diff --git a/packages/test/data/monaderror-explist.y b/packages/test/data/monaderror-explist.y
index 4ec70753..5051fc1b 100644
--- a/packages/test/data/monaderror-explist.y
+++ b/packages/test/data/monaderror-explist.y
@@ -1,5 +1,5 @@
 {
-{-# LANGUAGE FunctionalDependencies, FlexibleInstances #-}
+{-# LANGUAGE FunctionalDependencies, FlexibleInstances, MultiParamTypeClasses #-}
 module Main where
 
 import Data.Char
diff --git a/packages/test/data/monaderror.y b/packages/test/data/monaderror.y
index 5775f703..301d9299 100644
--- a/packages/test/data/monaderror.y
+++ b/packages/test/data/monaderror.y
@@ -1,5 +1,5 @@
 {
-{-# LANGUAGE FunctionalDependencies, FlexibleInstances #-}
+{-# LANGUAGE FunctionalDependencies, FlexibleInstances, MultiParamTypeClasses #-}
 module Main where
 
 import Control.Monad (when)