\begin{code}
module TcTyDecls (
- tcTyDecl,
- tcConDecl,
- mkDataBinds
+ tcTyDecl1, kcConDetails, mkNewTyConRep
) where
#include "HsVersions.h"
-import HsSyn ( MonoBinds(..),
- TyDecl(..), ConDecl(..), ConDetails(..), BangType(..),
- andMonoBindList
+import HsSyn ( TyClDecl(..), ConDecl(..), ConDetails(..),
+ getBangType, getBangStrictness, conDetailsTys
)
-import RnHsSyn ( RenamedTyDecl, RenamedConDecl )
-import TcHsSyn ( TcMonoBinds )
-import BasicTypes ( RecFlag(..), NewOrData(..), StrictnessMark(..) )
-
-import Inst ( InstOrigin(..) )
-import TcMonoType ( tcHsTypeKind, tcHsType, tcContext )
-import TcEnv ( TcIdOcc(..),
- tcLookupTyCon, tcLookupClass,
- tcLookupTyVarBndrs
+import RnHsSyn ( RenamedTyClDecl, RenamedConDecl, RenamedContext )
+import BasicTypes ( NewOrData(..), RecFlag, isRec )
+
+import TcMonoType ( tcHsRecType, tcHsTyVars, tcRecTheta,
+ kcHsContext, kcHsSigType, kcHsLiftedSigType
+ )
+import TcEnv ( tcExtendTyVarEnv,
+ tcLookupTyCon, tcLookupRecId,
+ TyThingDetails(..), RecTcEnv
)
import TcMonad
-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 DataCon ( DataCon, mkDataCon, dataConFieldLabels, dataConRepType )
+import MkId ( mkDataConId, mkDataConWrapId, mkRecordSelId )
import FieldLabel
-import Var ( Id, TyVar )
-import Name ( isLocallyDefined, OccName(..), NamedThing(..) )
+import Var ( TyVar )
+import Name ( Name, NamedThing(..) )
import Outputable
-import TyCon ( TyCon, mkSynTyCon, mkAlgTyCon, isAlgTyCon,
- isSynTyCon, tyConDataCons
- )
-import Type ( typeKind, getTyVar, tyVarsOfTypes,
- mkTyConApp, mkTyVarTys, mkForAllTys, mkFunTy,
- mkTyVarTy,
- mkArrowKind, mkArrowKinds, boxedTypeKind,
- isUnboxedType, Type, ThetaType
+import TyCon ( TyCon, isNewTyCon, tyConTyVars )
+import Type ( tyVarsOfTypes, tyVarsOfPred, splitFunTy, applyTys,
+ mkTyConApp, mkTyVarTys, mkForAllTys,
+ splitAlgTyConApp_maybe, Type, ThetaType
)
-import Var ( tyVarKind )
+import TysWiredIn ( unitTy )
import VarSet ( intersectVarSet, isEmptyVarSet )
-import Util ( equivClasses, panic, assertPanic )
-\end{code}
-
-\begin{code}
-tcTyDecl :: RecFlag -> RenamedTyDecl -> TcM s TyCon
+import PrelNames ( unpackCStringName, unpackCStringUtf8Name )
+import ListSetOps ( equivClasses )
\end{code}
-Type synonym decls
-~~~~~~~~~~~~~~~~~~
+%************************************************************************
+%* *
+\subsection{Type checking}
+%* *
+%************************************************************************
\begin{code}
-tcTyDecl is_rec (TySynonym tycon_name tyvar_names rhs src_loc)
- = tcAddSrcLoc src_loc $
- tcAddErrCtxt (tySynCtxt tycon_name) $
-
- -- Look up the pieces
- tcLookupTyCon tycon_name `thenTc` \ (tycon_kind, _, rec_tycon) ->
- tcLookupTyVarBndrs tyvar_names `thenNF_Tc` \ (tyvar_kinds, rec_tyvars) ->
-
- -- Look at the rhs
- tcHsTypeKind rhs `thenTc` \ (rhs_kind, rhs_ty) ->
-
- -- Unify tycon kind with (k1->...->kn->rhs)
- unifyKind tycon_kind (mkArrowKinds tyvar_kinds rhs_kind) `thenTc_`
+tcTyDecl1 :: RecFlag -> RecTcEnv -> RenamedTyClDecl -> TcM (Name, TyThingDetails)
+tcTyDecl1 is_rec unf_env (TySynonym {tcdName = tycon_name, tcdSynRhs = rhs})
+ = tcLookupTyCon tycon_name `thenNF_Tc` \ tycon ->
+ tcExtendTyVarEnv (tyConTyVars tycon) $
+ tcHsRecType is_rec rhs `thenTc` \ rhs_ty ->
+ -- Note tcHsRecType not tcHsRecSigType; we allow type synonyms
+ -- that aren't types; e.g. type List = []
+ --
+ -- If the RHS mentions tyvars that aren't in scope, we'll
+ -- quantify over them:
+ -- e.g. type T = a->a
+ -- will become type T = forall a. a->a
+ --
+ -- With gla-exts that's right, but for H98 we should complain.
+ -- We can now do that here without falling into
+ -- a black hole, we still do it in rnDecl (TySynonym case)
+
+ returnTc (tycon_name, SynTyDetails rhs_ty)
+
+tcTyDecl1 is_rec unf_env (TyData {tcdND = new_or_data, tcdCtxt = context,
+ tcdName = tycon_name, tcdCons = con_decls})
+ = tcLookupTyCon tycon_name `thenNF_Tc` \ tycon ->
let
- -- Construct the tycon
- kind = mkArrowKinds (map tyVarKind rec_tyvars) (typeKind rhs_ty)
- tycon = mkSynTyCon (getName tycon_name)
- kind
- (length tyvar_names)
- rec_tyvars
- rhs_ty
+ tyvars = tyConTyVars tycon
in
- returnTc tycon
-\end{code}
+ tcExtendTyVarEnv tyvars $
-Algebraic data and newtype decls
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ -- Typecheck the pieces
+ tcRecTheta is_rec context `thenTc` \ ctxt ->
+ mapTc (tcConDecl is_rec new_or_data tycon tyvars ctxt) con_decls `thenTc` \ data_cons ->
+ tcRecordSelectors is_rec unf_env tycon data_cons `thenTc` \ sel_ids ->
+ returnTc (tycon_name, DataTyDetails ctxt data_cons sel_ids)
+\end{code}
\begin{code}
-tcTyDecl is_rec (TyData data_or_new context tycon_name tyvar_names con_decls derivings pragmas src_loc)
- = tcAddSrcLoc src_loc $
- let ctxt = case data_or_new of
- NewType -> tyNewCtxt tycon_name
- DataType -> tyDataCtxt tycon_name
- in
- tcAddErrCtxt ctxt $
+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
- -- Lookup the pieces
- tcLookupTyCon tycon_name `thenTc` \ (tycon_kind, _, rec_tycon) ->
- tcLookupTyVarBndrs tyvar_names `thenNF_Tc` \ (tyvar_kinds, rec_tyvars) ->
- tc_derivs derivings `thenTc` \ derived_classes ->
-
- -- Typecheck the context
- tcContext context `thenTc` \ ctxt ->
-
- -- Unify tycon kind with (k1->...->kn->Type)
- unifyKind tycon_kind (mkArrowKinds tyvar_kinds boxedTypeKind) `thenTc_`
-
- -- Walk the condecls
- mapTc (tcConDecl rec_tycon rec_tyvars ctxt) con_decls
- `thenTc` \ data_cons ->
- let
- -- Construct the tycon
- real_data_or_new = case data_or_new of
- NewType -> NewType
- DataType -> if all isNullaryDataCon data_cons then
- EnumType
- else
- DataType
-
- kind = foldr (mkArrowKind . tyVarKind) boxedTypeKind rec_tyvars
- tycon = mkAlgTyCon (getName tycon_name)
- kind
- rec_tyvars
- ctxt
- data_cons
- derived_classes
- Nothing -- Not a dictionary
- real_data_or_new
- is_rec
- in
- returnTc tycon
-
-tc_derivs Nothing = returnTc []
-tc_derivs (Just ds) = mapTc tc_deriv ds
-
-tc_deriv name
- = tcLookupClass name `thenTc` \ (_, clas) ->
- returnTc clas
+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}
-Generating constructor/selector bindings for data declarations
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-\begin{code}
-mkDataBinds :: [TyCon] -> TcM s ([Id], TcMonoBinds s)
-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 (RealId 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}
+%************************************************************************
+%* *
+\subsection{Kind and type check constructors}
+%* *
+%************************************************************************
\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
+kcConDetails :: NewOrData -> RenamedContext -> ConDetails Name -> TcM ()
+kcConDetails new_or_data ex_ctxt details
+ = kcHsContext ex_ctxt `thenTc_`
+ mapTc_ kc_sig_type (conDetailsTys details)
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}
-
-Constructors
-~~~~~~~~~~~~
-\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 $
- tcLookupTyVarBndrs ex_tvs `thenNF_Tc` \ (kinds, ex_tyvars) ->
- tcContext ex_ctxt `thenTc` \ ex_theta ->
- tc_con_help tycon tyvars ctxt name ex_tyvars ex_theta details
-
-tc_con_help tycon tyvars ctxt name ex_tyvars ex_theta (VanillaCon btys)
- = tc_datacon_help tycon tyvars ctxt name ex_tyvars ex_theta btys
-
-tc_con_help tycon tyvars ctxt name ex_tyvars ex_theta (InfixCon bty1 bty2)
- = tc_datacon_help tycon tyvars ctxt name ex_tyvars ex_theta [bty1,bty2]
-
-tc_con_help tycon tyvars ctxt name ex_tyvars ex_theta (NewCon ty)
- = tcHsType 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.
- checkTc (not (isUnboxedType arg_ty)) (newTypeUnboxedField ty) `thenTc_`
- let
- data_con = mkDataCon (getName name)
- [NotMarkedStrict]
- [{- No labelled fields -}]
- tyvars
- ctxt
- ex_tyvars ex_theta
- [arg_ty]
- tycon data_con_id
- data_con_id = mkDataConId data_con
- in
- returnTc data_con
-
-tc_con_help tycon tyvars ctxt name ex_tyvars ex_theta (RecCon fields)
- = checkTc (null ex_tyvars) (exRecConErr name) `thenTc_`
- mapTc tcField 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 ]
-
- data_con = mkDataCon (getName name)
- arg_stricts
- field_labels
- tyvars
- (thinContext arg_tys ctxt)
+ kc_sig_type = case new_or_data of
+ DataType -> kcHsSigType
+ NewType -> kcHsLiftedSigType
+ -- Can't allow an unlifted type here, because we're effectively
+ -- going to remove the constructor while coercing it to a lifted type.
+
+
+tcConDecl :: RecFlag -> NewOrData -> TyCon -> [TyVar] -> ThetaType -> RenamedConDecl -> TcM DataCon
+
+tcConDecl is_rec new_or_data tycon tyvars ctxt (ConDecl name wkr_name ex_tvs ex_ctxt details src_loc)
+ = tcAddSrcLoc src_loc $
+ tcHsTyVars ex_tvs (kcConDetails new_or_data ex_ctxt details) $ \ ex_tyvars ->
+ tcRecTheta is_rec ex_ctxt `thenTc` \ ex_theta ->
+ case details of
+ VanillaCon btys -> tc_datacon ex_tyvars ex_theta btys
+ InfixCon bty1 bty2 -> tc_datacon ex_tyvars ex_theta [bty1,bty2]
+ RecCon fields -> tc_rec_con ex_tyvars ex_theta fields
+ where
+ tc_datacon ex_tyvars ex_theta btys
+ = let
+ arg_stricts = map getBangStrictness btys
+ tys = map getBangType btys
+ in
+ mapTc (tcHsRecType is_rec) tys `thenTc` \ arg_tys ->
+ mk_data_con ex_tyvars ex_theta arg_stricts arg_tys []
+
+ tc_rec_con ex_tyvars ex_theta fields
+ = checkTc (null ex_tyvars) (exRecConErr name) `thenTc_`
+ mapTc tc_field (fields `zip` allFieldLabelTags) `thenTc` \ field_labels_s ->
+ let
+ field_labels = concat field_labels_s
+ arg_stricts = [str | (ns, bty) <- fields,
+ let str = getBangStrictness bty,
+ n <- ns -- One for each. E.g x,y,z :: !Int
+ ]
+ in
+ mk_data_con ex_tyvars ex_theta arg_stricts
+ (map fieldLabelType field_labels) field_labels
+
+ tc_field ((field_label_names, bty), tag)
+ = tcHsRecType is_rec (getBangType bty) `thenTc` \ field_ty ->
+ returnTc [mkFieldLabel (getName name) tycon field_ty tag | name <- field_label_names]
+
+ mk_data_con ex_tyvars ex_theta arg_stricts arg_tys fields
+ = let
+ data_con = mkDataCon name arg_stricts fields
+ tyvars (thinContext arg_tys ctxt)
ex_tyvars ex_theta
arg_tys
- tycon data_con_id
- data_con_id = mkDataConId data_con
- in
- returnTc data_con
+ tycon data_con_id data_con_wrap_id
-tcField (field_label_names, bty)
- = tcHsType (get_pty bty) `thenTc` \ field_ty ->
- returnTc [(name, field_ty, get_strictness bty) | name <- field_label_names]
-
-tc_datacon_help tycon tyvars ctxt name ex_tyvars ex_theta btys
- = let
- arg_stricts = map get_strictness btys
- tys = map get_pty btys
- in
- mapTc tcHsType tys `thenTc` \ arg_tys ->
- let
- data_con = mkDataCon (getName name)
- arg_stricts
- [{- No field labels -}]
- tyvars
- (thinContext arg_tys ctxt)
- ex_tyvars ex_theta
- arg_tys
- tycon data_con_id
- data_con_id = mkDataConId data_con
- in
- returnTc data_con
+ 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
= 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
+ in_arg_tys pred = not $ isEmptyVarSet $
+ tyVarsOfPred pred `intersectVarSet` arg_tyvars
\end{code}
+%************************************************************************
+%* *
+\subsection{Record selectors}
+%* *
+%************************************************************************
-Errors and contexts
-~~~~~~~~~~~~~~~~~~~
\begin{code}
-tySynCtxt tycon_name
- = hsep [ptext SLIT("In the type declaration for"), quotes (ppr tycon_name)]
+tcRecordSelectors is_rec unf_env tycon data_cons
+ -- Omit the check that the fields have consistent types if
+ -- the group is recursive; TcTyClsDecls.tcGroup will repeat
+ -- with NonRecursive once we have tied the knot
+ | isRec is_rec = returnTc sel_ids
+ | otherwise = mapTc check groups `thenTc_`
+ returnTc sel_ids
+ where
+ fields = [ 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
+
+ sel_ids = [ mkRecordSelId tycon field unpack_id unpackUtf8_id
+ | (field : _) <- groups ]
+
+ check fields@(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
+ -- NB: 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)
+ where
+ field_ty = fieldLabelType first_field_label
+ field_name = fieldLabelName first_field_label
+ other_tys = map fieldLabelType other_fields
+
+ unpack_id = tcLookupRecId unf_env unpackCStringName
+ unpackUtf8_id = tcLookupRecId unf_env unpackCStringUtf8Name
+\end{code}
-tyDataCtxt tycon_name
- = hsep [ptext SLIT("In the data declaration for"), quotes (ppr tycon_name)]
-tyNewCtxt tycon_name
- = hsep [ptext SLIT("In the newtype declaration for"), quotes (ppr tycon_name)]
-fieldTypeMisMatch field_name
- = sep [ptext SLIT("Declared types differ for field"), quotes (ppr field_name)]
+%************************************************************************
+%* *
+\subsection{Errors and contexts}
+%* *
+%************************************************************************
-newTypeUnboxedField ty
- = sep [ptext SLIT("Newtype constructor field has an unboxed type:"),
- quotes (ppr ty)]
+
+\begin{code}
+fieldTypeMisMatch field_name
+ = sep [ptext SLIT("Different constructors give different types for field"), quotes (ppr field_name)]
exRecConErr name
= ptext SLIT("Can't combine named fields with locally-quantified type variables")
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