Merge branch 'ghc-head' with 'ghc-8.4'

6 files changed, 710 insertions, 547 deletions

diff --git a/haddock-api/src/Haddock/Backends/Hoogle.hs b/haddock-api/src/Haddock/Backends/Hoogle.hs
index e7ce9d30..9a31428f 100644
--- a/haddock-api/src/Haddock/Backends/Hoogle.hs
+++ b/haddock-api/src/Haddock/Backends/Hoogle.hs
@@ -1,4 +1,5 @@
 {-# LANGUAGE FlexibleContexts #-}
+{-# LANGUAGE TypeFamilies #-}
 -----------------------------------------------------------------------------
 -- |
 -- Module      :  Haddock.Backends.Hoogle
@@ -73,21 +74,21 @@ dropHsDocTy :: HsType a -> HsType a
 dropHsDocTy = f
     where
         g (L src x) = L src (f x)
-        f (HsForAllTy a e) = HsForAllTy a (g e)
-        f (HsQualTy a e) = HsQualTy a (g e)
-        f (HsBangTy a b) = HsBangTy a (g b)
-        f (HsAppTy a b) = HsAppTy (g a) (g b)
-        f (HsFunTy a b) = HsFunTy (g a) (g b)
-        f (HsListTy a) = HsListTy (g a)
-        f (HsPArrTy a) = HsPArrTy (g a)
-        f (HsTupleTy a b) = HsTupleTy a (map g b)
-        f (HsOpTy a b c) = HsOpTy (g a) b (g c)
-        f (HsParTy a) = HsParTy (g a)
-        f (HsKindSig a b) = HsKindSig (g a) b
-        f (HsDocTy a _) = f $ unL a
+        f (HsForAllTy x a e) = HsForAllTy x a (g e)
+        f (HsQualTy x a e) = HsQualTy x a (g e)
+        f (HsBangTy x a b) = HsBangTy x a (g b)
+        f (HsAppTy x a b) = HsAppTy x (g a) (g b)
+        f (HsFunTy x a b) = HsFunTy x (g a) (g b)
+        f (HsListTy x a) = HsListTy x (g a)
+        f (HsPArrTy x a) = HsPArrTy x (g a)
+        f (HsTupleTy x a b) = HsTupleTy x a (map g b)
+        f (HsOpTy x a b c) = HsOpTy x (g a) b (g c)
+        f (HsParTy x a) = HsParTy x (g a)
+        f (HsKindSig x a b) = HsKindSig x (g a) b
+        f (HsDocTy _ a _) = f $ unL a
         f x = x
 
-outHsType :: (SourceTextX a, OutputableBndrId a)
+outHsType :: (a ~ GhcPass p, OutputableBndrId a)
           => DynFlags -> HsType a -> String
 outHsType dflags = out dflags . dropHsDocTy
 
@@ -125,20 +126,20 @@ ppExport dflags ExportDecl { expItemDecl    = L _ decl
                            , expItemFixities = fixities
                            } = ppDocumentation dflags dc ++ f decl
     where
-        f (TyClD d@DataDecl{})  = ppData dflags d subdocs
-        f (TyClD d@SynDecl{})   = ppSynonym dflags d
-        f (TyClD d@ClassDecl{}) = ppClass dflags d subdocs
-        f (TyClD (FamDecl d))   = ppFam dflags d
-        f (ForD (ForeignImport name typ _ _)) = [pp_sig dflags [name] (hsSigType typ)]
-        f (ForD (ForeignExport name typ _ _)) = [pp_sig dflags [name] (hsSigType typ)]
-        f (SigD sig) = ppSig dflags sig ++ ppFixities
+        f (TyClD _ d@DataDecl{})  = ppData dflags d subdocs
+        f (TyClD _ d@SynDecl{})   = ppSynonym dflags d
+        f (TyClD _ d@ClassDecl{}) = ppClass dflags d subdocs
+        f (TyClD _ (FamDecl _ d)) = ppFam dflags d
+        f (ForD _ (ForeignImport _ name typ _)) = [pp_sig dflags [name] (hsSigType typ)]
+        f (ForD _ (ForeignExport _ name typ _)) = [pp_sig dflags [name] (hsSigType typ)]
+        f (SigD _ sig) = ppSig dflags sig ++ ppFixities
         f _ = []
 
         ppFixities = concatMap (ppFixity dflags) fixities
 ppExport _ _ = []
 
 ppSigWithDoc :: DynFlags -> Sig GhcRn -> [(Name, DocForDecl Name)] -> [String]
-ppSigWithDoc dflags (TypeSig names sig) subdocs
+ppSigWithDoc dflags (TypeSig _ names sig) subdocs
     = concatMap mkDocSig names
     where
         mkDocSig n = mkSubdoc dflags n subdocs [pp_sig dflags [n] (hsSigWcType sig)]
@@ -189,7 +190,7 @@ ppClass dflags decl subdocs =
             , tcdTyVars = feqn_pats tfe
             , tcdFixity = feqn_fixity tfe
             , tcdRhs    = feqn_rhs tfe
-            , tcdFVs    = emptyNameSet
+            , tcdSExt   = emptyNameSet
             }
 
 ppFam :: DynFlags -> FamilyDecl GhcRn -> [String]
@@ -241,17 +242,17 @@ lookupCon dflags subdocs (L _ name) = case lookup name subdocs of
 ppCtor :: DynFlags -> TyClDecl GhcRn -> [(Name, DocForDecl Name)] -> ConDecl GhcRn -> [String]
 ppCtor dflags dat subdocs con@ConDeclH98 {}
   -- AZ:TODO get rid of the concatMap
-   = concatMap (lookupCon dflags subdocs) [con_name con] ++ f (getConDetails con)
+   = concatMap (lookupCon dflags subdocs) [con_name con] ++ f (getConArgs con)
     where
         f (PrefixCon args) = [typeSig name $ args ++ [resType]]
         f (InfixCon a1 a2) = f $ PrefixCon [a1,a2]
         f (RecCon (L _ recs)) = f (PrefixCon $ map cd_fld_type (map unLoc recs)) ++ concat
-                          [(concatMap (lookupCon dflags subdocs . noLoc . selectorFieldOcc . unLoc) (cd_fld_names r)) ++
-                           [out dflags (map (selectorFieldOcc . unLoc) $ cd_fld_names r) `typeSig` [resType, cd_fld_type r]]
+                          [(concatMap (lookupCon dflags subdocs . noLoc . extFieldOcc . unLoc) (cd_fld_names r)) ++
+                           [out dflags (map (extFieldOcc . unLoc) $ cd_fld_names r) `typeSig` [resType, cd_fld_type r]]
                           | r <- map unLoc recs]
 
-        funs = foldr1 (\x y -> reL $ HsFunTy x y)
-        apps = foldl1 (\x y -> reL $ HsAppTy x y)
+        funs = foldr1 (\x y -> reL $ HsFunTy NoExt x y)
+        apps = foldl1 (\x y -> reL $ HsAppTy NoExt x y)
 
         typeSig nm flds = operator nm ++ " :: " ++ outHsType dflags (unL $ funs flds)
 
@@ -259,20 +260,20 @@ ppCtor dflags dat subdocs con@ConDeclH98 {}
         -- docs for con_names on why it is a list to begin with.
         name = commaSeparate dflags . map unL $ getConNames con
 
-        resType = apps $ map (reL . HsTyVar NotPromoted . reL) $
-                        (tcdName dat) : [hsTyVarName v | L _ v@(UserTyVar _) <- hsQTvExplicit $ tyClDeclTyVars dat]
+        resType = apps $ map (reL . HsTyVar NoExt NotPromoted . reL) $
+                        (tcdName dat) : [hsTyVarName v | L _ v@(UserTyVar _ _) <- hsQTvExplicit $ tyClDeclTyVars dat]
 
-ppCtor dflags _dat subdocs con@ConDeclGADT {}
+ppCtor dflags _dat subdocs con@(ConDeclGADT { })
    = concatMap (lookupCon dflags subdocs) (getConNames con) ++ f
     where
-        f = [typeSig name (hsib_body $ con_type con)]
+        f = [typeSig name (getGADTConTypeG con)]
 
         typeSig nm ty = operator nm ++ " :: " ++ outHsType dflags (unL ty)
         name = out dflags $ map unL $ getConNames con
-
+ppCtor _ _ _ XConDecl {} = panic "haddock:ppCtor"
 
 ppFixity :: DynFlags -> (Name, Fixity) -> [String]
-ppFixity dflags (name, fixity) = [out dflags ((FixitySig [noLoc name] fixity) :: FixitySig GhcRn)]
+ppFixity dflags (name, fixity) = [out dflags ((FixitySig noExt [noLoc name] fixity) :: FixitySig GhcRn)]
 
 
 ---------------------------------------------------------------------
diff --git a/haddock-api/src/Haddock/Backends/Hyperlinker/Ast.hs b/haddock-api/src/Haddock/Backends/Hyperlinker/Ast.hs
index c4a9091f..220a59fe 100644
--- a/haddock-api/src/Haddock/Backends/Hyperlinker/Ast.hs
+++ b/haddock-api/src/Haddock/Backends/Hyperlinker/Ast.hs
@@ -13,6 +13,7 @@ import Haddock.Backends.Hyperlinker.Types
 
 import qualified GHC
 import qualified SrcLoc
+import qualified Outputable as GHC
 
 import Control.Applicative
 import Control.Monad (guard)
@@ -79,9 +80,9 @@ variables =
     everythingInRenamedSource (var `Syb.combine` rec)
   where
     var term = case cast term of
-        (Just ((GHC.L sspan (GHC.HsVar name)) :: GHC.LHsExpr GHC.GhcRn)) ->
+        (Just ((GHC.L sspan (GHC.HsVar _ name)) :: GHC.LHsExpr GHC.GhcRn)) ->
             pure (sspan, RtkVar (GHC.unLoc name))
-        (Just (GHC.L _ (GHC.RecordCon (GHC.L sspan name) _ _ _))) ->
+        (Just (GHC.L _ (GHC.RecordCon _ (GHC.L sspan name) _))) ->
             pure (sspan, RtkVar name)
         _ -> empty
     rec term = case cast term of
@@ -95,9 +96,9 @@ types = everythingInRenamedSource ty
   where
     ty :: forall a. Data a => a -> [(GHC.SrcSpan, TokenDetails)]
     ty term = case cast term of
-        (Just ((GHC.L sspan (GHC.HsTyVar _ name)) :: GHC.LHsType GHC.GhcRn)) ->
+        (Just ((GHC.L sspan (GHC.HsTyVar _ _ name)) :: GHC.LHsType GHC.GhcRn)) ->
             pure (sspan, RtkType (GHC.unLoc name))
-        (Just ((GHC.L sspan (GHC.HsOpTy l name r)) :: GHC.LHsType GHC.GhcRn)) ->
+        (Just ((GHC.L sspan (GHC.HsOpTy _ l name r)) :: GHC.LHsType GHC.GhcRn)) ->
             (sspan, RtkType (GHC.unLoc name)):(ty l ++ ty r)
         _ -> empty
 
@@ -112,20 +113,20 @@ binds = everythingInRenamedSource
       (fun `Syb.combine` pat `Syb.combine` tvar)
   where
     fun term = case cast term of
-        (Just (GHC.FunBind (GHC.L sspan name) _ _ _ _ :: GHC.HsBind GHC.GhcRn)) ->
+        (Just (GHC.FunBind _ (GHC.L sspan name) _ _ _ :: GHC.HsBind GHC.GhcRn)) ->
             pure (sspan, RtkBind name)
-        (Just (GHC.PatSynBind (GHC.PSB (GHC.L sspan name) _ args _ _))) ->
+        (Just (GHC.PatSynBind _ (GHC.PSB _ (GHC.L sspan name) args _ _))) ->
             pure (sspan, RtkBind name) ++ everythingInRenamedSource patsyn_binds args
         _ -> empty
     patsyn_binds term = case cast term of
         (Just (GHC.L sspan (name :: GHC.Name))) -> pure (sspan, RtkVar name)
         _ -> empty
     pat term = case cast term of
-        (Just ((GHC.L sspan (GHC.VarPat name)) :: GHC.LPat GHC.GhcRn)) ->
+        (Just ((GHC.L sspan (GHC.VarPat _ name)) :: GHC.LPat GHC.GhcRn)) ->
             pure (sspan, RtkBind (GHC.unLoc name))
         (Just (GHC.L _ (GHC.ConPatIn (GHC.L sspan name) recs))) ->
             [(sspan, RtkVar name)] ++ everythingInRenamedSource rec recs
-        (Just (GHC.L _ (GHC.AsPat (GHC.L sspan name) _))) ->
+        (Just (GHC.L _ (GHC.AsPat _ (GHC.L sspan name) _))) ->
             pure (sspan, RtkBind name)
         _ -> empty
     rec term = case cast term of
@@ -133,9 +134,9 @@ binds = everythingInRenamedSource
             pure (sspan, RtkVar name)
         _ -> empty
     tvar term = case cast term of
-        (Just ((GHC.L sspan (GHC.UserTyVar name)) :: GHC.LHsTyVarBndr GHC.GhcRn)) ->
+        (Just ((GHC.L sspan (GHC.UserTyVar _ name)) :: GHC.LHsTyVarBndr GHC.GhcRn)) ->
             pure (sspan, RtkBind (GHC.unLoc name))
-        (Just (GHC.L _ (GHC.KindedTyVar (GHC.L sspan name) _))) ->
+        (Just (GHC.L _ (GHC.KindedTyVar _ (GHC.L sspan name) _))) ->
             pure (sspan, RtkBind name)
         _ -> empty
 
@@ -150,16 +151,17 @@ decls (group, _, _, _) = concatMap ($ group)
   where
     typ (GHC.L _ t) = case t of
         GHC.DataDecl { tcdLName = name } -> pure . decl $ name
-        GHC.SynDecl name _ _ _ _ -> pure . decl $ name
-        GHC.FamDecl fam -> pure . decl $ GHC.fdLName fam
+        GHC.SynDecl _ name _ _ _ -> pure . decl $ name
+        GHC.FamDecl _ fam -> pure . decl $ GHC.fdLName fam
         GHC.ClassDecl{..} ->
           [decl tcdLName]
             ++ concatMap sig tcdSigs
             ++ concatMap tyfam tcdATs
+        GHC.XTyClDecl {} -> GHC.panic "haddock:decls"
     fun term = case cast term of
-        (Just (GHC.FunBind (GHC.L sspan name) _ _ _ _ :: GHC.HsBind GHC.GhcRn))
+        (Just (GHC.FunBind _ (GHC.L sspan name) _ _ _ :: GHC.HsBind GHC.GhcRn))
             | GHC.isExternalName name -> pure (sspan, RtkDecl name)
-        (Just (GHC.PatSynBind (GHC.PSB (GHC.L sspan name) _ _ _ _)))
+        (Just (GHC.PatSynBind _ (GHC.PSB _ (GHC.L sspan name) _ _ _)))
             | GHC.isExternalName name -> pure (sspan, RtkDecl name)
         _ -> empty
     con term = case cast term of
@@ -168,24 +170,24 @@ decls (group, _, _, _) = concatMap ($ group)
               ++ everythingInRenamedSource fld cdcl
         Nothing -> empty
     ins term = case cast term of
-        (Just ((GHC.DataFamInstD (GHC.DataFamInstDecl eqn))
+        (Just ((GHC.DataFamInstD _ (GHC.DataFamInstDecl eqn))
                 :: GHC.InstDecl GHC.GhcRn))
           -> pure . tyref $ GHC.feqn_tycon $ GHC.hsib_body eqn
-        (Just (GHC.TyFamInstD (GHC.TyFamInstDecl eqn))) ->
+        (Just (GHC.TyFamInstD _ (GHC.TyFamInstDecl eqn))) ->
             pure . tyref $ GHC.feqn_tycon $ GHC.hsib_body eqn
         _ -> empty
     fld term = case cast term of
         Just (field :: GHC.ConDeclField GHC.GhcRn)
-          -> map (decl . fmap GHC.selectorFieldOcc) $ GHC.cd_fld_names field
+          -> map (decl . fmap GHC.extFieldOcc) $ GHC.cd_fld_names field
         Nothing -> empty
     fix term = case cast term of
-        Just ((GHC.FixitySig names _) :: GHC.FixitySig GHC.GhcRn)
+        Just ((GHC.FixitySig _ names _) :: GHC.FixitySig GHC.GhcRn)
           -> map (\(GHC.L sspan x) -> (sspan, RtkVar x)) names
         Nothing -> empty
     tyfam (GHC.L _ (GHC.FamilyDecl{..})) = [decl fdLName]
-    sig (GHC.L _ (GHC.TypeSig names _)) = map decl names
-    sig (GHC.L _ (GHC.PatSynSig names _)) = map decl names
-    sig (GHC.L _ (GHC.ClassOpSig _ names _)) = map decl names
+    sig (GHC.L _ (GHC.TypeSig _ names _)) = map decl names
+    sig (GHC.L _ (GHC.PatSynSig _ names _)) = map decl names
+    sig (GHC.L _ (GHC.ClassOpSig _ _ names _)) = map decl names
     sig _ = []
     decl (GHC.L sspan name) = (sspan, RtkDecl name)
     tyref (GHC.L sspan name) = (sspan, RtkType name)
@@ -199,12 +201,12 @@ imports src@(_, imps, _, _) =
     everythingInRenamedSource ie src ++ mapMaybe (imp . GHC.unLoc) imps
   where
     ie term = case cast term of
-        (Just ((GHC.IEVar v) :: GHC.IE GHC.GhcRn)) -> pure $ var $ GHC.ieLWrappedName v
-        (Just (GHC.IEThingAbs t)) -> pure $ typ $ GHC.ieLWrappedName t
-        (Just (GHC.IEThingAll t)) -> pure $ typ $ GHC.ieLWrappedName t
-        (Just (GHC.IEThingWith t _ vs _fls)) ->
+        (Just ((GHC.IEVar _ v) :: GHC.IE GHC.GhcRn)) -> pure $ var $ GHC.ieLWrappedName v
+        (Just (GHC.IEThingAbs _ t)) -> pure $ typ $ GHC.ieLWrappedName t
+        (Just (GHC.IEThingAll _ t)) -> pure $ typ $ GHC.ieLWrappedName t
+        (Just (GHC.IEThingWith _ t _ vs _fls)) ->
           [typ $ GHC.ieLWrappedName t] ++ map (var . GHC.ieLWrappedName) vs
-        (Just (GHC.IEModuleContents m)) -> pure $ modu m
+        (Just (GHC.IEModuleContents _ m)) -> pure $ modu m
         _ -> empty
     typ (GHC.L sspan name) = (sspan, RtkType name)
     var (GHC.L sspan name) = (sspan, RtkVar name)
diff --git a/haddock-api/src/Haddock/Backends/LaTeX.hs b/haddock-api/src/Haddock/Backends/LaTeX.hs
index 38fccf0c..d06e85d1 100644
--- a/haddock-api/src/Haddock/Backends/LaTeX.hs
+++ b/haddock-api/src/Haddock/Backends/LaTeX.hs
@@ -179,13 +179,14 @@ string_txt (PStr s1) s2 = unpackFS s1 ++ s2
 string_txt (ZStr s1) s2 = zString s1 ++ s2
 string_txt (LStr s1 _) s2 = unpackLitString s1 ++ s2
 
-
+-- | Prints out an entry in a module export list.
 exportListItem :: ExportItem DocNameI -> LaTeX
 exportListItem ExportDecl { expItemDecl = decl, expItemSubDocs = subdocs }
-  = sep (punctuate comma . map ppDocBinder $ declNames decl) <>
-     case subdocs of
-       [] -> empty
-       _  -> parens (sep (punctuate comma (map (ppDocBinder . fst) subdocs)))
+  = let (leader, names) = declNames decl
+    in sep (punctuate comma [ leader <+> ppDocBinder name | name <- names ]) <>
+         case subdocs of
+           [] -> empty
+           _  -> parens (sep (punctuate comma (map (ppDocBinder . fst) subdocs)))
 exportListItem (ExportNoDecl y [])
   = ppDocBinder y
 exportListItem (ExportNoDecl y subs)
@@ -215,7 +216,7 @@ processExports (e : es) =
 
 
 isSimpleSig :: ExportItem DocNameI -> Maybe ([DocName], HsType DocNameI)
-isSimpleSig ExportDecl { expItemDecl = L _ (SigD (TypeSig lnames t))
+isSimpleSig ExportDecl { expItemDecl = L _ (SigD _ (TypeSig _ lnames t))
                        , expItemMbDoc = (Documentation Nothing Nothing, argDocs) }
   | Map.null argDocs = Just (map unLoc lnames, unLoc (hsSigWcType t))
 isSimpleSig _ = Nothing
@@ -249,13 +250,17 @@ ppDocGroup lev doc = sec lev <> braces doc
         sec _ = text "\\paragraph"
 
 
-declNames :: LHsDecl DocNameI -> [DocName]
+-- | Given a declaration, extract out the names being declared
+declNames :: LHsDecl DocNameI
+          -> ( LaTeX           -- ^ to print before each name in an export list
+             , [DocName]       -- ^ names being declared
+             )
 declNames (L _ decl) = case decl of
-  TyClD d  -> [tcdName d]
-  SigD (TypeSig lnames _ ) -> map unLoc lnames
-  SigD (PatSynSig lnames _) -> map unLoc lnames
-  ForD (ForeignImport (L _ n) _ _ _) -> [n]
-  ForD (ForeignExport (L _ n) _ _ _) -> [n]
+  TyClD _ d  -> (empty, [tcdName d])
+  SigD _ (TypeSig _ lnames _ ) -> (empty, map unLoc lnames)
+  SigD _ (PatSynSig _ lnames _) -> (text "pattern", map unLoc lnames)
+  ForD _ (ForeignImport _ (L _ n) _ _) -> (empty, [n])
+  ForD _ (ForeignExport _ (L _ n) _ _) -> (empty, [n])
   _ -> error "declaration not supported by declNames"
 
 
@@ -278,47 +283,44 @@ moduleBasename mdl = map (\c -> if c == '.' then '-' else c)
 -- * Decls
 -------------------------------------------------------------------------------
 
-
-ppDecl :: LHsDecl DocNameI
-       -> [(HsDecl DocNameI, DocForDecl DocName)]
-       -> DocForDecl DocName
-       -> [DocInstance DocNameI]
-       -> [(DocName, DocForDecl DocName)]
-       -> [(DocName, Fixity)]
+-- | Pretty print a declaration
+ppDecl :: LHsDecl DocNameI                         -- ^ decl to print
+       -> [(HsDecl DocNameI, DocForDecl DocName)]  -- ^ all pattern decls
+       -> DocForDecl DocName                       -- ^ documentation for decl
+       -> [DocInstance DocNameI]                   -- ^ all instances
+       -> [(DocName, DocForDecl DocName)]          -- ^ all subdocs
+       -> [(DocName, Fixity)]                      -- ^ all fixities
        -> LaTeX
 
-ppDecl (L loc decl) pats (doc, fnArgsDoc) instances subdocs _fixities = case decl of
-  TyClD d@(FamDecl {})          -> ppTyFam False loc doc d unicode
-  TyClD d@(DataDecl {})
-                                -> ppDataDecl pats instances subdocs loc (Just doc) d unicode
-  TyClD d@(SynDecl {})          -> ppTySyn loc (doc, fnArgsDoc) d unicode
+ppDecl decl pats (doc, fnArgsDoc) instances subdocs _fxts = case unLoc decl of
+  TyClD _ d@FamDecl {}         -> ppTyFam False doc d unicode
+  TyClD _ d@DataDecl {}        -> ppDataDecl pats instances subdocs (Just doc) d unicode
+  TyClD _ d@SynDecl {}         -> ppTySyn (doc, fnArgsDoc) d unicode
 -- Family instances happen via FamInst now
---  TyClD d@(TySynonym {})
+--  TyClD _ d@TySynonym{}
 --    | Just _  <- tcdTyPats d    -> ppTyInst False loc doc d unicode
 -- Family instances happen via FamInst now
-  TyClD d@(ClassDecl {})    -> ppClassDecl instances loc doc subdocs d unicode
-  SigD (TypeSig lnames t)   -> ppFunSig loc (doc, fnArgsDoc) (map unLoc lnames)
-                                        (hsSigWcType t) unicode
-  SigD (PatSynSig lnames ty) ->
-      ppLPatSig loc (doc, fnArgsDoc) (map unLoc lnames) ty unicode
-  ForD d                         -> ppFor loc (doc, fnArgsDoc) d unicode
-  InstD _                        -> empty
-  DerivD _                       -> empty
+  TyClD _ d@ClassDecl{}          -> ppClassDecl instances doc subdocs d unicode
+  SigD _ (TypeSig _ lnames ty)   -> ppFunSig (doc, fnArgsDoc) (map unLoc lnames) (hsSigWcType ty) unicode
+  SigD _ (PatSynSig _ lnames ty) -> ppLPatSig (doc, fnArgsDoc) (map unLoc lnames) ty unicode
+  ForD _ d                       -> ppFor (doc, fnArgsDoc) d unicode
+  InstD _ _                      -> empty
+  DerivD _ _                     -> empty
   _                              -> error "declaration not supported by ppDecl"
   where
     unicode = False
 
 
-ppTyFam :: Bool -> SrcSpan -> Documentation DocName ->
+ppTyFam :: Bool -> Documentation DocName ->
               TyClDecl DocNameI -> Bool -> LaTeX
-ppTyFam _ _ _ _ _ =
+ppTyFam _ _ _ _ =
   error "type family declarations are currently not supported by --latex"
 
 
-ppFor :: SrcSpan -> DocForDecl DocName -> ForeignDecl DocNameI -> Bool -> LaTeX
-ppFor loc doc (ForeignImport (L _ name) typ _ _) unicode =
-  ppFunSig loc doc [name] (hsSigType typ) unicode
-ppFor _ _ _ _ = error "ppFor error in Haddock.Backends.LaTeX"
+ppFor :: DocForDecl DocName -> ForeignDecl DocNameI -> Bool -> LaTeX
+ppFor doc (ForeignImport _ (L _ name) typ _) unicode =
+  ppFunSig doc [name] (hsSigType typ) unicode
+ppFor _ _ _ = error "ppFor error in Haddock.Backends.LaTeX"
 --  error "foreign declarations are currently not supported by --latex"
 
 
@@ -328,18 +330,18 @@ ppFor _ _ _ _ = error "ppFor error in Haddock.Backends.LaTeX"
 
 
 -- we skip type patterns for now
-ppTySyn :: SrcSpan -> DocForDecl DocName -> TyClDecl DocNameI -> Bool -> LaTeX
+ppTySyn :: DocForDecl DocName -> TyClDecl DocNameI -> Bool -> LaTeX
 
-ppTySyn loc doc (SynDecl { tcdLName = L _ name, tcdTyVars = ltyvars
+ppTySyn doc (SynDecl { tcdLName = L _ name, tcdTyVars = ltyvars
                          , tcdRhs = ltype }) unicode
-  = ppTypeOrFunSig loc [name] (unLoc ltype) doc (full, hdr, char '=') unicode
+  = ppTypeOrFunSig (unLoc ltype) doc (full, hdr, char '=') unicode
   where
     hdr  = hsep (keyword "type"
                  : ppDocBinder name
                  : map ppSymName (tyvarNames ltyvars))
     full = hdr <+> char '=' <+> ppLType unicode ltype
 
-ppTySyn _ _ _ _ = error "declaration not supported by ppTySyn"
+ppTySyn _ _ _ = error "declaration not supported by ppTySyn"
 
 
 -------------------------------------------------------------------------------
@@ -347,61 +349,98 @@ ppTySyn _ _ _ _ = error "declaration not supported by ppTySyn"
 -------------------------------------------------------------------------------
 
 
-ppFunSig :: SrcSpan -> DocForDecl DocName -> [DocName] -> LHsType DocNameI
+ppFunSig :: DocForDecl DocName -> [DocName] -> LHsType DocNameI
          -> Bool -> LaTeX
-ppFunSig loc doc docnames (L _ typ) unicode =
-  ppTypeOrFunSig loc docnames typ doc
+ppFunSig doc docnames (L _ typ) unicode =
+  ppTypeOrFunSig typ doc
     ( ppTypeSig names typ False
     , hsep . punctuate comma $ map ppSymName names
-    , dcolon unicode)
+    , dcolon unicode
+    )
     unicode
  where
    names = map getName docnames
 
-ppLPatSig :: SrcSpan -> DocForDecl DocName -> [DocName]
-          -> LHsSigType DocNameI
-          -> Bool -> LaTeX
-ppLPatSig _loc (doc, _argDocs) docnames ty unicode
-  = declWithDoc pref1 (documentationToLaTeX doc)
+-- | Pretty-print a pattern synonym
+ppLPatSig :: DocForDecl DocName  -- ^ documentation
+          -> [DocName]           -- ^ pattern names in the pattern signature
+          -> LHsSigType DocNameI -- ^ type of the pattern synonym
+          -> Bool                -- ^ unicode
+          -> LaTeX
+ppLPatSig doc docnames ty unicode
+  = ppTypeOrFunSig typ doc
+      ( keyword "pattern" <+> ppTypeSig names typ False
+      , keyword "pattern" <+> (hsep . punctuate comma $ map ppSymName names)
+      , dcolon unicode
+      )
+      unicode
   where
-    pref1 = hsep [ keyword "pattern"
-                 , hsep $ punctuate comma $ map ppDocBinder docnames
-                 , dcolon unicode
-                 , ppLType unicode (hsSigType ty)
-                 ]
-
-ppTypeOrFunSig :: SrcSpan -> [DocName] -> HsType DocNameI
-               -> DocForDecl DocName -> (LaTeX, LaTeX, LaTeX)
-               -> Bool -> LaTeX
-ppTypeOrFunSig _ _ typ (doc, argDocs) (pref1, pref2, sep0)
-               unicode
-  | Map.null argDocs =
-      declWithDoc pref1 (documentationToLaTeX doc)
-  | otherwise        =
-      declWithDoc pref2 $ Just $
+    typ = unLoc (hsSigType ty)
+    names = map getName docnames
+
+-- | Pretty-print a type, adding documentation to the whole type and its
+-- arguments as needed.
+ppTypeOrFunSig :: HsType DocNameI
+               -> DocForDecl DocName  -- ^ documentation
+               -> ( LaTeX             -- ^ first-line (no-argument docs only)
+                  , LaTeX             -- ^ first-line (argument docs only)
+                  , LaTeX             -- ^ type prefix (argument docs only)
+                  )
+               -> Bool                -- ^ unicode
+               -> LaTeX
+ppTypeOrFunSig typ (doc, argDocs) (pref1, pref2, sep0) unicode
+  | Map.null argDocs = declWithDoc pref1 (documentationToLaTeX doc)
+  | otherwise        = declWithDoc pref2 $ Just $
         text "\\haddockbeginargs" $$
-        do_args 0 sep0 typ $$
+        vcat (map (uncurry (<->)) (ppSubSigLike unicode typ argDocs [] sep0)) $$
         text "\\end{tabulary}\\par" $$
         fromMaybe empty (documentationToLaTeX doc)
+
+-- This splits up a type signature along `->` and adds docs (when they exist)
+-- to the arguments. The output is a list of (leader/seperator, argument and
+-- its doc)
+ppSubSigLike :: Bool                  -- ^ unicode
+             -> HsType DocNameI       -- ^ type signature
+             -> FnArgsDoc DocName     -- ^ docs to add
+             -> [(DocName, DocForDecl DocName)] -- ^ all subdocs (useful when we have `HsRecTy`)
+             -> LaTeX                 -- ^ seperator (beginning of first line)
+             -> [(LaTeX, LaTeX)]      -- ^ arguments (leader/sep, type)
+ppSubSigLike unicode typ argDocs subdocs leader = do_args 0 leader typ
   where
-     do_largs n leader (L _ t) = do_args n leader t
-
-     arg_doc n = rDoc . fmap _doc $ Map.lookup n argDocs
-
-     do_args :: Int -> LaTeX -> HsType DocNameI -> LaTeX
-     do_args _n leader (HsForAllTy tvs ltype)
-       = decltt leader
-         <-> decltt (hsep (forallSymbol unicode : ppTyVars tvs ++ [dot]))
-         <+> ppLType unicode ltype
-     do_args n leader (HsQualTy lctxt ltype)
-       = decltt leader
-         <-> ppLContextNoArrow lctxt unicode <+> nl $$
-             do_largs n (darrow unicode) ltype
-     do_args n leader (HsFunTy lt r)
-       = decltt leader <-> decltt (ppLFunLhType unicode lt) <-> arg_doc n <+> nl $$
-         do_largs (n+1) (arrow unicode) r
-     do_args n leader t
-       = decltt leader <-> decltt (ppType unicode t) <-> arg_doc n <+> nl
+    do_largs n leader (L _ t) = do_args n leader t
+
+    arg_doc n = rDoc . fmap _doc $ Map.lookup n argDocs
+
+    do_args :: Int -> LaTeX -> HsType DocNameI -> [(LaTeX, LaTeX)]
+    do_args _n leader (HsForAllTy _ tvs ltype)
+      = [ ( decltt leader
+          , decltt (hsep (forallSymbol unicode : ppTyVars tvs ++ [dot]))
+              <+> ppLType unicode ltype
+          ) ]
+    do_args n leader (HsQualTy _ lctxt ltype)
+      = (decltt leader, ppLContextNoArrow lctxt unicode <+> nl)
+        : do_largs n (darrow unicode) ltype
+
+    do_args n leader (HsFunTy _ (L _ (HsRecTy _ fields)) r)
+      = [ (decltt ldr, latex <+> nl)
+        | (L _ field, ldr) <- zip fields (leader <+> gadtOpen : repeat gadtComma)
+        , let latex = ppSideBySideField subdocs unicode field
+        ]
+        ++ do_largs (n+1) (gadtEnd <+> arrow unicode) r
+    do_args n leader (HsFunTy _ lt r)
+      = (decltt leader, decltt (ppLFunLhType unicode lt) <-> arg_doc n <+> nl)
+        : do_largs (n+1) (arrow unicode) r
+    do_args n leader t
+      = [ (decltt leader, decltt (ppType unicode t) <-> arg_doc n <+> nl) ]
+
+    -- FIXME: this should be done more elegantly
+    --
+    -- We need 'gadtComma' and 'gadtEnd' to line up with the `{` from
+    -- 'gadtOpen', so we add 3 spaces to cover for `-> `/`:: ` (3 in unicode
+    -- mode since `->` and `::` are rendered as single characters.
+    gadtComma = hcat (replicate (if unicode then 3 else 4) (text "\\ ")) <> text ","
+    gadtEnd = hcat (replicate (if unicode then 3 else 4) (text "\\ ")) <> text "\\}"
+    gadtOpen = text "\\{"
 
 
 ppTypeSig :: [Name] -> HsType DocNameI  -> Bool -> LaTeX
@@ -483,10 +522,10 @@ ppFds fds unicode =
                            hsep (map (ppDocName . unLoc) vars2)
 
 
-ppClassDecl :: [DocInstance DocNameI] -> SrcSpan
+ppClassDecl :: [DocInstance DocNameI]
             -> Documentation DocName -> [(DocName, DocForDecl DocName)]
             -> TyClDecl DocNameI -> Bool -> LaTeX
-ppClassDecl instances loc doc subdocs
+ppClassDecl instances doc subdocs
   (ClassDecl { tcdCtxt = lctxt, tcdLName = lname, tcdTyVars = ltyvars, tcdFDs = lfds
              , tcdSigs = lsigs, tcdATs = ats, tcdATDefs = at_defs }) unicode
   = declWithDoc classheader (if null body then Nothing else Just (vcat body)) $$
@@ -508,15 +547,15 @@ ppClassDecl instances loc doc subdocs
 
     methodTable =
       text "\\haddockpremethods{}\\textbf{Methods}" $$
-      vcat  [ ppFunSig loc doc [name] (hsSigWcType typ) unicode
-            | L _ (TypeSig lnames typ) <- lsigs
+      vcat  [ ppFunSig doc [name] (hsSigWcType typ) unicode
+            | L _ (TypeSig _ lnames typ) <- lsigs
             , name <- map unLoc lnames
             , let doc = lookupAnySubdoc name subdocs
             ]
 
     instancesBit = ppDocInstances unicode instances
 
-ppClassDecl _ _ _ _ _ _ = error "declaration type not supported by ppShortClassDecl"
+ppClassDecl _ _ _ _ _ = error "declaration type not supported by ppShortClassDecl"
 
 ppDocInstances :: Bool -> [DocInstance DocNameI] -> LaTeX
 ppDocInstances _unicode [] = empty
@@ -565,15 +604,17 @@ lookupAnySubdoc n subdocs = case lookup n subdocs of
 -- * Data & newtype declarations
 -------------------------------------------------------------------------------
 
-
-ppDataDecl :: [(HsDecl DocNameI, DocForDecl DocName)] -> [DocInstance DocNameI] ->
-              [(DocName, DocForDecl DocName)] -> SrcSpan ->
-              Maybe (Documentation DocName) -> TyClDecl DocNameI -> Bool ->
-              LaTeX
-ppDataDecl pats instances subdocs _loc doc dataDecl unicode
-
-   =  declWithDoc (ppDataHeader dataDecl unicode <+> whereBit)
-                  (if null body then Nothing else Just (vcat body))
+-- | Pretty-print a data declaration
+ppDataDecl :: [(HsDecl DocNameI, DocForDecl DocName)] -- ^ relevant patterns
+           -> [DocInstance DocNameI]                  -- ^ relevant instances
+           -> [(DocName, DocForDecl DocName)]         -- ^ relevant decl docs
+           -> Maybe (Documentation DocName)           -- ^ this decl's docs
+           -> TyClDecl DocNameI                       -- ^ data decl to print
+           -> Bool                                    -- ^ unicode
+           -> LaTeX
+ppDataDecl pats instances subdocs doc dataDecl unicode =
+   declWithDoc (ppDataHeader dataDecl unicode <+> whereBit)
+               (if null body then Nothing else Just (vcat body))
    $$ instancesBit
 
   where
@@ -585,28 +626,26 @@ ppDataDecl pats instances subdocs _loc doc dataDecl unicode
     (whereBit, leaders)
       | null cons
       , null pats = (empty,[])
-      | null cons = (decltt (keyword "where"), repeat empty)
+      | null cons = (text "where", repeat empty)
       | otherwise = case resTy of
-        ConDeclGADT{} -> (decltt (keyword "where"), repeat empty)
+        ConDeclGADT{} -> (text "where", repeat empty)
         _             -> (empty, (decltt (text "=") : repeat (decltt (text "|"))))
 
     constrBit
       | null cons = Nothing
       | otherwise = Just $
+          text "\\enspace" <+> emph (text "Constructors") <> text "\\par" $$
           text "\\haddockbeginconstrs" $$
           vcat (zipWith (ppSideBySideConstr subdocs unicode) leaders cons) $$
           text "\\end{tabulary}\\par"
 
     patternBit
-      | null cons = Nothing
-      | otherwise = Just $
+      | null pats = Nothing
+      | otherwise = Just $ 
+          text "\\enspace" <+> emph (text "Bundled Patterns") <> text "\\par" $$
           text "\\haddockbeginconstrs" $$
-          vcat [ hsep [ keyword "pattern"
-                      , hsep $ punctuate comma $ map (ppDocBinder . unLoc) lnames
-                      , dcolon unicode
-                      , ppLType unicode (hsSigType ty)
-                      ] <-> rDoc (fmap _doc . combineDocumentation . fst $ d)
-               | (SigD (PatSynSig lnames ty),d) <- pats
+          vcat [ empty <-> ppSideBySidePat lnames typ d unicode
+               | (SigD _ (PatSynSig _ lnames typ), d) <- pats
                ] $$
           text "\\end{tabulary}\\par"
 
@@ -625,41 +664,102 @@ ppConstrHdr forall tvs ctxt unicode
       False -> empty
 
 
-ppSideBySideConstr :: [(DocName, DocForDecl DocName)] -> Bool -> LaTeX
-                   -> LConDecl DocNameI -> LaTeX
-ppSideBySideConstr subdocs unicode leader (L _ con@(ConDeclH98 {})) =
-  leader <->
-  case con_details con of
-
-    PrefixCon args ->
-      decltt (hsep ((header_ unicode <+> ppOcc) :
-                 map (ppLParendType unicode) args))
-      <-> rDoc mbDoc <+> nl
-
-    RecCon (L _ fields) ->
-      (decltt (header_ unicode <+> ppOcc)
-        <-> rDoc mbDoc <+> nl)
-      $$
-      doRecordFields fields
-
-    InfixCon arg1 arg2 ->
-      decltt (hsep [ header_ unicode <+> ppLParendType unicode arg1,
-                 ppOcc,
-                 ppLParendType unicode arg2 ])
-      <-> rDoc mbDoc <+> nl
+-- | Pretty-print a constructor
+ppSideBySideConstr :: [(DocName, DocForDecl DocName)]  -- ^ all decl docs
+                   -> Bool                             -- ^ unicode
+                   -> LaTeX                            -- ^ prefix to decl
+                   -> LConDecl DocNameI                -- ^ constructor decl
+                   -> LaTeX
+ppSideBySideConstr subdocs unicode leader (L _ con) =
+  leader <-> decltt decl <-> rDoc mbDoc <+> nl
+  $$ fieldPart
+  where
+    -- Find the name of a constructors in the decl (`getConName` always returns
+    -- a non-empty list)
+    aConName = unLoc (head (getConNames con))
+
+    occ      = map (nameOccName . getName . unLoc) $ getConNames con
+
+    ppOcc      = cat (punctuate comma (map ppBinder occ))
+    ppOccInfix = cat (punctuate comma (map ppBinderInfix occ))
+
+    -- Extract out the map of of docs corresponding to the constructors arguments
+    argDocs = maybe Map.empty snd (lookup aConName subdocs)
+    hasArgDocs = not $ Map.null argDocs
+
+    -- First line of the constructor (no doc, no fields, single-line)
+    decl = case con of
+      ConDeclH98{ con_args = det
+                , con_ex_tvs = vars
+                , con_mb_cxt = cxt
+                } -> let tyVars = map (getName . hsLTyVarName) vars
+                         context = unLoc (fromMaybe (noLoc []) cxt)
+                         forall_ = False
+                         header_ = ppConstrHdr forall_ tyVars context unicode
+                     in case det of
+        -- Prefix constructor, e.g. 'Just a'
+        PrefixCon args
+          | hasArgDocs -> header_ <+> ppOcc
+          | otherwise -> hsep [ header_
+                              , ppOcc
+                              , hsep (map (ppLParendType unicode) args)
+                              ]
+
+        -- Record constructor, e.g. 'Identity { runIdentity :: a }'
+        RecCon _ ->  header_ <+> ppOcc
+
+        -- Infix constructor, e.g. 'a :| [a]'
+        InfixCon arg1 arg2
+          | hasArgDocs -> header_ <+> ppOcc
+          | otherwise -> hsep [ header_
+                              , ppLParendType unicode arg1
+                              , ppOccInfix
+                              , ppLParendType unicode arg2
+                              ]
+
+      ConDeclGADT{}
+        | hasArgDocs || not (isEmpty fieldPart) -> ppOcc
+        | otherwise -> hsep [ ppOcc
+                            , dcolon unicode
+                            -- ++AZ++ make this prepend "{..}" when it is a record style GADT
+                            , ppLType unicode (getGADTConType con)
+                            ]
+      XConDecl{} -> panic "haddock:ppSideBySideConstr"
+
+    fieldPart = case (con, getConArgs con) of
+        -- Record style GADTs
+        (ConDeclGADT{}, RecCon _)            -> doConstrArgsWithDocs []
+
+        -- Regular record declarations
+        (_, RecCon (L _ fields))             -> doRecordFields fields
+
+        -- Any GADT or a regular H98 prefix data constructor
+        (_, PrefixCon args)     | hasArgDocs -> doConstrArgsWithDocs args
+
+        -- An infix H98 data constructor
+        (_, InfixCon arg1 arg2) | hasArgDocs -> doConstrArgsWithDocs [arg1,arg2]
+
+        _ -> empty
 
- where
     doRecordFields fields =
-        vcat (map (ppSideBySideField subdocs unicode) (map unLoc fields))
+      vcat [ empty <-> tt (text begin) <+> ppSideBySideField subdocs unicode field <+> nl
+           | (begin, L _ field) <- zip ("\\qquad \\{" : repeat "\\qquad ,") fields
+           ]
+      $$
+      empty <-> tt (text "\\qquad \\}") <+> nl
 
+    doConstrArgsWithDocs args = vcat $ map (\l -> empty <-> text "\\qquad" <+> l) $ case con of
+      ConDeclH98{} ->
+        [ decltt (ppLParendType unicode arg) <-> rDoc (fmap _doc mdoc) <+> nl
+        | (i, arg) <- zip [0..] args
+        , let mdoc = Map.lookup i argDocs
+        ]
+      ConDeclGADT{} ->
+        [ l <+> text "\\enspace" <+> r
+        | (l,r) <- ppSubSigLike unicode (unLoc (getGADTConType con)) argDocs subdocs (dcolon unicode)
+        ]
+      XConDecl{} -> panic "haddock:doConstrArgsWithDocs"
 
-    header_ = ppConstrHdr False tyVars context
-    occ     = map (nameOccName . getName . unLoc) $ getConNames con
-    ppOcc   = case occ of
-      [one] -> ppBinder one
-      _     -> cat (punctuate comma (map ppBinder occ))
-    tyVars  = tyvarNames (fromMaybe (HsQTvs PlaceHolder [] PlaceHolder) (con_qvars con))
-    context = unLoc (fromMaybe (noLoc []) (con_cxt con))
 
     -- 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.
@@ -668,147 +768,49 @@ ppSideBySideConstr subdocs unicode leader (L _ con@(ConDeclH98 {})) =
               (cn:_) -> lookup (unLoc cn) subdocs >>=
                         fmap _doc . combineDocumentation . fst
 
-ppSideBySideConstr subdocs unicode leader (L _ con@(ConDeclGADT {})) =
-  leader <->
-  doGADTCon (hsib_body $ con_type con)
-
- where
-    doGADTCon resTy = decltt (ppOcc <+> dcolon unicode <+>
-                               ppLType unicode resTy
-                            ) <-> rDoc mbDoc
-
-    occ     = map (nameOccName . getName . unLoc) $ getConNames con
-    ppOcc   = case occ of
-      [one] -> ppBinder one
-      _     -> cat (punctuate comma (map ppBinder occ))
-
-    -- 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.
-    mbDoc = case getConNames con of
-              [] -> panic "empty con_names"
-              (cn:_) -> lookup (unLoc cn) subdocs >>=
-                        fmap _doc . combineDocumentation . fst
-{- old
-
-ppSideBySideConstr :: [(DocName, DocForDecl DocName)] -> Bool -> LaTeX
-                   -> LConDecl DocName -> LaTeX
-ppSideBySideConstr subdocs unicode leader (L loc con) =
-  leader <->
-  case con_res con of
-  ResTyH98 -> case con_details con of
-
-    PrefixCon args ->
-      decltt (hsep ((header_ unicode <+> ppOcc) :
-                 map (ppLParendType unicode) args))
-      <-> rDoc mbDoc <+> nl
-
-    RecCon (L _ fields) ->
-      (decltt (header_ unicode <+> ppOcc)
-        <-> rDoc mbDoc <+> nl)
-      $$
-      doRecordFields fields
-
-    InfixCon arg1 arg2 ->
-      decltt (hsep [ header_ unicode <+> ppLParendType unicode arg1,
-                 ppOcc,
-                 ppLParendType unicode arg2 ])
-      <-> rDoc mbDoc <+> nl
-
-  ResTyGADT _ resTy -> case con_details con of
-    -- prefix & infix could also use hsConDeclArgTys if it seemed to
-    -- simplify the code.
-    PrefixCon args -> doGADTCon args resTy
-    cd@(RecCon (L _ fields)) -> doGADTCon (hsConDeclArgTys cd) resTy <+> nl $$
-                                     doRecordFields fields
-    InfixCon arg1 arg2 -> doGADTCon [arg1, arg2] resTy
-
- where
-    doRecordFields fields =
-        vcat (map (ppSideBySideField subdocs unicode) (map unLoc fields))
-
-    doGADTCon args resTy = decltt (ppOcc <+> dcolon unicode <+>
-                               ppLType unicode (mk_forall $ mk_phi $
-                                                foldr mkFunTy resTy args)
-                            ) <-> rDoc mbDoc
-
-
-    header_ = ppConstrHdr (con_explicit con) tyVars context
-    occ     = map (nameOccName . getName . unLoc) $ con_names con
-    ppOcc   = case occ of
-      [one] -> ppBinder one
-      _     -> cat (punctuate comma (map ppBinder occ))
-    ltvs    = con_qvars con
-    tyVars  = tyvarNames (con_qvars con)
-    context = unLoc (con_cxt con)
-
-    mk_forall ty | con_explicit con = L loc (HsForAllTy (hsQTvExplicit ltvs) ty)
-                 | otherwise        = ty
-    mk_phi ty | null context = ty
-              | otherwise    = L loc (HsQualTy (con_cxt con) ty)
-
-    -- 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.
-    mbDoc = case con_names con of
-              [] -> panic "empty con_names"
-              (cn:_) -> lookup (unLoc cn) subdocs >>=
-                        fmap _doc . combineDocumentation . fst
-    mkFunTy a b = noLoc (HsFunTy a b)
--}
 
+-- | Pretty-print a record field
 ppSideBySideField :: [(DocName, DocForDecl DocName)] -> Bool -> ConDeclField DocNameI ->  LaTeX
-ppSideBySideField subdocs unicode (ConDeclField names ltype _) =
+ppSideBySideField subdocs unicode (ConDeclField _ names ltype _) =
   decltt (cat (punctuate comma (map (ppBinder . rdrNameOcc . unLoc . rdrNameFieldOcc . unLoc) names))
     <+> dcolon unicode <+> ppLType unicode ltype) <-> rDoc mbDoc
   where
     -- 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 (selectorFieldOcc $ unLoc $ head names) subdocs >>= fmap _doc . combineDocumentation . fst
-
--- {-
--- ppHsFullConstr :: HsConDecl -> LaTeX
--- ppHsFullConstr (HsConDecl _ nm tvs ctxt typeList doc) =
---      declWithDoc False doc (
--- 	hsep ((ppHsConstrHdr tvs ctxt +++
--- 		ppHsBinder False nm) : map ppHsBangType typeList)
---       )
--- ppHsFullConstr (HsRecDecl _ nm tvs ctxt fields doc) =
---    td << vanillaTable << (
---      case doc of
---        Nothing -> aboves [hdr, fields_html]
---        Just _  -> aboves [hdr, constr_doc, fields_html]
---    )
---
---   where hdr = declBox (ppHsConstrHdr tvs ctxt +++ ppHsBinder False nm)
---
--- 	constr_doc
--- 	  | isJust doc = docBox (docToLaTeX (fromJust doc))
--- 	  | otherwise  = LaTeX.emptyTable
---
--- 	fields_html =
--- 	   td <<
--- 	      table ! [width "100%", cellpadding 0, cellspacing 8] << (
--- 		   aboves (map ppFullField (concat (map expandField fields)))
--- 		)
--- -}
---
--- ppShortField :: Bool -> Bool -> ConDeclField DocName -> LaTeX
--- ppShortField summary unicode (ConDeclField (L _ name) ltype _)
---   = tda [theclass "recfield"] << (
---       ppBinder summary (docNameOcc name)
---       <+> dcolon unicode <+> ppLType unicode ltype
---     )
---
--- {-
--- ppFullField :: HsFieldDecl -> LaTeX
--- ppFullField (HsFieldDecl [n] ty doc)
---   = declWithDoc False doc (
--- 	ppHsBinder False n <+> dcolon <+> ppHsBangType ty
---     )
--- ppFullField _ = error "ppFullField"
---
--- expandField :: HsFieldDecl -> [HsFieldDecl]
--- expandField (HsFieldDecl ns ty doc) = [ HsFieldDecl [n] ty doc | n <- ns ]
--- -}
+    mbDoc = lookup (extFieldOcc $ unLoc $ head names) subdocs >>= fmap _doc . combineDocumentation . fst
+ppSideBySideField _ _ (XConDeclField _) = panic "haddock:ppSideBySideField"
+
+
+-- | Pretty-print a bundled pattern synonym
+ppSideBySidePat :: [Located DocName]    -- ^ pattern name(s)
+                -> LHsSigType DocNameI  -- ^ type of pattern(s)
+                -> DocForDecl DocName   -- ^ doc map
+                -> Bool                 -- ^ unicode
+                -> LaTeX
+ppSideBySidePat lnames typ (doc, argDocs) unicode =
+  decltt decl <-> rDoc mDoc <+> nl
+  $$ fieldPart
+  where
+    hasArgDocs = not $ Map.null argDocs
+    ppOcc = hsep (punctuate comma (map (ppDocBinder . unLoc) lnames))
+
+    decl | hasArgDocs = keyword "pattern" <+> ppOcc
+         | otherwise = hsep [ keyword "pattern"
+                            , ppOcc
+                            , dcolon unicode
+                            , ppLType unicode (hsSigType typ)
+                            ]
+
+    fieldPart
+      | not hasArgDocs = empty
+      | otherwise = vcat
+          [ empty <-> text "\\qquad" <+> l <+> text "\\enspace" <+> r
+          | (l,r) <- ppSubSigLike unicode (unLoc patTy) argDocs [] (dcolon unicode)
+          ]
+
+    patTy = hsSigType typ
+
+    mDoc = fmap _doc $ combineDocumentation doc
 
 
 -- | Print the LHS of a data\/newtype declaration.
@@ -824,6 +826,7 @@ ppDataHeader (DataDecl { tcdLName = L _ name, tcdTyVars = tyvars
     ppAppDocNameNames False name (tyvarNames tyvars)
 ppDataHeader _ _ = error "ppDataHeader: illegal argument"
 
+
 --------------------------------------------------------------------------------
 -- * Type applications
 --------------------------------------------------------------------------------
@@ -955,57 +958,57 @@ ppr_mono_lty ctxt_prec ty unicode = ppr_mono_ty ctxt_prec (unLoc ty) unicode
 
 
 ppr_mono_ty :: Int -> HsType DocNameI -> Bool -> LaTeX
-ppr_mono_ty ctxt_prec (HsForAllTy tvs ty) unicode
+ppr_mono_ty ctxt_prec (HsForAllTy _ tvs ty) unicode
   = maybeParen ctxt_prec pREC_FUN $
     sep [ hsep (forallSymbol unicode : ppTyVars tvs) <> dot
         , ppr_mono_lty pREC_TOP ty unicode ]
-ppr_mono_ty ctxt_prec (HsQualTy ctxt ty) unicode
+ppr_mono_ty ctxt_prec (HsQualTy _ ctxt ty) unicode
   = maybeParen ctxt_prec pREC_FUN $
     sep [ ppLContext ctxt unicode
         , ppr_mono_lty pREC_TOP ty unicode ]
 
-ppr_mono_ty _         (HsBangTy b ty)     u = ppBang b <> ppLParendType u ty
-ppr_mono_ty _         (HsTyVar NotPromoted (L _ name)) _ = ppDocName name
-ppr_mono_ty _         (HsTyVar Promoted    (L _ name)) _ = char '\'' <> ppDocName name
-ppr_mono_ty ctxt_prec (HsFunTy ty1 ty2)   u = ppr_fun_ty ctxt_prec ty1 ty2 u
-ppr_mono_ty _         (HsTupleTy con tys) u = tupleParens con (map (ppLType u) tys)
-ppr_mono_ty _         (HsSumTy tys) u       = sumParens (map (ppLType u) tys)
-ppr_mono_ty _         (HsKindSig ty kind) u = parens (ppr_mono_lty pREC_TOP ty u <+> dcolon u <+> ppLKind u kind)
-ppr_mono_ty _         (HsListTy ty)       u = brackets (ppr_mono_lty pREC_TOP ty u)
-ppr_mono_ty _         (HsPArrTy ty)       u = pabrackets (ppr_mono_lty pREC_TOP ty u)
-ppr_mono_ty _         (HsIParamTy (L _ n) ty) u = brackets (ppIPName n <+> dcolon u <+> ppr_mono_lty pREC_TOP ty u)
+ppr_mono_ty _         (HsBangTy _ b ty)     u = ppBang b <> ppLParendType u ty
+ppr_mono_ty _         (HsTyVar _ NotPromoted (L _ name)) _ = ppDocName name
+ppr_mono_ty _         (HsTyVar _ Promoted    (L _ name)) _ = char '\'' <> ppDocName name
+ppr_mono_ty ctxt_prec (HsFunTy _ ty1 ty2)   u = ppr_fun_ty ctxt_prec ty1 ty2 u
+ppr_mono_ty _         (HsTupleTy _ con tys) u = tupleParens con (map (ppLType u) tys)
+ppr_mono_ty _         (HsSumTy _ tys) u       = sumParens (map (ppLType u) tys)
+ppr_mono_ty _         (HsKindSig _ ty kind) u = parens (ppr_mono_lty pREC_TOP ty u <+> dcolon u <+> ppLKind u kind)
+ppr_mono_ty _         (HsListTy _ ty)       u = brackets (ppr_mono_lty pREC_TOP ty u)
+ppr_mono_ty _         (HsPArrTy _ ty)       u = pabrackets (ppr_mono_lty pREC_TOP ty u)
+ppr_mono_ty _         (HsIParamTy _ (L _ n) ty) u = brackets (ppIPName n <+> dcolon u <+> ppr_mono_lty pREC_TOP ty u)
 ppr_mono_ty _         (HsSpliceTy {})     _ = error "ppr_mono_ty HsSpliceTy"
-ppr_mono_ty _         (HsRecTy {})        _ = error "ppr_mono_ty HsRecTy"
-ppr_mono_ty _         (HsCoreTy {})       _ = error "ppr_mono_ty HsCoreTy"
-ppr_mono_ty _         (HsExplicitListTy Promoted _ tys) u = Pretty.quote $ brackets $ hsep $ punctuate comma $ map (ppLType u) tys
-ppr_mono_ty _         (HsExplicitListTy NotPromoted _ tys) u = brackets $ hsep $ punctuate comma $ map (ppLType u) tys
+ppr_mono_ty _         (HsRecTy {})        _ = text "{..}"
+ppr_mono_ty _         (XHsType (NHsCoreTy {}))  _ = error "ppr_mono_ty HsCoreTy"
+ppr_mono_ty _         (HsExplicitListTy _ Promoted tys) u = Pretty.quote $ brackets $ hsep $ punctuate comma $ map (ppLType u) tys
+ppr_mono_ty _         (HsExplicitListTy _ NotPromoted tys) u = brackets $ hsep $ punctuate comma $ map (ppLType u) tys
 ppr_mono_ty _         (HsExplicitTupleTy _ tys) u = Pretty.quote $ parenList $ map (ppLType u) tys
 
-ppr_mono_ty ctxt_prec (HsEqTy ty1 ty2) unicode
+ppr_mono_ty ctxt_prec (HsEqTy _ ty1 ty2) unicode
   = maybeParen ctxt_prec pREC_OP $
     ppr_mono_lty pREC_OP ty1 unicode <+> char '~' <+> ppr_mono_lty pREC_OP ty2 unicode
 
-ppr_mono_ty ctxt_prec (HsAppTy fun_ty arg_ty) unicode
+ppr_mono_ty ctxt_prec (HsAppTy _ fun_ty arg_ty) unicode
   = maybeParen ctxt_prec pREC_CON $
     hsep [ppr_mono_lty pREC_FUN fun_ty unicode, ppr_mono_lty pREC_CON arg_ty unicode]
 
-ppr_mono_ty ctxt_prec (HsOpTy ty1 op ty2) unicode
+ppr_mono_ty ctxt_prec (HsOpTy _ ty1 op ty2) unicode
   = maybeParen ctxt_prec pREC_FUN $
     ppr_mono_lty pREC_OP ty1 unicode <+> ppr_op <+> ppr_mono_lty pREC_OP ty2 unicode
   where
     ppr_op = if not (isSymOcc occName) then char '`' <> ppLDocName op <> char '`' else ppLDocName op
     occName = nameOccName . getName . unLoc $ op
 
-ppr_mono_ty ctxt_prec (HsParTy ty) unicode
+ppr_mono_ty ctxt_prec (HsParTy _ ty) unicode
 --  = parens (ppr_mono_lty pREC_TOP ty)
   = ppr_mono_lty ctxt_prec ty unicode
 
-ppr_mono_ty ctxt_prec (HsDocTy ty _) unicode
+ppr_mono_ty ctxt_prec (HsDocTy _ ty _) unicode
   = ppr_mono_lty ctxt_prec ty unicode
 
 ppr_mono_ty _ (HsWildCardTy (AnonWildCard _)) _ = char '_'
 
-ppr_mono_ty _ (HsTyLit t) u = ppr_tylit t u
+ppr_mono_ty _ (HsTyLit _ t) u = ppr_tylit t u
 
 ppr_mono_ty _ (HsAppsTy {}) _ = panic "ppr_mono_ty:HsAppsTy"
 
@@ -1036,6 +1039,11 @@ ppBinder n
   | isInfixName n = parens $ ppOccName n
   | otherwise     = ppOccName n
 
+ppBinderInfix :: OccName -> LaTeX
+ppBinderInfix n
+  | isInfixName n = ppOccName n
+  | otherwise     = cat [ char '`', ppOccName n, char '`' ]
+
 isInfixName :: OccName -> Bool
 isInfixName n = isVarSym n || isConSym n
 
diff --git a/haddock-api/src/Haddock/Backends/Xhtml.hs b/haddock-api/src/Haddock/Backends/Xhtml.hs
index c9a262a4..6da6a2e8 100644
--- a/haddock-api/src/Haddock/Backends/Xhtml.hs
+++ b/haddock-api/src/Haddock/Backends/Xhtml.hs
@@ -667,7 +667,7 @@ numberSectionHeadings = go 1
 
 processExport :: Bool -> LinksInfo -> Bool -> Maybe Package -> Qualification
               -> ExportItem DocNameI -> Maybe Html
-processExport _ _ _ _ _ ExportDecl { expItemDecl = L _ (InstD _) } = Nothing -- Hide empty instances
+processExport _ _ _ _ _ ExportDecl { expItemDecl = L _ (InstD {}) } = Nothing -- Hide empty instances
 processExport summary _ _ pkg qual (ExportGroup lev id0 doc)
   = nothingIf summary $ groupHeading lev id0 << docToHtml (Just id0) pkg qual (mkMeta doc)
 processExport summary links unicode pkg qual (ExportDecl decl pats doc subdocs insts fixities splice)
diff --git a/haddock-api/src/Haddock/Backends/Xhtml/Decl.hs b/haddock-api/src/Haddock/Backends/Xhtml/Decl.hs
index 815ecee9..3fbe6eaf 100644
--- a/haddock-api/src/Haddock/Backends/Xhtml/Decl.hs
+++ b/haddock-api/src/Haddock/Backends/Xhtml/Decl.hs
@@ -39,24 +39,34 @@ import GHC.Exts
 import Name
 import BooleanFormula
 import RdrName ( rdrNameOcc )
-
-ppDecl :: Bool -> LinksInfo -> LHsDecl DocNameI
-       -> [(HsDecl DocNameI, DocForDecl DocName)]
-       -> DocForDecl DocName ->  [DocInstance DocNameI] -> [(DocName, Fixity)]
-       -> [(DocName, DocForDecl DocName)] -> Splice -> Unicode
-       -> Maybe Package -> Qualification -> Html
+import Outputable ( panic )
+
+-- | Pretty print a declaration
+ppDecl :: Bool                                     -- ^ print summary info only
+       -> LinksInfo                                -- ^ link information
+       -> LHsDecl DocNameI                         -- ^ declaration to print
+       -> [(HsDecl DocNameI, DocForDecl DocName)]  -- ^ relevant pattern synonyms
+       -> DocForDecl DocName                       -- ^ documentation for this decl
+       -> [DocInstance DocNameI]                   -- ^ relevant instances
+       -> [(DocName, Fixity)]                      -- ^ relevant fixities
+       -> [(DocName, DocForDecl DocName)]          -- ^ documentation for all decls
+       -> Splice
+       -> Unicode                                  -- ^ unicode output
+       -> Maybe Package
+       -> Qualification
+       -> Html
 ppDecl summ links (L loc decl) pats (mbDoc, fnArgsDoc) instances fixities subdocs splice unicode pkg qual = case decl of
-  TyClD (FamDecl d)            -> ppTyFam summ False links instances fixities loc mbDoc d splice unicode pkg qual
-  TyClD d@(DataDecl {})        -> ppDataDecl summ links instances fixities subdocs loc mbDoc d pats splice unicode pkg qual
-  TyClD d@(SynDecl {})         -> ppTySyn summ links fixities loc (mbDoc, fnArgsDoc) d splice unicode pkg qual
-  TyClD d@(ClassDecl {})       -> ppClassDecl summ links instances fixities loc mbDoc subdocs d splice unicode pkg qual
-  SigD (TypeSig lnames lty)    -> ppLFunSig summ links loc (mbDoc, fnArgsDoc) lnames
+  TyClD _ (FamDecl _ d)          -> ppTyFam summ False links instances fixities loc mbDoc d splice unicode pkg qual
+  TyClD _ d@(DataDecl {})        -> ppDataDecl summ links instances fixities subdocs loc mbDoc d pats splice unicode pkg qual
+  TyClD _ d@(SynDecl {})         -> ppTySyn summ links fixities loc (mbDoc, fnArgsDoc) d splice unicode pkg qual
+  TyClD _ d@(ClassDecl {})       -> ppClassDecl summ links instances fixities loc mbDoc subdocs d splice unicode pkg qual
+  SigD _ (TypeSig _ lnames lty)  -> ppLFunSig summ links loc (mbDoc, fnArgsDoc) lnames
                                          (hsSigWcType lty) fixities splice unicode pkg qual
-  SigD (PatSynSig lnames ty)   -> ppLPatSig summ links loc (mbDoc, fnArgsDoc) lnames
-                                         ty fixities splice unicode pkg qual
-  ForD d                       -> ppFor summ links loc (mbDoc, fnArgsDoc) d fixities splice unicode pkg qual
-  InstD _                      -> noHtml
-  DerivD _                     -> noHtml
+  SigD _ (PatSynSig _ lnames lty) -> ppLPatSig summ links loc (mbDoc, fnArgsDoc) lnames
+                                         (hsSigType lty) fixities splice unicode pkg qual
+  ForD _ d                       -> ppFor summ links loc (mbDoc, fnArgsDoc) d fixities splice unicode pkg qual
+  InstD _ _                      -> noHtml
+  DerivD _ _                     -> noHtml
   _                            -> error "declaration not supported by ppDecl"
 
 
@@ -76,21 +86,18 @@ ppFunSig summary links loc doc docnames typ fixities splice unicode pkg qual =
   where
     pp_typ = ppLType unicode qual HideEmptyContexts typ
 
-ppLPatSig :: Bool -> LinksInfo -> SrcSpan -> DocForDecl DocName ->
-             [Located DocName] -> LHsSigType DocNameI ->
-             [(DocName, Fixity)] ->
-             Splice -> Unicode -> Maybe Package -> Qualification -> Html
-ppLPatSig summary links loc (doc, _argDocs) docnames typ fixities splice
-          unicode pkg qual
-  | summary = pref1
-  | otherwise = topDeclElem links loc splice (map unLoc docnames) (pref1 <+> ppFixities fixities qual)
-                +++ docSection Nothing pkg qual doc
+-- | Pretty print a pattern synonym
+ppLPatSig :: Bool -> LinksInfo -> SrcSpan -> DocForDecl DocName
+          -> [Located DocName]     -- ^ names of patterns in declaration
+          -> LHsType DocNameI      -- ^ type of patterns in declaration
+          -> [(DocName, Fixity)]
+          -> Splice -> Unicode -> Maybe Package -> Qualification -> Html
+ppLPatSig summary links loc doc lnames typ fixities splice unicode pkg qual =
+  ppSigLike summary links loc (keyword "pattern") doc (map unLoc lnames) fixities
+            (unLoc typ, pp_typ) splice unicode pkg qual (patSigContext typ)
   where
-    pref1 = hsep [ keyword "pattern"
-                 , hsep $ punctuate comma $ map (ppBinder summary . getOccName) docnames
-                 , dcolon unicode
-                 , ppPatSigType unicode qual (hsSigType typ)
-                 ]
+    pp_typ = ppPatSigType unicode qual typ
+
 
 ppSigLike :: Bool -> LinksInfo -> SrcSpan -> Html -> DocForDecl DocName ->
              [DocName] -> [(DocName, Fixity)] -> (HsType DocNameI, Html) ->
@@ -99,7 +106,7 @@ ppSigLike summary links loc leader doc docnames fixities (typ, pp_typ)
           splice unicode pkg qual emptyCtxts =
   ppTypeOrFunSig summary links loc docnames typ doc
     ( addFixities $ leader <+> ppTypeSig summary occnames pp_typ unicode
-    , addFixities . concatHtml . punctuate comma $ map (ppBinder False) occnames
+    , (leader <+>) . addFixities . concatHtml . punctuate comma $ map (ppBinder False) occnames
     , dcolon unicode
     )
     splice unicode pkg qual emptyCtxts
@@ -118,36 +125,72 @@ ppTypeOrFunSig summary links loc docnames typ (doc, argDocs) (pref1, pref2, sep)
                splice unicode pkg qual emptyCtxts
   | summary = pref1
   | Map.null argDocs = topDeclElem links loc splice docnames pref1 +++ docSection curName pkg qual doc
-  | otherwise = topDeclElem links loc splice docnames pref2 +++
-      subArguments pkg qual (do_args 0 sep typ) +++ docSection curName pkg qual doc
+  | otherwise = topDeclElem links loc splice docnames pref2
+                  +++ subArguments pkg qual (ppSubSigLike unicode qual typ argDocs [] sep emptyCtxts)
+                  +++ docSection curName pkg qual doc
   where
     curName = getName <$> listToMaybe docnames
+
+
+-- This splits up a type signature along `->` and adds docs (when they exist) to
+-- the arguments.
+--
+-- If one passes in a list of the available subdocs, any top-level `HsRecTy`
+-- found will be expanded out into their fields.
+ppSubSigLike :: Unicode -> Qualification
+             -> HsType DocNameI                  -- ^ type signature
+             -> FnArgsDoc DocName                -- ^ docs to add
+             -> [(DocName, DocForDecl DocName)]  -- ^ all subdocs (useful when
+                                                 -- we expand an `HsRecTy`)
+             -> Html -> HideEmptyContexts -> [SubDecl]
+ppSubSigLike unicode qual typ argDocs subdocs sep emptyCtxts = do_args 0 sep typ
+  where
     argDoc n = Map.lookup n argDocs
 
     do_largs n leader (L _ t) = do_args n leader t
 
     do_args :: Int -> Html -> HsType DocNameI -> [SubDecl]
-    do_args n leader (HsForAllTy tvs ltype)
+    do_args n leader (HsForAllTy _ tvs ltype)
       = do_largs n leader' ltype
       where
         leader' = leader <+> ppForAll tvs unicode qual
 
-    do_args n leader (HsQualTy lctxt ltype)
+    do_args n leader (HsQualTy _ lctxt ltype)
       | null (unLoc lctxt)
       = do_largs n leader ltype
       | otherwise
       = (leader <+> ppLContextNoArrow lctxt unicode qual emptyCtxts, Nothing, [])
         : do_largs n (darrow unicode) ltype
 
-    do_args n leader (HsFunTy lt r)
+    do_args n leader (HsFunTy _ (L _ (HsRecTy _ fields)) r)
+      = [ (ldr <+> html, mdoc, subs)
+        | (L _ field, ldr) <- zip fields (leader <+> gadtOpen : repeat gadtComma)
+        , let (html, mdoc, subs) = ppSideBySideField subdocs unicode qual field
+        ]
+        ++ do_largs (n+1) (gadtEnd <+> arrow unicode) r
+
+    do_args n leader (HsFunTy _ lt r)
       = (leader <+> ppLFunLhType unicode qual emptyCtxts lt, argDoc n, [])
         : do_largs (n+1) (arrow unicode) r
+
     do_args n leader t
       = [(leader <+> ppType unicode qual emptyCtxts t, argDoc n, [])]
 
+
+    -- FIXME: this should be done more elegantly
+    --
+    -- We need 'gadtComma' and 'gadtEnd' to line up with the `{` from
+    -- 'gadtOpen', so we add 3 spaces to cover for `-> `/`:: ` (3 in unicode
+    -- mode since `->` and `::` are rendered as single characters.
+    gadtComma = concatHtml (replicate (if unicode then 2 else 3) spaceHtml) <> toHtml ","
+    gadtEnd = concatHtml (replicate (if unicode then 2 else 3) spaceHtml) <> toHtml "}"
+    gadtOpen = toHtml "{"
+
+
+
 ppForAll :: [LHsTyVarBndr DocNameI] -> Unicode -> Qualification -> Html
 ppForAll tvs unicode qual =
-  case [ppKTv n k | L _ (KindedTyVar (L _ n) k) <- tvs] of
+  case [ppKTv n k | L _ (KindedTyVar _ (L _ n) k) <- tvs] of
     [] -> noHtml
     ts -> forallSymbol unicode <+> hsep ts +++ dot
   where ppKTv n k = parens $
@@ -186,7 +229,7 @@ tyvarNames = map (getName . hsLTyVarName) . hsQTvExplicit
 ppFor :: Bool -> LinksInfo -> SrcSpan -> DocForDecl DocName
       -> ForeignDecl DocNameI -> [(DocName, Fixity)]
       -> Splice -> Unicode -> Maybe Package -> Qualification -> Html
-ppFor summary links loc doc (ForeignImport (L _ name) typ _ _) fixities
+ppFor summary links loc doc (ForeignImport _ (L _ name) typ _) fixities
       splice unicode pkg qual
   = ppFunSig summary links loc doc [name] (hsSigType typ) fixities splice unicode pkg qual
 ppFor _ _ _ _ _ _ _ _ _ _ = error "ppFor"
@@ -279,12 +322,14 @@ ppTyFamHeader summary associated d@(FamilyDecl { fdInfo = info
      ClosedTypeFamily _ -> keyword "where ..."
      _                  -> mempty
   )
+ppTyFamHeader _ _ (XFamilyDecl _) _ _ = panic "haddock;ppTyFamHeader"
 
 ppResultSig :: FamilyResultSig DocNameI -> Unicode -> Qualification -> Html
 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
+    NoSig _               -> noHtml
+    KindSig _ kind        -> dcolon unicode  <+> ppLKind unicode qual kind
+    TyVarSig _ (L _ bndr) -> equals <+> ppHsTyVarBndr unicode qual bndr
+    XFamilyResultSig _    -> panic "haddock:ppResultSig"
 
 ppPseudoFamilyHeader :: Unicode -> Qualification -> PseudoFamilyDecl DocNameI
                      -> Html
@@ -330,6 +375,8 @@ ppTyFam summary associated links instances fixities loc doc decl splice unicode
       = ( ppAppNameTypes (unLoc n) (map unLoc ts) unicode qual
           <+> equals <+> ppType unicode qual HideEmptyContexts (unLoc rhs)
         , Nothing, [] )
+    ppTyFamEqn (XHsImplicitBndrs _) = panic "haddock:ppTyFam"
+    ppTyFamEqn (HsIB { hsib_body = XFamEqn _}) = panic "haddock:ppTyFam"
 
 
 
@@ -363,6 +410,7 @@ ppAssocType summ links doc (L loc decl) fixities splice unicode pkg qual =
 ppFamDeclBinderWithVars :: Bool -> Unicode -> Qualification -> FamilyDecl DocNameI -> Html
 ppFamDeclBinderWithVars summ unicode qual (FamilyDecl { fdLName = lname, fdTyVars = tvs }) =
   ppAppDocNameTyVarBndrs summ unicode qual (unLoc lname) (hsq_explicit tvs)
+ppFamDeclBinderWithVars _ _ _ (XFamilyDecl _) = panic "haddock:ppFamDeclBinderWithVars"
 
 -- | Print a newtype / data binder and its variables
 ppDataBinderWithVars :: Bool -> Unicode -> Qualification -> TyClDecl DocNameI -> Html
@@ -477,7 +525,7 @@ ppShortClassDecl summary links (ClassDecl { tcdCtxt = lctxt, tcdLName = lname, t
 
             [ ppFunSig summary links loc doc names (hsSigWcType typ)
                        [] splice unicode pkg qual
-              | L _ (TypeSig lnames typ) <- sigs
+              | L _ (TypeSig _ lnames typ) <- sigs
               , let doc = lookupAnySubdoc (head names) subdocs
                     names = map unLoc lnames ]
               -- FIXME: is taking just the first name ok? Is it possible that
@@ -525,7 +573,7 @@ ppClassDecl summary links instances fixities loc d subdocs
 
     methodBit = subMethods [ ppFunSig summary links loc doc [name] (hsSigType typ)
                                       subfixs splice unicode pkg qual
-                           | L _ (ClassOpSig _ lnames typ) <- lsigs
+                           | L _ (ClassOpSig _ _ lnames typ) <- lsigs
                            , name <- map unLoc lnames
                            , let doc = lookupAnySubdoc name subdocs
                                  subfixs = [ f | f@(n',_) <- fixities
@@ -534,15 +582,15 @@ ppClassDecl summary links instances fixities loc d subdocs
                            -- N.B. taking just the first name is ok. Signatures with multiple names
                            -- are expanded so that each name gets its own signature.
 
-    minimalBit = case [ s | MinimalSig _ (L _ s) <- sigs ] of
+    minimalBit = case [ s | MinimalSig _ _ (L _ s) <- sigs ] of
       -- Miminal complete definition = every shown method
       And xs : _ | sort [getName n | L _ (Var (L _ n)) <- xs] ==
-                   sort [getName n | TypeSig ns _ <- sigs, L _ n <- ns]
+                   sort [getName n | TypeSig _ ns _ <- sigs, L _ n <- ns]
         -> noHtml
 
       -- Minimal complete definition = the only shown method
       Var (L _ n) : _ | [getName n] ==
-                        [getName n' | L _ (TypeSig ns _) <- lsigs, L _ n' <- ns]
+                        [getName n' | L _ (TypeSig _ ns _) <- lsigs, L _ n' <- ns]
         -> noHtml
 
       -- Minimal complete definition = nothing
@@ -645,7 +693,7 @@ ppInstanceSigs :: LinksInfo -> Splice -> Unicode -> Qualification
               -> [Sig DocNameI]
               -> [Html]
 ppInstanceSigs links splice unicode qual sigs = do
-    TypeSig lnames typ <- sigs
+    TypeSig _ lnames typ <- sigs
     let names = map unLoc lnames
         L _ rtyp = hsSigWcType typ
     -- Instance methods signatures are synified and thus don't have a useful
@@ -706,21 +754,27 @@ 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
                    , dcolon unicode
                    , ppPatSigType unicode qual (hsSigType typ)
                    ]
-            | (SigD (PatSynSig lnames typ),_) <- pats
+            | (SigD _ (PatSynSig _ lnames typ),_) <- pats
             ]
 
 
-ppDataDecl :: Bool -> LinksInfo -> [DocInstance DocNameI] -> [(DocName, Fixity)] ->
-              [(DocName, DocForDecl DocName)] ->
-              SrcSpan -> Documentation DocName -> TyClDecl DocNameI ->
-              [(HsDecl DocNameI, DocForDecl DocName)] ->
-              Splice -> Unicode -> Maybe Package -> Qualification -> Html
+-- | Pretty-print a data declaration
+ppDataDecl :: Bool -> LinksInfo
+           -> [DocInstance DocNameI]                  -- ^ relevant instances
+           -> [(DocName, Fixity)]                     -- ^ relevant fixities
+           -> [(DocName, DocForDecl DocName)]         -- ^ all decl documentation
+           -> SrcSpan
+           -> Documentation DocName                   -- ^ this decl's documentation
+           -> TyClDecl DocNameI                       -- ^ this decl
+           -> [(HsDecl DocNameI, DocForDecl DocName)] -- ^ relevant patterns
+           -> Splice -> Unicode -> Maybe Package -> Qualification -> Html
 ppDataDecl summary links instances fixities subdocs loc doc dataDecl pats
            splice unicode pkg qual
 
@@ -733,6 +787,7 @@ 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
@@ -749,25 +804,20 @@ ppDataDecl summary links instances fixities subdocs loc doc dataDecl pats
       [ ppSideBySideConstr subdocs subfixs unicode pkg qual c
       | c <- cons
       , let subfixs = filter (\(n,_) -> any (\cn -> cn == n)
-                                     (map unLoc (getConNames (unLoc c)))) fixities
+                                            (map unLoc (getConNames (unLoc c)))) fixities
       ]
 
     patternBit = subPatterns pkg qual
-      [ (hsep [ keyword "pattern"
-              , hsep $ punctuate comma $ map (ppBinder summary . getOccName) lnames
-              , dcolon unicode
-              , ppPatSigType unicode qual (hsSigType typ)
-              ] <+> ppFixities subfixs qual
-        ,combineDocumentation (fst d), [])
-      | (SigD (PatSynSig lnames typ),d) <- pats
-      , let subfixs = filter (\(n,_) -> any (\cn -> cn == n) (map unLoc lnames)) fixities
+      [ ppSideBySidePat subfixs unicode qual lnames typ d
+      | (SigD _ (PatSynSig _ lnames typ), d) <- pats
+      , let subfixs = filter (\(n,_) -> any (\cn -> cn == n)
+                                            (map unLoc lnames)) fixities
       ]
 
     instancesBit = ppInstances links (OriginData docname) instances
         splice unicode pkg qual
 
 
-
 ppShortConstr :: Bool -> ConDecl DocNameI -> Unicode -> Qualification -> Html
 ppShortConstr summary con unicode qual = cHead <+> cBody <+> cFoot
   where
@@ -777,121 +827,183 @@ ppShortConstr summary con unicode qual = cHead <+> cBody <+> cFoot
 -- returns three pieces: header, body, footer so that header & footer can be
 -- incorporated into the declaration
 ppShortConstrParts :: Bool -> Bool -> ConDecl DocNameI -> Unicode -> Qualification -> (Html, Html, Html)
-ppShortConstrParts summary dataInst con unicode qual = case con of
-  ConDeclH98{} -> case con_details con of
-    PrefixCon args ->
-      (header_ unicode qual +++ hsep (ppOcc
-            : map (ppLParendType unicode qual HideEmptyContexts) args), noHtml, noHtml)
-    RecCon (L _ fields) ->
-      (header_ unicode qual +++ ppOcc <+> char '{',
-       doRecordFields fields,
-       char '}')
-    InfixCon arg1 arg2 ->
-      (header_ unicode qual +++ hsep [ppLParendType unicode qual HideEmptyContexts arg1,
-            ppOccInfix, ppLParendType unicode qual HideEmptyContexts arg2],
-       noHtml, noHtml)
-
-  ConDeclGADT {} -> (ppOcc <+> dcolon unicode <+> ppLType unicode qual HideEmptyContexts resTy,noHtml,noHtml)
-
-  where
-    resTy = hsib_body (con_type con)
-
-    doRecordFields fields = shortSubDecls dataInst (map (ppShortField summary unicode qual) (map unLoc fields))
-
-    header_  = ppConstrHdr forall_ tyVars context
-    occ        = map (nameOccName . getName . unLoc) $ getConNames con
-
-    ppOcc      = case occ of
-      [one] -> ppBinder summary one
-      _     -> hsep (punctuate comma (map (ppBinder summary) occ))
+ppShortConstrParts summary dataInst con unicode qual
+  = case con of
+      ConDeclH98{ con_args = det
+                , con_ex_tvs = vars
+                , con_mb_cxt = cxt
+                } -> let tyVars = map (getName . hsLTyVarName) vars
+                         context = unLoc (fromMaybe (noLoc []) cxt)
+                         forall_ = False
+                         header_ = ppConstrHdr forall_ tyVars context unicode qual
+                     in case det of
+
+        -- Prefix constructor, e.g. 'Just a'
+        PrefixCon args ->
+          ( header_ +++ hsep (ppOcc : map (ppLParendType unicode qual HideEmptyContexts) args)
+          , noHtml
+          , noHtml
+          )
 
-    ppOccInfix = case occ of
-      [one] -> ppBinderInfix summary one
-      _     -> hsep (punctuate comma (map (ppBinderInfix summary) occ))
+        -- Record constructor, e.g. 'Identity { runIdentity :: a }'
+        RecCon (L _ fields) ->
+          ( header_ +++ ppOcc <+> char '{'
+          , shortSubDecls dataInst [ ppShortField summary unicode qual field
+                                   | L _ field <- fields
+                                   ]
+          , char '}'
+          )
 
-    ltvs     = fromMaybe (HsQTvs PlaceHolder [] PlaceHolder) (con_qvars con)
-    tyVars   = tyvarNames ltvs
-    lcontext = fromMaybe (noLoc []) (con_cxt con)
-    context  = unLoc lcontext
-    forall_  = False
+        -- Infix constructor, e.g. 'a :| [a]'
+        InfixCon arg1 arg2 ->
+          ( header_ +++ hsep [ ppLParendType unicode qual HideEmptyContexts arg1
+                             , ppOccInfix
+                             , ppLParendType unicode qual HideEmptyContexts arg2
+                             ]
+          , noHtml
+          , noHtml
+          )
 
+      -- GADT constructor, e.g. 'Foo :: Int -> Foo'
+      ConDeclGADT {} ->
+          ( hsep [ ppOcc, dcolon unicode, ppLType unicode qual HideEmptyContexts (getGADTConType con) ]
+          , noHtml
+          , noHtml
+          )
+      XConDecl {} -> panic "haddock:ppShortConstrParts"
 
--- ppConstrHdr is for (non-GADT) existentials constructors' syntax
-ppConstrHdr :: Bool -> [Name] -> HsContext DocNameI -> Unicode
-            -> Qualification -> Html
-ppConstrHdr forall_ tvs ctxt unicode qual
- = (if null tvs then noHtml else ppForall)
-   +++
-   (if null ctxt then noHtml
-    else ppContextNoArrow ctxt unicode qual HideEmptyContexts
-         <+> darrow unicode +++ toHtml " ")
   where
-    ppForall | forall_   = forallSymbol unicode <+> hsep (map (ppName Prefix) tvs)
-                           <+> toHtml ". "
-             | otherwise = noHtml
+    occ        = map (nameOccName . getName . unLoc) $ getConNames con
+    ppOcc      = hsep (punctuate comma (map (ppBinder summary) occ))
+    ppOccInfix = hsep (punctuate comma (map (ppBinderInfix summary) occ))
 
+
+-- | Pretty print an expanded constructor
 ppSideBySideConstr :: [(DocName, DocForDecl DocName)] -> [(DocName, Fixity)]
-                   -> Unicode -> Maybe Package -> Qualification -> LConDecl DocNameI -> SubDecl
+                   -> Unicode -> Maybe Package -> Qualification
+                   -> LConDecl DocNameI -- ^ constructor declaration to print
+                   -> SubDecl
 ppSideBySideConstr subdocs fixities unicode pkg qual (L _ con)
- = (decl, mbDoc, fieldPart)
+ = ( decl       -- Constructor header (name, fixity)
+   , mbDoc      -- Docs on the whole constructor
+   , fieldPart  -- Information on the fields (or arguments, if they have docs)
+   )
  where
-    decl = case con of
-      ConDeclH98{} -> case con_details con of
-        PrefixCon args ->
-          hsep ((header_ +++ ppOcc)
-            : map (ppLParendType unicode qual HideEmptyContexts) args)
-          <+> fixity
+    -- Find the name of a constructors in the decl (`getConName` always returns a non-empty list)
+    aConName = unLoc (head (getConNames con))
 
-        RecCon _ -> header_ +++ ppOcc <+> fixity
+    fixity   = ppFixities fixities qual
+    occ      = map (nameOccName . getName . unLoc) $ getConNames con
 
-        InfixCon arg1 arg2 ->
-          hsep [header_ +++ ppLParendType unicode qual HideEmptyContexts arg1,
-            ppOccInfix,
-            ppLParendType unicode qual HideEmptyContexts arg2]
-          <+> fixity
+    ppOcc      = hsep (punctuate comma (map (ppBinder False) occ))
+    ppOccInfix = hsep (punctuate comma (map (ppBinderInfix False) occ))
 
-      ConDeclGADT{} -> doGADTCon resTy
+    -- Extract out the map of of docs corresponding to the constructors arguments
+    argDocs = maybe Map.empty snd (lookup aConName subdocs)
+    hasArgDocs = not $ Map.null argDocs
 
-    resTy = hsib_body (con_type con)
+    decl = case con of
+      ConDeclH98{ con_args = det
+                , con_ex_tvs = vars
+                , con_mb_cxt = cxt
+                } -> let tyVars = map (getName . hsLTyVarName) vars
+                         context = unLoc (fromMaybe (noLoc []) cxt)
+                         forall_ = False
+                         header_ = ppConstrHdr forall_ tyVars context unicode qual
+                     in case det of
+        -- Prefix constructor, e.g. 'Just a'
+        PrefixCon args
+          | hasArgDocs -> header_ +++ ppOcc <+> fixity
+          | otherwise -> hsep [ header_ +++ ppOcc
+                              , hsep (map (ppLParendType unicode qual HideEmptyContexts) args)
+                              , fixity
+                              ]
+
+        -- Record constructor, e.g. 'Identity { runIdentity :: a }'
+        RecCon _ -> header_ +++ ppOcc <+> fixity
+
+        -- Infix constructor, e.g. 'a :| [a]'
+        InfixCon arg1 arg2
+          | hasArgDocs -> header_ +++ ppOcc <+> fixity
+          | otherwise -> hsep [ header_ +++ ppLParendType unicode qual HideEmptyContexts arg1
+                              , ppOccInfix
+                              , ppLParendType unicode qual HideEmptyContexts arg2
+                              , fixity
+                              ]
+
+      -- GADT constructor, e.g. 'Foo :: Int -> Foo'
+      ConDeclGADT{}
+          | hasArgDocs || not (null fieldPart) -> ppOcc <+> fixity
+          | otherwise -> hsep [ ppOcc
+                              , dcolon unicode
+                              -- ++AZ++ make this prepend "{..}" when it is a record style GADT
+                              , ppLType unicode qual HideEmptyContexts (getGADTConType con)
+                              , fixity
+                              ]
+      XConDecl{} -> panic "haddock:ppSideBySideConstr"
+
+    fieldPart = case (con, getConArgs con) of
+        -- Record style GADTs
+        (ConDeclGADT{}, RecCon _)            -> [ doConstrArgsWithDocs [] ]
+
+        -- Regular record declarations
+        (_, RecCon (L _ fields))             -> [ doRecordFields fields ]
+
+        -- Any GADT or a regular H98 prefix data constructor
+        (_, PrefixCon args)     | hasArgDocs -> [ doConstrArgsWithDocs args ]
+
+        -- An infix H98 data constructor
+        (_, InfixCon arg1 arg2) | hasArgDocs -> [ doConstrArgsWithDocs [arg1,arg2] ]
 
-    fieldPart = case getConDetails con of
-        RecCon (L _ fields) -> [doRecordFields fields]
         _ -> []
 
     doRecordFields fields = subFields pkg qual
       (map (ppSideBySideField subdocs unicode qual) (map unLoc fields))
 
-    doGADTCon :: Located (HsType DocNameI) -> Html
-    doGADTCon ty = ppOcc <+> dcolon unicode
-        -- ++AZ++ make this prepend "{..}" when it is a record style GADT
-        <+> ppLType unicode qual HideEmptyContexts ty
-        <+> fixity
-
-    fixity  = ppFixities fixities qual
-    header_ = ppConstrHdr forall_ tyVars context unicode qual
-    occ       = map (nameOccName . getName . unLoc) $ getConNames con
-
-    ppOcc     = case occ of
-      [one] -> ppBinder False one
-      _     -> hsep (punctuate comma (map (ppBinder False) occ))
+    doConstrArgsWithDocs args = subFields pkg qual $ case con of
+      ConDeclH98{} ->
+        [ (ppLParendType unicode qual HideEmptyContexts arg, mdoc, [])
+        | (i, arg) <- zip [0..] args
+        , let mdoc = Map.lookup i argDocs
+        ]
+      ConDeclGADT{} ->
+        ppSubSigLike unicode qual (unLoc (getGADTConType con))
+                     argDocs subdocs (dcolon unicode) HideEmptyContexts
+      XConDecl{} -> panic "haddock:doConstrArgsWithDocs"
 
-    ppOccInfix = case occ of
-      [one] -> ppBinderInfix False one
-      _     -> hsep (punctuate comma (map (ppBinderInfix False) occ))
-
-    tyVars  = tyvarNames (fromMaybe (HsQTvs PlaceHolder [] PlaceHolder) (con_qvars con))
-    context = unLoc (fromMaybe (noLoc []) (con_cxt con))
-    forall_ = False
     -- 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.
     mbDoc = lookup (unLoc $ head $ getConNames con) subdocs >>=
             combineDocumentation . fst
 
 
+-- ppConstrHdr is for (non-GADT) existentials constructors' syntax
+ppConstrHdr :: Bool               -- ^ print explicit foralls
+            -> [Name]             -- ^ type variables
+            -> HsContext DocNameI -- ^ context
+            -> Unicode -> Qualification -> Html
+ppConstrHdr forall_ tvs ctxt unicode qual = ppForall +++ ppCtxt
+  where
+    ppForall
+      | null tvs || not forall_ = noHtml
+      | otherwise = forallSymbol unicode
+                      <+> hsep (map (ppName Prefix) tvs)
+                      <+> toHtml ". "
+
+    ppCtxt
+      | null ctxt = noHtml
+      | otherwise = ppContextNoArrow ctxt unicode qual HideEmptyContexts
+                      <+> darrow unicode +++ toHtml " "
+
+
+-- | Pretty-print a record field
 ppSideBySideField :: [(DocName, DocForDecl DocName)] -> Unicode -> Qualification
                   -> ConDeclField DocNameI -> SubDecl
-ppSideBySideField subdocs unicode qual (ConDeclField names ltype _) =
-  ( hsep (punctuate comma (map ((ppBinder False) . rdrNameOcc . unLoc . rdrNameFieldOcc . unLoc) names))
+ppSideBySideField subdocs unicode qual (ConDeclField _ names ltype _) =
+  ( hsep (punctuate comma [ ppBinder False (rdrNameOcc field)
+                          | L _ name <- names
+                          , let field = (unLoc . rdrNameFieldOcc) name
+                          ])
       <+> dcolon unicode
       <+> ppLType unicode qual HideEmptyContexts ltype
   , mbDoc
@@ -900,13 +1012,49 @@ ppSideBySideField subdocs unicode qual (ConDeclField names ltype _) =
   where
     -- 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 (selectorFieldOcc $ unLoc $ head names) subdocs >>= combineDocumentation . fst
+    mbDoc = lookup (extFieldOcc $ unLoc $ head names) subdocs >>= combineDocumentation . fst
+ppSideBySideField _ _ _ (XConDeclField _) = panic "haddock:ppSideBySideField"
 
 
 ppShortField :: Bool -> Unicode -> Qualification -> ConDeclField DocNameI -> Html
-ppShortField summary unicode qual (ConDeclField names ltype _)
+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 _) = panic "haddock:ppShortField"
+
+
+-- | Pretty print an expanded pattern (for bundled patterns)
+ppSideBySidePat :: [(DocName, Fixity)] -> Unicode -> Qualification
+                   -> [Located DocName]    -- ^ pattern name(s)
+                   -> LHsSigType DocNameI  -- ^ type of pattern(s)
+                   -> DocForDecl DocName   -- ^ doc map
+                   -> SubDecl
+ppSideBySidePat fixities unicode qual lnames typ (doc, argDocs) =
+  ( decl
+  , combineDocumentation doc
+  , fieldPart
+  )
+  where
+    hasArgDocs = not $ Map.null argDocs
+    fixity = ppFixities fixities qual
+    ppOcc = hsep (punctuate comma (map (ppBinder False . getOccName) lnames))
+
+    decl | hasArgDocs = keyword "pattern" <+> ppOcc <+> fixity
+         | otherwise = hsep [ keyword "pattern"
+                            , ppOcc
+                            , dcolon unicode
+                            , ppPatSigType unicode qual (hsSigType typ)
+                            , fixity
+                            ]
+
+    fieldPart
+      | not hasArgDocs = []
+      | otherwise = [ subFields Nothing qual (ppSubSigLike unicode qual (unLoc patTy)
+                                                        argDocs [] (dcolon unicode)
+                                                        emptyCtxt) ]
+
+    patTy = hsSigType typ
+    emptyCtxt = patSigContext patTy
 
 
 -- | Print the LHS of a data\/newtype declaration.
@@ -987,11 +1135,12 @@ ppParendType unicode qual emptyCtxts ty = ppr_mono_ty pREC_CON ty unicode qual e
 ppFunLhType  unicode qual emptyCtxts ty = ppr_mono_ty pREC_FUN ty unicode qual emptyCtxts
 
 ppHsTyVarBndr :: Unicode -> Qualification -> HsTyVarBndr DocNameI -> Html
-ppHsTyVarBndr _       qual (UserTyVar (L _ name)) =
+ppHsTyVarBndr _       qual (UserTyVar _ (L _ name)) =
     ppDocName qual Raw False name
-ppHsTyVarBndr unicode qual (KindedTyVar name kind) =
+ppHsTyVarBndr unicode qual (KindedTyVar _ name kind) =
     parens (ppDocName qual Raw False (unLoc name) <+> dcolon unicode <+>
             ppLKind unicode qual kind)
+ppHsTyVarBndr _ _ (XTyVarBndr _) = error "haddock:ppHsTyVarBndr"
 
 ppLKind :: Unicode -> Qualification -> LHsKind DocNameI -> Html
 ppLKind unicode qual y = ppKind unicode qual (unLoc y)
@@ -999,29 +1148,32 @@ ppLKind unicode qual y = ppKind unicode qual (unLoc y)
 ppKind :: Unicode -> Qualification -> HsKind DocNameI -> Html
 ppKind unicode qual ki = ppr_mono_ty pREC_TOP ki unicode qual HideEmptyContexts
 
-ppPatSigType :: Unicode -> Qualification -> LHsType DocNameI -> Html
-ppPatSigType unicode qual typ =
-  let emptyCtxts =
-        if hasNonEmptyContext typ && isFirstContextEmpty typ
-          then ShowEmptyToplevelContexts
-          else HideEmptyContexts
-  in ppLType unicode qual emptyCtxts typ
+patSigContext :: LHsType name -> HideEmptyContexts
+patSigContext typ | hasNonEmptyContext typ && isFirstContextEmpty typ =  ShowEmptyToplevelContexts
+                  | otherwise = HideEmptyContexts
   where
     hasNonEmptyContext :: LHsType name -> Bool
     hasNonEmptyContext t =
       case unLoc t of
-        HsForAllTy _ s -> hasNonEmptyContext s
-        HsQualTy cxt s -> if null (unLoc cxt) then hasNonEmptyContext s else True
-        HsFunTy _ s -> hasNonEmptyContext s
+        HsForAllTy _ _ s -> hasNonEmptyContext s
+        HsQualTy _ cxt s -> if null (unLoc cxt) then hasNonEmptyContext s else True
+        HsFunTy _ _ s    -> hasNonEmptyContext s
         _ -> False
     isFirstContextEmpty :: LHsType name -> Bool
     isFirstContextEmpty t =
       case unLoc t of
-        HsForAllTy _ s -> isFirstContextEmpty s
-        HsQualTy cxt _ -> null (unLoc cxt)
-        HsFunTy _ s -> isFirstContextEmpty s
+        HsForAllTy _ _ s -> isFirstContextEmpty s
+        HsQualTy _ cxt _ -> null (unLoc cxt)
+        HsFunTy _ _ s    -> isFirstContextEmpty s
         _ -> False
 
+
+-- | Pretty-print a pattern signature (all this does over 'ppLType' is slot in
+-- the right 'HideEmptyContext' value)
+ppPatSigType :: Unicode -> Qualification -> LHsType DocNameI -> Html
+ppPatSigType unicode qual typ =
+  let emptyCtxts = patSigContext typ in ppLType unicode qual emptyCtxts typ
+
 ppForAllPart :: Unicode -> Qualification -> [LHsTyVarBndr DocNameI] -> Html
 ppForAllPart unicode qual tvs = hsep (forallSymbol unicode : ppTyVars unicode qual tvs) +++ dot
 
@@ -1030,50 +1182,50 @@ ppr_mono_lty ctxt_prec ty = ppr_mono_ty ctxt_prec (unLoc ty)
 
 
 ppr_mono_ty :: Int -> HsType DocNameI -> Unicode -> Qualification -> HideEmptyContexts -> Html
-ppr_mono_ty ctxt_prec (HsForAllTy tvs ty) unicode qual emptyCtxts
+ppr_mono_ty ctxt_prec (HsForAllTy _ tvs ty) unicode qual emptyCtxts
   = maybeParen ctxt_prec pREC_FUN $
     ppForAllPart unicode qual tvs <+> ppr_mono_lty pREC_TOP ty unicode qual emptyCtxts
 
-ppr_mono_ty ctxt_prec (HsQualTy ctxt ty) unicode qual emptyCtxts
+ppr_mono_ty ctxt_prec (HsQualTy _ ctxt ty) unicode qual emptyCtxts
   = maybeParen ctxt_prec pREC_FUN $
     ppLContext ctxt unicode qual emptyCtxts <+> ppr_mono_lty pREC_TOP ty unicode qual emptyCtxts
 
 -- UnicodeSyntax alternatives
-ppr_mono_ty _ (HsTyVar _ (L _ name)) True _ _
+ppr_mono_ty _ (HsTyVar _ _ (L _ name)) True _ _
   | getOccString (getName name) == "*"    = toHtml "★"
   | getOccString (getName name) == "(->)" = toHtml "(→)"
 
-ppr_mono_ty _         (HsBangTy b ty)     u q _ = ppBang b +++ ppLParendType u q HideEmptyContexts ty
-ppr_mono_ty _         (HsTyVar _ (L _ name)) _ q _ = ppDocName q Prefix True name
-ppr_mono_ty ctxt_prec (HsFunTy ty1 ty2)   u q e = ppr_fun_ty ctxt_prec ty1 ty2 u q e
-ppr_mono_ty _         (HsTupleTy con tys) u q _ = tupleParens con (map (ppLType u q HideEmptyContexts) tys)
-ppr_mono_ty _         (HsSumTy tys) u q _ = sumParens (map (ppLType u q HideEmptyContexts) tys)
-ppr_mono_ty _         (HsKindSig ty kind) u q e =
+ppr_mono_ty _         (HsBangTy _ b ty)     u q _ = ppBang b +++ ppLParendType u q HideEmptyContexts ty
+ppr_mono_ty _         (HsTyVar _ _ (L _ name)) _ q _ = ppDocName q Prefix True name
+ppr_mono_ty ctxt_prec (HsFunTy _ ty1 ty2)   u q e = ppr_fun_ty ctxt_prec ty1 ty2 u q e
+ppr_mono_ty _         (HsTupleTy _ con tys) u q _ = tupleParens con (map (ppLType u q HideEmptyContexts) tys)
+ppr_mono_ty _         (HsSumTy _ tys) u q _ = sumParens (map (ppLType u q HideEmptyContexts) tys)
+ppr_mono_ty _         (HsKindSig _ ty kind) u q e =
     parens (ppr_mono_lty pREC_TOP ty u q e <+> dcolon u <+> ppLKind u q kind)
-ppr_mono_ty _         (HsListTy ty)       u q _ = brackets (ppr_mono_lty pREC_TOP ty u q HideEmptyContexts)
-ppr_mono_ty _         (HsPArrTy ty)       u q _ = pabrackets (ppr_mono_lty pREC_TOP ty u q HideEmptyContexts)
-ppr_mono_ty ctxt_prec (HsIParamTy (L _ n) ty) u q _ =
+ppr_mono_ty _         (HsListTy _ ty)       u q _ = brackets (ppr_mono_lty pREC_TOP ty u q HideEmptyContexts)
+ppr_mono_ty _         (HsPArrTy _ ty)       u q _ = pabrackets (ppr_mono_lty pREC_TOP ty u q HideEmptyContexts)
+ppr_mono_ty ctxt_prec (HsIParamTy _ (L _ n) ty) u q _ =
     maybeParen ctxt_prec pREC_CTX $ ppIPName n <+> dcolon u <+> ppr_mono_lty pREC_TOP ty u q HideEmptyContexts
 ppr_mono_ty _         (HsSpliceTy {})     _ _ _ = error "ppr_mono_ty HsSpliceTy"
 ppr_mono_ty _         (HsRecTy {})        _ _ _ = toHtml "{..}"
        -- Can now legally occur in ConDeclGADT, the output here is to provide a
        -- placeholder in the signature, which is followed by the field
        -- declarations.
-ppr_mono_ty _         (HsCoreTy {})       _ _ _ = error "ppr_mono_ty HsCoreTy"
-ppr_mono_ty _         (HsExplicitListTy Promoted _ tys) u q _ = promoQuote $ brackets $ hsep $ punctuate comma $ map (ppLType u q HideEmptyContexts) tys
-ppr_mono_ty _         (HsExplicitListTy NotPromoted _ tys) u q _ = brackets $ hsep $ punctuate comma $ map (ppLType u q HideEmptyContexts) tys
+ppr_mono_ty _         (XHsType (NHsCoreTy {})) _ _ _ = error "ppr_mono_ty HsCoreTy"
+ppr_mono_ty _         (HsExplicitListTy _ Promoted tys) u q _ = promoQuote $ brackets $ hsep $ punctuate comma $ map (ppLType u q HideEmptyContexts) tys
+ppr_mono_ty _         (HsExplicitListTy _ NotPromoted tys) u q _ = brackets $ hsep $ punctuate comma $ map (ppLType u q HideEmptyContexts) tys
 ppr_mono_ty _         (HsExplicitTupleTy _ tys) u q _ = promoQuote $ parenList $ map (ppLType u q HideEmptyContexts) tys
 ppr_mono_ty _         (HsAppsTy {})       _ _ _ = error "ppr_mono_ty HsAppsTy"
 
-ppr_mono_ty ctxt_prec (HsEqTy ty1 ty2) unicode qual _
+ppr_mono_ty ctxt_prec (HsEqTy _ ty1 ty2) unicode qual _
   = maybeParen ctxt_prec pREC_CTX $
     ppr_mono_lty pREC_OP ty1 unicode qual HideEmptyContexts <+> char '~' <+> ppr_mono_lty pREC_OP ty2 unicode qual HideEmptyContexts
 
-ppr_mono_ty ctxt_prec (HsAppTy fun_ty arg_ty) unicode qual _
+ppr_mono_ty ctxt_prec (HsAppTy _ fun_ty arg_ty) unicode qual _
   = maybeParen ctxt_prec pREC_CON $
     hsep [ppr_mono_lty pREC_FUN fun_ty unicode qual HideEmptyContexts, ppr_mono_lty pREC_CON arg_ty unicode qual HideEmptyContexts]
 
-ppr_mono_ty ctxt_prec (HsOpTy ty1 op ty2) unicode qual _
+ppr_mono_ty ctxt_prec (HsOpTy _ ty1 op ty2) unicode qual _
   = maybeParen ctxt_prec pREC_FUN $
     ppr_mono_lty pREC_OP ty1 unicode qual HideEmptyContexts <+> ppr_op <+> ppr_mono_lty pREC_OP ty2 unicode qual HideEmptyContexts
   where
@@ -1084,15 +1236,15 @@ ppr_mono_ty ctxt_prec (HsOpTy ty1 op ty2) unicode qual _
         | otherwise = ppr_op'
     ppr_op' = ppLDocName qual Infix op
 
-ppr_mono_ty ctxt_prec (HsParTy ty) unicode qual emptyCtxts
+ppr_mono_ty ctxt_prec (HsParTy _ ty) unicode qual emptyCtxts
 --  = parens (ppr_mono_lty pREC_TOP ty)
   = ppr_mono_lty ctxt_prec ty unicode qual emptyCtxts
 
-ppr_mono_ty ctxt_prec (HsDocTy ty _) unicode qual emptyCtxts
+ppr_mono_ty ctxt_prec (HsDocTy _ ty _) unicode qual emptyCtxts
   = ppr_mono_lty ctxt_prec ty unicode qual emptyCtxts
 
 ppr_mono_ty _ (HsWildCardTy (AnonWildCard _)) _ _ _ = char '_'
-ppr_mono_ty _ (HsTyLit n) _ _ _ = ppr_tylit n
+ppr_mono_ty _ (HsTyLit _ n) _ _ _ = ppr_tylit n
 
 ppr_tylit :: HsTyLit -> Html
 ppr_tylit (HsNumTy _ n) = toHtml (show n)
diff --git a/haddock-api/src/Haddock/Backends/Xhtml/Utils.hs b/haddock-api/src/Haddock/Backends/Xhtml/Utils.hs
index a75c4b9a..7fbaec6d 100644
--- a/haddock-api/src/Haddock/Backends/Xhtml/Utils.hs
+++ b/haddock-api/src/Haddock/Backends/Xhtml/Utils.hs
@@ -110,7 +110,7 @@ renderToString debug html
 
 hsep :: [Html] -> Html
 hsep [] = noHtml
-hsep htmls = foldr1 (\a b -> a+++" "+++b) htmls
+hsep htmls = foldr1 (<+>) htmls
 
 -- | Concatenate a series of 'Html' values vertically, with linebreaks in between.
 vcat :: [Html] -> Html
@@ -232,4 +232,4 @@ collapseToggle id_ classes = [ theclass cs, strAttr "data-details-id" id_ ]
 -- and displays a control.
 collapseControl :: String -> String -> [HtmlAttr]
 collapseControl id_ classes = collapseToggle id_ cs
-  where cs = unwords (words classes ++ ["details-toggle-control"])
\ No newline at end of file
+  where cs = unwords (words classes ++ ["details-toggle-control"])