2 % (c) The AQUA Project, Glasgow University, 1996-1998
4 \section[TcTyDecls]{Typecheck type declarations}
13 #include "HsVersions.h"
15 import HsSyn ( MonoBinds(..),
16 TyClDecl(..), ConDecl(..), ConDetails(..), BangType(..),
19 import RnHsSyn ( RenamedTyClDecl, RenamedConDecl )
20 import TcHsSyn ( TcMonoBinds )
21 import BasicTypes ( RecFlag(..), NewOrData(..) )
23 import TcMonoType ( tcExtendTopTyVarScope, tcExtendTyVarScope,
24 tcHsTypeKind, tcHsType, tcHsTopType, tcHsTopBoxedType,
25 tcContext, tcHsTopTypeKind
27 import TcType ( zonkTcTyVarToTyVar, zonkTcThetaType )
28 import TcEnv ( tcLookupTy, TcTyThing(..) )
30 import TcUnify ( unifyKind )
32 import Class ( Class )
33 import DataCon ( DataCon, dataConSig, mkDataCon, isNullaryDataCon,
34 dataConFieldLabels, dataConId,
35 markedStrict, notMarkedStrict, markedUnboxed
37 import MkId ( mkDataConId, mkRecordSelId, mkNewTySelId )
38 import Id ( getIdUnfolding )
39 import CoreUnfold ( getUnfoldingTemplate )
41 import Var ( Id, TyVar )
42 import Name ( Name, isLocallyDefined, OccName, NamedThing(..), nameUnique )
44 import TyCon ( TyCon, ArgVrcs, mkSynTyCon, mkAlgTyCon, isAlgTyCon,
45 isSynTyCon, tyConDataCons, isNewTyCon
47 import Type ( getTyVar, tyVarsOfTypes,
48 mkTyConApp, mkTyVarTys, mkForAllTys, mkFunTy,
50 mkArrowKind, mkArrowKinds, boxedTypeKind,
51 isUnboxedType, Type, ThetaType
53 import Var ( tyVarKind )
54 import VarSet ( intersectVarSet, isEmptyVarSet )
55 import Util ( equivClasses )
56 import FiniteMap ( FiniteMap, lookupWithDefaultFM )
59 %************************************************************************
61 \subsection{Kind checking}
63 %************************************************************************
66 kcTyDecl :: RenamedTyClDecl -> TcM s ()
68 kcTyDecl (TySynonym name tyvar_names rhs src_loc)
69 = tcLookupTy name `thenNF_Tc` \ (kind, _, _) ->
70 tcExtendTopTyVarScope kind tyvar_names $ \ _ result_kind ->
71 tcHsTypeKind rhs `thenTc` \ (rhs_kind, _) ->
72 unifyKind result_kind rhs_kind
74 kcTyDecl (TyData _ context tycon_name tyvar_names con_decls _ _ src_loc)
75 = tcLookupTy tycon_name `thenNF_Tc` \ (kind, _, _) ->
76 tcExtendTopTyVarScope kind tyvar_names $ \ result_kind _ ->
77 tcContext context `thenTc_`
78 mapTc kcConDecl con_decls `thenTc_`
81 kcConDecl (ConDecl _ ex_tvs ex_ctxt details loc)
83 tcExtendTyVarScope ex_tvs ( \ tyvars ->
84 tcContext ex_ctxt `thenTc_`
85 kc_con details `thenTc_`
89 kc_con (VanillaCon btys) = mapTc kc_bty btys `thenTc_` returnTc ()
90 kc_con (InfixCon bty1 bty2) = mapTc kc_bty [bty1,bty2] `thenTc_` returnTc ()
91 kc_con (NewCon ty _) = tcHsType ty `thenTc_` returnTc ()
92 kc_con (RecCon flds) = mapTc kc_field flds `thenTc_` returnTc ()
94 kc_bty (Banged ty) = tcHsType ty
95 kc_bty (Unbanged ty) = tcHsType ty
96 kc_bty (Unpacked ty) = tcHsType ty
98 kc_field (_, bty) = kc_bty bty
102 %************************************************************************
104 \subsection{Type checking}
106 %************************************************************************
109 tcTyDecl :: RecFlag -> FiniteMap Name ArgVrcs -> RenamedTyClDecl -> TcM s TyCon
111 tcTyDecl is_rec rec_vrcs (TySynonym tycon_name tyvar_names rhs src_loc)
112 = tcLookupTy tycon_name `thenNF_Tc` \ (tycon_kind, Just arity, _) ->
113 tcExtendTopTyVarScope tycon_kind tyvar_names $ \ tyvars _ ->
114 tcHsTopTypeKind rhs `thenTc` \ (_, rhs_ty) ->
116 -- Construct the tycon
117 argvrcs = lookupWithDefaultFM rec_vrcs (pprPanic "tcTyDecl: argvrcs:" $ ppr tycon_name)
119 tycon = mkSynTyCon tycon_name tycon_kind arity tyvars rhs_ty argvrcs
124 tcTyDecl is_rec rec_vrcs (TyData data_or_new context tycon_name tyvar_names con_decls derivings pragmas src_loc)
125 = -- Lookup the pieces
126 tcLookupTy tycon_name `thenNF_Tc` \ (tycon_kind, _, ATyCon rec_tycon) ->
127 tcExtendTopTyVarScope tycon_kind tyvar_names $ \ tyvars _ ->
129 -- Typecheck the pieces
130 tcContext context `thenTc` \ ctxt ->
131 mapTc (tcConDecl rec_tycon tyvars ctxt) con_decls `thenTc` \ data_cons ->
132 tc_derivs derivings `thenTc` \ derived_classes ->
135 -- Construct the tycon
136 real_data_or_new = case data_or_new of
138 DataType | all isNullaryDataCon data_cons -> EnumType
139 | otherwise -> DataType
141 argvrcs = lookupWithDefaultFM rec_vrcs (pprPanic "tcTyDecl: argvrcs:" $ ppr tycon_name)
144 tycon = mkAlgTyCon tycon_name tycon_kind tyvars ctxt argvrcs
147 Nothing -- Not a dictionary
148 real_data_or_new is_rec
152 tc_derivs Nothing = returnTc []
153 tc_derivs (Just ds) = mapTc tc_deriv ds
155 tc_deriv name = tcLookupTy name `thenTc` \ (_, _, AClass clas) ->
160 %************************************************************************
162 \subsection{Type check constructors}
164 %************************************************************************
167 tcConDecl :: TyCon -> [TyVar] -> ThetaType -> RenamedConDecl -> TcM s DataCon
169 tcConDecl tycon tyvars ctxt (ConDecl name ex_tvs ex_ctxt details src_loc)
170 = tcAddSrcLoc src_loc $
171 tcExtendTyVarScope ex_tvs $ \ ex_tyvars ->
172 tcContext ex_ctxt `thenTc` \ ex_theta ->
173 tc_con_decl_help tycon tyvars ctxt name ex_tyvars ex_theta details
175 tc_con_decl_help tycon tyvars ctxt name ex_tyvars ex_theta details
177 VanillaCon btys -> tc_datacon btys
178 InfixCon bty1 bty2 -> tc_datacon [bty1,bty2]
179 NewCon ty mb_f -> tc_newcon ty mb_f
180 RecCon fields -> tc_rec_con fields
184 arg_stricts = map get_strictness btys
185 tys = map get_pty btys
187 mapTc tcHsTopType tys `thenTc` \ arg_tys ->
188 mk_data_con arg_stricts arg_tys []
191 = tcHsTopBoxedType ty `thenTc` \ arg_ty ->
192 -- can't allow an unboxed type here, because we're effectively
193 -- going to remove the constructor while coercing it to a boxed type.
198 Just f -> [mkFieldLabel (getName f) arg_ty (head allFieldLabelTags)]
200 mk_data_con [notMarkedStrict] [arg_ty] field_label
203 = checkTc (null ex_tyvars) (exRecConErr name) `thenTc_`
204 mapTc tc_field fields `thenTc` \ field_label_infos_s ->
206 field_label_infos = concat field_label_infos_s
207 arg_stricts = [strict | (_, _, strict) <- field_label_infos]
208 arg_tys = [ty | (_, ty, _) <- field_label_infos]
210 field_labels = [ mkFieldLabel (getName name) ty tag
211 | ((name, ty, _), tag) <- field_label_infos `zip` allFieldLabelTags ]
213 mk_data_con arg_stricts arg_tys field_labels
215 tc_field (field_label_names, bty)
216 = tcHsTopType (get_pty bty) `thenTc` \ field_ty ->
217 returnTc [(name, field_ty, get_strictness bty) | name <- field_label_names]
219 mk_data_con arg_stricts arg_tys fields
220 = -- Now we've checked all the field types we must
221 -- zonk the existential tyvars to finish the kind
222 -- inference on their kinds, and commit them to being
223 -- immutable type variables. (The top-level tyvars are
224 -- already fixed, by the preceding kind-inference pass.)
225 mapNF_Tc zonkTcTyVarToTyVar ex_tyvars `thenNF_Tc` \ ex_tyvars' ->
226 zonkTcThetaType ex_theta `thenNF_Tc` \ ex_theta' ->
228 data_con = mkDataCon name arg_stricts fields
229 tyvars (thinContext arg_tys ctxt)
233 data_con_id = mkDataConId data_con
237 -- The context for a data constructor should be limited to
238 -- the type variables mentioned in the arg_tys
239 thinContext arg_tys ctxt
240 = filter in_arg_tys ctxt
242 arg_tyvars = tyVarsOfTypes arg_tys
243 in_arg_tys (clas,tys) = not $ isEmptyVarSet $
244 tyVarsOfTypes tys `intersectVarSet` arg_tyvars
246 get_strictness (Banged _) = markedStrict
247 get_strictness (Unbanged _) = notMarkedStrict
248 get_strictness (Unpacked _) = markedUnboxed
250 get_pty (Banged ty) = ty
251 get_pty (Unbanged ty) = ty
252 get_pty (Unpacked ty) = ty
257 %************************************************************************
259 \subsection{Generating constructor/selector bindings for data declarations}
261 %************************************************************************
264 mkDataBinds :: [TyCon] -> TcM s ([Id], TcMonoBinds)
265 mkDataBinds [] = returnTc ([], EmptyMonoBinds)
266 mkDataBinds (tycon : tycons)
267 | isSynTyCon tycon = mkDataBinds tycons
268 | otherwise = mkDataBinds_one tycon `thenTc` \ (ids1, b1) ->
269 mkDataBinds tycons `thenTc` \ (ids2, b2) ->
270 returnTc (ids1++ids2, b1 `AndMonoBinds` b2)
272 mkDataBinds_one tycon
273 = mapTc (mkRecordSelector tycon) groups `thenTc` \ sel_ids ->
275 data_ids = map dataConId data_cons ++ sel_ids
277 -- For the locally-defined things
278 -- we need to turn the unfoldings inside the Ids into bindings,
279 binds | isLocallyDefined tycon
280 = [ CoreMonoBind data_id (getUnfoldingTemplate (getIdUnfolding data_id))
281 | data_id <- data_ids, isLocallyDefined data_id
286 returnTc (data_ids, andMonoBindList binds)
288 data_cons = tyConDataCons tycon
289 fields = [ (con, field) | con <- data_cons,
290 field <- dataConFieldLabels con
293 -- groups is list of fields that share a common name
294 groups = equivClasses cmp_name fields
295 cmp_name (_, field1) (_, field2)
296 = fieldLabelName field1 `compare` fieldLabelName field2
300 mkRecordSelector tycon fields@((first_con, first_field_label) : other_fields)
301 -- These fields all have the same name, but are from
302 -- different constructors in the data type
303 -- Check that all the fields in the group have the same type
304 -- This check assumes that all the constructors of a given
305 -- data type use the same type variables
306 = (if null other_fields then (\x->x) else
307 let lbls = [fieldLabelName f | (_,f) <- fields]
308 uniqs = [nameUnique l | l <- lbls]
311 pprTrace "mkRecordSelector" (vcat [ppr fields,
314 hsep [text (show (field_name `compare` fieldLabelName f)) | (_,f) <- fields]
317 checkTc (all (== field_ty) other_tys)
318 (fieldTypeMisMatch field_name) `thenTc_`
321 field_ty = fieldLabelType first_field_label
322 field_name = fieldLabelName first_field_label
323 other_tys = [fieldLabelType fl | (_, fl) <- other_fields]
324 (tyvars, _, _, _, _, _) = dataConSig first_con
325 data_ty = mkTyConApp tycon (mkTyVarTys tyvars)
326 -- tyvars of first_con may be free in field_ty
327 -- Now build the selector
330 selector_ty = mkForAllTys tyvars $
336 | isNewTyCon tycon = mkNewTySelId first_field_label selector_ty
337 | otherwise = mkRecordSelId first_field_label selector_ty
344 fieldTypeMisMatch field_name
345 = sep [ptext SLIT("Declared types differ for field"), quotes (ppr field_name)]
348 = ptext SLIT("Can't combine named fields with locally-quantified type variables")
350 (ptext SLIT("In the declaration of data constructor") <+> ppr name)