diff --git a/src/Data/Vec.hs b/src/Data/Vec.hs
index b21d3cc..cae01ba 100644
--- a/src/Data/Vec.hs
+++ b/src/Data/Vec.hs
@@ -3,6 +3,7 @@
 {-# LANGUAGE TypeFamilies          #-}
 {-# LANGUAGE TypeOperators         #-}
 {-# LANGUAGE StandaloneDeriving    #-}
+{-# LANGUAGE AllowAmbiguousTypes   #-}
 {-# LANGUAGE FlexibleInstances     #-}
 {-# LANGUAGE ScopedTypeVariables   #-}
 {-# LANGUAGE NoImplicitPrelude     #-}