X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Fcompiler%2Ftypecheck%2FTcInstDcls.lhs;h=aef778a22341ab5b50fa254a7ccec2e3356e8d4a;hb=0b4ef1955eb1480700e19720f38a59e3518408d7;hp=9b53a04dd29e438062f7b2edebd2f0f23a5d6f59;hpb=d68887047bcfb9021151f768fe1a22df2d3fbe1e;p=ghc-hetmet.git diff --git a/ghc/compiler/typecheck/TcInstDcls.lhs b/ghc/compiler/typecheck/TcInstDcls.lhs index 9b53a04..aef778a 100644 --- a/ghc/compiler/typecheck/TcInstDcls.lhs +++ b/ghc/compiler/typecheck/TcInstDcls.lhs @@ -9,10 +9,10 @@ module TcInstDcls ( tcInstDecls1, tcInstDecls2, tcAddDeclCtxt ) where #include "HsVersions.h" -import CmdLineOpts ( DynFlag(..), dopt ) +import CmdLineOpts ( DynFlag(..) ) import HsSyn ( HsDecl(..), InstDecl(..), TyClDecl(..), HsType(..), - MonoBinds(..), HsExpr(..), HsLit(..), Sig(..), + MonoBinds(..), HsExpr(..), HsLit(..), Sig(..), HsTyVarBndr(..), andMonoBindList, collectMonoBinders, isClassDecl, toHsType ) import RnHsSyn ( RenamedHsBinds, RenamedInstDecl, RenamedHsDecl, @@ -23,7 +23,11 @@ import TcHsSyn ( TcMonoBinds, mkHsConApp ) import TcBinds ( tcSpecSigs ) import TcClassDcl ( tcMethodBind, badMethodErr ) import TcMonad -import TcType ( tcInstType ) +import TcMType ( tcInstTyVars, checkValidTheta, checkValidInstHead, instTypeErr, + UserTypeCtxt(..), SourceTyCtxt(..) ) +import TcType ( tcSplitDFunTy, mkClassPred, mkTyVarTy, + tcSplitSigmaTy, tcSplitPredTy_maybe, getClassPredTys + ) import Inst ( InstOrigin(..), newDicts, instToId, LIE, mkLIE, emptyLIE, plusLIE, plusLIEs ) @@ -32,43 +36,35 @@ import TcEnv ( TcEnv, tcExtendGlobalValEnv, tcExtendTyVarEnvForMeths, tcAddImportedIdInfo, tcLookupClass, InstInfo(..), pprInstInfo, simpleInstInfoTyCon, - simpleInstInfoTy, newDFunName, tcExtendTyVarEnv, + simpleInstInfoTy, newDFunName, isLocalThing, ) import InstEnv ( InstEnv, extendInstEnv ) -import TcMonoType ( tcTyVars, tcHsSigType, kcHsSigType, checkSigTyVars ) +import PprType ( pprClassPred ) +import TcMonoType ( tcHsTyVars, kcHsSigType, tcHsType, tcHsSigType, checkSigTyVars ) import TcSimplify ( tcSimplifyCheck ) import HscTypes ( HomeSymbolTable, DFunId, ModDetails(..), PackageInstEnv, PersistentRenamerState ) +import Subst ( substTy, substTheta ) import DataCon ( classDataCon ) import Class ( Class, DefMeth(..), classBigSig ) import Var ( idName, idType ) import VarSet ( emptyVarSet ) -import Maybes ( maybeToBool ) +import Id ( setIdLocalExported ) import MkId ( mkDictFunId ) import FunDeps ( checkInstFDs ) import Generics ( validGenericInstanceType ) import Module ( Module, foldModuleEnv ) import Name ( getSrcLoc ) -import NameSet ( emptyNameSet, unitNameSet, nameSetToList ) +import NameSet ( unitNameSet, emptyNameSet, nameSetToList ) import PrelInfo ( eRROR_ID ) -import PprType ( pprClassPred, pprPred ) -import TyCon ( TyCon, isSynTyCon ) -import Type ( splitDFunTy, isTyVarTy, - splitTyConApp_maybe, splitDictTy, - splitForAllTys, - tyVarsOfTypes, mkClassPred, mkTyVarTy, - isTyVarClassPred, inheritablePred - ) +import TyCon ( TyCon ) import Subst ( mkTopTyVarSubst, substTheta ) -import VarSet ( varSetElems ) -import TysWiredIn ( genericTyCons, isFFIArgumentTy, isFFIImportResultTy ) -import PrelNames ( cCallableClassKey, cReturnableClassKey, hasKey ) +import TysWiredIn ( genericTyCons ) import Name ( Name ) import SrcLoc ( SrcLoc ) -import VarSet ( varSetElems ) import Unique ( Uniquable(..) ) import BasicTypes ( NewOrData(..), Fixity ) import ErrUtils ( dumpIfSet_dyn ) @@ -198,7 +194,10 @@ tcInstDecls1 inst_env0 prs hst unf_env get_fixity this_mod decls imported_dfuns = map (tcAddImportedIdInfo unf_env . iDFunId) imported_inst_info hst_dfuns = foldModuleEnv ((++) . md_insts) [] hst - in + in + +-- pprTrace "tcInstDecls" (vcat [ppr imported_dfuns, ppr hst_dfuns]) $ + addInstDFuns inst_env0 imported_dfuns `thenNF_Tc` \ inst_env1 -> addInstDFuns inst_env1 hst_dfuns `thenNF_Tc` \ inst_env2 -> addInstInfos inst_env2 local_inst_info `thenNF_Tc` \ inst_env3 -> @@ -222,56 +221,59 @@ addInstInfos :: InstEnv -> [InstInfo] -> NF_TcM InstEnv addInstInfos inst_env infos = addInstDFuns inst_env (map iDFunId infos) addInstDFuns :: InstEnv -> [DFunId] -> NF_TcM InstEnv -addInstDFuns dfuns infos +addInstDFuns inst_env dfuns = getDOptsTc `thenTc` \ dflags -> let - (inst_env', errs) = extendInstEnv dflags dfuns infos + (inst_env', errs) = extendInstEnv dflags inst_env dfuns in addErrsTc errs `thenNF_Tc_` + traceTc (text "Adding instances:" <+> vcat (map pp dfuns)) `thenTc_` returnTc inst_env' + where + pp dfun = ppr dfun <+> dcolon <+> ppr (idType dfun) \end{code} \begin{code} tcInstDecl1 :: RenamedInstDecl -> NF_TcM [InstInfo] -- Deal with a single instance declaration +-- Type-check all the stuff before the "where" tcInstDecl1 decl@(InstDecl poly_ty binds uprags maybe_dfun_name src_loc) = -- Prime error recovery, set source location recoverNF_Tc (returnNF_Tc []) $ tcAddSrcLoc src_loc $ + tcAddErrCtxt (instDeclCtxt poly_ty) $ - -- Type-check all the stuff before the "where" - tcAddErrCtxt (instDeclCtxt poly_ty) ( - tcHsSigType poly_ty - ) `thenTc` \ poly_ty' -> + -- Typecheck the instance type itself. We can't use + -- tcHsSigType, because it's not a valid user type. + kcHsSigType poly_ty `thenTc_` + tcHsType poly_ty `thenTc` \ poly_ty' -> let - (tyvars, theta, clas, inst_tys) = splitDFunTy poly_ty' + (tyvars, theta, tau) = tcSplitSigmaTy poly_ty' + (clas,inst_tys) = case tcSplitPredTy_maybe tau of { Just st -> getClassPredTys st } + -- The checkValidInstHead makes sure these splits succeed in - (case maybe_dfun_name of Nothing -> -- A source-file instance declaration - -- Check for respectable instance type, and context -- but only do this for non-imported instance decls. -- Imported ones should have been checked already, and may indeed -- contain something illegal in normal Haskell, notably -- instance CCallable [Char] - getDOptsTc `thenTc` \ dflags -> - checkInstValidity dflags theta clas inst_tys `thenTc_` - - -- Make the dfun id and return it - newDFunName clas inst_tys src_loc `thenNF_Tc` \ dfun_name -> - returnNF_Tc (True, dfun_name) + checkValidTheta InstThetaCtxt theta `thenTc_` + checkValidInstHead tau `thenTc_` + checkTc (checkInstFDs theta clas inst_tys) + (instTypeErr (pprClassPred clas inst_tys) msg) `thenTc_` + newDFunName clas inst_tys src_loc Just dfun_name -> -- An interface-file instance declaration - -- Make the dfun id - returnNF_Tc (False, dfun_name) - ) `thenNF_Tc` \ (is_local, dfun_name) -> - + returnNF_Tc dfun_name + ) `thenNF_Tc` \ dfun_name -> let dfun_id = mkDictFunId dfun_name clas tyvars inst_tys theta in - returnTc [InstInfo { iDFunId = dfun_id, - iBinds = binds, iPrags = uprags }] + returnTc [InstInfo { iDFunId = dfun_id, iBinds = binds, iPrags = uprags }] + where + msg = parens (ptext SLIT("the instance types do not agree with the functional dependencies of the class")) \end{code} @@ -328,7 +330,7 @@ get_generics decl@(ClassDecl {tcdName = class_name, tcdMeths = Just def_methods, | null groups = returnTc [] -- The comon case: no generic default methods - | otherwise -- A local class decl with generic default methods + | otherwise -- A source class decl with generic default methods = recoverNF_Tc (returnNF_Tc []) $ tcAddDeclCtxt decl $ tcLookupClass class_name `thenTc` \ clas -> @@ -395,12 +397,13 @@ mkGenericInstance clas loc (hs_ty, binds) -- For example: instance (C a, C b) => C (a+b) where { binds } = -- Extract the universally quantified type variables - tcTyVars (nameSetToList (extractHsTyVars hs_ty)) - (kcHsSigType hs_ty) `thenTc` \ tyvars -> - tcExtendTyVarEnv tyvars $ + let + sig_tvs = map UserTyVar (nameSetToList (extractHsTyVars hs_ty)) + in + tcHsTyVars sig_tvs (kcHsSigType hs_ty) $ \ tyvars -> -- Type-check the instance type, and check its form - tcHsSigType hs_ty `thenTc` \ inst_ty -> + tcHsSigType GenPatCtxt hs_ty `thenTc` \ inst_ty -> checkTc (validGenericInstanceType inst_ty) (badGenericInstanceType binds) `thenTc_` @@ -517,10 +520,14 @@ tcInstDecl2 (InstInfo { iDFunId = dfun_id, tcAddErrCtxt (instDeclCtxt (toHsType (idType dfun_id))) $ -- Instantiate the instance decl with tc-style type variables - tcInstType (idType dfun_id) `thenNF_Tc` \ (inst_tyvars', dfun_theta', dict_ty') -> let - (clas, inst_tys') = splitDictTy dict_ty' - origin = InstanceDeclOrigin + (inst_tyvars, dfun_theta, clas, inst_tys) = tcSplitDFunTy (idType dfun_id) + in + tcInstTyVars inst_tyvars `thenNF_Tc` \ (inst_tyvars', _, tenv) -> + let + inst_tys' = map (substTy tenv) inst_tys + dfun_theta' = substTheta tenv dfun_theta + origin = InstanceDeclOrigin (class_tyvars, sc_theta, _, op_items) = classBigSig clas @@ -532,11 +539,6 @@ tcInstDecl2 (InstInfo { iDFunId = dfun_id, -- Find any definitions in monobinds that aren't from the class bad_bndrs = collectMonoBinders monobinds `minusList` sel_names - - -- The type variable from the dict fun actually scope - -- over the bindings. They were gotten from - -- the original instance declaration - (inst_tyvars, _) = splitForAllTys (idType dfun_id) in -- Check that all the method bindings come from this class mapTc (addErrTc . badMethodErr clas) bad_bndrs `thenNF_Tc_` @@ -547,6 +549,9 @@ tcInstDecl2 (InstInfo { iDFunId = dfun_id, newDicts origin [mkClassPred clas inst_tys'] `thenNF_Tc` \ [this_dict] -> tcExtendTyVarEnvForMeths inst_tyvars inst_tyvars' ( + -- The type variable from the dict fun actually scope + -- over the bindings. They were gotten from + -- the original instance declaration tcExtendGlobalValEnv dm_ids ( -- Default-method Ids may be mentioned in synthesised RHSs @@ -599,14 +604,22 @@ tcInstDecl2 (InstInfo { iDFunId = dfun_id, -- Create the result bindings let + local_dfun_id = setIdLocalExported dfun_id + -- Reason for setIdLocalExported: see notes with MkId.mkDictFunId + dict_constr = classDataCon clas scs_and_meths = map instToId (sc_dicts ++ meth_insts) this_dict_id = instToId this_dict - inlines = unitNameSet (idName dfun_id) + inlines | null dfun_arg_dicts = emptyNameSet + | otherwise = unitNameSet (idName dfun_id) -- Always inline the dfun; this is an experimental decision -- because it makes a big performance difference sometimes. -- Often it means we can do the method selection, and then -- inline the method as well. Marcin's idea; see comments below. + -- + -- BUT: don't inline it if it's a constant dictionary; + -- we'll get all the benefit without inlining, and we get + -- a **lot** of code duplication if we inline it dict_rhs | null scs_and_meths @@ -638,7 +651,7 @@ tcInstDecl2 (InstInfo { iDFunId = dfun_id, = AbsBinds zonked_inst_tyvars (map instToId dfun_arg_dicts) - [(inst_tyvars', dfun_id, this_dict_id)] + [(inst_tyvars', local_dfun_id, this_dict_id)] inlines (lie_binds1 `AndMonoBinds` lie_binds2 `AndMonoBinds` @@ -742,102 +755,6 @@ simplified: only zeze2 is extracted and its body is simplified. %************************************************************************ %* * -\subsection{Checking for a decent instance type} -%* * -%************************************************************************ - -@scrutiniseInstanceHead@ checks the type {\em and} its syntactic constraints: -it must normally look like: @instance Foo (Tycon a b c ...) ...@ - -The exceptions to this syntactic checking: (1)~if the @GlasgowExts@ -flag is on, or (2)~the instance is imported (they must have been -compiled elsewhere). In these cases, we let them go through anyway. - -We can also have instances for functions: @instance Foo (a -> b) ...@. - -\begin{code} -checkInstValidity dflags theta clas inst_tys - | null errs = returnTc () - | otherwise = addErrsTc errs `thenNF_Tc_` failTc - where - errs = checkInstHead dflags theta clas inst_tys ++ - [err | pred <- theta, err <- checkInstConstraint dflags pred] - -checkInstConstraint dflags pred - -- Checks whether a predicate is legal in the - -- context of an instance declaration - | ok = [] - | otherwise = [instConstraintErr pred] - where - ok = inheritablePred pred && - (isTyVarClassPred pred || arbitrary_preds_ok) - - arbitrary_preds_ok = dopt Opt_AllowUndecidableInstances dflags - - -checkInstHead dflags theta clas inst_taus - | -- CCALL CHECK - -- A user declaration of a CCallable/CReturnable instance - -- must be for a "boxed primitive" type. - (clas `hasKey` cCallableClassKey - && not (ccallable_type dflags first_inst_tau)) - || - (clas `hasKey` cReturnableClassKey - && not (creturnable_type first_inst_tau)) - = [nonBoxedPrimCCallErr clas first_inst_tau] - - -- If GlasgowExts then check at least one isn't a type variable - | dopt Opt_GlasgowExts dflags - = -- GlasgowExts case - check_tyvars dflags clas inst_taus ++ check_fundeps dflags theta clas inst_taus - - -- WITH HASKELL 1.4, MUST HAVE C (T a b c) - | not (length inst_taus == 1 && - maybeToBool maybe_tycon_app && -- Yes, there's a type constuctor - not (isSynTyCon tycon) && -- ...but not a synonym - all isTyVarTy arg_tys && -- Applied to type variables - length (varSetElems (tyVarsOfTypes arg_tys)) == length arg_tys - -- This last condition checks that all the type variables are distinct - ) - = [instTypeErr clas inst_taus - (text "the instance type must be of form (T a b c)" $$ - text "where T is not a synonym, and a,b,c are distinct type variables")] - - | otherwise - = [] - - where - (first_inst_tau : _) = inst_taus - - -- Stuff for algebraic or -> type - maybe_tycon_app = splitTyConApp_maybe first_inst_tau - Just (tycon, arg_tys) = maybe_tycon_app - - ccallable_type dflags ty = isFFIArgumentTy dflags False {- Not safe call -} ty - creturnable_type ty = isFFIImportResultTy dflags ty - -check_tyvars dflags clas inst_taus - -- Check that at least one isn't a type variable - -- unless -fallow-undecideable-instances - | dopt Opt_AllowUndecidableInstances dflags = [] - | not (all isTyVarTy inst_taus) = [] - | otherwise = [the_err] - where - the_err = instTypeErr clas inst_taus msg - msg = ptext SLIT("There must be at least one non-type-variable in the instance head") - $$ ptext SLIT("Use -fallow-undecidable-instances to lift this restriction") - -check_fundeps dflags theta clas inst_taus - | checkInstFDs theta clas inst_taus = [] - | otherwise = [the_err] - where - the_err = instTypeErr clas inst_taus msg - msg = ptext SLIT("the instance types do not agree with the functional dependencies of the class") -\end{code} - - -%************************************************************************ -%* * \subsection{Error messages} %* * %************************************************************************ @@ -866,12 +783,6 @@ instDeclCtxt inst_ty = ptext SLIT("In the instance declaration for") <+> quotes \end{code} \begin{code} -instConstraintErr pred - = hang (ptext SLIT("Illegal constraint") <+> - quotes (pprPred pred) <+> - ptext SLIT("in instance context")) - 4 (ptext SLIT("(Instance contexts must constrain only type variables)")) - badGenericInstanceType binds = vcat [ptext SLIT("Illegal type pattern in the generic bindings"), nest 4 (ppr binds)] @@ -879,8 +790,6 @@ badGenericInstanceType binds missingGenericInstances missing = ptext SLIT("Missing type patterns for") <+> pprQuotedList missing - - dupGenericInsts tc_inst_infos = vcat [ptext SLIT("More than one type pattern for a single generic type constructor:"), nest 4 (vcat (map ppr_inst_ty tc_inst_infos)), @@ -889,16 +798,6 @@ dupGenericInsts tc_inst_infos where ppr_inst_ty (tc,inst) = ppr (simpleInstInfoTy inst) -instTypeErr clas tys msg - = sep [ptext SLIT("Illegal instance declaration for") <+> - quotes (pprClassPred clas tys), - nest 4 (parens msg) - ] - -nonBoxedPrimCCallErr clas inst_ty - = hang (ptext SLIT("Unacceptable instance type for ccall-ish class")) - 4 (pprClassPred clas [inst_ty]) - methodCtxt = ptext SLIT("When checking the methods of an instance declaration") superClassCtxt = ptext SLIT("When checking the super-classes of an instance declaration") \end{code}