\section[TcTyDecls]{Typecheck type declarations}
\begin{code}
-module TcTyDecls ( tcTyDecl1, kcConDetails ) where
+module TcTyDecls ( tcTyDecl, checkValidTyCon, kcConDetails ) where
#include "HsVersions.h"
getBangType, getBangStrictness, conDetailsTys
)
import RnHsSyn ( RenamedTyClDecl, RenamedConDecl, RenamedContext )
-import BasicTypes ( NewOrData(..), RecFlag, isRec )
+import BasicTypes ( NewOrData(..) )
-import TcMonoType ( tcHsRecType, tcHsTyVars, tcRecTheta,
+import TcMonoType ( tcHsTyVars, tcHsTheta, tcHsType,
kcHsContext, kcHsSigType, kcHsLiftedSigType
)
import TcEnv ( tcExtendTyVarEnv,
tcLookupTyCon, tcLookupRecId,
TyThingDetails(..), RecTcEnv
)
-import TcType ( tcEqType, tyVarsOfTypes, tyVarsOfPred, Type, ThetaType )
+import TcType ( tcEqType, tyVarsOfTypes, tyVarsOfPred, ThetaType )
+import TcMType ( checkValidType, UserTypeCtxt(..), checkValidTheta, SourceTyCtxt(..) )
import TcMonad
-import DataCon ( DataCon, mkDataCon, dataConFieldLabels )
+import DataCon ( DataCon, mkDataCon, dataConFieldLabels, dataConWrapId, dataConName )
import MkId ( mkDataConId, mkDataConWrapId, mkRecordSelId )
import FieldLabel
-import Var ( TyVar )
+import Var ( TyVar, idType )
import Name ( Name, NamedThing(..) )
import Outputable
-import TyCon ( TyCon, tyConTyVars )
+import TyCon ( TyCon, tyConName, tyConTheta, getSynTyConDefn, tyConTyVars, tyConDataCons, isSynTyCon )
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 {tcdName = tycon_name, tcdSynRhs = rhs})
+tcTyDecl :: RecTcEnv -> RenamedTyClDecl -> TcM (Name, TyThingDetails)
+tcTyDecl 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)
-
+ tcHsType rhs `thenTc` \ rhs_ty ->
returnTc (tycon_name, SynTyDetails rhs_ty)
-tcTyDecl1 is_rec unf_env (TyData {tcdND = new_or_data, tcdCtxt = context,
+tcTyDecl unf_env (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
- 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 ->
+ tcHsTheta context `thenTc` \ ctxt ->
+ mapTc (tcConDecl new_or_data tycon tyvars ctxt) con_decls `thenTc` \ data_cons ->
+ let
+ sel_ids = mkRecordSelectors unf_env tycon data_cons
+ in
returnTc (tycon_name, DataTyDetails ctxt data_cons sel_ids)
-tcTyDecl1 is_rec unf_env (ForeignType {tcdName = tycon_name})
+tcTyDecl unf_env (ForeignType {tcdName = tycon_name})
= returnTc (tycon_name, ForeignTyDetails)
+
+
+mkRecordSelectors unf_env tycon data_cons
+ = -- We'll check later that fields with the same name
+ -- from different constructors have the same type.
+ [ mkRecordSelId tycon field unpack_id unpackUtf8_id
+ | field <- nubBy eq_name fields ]
+ where
+ fields = [ field | con <- data_cons, field <- dataConFieldLabels con ]
+ eq_name field1 field2 = fieldLabelName field1 == fieldLabelName field2
+
+ unpack_id = tcLookupRecId unf_env unpackCStringName
+ unpackUtf8_id = tcLookupRecId unf_env unpackCStringUtf8Name
\end{code}
%************************************************************************
%* *
+\subsection{Validity check}
+%* *
+%************************************************************************
+
+checkValidTyCon is called once the mutually-recursive knot has been
+tied, so we can look at things freely.
+
+\begin{code}
+checkValidTyCon :: TyCon -> TcM ()
+checkValidTyCon tc
+ | isSynTyCon tc = checkValidType (TySynCtxt name) syn_rhs
+ | otherwise
+ = -- Check the context on the data decl
+ checkValidTheta (DataTyCtxt name) (tyConTheta tc) `thenTc_`
+
+ -- Check arg types of data constructors
+ mapTc_ check_data_con data_cons `thenTc_`
+
+ -- Check that fields with the same name share a type
+ mapTc_ check_fields groups
+
+ where
+ name = tyConName tc
+ (_, syn_rhs) = getSynTyConDefn tc
+ data_cons = tyConDataCons tc
+
+ fields = [field | con <- data_cons, field <- dataConFieldLabels con]
+ groups = equivClasses cmp_name fields
+ cmp_name field1 field2 = fieldLabelName field1 `compare` fieldLabelName field2
+
+ check_data_con con = checkValidType (ConArgCtxt (dataConName con))
+ (idType (dataConWrapId con))
+ -- This checks the argument types and
+ -- the existential context (if any)
+
+ check_fields 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 (tcEqType 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
+\end{code}
+
+
+
+%************************************************************************
+%* *
\subsection{Kind and type check constructors}
%* *
%************************************************************************
-- 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)
+tcConDecl :: NewOrData -> TyCon -> [TyVar] -> ThetaType -> RenamedConDecl -> TcM DataCon
+tcConDecl 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 ->
+ 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
- = 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 []
+ = 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_`
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
+ 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 ->
+ = 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
%************************************************************************
%* *
-\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 (tcEqType 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}
-
-
-
-%************************************************************************
-%* *
\subsection{Errors and contexts}
%* *
%************************************************************************
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