X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Fcompiler%2Ftypecheck%2FTcTyDecls.lhs;h=450dad952c46465bb45262a215f73b95473a6614;hb=27c253536ba2eeae99e6b5e07a9c5ec7bd2f063b;hp=73916b6f45eccc0f37715cdb4b44a3a07b7cfdb2;hpb=2f51f1402e6869c0f049ffbe7b019bf6ab80558f;p=ghc-hetmet.git diff --git a/ghc/compiler/typecheck/TcTyDecls.lhs b/ghc/compiler/typecheck/TcTyDecls.lhs index 73916b6..450dad9 100644 --- a/ghc/compiler/typecheck/TcTyDecls.lhs +++ b/ghc/compiler/typecheck/TcTyDecls.lhs @@ -1,441 +1,357 @@ % -% (c) The AQUA Project, Glasgow University, 1996 +% (c) The AQUA Project, Glasgow University, 1996-1998 % \section[TcTyDecls]{Typecheck type declarations} \begin{code} -#include "HsVersions.h" - module TcTyDecls ( - tcTyDecl, + tcTyDecl, kcTyDecl, tcConDecl, - mkDataBinds + mkImplicitDataBinds, mkNewTyConRep ) where -import Ubiq{-uitous-} +#include "HsVersions.h" -import HsSyn ( TyDecl(..), ConDecl(..), BangType(..), HsExpr(..), - Match(..), GRHSsAndBinds(..), GRHS(..), OutPat(..), - HsBinds(..), HsLit, Stmt, Qual, ArithSeqInfo, - PolyType, Fake, InPat, - Bind(..), MonoBinds(..), Sig, - MonoType ) -import RnHsSyn ( RenamedTyDecl(..), RenamedConDecl(..), - RnName{-instance Outputable-} - ) -import TcHsSyn ( mkHsTyLam, mkHsDictLam, tcIdType, zonkId, - TcHsBinds(..), TcIdOcc(..) +import HsSyn ( MonoBinds(..), + TyClDecl(..), ConDecl(..), ConDetails(..), BangType(..), + andMonoBindList ) -import Inst ( newDicts, InstOrigin(..), Inst ) -import TcMonoType ( tcMonoTypeKind, tcMonoType, tcContext ) -import TcType ( tcInstTyVars, tcInstType, tcInstId ) -import TcEnv ( tcLookupTyCon, tcLookupTyVar, tcLookupClass, - newLocalId, newLocalIds +import RnHsSyn ( RenamedTyClDecl, RenamedConDecl ) +import TcHsSyn ( TcMonoBinds, idsToMonoBinds ) +import BasicTypes ( RecFlag(..), NewOrData(..) ) + +import TcMonoType ( tcExtendTopTyVarScope, tcExtendTyVarScope, + tcHsTypeKind, kcHsType, tcHsTopType, tcHsTopBoxedType, + tcContext, tcHsTopTypeKind ) +import TcType ( zonkTcTyVarToTyVar, zonkTcClassConstraints ) +import TcEnv ( tcLookupTy, TcTyThing(..) ) import TcMonad -import TcKind ( TcKind, unifyKind, mkTcArrowKind, mkTcTypeKind ) +import TcUnify ( unifyKind ) -import Class ( GenClass{-instance Eq-} ) -import Id ( mkDataCon, dataConSig, mkRecordSelId, - dataConFieldLabels, dataConStrictMarks, - StrictnessMark(..), - GenId{-instance NamedThing-} +import Class ( Class ) +import DataCon ( DataCon, mkDataCon, isNullaryDataCon, + dataConFieldLabels, dataConId, dataConWrapId, + markedStrict, notMarkedStrict, markedUnboxed, dataConRepType ) +import MkId ( mkDataConId, mkDataConWrapId, mkRecordSelId ) import FieldLabel -import Kind ( Kind, mkArrowKind, mkBoxedTypeKind ) -import SpecEnv ( SpecEnv(..), nullSpecEnv ) -import Name ( nameSrcLoc, isLocallyDefinedName, getSrcLoc, - Name{-instance Ord3-} +import Var ( Id, TyVar ) +import Name ( Name, isLocallyDefined, OccName, NamedThing(..), nameUnique ) +import Outputable +import TyCon ( TyCon, AlgTyConFlavour(..), ArgVrcs, mkSynTyCon, mkAlgTyCon, + tyConDataCons, tyConTyVars, + isSynTyCon, isNewTyCon ) -import Pretty -import TyCon ( TyCon, NewOrData(..), mkSynTyCon, mkDataTyCon, isDataTyCon, - tyConDataCons ) -import Type ( typeKind, getTyVar, tyVarsOfTypes, eqTy, - applyTyCon, mkTyVarTys, mkForAllTys, mkFunTy, - splitFunTy, mkTyVarTy, getTyVar_maybe +import Type ( getTyVar, tyVarsOfTypes, splitFunTy, applyTys, + mkTyConApp, mkTyVarTys, mkForAllTys, mkFunTy, + mkTyVarTy, splitAlgTyConApp_maybe, + mkArrowKind, mkArrowKinds, boxedTypeKind, + isUnboxedType, Type, ThetaType, classesOfPreds ) -import TyVar ( tyVarKind, elementOfTyVarSet, GenTyVar{-instance Eq-} ) -import Unique ( Unique {- instance Eq -}, evalClassKey ) -import UniqSet ( emptyUniqSet, mkUniqSet, uniqSetToList, unionManyUniqSets, UniqSet(..) ) -import Util ( equivClasses, zipEqual, panic, assertPanic ) +import TysWiredIn ( unitTy ) +import Var ( tyVarKind ) +import VarSet ( intersectVarSet, isEmptyVarSet ) +import Util ( equivClasses ) +import FiniteMap ( FiniteMap, lookupWithDefaultFM ) +import CmdLineOpts ( opt_GlasgowExts ) \end{code} +%************************************************************************ +%* * +\subsection{Kind checking} +%* * +%************************************************************************ + \begin{code} -tcTyDecl :: RenamedTyDecl -> TcM s TyCon -\end{code} +kcTyDecl :: RenamedTyClDecl -> TcM s () + +kcTyDecl (TySynonym name tyvar_names rhs src_loc) + = tcLookupTy name `thenNF_Tc` \ (kind, _, _) -> + tcExtendTopTyVarScope kind tyvar_names $ \ _ result_kind -> + tcHsTypeKind rhs `thenTc` \ (rhs_kind, _) -> + unifyKind result_kind rhs_kind + +kcTyDecl (TyData _ context tycon_name tyvar_names con_decls _ _ src_loc) + = tcLookupTy tycon_name `thenNF_Tc` \ (kind, _, _) -> + tcExtendTopTyVarScope kind tyvar_names $ \ result_kind _ -> + tcContext context `thenTc_` + mapTc kcConDecl con_decls `thenTc_` + returnTc () + +kcConDecl (ConDecl _ _ ex_tvs ex_ctxt details loc) + = tcAddSrcLoc loc ( + tcExtendTyVarScope ex_tvs ( \ tyvars -> + tcContext ex_ctxt `thenTc_` + kc_con details `thenTc_` + returnTc () + )) + where + kc_con (VanillaCon btys) = mapTc kc_bty btys `thenTc_` returnTc () + kc_con (InfixCon bty1 bty2) = mapTc kc_bty [bty1,bty2] `thenTc_` returnTc () + kc_con (NewCon ty _) = kcHsType ty + kc_con (RecCon flds) = mapTc kc_field flds `thenTc_` returnTc () -Type synonym decls -~~~~~~~~~~~~~~~~~~ + kc_bty (Banged ty) = kcHsType ty + kc_bty (Unbanged ty) = kcHsType ty + kc_bty (Unpacked ty) = kcHsType ty -\begin{code} -tcTyDecl (TySynonym tycon_name tyvar_names rhs src_loc) - = tcAddSrcLoc src_loc $ - tcAddErrCtxt (tySynCtxt tycon_name) $ + kc_field (_, bty) = kc_bty bty +\end{code} - -- Look up the pieces - tcLookupTyCon tycon_name `thenNF_Tc` \ (tycon_kind, _, rec_tycon) -> - mapAndUnzipNF_Tc tcLookupTyVar tyvar_names `thenNF_Tc` \ (tyvar_kinds, rec_tyvars) -> - -- Look at the rhs - tcMonoTypeKind rhs `thenTc` \ (rhs_kind, rhs_ty) -> +%************************************************************************ +%* * +\subsection{Type checking} +%* * +%************************************************************************ - -- Unify tycon kind with (k1->...->kn->rhs) - unifyKind tycon_kind - (foldr mkTcArrowKind rhs_kind tyvar_kinds) - `thenTc_` +\begin{code} +tcTyDecl :: RecFlag -> FiniteMap Name ArgVrcs -> RenamedTyClDecl -> TcM s TyCon + +tcTyDecl is_rec rec_vrcs (TySynonym tycon_name tyvar_names rhs src_loc) + = tcLookupTy tycon_name `thenNF_Tc` \ (tycon_kind, Just arity, _) -> + tcExtendTopTyVarScope tycon_kind tyvar_names $ \ tyvars _ -> + tcHsTopTypeKind rhs `thenTc` \ (_, rhs_ty) -> + -- If the RHS mentions tyvars that aren't in scope, we'll + -- quantify over them. With gla-exts that's right, but for H98 + -- we should complain. We can't do that here without falling into + -- a black hole, so we do it in rnDecl (TySynonym case) let - -- Getting the TyCon's kind is a bit of a nuisance. We can't use the tycon_kind, - -- because that's a TcKind and may not yet be fully unified with other kinds. - -- We could have augmented the tycon environment with a knot-tied kind, - -- but the simplest thing to do seems to be to get the Kind by (lazily) - -- looking at the tyvars and rhs_ty. - result_kind, final_tycon_kind :: Kind -- NB not TcKind! - result_kind = typeKind rhs_ty - final_tycon_kind = foldr (mkArrowKind . tyVarKind) result_kind rec_tyvars - -- Construct the tycon - tycon = mkSynTyCon (getName tycon_name) - final_tycon_kind - (length tyvar_names) - rec_tyvars - rhs_ty + argvrcs = lookupWithDefaultFM rec_vrcs (pprPanic "tcTyDecl: argvrcs:" $ ppr tycon_name) + tycon_name + tycon = mkSynTyCon tycon_name tycon_kind arity tyvars rhs_ty argvrcs in returnTc tycon -\end{code} -Algebraic data and newtype decls -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -\begin{code} -tcTyDecl (TyData context tycon_name tyvar_names con_decls derivings pragmas src_loc) - = tcTyDataOrNew DataType context tycon_name tyvar_names con_decls derivings pragmas src_loc - -tcTyDecl (TyNew context tycon_name tyvar_names con_decl derivings pragmas src_loc) - = tcTyDataOrNew NewType context tycon_name tyvar_names con_decl derivings pragmas src_loc - - -tcTyDataOrNew data_or_new context tycon_name tyvar_names con_decls derivings pragmas src_loc - = tcAddSrcLoc src_loc $ - tcAddErrCtxt (tyDataCtxt tycon_name) $ +tcTyDecl is_rec rec_vrcs (TyData data_or_new context tycon_name tyvar_names con_decls derivings pragmas src_loc) + = -- Lookup the pieces + tcLookupTy tycon_name `thenNF_Tc` \ (tycon_kind, _, ATyCon rec_tycon) -> + tcExtendTopTyVarScope tycon_kind tyvar_names $ \ tyvars _ -> - -- Lookup the pieces - tcLookupTyCon tycon_name `thenNF_Tc` \ (tycon_kind, _, rec_tycon) -> - mapAndUnzipNF_Tc tcLookupTyVar tyvar_names `thenNF_Tc` \ (tyvar_kinds, rec_tyvars) -> - tc_derivs derivings `thenNF_Tc` \ derived_classes -> + -- Typecheck the pieces + tcContext context `thenTc` \ ctxt -> + let ctxt' = classesOfPreds ctxt in + mapTc (tcConDecl rec_tycon tyvars ctxt') con_decls `thenTc` \ data_cons -> + tc_derivs derivings `thenTc` \ derived_classes -> - -- Typecheck the context - tcContext context `thenTc` \ ctxt -> - - -- Unify tycon kind with (k1->...->kn->Type) - unifyKind tycon_kind - (foldr mkTcArrowKind mkTcTypeKind tyvar_kinds) - `thenTc_` - - -- Walk the condecls - mapTc (tcConDecl rec_tycon rec_tyvars ctxt) con_decls - `thenTc` \ con_ids -> let -- Construct the tycon - final_tycon_kind :: Kind -- NB not TcKind! - final_tycon_kind = foldr (mkArrowKind . tyVarKind) mkBoxedTypeKind rec_tyvars - - tycon = mkDataTyCon (getName tycon_name) - final_tycon_kind - rec_tyvars - ctxt - con_ids - derived_classes - data_or_new + flavour = case data_or_new of + NewType -> NewTyCon (mkNewTyConRep tycon) + DataType | all isNullaryDataCon data_cons -> EnumTyCon + | otherwise -> DataTyCon + + argvrcs = lookupWithDefaultFM rec_vrcs (pprPanic "tcTyDecl: argvrcs:" $ ppr tycon_name) + tycon_name + + tycon = mkAlgTyCon tycon_name tycon_kind tyvars ctxt' argvrcs + data_cons + derived_classes + flavour is_rec in returnTc tycon + where + tc_derivs Nothing = returnTc [] + tc_derivs (Just ds) = mapTc tc_deriv ds -tc_derivs Nothing = returnNF_Tc [] -tc_derivs (Just ds) = mapNF_Tc tc_deriv ds - -tc_deriv name - = tcLookupClass name `thenNF_Tc` \ (_, clas) -> - returnNF_Tc clas + tc_deriv name = tcLookupTy name `thenTc` \ (_, _, AClass clas) -> + returnTc clas \end{code} -Generating constructor/selector bindings for data declarations -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ - \begin{code} -mkDataBinds :: TyCon -> TcM s ([Id], TcHsBinds s) -mkDataBinds tycon - = ASSERT( isDataTyCon tycon ) - mapAndUnzipTc mkConstructor data_cons `thenTc` \ (con_ids, con_binds) -> - mapAndUnzipTc (mkRecordSelector tycon) groups `thenTc` \ (sel_ids, sel_binds) -> - returnTc (con_ids ++ sel_ids, - SingleBind $ NonRecBind $ - foldr AndMonoBinds - (foldr AndMonoBinds EmptyMonoBinds con_binds) - con_binds - ) - where - data_cons = tyConDataCons tycon - fields = [ (con, field) | con <- data_cons, - field <- dataConFieldLabels con - ] +mkNewTyConRep :: TyCon -> Type +-- Find the representation type for this newtype TyCon +-- The trick is to to deal correctly with recursive newtypes +-- such as newtype T = MkT T - -- groups is list of fields that share a common name - groups = equivClasses cmp_name fields - cmp_name (_, field1) (_, field2) - = fieldLabelName field1 `cmp` fieldLabelName field2 +mkNewTyConRep tc + = mkForAllTys tvs (loop [] (mkTyConApp tc (mkTyVarTys tvs))) + where + tvs = tyConTyVars tc + loop tcs ty = case splitAlgTyConApp_maybe ty of { + Nothing -> ty ; + Just (tc, tys, data_cons) | not (isNewTyCon tc) -> ty + | tc `elem` tcs -> unitTy + | otherwise -> + + case splitFunTy (applyTys (dataConRepType (head data_cons)) tys) of + (rep_ty, _) -> loop (tc:tcs) rep_ty + } \end{code} -We're going to build a constructor that looks like: - - data (Data a, C b) => T a b = T1 !a !Int b - - T1 = /\ a b -> - \d1::Data a, d2::C b -> - \p q r -> case p of { p -> - case q of { q -> - HsCon [a,b,c] [p,q,r]}} -Notice that - -* d2 is thrown away --- a context in a data decl is used to make sure - one *could* construct dictionaries at the site the constructor - is used, but the dictionary isn't actually used. - -* We have to check that we can construct Data dictionaries for - the types a and Int. Once we've done that we can throw d1 away too. - -* We use (case p of ...) to evaluate p, rather than "seq" because - all that matters is that the arguments are evaluated. "seq" is - very careful to preserve evaluation order, which we don't need - to be here. +%************************************************************************ +%* * +\subsection{Type check constructors} +%* * +%************************************************************************ \begin{code} -mkConstructor con_id - | not (isLocallyDefinedName (getName con_id)) - = returnTc (con_id, EmptyMonoBinds) - - | otherwise -- It is locally defined - = tcInstId con_id `thenNF_Tc` \ (tyvars, theta, tau) -> - newDicts DataDeclOrigin theta `thenNF_Tc` \ (_, dicts) -> - let - (arg_tys, result_ty) = splitFunTy tau - n_args = length arg_tys +tcConDecl :: TyCon -> [TyVar] -> [(Class,[Type])] -> RenamedConDecl -> TcM s DataCon + +tcConDecl tycon tyvars ctxt (ConDecl name wkr_name ex_tvs ex_ctxt details src_loc) + = tcAddSrcLoc src_loc $ + tcExtendTyVarScope ex_tvs $ \ ex_tyvars -> + tcContext ex_ctxt `thenTc` \ ex_theta -> + let + ex_ctxt' = classesOfPreds ex_theta in - newLocalIds (take n_args (repeat SLIT("con"))) arg_tys `thenNF_Tc` {- \ pre_zonk_args -> - mapNF_Tc zonkId pre_zonk_args `thenNF_Tc` -} \ args -> - - -- Check that all the types of all the strict - -- arguments are in Data. This is trivially true of everything except - -- type variables, for which we must check the context. - let - strict_marks = dataConStrictMarks con_id - strict_args = [arg | (arg, MarkedStrict) <- args `zipEqual` strict_marks] - - data_tyvars = -- The tyvars in the constructor's context that are arguments - -- to the Data class - [getTyVar "mkConstructor" ty - | (clas,ty) <- theta, - uniqueOf clas == evalClassKey] - - check_data arg = case getTyVar_maybe (tcIdType arg) of - Nothing -> returnTc () -- Not a tyvar, so OK - Just tyvar -> checkTc (tyvar `elem` data_tyvars) (missingDataErr tyvar) - in - mapTc check_data strict_args `thenTc_` + tc_con_decl_help tycon tyvars ctxt name wkr_name ex_tyvars ex_ctxt' details + +tc_con_decl_help tycon tyvars ctxt name wkr_name ex_tyvars ex_theta details + = case details of + VanillaCon btys -> tc_datacon btys + InfixCon bty1 bty2 -> tc_datacon [bty1,bty2] + NewCon ty mb_f -> tc_newcon ty mb_f + RecCon fields -> tc_rec_con fields + where + tc_datacon btys + = let + arg_stricts = map get_strictness btys + tys = map get_pty btys + in + mapTc tcHsTopType tys `thenTc` \ arg_tys -> + mk_data_con arg_stricts arg_tys [] + + tc_newcon ty mb_f + = tcHsTopBoxedType ty `thenTc` \ arg_ty -> + -- can't allow an unboxed type here, because we're effectively + -- going to remove the constructor while coercing it to a boxed type. + let + field_label = + case mb_f of + Nothing -> [] + Just f -> [mkFieldLabel (getName f) tycon arg_ty (head allFieldLabelTags)] + in + mk_data_con [notMarkedStrict] [arg_ty] field_label + + tc_rec_con fields + = checkTc (null ex_tyvars) (exRecConErr name) `thenTc_` + mapTc tc_field fields `thenTc` \ field_label_infos_s -> + let + field_label_infos = concat field_label_infos_s + arg_stricts = [strict | (_, _, strict) <- field_label_infos] + arg_tys = [ty | (_, ty, _) <- field_label_infos] + + field_labels = [ mkFieldLabel (getName name) tycon ty tag + | ((name, ty, _), tag) <- field_label_infos `zip` allFieldLabelTags ] + in + mk_data_con arg_stricts arg_tys field_labels + + tc_field (field_label_names, bty) + = tcHsTopType (get_pty bty) `thenTc` \ field_ty -> + returnTc [(name, field_ty, get_strictness bty) | name <- field_label_names] + + mk_data_con arg_stricts arg_tys fields + = -- Now we've checked all the field types we must + -- zonk the existential tyvars to finish the kind + -- inference on their kinds, and commit them to being + -- immutable type variables. (The top-level tyvars are + -- already fixed, by the preceding kind-inference pass.) + mapNF_Tc zonkTcTyVarToTyVar ex_tyvars `thenNF_Tc` \ ex_tyvars' -> + zonkTcClassConstraints ex_theta `thenNF_Tc` \ ex_theta' -> + let + data_con = mkDataCon name arg_stricts fields + tyvars (thinContext arg_tys ctxt) + ex_tyvars' ex_theta' + arg_tys + tycon data_con_id data_con_wrap_id + data_con_id = mkDataConId wkr_name data_con + data_con_wrap_id = mkDataConWrapId data_con + in + returnNF_Tc data_con - -- Build the data constructor - let - con_rhs = mkHsTyLam tyvars $ - mkHsDictLam dicts $ - mk_pat_match args $ - mk_case strict_args $ - HsCon con_id arg_tys (map HsVar args) +-- The context for a data constructor should be limited to +-- the type variables mentioned in the arg_tys +thinContext arg_tys ctxt + = filter in_arg_tys ctxt + where + arg_tyvars = tyVarsOfTypes arg_tys + in_arg_tys (clas,tys) = not $ isEmptyVarSet $ + tyVarsOfTypes tys `intersectVarSet` arg_tyvars + +get_strictness (Banged _) = markedStrict +get_strictness (Unbanged _) = notMarkedStrict +get_strictness (Unpacked _) = markedUnboxed - mk_pat_match [] body = body - mk_pat_match (arg:args) body = HsLam (PatMatch (VarPat arg) (SimpleMatch (mk_pat_match args body))) +get_pty (Banged ty) = ty +get_pty (Unbanged ty) = ty +get_pty (Unpacked ty) = ty +\end{code} - mk_case [] body = body - mk_case (arg:args) body = HsCase (HsVar arg) - [PatMatch (VarPat arg) (SimpleMatch (mk_case args body))] - src_loc - src_loc = nameSrcLoc (getName con_id) - in - returnTc (con_id, VarMonoBind (RealId con_id) con_rhs) -\end{code} +%************************************************************************ +%* * +\subsection{Generating constructor/selector bindings for data declarations} +%* * +%************************************************************************ -We're going to build a record selector that looks like this: +\begin{code} +mkImplicitDataBinds :: [TyCon] -> TcM s ([Id], TcMonoBinds) +mkImplicitDataBinds [] = returnTc ([], EmptyMonoBinds) +mkImplicitDataBinds (tycon : tycons) + | isSynTyCon tycon = mkImplicitDataBinds tycons + | otherwise = mkImplicitDataBinds_one tycon `thenTc` \ (ids1, b1) -> + mkImplicitDataBinds tycons `thenTc` \ (ids2, b2) -> + returnTc (ids1++ids2, b1 `AndMonoBinds` b2) + +mkImplicitDataBinds_one tycon + = mapTc (mkRecordSelector tycon) groups `thenTc` \ sel_ids -> + let + unf_ids = sel_ids ++ data_con_wrapper_ids + all_ids = map dataConId data_cons ++ unf_ids + + -- For the locally-defined things + -- we need to turn the unfoldings inside the selector Ids into bindings, + -- and build bindigns for the constructor wrappers + binds | isLocallyDefined tycon = idsToMonoBinds unf_ids + | otherwise = EmptyMonoBinds + in + returnTc (all_ids, binds) + where + data_cons = tyConDataCons tycon - data T a b c = T1 { op :: a, ...} - | T2 { op :: a, ...} - | T3 + data_con_wrapper_ids = map dataConWrapId data_cons - sel :: forall a b c. T a b c -> a - sel = /\ a b c -> \ T1 { sel = x } -> x - T2 { sel = 2 } -> x + fields = [ (con, field) | con <- data_cons, + field <- dataConFieldLabels con + ] -Note that the selector Id itself is used as the field -label; it has to be an Id, you see! + -- groups is list of fields that share a common name + groups = equivClasses cmp_name fields + cmp_name (_, field1) (_, field2) + = fieldLabelName field1 `compare` fieldLabelName field2 +\end{code} \begin{code} mkRecordSelector tycon fields@((first_con, first_field_label) : other_fields) - = let - field_ty = fieldLabelType first_field_label - field_name = fieldLabelName first_field_label - other_tys = [fieldLabelType fl | (_, fl) <- other_fields] - (tyvars, _, _, _) = dataConSig first_con - data_ty = applyTyCon tycon (mkTyVarTys tyvars) - -- tyvars of first_con may be free in field_ty - in - + -- These fields all have the same name, but are from + -- different constructors in the data type -- Check that all the fields in the group have the same type -- This check assumes that all the constructors of a given -- data type use the same type variables - checkTc (all (eqTy field_ty) other_tys) + = checkTc (all (== field_ty) other_tys) (fieldTypeMisMatch field_name) `thenTc_` - - -- Create an Id for the field itself - tcInstTyVars tyvars `thenNF_Tc` \ (tyvars', tyvar_tys, tenv) -> - tcInstType tenv field_ty `thenNF_Tc` \ field_ty' -> - let - data_ty' = applyTyCon tycon tyvar_tys - in - newLocalId SLIT("x") field_ty' `thenNF_Tc` \ field_id -> - newLocalId SLIT("r") data_ty' `thenNF_Tc` \ record_id -> - - -- Now build the selector - let - selector_ty :: Type - selector_ty = mkForAllTys tyvars $ - mkFunTy data_ty $ - field_ty - - selector_id :: Id - selector_id = mkRecordSelId first_field_label selector_ty - - -- HsSyn is dreadfully verbose for defining the selector! - selector_rhs = mkHsTyLam tyvars' $ - HsLam $ - PatMatch (VarPat record_id) $ - SimpleMatch $ - selector_body - - selector_body = HsCase (HsVar record_id) (map mk_match fields) (getSrcLoc tycon) - - mk_match (con_id, field_label) - = PatMatch (RecPat con_id data_ty' [(RealId selector_id, VarPat field_id, False)]) $ - SimpleMatch $ - HsVar field_id - in - returnTc (selector_id, if isLocallyDefinedName (getName tycon) - then VarMonoBind (RealId selector_id) selector_rhs - else EmptyMonoBinds) -\end{code} - -Constructors -~~~~~~~~~~~~ -\begin{code} -tcConDecl :: TyCon -> [TyVar] -> [(Class,Type)] -> RenamedConDecl -> TcM s Id - -tcConDecl tycon tyvars ctxt (ConDecl name btys src_loc) - = tcDataCon tycon tyvars ctxt name btys src_loc - -tcConDecl tycon tyvars ctxt (ConOpDecl bty1 op bty2 src_loc) - = tcDataCon tycon tyvars ctxt op [bty1,bty2] src_loc - -tcConDecl tycon tyvars ctxt (NewConDecl name ty src_loc) - = tcAddSrcLoc src_loc $ - tcMonoType ty `thenTc` \ arg_ty -> - let - data_con = mkDataCon (getName name) - [NotMarkedStrict] - [{- No labelled fields -}] - tyvars - ctxt - [arg_ty] - tycon - -- nullSpecEnv - in - returnTc data_con - -tcConDecl tycon tyvars ctxt (RecConDecl name fields src_loc) - = tcAddSrcLoc src_loc $ - mapTc tcField fields `thenTc` \ field_label_infos_s -> - let - field_label_infos = concat field_label_infos_s - stricts = [strict | (_, _, strict) <- field_label_infos] - arg_tys = [ty | (_, ty, _) <- field_label_infos] - - field_labels = [ mkFieldLabel (getName name) ty tag - | ((name, ty, _), tag) <- field_label_infos `zip` allFieldLabelTags - ] - - data_con = mkDataCon (getName name) - stricts - field_labels - tyvars - (thinContext arg_tys ctxt) - arg_tys - tycon - -- nullSpecEnv - in - returnTc data_con - -tcField (field_label_names, bty) - = tcMonoType (get_ty bty) `thenTc` \ field_ty -> - returnTc [(name, field_ty, get_strictness bty) | name <- field_label_names] - -tcDataCon tycon tyvars ctxt name btys src_loc - = tcAddSrcLoc src_loc $ - let - stricts = map get_strictness btys - tys = map get_ty btys - in - mapTc tcMonoType tys `thenTc` \ arg_tys -> - let - data_con = mkDataCon (getName name) - stricts - [{- No field labels -}] - tyvars - (thinContext arg_tys ctxt) - arg_tys - tycon - -- nullSpecEnv - in - returnTc data_con - --- The context for a data constructor should be limited to --- the type variables mentioned in the arg_tys -thinContext arg_tys ctxt - = filter in_arg_tys ctxt + returnTc (mkRecordSelId tycon first_field_label) where - arg_tyvars = tyVarsOfTypes arg_tys - in_arg_tys (clas,ty) = getTyVar "tcDataCon" ty `elementOfTyVarSet` arg_tyvars - -get_strictness (Banged ty) = MarkedStrict -get_strictness (Unbanged ty) = NotMarkedStrict - -get_ty (Banged ty) = ty -get_ty (Unbanged ty) = ty + field_ty = fieldLabelType first_field_label + field_name = fieldLabelName first_field_label + other_tys = [fieldLabelType fl | (_, fl) <- other_fields] \end{code} - Errors and contexts ~~~~~~~~~~~~~~~~~~~ \begin{code} -tySynCtxt tycon_name sty - = ppCat [ppStr "In the type declaration for", ppr sty tycon_name] - -tyDataCtxt tycon_name sty - = ppCat [ppStr "In the data declaration for", ppr sty tycon_name] - -tyNewCtxt tycon_name sty - = ppCat [ppStr "In the newtype declaration for", ppr sty tycon_name] - -fieldTypeMisMatch field_name sty - = ppSep [ppStr "Declared types differ for field", ppr sty field_name] +fieldTypeMisMatch field_name + = sep [ptext SLIT("Declared types differ for field"), quotes (ppr field_name)] -missingDataErr tyvar sty - = ppStr "Missing `data' (???)" -- ToDo: improve +exRecConErr name + = ptext SLIT("Can't combine named fields with locally-quantified type variables") + $$ + (ptext SLIT("In the declaration of data constructor") <+> ppr name) \end{code}