Make NoExtCon fields strict

These changes are a part of a fix for
[GHC#17992](https://gitlab.haskell.org/ghc/ghc/issues/17992).

8 files changed, 1 insertions, 57 deletions

diff --git a/haddock-api/src/Haddock/Backends/Hoogle.hs b/haddock-api/src/Haddock/Backends/Hoogle.hs
index 93ca4cfd..36001714 100644
--- a/haddock-api/src/Haddock/Backends/Hoogle.hs
+++ b/haddock-api/src/Haddock/Backends/Hoogle.hs
@@ -196,7 +196,6 @@ ppFam dflags decl@(FamilyDecl { fdInfo = info })
               -- for Hoogle, so pretend it doesn't have any.
               ClosedTypeFamily{} -> decl { fdInfo = OpenTypeFamily }
               _                  -> decl
-ppFam _ (XFamilyDecl nec) = noExtCon nec
 
 ppInstance :: DynFlags -> ClsInst -> [String]
 ppInstance dflags x =
@@ -269,7 +268,6 @@ ppCtor dflags _dat subdocs con@(ConDeclGADT { })
 
         typeSig nm ty = operator nm ++ " :: " ++ outHsType dflags (unL ty)
         name = out dflags $ map unL $ getConNames con
-ppCtor _ _ _ (XConDecl nec) = noExtCon nec
 
 ppFixity :: DynFlags -> (Name, Fixity) -> [String]
 ppFixity dflags (name, fixity) = [out dflags ((FixitySig noExtField [noLoc name] fixity) :: FixitySig GhcRn)]
diff --git a/haddock-api/src/Haddock/Backends/LaTeX.hs b/haddock-api/src/Haddock/Backends/LaTeX.hs
index 98b13756..560a0f40 100644
--- a/haddock-api/src/Haddock/Backends/LaTeX.hs
+++ b/haddock-api/src/Haddock/Backends/LaTeX.hs
@@ -349,8 +349,6 @@ ppFamDecl doc instances decl unicode =
              , equals
              , ppType unicode (unLoc rhs)
              ]
-    ppFamDeclEqn (XHsImplicitBndrs nec) = noExtCon nec
-    ppFamDeclEqn (HsIB { hsib_body = XFamEqn nec}) = noExtCon nec
 
     instancesBit = ppDocInstances unicode instances
 
@@ -358,7 +356,6 @@ ppFamDecl doc instances decl unicode =
 ppFamHeader :: FamilyDecl DocNameI  -- ^ family header to print
               -> Bool                 -- ^ unicode
               -> LaTeX
-ppFamHeader (XFamilyDecl nec) _ = noExtCon nec
 ppFamHeader (FamilyDecl { fdLName = L _ name
                         , fdTyVars = tvs
                         , fdInfo = info
@@ -378,7 +375,6 @@ ppFamHeader (FamilyDecl { fdLName = L _ name
       NoSig _               -> empty
       KindSig _ kind        -> dcolon unicode <+> ppLKind unicode kind
       TyVarSig _ (L _ bndr) -> equals <+> ppHsTyVarBndr unicode bndr
-      XFamilyResultSig nec  -> noExtCon nec
 
     injAnn = case injectivity of
       Nothing -> empty
@@ -797,7 +793,6 @@ ppSideBySideConstr subdocs unicode leader (L _ con) =
                             -- ++AZ++ make this prepend "{..}" when it is a record style GADT
                             , ppLType unicode (getGADTConType con)
                             ]
-      XConDecl nec -> noExtCon nec
 
     fieldPart = case (con, getConArgs con) of
         -- Record style GADTs
@@ -831,7 +826,6 @@ ppSideBySideConstr subdocs unicode leader (L _ con) =
         [ l <+> text "\\enspace" <+> r
         | (l,r) <- ppSubSigLike unicode (unLoc (getGADTConType con)) argDocs subdocs (dcolon unicode)
         ]
-      XConDecl nec -> noExtCon nec
 
 
     -- don't use "con_doc con", in case it's reconstructed from a .hi file,
@@ -851,7 +845,6 @@ ppSideBySideField subdocs unicode (ConDeclField _ names ltype _) =
     -- don't use cd_fld_doc for same reason we don't use con_doc above
     -- Where there is more than one name, they all have the same documentation
     mbDoc = lookup (extFieldOcc $ unLoc $ head names) subdocs >>= fmap _doc . combineDocumentation . fst
-ppSideBySideField _ _ (XConDeclField nec) = noExtCon nec
 
 
 -- | Pretty-print a bundled pattern synonym
@@ -1018,7 +1011,6 @@ ppHsTyVarBndr :: Bool -> HsTyVarBndr DocNameI -> LaTeX
 ppHsTyVarBndr _ (UserTyVar _ (L _ name)) = ppDocName name
 ppHsTyVarBndr unicode (KindedTyVar _ (L _ name) kind) =
   parens (ppDocName name) <+> dcolon unicode <+> ppLKind unicode kind
-ppHsTyVarBndr _ (XTyVarBndr nec) = noExtCon nec
 
 ppLKind :: Bool -> LHsKind DocNameI -> LaTeX
 ppLKind unicode y = ppKind unicode (unLoc y)
diff --git a/haddock-api/src/Haddock/Backends/Xhtml/Decl.hs b/haddock-api/src/Haddock/Backends/Xhtml/Decl.hs
index 97db7b86..c22afeed 100644
--- a/haddock-api/src/Haddock/Backends/Xhtml/Decl.hs
+++ b/haddock-api/src/Haddock/Backends/Xhtml/Decl.hs
@@ -327,8 +327,6 @@ ppFamDecl summary associated links instances fixities loc doc decl splice unicod
         , Nothing
         , []
         )
-    ppFamDeclEqn (XHsImplicitBndrs nec) = noExtCon nec
-    ppFamDeclEqn (HsIB { hsib_body = XFamEqn nec}) = noExtCon nec
 
 
 -- | Print a pseudo family declaration
@@ -353,7 +351,6 @@ ppFamHeader :: Bool                 -- ^ is a summary
             -> Bool                 -- ^ is an associated type
             -> FamilyDecl DocNameI  -- ^ family declaration
             -> Unicode -> Qualification -> Html
-ppFamHeader _ _ (XFamilyDecl nec) _ _ = noExtCon nec
 ppFamHeader summary associated (FamilyDecl { fdInfo = info
                                            , fdResultSig = L _ result
                                            , fdInjectivityAnn = injectivity
@@ -393,7 +390,6 @@ ppResultSig result unicode qual = case result of
     NoSig _               -> noHtml
     KindSig _ kind        -> dcolon unicode  <+> ppLKind unicode qual kind
     TyVarSig _ (L _ bndr) -> equals <+> ppHsTyVarBndr unicode qual bndr
-    XFamilyResultSig nec  -> noExtCon nec
 
 
 --------------------------------------------------------------------------------
@@ -751,7 +747,6 @@ ppShortDataDecl summary dataInst dataDecl pats unicode qual
     isH98     = case unLoc (head cons) of
                   ConDeclH98 {} -> True
                   ConDeclGADT{} -> False
-                  XConDecl{}    -> False
 
     pats1 = [ hsep [ keyword "pattern"
                    , hsep $ punctuate comma $ map (ppBinder summary . getOccName) lnames
@@ -785,7 +780,6 @@ ppDataDecl summary links instances fixities subdocs loc doc dataDecl pats
     isH98     = case unLoc (head cons) of
                   ConDeclH98 {} -> True
                   ConDeclGADT{} -> False
-                  XConDecl{}    -> False
 
     header_ = topDeclElem links loc splice [docname] $
              ppDataHeader summary dataDecl unicode qual <+> whereBit <+> fix
@@ -868,7 +862,6 @@ ppShortConstrParts summary dataInst con unicode qual
           , noHtml
           , noHtml
           )
-      XConDecl nec -> noExtCon nec
 
   where
     occ        = map (nameOccName . getName . unLoc) $ getConNamesI con
@@ -938,7 +931,6 @@ ppSideBySideConstr subdocs fixities unicode pkg qual (L _ con)
                               , ppLType unicode qual HideEmptyContexts (getGADTConType con)
                               , fixity
                               ]
-      XConDecl nec -> noExtCon nec
 
     fieldPart = case (con, getConArgs con) of
         -- Record style GADTs
@@ -967,7 +959,6 @@ ppSideBySideConstr subdocs fixities unicode pkg qual (L _ con)
       ConDeclGADT{} ->
         ppSubSigLike unicode qual (unLoc (getGADTConType con))
                      argDocs subdocs (dcolon unicode) HideEmptyContexts
-      XConDecl nec -> noExtCon nec
 
     -- don't use "con_doc con", in case it's reconstructed from a .hi file,
     -- or also because we want Haddock to do the doc-parsing, not GHC.
@@ -1011,14 +1002,12 @@ ppSideBySideField subdocs unicode qual (ConDeclField _ names ltype _) =
     -- don't use cd_fld_doc for same reason we don't use con_doc above
     -- Where there is more than one name, they all have the same documentation
     mbDoc = lookup (extFieldOcc $ unLoc $ head names) subdocs >>= combineDocumentation . fst
-ppSideBySideField _ _ _ (XConDeclField nec) = noExtCon nec
 
 
 ppShortField :: Bool -> Unicode -> Qualification -> ConDeclField DocNameI -> Html
 ppShortField summary unicode qual (ConDeclField _ names ltype _)
   = hsep (punctuate comma (map ((ppBinder summary) . rdrNameOcc . unLoc . rdrNameFieldOcc . unLoc) names))
     <+> dcolon unicode <+> ppLType unicode qual HideEmptyContexts ltype
-ppShortField _ _ _ (XConDeclField nec) = noExtCon nec
 
 
 -- | Pretty print an expanded pattern (for bundled patterns)
@@ -1125,7 +1114,6 @@ ppHsTyVarBndr _       qual (UserTyVar _ (L _ name)) =
 ppHsTyVarBndr unicode qual (KindedTyVar _ name kind) =
     parens (ppDocName qual Raw False (unLoc name) <+> dcolon unicode <+>
             ppLKind unicode qual kind)
-ppHsTyVarBndr _ _ (XTyVarBndr nec) = noExtCon nec
 
 ppLKind :: Unicode -> Qualification -> LHsKind DocNameI -> Html
 ppLKind unicode qual y = ppKind unicode qual (unLoc y)
diff --git a/haddock-api/src/Haddock/GhcUtils.hs b/haddock-api/src/Haddock/GhcUtils.hs
index b83920ee..83d23d1b 100644
--- a/haddock-api/src/Haddock/GhcUtils.hs
+++ b/haddock-api/src/Haddock/GhcUtils.hs
@@ -78,12 +78,6 @@ getInstLoc (TyFamInstD _ (TyFamInstDecl
   -- in particular, we need to dig a bit deeper to pull out the entire
   -- equation. This does not happen for data family instances, for some reason.
   { tfid_eqn = HsIB { hsib_body = FamEqn { feqn_rhs = L l _ }}})) = l
-getInstLoc (ClsInstD _ (XClsInstDecl nec)) = noExtCon nec
-getInstLoc (DataFamInstD _ (DataFamInstDecl (HsIB _ (XFamEqn nec)))) = noExtCon nec
-getInstLoc (TyFamInstD _ (TyFamInstDecl (HsIB _ (XFamEqn nec)))) = noExtCon nec
-getInstLoc (XInstDecl nec) = noExtCon nec
-getInstLoc (DataFamInstD _ (DataFamInstDecl (XHsImplicitBndrs nec))) = noExtCon nec
-getInstLoc (TyFamInstD _ (TyFamInstDecl (XHsImplicitBndrs nec))) = noExtCon nec
 
 
 
@@ -170,7 +164,6 @@ nubByName f ns = go emptyNameSet ns
 hsTyVarNameI :: HsTyVarBndr DocNameI -> DocName
 hsTyVarNameI (UserTyVar _ (L _ n))     = n
 hsTyVarNameI (KindedTyVar _ (L _ n) _) = n
-hsTyVarNameI (XTyVarBndr nec) = noExtCon nec
 
 hsLTyVarNameI :: LHsTyVarBndr DocNameI -> DocName
 hsLTyVarNameI = hsTyVarNameI . unLoc
@@ -178,11 +171,9 @@ hsLTyVarNameI = hsTyVarNameI . unLoc
 getConNamesI :: ConDecl DocNameI -> [Located DocName]
 getConNamesI ConDeclH98  {con_name  = name}  = [name]
 getConNamesI ConDeclGADT {con_names = names} = names
-getConNamesI (XConDecl nec) = noExtCon nec
 
 hsImplicitBodyI :: HsImplicitBndrs DocNameI thing -> thing
 hsImplicitBodyI (HsIB { hsib_body = body }) = body
-hsImplicitBodyI (XHsImplicitBndrs nec) = noExtCon nec
 
 hsSigTypeI :: LHsSigType DocNameI -> LHsType DocNameI
 hsSigTypeI = hsImplicitBodyI
@@ -216,7 +207,6 @@ getGADTConType (ConDeclGADT { con_forall = L _ has_forall
 
 getGADTConType (ConDeclH98 {}) = panic "getGADTConType"
   -- Should only be called on ConDeclGADT
-getGADTConType (XConDecl nec) = noExtCon nec
 
 getMainDeclBinderI :: HsDecl DocNameI -> [IdP DocNameI]
 getMainDeclBinderI (TyClD _ d) = [tcdNameI d]
@@ -231,14 +221,12 @@ getMainDeclBinderI _ = []
 
 familyDeclLNameI :: FamilyDecl DocNameI -> Located DocName
 familyDeclLNameI (FamilyDecl { fdLName = n }) = n
-familyDeclLNameI (XFamilyDecl nec) = noExtCon nec
 
 tyClDeclLNameI :: TyClDecl DocNameI -> Located DocName
 tyClDeclLNameI (FamDecl { tcdFam = fd })     = familyDeclLNameI fd
 tyClDeclLNameI (SynDecl { tcdLName = ln })   = ln
 tyClDeclLNameI (DataDecl { tcdLName = ln })  = ln
 tyClDeclLNameI (ClassDecl { tcdLName = ln }) = ln
-tyClDeclLNameI (XTyClDecl nec) = noExtCon nec
 
 tcdNameI :: TyClDecl DocNameI -> DocName
 tcdNameI = unLoc . tyClDeclLNameI
@@ -274,7 +262,6 @@ getGADTConTypeG (ConDeclGADT { con_forall = L _ has_forall
 
 getGADTConTypeG (ConDeclH98 {}) = panic "getGADTConTypeG"
   -- Should only be called on ConDeclGADT
-getGADTConTypeG (XConDecl nec) = noExtCon nec
 
 
 -------------------------------------------------------------------------------
diff --git a/haddock-api/src/Haddock/Interface/Rename.hs b/haddock-api/src/Haddock/Interface/Rename.hs
index 47aeb31a..a4dda417 100644
--- a/haddock-api/src/Haddock/Interface/Rename.hs
+++ b/haddock-api/src/Haddock/Interface/Rename.hs
@@ -211,7 +211,6 @@ renameFamilyResultSig (L loc (KindSig _ ki))
 renameFamilyResultSig (L loc (TyVarSig _ bndr))
     = do { bndr' <- renameLTyVarBndr bndr
          ; return (L loc (TyVarSig noExtField bndr')) }
-renameFamilyResultSig (L _ (XFamilyResultSig nec)) = noExtCon nec
 
 renameInjectivityAnn :: LInjectivityAnn GhcRn -> RnM (LInjectivityAnn DocNameI)
 renameInjectivityAnn (L loc (InjectivityAnn lhs rhs))
@@ -305,7 +304,6 @@ renameLHsQTyVars (HsQTvs { hsq_explicit = tvs })
   = do { tvs' <- mapM renameLTyVarBndr tvs
        ; return (HsQTvs { hsq_ext = noExtField
                         , hsq_explicit = tvs' }) }
-renameLHsQTyVars (XLHsQTyVars nec) = noExtCon nec
 
 renameLTyVarBndr :: LHsTyVarBndr GhcRn -> RnM (LHsTyVarBndr DocNameI)
 renameLTyVarBndr (L loc (UserTyVar x (L l n)))
@@ -315,7 +313,6 @@ renameLTyVarBndr (L loc (KindedTyVar x (L lv n) kind))
   = do { n' <- rename n
        ; kind' <- renameLKind kind
        ; return (L loc (KindedTyVar x (L lv n') kind')) }
-renameLTyVarBndr (L _ (XTyVarBndr _ )) = error "haddock:renameLTyVarBndr"
 
 renameLContext :: Located [LHsType GhcRn] -> RnM (Located [LHsType DocNameI])
 renameLContext (L loc context) = do
@@ -406,7 +403,6 @@ renameTyClD d = case d of
                       , tcdFixity = fixity
                       , tcdFDs = lfundeps', tcdSigs = lsigs', tcdMeths= emptyBag
                       , tcdATs = ats', tcdATDefs = at_defs', tcdDocs = [], tcdCExt = noExtField })
-  XTyClDecl nec -> noExtCon nec
 
   where
     renameLFunDep (L loc (xs, ys)) = do
@@ -432,7 +428,6 @@ renameFamilyDecl (FamilyDecl { fdInfo = info, fdLName = lname
                        , fdFixity = fixity
                        , fdResultSig = result'
                        , fdInjectivityAnn = injectivity' })
-renameFamilyDecl (XFamilyDecl nec) = noExtCon nec
 
 
 renamePseudoFamilyDecl :: PseudoFamilyDecl GhcRn
@@ -462,7 +457,6 @@ renameDataDefn (HsDataDefn { dd_ND = nd, dd_ctxt = lcontext, dd_cType = cType
                        , dd_ND = nd, dd_ctxt = lcontext', dd_cType = cType
                        , dd_kindSig = k', dd_cons = cons'
                        , dd_derivs = noLoc [] })
-renameDataDefn (XHsDataDefn nec) = noExtCon nec
 
 renameCon :: ConDecl GhcRn -> RnM (ConDecl DocNameI)
 renameCon decl@(ConDeclH98 { con_name = lname, con_ex_tvs = ltyvars
@@ -490,7 +484,6 @@ renameCon decl@(ConDeclGADT { con_names = lnames, con_qvars = ltyvars
       return (decl { con_g_ext = noExtField, con_names = lnames', con_qvars = ltyvars'
                    , con_mb_cxt = lcontext', con_args = details'
                    , con_res_ty = res_ty', con_doc = mbldoc' })
-renameCon (XConDecl nec) = noExtCon nec
 
 renameDetails :: HsConDeclDetails GhcRn -> RnM (HsConDeclDetails DocNameI)
 renameDetails (RecCon (L l fields)) = do
@@ -508,13 +501,11 @@ renameConDeclFieldField (L l (ConDeclField _ names t doc)) = do
   t'   <- renameLType t
   doc' <- mapM renameLDocHsSyn doc
   return $ L l (ConDeclField noExtField names' t' doc')
-renameConDeclFieldField (L _ (XConDeclField nec)) = noExtCon nec
 
 renameLFieldOcc :: LFieldOcc GhcRn -> RnM (LFieldOcc DocNameI)
 renameLFieldOcc (L l (FieldOcc sel lbl)) = do
   sel' <- rename sel
   return $ L l (FieldOcc sel' lbl)
-renameLFieldOcc (L _ (XFieldOcc _)) = error "haddock:renameLFieldOcc"
 
 renameSig :: Sig GhcRn -> RnM (Sig DocNameI)
 renameSig sig = case sig of
@@ -549,7 +540,6 @@ renameForD (ForeignExport _ lname ltype x) = do
   lname' <- renameL lname
   ltype' <- renameLSigType ltype
   return (ForeignExport noExtField lname' ltype' x)
-renameForD (XForeignDecl nec) = noExtCon nec
 
 
 renameInstD :: InstDecl GhcRn -> RnM (InstDecl DocNameI)
@@ -562,7 +552,6 @@ renameInstD (TyFamInstD { tfid_inst = d }) = do
 renameInstD (DataFamInstD { dfid_inst = d }) = do
   d' <- renameDataFamInstD d
   return (DataFamInstD { dfid_ext = noExtField, dfid_inst = d' })
-renameInstD (XInstDecl nec) = noExtCon nec
 
 renameDerivD :: DerivDecl GhcRn -> RnM (DerivDecl DocNameI)
 renameDerivD (DerivDecl { deriv_type = ty
@@ -574,7 +563,6 @@ renameDerivD (DerivDecl { deriv_type = ty
                     , deriv_type = ty'
                     , deriv_strategy = strat'
                     , deriv_overlap_mode = omode })
-renameDerivD (XDerivDecl nec) = noExtCon nec
 
 renameDerivStrategy :: DerivStrategy GhcRn -> RnM (DerivStrategy DocNameI)
 renameDerivStrategy StockStrategy    = pure StockStrategy
@@ -593,7 +581,6 @@ renameClsInstD (ClsInstDecl { cid_overlap_mode = omode
                       , cid_poly_ty = ltype', cid_binds = emptyBag
                       , cid_sigs = []
                       , cid_tyfam_insts = lATs', cid_datafam_insts = lADTs' })
-renameClsInstD (XClsInstDecl nec) = noExtCon nec
 
 
 renameTyFamInstD :: TyFamInstDecl GhcRn -> RnM (TyFamInstDecl DocNameI)
@@ -621,7 +608,6 @@ renameTyFamInstEqn eqn
                             , feqn_pats   = pats'
                             , feqn_fixity = fixity
                             , feqn_rhs    = rhs' }) }
-    rename_ty_fam_eqn (XFamEqn nec) = noExtCon nec
 
 renameTyFamDefltD :: TyFamDefltDecl GhcRn -> RnM (TyFamDefltDecl DocNameI)
 renameTyFamDefltD = renameTyFamInstD
@@ -647,7 +633,6 @@ renameDataFamInstD (DataFamInstDecl { dfid_eqn = eqn })
                             , feqn_pats   = pats'
                             , feqn_fixity = fixity
                             , feqn_rhs    = defn' }) }
-    rename_data_fam_eqn (XFamEqn nec) = noExtCon nec
 
 renameImplicit :: (in_thing -> RnM out_thing)
                -> HsImplicitBndrs GhcRn in_thing
@@ -656,7 +641,6 @@ renameImplicit rn_thing (HsIB { hsib_body = thing })
   = do { thing' <- rn_thing thing
        ; return (HsIB { hsib_body = thing'
                       , hsib_ext = noExtField }) }
-renameImplicit _ (XHsImplicitBndrs nec) = noExtCon nec
 
 renameWc :: (in_thing -> RnM out_thing)
          -> HsWildCardBndrs GhcRn in_thing
@@ -665,7 +649,6 @@ renameWc rn_thing (HsWC { hswc_body = thing })
   = do { thing' <- rn_thing thing
        ; return (HsWC { hswc_body = thing'
                       , hswc_ext = noExtField }) }
-renameWc _ (XHsWildCardBndrs nec) = noExtCon nec
 
 renameDocInstance :: DocInstance GhcRn -> RnM (DocInstance DocNameI)
 renameDocInstance (inst, idoc, L l n, m) = do
diff --git a/haddock-api/src/Haddock/Interface/Specialize.hs b/haddock-api/src/Haddock/Interface/Specialize.hs
index 92ad33d3..d79b61d9 100644
--- a/haddock-api/src/Haddock/Interface/Specialize.hs
+++ b/haddock-api/src/Haddock/Interface/Specialize.hs
@@ -295,7 +295,6 @@ renameBinder :: HsTyVarBndr GhcRn -> Rename (IdP GhcRn) (HsTyVarBndr GhcRn)
 renameBinder (UserTyVar x lname) = UserTyVar x <$> located renameName lname
 renameBinder (KindedTyVar x lname lkind) =
   KindedTyVar x <$> located renameName lname <*> located renameType lkind
-renameBinder (XTyVarBndr _) = error "haddock:renameBinder"
 
 -- | Core renaming logic.
 renameName :: (Eq name, SetName name) => name -> Rename name name
diff --git a/haddock-api/src/Haddock/Types.hs b/haddock-api/src/Haddock/Types.hs
index f30071b7..1a0b2c79 100644
--- a/haddock-api/src/Haddock/Types.hs
+++ b/haddock-api/src/Haddock/Types.hs
@@ -378,13 +378,12 @@ mkPseudoFamilyDecl (FamilyDecl { .. }) = PseudoFamilyDecl
     , pfdKindSig = fdResultSig
     }
   where
+    mkType :: HsTyVarBndr (GhcPass p) -> HsType (GhcPass p)
     mkType (KindedTyVar _ (L loc name) lkind) =
         HsKindSig noExtField tvar lkind
       where
         tvar = L loc (HsTyVar noExtField NotPromoted (L loc name))
     mkType (UserTyVar _ name) = HsTyVar noExtField NotPromoted name
-    mkType (XTyVarBndr nec) = noExtCon nec
-mkPseudoFamilyDecl (XFamilyDecl nec) = noExtCon nec
 
 
 -- | An instance head that may have documentation and a source location.
diff --git a/haddock-api/src/Haddock/Utils.hs b/haddock-api/src/Haddock/Utils.hs
index a71c7504..df14eeb2 100644
--- a/haddock-api/src/Haddock/Utils.hs
+++ b/haddock-api/src/Haddock/Utils.hs
@@ -181,7 +181,6 @@ restrictDataDefn names defn@(HsDataDefn { dd_ND = new_or_data, dd_cons = cons })
       []    -> defn { dd_ND = DataType, dd_cons = [] }
       [con] -> defn { dd_cons = [con] }
       _ -> error "Should not happen"
-restrictDataDefn _ (XHsDataDefn _) = error "restrictDataDefn"
 
 restrictCons :: [Name] -> [LConDecl GhcRn] -> [LConDecl GhcRn]
 restrictCons names decls = [ L p d | L p (Just d) <- map (fmap keep) decls ]
@@ -201,7 +200,6 @@ restrictCons names decls = [ L p d | L p (Just d) <- map (fmap keep) decls ]
         field_avail :: LConDeclField GhcRn -> Bool
         field_avail (L _ (ConDeclField _ fs _ _))
             = all (\f -> extFieldOcc (unLoc f) `elem` names) fs
-        field_avail (L _ (XConDeclField nec)) = noExtCon nec
         field_types flds = [ t | ConDeclField _ _ t _ <- flds ]
 
     keep _ = Nothing