%
-% (c) The AQUA Project, Glasgow University, 1996
+% (c) The AQUA Project, Glasgow University, 1996-1998
%
\section[TcTyClsDecls]{Typecheck type and class declarations}
\begin{code}
-#include "HsVersions.h"
-
module TcTyClsDecls (
tcTyAndClassDecls1
) where
-import Ubiq{-uitous-}
+#include "HsVersions.h"
-import HsSyn ( TyDecl(..), ConDecl(..), BangType(..),
- ClassDecl(..), MonoType(..), PolyType(..),
- Sig(..), MonoBinds, Fake, InPat )
-import RnHsSyn ( RenamedTyDecl(..), RenamedClassDecl(..) )
+import HsSyn ( HsDecl(..), TyDecl(..), ClassDecl(..),
+ HsType(..), HsTyVar,
+ ConDecl(..), ConDetails(..), BangType(..),
+ Sig(..),
+ hsDeclName
+ )
+import RnHsSyn ( RenamedHsDecl )
+import RnEnv ( listTyCon_name, tupleTyCon_name ) -- ToDo: move these
+import BasicTypes ( RecFlag(..), Arity )
import TcMonad
-import Inst ( InstanceMapper(..) )
+import Inst ( InstanceMapper )
import TcClassDcl ( tcClassDecl1 )
-import TcEnv ( tcExtendTyConEnv, tcExtendClassEnv,
- tcExtendGlobalValEnv, tcExtendKindEnv,
- tcTyVarScope, tcGetEnv )
-import TcKind ( TcKind, newKindVars )
+import TcEnv ( TcIdOcc(..), GlobalValueEnv, tcExtendTyConEnv, tcExtendClassEnv )
+import TcType ( TcKind, newKindVar, newKindVars, kindToTcKind )
import TcTyDecls ( tcTyDecl )
+import TcMonoType ( tcTyVarScope )
+import TyCon ( tyConKind, tyConArity, isSynTyCon )
+import Class ( Class, classBigSig )
+import Var ( tyVarKind )
import Bag
-import Class ( Class(..), getClassSelIds )
-import Digraph ( findSCCs, SCC(..) )
-import Name ( Name, isTyConName )
-import PprStyle
-import Pretty
-import UniqSet ( UniqSet(..), emptyUniqSet,
- singletonUniqSet, unionUniqSets,
+import Digraph ( stronglyConnComp, SCC(..) )
+import Name ( Name, NamedThing(..), getSrcLoc, isTvOcc, nameOccName )
+import Outputable
+import Maybes ( mapMaybe )
+import UniqSet ( UniqSet, emptyUniqSet,
+ unitUniqSet, unionUniqSets,
unionManyUniqSets, uniqSetToList )
import SrcLoc ( SrcLoc )
-import TyCon ( TyCon, getTyConDataCons )
-import Unique ( Unique )
-import Util ( panic, pprTrace )
+import TyCon ( TyCon )
+import Unique ( Unique, Uniquable(..) )
+import Util ( panic{-, pprTrace-} )
\end{code}
The main function
~~~~~~~~~~~~~~~~~
\begin{code}
-data Decl = TyD RenamedTyDecl | ClD RenamedClassDecl
-
-tcTyAndClassDecls1 :: InstanceMapper
- -> Bag RenamedTyDecl -> Bag RenamedClassDecl
+tcTyAndClassDecls1 :: GlobalValueEnv -> InstanceMapper -- Knot tying stuff
+ -> [RenamedHsDecl]
-> TcM s (TcEnv s)
-tcTyAndClassDecls1 inst_mapper rnty_decls rncls_decls
- = sortByDependency syn_decls cls_decls decls `thenTc` \ groups ->
- tcGroups inst_mapper groups
- where
- cls_decls = mapBag ClD rncls_decls
- ty_decls = mapBag TyD rnty_decls
- syn_decls = filterBag is_syn_decl ty_decls
- decls = ty_decls `unionBags` cls_decls
-
- is_syn_decl (TyD (TySynonym _ _ _ _)) = True
- is_syn_decl _ = False
+tcTyAndClassDecls1 unf_env inst_mapper decls
+ = sortByDependency decls `thenTc` \ groups ->
+ tcGroups unf_env inst_mapper groups
-tcGroups inst_mapper []
- = tcGetEnv `thenNF_Tc` \ env ->
+tcGroups unf_env inst_mapper []
+ = tcGetEnv `thenNF_Tc` \ env ->
returnTc env
-tcGroups inst_mapper (group:groups)
- = tcGroup inst_mapper group `thenTc` \ new_env ->
+tcGroups unf_env inst_mapper (group:groups)
+ = tcGroup unf_env inst_mapper group `thenTc` \ (group_tycons, group_classes) ->
-- Extend the environment using the new tycons and classes
- tcSetEnv new_env $
+ tcExtendTyConEnv [(getName tycon, (kindToTcKind (tyConKind tycon),
+ if isSynTyCon tycon then Just (tyConArity tycon) else Nothing,
+ tycon))
+ | tycon <- group_tycons] $
+
+ tcExtendClassEnv [(getName clas, (classKind clas, clas))
+ | clas <- group_classes] $
+
-- Do the remaining groups
- tcGroups inst_mapper groups
+ tcGroups unf_env inst_mapper groups
+ where
+ classKind clas = map (kindToTcKind . tyVarKind) tyvars
+ where
+ (tyvars, _, _, _, _) = classBigSig clas
\end{code}
Dealing with a group
~~~~~~~~~~~~~~~~~~~~
-\begin{code}
-tcGroup :: InstanceMapper -> Bag Decl -> TcM s (TcEnv s)
-tcGroup inst_mapper decls
- = fixTc ( \ ~(tycons,classes,_) ->
- pprTrace "tcGroup: " (ppCat (map (fst.fmt_decl) (bagToList decls))) $
+Notice the uses of @zipLazy@, which makes sure
+that the knot-tied TyVars, TyCons and Classes aren't looked at too early.
+
+
+\begin{code}
+tcGroup :: GlobalValueEnv -> InstanceMapper -> SCC RenamedHsDecl -> TcM s ([TyCon], [Class])
+tcGroup unf_env inst_mapper scc
+ = -- TIE THE KNOT
+ fixTc ( \ ~(rec_tycons, rec_classes) ->
-- EXTEND TYPE AND CLASS ENVIRONMENTS
- -- including their data constructors and class operations
- tcExtendTyConEnv tycons $
- tcExtendClassEnv classes $
- tcExtendGlobalValEnv (concat (map getTyConDataCons tycons)) $
- tcExtendGlobalValEnv (concat (map getClassSelIds classes)) $
+ let
+ mk_tycon_bind (name, arity) = newKindVar `thenNF_Tc` \ kind ->
+ returnNF_Tc (name, (kind, arity, find name rec_tycons))
- -- SNAFFLE ENV TO RETURN
- tcGetEnv `thenNF_Tc` \ final_env ->
+ mk_class_bind (name, arity) = newKindVars arity `thenNF_Tc` \ kinds ->
+ returnNF_Tc (name, (kinds, find name rec_classes))
- -- DEAL WITH TYPE VARIABLES
- tcTyVarScope tyvar_names ( \ tyvars ->
+ find name [] = pprPanic "tcGroup" (ppr name)
+ find name (thing:things) | name == getName thing = thing
+ | otherwise = find name things
- -- MANUFACTURE NEW KINDS, AND EXTEND KIND ENV
- newKindVars (length tycon_names) `thenNF_Tc` \ tycon_kinds ->
- newKindVars (length class_names) `thenNF_Tc` \ class_kinds ->
- tcExtendKindEnv tycon_names tycon_kinds $
- tcExtendKindEnv class_names class_kinds $
+ in
+ mapNF_Tc mk_tycon_bind tycon_names_w_arities `thenNF_Tc` \ tycon_binds ->
+ mapNF_Tc mk_class_bind class_names_w_arities `thenNF_Tc` \ class_binds ->
+ tcExtendTyConEnv tycon_binds $
+ tcExtendClassEnv class_binds $
+ -- DEAL WITH TYPE VARIABLES
+ tcTyVarScope tyvar_names ( \ tyvars ->
-- DEAL WITH THE DEFINITIONS THEMSELVES
- foldBag combine (tcDecl inst_mapper)
- (returnTc (emptyBag, emptyBag))
- decls
- ) `thenTc` \ (tycons,classes) ->
-
- returnTc (bagToList tycons, bagToList classes, final_env)
- ) `thenTc` \ (_, _, final_env) ->
- returnTc final_env
+ foldlTc (tcDecl is_rec_group unf_env inst_mapper) ([], []) decls
+ ) `thenTc` \ (tycons, classes) ->
+ returnTc (tycons, classes)
+ )
where
- (tyvar_names, tycon_names, class_names) = get_binders decls
+ is_rec_group = case scc of
+ AcyclicSCC _ -> NonRecursive
+ CyclicSCC _ -> Recursive
- combine do_a do_b
- = do_a `thenTc` \ (a1,a2) ->
- do_b `thenTc` \ (b1,b2) ->
- returnTc (a1 `unionBags` b1, a2 `unionBags` b2)
+ decls = case scc of
+ AcyclicSCC decl -> [decl]
+ CyclicSCC decls -> decls
+
+ (tyvar_names, tycon_names_w_arities, class_names_w_arities) = get_binders decls
\end{code}
Dealing with one decl
~~~~~~~~~~~~~~~~~~~~~
\begin{code}
-tcDecl :: InstanceMapper
- -> Decl
- -> TcM s (Bag TyCon, Bag Class)
-
-tcDecl inst_mapper (TyD decl)
- = tcTyDecl decl `thenTc` \ tycon ->
- returnTc (unitBag tycon, emptyBag)
-
-tcDecl inst_mapper (ClD decl)
- = tcClassDecl1 inst_mapper decl `thenTc` \ clas ->
- returnTc (emptyBag, unitBag clas)
+tcDecl :: RecFlag -- True => recursive group
+ -> GlobalValueEnv -> InstanceMapper
+ -> ([TyCon], [Class]) -- Accumulating parameter
+ -> RenamedHsDecl
+ -> TcM s ([TyCon], [Class])
+
+tcDecl is_rec_group unf_env inst_mapper (tycons, classes) (TyD decl)
+ = tcTyDecl is_rec_group decl `thenTc` \ tycon ->
+ returnTc (tycon:tycons, classes)
+
+tcDecl is_rec_group unf_env inst_mapper (tycons, classes) (ClD decl)
+ = tcClassDecl1 unf_env inst_mapper decl `thenTc` \ clas ->
+ returnTc (tycons, clas:classes)
\end{code}
Dependency analysis
~~~~~~~~~~~~~~~~~~~
\begin{code}
-sortByDependency :: Bag Decl -> Bag Decl -> Bag Decl -> TcM s [Bag Decl]
-sortByDependency syn_decls cls_decls decls
- = let -- CHECK FOR SYNONYM CYCLES
- syn_sccs = findSCCs mk_edges syn_decls
- syn_cycles = [map fmt_decl (bagToList decls)
- | CyclicSCC decls <- syn_sccs]
-
+sortByDependency :: [RenamedHsDecl] -> TcM s [SCC RenamedHsDecl]
+sortByDependency decls
+ = let -- CHECK FOR CLASS CYCLES
+ cls_sccs = stronglyConnComp (mapMaybe mk_cls_edges decls)
+ cls_cycles = [ decls | CyclicSCC decls <- cls_sccs]
in
- checkTc (null syn_cycles) (typeCycleErr syn_cycles) `thenTc_`
+ checkTc (null cls_cycles) (classCycleErr cls_cycles) `thenTc_`
- let -- CHECK FOR CLASS CYCLES
- cls_sccs = findSCCs mk_edges cls_decls
- cls_cycles = [map fmt_decl (bagToList decls)
- | CyclicSCC decls <- cls_sccs]
+ let -- CHECK FOR SYNONYM CYCLES
+ syn_sccs = stronglyConnComp (filter is_syn_decl edges)
+ syn_cycles = [ decls | CyclicSCC decls <- syn_sccs]
in
- checkTc (null cls_cycles) (classCycleErr cls_cycles) `thenTc_`
+ checkTc (null syn_cycles) (typeCycleErr syn_cycles) `thenTc_`
- -- DO THE MAIN DEPENDENCY ANALYSIS
+ -- DO THE MAIN DEPENDENCY ANALYSIS
let
- decl_sccs = findSCCs mk_edges decls
- scc_bags = map bag_acyclic decl_sccs
+ decl_sccs = stronglyConnComp edges
in
- returnTc (scc_bags)
-
+ returnTc decl_sccs
where
- bag_acyclic (AcyclicSCC scc) = unitBag scc
- bag_acyclic (CyclicSCC sccs) = sccs
+ edges = mapMaybe mk_edges decls
+
+is_syn_decl (TyD (TySynonym _ _ _ _), _, _) = True
+is_syn_decl _ = False
-fmt_decl (TyD (TySynonym name _ _ _)) = (ppr PprForUser name, getSrcLoc name)
-fmt_decl (ClD (ClassDecl _ name _ _ _ _ _)) = (ppr PprForUser name, getSrcLoc name)
+is_cls_decl (ClD _, _, _) = True
+is_cls_decl other = False
\end{code}
Edges in Type/Class decls
~~~~~~~~~~~~~~~~~~~~~~~~~
\begin{code}
-mk_edges (TyD (TyData ctxt name _ condecls _ _ _))
- = (getItsUnique name, set_to_bag (get_ctxt ctxt `unionUniqSets` get_cons condecls))
-mk_edges (TyD (TyNew ctxt name _ condecl _ _ _))
- = (getItsUnique name, set_to_bag (get_ctxt ctxt `unionUniqSets` get_cons condecl))
-mk_edges (TyD (TySynonym name _ rhs _))
- = (getItsUnique name, set_to_bag (get_ty rhs))
-mk_edges (ClD (ClassDecl ctxt name _ sigs _ _ _))
- = (getItsUnique name, set_to_bag (get_ctxt ctxt `unionUniqSets` get_sigs sigs))
-
-get_ctxt ctxt
- = unionManyUniqSets (map (set_name.fst) ctxt)
-
-get_cons cons
- = unionManyUniqSets (map get_con cons)
- where
- get_con (ConDecl _ btys _)
- = unionManyUniqSets (map get_bty btys)
- get_con (ConOpDecl bty1 _ bty2 _)
- = unionUniqSets (get_bty bty1) (get_bty bty2)
- get_con (NewConDecl _ ty _)
- = get_ty ty
- get_con (RecConDecl _ nbtys _)
- = unionManyUniqSets (map (get_bty.snd) nbtys)
-
- get_bty (Banged ty) = get_ty ty
- get_bty (Unbanged ty) = get_ty ty
-
-get_ty (MonoTyVar tv)
- = emptyUniqSet
-get_ty (MonoTyApp name tys)
- = (if isTyConName name then set_name name else emptyUniqSet)
- `unionUniqSets` get_tys tys
+-- mk_cls_edges looks only at the context of class decls
+-- Its used when we are figuring out if there's a cycle in the
+-- superclass hierarchy
+
+mk_cls_edges :: RenamedHsDecl -> Maybe (RenamedHsDecl, Unique, [Unique])
+
+mk_cls_edges decl@(ClD (ClassDecl ctxt name _ _ _ _ _ _ _))
+ = Just (decl, getUnique name, map (getUnique . fst) ctxt)
+mk_cls_edges other_decl
+ = Nothing
+
+
+mk_edges :: RenamedHsDecl -> Maybe (RenamedHsDecl, Unique, [Unique])
+
+mk_edges decl@(TyD (TyData _ ctxt name _ condecls derivs _ _))
+ = Just (decl, getUnique name, uniqSetToList (get_ctxt ctxt `unionUniqSets`
+ get_cons condecls `unionUniqSets`
+ get_deriv derivs))
+
+mk_edges decl@(TyD (TySynonym name _ rhs _))
+ = Just (decl, getUnique name, uniqSetToList (get_ty rhs))
+
+mk_edges decl@(ClD (ClassDecl ctxt name _ sigs _ _ _ _ _))
+ = Just (decl, getUnique name, uniqSetToList (get_ctxt ctxt `unionUniqSets`
+ get_sigs sigs))
+
+mk_edges other_decl = Nothing
+
+get_ctxt ctxt = unionManyUniqSets (map (set_name.fst) ctxt)
+
+get_deriv Nothing = emptyUniqSet
+get_deriv (Just clss) = unionManyUniqSets (map set_name clss)
+
+get_cons cons = unionManyUniqSets (map get_con cons)
+
+get_con (ConDecl _ _ ctxt details _)
+ = get_ctxt ctxt `unionUniqSets` get_con_details details
+
+get_con_details (VanillaCon btys) = unionManyUniqSets (map get_bty btys)
+get_con_details (InfixCon bty1 bty2) = unionUniqSets (get_bty bty1) (get_bty bty2)
+get_con_details (NewCon ty) = get_ty ty
+get_con_details (RecCon nbtys) = unionManyUniqSets (map (get_bty.snd) nbtys)
+
+get_bty (Banged ty) = get_ty ty
+get_bty (Unbanged ty) = get_ty ty
+
+get_ty (MonoTyVar name)
+ = if isTvOcc (nameOccName name) then emptyUniqSet else set_name name
+get_ty (MonoTyApp ty1 ty2)
+ = unionUniqSets (get_ty ty1) (get_ty ty2)
get_ty (MonoFunTy ty1 ty2)
= unionUniqSets (get_ty ty1) (get_ty ty2)
get_ty (MonoListTy ty)
- = get_ty ty -- careful when defining [] (,,) etc as
-get_ty (MonoTupleTy tys) -- [ty] (ty,ty,ty) will not give edges!
- = get_tys tys
-get_ty other = panic "TcTyClsDecls:get_ty"
-
-get_pty (HsForAllTy _ ctxt mty)
+ = set_name listTyCon_name `unionUniqSets` get_ty ty
+get_ty (MonoTupleTy tys boxed)
+ = set_name (tupleTyCon_name boxed (length tys)) `unionUniqSets` get_tys tys
+get_ty (HsForAllTy _ ctxt mty)
= get_ctxt ctxt `unionUniqSets` get_ty mty
-get_pty other = panic "TcTyClsDecls:get_pty"
+get_ty other = panic "TcTyClsDecls:get_ty"
get_tys tys
= unionManyUniqSets (map get_ty tys)
get_sigs sigs
= unionManyUniqSets (map get_sig sigs)
where
- get_sig (ClassOpSig _ ty _ _) = get_pty ty
+ get_sig (ClassOpSig _ _ ty _) = get_ty ty
get_sig other = panic "TcTyClsDecls:get_sig"
-set_name name = singletonUniqSet (getItsUnique name)
+set_name name = unitUniqSet (getUnique name)
set_to_bag set = listToBag (uniqSetToList set)
\end{code}
+
+get_binders
+~~~~~~~~~~~
Extract *binding* names from type and class decls. Type variables are
-bound in type, data, newtype and class declarations and the polytypes
-in the class op sigs.
+bound in type, data, newtype and class declarations,
+ *and* the polytypes in the class op sigs.
+ *and* the existentially quantified contexts in datacon decls
Why do we need to grab all these type variables at once, including
those locally-quantified type variables in class op signatures?
+
+ [Incidentally, this only works because the names are all unique by now.]
+
Because we can only commit to the final kind of a type variable when
we've completed the mutually recursive group. For example:
\begin{code}
-get_binders :: Bag Decl
- -> ([Name], -- TyVars; no dups
- [Name], -- Tycons; no dups
- [Name]) -- Classes; no dups
+get_binders :: [RenamedHsDecl]
+ -> ([HsTyVar Name], -- TyVars; no dups
+ [(Name, Maybe Arity)], -- Tycons; no dups; arities for synonyms
+ [(Name, Arity)]) -- Classes; no dups; with their arities
get_binders decls = (bagToList tyvars, bagToList tycons, bagToList classes)
where
- (tyvars, tycons, classes) = foldBag union3 get_binders1
- (emptyBag,emptyBag,emptyBag)
- decls
+ (tyvars, tycons, classes) = foldr (union3 . get_binders1)
+ (emptyBag,emptyBag,emptyBag)
+ decls
union3 (a1,a2,a3) (b1,b2,b3)
= (a1 `unionBags` b1, a2 `unionBags` b2, a3 `unionBags` b3)
-get_binders1 (TyD (TyData _ name tyvars _ _ _ _))
- = (listToBag tyvars, unitBag name, emptyBag)
-get_binders1 (TyD (TyNew _ name tyvars _ _ _ _))
- = (listToBag tyvars, unitBag name, emptyBag)
get_binders1 (TyD (TySynonym name tyvars _ _))
- = (listToBag tyvars, unitBag name, emptyBag)
-get_binders1 (ClD (ClassDecl _ name tyvar sigs _ _ _))
- = (unitBag tyvar `unionBags` sigs_tvs sigs,
- emptyBag, unitBag name)
-
--- ToDo: will this duplicate the class tyvar
+ = (listToBag tyvars, unitBag (name, Just (length tyvars)), emptyBag)
+get_binders1 (TyD (TyData _ _ name tyvars condecls _ _ _))
+ = (listToBag tyvars `unionBags` cons_tvs condecls,
+ unitBag (name,Nothing), emptyBag)
+get_binders1 (ClD (ClassDecl _ name tyvars sigs _ _ _ _ _))
+ = (listToBag tyvars `unionBags` sigs_tvs sigs,
+ emptyBag, unitBag (name, length tyvars))
+
+cons_tvs condecls = unionManyBags (map con_tvs condecls)
+ where
+ con_tvs (ConDecl _ tvs _ _ _) = listToBag tvs
sigs_tvs sigs = unionManyBags (map sig_tvs sigs)
where
- sig_tvs (ClassOpSig _ ty _ _) = pty_tvs ty
- pty_tvs (HsForAllTy tvs _ _) = listToBag tvs
+ sig_tvs (ClassOpSig _ _ ty _) = pty_tvs ty
+ pty_tvs (HsForAllTy tvs _ _) = listToBag tvs -- tvs doesn't include the class tyvar
+ pty_tvs other = emptyBag
\end{code}
\begin{code}
-typeCycleErr syn_cycles sty
- = ppAboves (map (pp_cycle sty "Cycle in type declarations ...") syn_cycles)
+typeCycleErr syn_cycles
+ = vcat (map (pp_cycle "Cycle in type declarations:") syn_cycles)
-classCycleErr cls_cycles sty
- = ppAboves (map (pp_cycle sty "Cycle in class declarations ...") cls_cycles)
+classCycleErr cls_cycles
+ = vcat (map (pp_cycle "Cycle in class declarations:") cls_cycles)
-pp_cycle sty str things
- = ppHang (ppStr str)
- 4 (ppAboves (map pp_thing things))
+pp_cycle str decls
+ = hang (text str)
+ 4 (vcat (map pp_decl decls))
where
- pp_thing (pp_name, loc)
- = ppCat [pp_name, ppr sty loc]
+ pp_decl decl
+ = hsep [quotes (ppr name), ptext SLIT("at"), ppr (getSrcLoc name)]
+ where
+ name = hsDeclName decl
\end{code}
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