import HsSyn ( TyClDecl(..), HsConDetails(..), HsTyVarBndr(..),
ConDecl(..), Sig(..), , NewOrData(..),
- tyClDeclTyVars, isSynDecl, LConDecl,
- LTyClDecl, tcdName, LHsTyVarBndr, LHsContext
+ tyClDeclTyVars, isSynDecl,
+ LTyClDecl, tcdName, hsTyVarName, LHsTyVarBndr
)
import HsTypes ( HsBang(..), getBangStrictness )
import BasicTypes ( RecFlag(..), StrictnessMark(..) )
-import HscTypes ( implicitTyThings )
+import HscTypes ( implicitTyThings, ModDetails )
import BuildTyCl ( buildClass, buildAlgTyCon, buildSynTyCon, buildDataCon,
mkDataTyConRhs, mkNewTyConRhs )
import TcRnMonad
-import TcEnv ( TcTyThing(..), TyThing(..),
+import TcEnv ( TyThing(..),
tcLookupLocated, tcLookupLocatedGlobal,
- tcExtendGlobalEnv, tcExtendKindEnv,
+ tcExtendGlobalEnv, tcExtendKindEnv, tcExtendKindEnvTvs,
tcExtendRecEnv, tcLookupTyVar )
import TcTyDecls ( calcTyConArgVrcs, calcRecFlags, calcClassCycles, calcSynCycles )
import TcClassDcl ( tcClassSigs, tcAddDeclCtxt )
import TcHsType ( kcHsTyVars, kcHsLiftedSigType, kcHsType,
kcHsContext, tcTyVarBndrs, tcHsKindedType, tcHsKindedContext,
- kcHsSigType, tcHsBangType, tcLHsConSig )
+ kcHsSigType, tcHsBangType, tcLHsConSig, tcDataKindSig )
import TcMType ( newKindVar, checkValidTheta, checkValidType, checkFreeness,
UserTypeCtxt(..), SourceTyCtxt(..) )
-import TcUnify ( unifyKind )
-import TcType ( TcKind, ThetaType, TcType, tyVarsOfType,
+import TcType ( TcKind, TcType, tyVarsOfType,
mkArrowKind, liftedTypeKind, mkTyVarTys, tcEqTypes,
tcSplitSigmaTy, tcEqType )
import Type ( splitTyConApp_maybe, pprThetaArrow, pprParendType )
+import Kind ( mkArrowKinds, splitKindFunTys )
import Generics ( validGenericMethodType, canDoGenerics )
import Class ( Class, className, classTyCon, DefMeth(..), classBigSig, classTyVars )
-import TyCon ( TyCon, ArgVrcs,
+import TyCon ( TyCon, ArgVrcs, AlgTyConRhs( AbstractTyCon ),
tyConDataCons, mkForeignTyCon, isProductTyCon, isRecursiveTyCon,
- tyConStupidTheta, getSynTyConDefn, tyConDataCons, isSynTyCon, tyConName )
+ tyConStupidTheta, getSynTyConDefn, isSynTyCon, tyConName )
import DataCon ( DataCon, dataConWrapId, dataConName, dataConSig,
dataConFieldLabels, dataConOrigArgTys, dataConTyCon )
import Type ( zipTopTvSubst, substTys )
import SrcLoc ( Located(..), unLoc, getLoc )
import ListSetOps ( equivClasses )
import Digraph ( SCC(..) )
-import CmdLineOpts ( DynFlag( Opt_GlasgowExts, Opt_Generics, Opt_UnboxStrictFields ) )
+import DynFlags ( DynFlag( Opt_GlasgowExts, Opt_Generics,
+ Opt_UnboxStrictFields ) )
\end{code}
@TyThing@s. @rec_vrcs@ is a finite map from @Name@s to @ArgVrcs@s.
\begin{code}
-tcTyAndClassDecls :: [Name] -> [LTyClDecl Name]
+tcTyAndClassDecls :: ModDetails -> [LTyClDecl Name]
-> TcM TcGblEnv -- Input env extended by types and classes
-- and their implicit Ids,DataCons
-tcTyAndClassDecls boot_names decls
+tcTyAndClassDecls boot_details decls
= do { -- First check for cyclic type synonysm or classes
-- See notes with checkCycleErrs
checkCycleErrs decls
; mod <- getModule
- ; traceTc (text "tcTyAndCl" <+> ppr mod <+> ppr boot_names)
+ ; traceTc (text "tcTyAndCl" <+> ppr mod)
; (syn_tycons, alg_tyclss) <- fixM (\ ~(rec_syn_tycons, rec_alg_tyclss) ->
do { let { -- Calculate variances and rec-flag
; (syn_decls, alg_decls) = partition (isSynDecl . unLoc) decls }
{ (kc_syn_decls, kc_alg_decls) <- kcTyClDecls syn_decls alg_decls
; let { calc_vrcs = calcTyConArgVrcs (rec_syn_tycons ++ rec_alg_tyclss)
- ; calc_rec = calcRecFlags boot_names rec_alg_tyclss
+ ; calc_rec = calcRecFlags boot_details rec_alg_tyclss
; tc_decl = addLocM (tcTyClDecl calc_vrcs calc_rec) }
-- Type-check the type synonyms, and extend the envt
; syn_tycons <- tcSynDecls calc_vrcs kc_syn_decls
------------------------------------------------------------------------
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,
+-- so as to maximise usefulness of error messages
+getInitialKind (L _ 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) }
+ where
+ 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
+ -- data T :: *->* where { ... }
+ mk_res_kind other = return liftedTypeKind
-getInitialKind decl
- = newKindVar `thenM` \ kind ->
- returnM (unLoc (tcdLName (unLoc decl)), kind)
----------------
kcSynDecls :: [SCC (LTyClDecl Name)]
= do { recSynErr decls; failM } -- Fail here to avoid error cascade
-- of out-of-scope tycons
+kindedTyVarKind (L _ (KindedTyVar _ k)) = k
+
------------------------------------------------------------------------
kcTyClDecl :: TyClDecl Name -> TcM (TyClDecl Name)
-- Not used for type synonyms (see kcSynDecl)
; return (ConDecl name ex_tvs' ex_ctxt' details')}
kc_con_decl (GadtDecl name ty)
= do { ty' <- kcHsSigType ty
+ ; traceTc (text "kc_con_decl" <+> ppr name <+> ppr ty')
; return (GadtDecl name ty') }
kc_con_details (PrefixCon btys)
kcTyClDecl decl@(ClassDecl {tcdCtxt = ctxt, tcdSigs = sigs})
= kcTyClDeclBody decl $ \ tvs' ->
- do { ctxt' <- kcHsContext ctxt
+ do { is_boot <- tcIsHsBoot
+ ; checkTc (not is_boot) badBootClassDeclErr
+ ; ctxt' <- kcHsContext ctxt
; sigs' <- mappM (wrapLocM kc_sig) sigs
; return (decl {tcdTyVars = tvs', tcdCtxt = ctxt', tcdSigs = sigs'}) }
where
kcTyClDeclBody :: TyClDecl Name
-> ([LHsTyVarBndr Name] -> TcM a)
-> TcM a
- -- 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
+-- getInitialKind has made a suitably-shaped kind for the type or class
+-- 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
kcTyClDeclBody decl thing_inside
= tcAddDeclCtxt decl $
- kcHsTyVars (tyClDeclTyVars decl) $ \ kinded_tvs ->
do { tc_ty_thing <- tcLookupLocated (tcdLName decl)
- ; let tc_kind = case tc_ty_thing of { AThing k -> k }
- ; unifyKind tc_kind (foldr (mkArrowKind . kindedTyVarKind)
- (result_kind decl)
- kinded_tvs)
- ; thing_inside kinded_tvs }
- where
- result_kind (TyData { tcdKindSig = Just kind }) = kind
- result_kind other = liftedTypeKind
- -- On GADT-style declarations we allow a kind signature
- -- data T :: *->* where { ... }
-
-kindedTyVarKind (L _ (KindedTyVar _ k)) = k
+ ; let tc_kind = case tc_ty_thing of { AThing k -> k }
+ (kinds, _) = splitKindFunTys tc_kind
+ hs_tvs = tcdTyVars decl
+ kinded_tvs = ASSERT( length kinds >= length hs_tvs )
+ [ L loc (KindedTyVar (hsTyVarName tv) k)
+ | (L loc tv, k) <- zip hs_tvs kinds]
+ ; tcExtendKindEnvTvs kinded_tvs (thing_inside kinded_tvs) }
\end{code}
tcTyClDecl1 calc_vrcs calc_isrec
(TyData {tcdND = new_or_data, tcdCtxt = ctxt, tcdTyVars = tvs,
- tcdLName = L _ tc_name, tcdCons = cons})
- = tcTyVarBndrs tvs $ \ tvs' -> do
- { stupid_theta <- tcStupidTheta ctxt cons
+ tcdLName = L _ tc_name, tcdKindSig = mb_ksig, tcdCons = cons})
+ = tcTyVarBndrs tvs $ \ tvs' -> do
+ { extra_tvs <- tcDataKindSig mb_ksig
+ ; let final_tvs = tvs' ++ extra_tvs
+ ; stupid_theta <- tcHsKindedContext ctxt
; want_generic <- doptM Opt_Generics
+ ; unbox_strict <- doptM Opt_UnboxStrictFields
+ ; gla_exts <- doptM Opt_GlasgowExts
+ ; is_boot <- tcIsHsBoot -- Are we compiling an hs-boot file?
+
+ -- Check that we don't use GADT syntax in H98 world
+ ; checkTc (gla_exts || h98_syntax) (badGadtDecl tc_name)
+
+ -- Check that there's at least one condecl,
+ -- or else we're reading an interface file, or -fglasgow-exts
+ ; checkTc (not (null cons) || gla_exts || is_boot)
+ (emptyConDeclsErr tc_name)
+
; tycon <- fixM (\ tycon -> do
- { unbox_strict <- doptM Opt_UnboxStrictFields
- ; gla_exts <- doptM Opt_GlasgowExts
- ; checkTc (gla_exts || h98_syntax) (badGadtDecl tc_name)
-
- ; data_cons <- mappM (addLocM (tcConDecl unbox_strict new_or_data tycon tvs')) cons
- ; let tc_rhs = case new_or_data of
- DataType -> mkDataTyConRhs stupid_theta data_cons
+ { data_cons <- mappM (addLocM (tcConDecl unbox_strict new_or_data
+ tycon final_tvs))
+ cons
+ ; let tc_rhs
+ | null cons && is_boot -- In a hs-boot file, empty cons means
+ = AbstractTyCon -- "don't know"; hence Abstract
+ | otherwise
+ = case new_or_data of
+ DataType -> mkDataTyConRhs data_cons
NewType -> ASSERT( isSingleton data_cons )
mkNewTyConRhs tycon (head data_cons)
- ; buildAlgTyCon tc_name tvs' tc_rhs arg_vrcs is_rec
+ ; buildAlgTyCon tc_name final_tvs stupid_theta tc_rhs arg_vrcs is_rec
(want_generic && canDoGenerics data_cons)
})
; return (ATyCon tycon)
; let
is_vanilla = null ex_tvs && null (unLoc ex_ctxt)
-- Vanilla iff no ex_tvs and no context
+ -- Must check the context too because of
+ -- implicit params; e.g.
+ -- data T = (?x::Int) => MkT Int
tc_datacon is_infix field_lbls btys
= do { let { bangs = map getBangStrictness btys }
; case details of
PrefixCon btys -> tc_datacon False [] btys
InfixCon bty1 bty2 -> tc_datacon True [] [bty1,bty2]
- RecCon fields -> do { checkTc is_vanilla (exRecConErr name)
+ RecCon fields -> do { checkTc (null ex_tvs) (exRecConErr name)
+ -- It's ok to have an implicit-parameter context
+ -- for the data constructor, provided it binds
+ -- no type variables
; let { (field_names, btys) = unzip fields }
; tc_datacon False field_names btys } }
tcConDecl unbox_strict DataType tycon tc_tvs -- GADTs
decl@(GadtDecl name con_ty)
= do { traceTc (text "tcConDecl" <+> ppr name)
- ; (tvs, theta, bangs, arg_tys, tc, res_tys) <- tcLHsConSig con_ty
+ ; (tvs, theta, bangs, arg_tys, data_tc, res_tys) <- tcLHsConSig con_ty
; traceTc (text "tcConDecl1" <+> ppr name)
; let -- Now dis-assemble the type, and check its form
; buildDataCon (unLoc name) False {- Not infix -} is_vanilla
(argStrictness unbox_strict tycon bangs arg_tys)
[{- No field labels -}]
- tvs' theta arg_tys' tycon res_tys' }
-
--------------------
-tcStupidTheta :: LHsContext Name -> [LConDecl Name] -> TcM (Maybe ThetaType)
--- For GADTs we don't allow a context on the data declaration
--- whereas for standard Haskell style data declarations, we do
-tcStupidTheta ctxt (L _ (ConDecl _ _ _ _) : _)
- = do { theta <- tcHsKindedContext ctxt; return (Just theta) }
-tcStupidTheta ctxt other -- Includes an empty constructor list
- = ASSERT( null (unLoc ctxt) ) return Nothing
+ tvs' theta arg_tys' data_tc res_tys' }
+ -- NB: we put data_tc, the type constructor gotten from the constructor
+ -- type signature into the data constructor; that way checkValidDataCon
+ -- can complain if it's wrong.
-------------------
argStrictness :: Bool -- True <=> -funbox-strict_fields
-- ; checkFreeness tvs ex_theta }
where
ctxt = ConArgCtxt (dataConName con)
- (tvs, ex_theta, _, _, _) = dataConSig con
+-- (tvs, ex_theta, _, _, _) = dataConSig con
-------------------------------
(ptext SLIT("In the declaration of data constructor") <+> ppr name)
badDataConTyCon data_con
- = hang (ptext SLIT("Data constructor does not return its parent type:"))
- 2 (ppr data_con)
+ = hang (ptext SLIT("Data constructor") <+> quotes (ppr data_con) <+>
+ ptext SLIT("returns type") <+> quotes (ppr (dataConTyCon data_con)))
+ 2 (ptext SLIT("instead of its parent type"))
badGadtDecl tc_name
= vcat [ ptext SLIT("Illegal generalised algebraic data declaration for") <+> quotes (ppr tc_name)
, nest 2 (parens $ ptext SLIT("Use -fglasgow-exts to allow GADTs")) ]
+
+emptyConDeclsErr tycon
+ = sep [quotes (ppr tycon) <+> ptext SLIT("has no constructors"),
+ nest 4 (ptext SLIT("(-fglasgow-exts permits this)"))]
+
+badBootClassDeclErr = ptext SLIT("Illegal class declaration in hs-boot file")
\end{code}
projects / ghc-hetmet.git / blobdiff