HsType(..), HsTyVarBndr,
ConDecl(..), ConDetails(..), BangType(..),
Sig(..), HsPred(..), HsTupCon(..),
- tyClDeclName, isClassDecl, isSynDecl
+ tyClDeclName, hsTyVarNames, isClassDecl, isSynDecl, isClassOpSig, getBangType
)
import RnHsSyn ( RenamedHsDecl, RenamedTyClDecl, listTyCon_name )
import BasicTypes ( RecFlag(..), NewOrData(..), Arity )
import TcMonad
-import TcClassDcl ( kcClassDecl, tcClassDecl1 )
-import TcEnv ( ValueEnv, TcTyThing(..),
- tcExtendTypeEnv, getEnvAllTyCons
+import TcEnv ( ValueEnv, TyThing(..), TyThingDetails(..), tyThingKind,
+ tcExtendTypeEnv, tcExtendKindEnv, tcLookupTy
)
-import TcTyDecls ( tcTyDecl, kcTyDecl )
-import TcMonoType ( kcHsTyVar )
-import TcType ( TcKind, newKindVar, newKindVars, kindToTcKind, zonkTcKindToKind )
-
-import Type ( mkArrowKind, boxedTypeKind )
+import TcTyDecls ( tcTyDecl1, kcConDetails, mkNewTyConRep )
+import TcClassDcl ( tcClassDecl1 )
+import TcMonoType ( kcHsTyVars, kcHsType, kcHsBoxedSigType, kcHsContext, mkTyClTyVars )
+import TcType ( TcKind, newKindVar, newKindVars, zonkKindEnv )
+import TcUnify ( unifyKind )
+import Type ( Kind, mkArrowKind, boxedTypeKind, zipFunTys )
+import Variance ( calcTyConArgVrcs )
+import Class ( Class, mkClass, classTyCon )
+import TyCon ( TyCon, ArgVrcs, AlgTyConFlavour(..), mkSynTyCon, mkAlgTyCon, mkClassTyCon )
+import DataCon ( isNullaryDataCon )
+import Var ( TyVar, tyVarKind, varName )
+import VarEnv
import FiniteMap
import Bag
import Digraph ( stronglyConnComp, SCC(..) )
-import Name ( Name, NamedThing(..), getSrcLoc, isTvOcc, nameOccName )
+import Name ( Name, NamedThing(..), NameEnv, getSrcLoc, isTvOcc, nameOccName,
+ mkNameEnv, lookupNameEnv_NF
+ )
import Outputable
-import Maybes ( mapMaybe, catMaybes, expectJust )
+import Maybes ( mapMaybe, catMaybes )
import UniqSet ( UniqSet, emptyUniqSet,
unitUniqSet, unionUniqSets,
unionManyUniqSets, uniqSetToList )
import ErrUtils ( Message )
-import TyCon ( TyCon, ArgVrcs )
-import Variance ( calcTyConArgVrcs )
import Unique ( Unique, Uniquable(..) )
-import UniqFM ( listToUFM, lookupUFM )
\end{code}
+
+%************************************************************************
+%* *
+\subsection{Type checking for type and class declarations}
+%* *
+%************************************************************************
+
The main function
~~~~~~~~~~~~~~~~~
\begin{code}
Dealing with a group
~~~~~~~~~~~~~~~~~~~~
-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.
+Consider a mutually-recursive group, binding
+a type constructor T and a class C.
+
+Step 1: getInitialKind
+ Construct a KindEnv by binding T and C to a kind variable
+
+Step 2: kcTyClDecl
+ In that environment, do a kind check
+
+Step 3: Zonk the kinds
+
+Step 4: buildTyConOrClass
+ Construct an environment binding T to a TyCon and C to a Class.
+ a) Their kinds comes from zonking the relevant kind variable
+ b) Their arity (for synonyms) comes direct from the decl
+ c) The funcional dependencies come from the decl
+ d) The rest comes a knot-tied binding of T and C, returned from Step 4
+ e) The variances of the tycons in the group is calculated from
+ the knot-tied stuff
+
+Step 5: tcTyClDecl1
+ In this environment, walk over the decls, constructing the TyCons and Classes.
+ This uses in a strict way items (a)-(c) above, which is why they must
+ be constructed in Step 4.
+ Feed the results back to Step 4.
+
+The knot-tying parameters: @rec_details_list@ is an alist mapping @Name@s to
+@TyThing@s. @rec_vrcs@ is a finite map from @Name@s to @ArgVrcs@s.
\begin{code}
tcGroup :: ValueEnv -> SCC RenamedTyClDecl -> TcM s TcEnv
tcGroup unf_env scc
- = -- Do kind checking
- mapNF_Tc getTyBinding1 decls `thenNF_Tc` \ ty_env_stuff1 ->
- tcExtendTypeEnv ty_env_stuff1 (mapTc kcDecl decls) `thenTc_`
+ = -- Step 1
+ mapNF_Tc getInitialKind decls `thenNF_Tc` \ initial_kinds ->
+
+ -- Step 2
+ tcExtendKindEnv initial_kinds (mapTc kcTyClDecl decls) `thenTc_`
+
+ -- Step 3
+ zonkKindEnv initial_kinds `thenNF_Tc` \ final_kinds ->
-- 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
+ fixTc ( \ ~(rec_details_list, _) ->
+ -- Step 4
+ let
+ kind_env = mkNameEnv final_kinds
+ rec_details = mkNameEnv rec_details_list
+
+ tyclss, all_tyclss :: [(Name, TyThing)]
+ tyclss = map (buildTyConOrClass is_rec kind_env rec_vrcs rec_details) decls
+
+ -- Add the tycons that come from the classes
+ -- We want them in the environment because
+ -- they are mentioned in interface files
+ all_tyclss = [ (getName tycon, ATyCon tycon) | (_, AClass clas) <- tyclss,
+ let tycon = classTyCon clas
+ ] ++ tyclss
+
+ -- Calculate variances, and (yes!) feed back into buildTyConOrClass.
+ rec_vrcs = calcTyConArgVrcs [tc | (_, ATyCon tc) <- all_tyclss]
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 rec_vrcs) decls `thenTc` \ tyclss ->
-
- tcGetEnv `thenTc` \ env ->
- returnTc (tyclss, env)
+ -- Step 5
+ tcExtendTypeEnv all_tyclss $
+ mapTc (tcTyClDecl1 unf_env) decls `thenTc` \ tycls_details ->
+ tcGetEnv `thenNF_Tc` \ env ->
+ returnTc (tycls_details, env)
) `thenTc` \ (_, env) ->
--- traceTc (text "done" <+> ppr (map fst ty_env_stuff1)) `thenTc_`
returnTc env
where
- is_rec_group = case scc of
- AcyclicSCC _ -> NonRecursive
- CyclicSCC _ -> Recursive
+ is_rec = case scc of
+ AcyclicSCC _ -> NonRecursive
+ CyclicSCC _ -> Recursive
decls = case scc of
AcyclicSCC decl -> [decl]
CyclicSCC decls -> decls
+
+tcTyClDecl1 :: ValueEnv -> RenamedTyClDecl -> TcM s (Name, TyThingDetails)
+
+tcTyClDecl1 unf_env decl
+ | isClassDecl decl = tcClassDecl1 unf_env decl
+ | otherwise = tcTyDecl1 decl
\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
- -> ValueEnv -> FiniteMap Name ArgVrcs
- -> RenamedTyClDecl -> TcM s (Name, TcTyThing)
-
-tcDecl is_rec_group unf_env vrcs_env decl
- = tcAddDeclCtxt decl $
- if isClassDecl decl then
- tcClassDecl1 unf_env 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")
+%************************************************************************
+%* *
+\subsection{Step 1: Initial environment}
+%* *
+%************************************************************************
- ctxt = hsep [ptext SLIT("In the"), text thing,
- ptext SLIT("declaration for"), quotes (ppr name)]
-\end{code}
+\begin{code}
+getInitialKind :: RenamedTyClDecl -> NF_TcM s (Name, TcKind)
+getInitialKind (TySynonym name tyvars _ _)
+ = kcHsTyVars tyvars `thenNF_Tc` \ arg_kinds ->
+ newKindVar `thenNF_Tc` \ result_kind ->
+ returnNF_Tc (name, mk_kind arg_kinds result_kind)
+getInitialKind (TyData _ _ name tyvars _ _ _ _ _)
+ = kcHsTyVars tyvars `thenNF_Tc` \ arg_kinds ->
+ returnNF_Tc (name, mk_kind arg_kinds boxedTypeKind)
-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
+getInitialKind (ClassDecl _ name tyvars _ _ _ _ _ _ _ _ _)
+ = kcHsTyVars tyvars `thenNF_Tc` \ arg_kinds ->
+ returnNF_Tc (name, mk_kind arg_kinds boxedTypeKind)
+
+mk_kind tvs_w_kinds res_kind = foldr (mkArrowKind . snd) res_kind tvs_w_kinds
+\end{code}
-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.]
+%************************************************************************
+%* *
+\subsection{Step 2: Kind checking}
+%* *
+%************************************************************************
-Because we can only commit to the final kind of a type variable when
-we've completed the mutually recursive group. For example:
+We need to kind check all types in the mutually recursive group
+before we know the kind of the type variables. For example:
class C a where
op :: D b => a -> b -> 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}
+kcTyClDecl :: RenamedTyClDecl -> TcM s ()
+
+kcTyClDecl decl@(TySynonym tycon_name hs_tyvars rhs loc)
+ = tcAddDeclCtxt decl $
+ kcTyClDeclBody tycon_name hs_tyvars $ \ result_kind ->
+ kcHsType rhs `thenTc` \ rhs_kind ->
+ unifyKind result_kind rhs_kind
+
+kcTyClDecl decl@(TyData _ context tycon_name hs_tyvars con_decls _ _ _ loc)
+ = tcAddDeclCtxt decl $
+ kcTyClDeclBody tycon_name hs_tyvars $ \ result_kind ->
+ kcHsContext context `thenTc_`
+ mapTc_ kc_con_decl con_decls
+ where
+ kc_con_decl (ConDecl _ _ ex_tvs ex_ctxt details loc)
+ = tcAddSrcLoc loc $
+ kcHsTyVars ex_tvs `thenNF_Tc` \ kind_env ->
+ tcExtendKindEnv kind_env $
+ kcConDetails ex_ctxt details
+
+kcTyClDecl decl@(ClassDecl context class_name
+ hs_tyvars fundeps class_sigs
+ _ _ _ _ _ _ loc)
+ = tcAddDeclCtxt decl $
+ kcTyClDeclBody class_name hs_tyvars $ \ result_kind ->
+ kcHsContext context `thenTc_`
+ mapTc_ kc_sig (filter isClassOpSig class_sigs)
+ where
+ kc_sig (ClassOpSig _ _ _ op_ty loc) = tcAddSrcLoc loc (kcHsBoxedSigType op_ty)
+
+kcTyClDeclBody :: Name -> [HsTyVarBndr Name] -- Kind of the tycon/cls and its tyvars
+ -> (Kind -> TcM s a) -- Thing inside
+ -> TcM s a
+-- Extend the env with bindings for the tyvars, taken from
+-- the kind of the tycon/class. Give it to the thing inside, and
+-- check the result kind matches
+kcTyClDeclBody tc_name hs_tyvars thing_inside
+ = tcLookupTy tc_name `thenNF_Tc` \ tc ->
+ let
+ (tyvars_w_kinds, result_kind) = zipFunTys (hsTyVarNames hs_tyvars) (tyThingKind tc)
+ in
+ tcExtendKindEnv tyvars_w_kinds (thing_inside result_kind)
+\end{code}
+
+
+%************************************************************************
+%* *
+\subsection{Step 4: Building the tycon/class}
+%* *
+%************************************************************************
\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)))
+buildTyConOrClass
+ :: RecFlag -> NameEnv Kind
+ -> FiniteMap TyCon ArgVrcs -> NameEnv TyThingDetails
+ -> RenamedTyClDecl -> (Name, TyThing)
+ -- Can't fail; the only reason it's in the monad
+ -- is so it can zonk the kinds
+
+buildTyConOrClass is_rec kenv rec_vrcs rec_details
+ (TySynonym tycon_name tyvar_names rhs src_loc)
+ = (tycon_name, ATyCon tycon)
+ where
+ tycon = mkSynTyCon tycon_name tycon_kind arity tyvars rhs_ty argvrcs
+ tycon_kind = lookupNameEnv_NF kenv tycon_name
+ arity = length tyvar_names
+ tyvars = mkTyClTyVars tycon_kind tyvar_names
+ SynTyDetails rhs_ty = lookupNameEnv_NF rec_details tycon_name
+ argvrcs = lookupWithDefaultFM rec_vrcs bogusVrcs tycon
+
+buildTyConOrClass is_rec kenv rec_vrcs rec_details
+ (TyData data_or_new context tycon_name tyvar_names _ nconstrs _ _ src_loc)
+ = (tycon_name, ATyCon tycon)
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
+ tycon = mkAlgTyCon tycon_name tycon_kind tyvars ctxt argvrcs
+ data_cons nconstrs
+ derived_classes
+ flavour is_rec
+
+ DataTyDetails ctxt data_cons derived_classes = lookupNameEnv_NF rec_details tycon_name
+
+ tycon_kind = lookupNameEnv_NF kenv tycon_name
+ tyvars = mkTyClTyVars tycon_kind tyvar_names
+ argvrcs = lookupWithDefaultFM rec_vrcs bogusVrcs tycon
+
+ flavour = case data_or_new of
+ NewType -> NewTyCon (mkNewTyConRep tycon)
+ DataType | all isNullaryDataCon data_cons -> EnumTyCon
+ | otherwise -> DataTyCon
+
+buildTyConOrClass is_rec kenv rec_vrcs rec_details
+ (ClassDecl context class_name
+ tyvar_names fundeps class_sigs def_methods pragmas
+ tycon_name datacon_name datacon_wkr_name sc_sel_names src_loc)
+ = (class_name, AClass clas)
+ where
+ clas = mkClass class_name tyvars fds
+ sc_theta sc_sel_ids op_items
+ tycon
+
+ tycon = mkClassTyCon tycon_name class_kind tyvars
+ argvrcs dict_con
+ clas -- Yes! It's a dictionary
+ flavour
+
+ ClassDetails sc_theta sc_sel_ids op_items dict_con = lookupNameEnv_NF rec_details class_name
+
+ class_kind = lookupNameEnv_NF kenv class_name
+ tyvars = mkTyClTyVars class_kind tyvar_names
+ argvrcs = lookupWithDefaultFM rec_vrcs bogusVrcs tycon
+ n_fields = length sc_sel_ids + length op_items
+
+ flavour | n_fields == 1 = NewTyCon (mkNewTyConRep tycon)
+ | otherwise = DataTyCon
+
+ -- We can find the functional dependencies right away,
+ -- and it is vital to do so. Why? Because in the next pass
+ -- we check for ambiguity in all the type signatures, and we
+ -- need the functional dependcies to be done by then
+ fds = [(map lookup xs, map lookup ys) | (xs,ys) <- fundeps]
+ tyvar_env = mkNameEnv [(varName tv, tv) | tv <- tyvars]
+ lookup = lookupNameEnv_NF tyvar_env
+
+bogusVrcs = panic "Bogus tycon arg variances"
\end{code}
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_bty (Unpacked ty) = get_ty ty
+get_bty bty = get_ty (getBangType bty)
----------------------------------------------------
get_ty (HsTyVar name) | isTvOcc (nameOccName name) = emptyUniqSet
\end{code}
+%************************************************************************
+%* *
+\subsection{Error management
+%* *
+%************************************************************************
+
+\begin{code}
+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}
+
\begin{code}
typeCycleErr, classCycleErr :: [[RenamedTyClDecl]] -> Message
projects / ghc-hetmet.git / blobdiff