1 files changed, 3 insertions, 3 deletions

diff --git a/Data/BitSyntax.hs b/Data/BitSyntax.hs
index dbb43f45..6d14d0c1 100644
--- a/Data/BitSyntax.hs
+++ b/Data/BitSyntax.hs
@@ -131,15 +131,15 @@ data BitBlock = -- | Unsigned 8-bit int
 
 -- Encodes a member of the Bits class as a series of bytes and returns the
 -- ByteString of those bytes.
-getBytes :: (Integral a, Bounded a, Bits a) => a -> BS.ByteString
+getBytes :: (Integral a, Bounded a, FiniteBits a) => a -> BS.ByteString
 getBytes input =
     let getByte _ 0 = []
         getByte x remaining = (fromIntegral $ (x .&. 0xff)) :
                               getByte (shiftR x 8) (remaining - 1)
         in
-        if (bitSize input `mod` 8) /= 0
+        if (finiteBitSize input `mod` 8) /= 0
            then error "Input data bit size must be a multiple of 8"
-           else BS.pack $ getByte input (bitSize input `div` 8)
+           else BS.pack $ getByte input (finiteBitSize input `div` 8)
 
 -- Performs the work behind PackBits
 packBits :: (Word8, Int, [Word8])  -- ^ The current byte, the number of bits