%
-% (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,
+ mkDataBinds
) 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 )
+import BasicTypes ( RecFlag(..), NewOrData(..), StrictnessMark(..) )
+
+import TcMonoType ( tcExtendTopTyVarScope, tcExtendTyVarScope,
+ tcHsTypeKind, tcHsType, tcHsTopType, tcHsTopBoxedType,
+ tcContext
+ )
+import TcType ( zonkTcTyVarToTyVar, zonkTcThetaType )
+import TcEnv ( tcLookupTy, 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, dataConSig, mkDataCon, isNullaryDataCon,
+ dataConFieldLabels, dataConId
+ )
+import MkId ( mkDataConId, mkRecordSelId )
+import Id ( getIdUnfolding )
+import CoreUnfold ( getUnfoldingTemplate )
+import FieldLabel
+import Var ( Id, TyVar )
+import Name ( isLocallyDefined, OccName, NamedThing(..) )
+import Outputable
+import TyCon ( TyCon, mkSynTyCon, mkAlgTyCon, isAlgTyCon,
+ isSynTyCon, tyConDataCons
+ )
+import Type ( getTyVar, tyVarsOfTypes,
+ mkTyConApp, mkTyVarTys, mkForAllTys, mkFunTy,
+ mkTyVarTy,
+ mkArrowKind, mkArrowKinds, boxedTypeKind,
+ isUnboxedType, Type, ThetaType
+ )
+import Var ( tyVarKind )
+import VarSet ( intersectVarSet, isEmptyVarSet )
+import Util ( equivClasses )
\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) = tcHsType ty `thenTc_` returnTc ()
+ kc_con (RecCon flds) = mapTc kc_field flds `thenTc_` returnTc ()
-Type synonym decls
-~~~~~~~~~~~~~~~~~~
+ kc_bty (Banged ty) = tcHsType ty
+ kc_bty (Unbanged ty) = tcHsType 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 -> RenamedTyClDecl -> TcM s TyCon
+
+tcTyDecl is_rec (TySynonym tycon_name tyvar_names rhs src_loc)
+ = tcLookupTy tycon_name `thenNF_Tc` \ (tycon_kind, Just arity, _) ->
+ tcExtendTopTyVarScope tycon_kind tyvar_names $ \ tyvars _ ->
+ tcHsTopType rhs `thenTc` \ rhs_ty ->
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
+ tycon = mkSynTyCon tycon_name tycon_kind arity tyvars rhs_ty
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
+tcTyDecl is_rec (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 _ ->
-tcTyDataOrNew data_or_new context tycon_name tyvar_names con_decls derivings pragmas src_loc
- = tcAddSrcLoc src_loc $
- tcAddErrCtxt (tyDataCtxt tycon_name) $
+ -- Typecheck the pieces
+ tcContext context `thenTc` \ ctxt ->
+ mapTc (tcConDecl rec_tycon tyvars ctxt) con_decls `thenTc` \ data_cons ->
+ tc_derivs derivings `thenTc` \ derived_classes ->
- -- 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 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 . 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
+ real_data_or_new = case data_or_new of
+ NewType -> NewType
+ DataType | all isNullaryDataCon data_cons -> EnumType
+ | otherwise -> DataType
+
+ tycon = mkAlgTyCon tycon_name tycon_kind tyvars ctxt
+ data_cons
+ derived_classes
+ Nothing -- Not a dictionary
+ real_data_or_new is_rec
in
returnTc 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
-
-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
+%************************************************************************
+%* *
+\subsection{Type check constructors}
+%* *
+%************************************************************************
-tcConDecl tycon tyvars ctxt (ConOpDecl bty1 op bty2 src_loc)
- = tcAddSrcLoc src_loc $
- let
- (stricts, tys) = sep_bangs [bty1, bty2]
- in
- mapTc tcMonoType tys `thenTc` \ arg_tys ->
- let
- data_con = mkDataCon (getItsUnique op)
- (getNameFullName op)
- stricts
- tyvars
- [] -- ToDo: ctxt
+\begin{code}
+tcConDecl :: TyCon -> [TyVar] -> ThetaType -> RenamedConDecl -> TcM s DataCon
+
+tcConDecl tycon tyvars ctxt (ConDecl name ex_tvs ex_ctxt details src_loc)
+ = tcAddSrcLoc src_loc $
+ tcExtendTyVarScope ex_tvs $ \ ex_tyvars ->
+ tcContext ex_ctxt `thenTc` \ ex_theta ->
+ tc_con_decl_help tycon tyvars ctxt name ex_tyvars ex_theta details
+
+tc_con_decl_help tycon tyvars ctxt name ex_tyvars ex_theta details
+ = case details of
+ VanillaCon btys -> tc_datacon btys
+ InfixCon bty1 bty2 -> tc_datacon [bty1,bty2]
+ NewCon ty -> tc_newcon ty
+ 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
+ = 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.
+ mk_data_con [NotMarkedStrict] [arg_ty] []
+
+ 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) 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' ->
+ zonkTcThetaType 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_id = mkDataConId 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_pty (Banged ty) = ty
+get_pty (Unbanged ty) = ty
+\end{code}
-tcConDecl tycon tyvars ctxt (NewConDecl name ty src_loc)
- = tcAddSrcLoc src_loc $
- tcMonoType ty `thenTc` \ arg_ty ->
- let
- data_con = mkDataCon (getItsUnique name)
- (getNameFullName name)
- [NotMarkedStrict]
- tyvars
- [] -- ToDo: ctxt
- [arg_ty]
- tycon
- -- nullSpecEnv
- in
- returnTc data_con
-tcConDecl tycon tyvars ctxt (RecConDecl con fields src_loc)
- = panic "tcConDecls:RecConDecl"
+%************************************************************************
+%* *
+\subsection{Generating constructor/selector bindings for data declarations}
+%* *
+%************************************************************************
-sep_bangs btys
- = unzip (map sep_bang btys)
- where
- sep_bang (Banged ty) = (MarkedStrict, ty)
- sep_bang (Unbanged ty) = (NotMarkedStrict, ty)
+\begin{code}
+mkDataBinds :: [TyCon] -> TcM s ([Id], TcMonoBinds)
+mkDataBinds [] = returnTc ([], EmptyMonoBinds)
+mkDataBinds (tycon : tycons)
+ | isSynTyCon tycon = mkDataBinds tycons
+ | otherwise = mkDataBinds_one tycon `thenTc` \ (ids1, b1) ->
+ mkDataBinds tycons `thenTc` \ (ids2, b2) ->
+ returnTc (ids1++ids2, b1 `AndMonoBinds` b2)
+
+mkDataBinds_one tycon
+ = ASSERT( isAlgTyCon tycon )
+ mapTc (mkRecordSelector tycon) groups `thenTc` \ sel_ids ->
+ let
+ data_ids = map dataConId data_cons ++ sel_ids
+
+ -- For the locally-defined things
+ -- we need to turn the unfoldings inside the Ids into bindings,
+ binds = [ CoreMonoBind data_id (getUnfoldingTemplate (getIdUnfolding data_id))
+ | data_id <- data_ids, isLocallyDefined data_id
+ ]
+ in
+ returnTc (data_ids, andMonoBindList binds)
+ where
+ data_cons = tyConDataCons tycon
+ fields = [ (con, field) | con <- data_cons,
+ field <- dataConFieldLabels con
+ ]
+
+ -- 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_`
+ returnTc selector_id
+ where
+ 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 = mkTyConApp tycon (mkTyVarTys tyvars)
+ -- tyvars of first_con may be free in field_ty
+ -- Now build the selector
+
+ selector_ty :: Type
+ selector_ty = mkForAllTys tyvars $
+ mkFunTy data_ty $
+ field_ty
+
+ selector_id :: Id
+ selector_id = mkRecordSelId first_field_label selector_ty
+\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}