X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=compiler%2Ftypecheck%2FTcTyClsDecls.lhs;h=f827117623191e5a9d23f15d4b91dc91f0e1b15e;hb=f6a68d3109f977fe4431df51d1412d916e7c08da;hp=ee847f5ec8257f1e0623961b06aacda5f72eb861;hpb=b1086a0798f69f437d9546062878619a3681313a;p=ghc-hetmet.git diff --git a/compiler/typecheck/TcTyClsDecls.lhs b/compiler/typecheck/TcTyClsDecls.lhs index ee847f5..f827117 100644 --- a/compiler/typecheck/TcTyClsDecls.lhs +++ b/compiler/typecheck/TcTyClsDecls.lhs @@ -17,6 +17,7 @@ import HsTypes import BasicTypes import HscTypes import BuildTyCl +import TcUnify import TcRnMonad import TcEnv import TcTyDecls @@ -44,7 +45,7 @@ import ListSetOps import Digraph import DynFlags -import Data.List ( partition, elemIndex ) +import Data.List import Control.Monad ( mplus ) \end{code} @@ -241,9 +242,9 @@ tcFamInstDecl (L loc decl) tcAddDeclCtxt decl $ do { -- type families require -ftype-families and can't be in an -- hs-boot file - ; gla_exts <- doptM Opt_TypeFamilies + ; 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 @@ -259,15 +260,32 @@ 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 at least as many type parameters as the family declaration + -- specified + ; let famArity = tyConArity family + ; checkTc (length k_typats >= famArity) $ tooFewParmsErr famArity + -- (2) type check type equation ; tcTyVarBndrs k_tvs $ \t_tvs -> do { -- turn kinded into proper tyvars ; t_typats <- mappM tcHsKindedType k_typats ; t_rhs <- tcHsKindedType k_rhs - -- (3) construct representation tycon + -- all parameters in excess of the family arity must be variables + ; checkTc (all isTyVarTy $ drop famArity t_typats) $ excessParmVarErr + + -- (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)) @@ -289,23 +307,29 @@ 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 <- 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 - - -- (3) construct representation tycon + -- (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)) @@ -314,7 +338,7 @@ 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? @@ -332,6 +356,27 @@ 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 -- - @@ -339,7 +384,7 @@ 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) @@ -499,18 +544,15 @@ 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' <- mappM (wrapLocM (kcFamilyDecl tvs')) ats + ; sigs' <- mappM (wrapLocM kc_sig) sigs ; return (decl {tcdTyVars = tvs', tcdCtxt = ctxt', tcdSigs = sigs', tcdATs = ats'}) } where @@ -562,13 +604,18 @@ 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' <- mappM 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' <- 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 @@ -576,6 +623,25 @@ 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} @@ -656,21 +722,23 @@ 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 @@ -775,8 +843,8 @@ 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 @@ -1018,18 +1086,20 @@ checkNewDataCon 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 + ; mappM_ (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 @@ -1037,11 +1107,11 @@ 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 @@ -1069,11 +1139,11 @@ 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! @@ -1098,7 +1168,11 @@ 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), @@ -1142,7 +1216,7 @@ 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 -XGADTs to allow GADTs")) ] badStupidTheta tc_name = ptext SLIT("A data type declared in GADT style cannot have a context:") <+> quotes (ppr tc_name) @@ -1170,12 +1244,12 @@ 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 -ftype-families 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") <+> @@ -1186,9 +1260,12 @@ 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 + +excessParmVarErr + = ptext SLIT("Additional instance parameters must be variables") badBootFamInstDeclErr = ptext SLIT("Illegal family instance in hs-boot file") @@ -1201,7 +1278,16 @@ 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("(-fglasgow-exts permits this)")] + nest 2 $ ptext SLIT("(-XEmptyDataDecls permits this)")] \end{code}