%
-% (c) The AQUA Project, Glasgow University, 1996
+% (c) The AQUA Project, Glasgow University, 1996-1998
%
\section[TcTyClsDecls]{Typecheck type and class declarations}
\begin{code}
module TcTyClsDecls (
- tcTyAndClassDecls1
+ tcTyAndClassDecls
) where
#include "HsVersions.h"
-import HsSyn ( HsDecl(..), TyDecl(..), ClassDecl(..),
- HsType(..), HsTyVar,
+import HsSyn ( HsDecl(..), TyClDecl(..),
+ HsType(..), HsTyVarBndr,
ConDecl(..), ConDetails(..), BangType(..),
- Sig(..),
- hsDeclName
+ Sig(..), HsPred(..), HsTupCon(..),
+ tyClDeclName, isClassDecl, isSynDecl
)
-import RnHsSyn ( RenamedTyDecl(..), RenamedClassDecl(..), RenamedHsDecl )
-import TcHsSyn ( TcHsBinds )
-import BasicTypes ( RecFlag(..) )
+import RnHsSyn ( RenamedHsDecl, RenamedTyClDecl, listTyCon_name )
+import BasicTypes ( RecFlag(..), NewOrData(..), Arity )
import TcMonad
import Inst ( InstanceMapper )
-import TcClassDcl ( tcClassDecl1 )
-import TcEnv ( TcIdOcc(..), GlobalValueEnv, tcExtendTyConEnv, tcExtendClassEnv )
-import TcKind ( TcKind, newKindVar, newKindVars, tcDefaultKind, kindToTcKind )
-import TcTyDecls ( tcTyDecl, mkDataBinds )
-import TcMonoType ( tcTyVarScope )
-
-import TyCon ( tyConKind, tyConArity, isSynTyCon )
-import Class ( Class, classBigSig )
-import TyVar ( tyVarKind )
+import TcClassDcl ( kcClassDecl, tcClassDecl1 )
+import TcEnv ( ValueEnv, TcTyThing(..),
+ tcExtendTypeEnv, getEnvAllTyCons
+ )
+import TcTyDecls ( tcTyDecl, kcTyDecl )
+import TcMonoType ( kcHsTyVar )
+import TcType ( TcKind, newKindVar, newKindVars, kindToTcKind, zonkTcKindToKind )
+
+import Type ( mkArrowKind, boxedTypeKind )
+
+import Class ( Class )
+import Var ( TyVar, tyVarKind )
+import FiniteMap
import Bag
+import VarSet
import Digraph ( stronglyConnComp, SCC(..) )
import Name ( Name, NamedThing(..), getSrcLoc, isTvOcc, nameOccName )
import Outputable
-import Maybes ( mapMaybe )
+import Maybes ( mapMaybe, catMaybes, expectJust )
import UniqSet ( UniqSet, emptyUniqSet,
unitUniqSet, unionUniqSets,
unionManyUniqSets, uniqSetToList )
+import ErrUtils ( Message )
import SrcLoc ( SrcLoc )
-import TyCon ( TyCon, Arity )
+import TyCon ( TyCon, ArgVrcs )
+import Variance ( calcTyConArgVrcs )
import Unique ( Unique, Uniquable(..) )
-import Util ( panic{-, pprTrace-} )
-
+import UniqFM ( listToUFM, lookupUFM )
\end{code}
The main function
~~~~~~~~~~~~~~~~~
\begin{code}
-tcTyAndClassDecls1 :: GlobalValueEnv -> InstanceMapper -- Knot tying stuff
- -> [RenamedHsDecl]
- -> TcM s (TcEnv s)
+tcTyAndClassDecls :: ValueEnv -> InstanceMapper -- Knot tying stuff
+ -> [RenamedHsDecl]
+ -> TcM s TcEnv
-tcTyAndClassDecls1 unf_env inst_mapper decls
+tcTyAndClassDecls unf_env inst_mapper decls
= sortByDependency decls `thenTc` \ groups ->
tcGroups unf_env inst_mapper groups
returnTc 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
- 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
+ = tcGroup unf_env inst_mapper group `thenTc` \ env ->
+ tcSetEnv env $
tcGroups unf_env inst_mapper groups
- where
- classKind clas = map (kindToTcKind . tyVarKind) tyvars
- where
- (tyvars, _, _, _, _) = classBigSig clas
\end{code}
Dealing with a group
~~~~~~~~~~~~~~~~~~~~
-Notice the uses of @zipLazy@, which makes sure
-that the knot-tied TyVars, TyCons and Classes aren't looked at too early.
+The knot-tying parameters: @rec_tyclss@ is an alist mapping @Name@s to
+@TcTyThing@s. @rec_vrcs@ is a finite map from @Name@s to @ArgVrcs@s.
-
\begin{code}
-tcGroup :: GlobalValueEnv -> InstanceMapper -> SCC RenamedHsDecl -> TcM s ([TyCon], [Class])
+tcGroup :: ValueEnv -> InstanceMapper -> SCC RenamedTyClDecl -> TcM s TcEnv
tcGroup unf_env inst_mapper scc
- = -- TIE THE KNOT
- fixTc ( \ ~(rec_tycons, rec_classes) ->
-
- -- EXTEND TYPE AND CLASS ENVIRONMENTS
- let
- mk_tycon_bind (name, arity) = newKindVar `thenNF_Tc` \ kind ->
- returnNF_Tc (name, (kind, arity, find name rec_tycons))
-
- mk_class_bind (name, arity) = newKindVars arity `thenNF_Tc` \ kinds ->
- returnNF_Tc (name, (kinds, find name rec_classes))
-
- find name [] = pprPanic "tcGroup" (ppr name)
- find name (thing:things) | name == getName thing = thing
- | otherwise = find name things
-
- 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
- foldlTc (tcDecl is_rec_group unf_env inst_mapper) ([], []) decls
- ) `thenTc` \ (tycons, classes) ->
-
- returnTc (tycons, classes)
- )
+ = -- Do kind checking
+ mapNF_Tc getTyBinding1 decls `thenNF_Tc` \ ty_env_stuff1 ->
+ tcExtendTypeEnv ty_env_stuff1 (mapTc kcDecl decls) `thenTc_`
+
+ -- Tie the knot
+-- traceTc (ppr (map fst ty_env_stuff1)) `thenTc_`
+ fixTc ( \ ~(rec_tyclss, _) ->
+ let
+ rec_env = listToUFM rec_tyclss
+ rec_tycons = getEnvAllTyCons rec_tyclss
+ rec_vrcs = calcTyConArgVrcs rec_tycons
+ in
+
+ -- Do type checking
+ mapNF_Tc (getTyBinding2 rec_env) ty_env_stuff1 `thenNF_Tc` \ ty_env_stuff2 ->
+ tcExtendTypeEnv ty_env_stuff2 $
+ mapTc (tcDecl is_rec_group unf_env inst_mapper rec_vrcs) decls
+ `thenTc` \ tyclss ->
+
+ tcGetEnv `thenTc` \ env ->
+ returnTc (tyclss, env)
+ ) `thenTc` \ (_, env) ->
+-- traceTc (text "done" <+> ppr (map fst ty_env_stuff1)) `thenTc_`
+ returnTc env
where
is_rec_group = case scc of
AcyclicSCC _ -> NonRecursive
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}
+kcDecl decl
+ = tcAddDeclCtxt decl $
+ if isClassDecl decl then
+ kcClassDecl decl
+ else
+ kcTyDecl decl
+
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)
+ -> ValueEnv -> InstanceMapper -> FiniteMap Name ArgVrcs
+ -> RenamedTyClDecl -> TcM s (Name, TcTyThing)
+
+tcDecl is_rec_group unf_env inst_mapper vrcs_env decl
+ = tcAddDeclCtxt decl $
+ if isClassDecl decl then
+ tcClassDecl1 unf_env inst_mapper vrcs_env decl
+ else
+ tcTyDecl is_rec_group vrcs_env decl
+
+
+tcAddDeclCtxt decl thing_inside
+ = tcAddSrcLoc loc $
+ tcAddErrCtxt ctxt $
+ thing_inside
+ where
+ (name, loc, thing)
+ = case decl of
+ (ClassDecl _ name _ _ _ _ _ _ _ _ _ loc) -> (name, loc, "class")
+ (TySynonym name _ _ loc) -> (name, loc, "type synonym")
+ (TyData NewType _ name _ _ _ _ _ loc) -> (name, loc, "data type")
+ (TyData DataType _ name _ _ _ _ _ loc) -> (name, loc, "newtype")
+
+ ctxt = hsep [ptext SLIT("In the"), text thing,
+ ptext SLIT("declaration for"), quotes (ppr name)]
+\end{code}
+
+
+getTyBinders
+~~~~~~~~~~~
+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.
+ *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:
+
+class C a where
+ op :: D b => a -> b -> b
+
+class D c where
+ bop :: (Monad c) => ...
+
+Here, the kind of the locally-polymorphic type variable "b"
+depends on *all the uses of class D*. For example, the use of
+Monad c in bop's type signature means that D must have kind Type->Type.
+
+ [April 00: looks as if we've dropped this subtlety; I'm not sure when]
+
+\begin{code}
+getTyBinding1 :: RenamedTyClDecl -> NF_TcM s (Name, (TcKind, TcTyThing))
+getTyBinding1 (TySynonym name tyvars _ _)
+ = mapNF_Tc kcHsTyVar tyvars `thenNF_Tc` \ arg_kinds ->
+ newKindVar `thenNF_Tc` \ result_kind ->
+ returnNF_Tc (name, (foldr mkArrowKind result_kind arg_kinds,
+ ASynTyCon (pprPanic "ATyCon: syn" (ppr name)) (length tyvars)))
+
+getTyBinding1 (TyData _ _ name tyvars _ _ _ _ _)
+ = mapNF_Tc kcHsTyVar tyvars `thenNF_Tc` \ arg_kinds ->
+ returnNF_Tc (name, (foldr mkArrowKind boxedTypeKind arg_kinds,
+ ADataTyCon (error "ATyCon: data")))
+
+getTyBinding1 (ClassDecl _ name tyvars _ _ _ _ _ _ _ _ _)
+ = mapNF_Tc kcHsTyVar tyvars `thenNF_Tc` \ arg_kinds ->
+ returnNF_Tc (name, (foldr mkArrowKind boxedTypeKind arg_kinds,
+ AClass (pprPanic "AClass" (ppr name)) (length tyvars)))
+
+-- Zonk the kind to its final form, and lookup the
+-- recursive tycon/class
+getTyBinding2 rec_env (name, (tc_kind, thing))
+ = zonkTcKindToKind tc_kind `thenNF_Tc` \ kind ->
+ returnNF_Tc (name, (kind, mk_thing thing (lookupUFM rec_env name)))
+ where
+ mk_thing (ADataTyCon _) ~(Just (ADataTyCon tc)) = ADataTyCon tc
+ mk_thing (ASynTyCon _ arity) ~(Just (ASynTyCon tc _)) = ASynTyCon tc arity
+ mk_thing (AClass _ arity) ~(Just (AClass cls _)) = AClass cls arity
\end{code}
+
+%************************************************************************
+%* *
+\subsection{Dependency analysis}
+%* *
+%************************************************************************
+
Dependency analysis
~~~~~~~~~~~~~~~~~~~
\begin{code}
-sortByDependency :: [RenamedHsDecl] -> TcM s [SCC RenamedHsDecl]
+sortByDependency :: [RenamedHsDecl] -> TcM s [SCC RenamedTyClDecl]
sortByDependency decls
- = let -- CHECK FOR SYNONYM CYCLES
+ = let -- CHECK FOR CLASS CYCLES
+ cls_sccs = stronglyConnComp (mapMaybe mk_cls_edges tycl_decls)
+ cls_cycles = [ decls | CyclicSCC decls <- cls_sccs]
+ in
+ checkTc (null cls_cycles) (classCycleErr cls_cycles) `thenTc_`
+
+ let -- CHECK FOR SYNONYM CYCLES
syn_sccs = stronglyConnComp (filter is_syn_decl edges)
syn_cycles = [ decls | CyclicSCC decls <- syn_sccs]
in
checkTc (null syn_cycles) (typeCycleErr syn_cycles) `thenTc_`
- let -- CHECK FOR CLASS CYCLES
- cls_sccs = stronglyConnComp (filter is_cls_decl edges)
- cls_cycles = [ decls | CyclicSCC decls <- cls_sccs]
-
- in
- checkTc (null cls_cycles) (classCycleErr cls_cycles) `thenTc_`
-
- -- DO THE MAIN DEPENDENCY ANALYSIS
+ -- DO THE MAIN DEPENDENCY ANALYSIS
let
- decl_sccs = stronglyConnComp (filter is_ty_cls_decl edges)
+ decl_sccs = stronglyConnComp edges
in
returnTc decl_sccs
-
where
- edges = mapMaybe mk_edges decls
+ tycl_decls = [d | TyClD d <- decls]
+ edges = map mk_edges tycl_decls
-bag_acyclic (AcyclicSCC scc) = unitBag scc
-bag_acyclic (CyclicSCC sccs) = listToBag sccs
-
-is_syn_decl (TyD (TySynonym _ _ _ _), _, _) = True
-is_syn_decl _ = False
-
-is_ty_cls_decl (TyD _, _, _) = True
-is_ty_cls_decl (ClD _, _, _) = True
-is_ty_cls_decl other = False
-
-is_cls_decl (ClD _, _, _) = True
-is_cls_decl other = False
+ is_syn_decl (d, _, _) = isSynDecl d
\end{code}
Edges in Type/Class decls
~~~~~~~~~~~~~~~~~~~~~~~~~
+
\begin{code}
-mk_edges decl@(TyD (TyData _ ctxt name _ condecls derivs _ _))
- = Just (decl, uniqueOf name, uniqSetToList (get_ctxt ctxt `unionUniqSets`
- get_cons condecls `unionUniqSets`
+----------------------------------------------------
+-- 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 :: RenamedTyClDecl -> Maybe (RenamedTyClDecl, Unique, [Unique])
+
+mk_cls_edges decl@(ClassDecl ctxt name _ _ _ _ _ _ _ _ _ _)
+ = Just (decl, getUnique name, map getUnique (catMaybes (map get_clas ctxt)))
+mk_cls_edges other_decl
+ = Nothing
+
+----------------------------------------------------
+mk_edges :: RenamedTyClDecl -> (RenamedTyClDecl, Unique, [Unique])
+
+mk_edges decl@(TyData _ ctxt name _ condecls _ derivs _ _)
+ = (decl, getUnique name, uniqSetToList (get_ctxt ctxt `unionUniqSets`
+ get_cons condecls `unionUniqSets`
get_deriv derivs))
-mk_edges decl@(TyD (TySynonym name _ rhs _))
- = Just (decl, uniqueOf name, uniqSetToList (get_ty rhs))
+mk_edges decl@(TySynonym name _ rhs _)
+ = (decl, getUnique name, uniqSetToList (get_ty rhs))
-mk_edges decl@(ClD (ClassDecl ctxt name _ sigs _ _ _ _ _))
- = Just (decl, uniqueOf name, uniqSetToList (get_ctxt ctxt `unionUniqSets`
+mk_edges decl@(ClassDecl ctxt name _ _ sigs _ _ _ _ _ _ _)
+ = (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_ctxt ctxt = unionManyUniqSets (map set_name (catMaybes (map get_clas ctxt)))
+get_clas (HsPClass clas _) = Just clas
+get_clas _ = Nothing
+----------------------------------------------------
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_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 (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 tc ty)
- = set_name tc `unionUniqSets` get_ty ty
-get_ty (MonoTupleTy tc tys)
- = set_name tc `unionUniqSets` get_tys tys
-get_ty (HsForAllTy _ ctxt mty)
- = get_ctxt ctxt `unionUniqSets` get_ty mty
-get_ty other = panic "TcTyClsDecls:get_ty"
-
-get_tys tys
- = unionManyUniqSets (map get_ty tys)
-
+get_bty (Unpacked ty) = get_ty ty
+
+----------------------------------------------------
+get_ty (HsTyVar name) | isTvOcc (nameOccName name) = emptyUniqSet
+ | otherwise = set_name name
+get_ty (HsAppTy ty1 ty2) = unionUniqSets (get_ty ty1) (get_ty ty2)
+get_ty (HsFunTy ty1 ty2) = unionUniqSets (get_ty ty1) (get_ty ty2)
+get_ty (HsListTy ty) = set_name listTyCon_name `unionUniqSets` get_ty ty
+get_ty (HsTupleTy (HsTupCon n _) tys) = set_name n `unionUniqSets` get_tys tys
+get_ty (HsUsgTy _ ty) = get_ty ty
+get_ty (HsUsgForAllTy _ ty) = get_ty ty
+get_ty (HsForAllTy _ ctxt mty) = get_ctxt ctxt `unionUniqSets` get_ty mty
+get_ty (HsPredTy (HsPClass name _)) = set_name name
+get_ty (HsPredTy (HsPIParam _ _)) = emptyUniqSet -- I think
+
+----------------------------------------------------
+get_tys tys = unionManyUniqSets (map get_ty tys)
+
+----------------------------------------------------
get_sigs sigs
= unionManyUniqSets (map get_sig sigs)
where
- get_sig (ClassOpSig _ _ ty _) = get_ty ty
+ get_sig (ClassOpSig _ _ _ ty _) = get_ty ty
+ get_sig (FixSig _) = emptyUniqSet
get_sig other = panic "TcTyClsDecls:get_sig"
-set_name name = unitUniqSet (uniqueOf 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.
-
-Why do we need to grab all these type variables at once, including
-those locally-quantified type variables in class op signatures?
-Because we can only commit to the final kind of a type variable when
-we've completed the mutually recursive group. For example:
-
-class C a where
- op :: D b => a -> b -> b
-
-class D c where
- bop :: (Monad c) => ...
-
-Here, the kind of the locally-polymorphic type variable "b"
-depends on *all the uses of class D*. For example, the use of
-Monad c in bop's type signature means that D must have kind Type->Type.
-
-
\begin{code}
-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
+typeCycleErr, classCycleErr :: [[RenamedTyClDecl]] -> Message
-get_binders decls = (bagToList tyvars, bagToList tycons, bagToList classes)
- where
- (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,Nothing), emptyBag)
-get_binders1 (TyD (TySynonym name tyvars _ _))
- = (listToBag tyvars, unitBag (name, Just (length tyvars)), emptyBag)
-get_binders1 (ClD (ClassDecl _ name tyvars sigs _ _ _ _ _))
- = (listToBag tyvars `unionBags` sigs_tvs sigs,
- emptyBag, unitBag (name, length tyvars))
-
-sigs_tvs sigs = unionManyBags (map sig_tvs sigs)
- where
- 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
= vcat (map (pp_cycle "Cycle in type declarations:") syn_cycles)
pp_decl decl
= hsep [quotes (ppr name), ptext SLIT("at"), ppr (getSrcLoc name)]
where
- name = hsDeclName decl
+ name = tyClDeclName decl
\end{code}
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