diff --git a/src/HPath/IO.hs b/src/HPath/IO.hs
index 3243651..9692561 100644
--- a/src/HPath/IO.hs
+++ b/src/HPath/IO.hs
@@ -136,6 +136,7 @@ import Data.Maybe
 import Data.Monoid
   (
     (<>)
+  , mempty
   )
 import Data.Word
   (