diff --git a/ouroboros-network/src/Ouroboros/Network/ChainFragment.hs b/ouroboros-network/src/Ouroboros/Network/ChainFragment.hs
index a648592fa6e..e1cde081dd4 100644
--- a/ouroboros-network/src/Ouroboros/Network/ChainFragment.hs
+++ b/ouroboros-network/src/Ouroboros/Network/ChainFragment.hs
@@ -74,6 +74,7 @@ module Ouroboros.Network.ChainFragment (
   foldChainFragmentSpec,
   pointOnChainFragmentSpec,
   selectPointsSpec,
+  lookupBySlotFT
   ) where
 
 import           Prelude hiding (drop, filter, head, last, length, null)