diff --git a/tn-fp-course.cabal b/tn-fp-course.cabal
index 8b5bd77..386f848 100644
--- a/tn-fp-course.cabal
+++ b/tn-fp-course.cabal
@@ -45,6 +45,7 @@ common common-all
                          FlexibleInstances
                          FunctionalDependencies
                          GADTs
+                         InstanceSigs
                          MultiParamTypeClasses
                          NamedFieldPuns
                          LambdaCase
diff --git a/tps/Scratch.hs b/tps/Scratch.hs
index 9e7e909..15e0617 100644
--- a/tps/Scratch.hs
+++ b/tps/Scratch.hs
@@ -1,7 +1,6 @@
 {-# LANGUAGE MultiParamTypeClasses #-}
 {-# LANGUAGE AllowAmbiguousTypes #-}
 {-# OPTIONS_GHC -Wno-noncanonical-monad-instances #-}
-{-# LANGUAGE InstanceSigs #-}
 {-# LANGUAGE GADTs #-}
 {-# LANGUAGE TypeFamilies #-}
 -- | Module for live trial and error