X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=compiler%2Ftypecheck%2FTcTyClsDecls.lhs;h=12fb28d7aecd70ca0dfdde36cf238fc24aa6d173;hb=4c6a3f787abcaed009a574196d82237d9ae64fc8;hp=76b9a9ee40e41a92538b31b5f5d556f04bca0348;hpb=a1632b0af860d28589b444d8e28896bee8bced38;p=ghc-hetmet.git diff --git a/compiler/typecheck/TcTyClsDecls.lhs b/compiler/typecheck/TcTyClsDecls.lhs index 76b9a9e..12fb28d 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 @@ -17,6 +24,7 @@ import HsTypes import BasicTypes import HscTypes import BuildTyCl +import TcUnify import TcRnMonad import TcEnv import TcTyDecls @@ -43,8 +51,9 @@ import SrcLoc import ListSetOps import Digraph import DynFlags +import FastString -import Data.List ( partition, elemIndex ) +import Data.List import Control.Monad ( mplus ) \end{code} @@ -132,8 +141,12 @@ 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 indexed types; 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 @@ -174,7 +187,7 @@ tcTyAndClassDecls boot_details allDecls ; tcExtendGlobalEnv syn_tycons $ do -- Type-check the data types and classes - { alg_tyclss <- mappM tc_decl kc_alg_decls + { alg_tyclss <- mapM tc_decl kc_alg_decls ; return (syn_tycons, concat alg_tyclss) }}}) -- Finished with knot-tying now @@ -183,7 +196,7 @@ tcTyAndClassDecls boot_details allDecls -- Perform the validity check { traceTc (text "ready for validity check") - ; mappM_ (addLocM checkValidTyCl) decls + ; mapM_ (addLocM checkValidTyCl) decls ; traceTc (text "done") -- Add the implicit things; @@ -236,14 +249,14 @@ GADTs). tcFamInstDecl :: LTyClDecl Name -> TcM (Maybe TyThing) -- Nothing if error tcFamInstDecl (L loc decl) = -- Prime error recovery, set source location - recoverM (returnM Nothing) $ + recoverM (return Nothing) $ setSrcSpan loc $ tcAddDeclCtxt decl $ - do { -- type families require -findexed-types and can't be in an + do { -- type families require -XTypeFamilies and can't be in an -- hs-boot file - ; gla_exts <- doptM Opt_IndexedTypes + ; type_families <- doptM Opt_TypeFamilies ; is_boot <- tcIsHsBoot -- Are we compiling an hs-boot file? - ; checkTc gla_exts $ badFamInstDecl (tcdLName decl) + ; checkTc type_families $ badFamInstDecl (tcdLName decl) ; checkTc (not is_boot) $ badBootFamInstDeclErr -- perform kind and type checking @@ -259,16 +272,26 @@ tcFamInstDecl1 (decl@TySynonym {tcdLName = L loc tc_name}) 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 + -- we need the exact same number of type parameters as the family + -- declaration + ; let famArity = tyConArity family + ; checkTc (length k_typats == famArity) $ + wrongNumberOfParmsErr famArity + -- (2) type check type equation ; tcTyVarBndrs k_tvs $ \t_tvs -> do { -- turn kinded into proper tyvars - ; t_typats <- mappM tcHsKindedType k_typats + ; t_typats <- mapM tcHsKindedType k_typats ; t_rhs <- tcHsKindedType k_rhs - -- (3) construct representation tycon - ; rep_tc_name <- newFamInstTyConName tc_name (srcSpanStart loc) + -- (3) check that + -- - check the well-formedness of the instance + ; checkValidTypeInst t_typats 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)) @@ -280,8 +303,7 @@ 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 @@ -290,32 +312,40 @@ tcFamInstDecl1 (decl@TyData {tcdND = new_or_data, tcdLName = L loc tc_name, k_cons = tcdCons k_decl -- result kind must be '*' (otherwise, we have too few patterns) - ; checkTc (isLiftedTypeKind resKind) $ tooFewParmsErr tc_name + ; checkTc (isLiftedTypeKind resKind) $ tooFewParmsErr (tyConArity family) -- (2) type check indexed data type declaration ; 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 <- mapM tcHsKindedType k_typats + ; stupid_theta <- tcHsKindedContext k_ctxt + + -- (3) Check that + -- - left-hand side contains no type family applications + -- (vanilla synonyms are fine, though, and we checked for + -- foralls earlier) + ; mapM_ 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 - - -- (3) construct representation tycon - ; rep_tc_name <- newFamInstTyConName tc_name (srcSpanStart loc) + -- (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 <- mapM (addLocM (tcConDecl unbox_strict ex_ok 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) + NewType -> ASSERT( not (null 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? @@ -340,7 +370,7 @@ 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) @@ -358,7 +388,7 @@ kcIdxTyPats decl thing_inside -- type functions can have a higher-kinded result ; let resultKind = mkArrowKinds (drop (length hs_typats) kinds) resKind - ; typats <- TcRnMonad.zipWithM kcCheckHsType hs_typats kinds + ; typats <- zipWithM kcCheckHsType hs_typats kinds ; thing_inside tvs typats resultKind family } where @@ -393,7 +423,7 @@ 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'. @@ -410,7 +440,7 @@ kcTyClDecls syn_decls 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 + ; alg_kinds <- mapM getInitialKind initialKindDecls ; tcExtendKindEnv alg_kinds $ do -- Now kind-check the type synonyms, in dependency order @@ -426,7 +456,7 @@ kcTyClDecls syn_decls alg_decls -- 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) + { kc_alg_decls <- mapM (wrapLocM kcTyClDecl) (filter (not . isFamInstDecl . unLoc) alg_decls) ; return (kc_syn_decls, kc_alg_decls) }}} @@ -500,18 +530,15 @@ kcTyClDecl decl@(TyData {}) kcTyClDeclBody decl $ kcDataDecl decl -kcTyClDecl decl@(TyFamily {tcdKind = kind}) - = kcTyClDeclBody decl $ \ tvs' -> - return (decl {tcdTyVars = tvs', - tcdKind = kind `mplus` Just liftedTypeKind}) - -- default result kind is '*' +kcTyClDecl decl@(TyFamily {}) + = kcFamilyDecl [] decl -- the empty list signals a toplevel decl kcTyClDecl decl@(ClassDecl {tcdCtxt = ctxt, tcdSigs = sigs, tcdATs = ats}) = kcTyClDeclBody decl $ \ tvs' -> do { is_boot <- tcIsHsBoot ; ctxt' <- kcHsContext ctxt - ; ats' <- mappM (wrapLocM kcTyClDecl) ats - ; sigs' <- mappM (wrapLocM kc_sig ) sigs + ; ats' <- mapM (wrapLocM (kcFamilyDecl tvs')) ats + ; sigs' <- mapM (wrapLocM kc_sig) sigs ; return (decl {tcdTyVars = tvs', tcdCtxt = ctxt', tcdSigs = sigs', tcdATs = ats'}) } where @@ -549,7 +576,7 @@ 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 + ; cons' <- mapM (wrapLocM kc_con_decl) cons ; return (decl {tcdTyVars = tvs, tcdCtxt = ctxt', tcdCons = cons'}) } where -- doc comments are typechecked to Nothing here @@ -563,13 +590,18 @@ kcDataDecl decl@(TyData {tcdND = new_or_data, tcdCtxt = ctxt, tcdCons = cons}) return (ConDecl name expl ex_tvs' ex_ctxt' details' res' Nothing) kc_con_details (PrefixCon btys) - = do { btys' <- mappM kc_larg_ty btys ; return (PrefixCon btys') } + = do { btys' <- mapM 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') } + = 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') } + = do { fields' <- mapM 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 @@ -577,6 +609,25 @@ kcDataDecl decl@(TyData {tcdND = new_or_data, tcdCtxt = ctxt, tcdCons = cons}) -- 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 + +-- Kind check a family declaration or type family default declaration. +-- +kcFamilyDecl :: [LHsTyVarBndr Name] -- tyvars of enclosing class decl if any + -> TyClDecl Name -> TcM (TyClDecl Name) +kcFamilyDecl classTvs decl@(TyFamily {tcdKind = kind}) + = kcTyClDeclBody decl $ \tvs' -> + do { mapM_ unifyClassParmKinds tvs' + ; return (decl {tcdTyVars = tvs', + tcdKind = kind `mplus` Just liftedTypeKind}) + -- default result kind is '*' + } + where + unifyClassParmKinds (L _ (KindedTyVar n k)) + | Just classParmKind <- lookup n classTyKinds = unifyKind k classParmKind + | otherwise = return () + classTyKinds = [(n, k) | L _ (KindedTyVar n k) <- classTvs] +kcFamilyDecl _ decl@(TySynonym {}) -- type family defaults + = panic "TcTyClsDecls.kcFamilyDecl: not implemented yet" \end{code} @@ -619,38 +670,36 @@ 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 -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 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 -XTypeFamilies ; 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" 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}) @@ -660,29 +709,35 @@ 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 + ; 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 (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) - (emptyConDeclsErr tc_name) - -- Check that a newtype has exactly one constructor + -- Do this before checking for empty data decls, so that + -- we don't suggest -XEmptyDataDecls for newtypes ; checkTc (new_or_data == DataType || isSingleton cons) (newtypeConError tc_name (length cons)) + -- Check that there's at least one condecl, + -- or else we're reading an hs-boot file, or -XEmptyDataDecls + ; checkTc (not (null cons) || empty_data_decls || is_boot) + (emptyConDeclsErr tc_name) + ; tycon <- fixM (\ tycon -> do - { data_cons <- mappM (addLocM (tcConDecl unbox_strict tycon final_tvs)) + { data_cons <- mapM (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 @@ -690,7 +745,7 @@ tcTyClDecl1 calc_isrec else case new_or_data of DataType -> return (mkDataTyConRhs data_cons) NewType -> - ASSERT( isSingleton data_cons ) + ASSERT( not (null data_cons) ) mkNewTyConRhs tc_name tycon (head data_cons) ; buildAlgTyCon tc_name final_tvs stupid_theta tc_rhs is_rec (want_generic && canDoGenerics data_cons) h98_syntax Nothing @@ -709,8 +764,10 @@ tcTyClDecl1 calc_isrec tcdFDs = fundeps, tcdSigs = sigs, tcdATs = ats} ) = tcTyVarBndrs tvs $ \ tvs' -> do { ctxt' <- tcHsKindedContext ctxt - ; fds' <- mappM (addLocM tc_fundep) fundeps - ; atss <- mappM (addLocM (tcTyClDecl1 (const Recursive))) ats + ; fds' <- mapM (addLocM tc_fundep) fundeps + ; atss <- mapM (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 -> @@ -720,15 +777,16 @@ tcTyClDecl1 calc_isrec tycon_name = tyConName (classTyCon clas) tc_isrec = calc_isrec tycon_name in - buildClass class_name tvs' ctxt' fds' ats' + buildClass False {- Must include unfoldings for selectors -} + class_name tvs' ctxt' fds' ats' sig_stuff tc_isrec) ; return (AClass clas : ats') -- NB: Order is important due to the call to `mkGlobalThings' when -- tying the the type and class declaration type checking knot. } where - tc_fundep (tvs1, tvs2) = do { tvs1' <- mappM tcLookupTyVar tvs1 ; - ; tvs2' <- mappM tcLookupTyVar tvs2 ; + tc_fundep (tvs1, tvs2) = do { tvs1' <- mapM tcLookupTyVar tvs1 ; + ; tvs2' <- mapM tcLookupTyVar tvs2 ; ; return (tvs1', tvs2') } -- For each AT argument compute the position of the corresponding class @@ -747,24 +805,28 @@ tcTyClDecl1 calc_isrec tcTyClDecl1 calc_isrec (ForeignType {tcdLName = L _ tc_name, tcdExtName = tc_ext_name}) - = returnM [ATyCon (mkForeignTyCon tc_name tc_ext_name liftedTypeKind 0)] + = return [ATyCon (mkForeignTyCon tc_name tc_ext_name liftedTypeKind 0)] ----------------------------------- 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 + = addErrCtxt (dataConCtxt name) $ + 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 tc_datacon is_infix field_lbls btys = do { let bangs = map getBangStrictness btys - ; arg_tys <- mappM tcHsBangType btys + ; arg_tys <- mapM tcHsBangType btys ; buildDataCon (unLoc name) is_infix (argStrictness unbox_strict bangs arg_tys) (map unLoc field_lbls) @@ -779,8 +841,8 @@ 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 @@ -896,7 +958,7 @@ checkCycleErrs tyclss | null cls_cycles = return () | otherwise - = do { mappM_ recClsErr cls_cycles + = do { mapM_ recClsErr cls_cycles ; failM } -- Give up now, because later checkValidTyCl -- will loop if the synonym is recursive where @@ -930,14 +992,14 @@ checkValidTyCon tc OpenSynTyCon _ _ -> return () SynonymTyCon ty -> checkValidType syn_ctxt ty | otherwise - = -- Check the context on the data decl - checkValidTheta (DataTyCtxt name) (tyConStupidTheta tc) `thenM_` + = do -- Check the context on the data decl + checkValidTheta (DataTyCtxt name) (tyConStupidTheta tc) -- Check arg types of data constructors - mappM_ (checkValidDataCon tc) data_cons `thenM_` + mapM_ (checkValidDataCon tc) data_cons -- Check that fields with the same name share a type - mappM_ check_fields groups + mapM_ check_fields groups where syn_ctxt = TySynCtxt name @@ -997,7 +1059,10 @@ checkValidDataCon tc con addErrCtxt (dataConCtxt con) $ do { checkTc (dataConTyCon con == tc) (badDataConTyCon con) ; checkValidType ctxt (dataConUserType con) - ; ifM (isNewTyCon tc) (checkNewDataCon con) + ; checkValidMonoType (dataConOrigResTy con) + -- Disallow MkT :: T (forall a. a->a) + -- Reason: it's really the argument of an equality constraint + ; when (isNewTyCon tc) (checkNewDataCon con) } where ctxt = ConArgCtxt (dataConName con) @@ -1010,27 +1075,32 @@ checkNewDataCon con -- One argument ; checkTc (null eq_spec) (newtypePredError con) -- Return type is (T a b c) - ; checkTc (null ex_tvs && null theta) (newtypeExError con) + ; checkTc (null ex_tvs && null eq_theta && null dict_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 + (_univ_tvs, ex_tvs, eq_spec, eq_theta, dict_theta, arg_tys, _res_ty) = dataConFullSig con ------------------------------- checkValidClass :: Class -> TcM () checkValidClass cls - = do { -- CHECK ARITY 1 FOR HASKELL 1.4 - gla_exts <- doptM Opt_GlasgowExts + = do { constrained_class_methods <- doptM Opt_ConstrainedClassMethods + ; 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 -- Check the class operations - ; mappM_ (check_op gla_exts) op_stuff + ; mapM_ (check_op constrained_class_methods) op_stuff -- Check that if the class has generic methods, then the -- class has only one parameter. We can't do generic @@ -1038,16 +1108,17 @@ 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] - check_op gla_exts (sel_id, dm) + check_op constrained_class_methods (sel_id, dm) = addErrCtxt (classOpCtxt sel_id tau) $ do { checkValidTheta SigmaCtxt (tail theta) -- The 'tail' removes the initial (C a) from the -- class itself, leaving just the method type + ; traceTc (text "class op type" <+> ppr op_ty <+> ppr tau) ; checkValidType (FunSigCtxt op_name) tau -- Check that the type mentions at least one of @@ -1070,11 +1141,11 @@ checkValidClass cls op_ty = idType sel_id (_,theta1,tau1) = tcSplitSigmaTy op_ty (_,theta2,tau2) = tcSplitSigmaTy tau1 - (theta,tau) | gla_exts = (theta1 ++ theta2, tau2) - | otherwise = (theta1, mkPhiTy (tail theta1) tau1) + (theta,tau) | constrained_class_methods = (theta1 ++ theta2, tau2) + | otherwise = (theta1, mkPhiTy (tail theta1) tau1) -- Ugh! The function might have a type like -- op :: forall a. C a => forall b. (Eq b, Eq a) => tau2 - -- With -fglasgow-exts, we want to allow this, even though the inner + -- With -XConstrainedClassMethods, we want to allow this, even though the inner -- forall has an (Eq a) constraint. Whereas in general, each constraint -- in the context of a for-all must mention at least one quantified -- type variable. What a mess! @@ -1099,7 +1170,11 @@ 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), @@ -1143,7 +1218,12 @@ 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 -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) @@ -1156,6 +1236,10 @@ 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")] @@ -1167,12 +1251,12 @@ 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 -XTypeFamilies to allow indexed type families")) ] badGadtIdxTyDecl tc_name = vcat [ ptext SLIT("Illegal generalised algebraic data declaration for") <+> @@ -1183,9 +1267,13 @@ tooManyParmsErr tc_name = ptext SLIT("Family instance has too many parameters:") <+> quotes (ppr tc_name) -tooFewParmsErr tc_name - = ptext SLIT("Family instance has too few parameters:") <+> - quotes (ppr tc_name) +tooFewParmsErr arity + = ptext SLIT("Family instance has too few parameters; expected") <+> + ppr arity + +wrongNumberOfParmsErr exp_arity + = ptext SLIT("Number of parameters must match family declaration; expected") + <+> ppr exp_arity badBootFamInstDeclErr = ptext SLIT("Illegal family instance in hs-boot file") @@ -1194,12 +1282,11 @@ 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) 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}