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(..), StrictnessMark(..) )
23 import TcMonoType ( tcExtendTopTyVarScope, tcExtendTyVarScope,
24 tcHsTypeKind, tcHsType, tcHsTopType, tcHsTopBoxedType,
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
36 import MkId ( mkDataConId, mkRecordSelId, mkNewTySelId )
37 import Id ( getIdUnfolding )
38 import CoreUnfold ( getUnfoldingTemplate )
40 import Var ( Id, TyVar )
41 import Name ( Name, isLocallyDefined, OccName, NamedThing(..) )
43 import TyCon ( TyCon, ArgVrcs, mkSynTyCon, mkAlgTyCon, isAlgTyCon,
44 isSynTyCon, tyConDataCons, isNewTyCon
46 import Type ( getTyVar, tyVarsOfTypes,
47 mkTyConApp, mkTyVarTys, mkForAllTys, mkFunTy,
49 mkArrowKind, mkArrowKinds, boxedTypeKind,
50 isUnboxedType, Type, ThetaType
52 import Var ( tyVarKind )
53 import VarSet ( intersectVarSet, isEmptyVarSet )
54 import Util ( equivClasses )
55 import FiniteMap ( FiniteMap, lookupWithDefaultFM )
58 %************************************************************************
60 \subsection{Kind checking}
62 %************************************************************************
65 kcTyDecl :: RenamedTyClDecl -> TcM s ()
67 kcTyDecl (TySynonym name tyvar_names rhs src_loc)
68 = tcLookupTy name `thenNF_Tc` \ (kind, _, _) ->
69 tcExtendTopTyVarScope kind tyvar_names $ \ _ result_kind ->
70 tcHsTypeKind rhs `thenTc` \ (rhs_kind, _) ->
71 unifyKind result_kind rhs_kind
73 kcTyDecl (TyData _ context tycon_name tyvar_names con_decls _ _ src_loc)
74 = tcLookupTy tycon_name `thenNF_Tc` \ (kind, _, _) ->
75 tcExtendTopTyVarScope kind tyvar_names $ \ result_kind _ ->
76 tcContext context `thenTc_`
77 mapTc kcConDecl con_decls `thenTc_`
80 kcConDecl (ConDecl _ ex_tvs ex_ctxt details loc)
82 tcExtendTyVarScope ex_tvs ( \ tyvars ->
83 tcContext ex_ctxt `thenTc_`
84 kc_con details `thenTc_`
88 kc_con (VanillaCon btys) = mapTc kc_bty btys `thenTc_` returnTc ()
89 kc_con (InfixCon bty1 bty2) = mapTc kc_bty [bty1,bty2] `thenTc_` returnTc ()
90 kc_con (NewCon ty _) = tcHsType ty `thenTc_` returnTc ()
91 kc_con (RecCon flds) = mapTc kc_field flds `thenTc_` returnTc ()
93 kc_bty (Banged ty) = tcHsType ty
94 kc_bty (Unbanged ty) = tcHsType ty
95 kc_bty (Unpacked ty) = tcHsType ty
97 kc_field (_, bty) = kc_bty bty
101 %************************************************************************
103 \subsection{Type checking}
105 %************************************************************************
108 tcTyDecl :: RecFlag -> FiniteMap Name ArgVrcs -> RenamedTyClDecl -> TcM s TyCon
110 tcTyDecl is_rec rec_vrcs (TySynonym tycon_name tyvar_names rhs src_loc)
111 = tcLookupTy tycon_name `thenNF_Tc` \ (tycon_kind, Just arity, _) ->
112 tcExtendTopTyVarScope tycon_kind tyvar_names $ \ tyvars _ ->
113 tcHsTopType rhs `thenTc` \ rhs_ty ->
115 -- Construct the tycon
116 argvrcs = lookupWithDefaultFM rec_vrcs (pprPanic "tcTyDecl: argvrcs:" $ ppr tycon_name)
118 tycon = mkSynTyCon tycon_name tycon_kind arity tyvars rhs_ty argvrcs
123 tcTyDecl is_rec rec_vrcs (TyData data_or_new context tycon_name tyvar_names con_decls derivings pragmas src_loc)
124 = -- Lookup the pieces
125 tcLookupTy tycon_name `thenNF_Tc` \ (tycon_kind, _, ATyCon rec_tycon) ->
126 tcExtendTopTyVarScope tycon_kind tyvar_names $ \ tyvars _ ->
128 -- Typecheck the pieces
129 tcContext context `thenTc` \ ctxt ->
130 mapTc (tcConDecl rec_tycon tyvars ctxt) con_decls `thenTc` \ data_cons ->
131 tc_derivs derivings `thenTc` \ derived_classes ->
134 -- Construct the tycon
135 real_data_or_new = case data_or_new of
137 DataType | all isNullaryDataCon data_cons -> EnumType
138 | otherwise -> DataType
140 argvrcs = lookupWithDefaultFM rec_vrcs (pprPanic "tcTyDecl: argvrcs:" $ ppr tycon_name)
143 tycon = mkAlgTyCon tycon_name tycon_kind tyvars ctxt argvrcs
146 Nothing -- Not a dictionary
147 real_data_or_new is_rec
151 tc_derivs Nothing = returnTc []
152 tc_derivs (Just ds) = mapTc tc_deriv ds
154 tc_deriv name = tcLookupTy name `thenTc` \ (_, _, AClass clas) ->
159 %************************************************************************
161 \subsection{Type check constructors}
163 %************************************************************************
166 tcConDecl :: TyCon -> [TyVar] -> ThetaType -> RenamedConDecl -> TcM s DataCon
168 tcConDecl tycon tyvars ctxt (ConDecl name ex_tvs ex_ctxt details src_loc)
169 = tcAddSrcLoc src_loc $
170 tcExtendTyVarScope ex_tvs $ \ ex_tyvars ->
171 tcContext ex_ctxt `thenTc` \ ex_theta ->
172 tc_con_decl_help tycon tyvars ctxt name ex_tyvars ex_theta details
174 tc_con_decl_help tycon tyvars ctxt name ex_tyvars ex_theta details
176 VanillaCon btys -> tc_datacon btys
177 InfixCon bty1 bty2 -> tc_datacon [bty1,bty2]
178 NewCon ty mb_f -> tc_newcon ty mb_f
179 RecCon fields -> tc_rec_con fields
183 arg_stricts = map get_strictness btys
184 tys = map get_pty btys
186 mapTc tcHsTopType tys `thenTc` \ arg_tys ->
187 mk_data_con arg_stricts arg_tys []
190 = tcHsTopBoxedType ty `thenTc` \ arg_ty ->
191 -- can't allow an unboxed type here, because we're effectively
192 -- going to remove the constructor while coercing it to a boxed type.
197 Just f -> [mkFieldLabel (getName f) arg_ty (head allFieldLabelTags)]
199 mk_data_con [NotMarkedStrict] [arg_ty] field_label
202 = checkTc (null ex_tyvars) (exRecConErr name) `thenTc_`
203 mapTc tc_field fields `thenTc` \ field_label_infos_s ->
205 field_label_infos = concat field_label_infos_s
206 arg_stricts = [strict | (_, _, strict) <- field_label_infos]
207 arg_tys = [ty | (_, ty, _) <- field_label_infos]
209 field_labels = [ mkFieldLabel (getName name) ty tag
210 | ((name, ty, _), tag) <- field_label_infos `zip` allFieldLabelTags ]
212 mk_data_con arg_stricts arg_tys field_labels
214 tc_field (field_label_names, bty)
215 = tcHsTopType (get_pty bty) `thenTc` \ field_ty ->
216 returnTc [(name, field_ty, get_strictness bty) | name <- field_label_names]
218 mk_data_con arg_stricts arg_tys fields
219 = -- Now we've checked all the field types we must
220 -- zonk the existential tyvars to finish the kind
221 -- inference on their kinds, and commit them to being
222 -- immutable type variables. (The top-level tyvars are
223 -- already fixed, by the preceding kind-inference pass.)
224 mapNF_Tc zonkTcTyVarToTyVar ex_tyvars `thenNF_Tc` \ ex_tyvars' ->
225 zonkTcThetaType ex_theta `thenNF_Tc` \ ex_theta' ->
227 data_con = mkDataCon name arg_stricts fields
228 tyvars (thinContext arg_tys ctxt)
232 data_con_id = mkDataConId data_con
236 -- The context for a data constructor should be limited to
237 -- the type variables mentioned in the arg_tys
238 thinContext arg_tys ctxt
239 = filter in_arg_tys ctxt
241 arg_tyvars = tyVarsOfTypes arg_tys
242 in_arg_tys (clas,tys) = not $ isEmptyVarSet $
243 tyVarsOfTypes tys `intersectVarSet` arg_tyvars
245 get_strictness (Banged _) = MarkedStrict
246 get_strictness (Unbanged _) = NotMarkedStrict
247 get_strictness (Unpacked _) = MarkedUnboxed bot bot
248 where bot = error "get_strictness"
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 = [ CoreMonoBind data_id (getUnfoldingTemplate (getIdUnfolding data_id))
280 | data_id <- data_ids, isLocallyDefined data_id
283 returnTc (data_ids, andMonoBindList binds)
285 data_cons = tyConDataCons tycon
286 fields = [ (con, field) | con <- data_cons,
287 field <- dataConFieldLabels con
290 -- groups is list of fields that share a common name
291 groups = equivClasses cmp_name fields
292 cmp_name (_, field1) (_, field2)
293 = fieldLabelName field1 `compare` fieldLabelName field2
297 mkRecordSelector tycon fields@((first_con, first_field_label) : other_fields)
298 -- These fields all have the same name, but are from
299 -- different constructors in the data type
300 -- Check that all the fields in the group have the same type
301 -- This check assumes that all the constructors of a given
302 -- data type use the same type variables
303 = checkTc (all (== field_ty) other_tys)
304 (fieldTypeMisMatch field_name) `thenTc_`
307 field_ty = fieldLabelType first_field_label
308 field_name = fieldLabelName first_field_label
309 other_tys = [fieldLabelType fl | (_, fl) <- other_fields]
310 (tyvars, _, _, _, _, _) = dataConSig first_con
311 data_ty = mkTyConApp tycon (mkTyVarTys tyvars)
312 -- tyvars of first_con may be free in field_ty
313 -- Now build the selector
316 selector_ty = mkForAllTys tyvars $
322 | isNewTyCon tycon = mkNewTySelId first_field_label selector_ty
323 | otherwise = mkRecordSelId first_field_label selector_ty
330 fieldTypeMisMatch field_name
331 = sep [ptext SLIT("Declared types differ for field"), quotes (ppr field_name)]
334 = ptext SLIT("Can't combine named fields with locally-quantified type variables")
336 (ptext SLIT("In the declaration of data constructor") <+> ppr name)