diff --git a/haddock-api/src/Haddock/Types.hs b/haddock-api/src/Haddock/Types.hs
index b6a43a9af3d33db045ac375fbab0447180377f0d..2df67c45776a6fbdfbd56c4b4ed8afc41de25ed0 100644
--- a/haddock-api/src/Haddock/Types.hs
+++ b/haddock-api/src/Haddock/Types.hs
@@ -401,6 +401,8 @@ instance (
   WFT (XOverLit (GhcPass (NoGhcTcPass p))),
   WFT (Anno (IdGhcP p)),
   WFT (Anno (IdGhcP (NoGhcTcPass p))),
+  WFT (SyntaxExprGhc p),
+  WFT (SyntaxExprGhc (NoGhcTcPass p)),
 #endif
   OutputableBndrId p)
          => Outputable (InstType (GhcPass p)) where