Restore Trees That Grow reverted commits

The following commits were reverted prior to the release of GHC 8.4.1,
because the time to derive Data instances was too long [1].

 438dd1cbba13d35f3452b4dcef3f94ce9a216905 Phab:D4147
 e3ec2e7ae94524ebd111963faf34b84d942265b4 Phab:D4177
 47ad6578ea460999b53eb4293c3a3b3017a56d65 Phab:D4186

The work is continuing, as the minimum bootstrap compiler is now
GHC 8.2.1, and this allows Plan B[2] for instances to be used.  This
will land in a following commit.

Updates Haddock submodule

[1] https://ghc.haskell.org/trac/ghc/wiki/ImplementingTreesThatGrow/Instances
[2] https://ghc.haskell.org/trac/ghc/wiki/ImplementingTreesThatGrow/Instances#PLANB

1 files changed, 33 insertions, 32 deletions

diff --git a/compiler/hsSyn/HsDecls.hs b/compiler/hsSyn/HsDecls.hs
index f29e7e2b0a..54314a9048 100644
--- a/compiler/hsSyn/HsDecls.hs
+++ b/compiler/hsSyn/HsDecls.hs
@@ -99,7 +99,7 @@ import Name
 import BasicTypes
 import Coercion
 import ForeignCall
-import PlaceHolder ( PlaceHolder(..) )
+import PlaceHolder ( PlaceHolder, placeHolder )
 import HsExtension
 import NameSet
 
@@ -147,7 +147,7 @@ data HsDecl id
                                    -- (Includes quasi-quotes)
   | DocD        (DocDecl)          -- ^ Documentation comment declaration
   | RoleAnnotD  (RoleAnnotDecl id) -- ^ Role annotation declaration
-deriving instance (DataId id) => Data (HsDecl id)
+deriving instance (DataIdLR id id) => Data (HsDecl id)
 
 
 -- NB: all top-level fixity decls are contained EITHER
@@ -193,9 +193,9 @@ data HsGroup id
 
         hs_docs   :: [LDocDecl]
   }
-deriving instance (DataId id) => Data (HsGroup id)
+deriving instance (DataIdLR id id) => Data (HsGroup id)
 
-emptyGroup, emptyRdrGroup, emptyRnGroup :: HsGroup a
+emptyGroup, emptyRdrGroup, emptyRnGroup :: HsGroup (GhcPass a)
 emptyRdrGroup = emptyGroup { hs_valds = emptyValBindsIn }
 emptyRnGroup  = emptyGroup { hs_valds = emptyValBindsOut }
 
@@ -210,7 +210,8 @@ emptyGroup = HsGroup { hs_tyclds = [],
                        hs_splcds = [],
                        hs_docs = [] }
 
-appendGroups :: HsGroup a -> HsGroup a -> HsGroup a
+appendGroups :: HsGroup (GhcPass a) -> HsGroup (GhcPass a)
+             -> HsGroup (GhcPass a)
 appendGroups
     HsGroup {
         hs_valds  = val_groups1,
@@ -311,7 +312,7 @@ data SpliceDecl id
   = SpliceDecl                  -- Top level splice
         (Located (HsSplice id))
         SpliceExplicitFlag
-deriving instance (DataId id) => Data (SpliceDecl id)
+deriving instance (DataIdLR id id) => Data (SpliceDecl id)
 
 instance (p ~ GhcPass pass, OutputableBndrId p)
        => Outputable (SpliceDecl p) where
@@ -534,7 +535,7 @@ data TyClDecl pass
 
         -- For details on above see note [Api annotations] in ApiAnnotation
 
-deriving instance (DataId id) => Data (TyClDecl id)
+deriving instance (DataIdLR id id) => Data (TyClDecl id)
 
 
 -- Simple classifiers for TyClDecl
@@ -629,9 +630,9 @@ hsDeclHasCusk (SynDecl { tcdTyVars = tyvars, tcdRhs = rhs })
   = hsTvbAllKinded tyvars && rhs_annotated rhs
   where
     rhs_annotated (L _ ty) = case ty of
-      HsParTy lty  -> rhs_annotated lty
-      HsKindSig {} -> True
-      _            -> False
+      HsParTy _ lty  -> rhs_annotated lty
+      HsKindSig {}   -> True
+      _              -> False
 hsDeclHasCusk (DataDecl { tcdDataCusk = cusk }) = cusk
 hsDeclHasCusk (ClassDecl { tcdTyVars = tyvars }) = hsTvbAllKinded tyvars
 
@@ -778,7 +779,7 @@ data TyClGroup pass  -- See Note [TyClGroups and dependency analysis]
   = TyClGroup { group_tyclds :: [LTyClDecl pass]
               , group_roles  :: [LRoleAnnotDecl pass]
               , group_instds :: [LInstDecl pass] }
-deriving instance (DataId id) => Data (TyClGroup id)
+deriving instance (DataIdLR id id) => Data (TyClGroup id)
 
 emptyTyClGroup :: TyClGroup pass
 emptyTyClGroup = TyClGroup [] [] []
@@ -894,7 +895,7 @@ data FamilyResultSig pass = -- see Note [FamilyResultSig]
 
   -- For details on above see note [Api annotations] in ApiAnnotation
 
-deriving instance (DataId pass) => Data (FamilyResultSig pass)
+deriving instance (DataIdLR pass pass) => Data (FamilyResultSig pass)
 
 -- | Located type Family Declaration
 type LFamilyDecl pass = Located (FamilyDecl pass)
@@ -917,7 +918,7 @@ data FamilyDecl pass = FamilyDecl
 
   -- For details on above see note [Api annotations] in ApiAnnotation
 
-deriving instance (DataId id) => Data (FamilyDecl id)
+deriving instance (DataIdLR id id) => Data (FamilyDecl id)
 
 -- | Located Injectivity Annotation
 type LInjectivityAnn pass = Located (InjectivityAnn pass)
@@ -944,7 +945,7 @@ data FamilyInfo pass
      -- | 'Nothing' if we're in an hs-boot file and the user
      -- said "type family Foo x where .."
   | ClosedTypeFamily (Maybe [LTyFamInstEqn pass])
-deriving instance (DataId pass) => Data (FamilyInfo pass)
+deriving instance (DataIdLR pass pass) => Data (FamilyInfo pass)
 
 -- | Does this family declaration have a complete, user-supplied kind signature?
 famDeclHasCusk :: Maybe Bool
@@ -960,7 +961,7 @@ famDeclHasCusk mb_class_cusk _ = mb_class_cusk `orElse` True
 -- | Does this family declaration have user-supplied return kind signature?
 hasReturnKindSignature :: FamilyResultSig a -> Bool
 hasReturnKindSignature NoSig                          = False
-hasReturnKindSignature (TyVarSig (L _ (UserTyVar _))) = False
+hasReturnKindSignature (TyVarSig (L _ (UserTyVar{}))) = False
 hasReturnKindSignature _                              = True
 
 -- | Maybe return name of the result type variable
@@ -1052,7 +1053,7 @@ data HsDataDefn pass   -- The payload of a data type defn
 
              -- For details on above see note [Api annotations] in ApiAnnotation
    }
-deriving instance (DataId id) => Data (HsDataDefn id)
+deriving instance (DataIdLR id id) => Data (HsDataDefn id)
 
 -- | Haskell Deriving clause
 type HsDeriving pass = Located [LHsDerivingClause pass]
@@ -1088,7 +1089,7 @@ data HsDerivingClause pass
       --
       -- should produce a derived instance for @C [a] (T b)@.
     }
-deriving instance (DataId id) => Data (HsDerivingClause id)
+deriving instance (DataIdLR id id) => Data (HsDerivingClause id)
 
 instance (p ~ GhcPass pass, OutputableBndrId p)
        => Outputable (HsDerivingClause p) where
@@ -1182,7 +1183,7 @@ data ConDecl pass
       , con_doc       :: Maybe LHsDocString
           -- ^ A possible Haddock comment.
       }
-deriving instance (DataId pass) => Data (ConDecl pass)
+deriving instance (DataIdLR pass pass) => Data (ConDecl pass)
 
 {- Note [GADT abstract syntax]
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
@@ -1415,7 +1416,7 @@ newtype TyFamInstDecl pass = TyFamInstDecl { tfid_eqn :: TyFamInstEqn pass }
     --           'ApiAnnotation.AnnInstance',
 
     -- For details on above see note [Api annotations] in ApiAnnotation
-deriving instance DataId pass => Data (TyFamInstDecl pass)
+deriving instance DataIdLR pass pass => Data (TyFamInstDecl pass)
 
 ----------------- Data family instances -------------
 
@@ -1433,7 +1434,7 @@ newtype DataFamInstDecl pass
     --           'ApiAnnotation.AnnClose'
 
     -- For details on above see note [Api annotations] in ApiAnnotation
-deriving instance DataId pass => Data (DataFamInstDecl pass)
+deriving instance DataIdLR pass pass => Data (DataFamInstDecl pass)
 
 ----------------- Family instances (common types) -------------
 
@@ -1493,7 +1494,7 @@ data ClsInstDecl pass
     --           'ApiAnnotation.AnnOpen','ApiAnnotation.AnnClose',
 
     -- For details on above see note [Api annotations] in ApiAnnotation
-deriving instance (DataId id) => Data (ClsInstDecl id)
+deriving instance (DataIdLR id id) => Data (ClsInstDecl id)
 
 
 ----------------- Instances of all kinds -------------
@@ -1509,7 +1510,7 @@ data InstDecl pass  -- Both class and family instances
       { dfid_inst :: DataFamInstDecl pass }
   | TyFamInstD              -- type family instance
       { tfid_inst :: TyFamInstDecl pass }
-deriving instance (DataId id) => Data (InstDecl id)
+deriving instance (DataIdLR id id) => Data (InstDecl id)
 
 instance (p ~ GhcPass pass, OutputableBndrId p)
        => Outputable (TyFamInstDecl p) where
@@ -1679,7 +1680,7 @@ data DerivDecl pass = DerivDecl
 
   -- For details on above see note [Api annotations] in ApiAnnotation
         }
-deriving instance (DataId pass) => Data (DerivDecl pass)
+deriving instance (DataIdLR pass pass) => Data (DerivDecl pass)
 
 instance (p ~ GhcPass pass, OutputableBndrId p)
        => Outputable (DerivDecl p) where
@@ -1714,7 +1715,7 @@ data DefaultDecl pass
         --          'ApiAnnotation.AnnOpen','ApiAnnotation.AnnClose'
 
         -- For details on above see note [Api annotations] in ApiAnnotation
-deriving instance (DataId pass) => Data (DefaultDecl pass)
+deriving instance (DataIdLR pass pass) => Data (DefaultDecl pass)
 
 instance (p ~ GhcPass pass, OutputableBndrId p)
        => Outputable (DefaultDecl p) where
@@ -1758,7 +1759,7 @@ data ForeignDecl pass
 
         -- For details on above see note [Api annotations] in ApiAnnotation
 
-deriving instance (DataId pass) => Data (ForeignDecl pass)
+deriving instance (DataIdLR pass pass) => Data (ForeignDecl pass)
 {-
     In both ForeignImport and ForeignExport:
         sig_ty is the type given in the Haskell code
@@ -1769,10 +1770,10 @@ deriving instance (DataId pass) => Data (ForeignDecl pass)
 -}
 
 noForeignImportCoercionYet :: PlaceHolder
-noForeignImportCoercionYet = PlaceHolder
+noForeignImportCoercionYet = placeHolder
 
 noForeignExportCoercionYet :: PlaceHolder
-noForeignExportCoercionYet = PlaceHolder
+noForeignExportCoercionYet = placeHolder
 
 -- Specification Of an imported external entity in dependence on the calling
 -- convention
@@ -1875,7 +1876,7 @@ type LRuleDecls pass = Located (RuleDecls pass)
 -- | Rule Declarations
 data RuleDecls pass = HsRules { rds_src   :: SourceText
                               , rds_rules :: [LRuleDecl pass] }
-deriving instance (DataId pass) => Data (RuleDecls pass)
+deriving instance (DataIdLR pass pass) => Data (RuleDecls pass)
 
 -- | Located Rule Declaration
 type LRuleDecl pass = Located (RuleDecl pass)
@@ -1901,7 +1902,7 @@ data RuleDecl pass
         --           'ApiAnnotation.AnnEqual',
 
         -- For details on above see note [Api annotations] in ApiAnnotation
-deriving instance (DataId pass) => Data (RuleDecl pass)
+deriving instance (DataIdLR pass pass) => Data (RuleDecl pass)
 
 flattenRuleDecls :: [LRuleDecls pass] -> [LRuleDecl pass]
 flattenRuleDecls decls = concatMap (rds_rules . unLoc) decls
@@ -1918,7 +1919,7 @@ data RuleBndr pass
         --     'ApiAnnotation.AnnDcolon','ApiAnnotation.AnnClose'
 
         -- For details on above see note [Api annotations] in ApiAnnotation
-deriving instance (DataId pass) => Data (RuleBndr pass)
+deriving instance (DataIdLR pass pass) => Data (RuleBndr pass)
 
 collectRuleBndrSigTys :: [RuleBndr pass] -> [LHsSigWcType pass]
 collectRuleBndrSigTys bndrs = [ty | RuleBndrSig _ ty <- bndrs]
@@ -2009,7 +2010,7 @@ data VectDecl pass
       (LHsSigType pass)
   | HsVectInstOut               -- post type-checking (always SCALAR) !!!FIXME: should be superfluous now
       ClsInst
-deriving instance (DataId pass) => Data (VectDecl pass)
+deriving instance (DataIdLR pass pass) => Data (VectDecl pass)
 
 lvectDeclName :: NamedThing (IdP pass) => LVectDecl pass -> Name
 lvectDeclName (L _ (HsVect _       (L _ name) _))    = getName name
@@ -2147,7 +2148,7 @@ data AnnDecl pass = HsAnnotation
       --           'ApiAnnotation.AnnClose'
 
       -- For details on above see note [Api annotations] in ApiAnnotation
-deriving instance (DataId pass) => Data (AnnDecl pass)
+deriving instance (DataIdLR pass pass) => Data (AnnDecl pass)
 
 instance (p ~ GhcPass pass, OutputableBndrId p) => Outputable (AnnDecl p) where
     ppr (HsAnnotation _ provenance expr)