diff --git a/src/Data/Sum/Templates.hs b/src/Data/Sum/Templates.hs
index 7080aef78..26c6dc16c 100644
--- a/src/Data/Sum/Templates.hs
+++ b/src/Data/Sum/Templates.hs
@@ -1,4 +1,5 @@
 {-# LANGUAGE TemplateHaskell #-}
+{-# OPTIONS_GHC -Wno-incomplete-uni-patterns #-}
 module Data.Sum.Templates
 ( mkElemIndexTypeFamily
 , mkApplyInstance