getFileSystemEncoding
 	>>= \enc -> GHC.withCString enc fp f
 
-{- Encodes a FilePath into a String of encoded bytes, applying the
- - filesystem encoding.
+{- Encodes a FilePath into a Str, applying the filesystem encoding.
  -
  - This use of unsafePerformIO is belived to be safe; GHC's interface
  - only allows doing this conversion with CStrings, and the CString buffer
@@ -37,7 +37,7 @@ withFilePath fp f = Encoding.getFileSystemEncoding
  - effects.
  -}
 {-# NOINLINE encodeFilePath #-}
-encodeFilePath :: FilePath -> String
-encodeFilePath fp = unsafePerformIO $ do
+encodeFilePath :: FilePath -> MD5.Str
+encodeFilePath fp = MD5.Str $ unsafePerformIO $ do
 	enc <- Encoding.getFileSystemEncoding
 	GHC.withCString enc fp $ GHC.peekCString Encoding.char8