X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Fcompiler%2Ftypecheck%2FTcClassDcl.lhs;h=7f8ffda94a883039906c959f4e544d0aa1d45856;hb=9fdd90b00f159463165f739c44943e53fb553c19;hp=67b17c470efc316cc2dd490040473a245d42a29c;hpb=5f67848a9c686f64bd4960a40a0e109f286df74b;p=ghc-hetmet.git diff --git a/ghc/compiler/typecheck/TcClassDcl.lhs b/ghc/compiler/typecheck/TcClassDcl.lhs index 67b17c4..7f8ffda 100644 --- a/ghc/compiler/typecheck/TcClassDcl.lhs +++ b/ghc/compiler/typecheck/TcClassDcl.lhs @@ -4,47 +4,47 @@ \section[TcClassDcl]{Typechecking class declarations} \begin{code} -module TcClassDcl ( tcClassDecl1, tcClassDecls2, mkImplicitClassBinds, +module TcClassDcl ( tcClassDecl1, tcClassDecls2, tcMethodBind, badMethodErr ) where #include "HsVersions.h" -import HsSyn ( HsDecl(..), TyClDecl(..), Sig(..), MonoBinds(..), +import HsSyn ( TyClDecl(..), Sig(..), MonoBinds(..), HsExpr(..), HsLit(..), HsType(..), HsPred(..), mkSimpleMatch, andMonoBinds, andMonoBindList, - isClassDecl, isClassOpSig, isPragSig, - getClassDeclSysNames, tyClDeclName + isClassOpSig, isPragSig, + getClassDeclSysNames, ) import BasicTypes ( TopLevelFlag(..), RecFlag(..) ) import RnHsSyn ( RenamedTyClDecl, RenamedClassOpSig, RenamedMonoBinds, - RenamedContext, RenamedHsDecl, RenamedSig, + RenamedContext, RenamedSig, maybeGenericMatch ) -import TcHsSyn ( TcMonoBinds, idsToMonoBinds ) +import TcHsSyn ( TcMonoBinds ) -import Inst ( InstOrigin(..), LIE, emptyLIE, plusLIE, plusLIEs, - newDicts, newMethod ) -import TcEnv ( TcId, TcEnv, RecTcEnv, TyThingDetails(..), tcAddImportedIdInfo, +import Inst ( Inst, InstOrigin(..), LIE, emptyLIE, plusLIE, plusLIEs, + instToId, newDicts, newMethod ) +import TcEnv ( RecTcEnv, TyThingDetails(..), tcAddImportedIdInfo, tcLookupClass, tcExtendTyVarEnvForMeths, tcExtendGlobalTyVars, - tcExtendLocalValEnv, tcExtendTyVarEnv, newDefaultMethodName + tcExtendLocalValEnv, tcExtendTyVarEnv ) import TcBinds ( tcBindWithSigs, tcSpecSigs ) -import TcMonoType ( tcHsSigType, tcClassContext, checkSigTyVars, checkAmbiguity, sigCtxt, mkTcSig ) -import TcSimplify ( tcSimplifyAndCheck, bindInstsOfLocalFuns ) -import TcType ( TcType, TcTyVar, tcInstTyVars, zonkTcSigTyVars ) +import TcMonoType ( tcHsRecType, tcRecClassContext, checkSigTyVars, checkAmbiguity, sigCtxt, mkTcSig ) +import TcSimplify ( tcSimplifyCheck, bindInstsOfLocalFuns ) +import TcType ( TcType, TcTyVar, tcInstTyVars ) import TcMonad import Generics ( mkGenericRhs, validGenericMethodType ) import PrelInfo ( nO_METHOD_BINDING_ERROR_ID ) -import Class ( classTyVars, classBigSig, classSelIds, classTyCon, classTvsFds, - Class, ClassOpItem, DefMeth (..), FunDep ) +import Class ( classTyVars, classBigSig, classTyCon, + Class, ClassOpItem, DefMeth (..) ) import MkId ( mkDictSelId, mkDataConId, mkDataConWrapId, mkDefaultMethodId ) import DataCon ( mkDataCon, notMarkedStrict ) import Id ( Id, idType, idName ) import Module ( Module ) -import Name ( Name, NamedThing(..), isFrom ) -import Name ( NameEnv, lookupNameEnv, emptyNameEnv, unitNameEnv, plusNameEnv, nameEnvElts ) +import Name ( Name, NamedThing(..) ) +import NameEnv ( NameEnv, lookupNameEnv, emptyNameEnv, unitNameEnv, plusNameEnv, nameEnvElts ) import NameSet ( emptyNameSet ) import Outputable import Type ( Type, ClassContext, mkTyVarTys, mkDictTys, mkClassPred, @@ -55,7 +55,7 @@ import VarSet ( mkVarSet, emptyVarSet ) import CmdLineOpts import ErrUtils ( dumpIfSet ) import Util ( count ) -import Maybes ( seqMaybe, maybeToBool, orElse ) +import Maybes ( seqMaybe, maybeToBool ) \end{code} @@ -100,36 +100,50 @@ Death to "ExpandingDicts". %************************************************************************ \begin{code} -tcClassDecl1 :: RecTcEnv -> RenamedTyClDecl -> TcM (Name, TyThingDetails) -tcClassDecl1 rec_env - (ClassDecl context class_name - tyvar_names fundeps class_sigs def_methods - sys_names src_loc) + +tcClassDecl1 :: RecFlag -> RecTcEnv -> RenamedTyClDecl -> TcM (Name, TyThingDetails) +tcClassDecl1 is_rec rec_env + (ClassDecl {tcdCtxt = context, tcdName = class_name, + tcdTyVars = tyvar_names, tcdFDs = fundeps, + tcdSigs = class_sigs, tcdMeths = def_methods, + tcdSysNames = sys_names, tcdLoc = src_loc}) = -- CHECK ARITY 1 FOR HASKELL 1.4 - doptsTc Opt_GlasgowExts `thenTc` \ glaExts -> - checkTc (glaExts || length tyvar_names == 1) - (classArityErr class_name) `thenTc_` + doptsTc Opt_GlasgowExts `thenTc` \ gla_ext_opt -> + let + gla_exts = gla_ext_opt || not (maybeToBool def_methods) + -- Accept extensions if gla_exts is on, + -- or if we're looking at an interface file decl + in -- (in which case def_methods = Nothing -- LOOK THINGS UP IN THE ENVIRONMENT tcLookupClass class_name `thenTc` \ clas -> let - (tyvars, fds) = classTvsFds clas + tyvars = classTyVars clas op_sigs = filter isClassOpSig class_sigs op_names = [n | ClassOpSig n _ _ _ <- op_sigs] (_, datacon_name, datacon_wkr_name, sc_sel_names) = getClassDeclSysNames sys_names in tcExtendTyVarEnv tyvars $ - -- CHECK THAT THE DEFAULT BINDINGS ARE LEGAL - checkDefaultBinds clas op_names def_methods `thenTc` \ dm_info -> - checkGenericClassIsUnary clas dm_info `thenTc_` + -- SOURCE-CODE CONSISTENCY CHECKS + (case def_methods of + Nothing -> -- Not source + returnTc Nothing + + Just dms -> -- Source so do error checks + checkTc (gla_exts || length tyvar_names == 1) + (classArityErr class_name) `thenTc_` + + checkDefaultBinds clas op_names dms `thenTc` \ dm_env -> + checkGenericClassIsUnary clas dm_env `thenTc_` + returnTc (Just dm_env) + ) `thenTc` \ mb_dm_env -> -- CHECK THE CONTEXT - tcSuperClasses clas context sc_sel_names `thenTc` \ (sc_theta, sc_sel_ids) -> + tcSuperClasses is_rec gla_exts clas context sc_sel_names `thenTc` \ (sc_theta, sc_sel_ids) -> -- CHECK THE CLASS SIGNATURES, - mapTc (tcClassSig rec_env clas tyvars fds dm_info) - op_sigs `thenTc` \ sig_stuff -> + mapTc (tcClassSig is_rec rec_env clas tyvars mb_dm_env) op_sigs `thenTc` \ sig_stuff -> -- MAKE THE CLASS DETAILS let @@ -154,12 +168,20 @@ tcClassDecl1 rec_env \end{code} \begin{code} -checkDefaultBinds :: Class -> [Name] -> RenamedMonoBinds -> TcM (NameEnv (DefMeth Name)) +checkDefaultBinds :: Class -> [Name] -> RenamedMonoBinds + -> TcM (NameEnv Bool) + -- The returned environment says + -- x not in env => no default method + -- x -> True => generic default method + -- x -> False => polymorphic default method + -- Check default bindings -- a) must be for a class op for this class -- b) must be all generic or all non-generic -- and return a mapping from class-op to DefMeth info + -- But do all this only for source binds + checkDefaultBinds clas ops EmptyMonoBinds = returnTc emptyNameEnv checkDefaultBinds clas ops (AndMonoBinds b1 b2) @@ -176,52 +198,44 @@ checkDefaultBinds clas ops (FunMonoBind op _ matches loc) -- Check that all the defns ar generic, or none are checkTc (all_generic || none_generic) (mixedGenericErr op) `thenTc_` - -- Make up the right dm_info - if all_generic then - returnTc (unitNameEnv op GenDefMeth) - else - -- An explicit non-generic default method - newDefaultMethodName op loc `thenNF_Tc` \ dm_name -> - returnTc (unitNameEnv op (DefMeth dm_name)) - + returnTc (unitNameEnv op all_generic) where n_generic = count (maybeToBool . maybeGenericMatch) matches none_generic = n_generic == 0 all_generic = n_generic == length matches -checkGenericClassIsUnary clas dm_info +checkGenericClassIsUnary clas dm_env = -- Check that if the class has generic methods, then the -- class has only one parameter. We can't do generic -- multi-parameter type classes! checkTc (unary || no_generics) (genericMultiParamErr clas) where unary = length (classTyVars clas) == 1 - no_generics = null [() | GenDefMeth <- nameEnvElts dm_info] + no_generics = not (or (nameEnvElts dm_env)) \end{code} \begin{code} -tcSuperClasses :: Class +tcSuperClasses :: RecFlag -> Bool -> Class -> RenamedContext -- class context -> [Name] -- Names for superclass selectors -> TcM (ClassContext, -- the superclass context [Id]) -- superclass selector Ids -tcSuperClasses clas context sc_sel_names +tcSuperClasses is_rec gla_exts clas context sc_sel_names = -- Check the context. -- The renamer has already checked that the context mentions -- only the type variable of the class decl. -- For std Haskell check that the context constrains only tyvars - doptsTc Opt_GlasgowExts `thenTc` \ glaExts -> - (if glaExts then + (if gla_exts then returnTc () else mapTc_ check_constraint context ) `thenTc_` -- Context is already kind-checked - tcClassContext context `thenTc` \ sc_theta -> + tcRecClassContext is_rec context `thenTc` \ sc_theta -> let sc_sel_ids = [mkDictSelId sc_name clas | sc_name <- sc_sel_names] in @@ -236,11 +250,10 @@ tcSuperClasses clas context sc_sel_names is_tyvar other = False -tcClassSig :: RecTcEnv +tcClassSig :: RecFlag -> RecTcEnv -- Knot tying only! -> Class -- ...ditto... -> [TyVar] -- The class type variable, used for error check only - -> [FunDep TyVar] - -> NameEnv (DefMeth Name) -- Info about default methods + -> Maybe (NameEnv Bool) -- Info about default methods -> RenamedClassOpSig -> TcM (Type, -- Type of the method ClassOpItem) -- Selector Id, default-method Id, True if explicit default binding @@ -250,70 +263,56 @@ tcClassSig :: RecTcEnv -- so we distinguish them in checkDefaultBinds, and pass this knowledge in the -- Class.DefMeth data structure. -tcClassSig unf_env clas clas_tyvars fds dm_info - (ClassOpSig op_name maybe_dm op_ty src_loc) +tcClassSig is_rec unf_env clas clas_tyvars maybe_dm_env + (ClassOpSig op_name sig_dm op_ty src_loc) = tcAddSrcLoc src_loc $ -- Check the type signature. NB that the envt *already has* -- bindings for the type variables; see comments in TcTyAndClassDcls. - tcHsSigType op_ty `thenTc` \ local_ty -> + tcHsRecType is_rec op_ty `thenTc` \ local_ty -> + + -- Check for ambiguous class op types let theta = [mkClassPred clas (mkTyVarTys clas_tyvars)] in - -- Check for ambiguous class op types - checkAmbiguity True clas_tyvars theta local_ty `thenTc` \ global_ty -> + checkAmbiguity is_rec True clas_tyvars theta local_ty `thenTc` \ global_ty -> + -- The default method's type should really come from the + -- iface file, since it could be usage-generalised, but this + -- requires altering the mess of knots in TcModule and I'm + -- too scared to do that. Instead, I have disabled generalisation + -- of types of default methods (and dict funs) by annotating them + -- TyGenNever (in MkId). Ugh! KSW 1999-09. let -- Build the selector id and default method id - sel_id = mkDictSelId op_name clas - - dm_info_name = maybe_dm `orElse` lookupNameEnv dm_info op_name `orElse` NoDefMeth - - dm_info_id = case dm_info_name of - NoDefMeth -> NoDefMeth - GenDefMeth -> GenDefMeth - DefMeth dm_name -> DefMeth (tcAddImportedIdInfo unf_env dm_id) - where - dm_id = mkDefaultMethodId dm_name clas global_ty + sel_id = mkDictSelId op_name clas + dm_id = mkDefaultMethodId dm_name global_ty + DefMeth dm_name = sig_dm + + dm_info = case maybe_dm_env of + Nothing -> iface_dm_info + Just dm_env -> mk_src_dm_info dm_env + + iface_dm_info = case sig_dm of + NoDefMeth -> NoDefMeth + GenDefMeth -> GenDefMeth + DefMeth dm_name -> DefMeth (tcAddImportedIdInfo unf_env dm_id) + + mk_src_dm_info dm_env = case lookupNameEnv dm_env op_name of + Nothing -> NoDefMeth + Just True -> GenDefMeth + Just False -> DefMeth dm_id in -- Check that for a generic method, the type of -- the method is sufficiently simple - checkTc (dm_info_name /= GenDefMeth || validGenericMethodType local_ty) + checkTc (dm_info /= GenDefMeth || validGenericMethodType local_ty) (badGenericMethodType op_name op_ty) `thenTc_` - returnTc (local_ty, (sel_id, dm_info_id)) -\end{code} - - -%************************************************************************ -%* * -\subsection[ClassDcl-pass2]{Class decls pass 2: default methods} -%* * -%************************************************************************ - -@mkImplicitClassBinds@ produces a binding for the selector function for each method -and superclass dictionary. - -\begin{code} -mkImplicitClassBinds :: Module -> [Class] -> NF_TcM ([Id], TcMonoBinds) -mkImplicitClassBinds this_mod classes - = returnNF_Tc (concat cls_ids_s, andMonoBindList binds_s) - -- The selector binds are already in the selector Id's unfoldings - -- We don't return the data constructor etc from the class, - -- because that's done via the class's TyCon - where - (cls_ids_s, binds_s) = unzip (map mk_implicit classes) - - mk_implicit clas = (sel_ids, binds) - where - sel_ids = classSelIds clas - binds | isFrom this_mod clas = idsToMonoBinds sel_ids - | otherwise = EmptyMonoBinds + returnTc (local_ty, (sel_id, dm_info)) \end{code} - %************************************************************************ %* * \subsection[Default methods]{Default methods} @@ -379,14 +378,13 @@ The function @tcClassDecls2@ just arranges to apply @tcClassDecl2@ to each local class decl. \begin{code} -tcClassDecls2 :: Module -> [RenamedHsDecl] -> NF_TcM (LIE, TcMonoBinds) +tcClassDecls2 :: Module -> [RenamedTyClDecl] -> NF_TcM (LIE, TcMonoBinds) tcClassDecls2 this_mod decls = foldr combine (returnNF_Tc (emptyLIE, EmptyMonoBinds)) - [tcClassDecl2 cls_decl | TyClD cls_decl <- decls, - isClassDecl cls_decl, - isFrom this_mod (tyClDeclName cls_decl)] + [tcClassDecl2 cls_decl | cls_decl@(ClassDecl {tcdMeths = Just _}) <- decls] + -- The 'Just' picks out source ClassDecls where combine tc1 tc2 = tc1 `thenNF_Tc` \ (lie1, binds1) -> tc2 `thenNF_Tc` \ (lie2, binds2) -> @@ -401,9 +399,9 @@ tcClassDecls2 this_mod decls tcClassDecl2 :: RenamedTyClDecl -- The class declaration -> NF_TcM (LIE, TcMonoBinds) -tcClassDecl2 (ClassDecl context class_name - tyvar_names _ sigs default_binds _ src_loc) - = -- A locally defined class +tcClassDecl2 (ClassDecl {tcdName = class_name, tcdSigs = sigs, + tcdMeths = Just default_binds, tcdLoc = src_loc}) + = -- The 'Just' picks out source ClassDecls recoverNF_Tc (returnNF_Tc (emptyLIE, EmptyMonoBinds)) $ tcAddSrcLoc src_loc $ tcLookupClass class_name `thenNF_Tc` \ clas -> @@ -440,32 +438,30 @@ tcDefMeth clas tyvars binds_in prags op_item@(_, DefMeth dm_id) let theta = [(mkClassPred clas inst_tys)] in - newDicts origin theta `thenNF_Tc` \ (this_dict, [this_dict_id]) -> + newDicts origin theta `thenNF_Tc` \ [this_dict] -> tcExtendTyVarEnvForMeths tyvars clas_tyvars ( tcMethodBind clas origin clas_tyvars inst_tys theta binds_in prags False op_item - ) `thenTc` \ (defm_bind, insts_needed, (_, local_dm_id)) -> + ) `thenTc` \ (defm_bind, insts_needed, local_dm_inst) -> tcAddErrCtxt (defltMethCtxt clas) $ - -- tcMethodBind has checked that the class_tyvars havn't - -- been unified with each other or another type, but we must - -- still zonk them before passing them to tcSimplifyAndCheck - zonkTcSigTyVars clas_tyvars `thenNF_Tc` \ clas_tyvars' -> - -- Check the context - tcSimplifyAndCheck + tcSimplifyCheck (ptext SLIT("class") <+> ppr clas) - (mkVarSet clas_tyvars') - this_dict - insts_needed `thenTc` \ (const_lie, dict_binds) -> + clas_tyvars + [this_dict] + insts_needed `thenTc` \ (const_lie, dict_binds) -> + + -- Simplification can do unification + checkSigTyVars clas_tyvars emptyVarSet `thenTc` \ clas_tyvars' -> let full_bind = AbsBinds clas_tyvars' - [this_dict_id] - [(clas_tyvars', dm_id, local_dm_id)] + [instToId this_dict] + [(clas_tyvars', dm_id, instToId local_dm_inst)] emptyNameSet -- No inlines (yet) (dict_binds `andMonoBinds` defm_bind) in @@ -503,18 +499,20 @@ tcMethodBind -> [RenamedSig] -- Pramgas (just for this one) -> Bool -- True <=> This method is from an instance declaration -> ClassOpItem -- The method selector and default-method Id - -> TcM (TcMonoBinds, LIE, (LIE, TcId)) + -> TcM (TcMonoBinds, LIE, Inst) tcMethodBind clas origin inst_tyvars inst_tys inst_theta meth_binds prags is_inst_decl (sel_id, dm_info) = tcGetSrcLoc `thenNF_Tc` \ loc -> - newMethod origin sel_id inst_tys `thenNF_Tc` \ meth@(_, meth_id) -> - mkTcSig meth_id loc `thenNF_Tc` \ sig_info -> + newMethod origin sel_id inst_tys `thenNF_Tc` \ meth -> let + meth_id = instToId meth meth_name = idName meth_id sig_msg = ptext SLIT("When checking the expected type for class method") <+> ppr sel_id meth_prags = find_prags (idName sel_id) meth_name prags in + mkTcSig meth_id loc `thenNF_Tc` \ sig_info -> + -- Figure out what method binding to use -- If the user suppplied one, use it, else construct a default one (case find_bind (idName sel_id) meth_name meth_binds of