diff --git a/yesod-auth/Yesod/Auth/Email.hs b/yesod-auth/Yesod/Auth/Email.hs
index 0a731049..3829bb1e 100644
--- a/yesod-auth/Yesod/Auth/Email.hs
+++ b/yesod-auth/Yesod/Auth/Email.hs
@@ -1,3 +1,4 @@
+{-# LANGUAGE ConstrainedClassMethods #-}
 {-# LANGUAGE QuasiQuotes, TypeFamilies #-}
 {-# LANGUAGE OverloadedStrings #-}
 {-# LANGUAGE FlexibleContexts #-}