diff --git a/src/HPath/IO/Errors.hs b/src/HPath/IO/Errors.hs
index 0153981..b252d2a 100644
--- a/src/HPath/IO/Errors.hs
+++ b/src/HPath/IO/Errors.hs
@@ -9,6 +9,7 @@
 --
 -- Provides error handling.
 
+{-# LANGUAGE DeriveDataTypeable #-}
 {-# LANGUAGE ScopedTypeVariables #-}
 
 module HPath.IO.Errors