X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=compiler%2Ftypecheck%2FTcTyClsDecls.lhs;h=9e302c3a6168517439296fa036d235ce9b6df19a;hb=fcb83d8469d4d7f282754387369aa86d40429dcf;hp=a1ca8cab87b0a78a82047aaf1f0322b45bba138a;hpb=70918cf4a4d61d4752b18f29ce14c7d7f1fbce01;p=ghc-hetmet.git diff --git a/compiler/typecheck/TcTyClsDecls.lhs b/compiler/typecheck/TcTyClsDecls.lhs index a1ca8ca..9e302c3 100644 --- a/compiler/typecheck/TcTyClsDecls.lhs +++ b/compiler/typecheck/TcTyClsDecls.lhs @@ -44,7 +44,7 @@ import ListSetOps import Digraph import DynFlags -import Data.List ( partition, elemIndex ) +import Data.List import Control.Monad ( mplus ) \end{code} @@ -133,7 +133,7 @@ tcTyAndClassDecls :: ModDetails -> [LTyClDecl Name] -> TcM TcGblEnv -- Input env extended by types and classes -- and their implicit Ids,DataCons tcTyAndClassDecls boot_details allDecls - = do { -- Omit instances of indexed types; they are handled together + = do { -- Omit instances of type families; they are handled together -- with the *heads* of class instances ; let decls = filter (not . isFamInstDecl . unLoc) allDecls @@ -239,9 +239,9 @@ tcFamInstDecl (L loc decl) recoverM (returnM Nothing) $ setSrcSpan loc $ tcAddDeclCtxt decl $ - do { -- type families require -findexed-types and can't be in an + do { -- type families require -ftype-families and can't be in an -- hs-boot file - ; gla_exts <- doptM Opt_IndexedTypes + ; gla_exts <- doptM Opt_TypeFamilies ; is_boot <- tcIsHsBoot -- Are we compiling an hs-boot file? ; checkTc gla_exts $ badFamInstDecl (tcdLName decl) ; checkTc (not is_boot) $ badBootFamInstDeclErr @@ -252,13 +252,14 @@ tcFamInstDecl (L loc decl) tcFamInstDecl1 :: TyClDecl Name -> TcM (Maybe TyThing) -- Nothing if error -tcFamInstDecl1 (decl@TySynonym {}) + -- "type instance" +tcFamInstDecl1 (decl@TySynonym {tcdLName = L loc tc_name}) = kcIdxTyPats decl $ \k_tvs k_typats resKind family -> do { -- check that the family declaration is for a synonym unless (isSynTyCon family) $ addErr (wrongKindOfFamily family) - ; -- (1) kind check the right hand side of the type equation + ; -- (1) kind check the right-hand side of the type equation ; k_rhs <- kcCheckHsType (tcdSynRhs decl) resKind -- (2) type check type equation @@ -266,16 +267,29 @@ tcFamInstDecl1 (decl@TySynonym {}) ; t_typats <- mappM tcHsKindedType k_typats ; t_rhs <- tcHsKindedType k_rhs - -- !!!of the form: forall t_tvs. (tcdLName decl) t_typats = t_rhs - ; return Nothing -- !!!TODO: need TyThing for indexed synonym + -- (3) check that + -- - left-hand side contains no type family applications + -- (vanilla synonyms are fine, though) + ; mappM_ checkTyFamFreeness t_typats + + -- - the right-hand side is a tau type + ; unless (isTauTy t_rhs) $ + addErr (polyTyErr t_rhs) + + -- (4) construct representation tycon + ; rep_tc_name <- newFamInstTyConName tc_name loc + ; tycon <- buildSynTyCon rep_tc_name t_tvs (SynonymTyCon t_rhs) + (Just (family, t_typats)) + + ; return $ Just (ATyCon tycon) }} - + + -- "newtype instance" and "data instance" tcFamInstDecl1 (decl@TyData {tcdND = new_or_data, tcdLName = L loc tc_name, tcdCons = cons}) = kcIdxTyPats decl $ \k_tvs k_typats resKind family -> do { -- check that the family declaration is for the right kind - unless (new_or_data == NewType && isNewTyCon family || - new_or_data == DataType && isDataTyCon family) $ + unless (isAlgTyCon family) $ addErr (wrongKindOfFamily family) ; -- (1) kind check the data declaration as usual @@ -290,17 +304,24 @@ tcFamInstDecl1 (decl@TyData {tcdND = new_or_data, tcdLName = L loc tc_name, ; tcTyVarBndrs k_tvs $ \t_tvs -> do { -- turn kinded into proper tyvars ; unbox_strict <- doptM Opt_UnboxStrictFields - -- Check that we don't use GADT syntax for indexed types + -- kind check the type indexes and the context + ; t_typats <- mappM tcHsKindedType k_typats + ; stupid_theta <- tcHsKindedContext k_ctxt + + -- (3) Check that + -- - left-hand side contains no type family applications + -- (vanilla synonyms are fine, though) + ; mappM_ checkTyFamFreeness t_typats + + -- - we don't use GADT syntax for indexed types ; checkTc h98_syntax (badGadtIdxTyDecl tc_name) - -- Check that a newtype has exactly one constructor + -- - a newtype has exactly one constructor ; checkTc (new_or_data == DataType || isSingleton k_cons) $ newtypeConError tc_name (length k_cons) - ; t_typats <- mappM tcHsKindedType k_typats - ; stupid_theta <- tcHsKindedContext k_ctxt - - ; rep_tc_name <- newFamInstTyConName tc_name (srcSpanStart loc) + -- (4) construct representation tycon + ; rep_tc_name <- newFamInstTyConName tc_name loc ; tycon <- fixM (\ tycon -> do { data_cons <- mappM (addLocM (tcConDecl unbox_strict tycon t_tvs)) k_cons @@ -308,7 +329,7 @@ tcFamInstDecl1 (decl@TyData {tcdND = new_or_data, tcdLName = L loc tc_name, case new_or_data of DataType -> return (mkDataTyConRhs data_cons) NewType -> ASSERT( isSingleton data_cons ) - mkNewTyConRhs tc_name tycon (head data_cons) + mkNewTyConRhs rep_tc_name tycon (head data_cons) ; buildAlgTyCon rep_tc_name t_tvs stupid_theta tc_rhs Recursive False h98_syntax (Just (family, t_typats)) -- We always assume that indexed types are recursive. Why? @@ -326,6 +347,27 @@ tcFamInstDecl1 (decl@TyData {tcdND = new_or_data, tcdLName = L loc tc_name, L _ (ConDecl { con_res = ResTyGADT _ }) : _ -> False other -> True +-- Check that a type index does not contain any type family applications +-- +-- * Earlier phases have already checked that there are no foralls in the +-- type; we also cannot have PredTys and NoteTys are being skipped by using +-- the core view. +-- +checkTyFamFreeness :: Type -> TcM () +checkTyFamFreeness ty | Just (tycon, tys) <- splitTyConApp_maybe ty + = if isSynTyCon tycon + then addErr $ tyFamAppInIndexErr ty + else mappM_ checkTyFamFreeness tys + -- splitTyConApp_maybe uses the core view; hence, + -- any synonym tycon must be a family tycon + + | Just (ty1, ty2) <- splitAppTy_maybe ty + = checkTyFamFreeness ty1 >> checkTyFamFreeness ty2 + + | otherwise -- only vars remaining + = return () + + -- Kind checking of indexed types -- - @@ -333,7 +375,7 @@ tcFamInstDecl1 (decl@TyData {tcdND = new_or_data, tcdLName = L loc tc_name, -- -- * 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. +-- check is only required for type synonym instances. -- kcIdxTyPats :: TyClDecl Name -> ([LHsTyVarBndr Name] -> [LHsType Name] -> Kind -> TyCon -> TcM a) @@ -386,7 +428,7 @@ So we must infer their kinds from their right-hand sides *first* and then 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 +Type families ~~~~~~~~~~~~~ This treatment of type synonyms only applies to Haskell 98-style synonyms. General type functions can be recursive, and hence, appear in `alg_decls'. @@ -562,7 +604,8 @@ kcDataDecl decl@(TyData {tcdND = new_or_data, tcdCtxt = ctxt, tcdCons = cons}) kc_con_details (RecCon fields) = do { fields' <- mappM kc_field fields; return (RecCon fields') } - kc_field (HsRecField fld bty d) = do { bty' <- kc_larg_ty bty ; return (HsRecField fld bty' d) } + kc_field (ConDeclField fld bty d) = do { bty' <- kc_larg_ty bty + ; return (ConDeclField fld bty' d) } kc_larg_ty bty = case new_or_data of DataType -> kcHsSigType bty @@ -587,12 +630,15 @@ tcSynDecls (decl : decls) ; syn_tcs <- tcExtendGlobalEnv [syn_tc] (tcSynDecls decls) ; return (syn_tc : syn_tcs) } + -- "type" tcSynDecl (TySynonym {tcdLName = L _ tc_name, tcdTyVars = tvs, tcdSynRhs = rhs_ty}) = tcTyVarBndrs tvs $ \ tvs' -> do { traceTc (text "tcd1" <+> ppr tc_name) ; rhs_ty' <- tcHsKindedType rhs_ty - ; return (ATyCon (buildSynTyCon tc_name tvs' (SynonymTyCon rhs_ty'))) } + ; tycon <- buildSynTyCon tc_name tvs' (SynonymTyCon rhs_ty') Nothing + ; return (ATyCon tycon) + } -------------------- tcTyClDecl :: (Name -> RecFlag) -> TyClDecl Name -> TcM [TyThing] @@ -609,37 +655,35 @@ tcTyClDecl1 _calc_isrec -- kind checking = tcTyVarBndrs tvs $ \ tvs' -> do { traceTc (text "type family: " <+> ppr tc_name) - ; idx_tys <- doptM Opt_IndexedTypes + ; idx_tys <- doptM Opt_TypeFamilies - -- Check that we don't use families without -findexed-types + -- Check that we don't use families without -ftype-families ; checkTc idx_tys $ badFamInstDecl tc_name - ; return [ATyCon $ buildSynTyCon tc_name tvs' (OpenSynTyCon kind Nothing)] + ; tycon <- buildSynTyCon tc_name tvs' (OpenSynTyCon kind Nothing) Nothing + ; return [ATyCon tycon] } -- "newtype family" or "data family" declaration tcTyClDecl1 _calc_isrec - (TyFamily {tcdFlavour = DataFamily new_or_data, + (TyFamily {tcdFlavour = DataFamily, tcdLName = L _ tc_name, tcdTyVars = tvs, tcdKind = mb_kind}) = tcTyVarBndrs tvs $ \ tvs' -> do - { traceTc (text "data/newtype family: " <+> ppr tc_name) + { traceTc (text "data family: " <+> ppr tc_name) ; extra_tvs <- tcDataKindSig mb_kind ; let final_tvs = tvs' ++ extra_tvs -- we may not need these - ; idx_tys <- doptM Opt_IndexedTypes + ; idx_tys <- doptM Opt_TypeFamilies - -- Check that we don't use families without -findexed-types + -- Check that we don't use families without -ftype-families ; checkTc idx_tys $ badFamInstDecl tc_name ; tycon <- buildAlgTyCon tc_name final_tvs [] - (case new_or_data of - DataType -> mkOpenDataTyConRhs - NewType -> mkOpenNewTyConRhs) - Recursive False True Nothing + mkOpenDataTyConRhs Recursive False True Nothing ; return [ATyCon tycon] } - -- "newtype", "data", "newtype instance", "data instance" + -- "newtype" and "data" tcTyClDecl1 calc_isrec (TyData {tcdND = new_or_data, tcdCtxt = ctxt, tcdTyVars = tvs, tcdLName = L _ tc_name, tcdKindSig = mb_ksig, tcdCons = cons}) @@ -649,21 +693,23 @@ tcTyClDecl1 calc_isrec ; stupid_theta <- tcHsKindedContext ctxt ; want_generic <- doptM Opt_Generics ; unbox_strict <- doptM Opt_UnboxStrictFields - ; gla_exts <- doptM Opt_GlasgowExts + ; empty_data_decls <- doptM Opt_EmptyDataDecls + ; kind_signatures <- doptM Opt_KindSignatures + ; gadt_ok <- doptM Opt_GADTs ; 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) + ; checkTc (gadt_ok || 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) + ; checkTc (kind_signatures || 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) -- Check that there's at least one condecl, - -- or else we're reading an hs-boot file, or -fglasgow-exts - ; checkTc (not (null cons) || gla_exts || is_boot) + -- or else we're reading an hs-boot file, or -XEmptyDataDecls + ; checkTc (not (null cons) || empty_data_decls || is_boot) (emptyConDeclsErr tc_name) -- Check that a newtype has exactly one constructor @@ -768,8 +814,8 @@ tcConDecl unbox_strict tycon tc_tvs -- Data types InfixCon bty1 bty2 -> tc_datacon True [] [bty1,bty2] RecCon fields -> tc_datacon False field_names btys where - (field_names, btys) = unzip [ (n, t) | HsRecField n t _ <- fields ] - + field_names = map cd_fld_name fields + btys = map cd_fld_type fields } tcResultType :: TyCon @@ -1001,6 +1047,9 @@ checkNewDataCon con -- Return type is (T a b c) ; checkTc (null ex_tvs && null theta) (newtypeExError con) -- No existentials + ; checkTc (not (any isMarkedStrict (dataConStrictMarks con))) + (newtypeStrictError con) + -- No strictness } where (_univ_tvs, ex_tvs, eq_spec, theta, arg_tys, _res_ty) = dataConFullSig con @@ -1010,10 +1059,13 @@ checkValidClass :: Class -> TcM () checkValidClass cls = do { -- CHECK ARITY 1 FOR HASKELL 1.4 gla_exts <- doptM Opt_GlasgowExts + ; multi_param_type_classes <- doptM Opt_MultiParamTypeClasses + ; fundep_classes <- doptM Opt_FunctionalDependencies -- Check that the class is unary, unless GlaExs ; checkTc (notNull tyvars) (nullaryClassErr cls) - ; checkTc (gla_exts || unary) (classArityErr cls) + ; checkTc (multi_param_type_classes || unary) (classArityErr cls) + ; checkTc (fundep_classes || null fundeps) (classFunDepsErr cls) -- Check the super-classes ; checkValidTheta (ClassSCCtxt (className cls)) theta @@ -1027,7 +1079,7 @@ checkValidClass cls ; checkTc (unary || no_generics) (genericMultiParamErr cls) } where - (tyvars, theta, _, op_stuff) = classBigSig cls + (tyvars, fundeps, theta, _, _, op_stuff) = classExtraBigSig cls unary = isSingleton tyvars no_generics = null [() | (_, GenDefMeth) <- op_stuff] @@ -1088,7 +1140,11 @@ nullaryClassErr cls classArityErr cls = vcat [ptext SLIT("Too many parameters for class") <+> quotes (ppr cls), - parens (ptext SLIT("Use -fglasgow-exts to allow multi-parameter classes"))] + parens (ptext SLIT("Use -XMultiParamTypeClasses to allow multi-parameter classes"))] + +classFunDepsErr cls + = vcat [ptext SLIT("Fundeps in class") <+> quotes (ppr cls), + parens (ptext SLIT("Use -XFunctionalDependencies to allow fundeps"))] noClassTyVarErr clas op = sep [ptext SLIT("The class method") <+> quotes (ppr op), @@ -1132,7 +1188,7 @@ badDataConTyCon data_con 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")) ] + , nest 2 (parens $ ptext SLIT("Use -X=GADT to allow GADTs")) ] badStupidTheta tc_name = ptext SLIT("A data type declared in GADT style cannot have a context:") <+> quotes (ppr tc_name) @@ -1145,6 +1201,10 @@ newtypeExError con = sep [ptext SLIT("A newtype constructor cannot have an existential context,"), nest 2 $ ptext SLIT("but") <+> quotes (ppr con) <+> ptext SLIT("does")] +newtypeStrictError con + = sep [ptext SLIT("A newtype constructor cannot have a strictness annotation,"), + nest 2 $ ptext SLIT("but") <+> quotes (ppr con) <+> ptext SLIT("does")] + newtypePredError con = sep [ptext SLIT("A newtype constructor must have a return type of form T a1 ... an"), nest 2 $ ptext SLIT("but") <+> quotes (ppr con) <+> ptext SLIT("does not")] @@ -1156,12 +1216,12 @@ newtypeFieldErr con_name n_flds badSigTyDecl tc_name = vcat [ ptext SLIT("Illegal kind signature") <+> quotes (ppr tc_name) - , nest 2 (parens $ ptext SLIT("Use -fglasgow-exts to allow kind signatures")) ] + , nest 2 (parens $ ptext SLIT("Use -XKindSignatures to allow kind signatures")) ] badFamInstDecl tc_name = vcat [ ptext SLIT("Illegal family instance for") <+> quotes (ppr tc_name) - , nest 2 (parens $ ptext SLIT("Use -findexed-types to allow indexed type families")) ] + , nest 2 (parens $ ptext SLIT("Use -X=TypeFamilies to allow indexed type families")) ] badGadtIdxTyDecl tc_name = vcat [ ptext SLIT("Illegal generalised algebraic data declaration for") <+> @@ -1183,11 +1243,20 @@ wrongKindOfFamily family = ptext SLIT("Wrong category of family instance; declaration was for a") <+> kindOfFamily where - kindOfFamily | isSynTyCon family = ptext SLIT("type synonym") - | isDataTyCon family = ptext SLIT("data type") - | isNewTyCon family = ptext SLIT("newtype") + kindOfFamily | isSynTyCon family = ptext SLIT("type synonym") + | isAlgTyCon family = ptext SLIT("data type") + | otherwise = pprPanic "wrongKindOfFamily" (ppr family) + +polyTyErr ty + = hang (ptext SLIT("Illegal polymorphic type in type instance") <> colon) 4 $ + ppr ty + +tyFamAppInIndexErr ty + = hang (ptext SLIT("Illegal type family application in type instance") <> + colon) 4 $ + ppr ty emptyConDeclsErr tycon = sep [quotes (ppr tycon) <+> ptext SLIT("has no constructors"), - nest 2 $ ptext SLIT("(-fglasgow-exts permits this)")] + nest 2 $ ptext SLIT("(-XEmptyDataDecls permits this)")] \end{code}