diff --git a/Storage/Hashed/Monad.hs b/Storage/Hashed/Monad.hs
index b86a702..5d96d4d 100644
--- a/Storage/Hashed/Monad.hs
+++ b/Storage/Hashed/Monad.hs
@@ -1,4 +1,5 @@
 {-# LANGUAGE ScopedTypeVariables, BangPatterns, TypeSynonymInstances, UndecidableInstances #-}
+{-# LANGUAGE FlexibleInstances #-}
 
 -- | An experimental monadic interface to Tree mutation. The main idea is to
 -- simulate IO-ish manipulation of real filesystem (that's the state part of
diff --git a/Storage/Hashed/Tree.hs b/Storage/Hashed/Tree.hs
index 0bef0e6..c4bb669 100644
--- a/Storage/Hashed/Tree.hs
+++ b/Storage/Hashed/Tree.hs
@@ -1,4 +1,5 @@
 {-# LANGUAGE ScopedTypeVariables, MultiParamTypeClasses, FlexibleInstances #-}
+{-# LANGUAGE BangPatterns #-}
 
 -- | The abstract representation of a Tree and useful abstract utilities to
 -- handle those.