diff --git a/tests/Utils.hs b/tests/Utils.hs
index a597e53..bc9beae 100644
--- a/tests/Utils.hs
+++ b/tests/Utils.hs
@@ -1,3 +1,4 @@
+{-# LANGUAGE ExistentialQuantification #-}
 module Utils where
 
 import Control.Applicative