\section[TcTyDecls]{Typecheck type declarations}
\begin{code}
-module TcTyDecls (
- tcTyDecl1, kcConDetails, mkNewTyConRep
- ) where
+module TcTyDecls ( tcTyDecl, kcConDetails ) where
#include "HsVersions.h"
-import HsSyn ( TyClDecl(..), ConDecl(..), ConDetails(..), BangType(..),
- getBangType, conDetailsTys
+import HsSyn ( TyClDecl(..), ConDecl(..), ConDetails(..),
+ getBangType, getBangStrictness, conDetailsTys
)
import RnHsSyn ( RenamedTyClDecl, RenamedConDecl, RenamedContext )
-import BasicTypes ( NewOrData(..), RecFlag, isRec )
+import BasicTypes ( NewOrData(..) )
-import TcMonoType ( tcHsRecType, tcHsTyVars, tcRecClassContext,
- kcHsContext, kcHsSigType, kcHsBoxedSigType
+import TcMonoType ( tcHsTyVars, tcHsTheta, tcHsType,
+ kcHsContext, kcHsSigType, kcHsLiftedSigType
)
import TcEnv ( tcExtendTyVarEnv,
tcLookupTyCon, tcLookupRecId,
TyThingDetails(..), RecTcEnv
)
+import TcType ( tyVarsOfTypes, tyVarsOfPred, ThetaType )
import TcMonad
-import Class ( ClassContext )
-import DataCon ( DataCon, mkDataCon, dataConFieldLabels, markedStrict,
- notMarkedStrict, markedUnboxed, dataConRepType
- )
+import DataCon ( DataCon, mkDataCon, dataConFieldLabels )
+import FieldLabel ( fieldLabelName, fieldLabelType, allFieldLabelTags, mkFieldLabel )
import MkId ( mkDataConId, mkDataConWrapId, mkRecordSelId )
-import FieldLabel
import Var ( TyVar )
import Name ( Name, NamedThing(..) )
import Outputable
-import TyCon ( TyCon, isNewTyCon, tyConTyVars )
-import Type ( tyVarsOfTypes, splitFunTy, applyTys,
- mkTyConApp, mkTyVarTys, mkForAllTys,
- splitAlgTyConApp_maybe, Type
- )
-import TysWiredIn ( unitTy )
+import TyCon ( TyCon, DataConDetails(..), visibleDataCons,
+ tyConTyVars )
import VarSet ( intersectVarSet, isEmptyVarSet )
import PrelNames ( unpackCStringName, unpackCStringUtf8Name )
-import ListSetOps ( equivClasses )
+import List ( nubBy )
\end{code}
%************************************************************************
%************************************************************************
\begin{code}
-tcTyDecl1 :: RecFlag -> RecTcEnv -> RenamedTyClDecl -> TcM (Name, TyThingDetails)
-tcTyDecl1 is_rec unf_env (TySynonym tycon_name tyvar_names rhs src_loc)
+tcTyDecl :: RenamedTyClDecl -> TcM (Name, TyThingDetails)
+tcTyDecl (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)
-
+ tcHsType rhs `thenTc` \ rhs_ty ->
returnTc (tycon_name, SynTyDetails rhs_ty)
-tcTyDecl1 is_rec unf_env (TyData new_or_data context tycon_name _ con_decls _ derivings src_loc name1 name2)
+tcTyDecl (TyData {tcdND = new_or_data, tcdCtxt = context,
+ tcdName = tycon_name, tcdCons = con_decls})
= tcLookupTyCon tycon_name `thenNF_Tc` \ tycon ->
let
tyvars = tyConTyVars tycon
in
tcExtendTyVarEnv tyvars $
-
- -- Typecheck the pieces
- tcRecClassContext 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 ->
+ tcHsTheta context `thenTc` \ ctxt ->
+ tcConDecls new_or_data tycon tyvars ctxt con_decls `thenTc` \ data_cons ->
+ let
+ sel_ids = mkRecordSelectors tycon data_cons
+ in
returnTc (tycon_name, DataTyDetails ctxt data_cons sel_ids)
-\end{code}
-\begin{code}
-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
+tcTyDecl (ForeignType {tcdName = tycon_name})
+ = returnTc (tycon_name, ForeignTyDetails)
+
-mkNewTyConRep tc
- = mkForAllTys tvs (loop [] (mkTyConApp tc (mkTyVarTys tvs)))
+mkRecordSelectors tycon data_cons
+ = -- We'll check later that fields with the same name
+ -- from different constructors have the same type.
+ [ mkRecordSelId tycon field
+ | field <- nubBy eq_name fields ]
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
- }
+ fields = [ field | con <- visibleDataCons data_cons,
+ field <- dataConFieldLabels con ]
+ eq_name field1 field2 = fieldLabelName field1 == fieldLabelName field2
\end{code}
where
kc_sig_type = case new_or_data of
DataType -> kcHsSigType
- NewType -> kcHsBoxedSigType
- -- Can't allow an unboxed type here, because we're effectively
- -- going to remove the constructor while coercing it to a boxed type.
+ 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] -> ClassContext -> RenamedConDecl -> TcM DataCon
+tcConDecls :: NewOrData -> TyCon -> [TyVar] -> ThetaType
+ -> DataConDetails RenamedConDecl -> TcM (DataConDetails 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 ->
- tcRecClassContext 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
+tcConDecls new_or_data tycon tyvars ctxt con_decls
+ = case con_decls of
+ Unknown -> returnTc Unknown
+ HasCons n -> returnTc (HasCons n)
+ DataCons cs -> mapTc tc_con_decl cs `thenTc` \ data_cons ->
+ returnTc (DataCons data_cons)
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_wrap_id
-
- data_con_id = mkDataConId wkr_name data_con
- data_con_wrap_id = mkDataConWrapId data_con
- in
- returnNF_Tc data_con
+ tc_con_decl (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 ->
+ tcHsTheta 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
+ = mapTc tcHsType (map getBangType btys) `thenTc` \ arg_tys ->
+ mk_data_con ex_tyvars ex_theta (map getBangStrictness btys) 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)
+ = tcHsType (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_wrap_id
+
+ 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
-
-getBangStrictness (Banged _) = markedStrict
-getBangStrictness (Unbanged _) = notMarkedStrict
-getBangStrictness (Unpacked _) = markedUnboxed
-\end{code}
-
-
-%************************************************************************
-%* *
-\subsection{Record selectors}
-%* *
-%************************************************************************
-
-\begin{code}
-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
+ in_arg_tys pred = not $ isEmptyVarSet $
+ tyVarsOfPred pred `intersectVarSet` arg_tyvars
\end{code}
-
%************************************************************************
%* *
\subsection{Errors and contexts}
\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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