%
-% (c) The GRASP/AQUA Project, Glasgow University, 1992-1995
+% (c) The AQUA Project, Glasgow University, 1996-1998
%
-\section[TcTyDecls]{Typecheck algebraic datatypes and type synonyms}
+\section[TcTyDecls]{Typecheck type declarations}
\begin{code}
-#include "HsVersions.h"
+module TcTyDecls (
+ tcTyDecl, kcTyDecl,
+ tcConDecl,
+ mkImplicitDataBinds, mkNewTyConRep
+ ) where
-module TcTyDecls ( tcTyDecls ) where
+#include "HsVersions.h"
-import TcMonad -- typechecking monad machinery
-import AbsSyn -- the stuff being typechecked
+import HsSyn ( MonoBinds(..),
+ TyClDecl(..), ConDecl(..), ConDetails(..), BangType(..),
+ andMonoBindList
+ )
+import RnHsSyn ( RenamedTyClDecl, RenamedConDecl )
+import TcHsSyn ( TcMonoBinds, idsToMonoBinds )
+import BasicTypes ( RecFlag(..), NewOrData(..) )
-import AbsUniType ( applyTyCon, mkDataTyCon, mkSynonymTyCon,
- getUniDataTyCon, isUnboxedDataType,
- isTyVarTemplateTy, cmpUniTypeMaybeList,
- pprMaybeTy
+import TcMonoType ( tcExtendTopTyVarScope, tcExtendTyVarScope,
+ tcHsTypeKind, kcHsType, tcHsTopType, tcHsTopBoxedType,
+ tcContext, tcHsTopTypeKind
+ )
+import TcType ( zonkTcTyVarToTyVar, zonkTcClassConstraints )
+import TcEnv ( tcLookupTy, tcLookupValueByKey, TcTyThing(..) )
+import TcMonad
+import TcUnify ( unifyKind )
+
+import Class ( Class )
+import DataCon ( DataCon, mkDataCon, isNullaryDataCon,
+ dataConFieldLabels, dataConId, dataConWrapId,
+ markedStrict, notMarkedStrict, markedUnboxed, dataConRepType
)
-import CE ( lookupCE, CE(..) )
-import CmdLineOpts ( GlobalSwitch(..) )
-import E ( getE_TCE, getE_CE, plusGVE, nullGVE, GVE(..), E )
-import ErrUtils ( addShortErrLocLine )
-import Errors ( confusedNameErr, specDataNoSpecErr, specDataUnboxedErr )
-import FiniteMap ( FiniteMap, emptyFM, plusFM, singletonFM )
-import IdInfo ( SpecEnv, mkSpecEnv, SpecInfo(..) )
-import Pretty
-import SpecTyFuns ( specialiseConstrTys )
-import TCE -- ( nullTCE, unitTCE, lookupTCE, plusTCE, TCE(..), UniqFM )
-import TVE ( mkTVE, TVE(..) )
-import TcConDecls ( tcConDecls )
-import TcMonoType ( tcMonoType )
-import TcPragmas ( tcDataPragmas, tcTypePragmas )
-import Util
+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}
-We consult the @CE@/@TCE@ arguments {\em only} to build knots!
-
-The resulting @TCE@ has info about the type constructors in it; the
-@GVE@ has info about their data constructors.
+%************************************************************************
+%* *
+\subsection{Kind checking}
+%* *
+%************************************************************************
\begin{code}
-tcTyDecls :: E
- -> (Name -> Bool) -- given Name, is it an abstract synonym?
- -> (Name -> [RenamedDataTypeSig]) -- given Name, get specialisation pragmas
- -> [RenamedTyDecl]
- -> Baby_TcM (TCE, GVE,
- FiniteMap TyCon [(Bool, [Maybe UniType])])
- -- specialisations:
- -- True => imported data types i.e. from interface file
- -- False => local data types i.e. requsted by source pragmas
-
-tcTyDecls e _ _ [] = returnB_Tc (nullTCE, nullGVE, emptyFM)
-
-tcTyDecls e is_abs_syn get_spec_sigs (tyd: tyds)
- = tc_decl tyd `thenB_Tc` \ (tce1, gve1, specs1) ->
- tcTyDecls e is_abs_syn get_spec_sigs tyds
- `thenB_Tc` \ (tce2, gve2, specs2) ->
- let
- tce3 = tce1 `plusTCE` tce2
- gve3 = gve1 `plusGVE` gve2
- specs3 = specs1 `plusFM` specs2
- in
- returnB_Tc (tce3, gve3, specs3)
+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
- rec_ce = getE_CE e
- rec_tce = getE_TCE e
+ 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 ()
- -- continued...
+ kc_bty (Banged ty) = kcHsType ty
+ kc_bty (Unbanged ty) = kcHsType ty
+ kc_bty (Unpacked ty) = kcHsType ty
+
+ kc_field (_, bty) = kc_bty bty
\end{code}
-We don't need to substitute here, because the @TCE@s
-(which are at the top level) cannot contain free type variables.
-Gather relevant info:
-\begin{code}
- tc_decl (TyData context name@(PreludeTyCon uniq full_name arity True{-"data"-})
- tyvars con_decls derivings pragmas src_loc)
- -- ToDo: context
- = tc_data_decl uniq name full_name arity tyvars con_decls
- derivings pragmas src_loc
-
- tc_decl (TyData context name@(OtherTyCon uniq full_name arity True{-"data"-} _)
- tyvars con_decls derivings pragmas src_loc)
- -- ToDo: context
- = tc_data_decl uniq name full_name arity tyvars con_decls
- derivings pragmas src_loc
-
- tc_decl (TyData _ bad_name _ _ _ _ src_loc)
- = failB_Tc (confusedNameErr "Bad name on a datatype constructor (a Prelude name?)"
- bad_name src_loc)
-
- tc_decl (TySynonym name@(PreludeTyCon uniq full_name arity False{-"type"-})
- tyvars mono_ty pragmas src_loc)
- = tc_syn_decl uniq name full_name arity tyvars mono_ty pragmas src_loc
-
- tc_decl (TySynonym name@(OtherTyCon uniq full_name arity False{-"type"-} _)
- tyvars mono_ty pragmas src_loc)
- = tc_syn_decl uniq name full_name arity tyvars mono_ty pragmas src_loc
-
- tc_decl (TySynonym bad_name _ _ _ src_loc)
- = failB_Tc (confusedNameErr "Bad name on a type-synonym constructor (a Prelude name?)"
- bad_name src_loc)
-\end{code}
+%************************************************************************
+%* *
+\subsection{Type checking}
+%* *
+%************************************************************************
-Real work for @data@ declarations:
\begin{code}
- tc_data_decl uniq name full_name arity tyvars con_decls derivings pragmas src_loc
- = addSrcLocB_Tc src_loc (
- let
- (tve, new_tyvars, _) = mkTVE tyvars
- rec_tycon = lookupTCE rec_tce name
- -- We know the lookup will succeed, because we are just
- -- about to put it in the outgoing TCE!
-
- spec_sigs = get_spec_sigs name
- in
- tcSpecDataSigs rec_tce spec_sigs [] `thenB_Tc` \ user_spec_infos ->
+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
+ 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_name, ASynTyCon tycon arity)
- recoverIgnoreErrorsB_Tc ([], []) (
- tcDataPragmas rec_tce tve rec_tycon new_tyvars pragmas
- ) `thenB_Tc` \ (pragma_con_decls, pragma_spec_infos) ->
- let
- (condecls_to_use, ignore_condecl_errors_if_pragma)
- = if null pragma_con_decls then
- (con_decls, id)
- else
- if null con_decls
- then (pragma_con_decls, recoverIgnoreErrorsB_Tc nullGVE)
- else panic "tcTyDecls:data: user and pragma condecls!"
-
- (imported_specs, specinfos_to_use)
- = if null pragma_spec_infos then
- (False, user_spec_infos)
- else
- if null user_spec_infos
- then (True, pragma_spec_infos)
- else panic "tcTyDecls:data: user and pragma specinfos!"
-
- specenv_to_use = mkSpecEnv specinfos_to_use
- in
- ignore_condecl_errors_if_pragma
- (tcConDecls rec_tce tve rec_tycon new_tyvars specenv_to_use condecls_to_use)
- `thenB_Tc` \ gve ->
- let
- condecls = map snd gve
- derived_classes = map (lookupCE rec_ce) derivings
+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 _ ->
- new_tycon
- = mkDataTyCon uniq
- full_name arity new_tyvars condecls
- derived_classes
- (null pragma_con_decls)
- -- if constrs are from pragma we are *abstract*
+ -- 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 ->
- spec_list
- = [(imported_specs, maybe_tys) | (SpecInfo maybe_tys _ _) <- specinfos_to_use]
+ let
+ -- Construct the tycon
+ 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_name, ADataTyCon tycon)
+ where
+ tc_derivs Nothing = returnTc []
+ tc_derivs (Just ds) = mapTc tc_deriv ds
- spec_map
- = if null spec_list then
- emptyFM
- else
- singletonFM rec_tycon spec_list
- in
- returnB_Tc (unitTCE uniq new_tycon, gve, spec_map)
- -- It's OK to return pragma condecls in gve, even
- -- though some of those names should be "invisible",
- -- because the *renamer* is supposed to have dealt with
- -- naming/scope issues already.
- )
+ tc_deriv name = tcLookupTy name `thenTc` \ (_, AClass clas _) ->
+ returnTc clas
\end{code}
-Real work for @type@ (synonym) declarations:
\begin{code}
- tc_syn_decl uniq name full_name arity tyvars mono_ty pragmas src_loc
- = addSrcLocB_Tc src_loc (
+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
- let (tve, new_tyvars, _) = mkTVE tyvars
- in
- tcMonoType rec_ce rec_tce tve mono_ty `thenB_Tc` \ expansion ->
- let
- -- abstractness info either comes from the interface pragmas
- -- (tcTypePragmas) or from a user-pragma in this module
- -- (is_abs_syn)
- abstract = tcTypePragmas pragmas
- || is_abs_syn name
-
- new_tycon = mkSynonymTyCon uniq full_name
- arity new_tyvars expansion (not abstract)
- in
- returnB_Tc (unitTCE uniq new_tycon, nullGVE, emptyFM)
- )
+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}
+
%************************************************************************
%* *
-\subsection{Specialisation Signatures for Data Type declarations}
+\subsection{Type check constructors}
%* *
%************************************************************************
-@tcSpecDataSigs@ checks data type specialisation signatures for
-validity, and returns the list of specialisation requests.
-
\begin{code}
-tcSpecDataSigs :: TCE
- -> [RenamedDataTypeSig]
- -> [(RenamedDataTypeSig,SpecInfo)]
- -> Baby_TcM [SpecInfo]
-
-tcSpecDataSigs tce (s:ss) accum
- = tc_sig s `thenB_Tc` \ info ->
- tcSpecDataSigs tce ss ((s,info):accum)
+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
+ 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_sig (SpecDataSig n ty src_loc)
- = addSrcLocB_Tc src_loc (
- let
- ty_names = extractMonoTyNames (==) ty
- (tve,_,_) = mkTVE ty_names
- fake_CE = panic "tcSpecDataSigs:CE"
+ 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
- -- Typecheck specialising type (includes arity check)
- tcMonoType fake_CE tce tve ty `thenB_Tc` \ tau_ty ->
+ 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
- (_,ty_args,_) = getUniDataTyCon tau_ty
- is_unboxed_or_tyvar ty = isUnboxedDataType ty || isTyVarTemplateTy ty
+ 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
- -- Check at least one unboxed type in specialisation
- checkB_Tc (not (any isUnboxedDataType ty_args))
- (specDataNoSpecErr n ty_args src_loc) `thenB_Tc_`
+ returnNF_Tc data_con
- -- Check all types are unboxed or tyvars
- -- (specific boxed types are redundant)
- checkB_Tc (not (all is_unboxed_or_tyvar ty_args))
- (specDataUnboxedErr n ty_args src_loc) `thenB_Tc_`
+-- 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}
- let
- maybe_tys = specialiseConstrTys ty_args
- in
- returnB_Tc (SpecInfo maybe_tys 0 (panic "SpecData:SpecInfo:SpecId"))
- )
-
-tcSpecDataSigs tce [] accum
- = -- Remove any duplicates from accumulated specinfos
- getSwitchCheckerB_Tc `thenB_Tc` \ sw_chkr ->
-
- (if sw_chkr SpecialiseTrace && not (null duplicates) then
- pprTrace "Duplicate SPECIALIZE data pragmas:\n"
- (ppAboves (map specmsg sep_dups))
- else id)(
-
- (if sw_chkr SpecialiseTrace && not (null spec_infos) then
- pprTrace "Specialising "
- (ppHang (ppCat [ppr PprDebug name, ppStr "at types:"])
- 4 (ppAboves (map pp_spec spec_infos)))
-
- else id) (
-
- returnB_Tc (spec_infos)
- ))
+
+
+%************************************************************************
+%* *
+\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
+ 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
- spec_infos = map (snd . head) equiv
+ data_cons = tyConDataConsIfAvailable tycon
+ -- Abstract types mean we don't bring the
+ -- data cons into scope, which should be fine
+
+ data_con_wrapper_ids = map dataConWrapId data_cons
- equiv = equivClasses cmp_info accum
- duplicates = filter (not . singleton) equiv
+ 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}
- cmp_info (_, SpecInfo tys1 _ _) (_, SpecInfo tys2 _ _)
- = cmpUniTypeMaybeList tys1 tys2
+\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}
- singleton [_] = True
- singleton _ = False
- sep_dups = tail (concat (map ((:) Nothing . map Just) duplicates))
- specmsg (Just (SpecDataSig _ ty locn, _))
- = addShortErrLocLine locn ( \ sty -> ppr sty ty ) PprDebug
- specmsg Nothing
- = ppStr "***"
+Errors and contexts
+~~~~~~~~~~~~~~~~~~~
+\begin{code}
+fieldTypeMisMatch field_name
+ = sep [ptext SLIT("Declared types differ for field"), quotes (ppr field_name)]
- ((SpecDataSig name _ _, _):_) = accum
- pp_spec (SpecInfo tys _ _) = ppInterleave ppNil [pprMaybeTy PprDebug ty | ty <- tys]
+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}
projects / ghc-hetmet.git / blobdiff