%
-% (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,
- tcConDecl
+ tcTyDecl, kcTyDecl,
+ tcConDecl,
+ mkImplicitDataBinds, mkNewTyConRep
) where
-import Ubiq{-uitous-}
-
-import HsSyn ( TyDecl(..), ConDecl(..), BangType(..), MonoType )
-import RnHsSyn ( RenamedTyDecl(..), RenamedConDecl(..) )
+#include "HsVersions.h"
-import TcMonoType ( tcMonoTypeKind, tcMonoType, tcContext )
-import TcEnv ( tcLookupTyCon, tcLookupTyVar, tcLookupClass )
+import HsSyn ( MonoBinds(..),
+ TyClDecl(..), ConDecl(..), ConDetails(..), BangType(..),
+ andMonoBindList
+ )
+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, tcLookupValueByKey, TcTyThing(..) )
import TcMonad
-import TcKind ( TcKind, unifyKind, mkTcArrowKind, mkTcTypeKind )
-
-import Id ( mkDataCon, StrictnessMark(..) )
-import Kind ( Kind, mkArrowKind, mkBoxedTypeKind )
-import SpecEnv ( SpecEnv(..), nullSpecEnv )
-import Name ( getNameFullName, Name(..) )
-import Pretty
-import TyCon ( TyCon, ConsVisible(..), NewOrData(..), mkSynTyCon, mkDataTyCon )
-import Type ( getTypeKind )
-import TyVar ( getTyVarKind )
-import Util ( panic )
-
+import TcUnify ( unifyKind )
+
+import Class ( Class )
+import DataCon ( DataCon, mkDataCon, isNullaryDataCon,
+ dataConFieldLabels, dataConId, dataConWrapId,
+ markedStrict, notMarkedStrict, markedUnboxed, dataConRepType
+ )
+import MkId ( mkDataConId, mkDataConWrapId, mkRecordSelId )
+import FieldLabel
+import Var ( Id, TyVar )
+import Name ( Name, isLocallyDefined, OccName, NamedThing(..), nameUnique )
+import Outputable
+import TyCon ( TyCon, AlgTyConFlavour(..), ArgVrcs, mkSynTyCon, mkAlgTyCon,
+ tyConDataConsIfAvailable, tyConTyVars,
+ isSynTyCon, isNewTyCon
+ )
+import Type ( getTyVar, tyVarsOfTypes, splitFunTy, applyTys,
+ mkTyConApp, mkTyVarTys, mkForAllTys, mkFunTy,
+ mkTyVarTy, splitAlgTyConApp_maybe,
+ mkArrowKind, mkArrowKinds, boxedTypeKind,
+ isUnboxedType, Type, ThetaType, classesOfPreds
+ )
+import TysWiredIn ( unitTy )
+import Var ( tyVarKind )
+import VarSet ( intersectVarSet, isEmptyVarSet )
+import Unique ( unpackCStringIdKey )
+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 (Name, TcTyThing)
+
+tcTyDecl is_rec rec_vrcs (TySynonym tycon_name tyvar_names rhs src_loc)
+ = tcLookupTy tycon_name `thenNF_Tc` \ (tycon_kind, ASynTyCon _ 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
-- Construct the tycon
- result_kind, final_tycon_kind :: Kind -- NB not TcKind!
- result_kind = getTypeKind rhs_ty
- final_tycon_kind = foldr (mkArrowKind . getTyVarKind) result_kind rec_tyvars
-
- tycon = mkSynTyCon (getItsUnique tycon_name)
- (getNameFullName 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
-
+ returnTc (tycon_name, ASynTyCon tycon arity)
-tcTyDataOrNew data_or_new context tycon_name tyvar_names con_decls derivings pragmas src_loc
- = tcAddSrcLoc src_loc $
- tcAddErrCtxt (tyDataCtxt tycon_name) $
- -- 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 ->
+tcTyDecl is_rec rec_vrcs (TyData data_or_new context tycon_name tyvar_names con_decls nconstrs derivings pragmas src_loc)
+ = -- Lookup the pieces
+ tcLookupTy tycon_name `thenNF_Tc` \ (tycon_kind, ADataTyCon rec_tycon) ->
+ tcExtendTopTyVarScope tycon_kind tyvar_names $ \ tyvars _ ->
- -- Typecheck the context
- tcContext context `thenTc` \ ctxt ->
+ -- 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 ->
- -- 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 . getTyVarKind) mkBoxedTypeKind rec_tyvars
-
- tycon = mkDataTyCon (getItsUnique tycon_name)
- final_tycon_kind
- (getNameFullName tycon_name)
- rec_tyvars
- ctxt
- con_ids
- derived_classes
- ConsVisible -- For now; if constrs are from pragma we are *abstract*
- 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 nconstrs
+ derived_classes
+ flavour is_rec
in
- returnTc tycon
+ returnTc (tycon_name, ADataTyCon tycon)
where
- tc_derivs Nothing = returnNF_Tc []
- tc_derivs (Just ds) = mapNF_Tc tc_deriv ds
+ tc_derivs Nothing = returnTc []
+ tc_derivs (Just ds) = mapTc 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}
-
-Constructors
-~~~~~~~~~~~~
\begin{code}
-tcConDecl :: TyCon -> [TyVar] -> [(Class,Type)] -> RenamedConDecl -> TcM s Id
+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
-tcConDecl tycon tyvars ctxt (ConDecl name btys src_loc)
- = tcAddSrcLoc src_loc $
- let
- (stricts, tys) = sep_bangs btys
- in
- mapTc tcMonoType tys `thenTc` \ arg_tys ->
- let
- data_con = mkDataCon (getItsUnique name)
- (getNameFullName name)
- stricts
- tyvars
- [] -- ToDo: ctxt; limited to tyvars in arg_tys
- arg_tys
- tycon
- -- nullSpecEnv
- in
- returnTc data_con
+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}
-tcConDecl tycon tyvars ctxt (ConOpDecl bty1 op bty2 src_loc)
- = tcAddSrcLoc src_loc $
- let
- (stricts, tys) = sep_bangs [bty1, bty2]
+
+%************************************************************************
+%* *
+\subsection{Type check constructors}
+%* *
+%************************************************************************
+
+\begin{code}
+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
- mapTc tcMonoType tys `thenTc` \ arg_tys ->
- let
- data_con = mkDataCon (getItsUnique op)
- (getNameFullName op)
- stricts
- tyvars
- [] -- ToDo: ctxt
+ 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
- -- nullSpecEnv
- in
- returnTc data_con
+ 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
+
+-- 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
+
+get_pty (Banged ty) = ty
+get_pty (Unbanged ty) = ty
+get_pty (Unpacked ty) = ty
+\end{code}
+
+
-tcConDecl tycon tyvars ctxt (NewConDecl name ty src_loc)
- = tcAddSrcLoc src_loc $
- tcMonoType ty `thenTc` \ arg_ty ->
+%************************************************************************
+%* *
+\subsection{Generating constructor/selector bindings for data declarations}
+%* *
+%************************************************************************
+
+\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
- data_con = mkDataCon (getItsUnique name)
- (getNameFullName name)
- [NotMarkedStrict]
- tyvars
- [] -- ToDo: ctxt
- [arg_ty]
- tycon
- -- nullSpecEnv
- in
- returnTc data_con
+ 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 = tyConDataConsIfAvailable tycon
+ -- Abstract types mean we don't bring the
+ -- data cons into scope, which should be fine
-tcConDecl tycon tyvars ctxt (RecConDecl con fields src_loc)
- = panic "tcConDecls:RecConDecl"
+ data_con_wrapper_ids = map dataConWrapId data_cons
+ fields = [ (con, field) | con <- data_cons,
+ field <- dataConFieldLabels con
+ ]
-sep_bangs btys
- = unzip (map sep_bang btys)
- where
- sep_bang (Banged ty) = (MarkedStrict, ty)
- sep_bang (Unbanged ty) = (NotMarkedStrict, ty)
+ -- 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)
+ -- 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 (== field_ty) other_tys)
+ (fieldTypeMisMatch field_name) `thenTc_`
+ tcLookupValueByKey unpackCStringIdKey `thenTc` \ unpack_id ->
+ returnTc (mkRecordSelId tycon first_field_label unpack_id)
+ where
+ 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]
+fieldTypeMisMatch field_name
+ = sep [ptext SLIT("Declared types differ for field"), quotes (ppr field_name)]
-tyNewCtxt tycon_name sty
- = ppCat [ppStr "In the newtype declaration for", ppr sty tycon_name]
+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}
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