diff --git a/persistent-test/src/CompositeTest.hs b/persistent-test/src/CompositeTest.hs
index 2ec18f726..89f5d0745 100644
--- a/persistent-test/src/CompositeTest.hs
+++ b/persistent-test/src/CompositeTest.hs
@@ -1,5 +1,6 @@
 {-# LANGUAGE DeriveGeneric #-}
 {-# LANGUAGE GeneralizedNewtypeDeriving #-}
+{-# LANGUAGE TypeOperators #-}
 {-# LANGUAGE UndecidableInstances #-} -- FIXME
 {-# OPTIONS_GHC -Wno-incomplete-uni-patterns #-}
 module CompositeTest where
diff --git a/persistent-test/src/RenameTest.hs b/persistent-test/src/RenameTest.hs
index 051497b8e..ab7f9c873 100644
--- a/persistent-test/src/RenameTest.hs
+++ b/persistent-test/src/RenameTest.hs
@@ -1,4 +1,4 @@
-{-# LANGUAGE TypeApplications, UndecidableInstances #-}
+{-# LANGUAGE TypeApplications, TypeOperators, UndecidableInstances #-}
 
 module RenameTest where
 
diff --git a/persistent-test/src/TreeTest.hs b/persistent-test/src/TreeTest.hs
index ce14f5c7c..28cfe9087 100644
--- a/persistent-test/src/TreeTest.hs
+++ b/persistent-test/src/TreeTest.hs
@@ -1,5 +1,5 @@
 {-# LANGUAGE GeneralizedNewtypeDeriving #-}
-{-# LANGUAGE RecordWildCards, UndecidableInstances #-}
+{-# LANGUAGE RecordWildCards, TypeOperators, UndecidableInstances #-}
 
 module TreeTest where
 
diff --git a/persistent-test/src/TypeLitFieldDefsTest.hs b/persistent-test/src/TypeLitFieldDefsTest.hs
index 263ccc668..1bc5f5afc 100644
--- a/persistent-test/src/TypeLitFieldDefsTest.hs
+++ b/persistent-test/src/TypeLitFieldDefsTest.hs
@@ -1,5 +1,6 @@
 {-# LANGUAGE DataKinds #-}
 {-# LANGUAGE DeriveAnyClass #-}
+{-# LANGUAGE TypeOperators #-}
 {-# LANGUAGE UndecidableInstances #-}
 {-# OPTIONS_GHC -Wno-unused-top-binds #-}
 
diff --git a/persistent-test/src/UniqueTest.hs b/persistent-test/src/UniqueTest.hs
index a9beb1f57..8eaf94a93 100644
--- a/persistent-test/src/UniqueTest.hs
+++ b/persistent-test/src/UniqueTest.hs
@@ -1,4 +1,5 @@
 {-# LANGUAGE GeneralizedNewtypeDeriving #-}
+{-# LANGUAGE TypeOperators #-}
 {-# LANGUAGE UndecidableInstances #-}
 module UniqueTest where