X-Git-Url: http://git.megacz.com/?p=ghc-hetmet.git;a=blobdiff_plain;f=compiler%2Ftypecheck%2FTcDeriv.lhs;h=4d1d448a24ad209fad447027bae61877f9d06488;hp=8fa8c0b3fa45c3b60535b51a5e3dd5d4fc5c9ea1;hb=a3bab0506498db41853543558c52a4fda0d183af;hpb=d2ce0f52d42edf32bb9f13796e6ba6edba8bd516 diff --git a/compiler/typecheck/TcDeriv.lhs b/compiler/typecheck/TcDeriv.lhs index 8fa8c0b..4d1d448 100644 --- a/compiler/typecheck/TcDeriv.lhs +++ b/compiler/typecheck/TcDeriv.lhs @@ -352,10 +352,8 @@ renameDeriv is_boot gen_binds insts rm_dups [] $ concat deriv_aux_binds aux_val_binds = ValBindsIn (listToBag aux_binds) aux_sigs ; rn_aux_lhs <- rnTopBindsLHS emptyFsEnv aux_val_binds - ; let aux_names = collectHsValBinders rn_aux_lhs - - ; bindLocalNames aux_names $ - do { (rn_aux, dus_aux) <- rnTopBindsRHS (mkNameSet aux_names) rn_aux_lhs + ; bindLocalNames (collectHsValBinders rn_aux_lhs) $ + do { (rn_aux, dus_aux) <- rnTopBindsRHS rn_aux_lhs ; (rn_inst_infos, fvs_insts) <- mapAndUnzipM rn_inst_info inst_infos ; return (rn_inst_infos, rn_aux `plusHsValBinds` rn_gen, dus_gen `plusDU` dus_aux `plusDU` usesOnly (plusFVs fvs_insts)) } } @@ -375,14 +373,14 @@ renameDeriv is_boot gen_binds insts , mkFVs (map dataConName (tyConDataCons tc))) -- See Note [Newtype deriving and unused constructors] - rn_inst_info (InstInfo { iSpec = inst, iBinds = VanillaInst binds sigs standalone_deriv }) + rn_inst_info inst_info@(InstInfo { iSpec = inst, iBinds = VanillaInst binds sigs standalone_deriv }) = -- Bring the right type variables into -- scope (yuk), and rename the method binds ASSERT( null sigs ) bindLocalNames (map Var.varName tyvars) $ do { (rn_binds, fvs) <- rnMethodBinds clas_nm (\_ -> []) [] binds ; let binds' = VanillaInst rn_binds [] standalone_deriv - ; return (InstInfo { iSpec = inst, iBinds = binds' }, fvs) } + ; return (inst_info { iBinds = binds' }, fvs) } where (tyvars,_, clas,_) = instanceHead inst clas_nm = className clas @@ -469,12 +467,13 @@ deriveStandalone (L loc (DerivDecl deriv_ty)) = setSrcSpan loc $ addErrCtxt (standaloneCtxt deriv_ty) $ do { traceTc "Standalone deriving decl for" (ppr deriv_ty) - ; (tvs, theta, tau) <- tcHsInstHead deriv_ty + ; (tvs, theta, cls, inst_tys) <- tcHsInstHead deriv_ty ; traceTc "Standalone deriving;" $ vcat [ text "tvs:" <+> ppr tvs , text "theta:" <+> ppr theta - , text "tau:" <+> ppr tau ] - ; (cls, inst_tys) <- checkValidInstance deriv_ty tvs theta tau + , text "cls:" <+> ppr cls + , text "tys:" <+> ppr inst_tys ] + ; checkValidInstance deriv_ty tvs theta cls inst_tys -- C.f. TcInstDcls.tcLocalInstDecl1 ; let cls_tys = take (length inst_tys - 1) inst_tys @@ -597,32 +596,46 @@ mkEqnHelp :: CtOrigin -> [TyVar] -> Class -> [Type] -> Type mkEqnHelp orig tvs cls cls_tys tc_app mtheta | Just (tycon, tc_args) <- tcSplitTyConApp_maybe tc_app , isAlgTyCon tycon -- Check for functions, primitive types etc - = do { (rep_tc, rep_tc_args) <- tcLookupDataFamInst tycon tc_args - -- Be careful to test rep_tc here: in the case of families, - -- we want to check the instance tycon, not the family tycon - - -- For standalone deriving (mtheta /= Nothing), - -- check that all the data constructors are in scope. - -- No need for this when deriving Typeable, becuase we don't need - -- the constructors for that. - ; rdr_env <- getGlobalRdrEnv - ; let hidden_data_cons = isAbstractTyCon rep_tc || any not_in_scope (tyConDataCons rep_tc) - not_in_scope dc = null (lookupGRE_Name rdr_env (dataConName dc)) - ; checkTc (isNothing mtheta || - not hidden_data_cons || - className cls `elem` typeableClassNames) - (derivingHiddenErr tycon) - - ; dflags <- getDOpts - ; if isDataTyCon rep_tc then - mkDataTypeEqn orig dflags tvs cls cls_tys - tycon tc_args rep_tc rep_tc_args mtheta - else - mkNewTypeEqn orig dflags tvs cls cls_tys - tycon tc_args rep_tc rep_tc_args mtheta } + = mk_alg_eqn tycon tc_args | otherwise = failWithTc (derivingThingErr False cls cls_tys tc_app (ptext (sLit "The last argument of the instance must be a data or newtype application"))) + + where + bale_out msg = failWithTc (derivingThingErr False cls cls_tys tc_app msg) + + mk_alg_eqn tycon tc_args + | className cls `elem` typeableClassNames + = do { dflags <- getDOpts + ; case checkTypeableConditions (dflags, tycon) of + Just err -> bale_out err + Nothing -> mk_typeable_eqn orig tvs cls tycon tc_args mtheta } + + | isDataFamilyTyCon tycon + , length tc_args /= tyConArity tycon + = bale_out (ptext (sLit "Unsaturated data family application")) + + | otherwise + = do { (rep_tc, rep_tc_args) <- tcLookupDataFamInst tycon tc_args + -- Be careful to test rep_tc here: in the case of families, + -- we want to check the instance tycon, not the family tycon + + -- For standalone deriving (mtheta /= Nothing), + -- check that all the data constructors are in scope. + ; rdr_env <- getGlobalRdrEnv + ; let hidden_data_cons = isAbstractTyCon rep_tc || + any not_in_scope (tyConDataCons rep_tc) + not_in_scope dc = null (lookupGRE_Name rdr_env (dataConName dc)) + ; unless (isNothing mtheta || not hidden_data_cons) + (bale_out (derivingHiddenErr tycon)) + + ; dflags <- getDOpts + ; if isDataTyCon rep_tc then + mkDataTypeEqn orig dflags tvs cls cls_tys + tycon tc_args rep_tc rep_tc_args mtheta + else + mkNewTypeEqn orig dflags tvs cls cls_tys + tycon tc_args rep_tc rep_tc_args mtheta } \end{code} @@ -657,15 +670,10 @@ mkDataTypeEqn orig dflags tvs cls cls_tys go_for_it = mk_data_eqn orig tvs cls tycon tc_args rep_tc rep_tc_args mtheta bale_out msg = failWithTc (derivingThingErr False cls cls_tys (mkTyConApp tycon tc_args) msg) -mk_data_eqn, mk_typeable_eqn - :: CtOrigin -> [TyVar] -> Class - -> TyCon -> [TcType] -> TyCon -> [TcType] -> DerivContext - -> TcM EarlyDerivSpec +mk_data_eqn :: CtOrigin -> [TyVar] -> Class + -> TyCon -> [TcType] -> TyCon -> [TcType] -> DerivContext + -> TcM EarlyDerivSpec mk_data_eqn orig tvs cls tycon tc_args rep_tc rep_tc_args mtheta - | getName cls `elem` typeableClassNames - = mk_typeable_eqn orig tvs cls tycon tc_args rep_tc rep_tc_args mtheta - - | otherwise = do { dfun_name <- new_dfun_name cls tycon ; loc <- getSrcSpanM ; let inst_tys = [mkTyConApp tycon tc_args] @@ -680,7 +688,11 @@ mk_data_eqn orig tvs cls tycon tc_args rep_tc rep_tc_args mtheta ; return (if isJust mtheta then Right spec -- Specified context else Left spec) } -- Infer context -mk_typeable_eqn orig tvs cls tycon tc_args rep_tc rep_tc_args mtheta +---------------------- +mk_typeable_eqn :: CtOrigin -> [TyVar] -> Class + -> TyCon -> [TcType] -> DerivContext + -> TcM EarlyDerivSpec +mk_typeable_eqn orig tvs cls tycon tc_args mtheta -- The Typeable class is special in several ways -- data T a b = ... deriving( Typeable ) -- gives @@ -694,7 +706,7 @@ mk_typeable_eqn orig tvs cls tycon tc_args rep_tc rep_tc_args mtheta = do { checkTc (cls `hasKey` typeableClassKey) (ptext (sLit "Use deriving( Typeable ) on a data type declaration")) ; real_cls <- tcLookupClass (typeableClassNames !! tyConArity tycon) - ; mk_typeable_eqn orig tvs real_cls tycon [] rep_tc [] (Just []) } + ; mk_typeable_eqn orig tvs real_cls tycon [] (Just []) } | otherwise -- standaone deriving = do { checkTc (null tc_args) @@ -705,10 +717,10 @@ mk_typeable_eqn orig tvs cls tycon tc_args rep_tc rep_tc_args mtheta ; return (Right $ DS { ds_loc = loc, ds_orig = orig, ds_name = dfun_name, ds_tvs = [] , ds_cls = cls, ds_tys = [mkTyConApp tycon []] - , ds_tc = rep_tc, ds_tc_args = rep_tc_args + , ds_tc = tycon, ds_tc_args = [] , ds_theta = mtheta `orElse` [], ds_newtype = False }) } - +---------------------- inferConstraints :: [TyVar] -> Class -> [TcType] -> TyCon -> [TcType] -> ThetaType -- Generate a sufficiently large set of constraints that typechecking the -- generated method definitions should succeed. This set will be simplified @@ -794,6 +806,9 @@ checkSideConditions dflags mtheta cls cls_tys rep_tc where ty_args_why = quotes (ppr (mkClassPred cls cls_tys)) <+> ptext (sLit "is not a class") +checkTypeableConditions :: Condition +checkTypeableConditions = checkFlag Opt_DeriveDataTypeable `andCond` cond_typeableOK + nonStdErr :: Class -> SDoc nonStdErr cls = quotes (ppr cls) <+> ptext (sLit "is not a derivable class") @@ -814,7 +829,6 @@ sideConditions mtheta cls cond_functorOK False) -- Functor/Fold/Trav works ok for rank-n types | cls_key == traversableClassKey = Just (checkFlag Opt_DeriveTraversable `andCond` cond_functorOK False) - | getName cls `elem` typeableClassNames = Just (checkFlag Opt_DeriveDataTypeable `andCond` cond_typeableOK) | otherwise = Nothing where cls_key = getUnique cls @@ -830,11 +844,11 @@ type Condition = (DynFlags, TyCon) -> Maybe SDoc orCond :: Condition -> Condition -> Condition orCond c1 c2 tc = case c1 tc of - Nothing -> Nothing -- c1 succeeds - Just x -> case c2 tc of -- c1 fails + Nothing -> Nothing -- c1 succeeds + Just x -> case c2 tc of -- c1 fails Nothing -> Nothing Just y -> Just (x $$ ptext (sLit " and") $$ y) - -- Both fail + -- Both fail andCond :: Condition -> Condition -> Condition andCond c1 c2 tc = case c1 tc of @@ -845,16 +859,14 @@ cond_stdOK :: DerivContext -> Condition cond_stdOK (Just _) _ = Nothing -- Don't check these conservative conditions for -- standalone deriving; just generate the code + -- and let the typechecker handle the result cond_stdOK Nothing (_, rep_tc) - | null data_cons = Just (no_cons_why $$ suggestion) + | null data_cons = Just (no_cons_why rep_tc $$ suggestion) | not (null con_whys) = Just (vcat con_whys $$ suggestion) | otherwise = Nothing where suggestion = ptext (sLit "Possible fix: use a standalone deriving declaration instead") data_cons = tyConDataCons rep_tc - no_cons_why = quotes (pprSourceTyCon rep_tc) <+> - ptext (sLit "has no data constructors") - con_whys = mapCatMaybes check_con data_cons check_con :: DataCon -> Maybe SDoc @@ -863,6 +875,10 @@ cond_stdOK Nothing (_, rep_tc) , all isTauTy (dataConOrigArgTys con) = Nothing | otherwise = Just (badCon con (ptext (sLit "does not have a Haskell-98 type"))) +no_cons_why :: TyCon -> SDoc +no_cons_why rep_tc = quotes (pprSourceTyCon rep_tc) <+> + ptext (sLit "has no data constructors") + cond_enumOrProduct :: Condition cond_enumOrProduct = cond_isEnumeration `orCond` (cond_isProduct `andCond` cond_noUnliftedArgs) @@ -880,11 +896,13 @@ cond_noUnliftedArgs (_, tc) cond_isEnumeration :: Condition cond_isEnumeration (_, rep_tc) - | isEnumerationTyCon rep_tc = Nothing - | otherwise = Just why + | isEnumerationTyCon rep_tc = Nothing + | otherwise = Just why where - why = quotes (pprSourceTyCon rep_tc) <+> - ptext (sLit "has non-nullary constructors") + why = sep [ quotes (pprSourceTyCon rep_tc) <+> + ptext (sLit "is not an enumeration type") + , nest 2 $ ptext (sLit "(an enumeration consists of one or more nullary constructors)") ] + -- See Note [Enumeration types] in TyCon cond_isProduct :: Condition cond_isProduct (_, rep_tc) @@ -892,26 +910,22 @@ cond_isProduct (_, rep_tc) | otherwise = Just why where why = quotes (pprSourceTyCon rep_tc) <+> - ptext (sLit "has more than one constructor") + ptext (sLit "does not have precisely one constructor") cond_typeableOK :: Condition -- OK for Typeable class -- Currently: (a) args all of kind * -- (b) 7 or fewer args -cond_typeableOK (_, rep_tc) - | tyConArity rep_tc > 7 = Just too_many - | not (all (isSubArgTypeKind . tyVarKind) (tyConTyVars rep_tc)) - = Just bad_kind - | isFamInstTyCon rep_tc = Just fam_inst -- no Typable for family insts - | otherwise = Nothing +cond_typeableOK (_, tc) + | tyConArity tc > 7 = Just too_many + | not (all (isSubArgTypeKind . tyVarKind) (tyConTyVars tc)) + = Just bad_kind + | otherwise = Nothing where - too_many = quotes (pprSourceTyCon rep_tc) <+> + too_many = quotes (pprSourceTyCon tc) <+> ptext (sLit "has too many arguments") - bad_kind = quotes (pprSourceTyCon rep_tc) <+> + bad_kind = quotes (pprSourceTyCon tc) <+> ptext (sLit "has arguments of kind other than `*'") - fam_inst = quotes (pprSourceTyCon rep_tc) <+> - ptext (sLit "is a type family") - functorLikeClassKeys :: [Unique] functorLikeClassKeys = [functorClassKey, foldableClassKey, traversableClassKey] @@ -923,10 +937,7 @@ cond_functorOK :: Bool -> Condition -- (c) don't use argument in the wrong place, e.g. data T a = T (X a a) -- (d) optionally: don't use function types -- (e) no "stupid context" on data type -cond_functorOK allowFunctions (dflags, rep_tc) - | not (dopt Opt_DeriveFunctor dflags) - = Just (ptext (sLit "You need -XDeriveFunctor to derive an instance for this class")) - +cond_functorOK allowFunctions (_, rep_tc) | null tc_tvs = Just (ptext (sLit "Data type") <+> quotes (ppr rep_tc) <+> ptext (sLit "has no parameters")) @@ -967,7 +978,7 @@ cond_functorOK allowFunctions (dflags, rep_tc) checkFlag :: ExtensionFlag -> Condition checkFlag flag (dflags, _) - | dopt flag dflags = Nothing + | xopt flag dflags = Nothing | otherwise = Just why where why = ptext (sLit "You need -X") <> text flag_str @@ -1070,7 +1081,7 @@ mkNewTypeEqn orig dflags tvs | can_derive_via_isomorphism -> bale_out (non_std $$ suggest_nd) -- Try newtype deriving! | otherwise -> bale_out non_std where - newtype_deriving = dopt Opt_GeneralizedNewtypeDeriving dflags + newtype_deriving = xopt Opt_GeneralizedNewtypeDeriving dflags go_for_it = mk_data_eqn orig tvs cls tycon tc_args rep_tycon rep_tc_args mtheta bale_out msg = failWithTc (derivingThingErr newtype_deriving cls cls_tys inst_ty msg) @@ -1390,26 +1401,26 @@ the renamer. What a great hack! genInst :: Bool -- True <=> standalone deriving -> OverlapFlag -> DerivSpec -> TcM (InstInfo RdrName, DerivAuxBinds) -genInst standalone_deriv oflag spec - | ds_newtype spec - = return (InstInfo { iSpec = mkInstance oflag (ds_theta spec) spec - , iBinds = NewTypeDerived co rep_tycon }, []) +genInst standalone_deriv oflag + spec@(DS { ds_tc = rep_tycon, ds_tc_args = rep_tc_args + , ds_theta = theta, ds_newtype = is_newtype + , ds_name = name, ds_cls = clas }) + | is_newtype + = return (InstInfo { iSpec = inst_spec + , iBinds = NewTypeDerived co rep_tycon }, []) | otherwise - = do { let loc = getSrcSpan (ds_name spec) - inst = mkInstance oflag (ds_theta spec) spec - clas = ds_cls spec - - -- In case of a family instance, we need to use the representation - -- tycon (after all, it has the data constructors) - ; fix_env <- getFixityEnv - ; let (meth_binds, aux_binds) = genDerivBinds loc fix_env clas rep_tycon - binds = VanillaInst meth_binds [] standalone_deriv - ; return (InstInfo { iSpec = inst, iBinds = binds }, aux_binds) - } + = do { fix_env <- getFixityEnv + ; let loc = getSrcSpan name + (meth_binds, aux_binds) = genDerivBinds loc fix_env clas rep_tycon + -- In case of a family instance, we need to use the representation + -- tycon (after all, it has the data constructors) + + ; return (InstInfo { iSpec = inst_spec + , iBinds = VanillaInst meth_binds [] standalone_deriv } + , aux_binds) } where - rep_tycon = ds_tc spec - rep_tc_args = ds_tc_args spec + inst_spec = mkInstance oflag theta spec co1 = case tyConFamilyCoercion_maybe rep_tycon of Just co_con -> ACo (mkTyConApp co_con rep_tc_args) Nothing -> id_co