X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=compiler%2Ftypecheck%2FTcTyClsDecls.lhs;h=89afedfda8ea757cf3f95eadc40de2bea19bac76;hb=b25d67d4c0398dbceca0165c3b43df0625e1e06a;hp=863cd6df1fc06ee0302d876ef9fc03fa37817648;hpb=5822cb8d13aa3c05d2b46b4510c13d94b902eb21;p=ghc-hetmet.git diff --git a/compiler/typecheck/TcTyClsDecls.lhs b/compiler/typecheck/TcTyClsDecls.lhs index 863cd6d..89afedf 100644 --- a/compiler/typecheck/TcTyClsDecls.lhs +++ b/compiler/typecheck/TcTyClsDecls.lhs @@ -6,6 +6,13 @@ TcTyClsDecls: Typecheck type and class declarations \begin{code} +{-# OPTIONS -w #-} +-- The above warning supression flag is a temporary kludge. +-- While working on this module you are encouraged to remove it and fix +-- any warnings in the module. See +-- http://hackage.haskell.org/trac/ghc/wiki/Commentary/CodingStyle#Warnings +-- for details + module TcTyClsDecls ( tcTyAndClassDecls, tcFamInstDecl ) where @@ -133,8 +140,12 @@ indeed type families). I think. tcTyAndClassDecls :: ModDetails -> [LTyClDecl Name] -> TcM TcGblEnv -- Input env extended by types and classes -- and their implicit Ids,DataCons +-- Fails if there are any errors + tcTyAndClassDecls boot_details allDecls - = do { -- Omit instances of type families; they are handled together + = checkNoErrs $ -- The code recovers internally, but if anything gave rise to + -- an error we'd better stop now, to avoid a cascade + do { -- Omit instances of type families; they are handled together -- with the *heads* of class instances ; let decls = filter (not . isFamInstDecl . unLoc) allDecls @@ -240,7 +251,7 @@ tcFamInstDecl (L loc decl) recoverM (returnM Nothing) $ setSrcSpan loc $ tcAddDeclCtxt decl $ - do { -- type families require -ftype-families and can't be in an + do { -- type families require -XTypeFamilies and can't be in an -- hs-boot file ; type_families <- doptM Opt_TypeFamilies ; is_boot <- tcIsHsBoot -- Are we compiling an hs-boot file? @@ -275,13 +286,8 @@ tcFamInstDecl1 (decl@TySynonym {tcdLName = L loc tc_name}) ; t_rhs <- tcHsKindedType k_rhs -- (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) + -- - check the well-formedness of the instance + ; checkValidTypeInst t_typats t_rhs -- (4) construct representation tycon ; rep_tc_name <- newFamInstTyConName tc_name loc @@ -317,7 +323,8 @@ tcFamInstDecl1 (decl@TyData {tcdND = new_or_data, tcdLName = L loc tc_name, -- (3) Check that -- - left-hand side contains no type family applications - -- (vanilla synonyms are fine, though) + -- (vanilla synonyms are fine, though, and we checked for + -- foralls earlier) ; mappM_ checkTyFamFreeness t_typats -- - we don't use GADT syntax for indexed types @@ -329,8 +336,9 @@ tcFamInstDecl1 (decl@TyData {tcdND = new_or_data, tcdLName = L loc tc_name, -- (4) construct representation tycon ; rep_tc_name <- newFamInstTyConName tc_name loc + ; let ex_ok = True -- Existentials ok for type families! ; tycon <- fixM (\ tycon -> do - { data_cons <- mappM (addLocM (tcConDecl unbox_strict tycon t_tvs)) + { data_cons <- mappM (addLocM (tcConDecl unbox_strict ex_ok tycon t_tvs)) k_cons ; tc_rhs <- case new_or_data of @@ -354,27 +362,6 @@ 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 -- - @@ -684,14 +671,14 @@ tcTyClDecl1 _calc_isrec { traceTc (text "type family: " <+> ppr tc_name) ; idx_tys <- doptM Opt_TypeFamilies - -- Check that we don't use families without -ftype-families + -- Check that we don't use families without -XTypeFamilies ; checkTc idx_tys $ badFamInstDecl tc_name ; tycon <- buildSynTyCon tc_name tvs' (OpenSynTyCon kind Nothing) Nothing ; return [ATyCon tycon] } - -- "newtype family" or "data family" declaration + -- "data family" declaration tcTyClDecl1 _calc_isrec (TyFamily {tcdFlavour = DataFamily, tcdLName = L _ tc_name, tcdTyVars = tvs, tcdKind = mb_kind}) @@ -702,7 +689,7 @@ tcTyClDecl1 _calc_isrec ; idx_tys <- doptM Opt_TypeFamilies - -- Check that we don't use families without -ftype-families + -- Check that we don't use families without -XTypeFamilies ; checkTc idx_tys $ badFamInstDecl tc_name ; tycon <- buildAlgTyCon tc_name final_tvs [] @@ -711,6 +698,7 @@ tcTyClDecl1 _calc_isrec } -- "newtype" and "data" + -- NB: not used for newtype/data instances (whether associated or not) tcTyClDecl1 calc_isrec (TyData {tcdND = new_or_data, tcdCtxt = ctxt, tcdTyVars = tvs, tcdLName = L _ tc_name, tcdKindSig = mb_ksig, tcdCons = cons}) @@ -722,8 +710,10 @@ tcTyClDecl1 calc_isrec ; unbox_strict <- doptM Opt_UnboxStrictFields ; empty_data_decls <- doptM Opt_EmptyDataDecls ; kind_signatures <- doptM Opt_KindSignatures + ; existential_ok <- doptM Opt_ExistentialQuantification ; gadt_ok <- doptM Opt_GADTs ; is_boot <- tcIsHsBoot -- Are we compiling an hs-boot file? + ; let ex_ok = existential_ok || gadt_ok -- Data cons can have existential context -- Check that we don't use GADT syntax in H98 world ; checkTc (gadt_ok || h98_syntax) (badGadtDecl tc_name) @@ -744,7 +734,7 @@ tcTyClDecl1 calc_isrec (newtypeConError tc_name (length cons)) ; tycon <- fixM (\ tycon -> do - { data_cons <- mappM (addLocM (tcConDecl unbox_strict tycon final_tvs)) + { data_cons <- mappM (addLocM (tcConDecl unbox_strict ex_ok tycon final_tvs)) cons ; tc_rhs <- if null cons && is_boot -- In a hs-boot file, empty cons means @@ -773,6 +763,8 @@ tcTyClDecl1 calc_isrec { ctxt' <- tcHsKindedContext ctxt ; fds' <- mappM (addLocM tc_fundep) fundeps ; atss <- mappM (addLocM (tcTyClDecl1 (const Recursive))) ats + -- NB: 'ats' only contains "type family" and "data family" + -- declarations as well as type family defaults ; let ats' = zipWith setTyThingPoss atss (map (tcdTyVars . unLoc) ats) ; sig_stuff <- tcClassSigs class_name sigs meths ; clas <- fixM (\ clas -> @@ -813,14 +805,17 @@ tcTyClDecl1 calc_isrec ----------------------------------- tcConDecl :: Bool -- True <=> -funbox-strict_fields + -> Bool -- True <=> -XExistentialQuantificaton or -XGADTs -> TyCon -> [TyVar] -> ConDecl Name -> TcM DataCon -tcConDecl unbox_strict tycon tc_tvs -- Data types +tcConDecl unbox_strict existential_ok tycon tc_tvs -- Data types (ConDecl name _ tvs ctxt details res_ty _) = tcTyVarBndrs tvs $ \ tvs' -> do { ctxt' <- tcHsKindedContext ctxt + ; checkTc (existential_ok || (null tvs && null (unLoc ctxt))) + (badExistential name) ; (univ_tvs, ex_tvs, eq_preds, data_tc) <- tcResultType tycon tc_tvs tvs' res_ty ; let -- Tiresome: tidy the tyvar binders, since tc_tvs and tvs' may have the same OccNames @@ -1059,6 +1054,9 @@ checkValidDataCon tc con addErrCtxt (dataConCtxt con) $ do { checkTc (dataConTyCon con == tc) (badDataConTyCon con) ; checkValidType ctxt (dataConUserType con) + ; checkValidMonoType (dataConOrigResTy con) + -- Disallow MkT :: T (forall a. a->a) + -- Reason: it's really the argument of an equality constraint ; ifM (isNewTyCon tc) (checkNewDataCon con) } where @@ -1217,6 +1215,11 @@ badGadtDecl tc_name = vcat [ ptext SLIT("Illegal generalised algebraic data declaration for") <+> quotes (ppr tc_name) , nest 2 (parens $ ptext SLIT("Use -XGADTs to allow GADTs")) ] +badExistential con_name + = hang (ptext SLIT("Data constructor") <+> quotes (ppr con_name) <+> + ptext SLIT("has existential type variables, or a context")) + 2 (parens $ ptext SLIT("Use -XExistentialQuantification or -XGADTs to allow this")) + badStupidTheta tc_name = ptext SLIT("A data type declared in GADT style cannot have a context:") <+> quotes (ppr tc_name) @@ -1278,15 +1281,6 @@ wrongKindOfFamily family = | 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("(-XEmptyDataDecls permits this)")]