diff --git a/haddock-api.cabal b/haddock-api.cabal
--- a/haddock-api.cabal
+++ b/haddock-api.cabal
@@ -1,6 +1,6 @@
 cabal-version:        3.0
 name:                 haddock-api
-version:              2.29.0
+version:              2.29.1
 synopsis:             A documentation-generation tool for Haskell libraries
 description:          Haddock is a documentation-generation tool for Haskell
                       libraries
diff --git a/src/Haddock/Backends/Xhtml.hs b/src/Haddock/Backends/Xhtml.hs
--- a/src/Haddock/Backends/Xhtml.hs
+++ b/src/Haddock/Backends/Xhtml.hs
@@ -15,6 +15,7 @@
 {-# LANGUAGE NamedFieldPuns   #-}
 {-# LANGUAGE TupleSections    #-}
 {-# LANGUAGE TypeApplications #-}
+{-# LANGUAGE TypeFamilies     #-}
 {-# LANGUAGE BangPatterns     #-}
 
 module Haddock.Backends.Xhtml (