import HsSyn
import TcBinds ( mkPragFun, tcPrags, badBootDeclErr )
+import TcTyClsDecls ( tcIdxTyInstDecl )
import TcClassDcl ( tcMethodBind, mkMethodBind, badMethodErr,
tcClassDecl2, getGenericInstances )
import TcRnMonad
tcInstDecls1 tycl_decls inst_decls
= checkNoErrs $
- -- Stop if addInstInfos etc discovers any errors
- -- (they recover, so that we get more than one error each round)
-
- -- (1) Do the ordinary instance declarations
- mappM tcLocalInstDecl1 inst_decls `thenM` \ local_inst_infos ->
-
- let
- local_inst_info = catMaybes local_inst_infos
- clas_decls = filter (isClassDecl.unLoc) tycl_decls
- in
- -- (2) Instances from generic class declarations
- getGenericInstances clas_decls `thenM` \ generic_inst_info ->
-
- -- Next, construct the instance environment so far, consisting of
- -- a) local instance decls
- -- b) generic instances
- addInsts local_inst_info $
- addInsts generic_inst_info $
-
- -- (3) Compute instances from "deriving" clauses;
- -- This stuff computes a context for the derived instance decl, so it
- -- needs to know about all the instances possible; hence inst_env4
- tcDeriving tycl_decls `thenM` \ (deriv_inst_info, deriv_binds) ->
- addInsts deriv_inst_info $
-
- getGblEnv `thenM` \ gbl_env ->
- returnM (gbl_env,
- generic_inst_info ++ deriv_inst_info ++ local_inst_info,
- deriv_binds)
+ do { -- Stop if addInstInfos etc discovers any errors
+ -- (they recover, so that we get more than one error each
+ -- round)
+
+ -- (1) Do the ordinary instance declarations and instances of
+ -- indexed types
+ ; let { idxty_decls = filter (isIdxTyDecl . unLoc) tycl_decls }
+ ; local_inst_infos <- mappM tcLocalInstDecl1 inst_decls
+ ; idxty_inst_infos <- mappM tcIdxTyInstDecl idxty_decls
+
+ ; let { local_inst_info = concat local_inst_infos ++
+ catMaybes idxty_inst_infos
+ ; clas_decls = filter (isClassDecl.unLoc) tycl_decls }
+
+ -- (2) Instances from generic class declarations
+ ; generic_inst_info <- getGenericInstances clas_decls
+
+ -- Next, construct the instance environment so far, consisting
+ -- of
+ -- a) local instance decls
+ -- b) generic instances
+ ; addInsts local_inst_info $ do {
+ ; addInsts generic_inst_info $ do {
+
+ -- (3) Compute instances from "deriving" clauses;
+ -- This stuff computes a context for the derived instance
+ -- decl, so it needs to know about all the instances possible
+ ; (deriv_inst_info, deriv_binds) <- tcDeriving tycl_decls
+ ; addInsts deriv_inst_info $ do {
+
+ ; gbl_env <- getGblEnv
+ ; returnM (gbl_env,
+ generic_inst_info ++ deriv_inst_info ++ local_inst_info,
+ deriv_binds)
+ }}}}
addInsts :: [InstInfo] -> TcM a -> TcM a
addInsts infos thing_inside
\begin{code}
tcLocalInstDecl1 :: LInstDecl Name
- -> TcM (Maybe InstInfo) -- Nothing if there was an error
+ -> TcM [InstInfo] -- [] if there was an error
-- A source-file instance declaration
-- Type-check all the stuff before the "where"
--
-- We check for respectable instance type, and context
tcLocalInstDecl1 decl@(L loc (InstDecl poly_ty binds uprags ats))
- -- !!!TODO: Handle the `ats' parameter!!! -=chak
= -- Prime error recovery, set source location
- recoverM (returnM Nothing) $
+ recoverM (returnM []) $
setSrcSpan loc $
addErrCtxt (instDeclCtxt1 poly_ty) $
; poly_ty' <- tcHsKindedType kinded_ty
; let (tyvars, theta, tau) = tcSplitSigmaTy poly_ty'
+ -- Now, check the validity of the instance.
; (clas, inst_tys) <- checkValidInstHead tau
; checkValidInstance tyvars theta clas inst_tys
+ -- Next, process any associated types.
+ ; idxty_inst_info <- mappM tcIdxTyInstDecl ats
+
+ -- Finally, construct the Core representation of the instance.
+ -- (This no longer includes the associated types.)
; dfun_name <- newDFunName clas inst_tys (srcSpanStart loc)
; overlap_flag <- getOverlapFlag
; let dfun = mkDictFunId dfun_name tyvars theta clas inst_tys
ispec = mkLocalInstance dfun overlap_flag
- ; return (Just (InstInfo { iSpec = ispec, iBinds = VanillaInst binds uprags })) }
+ ; return $ [InstInfo { iSpec = ispec,
+ iBinds = VanillaInst binds uprags }] ++
+ catMaybes idxty_inst_info }
\end{code}
\begin{code}
module TcTyClsDecls (
- tcTyAndClassDecls
+ tcTyAndClassDecls, tcIdxTyInstDecl
) where
#include "HsVersions.h"
import HsSyn ( TyClDecl(..), HsConDetails(..), HsTyVarBndr(..),
ConDecl(..), Sig(..), NewOrData(..), ResType(..),
- tyClDeclTyVars, isSynDecl, isClassDecl, hsConArgs,
- LTyClDecl, tcdName, hsTyVarName, LHsTyVarBndr
+ tyClDeclTyVars, isSynDecl, isClassDecl, isIdxTyDecl,
+ isKindSigDecl, hsConArgs, LTyClDecl, tcdName,
+ hsTyVarName, LHsTyVarBndr, LHsType
)
import HsTypes ( HsBang(..), getBangStrictness )
import BasicTypes ( RecFlag(..), StrictnessMark(..) )
import TcClassDcl ( tcClassSigs, tcAddDeclCtxt )
import TcHsType ( kcHsTyVars, kcHsLiftedSigType, kcHsType,
kcHsContext, tcTyVarBndrs, tcHsKindedType, tcHsKindedContext,
- kcHsSigType, tcHsBangType, tcLHsConResTy, tcDataKindSig )
+ kcHsSigType, tcHsBangType, tcLHsConResTy,
+ tcDataKindSig, kcCheckHsType )
import TcMType ( newKindVar, checkValidTheta, checkValidType,
-- checkFreeness,
UserTypeCtxt(..), SourceTyCtxt(..) )
mkArrowKind, liftedTypeKind, mkTyVarTys,
tcSplitSigmaTy, tcEqTypes, tcGetTyVar_maybe )
import Type ( PredType(..), splitTyConApp_maybe, mkTyVarTy,
- newTyConInstRhs
+ newTyConInstRhs, isLiftedTypeKind, Kind
-- pprParendType, pprThetaArrow
)
import Generics ( validGenericMethodType, canDoGenerics )
import VarSet ( elemVarSet, mkVarSet )
import Name ( Name, getSrcLoc )
import Outputable
-import Maybe ( isJust )
+import Maybe ( isJust, fromJust, isNothing )
import Maybes ( expectJust )
import Unify ( tcMatchTys, tcMatchTyX )
import Util ( zipLazy, isSingleton, notNull, sortLe )
tcTyAndClassDecls :: ModDetails -> [LTyClDecl Name]
-> TcM TcGblEnv -- Input env extended by types and classes
-- and their implicit Ids,DataCons
-tcTyAndClassDecls boot_details decls
- = do { -- First check for cyclic type synonysm or classes
+tcTyAndClassDecls boot_details allDecls
+ = do { -- Omit instances of indexed types; they are handled together
+ -- with the *heads* of class instances
+ ; let decls = filter (not . isIdxTyDecl . unLoc) allDecls
+
+ -- First check for cyclic type synonysm or classes
-- See notes with checkCycleErrs
- checkCycleErrs decls
+ ; checkCycleErrs decls
; mod <- getModule
; traceTc (text "tcTyAndCl" <+> ppr mod)
; (syn_tycons, alg_tyclss) <- fixM (\ ~(rec_syn_tycons, rec_alg_tyclss) ->
%************************************************************************
%* *
+\subsection{Type checking instances of indexed types}
+%* *
+%************************************************************************
+
+Instances of indexed types are somewhat of a hybrid. They are processed
+together with class instance heads, but can contain data constructors and hence
+they share a lot of kinding and type checking code with ordinary algebraic
+data types (and GADTs).
+
+\begin{code}
+tcIdxTyInstDecl :: LTyClDecl Name -> TcM (Maybe InstInfo) -- Nothing if error
+tcIdxTyInstDecl (L loc decl)
+ = -- Prime error recovery, set source location
+ recoverM (returnM Nothing) $
+ setSrcSpan loc $
+ tcAddDeclCtxt decl $
+ do { -- indexed data types require -fglasgow-exts and can't be in an
+ -- hs-boot file
+ ; gla_exts <- doptM Opt_GlasgowExts
+ ; is_boot <- tcIsHsBoot -- Are we compiling an hs-boot file?
+ ; checkTc gla_exts $ badIdxTyDecl (tcdLName decl)
+ ; checkTc (not is_boot) $ badBootTyIdxDeclErr
+
+ -- perform kind and type checking
+ ; tcIdxTyInstDecl1 decl
+ }
+
+tcIdxTyInstDecl1 :: TyClDecl Name -> TcM (Maybe InstInfo) -- Nothing if error
+
+tcIdxTyInstDecl1 (decl@TySynonym {})
+ = kcIdxTyPats decl $ \k_tvs k_typats resKind ->
+ do { -- kind check the right hand side of the type equation
+ ; k_rhs <- kcCheckHsType (tcdSynRhs decl) resKind
+
+ -- type check type equation
+ ; tcTyVarBndrs k_tvs $ \t_tvs -> do {
+ ; t_typats <- mappM tcHsKindedType k_typats
+ ; t_rhs <- tcHsKindedType k_rhs
+
+ -- construct type rewrite rule
+ -- !!!of the form: forall t_tvs. (tcdLName decl) t_typats = t_rhs
+ ; return Nothing -- !!!TODO: need InstInfo for indexed types
+ }}
+
+tcIdxTyInstDecl1 (decl@TyData {tcdND = new_or_data, tcdLName = L _ tc_name,
+ tcdCons = cons})
+ = kcIdxTyPats decl $ \k_tvs k_typats resKind ->
+ do { -- kind check the data declaration as usual
+ ; k_decl <- kcDataDecl decl k_tvs
+ ; k_typats <- mappM tcHsKindedType k_typats
+ ; let k_ctxt = tcdCtxt decl
+ k_cons = tcdCons decl
+
+ -- result kind must be '*' (otherwise, we have too few patterns)
+ ; checkTc (isLiftedTypeKind resKind) $ tooFewParmsErr tc_name
+
+ -- type check indexed data type declaration
+ ; tcTyVarBndrs k_tvs $ \t_tvs -> do {
+ ; unbox_strict <- doptM Opt_UnboxStrictFields
+
+ -- Check that we don't use GADT syntax for indexed types
+ ; checkTc h98_syntax (badGadtIdxTyDecl tc_name)
+
+ -- Check that a newtype has exactly one constructor
+ ; checkTc (new_or_data == DataType || isSingleton cons) $
+ newtypeConError tc_name (length cons)
+
+ ; stupid_theta <- tcHsKindedContext k_ctxt
+ ; tycon <- fixM (\ tycon -> do
+ { data_cons <- mappM (addLocM (tcConDecl unbox_strict new_or_data
+ tycon t_tvs))
+ k_cons
+ ; tc_rhs <-
+ case new_or_data of
+ DataType -> return (mkDataTyConRhs data_cons)
+ NewType ->
+ ASSERT( isSingleton data_cons )
+ mkNewTyConRhs tc_name tycon (head data_cons)
+ --vvvvvvv !!! need a new derived tc_name here
+ ; buildAlgTyCon tc_name t_tvs stupid_theta tc_rhs Recursive
+ False h98_syntax
+ -- We always assume that indexed types are recursive. Why?
+ -- (1) Due to their open nature, we can never be sure that a
+ -- further instance might not introduce a new recursive
+ -- dependency. (2) They are always valid loop breakers as
+ -- they involve a coercion.
+ })
+
+ -- construct result
+ -- !!!twofold: (1) (ATyCon tycon) and (2) an equality axiom
+ ; return Nothing -- !!!TODO: need InstInfo for indexed types
+ }}
+ where
+ h98_syntax = case cons of -- All constructors have same shape
+ L _ (ConDecl { con_res = ResTyGADT _ }) : _ -> False
+ other -> True
+
+-- Kind checking of indexed types
+-- -
+
+-- Kind check type patterns and kind annotate the embedded type variables.
+--
+-- * Here we check that a type instance matches its kind signature, but we do
+-- not check whether there is a pattern for each type index; the latter
+-- check is only required for type functions.
+--
+kcIdxTyPats :: TyClDecl Name
+ -> ([LHsTyVarBndr Name] -> [LHsType Name] -> Kind -> TcM a)
+ -- ^^kinded tvs ^^kinded ty pats ^^res kind
+ -> TcM a
+kcIdxTyPats decl thing_inside
+ = kcHsTyVars (tcdTyVars decl) $ \tvs ->
+ do { tc_ty_thing <- tcLookupLocated (tcdLName decl)
+ ; let tc_kind = case tc_ty_thing of { AThing k -> k }
+ (kinds, resKind) = splitKindFunTys tc_kind
+ hs_typats = fromJust $ tcdTyPats decl
+
+ -- we may not have more parameters than the kind indicates
+ ; checkTc (length kinds >= length hs_typats) $
+ tooManyParmsErr (tcdLName decl)
+
+ -- type functions can have a higher-kinded result
+ ; let resultKind = mkArrowKinds (drop (length hs_typats) kinds) resKind
+ ; typats <- zipWithM kcCheckHsType hs_typats kinds
+ ; thing_inside tvs typats resultKind
+ }
+\end{code}
+
+
+%************************************************************************
+%* *
Kind checking
%* *
%************************************************************************
use them, whereas for the mutually recursive data types D we bring into
scope kind bindings D -> k, where k is a kind variable, and do inference.
+Indexed Types
+~~~~~~~~~~~~~
+This treatment of type synonyms only applies to Haskell 98-style synonyms.
+General type functions can be recursive, and hence, appear in `alg_decls'.
+
+The kind of an indexed type is solely determinded by its kind signature;
+hence, only kind signatures participate in the construction of the initial
+kind environment (as constructed by `getInitialKind'). In fact, we ignore
+instances of indexed types altogether in the following. However, we need to
+include the kind signatures of associated types into the construction of the
+initial kind environment. (This is handled by `allDecls').
+
\begin{code}
kcTyClDecls syn_decls alg_decls
- = do { -- First extend the kind env with each data
- -- type and class, mapping them to a type variable
- alg_kinds <- mappM getInitialKind alg_decls
+ = do { -- First extend the kind env with each data type, class, and
+ -- indexed type, mapping them to a type variable
+ let initialKindDecls = concat [allDecls decl | L _ decl <- alg_decls]
+ ; alg_kinds <- mappM getInitialKind initialKindDecls
; tcExtendKindEnv alg_kinds $ do
-- Now kind-check the type synonyms, in dependency order
{ (kc_syn_decls, syn_kinds) <- kcSynDecls (calcSynCycles syn_decls)
; tcExtendKindEnv syn_kinds $ do
- -- Now kind-check the data type and class declarations,
- -- returning kind-annotated decls
- { kc_alg_decls <- mappM (wrapLocM kcTyClDecl) alg_decls
+ -- Now kind-check the data type, class, and kind signatures,
+ -- returning kind-annotated decls; we don't kind-check
+ -- instances of indexed types yet, but leave this to
+ -- `tcInstDecls1'
+ { kc_alg_decls <- mappM (wrapLocM kcTyClDecl)
+ (filter (not . isIdxTyDecl . unLoc) alg_decls)
; return (kc_syn_decls, kc_alg_decls) }}}
+ where
+ -- get all declarations relevant for determining the initial kind
+ -- environment
+ allDecls (decl@ClassDecl {tcdATs = ats}) = decl : [ at
+ | L _ at <- ats
+ , isKindSigDecl at]
+ allDecls decl | isIdxTyDecl decl = []
+ | otherwise = [decl]
------------------------------------------------------------------------
-getInitialKind :: LTyClDecl Name -> TcM (Name, TcKind)
--- Only for data type and class declarations
--- Get as much info as possible from the data or class decl,
+getInitialKind :: TyClDecl Name -> TcM (Name, TcKind)
+-- Only for data type, class, and indexed type declarations
+-- Get as much info as possible from the data, class, or indexed type decl,
-- so as to maximise usefulness of error messages
-getInitialKind (L _ decl)
+getInitialKind decl
= do { arg_kinds <- mapM (mk_arg_kind . unLoc) (tyClDeclTyVars decl)
; res_kind <- mk_res_kind decl
; return (tcdName decl, mkArrowKinds arg_kinds res_kind) }
mk_arg_kind (UserTyVar _) = newKindVar
mk_arg_kind (KindedTyVar _ kind) = return kind
- mk_res_kind (TyData { tcdKindSig = Just kind }) = return kind
- -- On GADT-style declarations we allow a kind signature
+ mk_res_kind (TyFunction { tcdKind = kind }) = return kind
+ mk_res_kind (TyData { tcdKindSig = Just kind }) = return kind
+ -- On GADT-style and data signature declarations we allow a kind
+ -- signature
-- data T :: *->* where { ... }
mk_res_kind other = return liftedTypeKind
kcTyClDecl :: TyClDecl Name -> TcM (TyClDecl Name)
-- Not used for type synonyms (see kcSynDecl)
-kcTyClDecl decl@(TyData {tcdND = new_or_data, tcdCtxt = ctxt, tcdCons = cons})
- = kcTyClDeclBody decl $ \ tvs' ->
- do { ctxt' <- kcHsContext ctxt
- ; cons' <- mappM (wrapLocM kc_con_decl) cons
- ; return (decl {tcdTyVars = tvs', tcdCtxt = ctxt', tcdCons = cons'}) }
- where
- kc_con_decl (ConDecl name expl ex_tvs ex_ctxt details res) = do
- kcHsTyVars ex_tvs $ \ex_tvs' -> do
- ex_ctxt' <- kcHsContext ex_ctxt
- details' <- kc_con_details details
- res' <- case res of
- ResTyH98 -> return ResTyH98
- ResTyGADT ty -> do { ty' <- kcHsSigType ty; return (ResTyGADT ty') }
- return (ConDecl name expl ex_tvs' ex_ctxt' details' res')
-
- kc_con_details (PrefixCon btys)
- = do { btys' <- mappM kc_larg_ty btys ; return (PrefixCon btys') }
- kc_con_details (InfixCon bty1 bty2)
- = do { bty1' <- kc_larg_ty bty1; bty2' <- kc_larg_ty bty2; return (InfixCon bty1' bty2') }
- kc_con_details (RecCon fields)
- = do { fields' <- mappM kc_field fields; return (RecCon fields') }
+kcTyClDecl decl@(TyData {})
+ = ASSERT( not . isJust $ tcdTyPats decl ) -- must not be instance of idx ty
+ kcTyClDeclBody decl $
+ kcDataDecl decl
- kc_field (fld, bty) = do { bty' <- kc_larg_ty bty ; return (fld, bty') }
+kcTyClDecl decl@(TyFunction {})
+ = kcTyClDeclBody decl $ \ tvs' ->
+ return (decl {tcdTyVars = tvs'})
- kc_larg_ty bty = case new_or_data of
- DataType -> kcHsSigType bty
- NewType -> kcHsLiftedSigType bty
- -- Can't allow an unlifted type for newtypes, because we're effectively
- -- going to remove the constructor while coercing it to a lifted type.
- -- And newtypes can't be bang'd
-
--- !!!TODO -=chak
-kcTyClDecl decl@(ClassDecl {tcdCtxt = ctxt, tcdSigs = sigs})
+kcTyClDecl decl@(ClassDecl {tcdCtxt = ctxt, tcdSigs = sigs, tcdATs = ats})
= kcTyClDeclBody decl $ \ tvs' ->
do { is_boot <- tcIsHsBoot
; ctxt' <- kcHsContext ctxt
- ; sigs' <- mappM (wrapLocM kc_sig) sigs
- ; return (decl {tcdTyVars = tvs', tcdCtxt = ctxt', tcdSigs = sigs'}) }
+ ; ats' <- mappM (wrapLocM kcTyClDecl) ats
+ ; sigs' <- mappM (wrapLocM kc_sig ) sigs
+ ; return (decl {tcdTyVars = tvs', tcdCtxt = ctxt', tcdSigs = sigs',
+ tcdATs = ats'}) }
where
kc_sig (TypeSig nm op_ty) = do { op_ty' <- kcHsLiftedSigType op_ty
; return (TypeSig nm op_ty') }
-- Unpack it, and attribute those kinds to the type variables
-- Extend the env with bindings for the tyvars, taken from
-- the kind of the tycon/class. Give it to the thing inside, and
- -- check the result kind matches
+-- check the result kind matches
kcTyClDeclBody decl thing_inside
= tcAddDeclCtxt decl $
do { tc_ty_thing <- tcLookupLocated (tcdLName decl)
[ L loc (KindedTyVar (hsTyVarName tv) k)
| (L loc tv, k) <- zip hs_tvs kinds]
; tcExtendKindEnvTvs kinded_tvs (thing_inside kinded_tvs) }
+
+-- Kind check a data declaration, assuming that we already extended the
+-- kind environment with the type variables of the left-hand side (these
+-- kinded type variables are also passed as the second parameter).
+--
+kcDataDecl :: TyClDecl Name -> [LHsTyVarBndr Name] -> TcM (TyClDecl Name)
+kcDataDecl decl@(TyData {tcdND = new_or_data, tcdCtxt = ctxt, tcdCons = cons})
+ tvs
+ = do { ctxt' <- kcHsContext ctxt
+ ; cons' <- mappM (wrapLocM kc_con_decl) cons
+ ; return (decl {tcdTyVars = tvs, tcdCtxt = ctxt', tcdCons = cons'}) }
+ where
+ kc_con_decl (ConDecl name expl ex_tvs ex_ctxt details res) = do
+ kcHsTyVars ex_tvs $ \ex_tvs' -> do
+ ex_ctxt' <- kcHsContext ex_ctxt
+ details' <- kc_con_details details
+ res' <- case res of
+ ResTyH98 -> return ResTyH98
+ ResTyGADT ty -> do { ty' <- kcHsSigType ty; return (ResTyGADT ty') }
+ return (ConDecl name expl ex_tvs' ex_ctxt' details' res')
+
+ kc_con_details (PrefixCon btys)
+ = do { btys' <- mappM kc_larg_ty btys ; return (PrefixCon btys') }
+ kc_con_details (InfixCon bty1 bty2)
+ = do { bty1' <- kc_larg_ty bty1; bty2' <- kc_larg_ty bty2; return (InfixCon bty1' bty2') }
+ kc_con_details (RecCon fields)
+ = do { fields' <- mappM kc_field fields; return (RecCon fields') }
+
+ kc_field (fld, bty) = do { bty' <- kc_larg_ty bty ; return (fld, bty') }
+
+ kc_larg_ty bty = case new_or_data of
+ DataType -> kcHsSigType bty
+ NewType -> kcHsLiftedSigType bty
+ -- Can't allow an unlifted type for newtypes, because we're effectively
+ -- going to remove the constructor while coercing it to a lifted type.
+ -- And newtypes can't be bang'd
\end{code}
tcTyClDecl calc_isrec decl
= tcAddDeclCtxt decl (tcTyClDecl1 calc_isrec decl)
-tcTyClDecl1 calc_isrec
+ -- kind signature for a type functions
+tcTyClDecl1 _calc_isrec
+ (TyFunction {tcdLName = L _ tc_name, tcdTyVars = tvs, tcdKind = kind})
+ = tcKindSigDecl tc_name tvs kind
+
+ -- kind signature for an indexed data type
+tcTyClDecl1 _calc_isrec
+ (TyData {tcdCtxt = ctxt, tcdTyVars = tvs,
+ tcdLName = L _ tc_name, tcdKindSig = Just kind, tcdCons = []})
+ = do
+ { checkTc (null . unLoc $ ctxt) $ badKindSigCtxt tc_name
+ ; tcKindSigDecl tc_name tvs kind
+ }
+
+tcTyClDecl1 calc_isrec
(TyData {tcdND = new_or_data, tcdCtxt = ctxt, tcdTyVars = tvs,
tcdLName = L _ tc_name, tcdKindSig = mb_ksig, tcdCons = cons})
= tcTyVarBndrs tvs $ \ tvs' -> do
-- Check that we don't use GADT syntax in H98 world
; checkTc (gla_exts || h98_syntax) (badGadtDecl tc_name)
+ -- Check that we don't use kind signatures without Glasgow extensions
+ ; checkTc (gla_exts || isNothing mb_ksig) (badSigTyDecl tc_name)
+
-- Check that the stupid theta is empty for a GADT-style declaration
; checkTc (null stupid_theta || h98_syntax) (badStupidTheta tc_name)
= tcTyVarBndrs tvs $ \ tvs' -> do
{ ctxt' <- tcHsKindedContext ctxt
; fds' <- mappM (addLocM tc_fundep) fundeps
- -- !!!TODO: process `ats`; what do we want to store in the `Class'? -=chak
+ ; ats' <- mappM (addLocM (tcTyClDecl1 (const Recursive))) ats
+ -- ^^^^ !!!TODO: what to do with this? Need to generate FC tyfun decls.
; sig_stuff <- tcClassSigs class_name sigs meths
; clas <- fixM (\ clas ->
let -- This little knot is just so we can get
-- hold of the name of the class TyCon, which we
- -- need to look up its recursiveness and variance
+ -- need to look up its recursiveness
tycon_name = tyConName (classTyCon clas)
tc_isrec = calc_isrec tycon_name
in
= returnM (ATyCon (mkForeignTyCon tc_name tc_ext_name liftedTypeKind 0))
-----------------------------------
+tcKindSigDecl :: Name -> [LHsTyVarBndr Name] -> Kind -> TcM TyThing
+tcKindSigDecl tc_name tvs kind
+ = tcTyVarBndrs tvs $ \ tvs' -> do
+ { gla_exts <- doptM Opt_GlasgowExts
+
+ -- Check that we don't use kind signatures without Glasgow extensions
+ ; checkTc gla_exts $ badSigTyDecl tc_name
+
+ -- !!!TODO
+ -- We need to extend TyCon.TyCon with a new variant representing indexed
+ -- type constructors (ie, IdxTyCon). We will use them for both indexed
+ -- data types as well as type functions. In the case of indexed *data*
+ -- types, they are *abstract*; ie, won't be rewritten. OR do we just want
+ -- to make another variant of AlgTyCon (after all synonyms are also
+ -- AlgTyCons...)
+ -- We need an additional argument to this functions, which determines
+ -- whether the type constructor is abstract.
+ ; tycon <- error "TcTyClsDecls.tcKindSigDecl: IdxTyCon not implemented yet."
+ ; return (ATyCon tycon)
+ }
+
+-----------------------------------
tcConDecl :: Bool -- True <=> -funbox-strict_fields
-> NewOrData -> TyCon -> [TyVar]
-> ConDecl Name -> TcM DataCon
-- class has only one parameter. We can't do generic
-- multi-parameter type classes!
; checkTc (unary || no_generics) (genericMultiParamErr cls)
-
- -- Check that the class has no associated types, unless GlaExs
- ; checkTc (gla_exts || no_ats) (badATDecl cls)
}
where
(tyvars, theta, _, op_stuff) = classBigSig cls
unary = isSingleton tyvars
no_generics = null [() | (_, GenDefMeth) <- op_stuff]
- no_ats = True -- !!!TODO: determine whether the class has ATs -=chak
check_op gla_exts (sel_id, dm)
= addErrCtxt (classOpCtxt sel_id tau) $ do
= sep [ptext SLIT("The constructor of a newtype must have exactly one field"),
nest 2 $ ptext SLIT("but") <+> quotes (ppr con_name) <+> ptext SLIT("has") <+> speakN n_flds]
-badATDecl cl_name
- = vcat [ ptext SLIT("Illegal associated type declaration in") <+> quotes (ppr cl_name)
- , nest 2 (parens $ ptext SLIT("Use -fglasgow-exts to allow ATs")) ]
+badSigTyDecl tc_name
+ = vcat [ ptext SLIT("Illegal kind signature") <+>
+ quotes (ppr tc_name)
+ , nest 2 (parens $ ptext SLIT("Use -fglasgow-exts to allow indexed types")) ]
+
+badKindSigCtxt tc_name
+ = vcat [ ptext SLIT("Illegal context in kind signature") <+>
+ quotes (ppr tc_name)
+ , nest 2 (parens $ ptext SLIT("Currently, kind signatures cannot have a context")) ]
+
+badIdxTyDecl tc_name
+ = vcat [ ptext SLIT("Illegal indexed type instance for") <+>
+ quotes (ppr tc_name)
+ , nest 2 (parens $ ptext SLIT("Use -fglasgow-exts to allow indexed types")) ]
+
+badGadtIdxTyDecl tc_name
+ = vcat [ ptext SLIT("Illegal generalised algebraic data declaration for") <+>
+ quotes (ppr tc_name)
+ , nest 2 (parens $ ptext SLIT("Indexed types cannot use GADT declarations")) ]
+
+tooManyParmsErr tc_name
+ = ptext SLIT("Indexed type instance has too many parameters:") <+>
+ quotes (ppr tc_name)
+
+tooFewParmsErr tc_name
+ = ptext SLIT("Indexed type instance has too few parameters:") <+>
+ quotes (ppr tc_name)
+
+badBootTyIdxDeclErr = ptext SLIT("Illegal indexed type instance in hs-boot file")
emptyConDeclsErr tycon
= sep [quotes (ppr tycon) <+> ptext SLIT("has no constructors"),
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