X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Fcompiler%2Ftypecheck%2FTcInstDcls.lhs;h=6f78e392d0d5e4a9854d57900439cd7b0bf61c5b;hb=efa881239effd5ea4cb403c2c03ebb09fbdfd363;hp=a629162db6ed4ce4cde9e0a44841b9a7e855c61c;hpb=d0f325ce37d6ee322168e44392f10e0ed52f8294;p=ghc-hetmet.git diff --git a/ghc/compiler/typecheck/TcInstDcls.lhs b/ghc/compiler/typecheck/TcInstDcls.lhs index a629162..6f78e39 100644 --- a/ghc/compiler/typecheck/TcInstDcls.lhs +++ b/ghc/compiler/typecheck/TcInstDcls.lhs @@ -1,72 +1,80 @@ % -% (c) The GRASP/AQUA Project, Glasgow University, 1992-1996 +% (c) The GRASP/AQUA Project, Glasgow University, 1992-1998 % \section[TcInstDecls]{Typechecking instance declarations} \begin{code} -module TcInstDcls ( - tcInstDecls1, - tcInstDecls2 - ) where +module TcInstDcls ( tcInstDecls1, tcInstDecls2, tcAddDeclCtxt ) where #include "HsVersions.h" -import HsSyn ( HsDecl(..), InstDecl(..), - HsBinds(..), MonoBinds(..), GRHSsAndBinds(..), GRHS(..), - HsExpr(..), InPat(..), HsLit(..), Sig(..), - unguardedRHS, - collectMonoBinders, andMonoBinds - ) -import HsBinds ( sigsForMe ) -import RnHsSyn ( RenamedHsBinds, RenamedMonoBinds, - RenamedInstDecl, RenamedHsExpr, - RenamedSig, RenamedHsDecl + +import CmdLineOpts ( DynFlag(..), dopt ) + +import HsSyn ( HsDecl(..), InstDecl(..), TyClDecl(..), + MonoBinds(..), HsExpr(..), HsLit(..), Sig(..), + andMonoBindList, collectMonoBinders, isClassDecl ) -import TcHsSyn ( TcMonoBinds, TcIdOcc(..), TcIdBndr, - maybeBoxedPrimType, tcIdType +import RnHsSyn ( RenamedHsBinds, RenamedInstDecl, RenamedHsDecl, RenamedMonoBinds, + RenamedTyClDecl, RenamedHsType, + extractHsTyVars, maybeGenericMatch ) - -import TcBinds ( tcPragmaSigs ) +import TcHsSyn ( TcMonoBinds, mkHsConApp ) +import TcBinds ( tcSpecSigs ) import TcClassDcl ( tcMethodBind, badMethodErr ) -import TcMonad -import RnMonad ( RnNameSupply ) -import Inst ( Inst, InstOrigin(..), - newDicts, LIE, emptyLIE, plusLIE, plusLIEs ) +import TcMonad +import Inst ( InstOrigin(..), + newDicts, newClassDicts, + LIE, emptyLIE, plusLIE, plusLIEs ) import TcDeriv ( tcDeriving ) -import TcEnv ( tcExtendGlobalValEnv, tcAddImportedIdInfo ) -import TcInstUtil ( InstInfo(..), mkInstanceRelatedIds, classDataCon ) -import TcKind ( TcKind, unifyKind ) -import TcMonoType ( tcHsType ) +import TcEnv ( TcEnv, tcExtendGlobalValEnv, + tcExtendTyVarEnvForMeths, + tcAddImportedIdInfo, tcInstId, tcLookupClass, + InstInfo(..), pprInstInfo, simpleInstInfoTyCon, simpleInstInfoTy, + newDFunName, tcExtendTyVarEnv + ) +import InstEnv ( InstEnv, extendInstEnv ) +import TcMonoType ( tcTyVars, tcHsSigType, kcHsSigType ) import TcSimplify ( tcSimplifyAndCheck ) -import TcType ( TcType, TcTyVar, TcTyVarSet, - zonkSigTyVar, tcInstSigTyVars, tcInstType, tcInstTheta +import TcType ( zonkTcSigTyVars ) +import HscTypes ( HomeSymbolTable, DFunId, + ModDetails(..), PackageInstEnv, PersistentRenamerState ) -import Bag ( emptyBag, unitBag, unionBags, unionManyBags, - foldBag, bagToList, Bag - ) -import CmdLineOpts ( opt_GlasgowExts, opt_WarnMissingMethods ) -import Class ( classBigSig, Class ) -import Id ( isNullaryDataCon, dataConArgTys, replaceIdInfo, idName, Id ) -import Maybes ( maybeToBool, seqMaybe, catMaybes ) -import Name ( nameOccName, mkLocalName, - isLocallyDefined, Module, - NamedThing(..) +import Bag ( unionManyBags ) +import DataCon ( classDataCon ) +import Class ( Class, DefMeth(..), classBigSig ) +import Var ( idName, idType ) +import Maybes ( maybeToBool ) +import MkId ( mkDictFunId ) +import Generics ( validGenericInstanceType ) +import Module ( Module, foldModuleEnv ) +import Name ( getSrcLoc ) +import NameSet ( emptyNameSet, nameSetToList ) +import PrelInfo ( eRROR_ID ) +import PprType ( pprConstraint, pprPred ) +import TyCon ( TyCon, isSynTyCon ) +import Type ( splitDFunTy, isTyVarTy, + splitTyConApp_maybe, splitDictTy, + splitForAllTys, + tyVarsOfTypes, mkClassPred, mkTyVarTy, + getClassTys_maybe ) -import PrelVals ( nO_METHOD_BINDING_ERROR_ID, eRROR_ID ) -import PprType ( pprParendType, pprConstraint ) -import SrcLoc ( SrcLoc, noSrcLoc ) -import TyCon ( isSynTyCon, isDataTyCon, tyConDerivings ) -import Type ( Type, ThetaType, isUnpointedType, - splitSigmaTy, isTyVarTy, mkSigmaTy, - splitTyConApp_maybe, splitDictTy_maybe, - splitAlgTyConApp_maybe, splitRhoTy, - tyVarsOfTypes +import Subst ( mkTopTyVarSubst, substClasses ) +import VarSet ( mkVarSet, varSetElems ) +import TysWiredIn ( genericTyCons, isFFIArgumentTy, isFFIImportResultTy ) +import PrelNames ( cCallableClassKey, cReturnableClassKey, hasKey ) +import Name ( Name ) +import SrcLoc ( SrcLoc ) +import VarSet ( varSetElems ) +import Unique ( Uniquable(..) ) +import BasicTypes ( NewOrData(..), Fixity ) +import ErrUtils ( dumpIfSet_dyn ) +import ListSetOps ( Assoc, emptyAssoc, plusAssoc_C, mapAssoc, + assocElts, extendAssoc_C, + equivClassesByUniq, minusList ) -import TyVar ( zipTyVarEnv, mkTyVarSet, tyVarSetToList, TyVar ) -import TysPrim ( byteArrayPrimTyCon, mutableByteArrayPrimTyCon ) -import TysWiredIn ( stringTy ) -import Unique ( Unique, cCallableClassKey, cReturnableClassKey, Uniquable(..) ) +import List ( partition ) import Outputable \end{code} @@ -143,63 +151,262 @@ Here, Bop1 \ldots Bopn bind the methods op1 \ldots opn, and $dbinds_super$ bind the superclass dictionaries sd1 \ldots sdm. \end{enumerate} + +%************************************************************************ +%* * +\subsection{Extracting instance decls} +%* * +%************************************************************************ + +Gather up the instance declarations from their various sources + \begin{code} -tcInstDecls1 :: TcEnv s -- Contains IdInfo for dfun ids +tcInstDecls1 :: PackageInstEnv + -> PersistentRenamerState + -> HomeSymbolTable -- Contains instances + -> TcEnv -- Contains IdInfo for dfun ids + -> (Name -> Maybe Fixity) -- for deriving Show and Read + -> Module -- Module for deriving -> [RenamedHsDecl] - -> Module -- module name for deriving - -> RnNameSupply -- for renaming derivings - -> TcM s (Bag InstInfo, - RenamedHsBinds, - SDoc) - -tcInstDecls1 unf_env decls mod_name rn_name_supply - = -- Do the ordinary instance declarations - mapNF_Tc (tcInstDecl1 unf_env mod_name) - [inst_decl | InstD inst_decl <- decls] `thenNF_Tc` \ inst_info_bags -> - let - decl_inst_info = unionManyBags inst_info_bags + -> TcM (PackageInstEnv, InstEnv, [InstInfo], RenamedHsBinds) + +tcInstDecls1 inst_env0 prs hst unf_env get_fixity mod decls + = let + inst_decls = [inst_decl | InstD inst_decl <- decls] + tycl_decls = [decl | TyClD decl <- decls] + clas_decls = filter isClassDecl tycl_decls in - -- Handle "derived" instances; note that we only do derivings - -- for things in this module; we ignore deriving decls from - -- interfaces! - tcDeriving mod_name rn_name_supply decl_inst_info - `thenTc` \ (deriv_inst_info, deriv_binds, ddump_deriv) -> + -- (1) Do the ordinary instance declarations + mapNF_Tc (tcInstDecl1 unf_env) inst_decls `thenNF_Tc` \ inst_infos -> + + -- (2) Instances from generic class declarations + getGenericInstances clas_decls `thenTc` \ generic_inst_info -> + + -- Next, construct the instance environment so far, consisting of + -- a) cached non-home-package InstEnv (gotten from pcs) pcs_insts pcs + -- b) imported instance decls (not in the home package) inst_env1 + -- c) other modules in this package (gotten from hst) inst_env2 + -- d) local instance decls inst_env3 + -- e) generic instances inst_env4 + -- The result of (b) replaces the cached InstEnv in the PCS + let + (local_inst_info, imported_inst_info) = partition iLocal (concat inst_infos) + imported_dfuns = map (tcAddImportedIdInfo unf_env . iDFunId) + imported_inst_info + hst_dfuns = foldModuleEnv ((++) . md_insts) [] hst + in + 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 -> + addInstInfos inst_env3 generic_inst_info `thenNF_Tc` \ inst_env4 -> + + -- (3) Compute instances from "deriving" clauses; + -- note that we only do derivings for things in this module; + -- we ignore deriving decls from interfaces! + -- This stuff computes a context for the derived instance decl, so it + -- needs to know about all the instances possible; hecne inst_env4 + tcDeriving prs mod inst_env4 get_fixity tycl_decls `thenTc` \ (deriv_inst_info, deriv_binds) -> + addInstInfos inst_env4 deriv_inst_info `thenNF_Tc` \ final_inst_env -> + + returnTc (inst_env1, + final_inst_env, + generic_inst_info ++ deriv_inst_info ++ local_inst_info, + deriv_binds) + +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 + = getDOptsTc `thenTc` \ dflags -> let - full_inst_info = deriv_inst_info `unionBags` decl_inst_info + (inst_env', errs) = extendInstEnv dflags dfuns infos in - returnTc (full_inst_info, deriv_binds, ddump_deriv) - + addErrsTc errs `thenNF_Tc_` + returnTc inst_env' +\end{code} -tcInstDecl1 :: TcEnv s -> Module -> RenamedInstDecl -> NF_TcM s (Bag InstInfo) - -tcInstDecl1 unf_env mod_name (InstDecl poly_ty binds uprags (Just dfun_name) src_loc) +\begin{code} +tcInstDecl1 :: TcEnv -> RenamedInstDecl -> NF_TcM [InstInfo] +-- Deal with a single instance declaration +tcInstDecl1 unf_env (InstDecl poly_ty binds uprags maybe_dfun_name src_loc) = -- Prime error recovery, set source location - recoverNF_Tc (returnNF_Tc emptyBag) $ + recoverNF_Tc (returnNF_Tc []) $ tcAddSrcLoc src_loc $ -- Type-check all the stuff before the "where" - tcHsType poly_ty `thenTc` \ poly_ty' -> + tcHsSigType poly_ty `thenTc` \ poly_ty' -> let - (tyvars, theta, dict_ty) = splitSigmaTy poly_ty' - (clas, inst_tys) = case splitDictTy_maybe dict_ty of - Nothing -> pprPanic "tcInstDecl1" (ppr poly_ty) - Just pair -> pair + (tyvars, theta, clas, inst_tys) = splitDFunTy poly_ty' in - -- Check for respectable instance type - scrutiniseInstanceType clas inst_tys `thenTc_` + (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 -> + scrutiniseInstanceHead dflags clas inst_tys `thenNF_Tc_` + mapNF_Tc (scrutiniseInstanceConstraint dflags) theta `thenNF_Tc_` + + -- Make the dfun id and return it + newDFunName clas inst_tys src_loc `thenNF_Tc` \ dfun_name -> + returnNF_Tc (True, dfun_name) + + Just dfun_name -> -- An interface-file instance declaration + -- Make the dfun id + returnNF_Tc (False, dfun_name) + ) `thenNF_Tc` \ (is_local, dfun_name) -> - -- Make the dfun id and constant-method ids let - (dfun_id, dfun_theta) = mkInstanceRelatedIds dfun_name - clas tyvars inst_tys theta - -- Add info from interface file - final_dfun_id = tcAddImportedIdInfo unf_env dfun_id + dfun_id = mkDictFunId dfun_name clas tyvars inst_tys theta in - returnTc (unitBag (InstInfo clas tyvars inst_tys theta - dfun_theta final_dfun_id - binds src_loc uprags)) + returnTc [InstInfo { iLocal = is_local, iDFunId = dfun_id, + iBinds = binds, iPrags = uprags }] +\end{code} + + +%************************************************************************ +%* * +\subsection{Extracting generic instance declaration from class declarations} +%* * +%************************************************************************ + +@getGenericInstances@ extracts the generic instance declarations from a class +declaration. For exmaple + + class C a where + op :: a -> a + + op{ x+y } (Inl v) = ... + op{ x+y } (Inr v) = ... + op{ x*y } (v :*: w) = ... + op{ 1 } Unit = ... + +gives rise to the instance declarations + + instance C (x+y) where + op (Inl v) = ... + op (Inr v) = ... + + instance C (x*y) where + op (v :*: w) = ... + + instance C 1 where + op Unit = ... + + +\begin{code} +getGenericInstances :: [RenamedTyClDecl] -> TcM [InstInfo] +getGenericInstances class_decls + = mapTc get_generics class_decls `thenTc` \ gen_inst_infos -> + let + gen_inst_info = concat gen_inst_infos + in + getDOptsTc `thenTc` \ dflags -> + ioToTc (dumpIfSet_dyn dflags Opt_D_dump_deriv "Generic instances" + (vcat (map pprInstInfo gen_inst_info))) + `thenNF_Tc_` + returnTc gen_inst_info + +get_generics decl@(ClassDecl {tcdMeths = Nothing}) + = returnTc [] -- Imported class decls + +get_generics decl@(ClassDecl {tcdName = class_name, tcdMeths = Just def_methods, tcdLoc = loc}) + | null groups + = returnTc [] -- The comon case: no generic default methods + + | otherwise -- A local class decl with generic default methods + = recoverNF_Tc (returnNF_Tc []) $ + tcAddDeclCtxt decl $ + tcLookupClass class_name `thenTc` \ clas -> + + -- Make an InstInfo out of each group + mapTc (mkGenericInstance clas loc) groups `thenTc` \ inst_infos -> + + -- Check that there is only one InstInfo for each type constructor + -- The main way this can fail is if you write + -- f {| a+b |} ... = ... + -- f {| x+y |} ... = ... + -- Then at this point we'll have an InstInfo for each + let + tc_inst_infos :: [(TyCon, InstInfo)] + tc_inst_infos = [(simpleInstInfoTyCon i, i) | i <- inst_infos] + + bad_groups = [group | group <- equivClassesByUniq get_uniq tc_inst_infos, + length group > 1] + get_uniq (tc,_) = getUnique tc + in + mapTc (addErrTc . dupGenericInsts) bad_groups `thenTc_` + + -- Check that there is an InstInfo for each generic type constructor + let + missing = genericTyCons `minusList` [tc | (tc,_) <- tc_inst_infos] + in + checkTc (null missing) (missingGenericInstances missing) `thenTc_` + + returnTc inst_infos + + where + -- Group the declarations by type pattern + groups :: [(RenamedHsType, RenamedMonoBinds)] + groups = assocElts (getGenericBinds def_methods) + + +--------------------------------- +getGenericBinds :: RenamedMonoBinds -> Assoc RenamedHsType RenamedMonoBinds + -- Takes a group of method bindings, finds the generic ones, and returns + -- them in finite map indexed by the type parameter in the definition. + +getGenericBinds EmptyMonoBinds = emptyAssoc +getGenericBinds (AndMonoBinds m1 m2) + = plusAssoc_C AndMonoBinds (getGenericBinds m1) (getGenericBinds m2) + +getGenericBinds (FunMonoBind id infixop matches loc) + = mapAssoc wrap (foldl add emptyAssoc matches) + -- Using foldl not foldr is vital, else + -- we reverse the order of the bindings! + where + add env match = case maybeGenericMatch match of + Nothing -> env + Just (ty, match') -> extendAssoc_C (++) env (ty, [match']) + + wrap ms = FunMonoBind id infixop ms loc + +--------------------------------- +mkGenericInstance :: Class -> SrcLoc + -> (RenamedHsType, RenamedMonoBinds) + -> TcM InstInfo + +mkGenericInstance clas loc (hs_ty, binds) + -- Make a generic instance declaration + -- 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 $ + + -- Type-check the instance type, and check its form + tcHsSigType hs_ty `thenTc` \ inst_ty -> + checkTc (validGenericInstanceType inst_ty) + (badGenericInstanceType binds) `thenTc_` + + -- Make the dictionary function. + newDFunName clas [inst_ty] loc `thenNF_Tc` \ dfun_name -> + let + inst_theta = [mkClassPred clas [mkTyVarTy tv] | tv <- tyvars] + inst_tys = [inst_ty] + dfun_id = mkDictFunId dfun_name clas tyvars inst_tys inst_theta + in + + returnTc (InstInfo { iLocal = True, iDFunId = dfun_id, + iBinds = binds, iPrags = [] }) \end{code} @@ -210,11 +417,13 @@ tcInstDecl1 unf_env mod_name (InstDecl poly_ty binds uprags (Just dfun_name) src %************************************************************************ \begin{code} -tcInstDecls2 :: Bag InstInfo - -> NF_TcM s (LIE s, TcMonoBinds s) +tcInstDecls2 :: [InstInfo] + -> NF_TcM (LIE, TcMonoBinds) tcInstDecls2 inst_decls - = foldBag combine tcInstDecl2 (returnNF_Tc (emptyLIE, EmptyMonoBinds)) inst_decls +-- = foldBag combine tcInstDecl2 (returnNF_Tc (emptyLIE, EmptyMonoBinds)) inst_decls + = foldr combine (returnNF_Tc (emptyLIE, EmptyMonoBinds)) + (map tcInstDecl2 inst_decls) where combine tc1 tc2 = tc1 `thenNF_Tc` \ (lie1, binds1) -> tc2 `thenNF_Tc` \ (lie2, binds2) -> @@ -222,7 +431,6 @@ tcInstDecls2 inst_decls binds1 `AndMonoBinds` binds2) \end{code} - ======= New documentation starts here (Sept 92) ============== The main purpose of @tcInstDecl2@ is to return a @HsBinds@ which defines @@ -290,85 +498,75 @@ is the @dfun_theta@ below. First comes the easy case of a non-local instance decl. \begin{code} -tcInstDecl2 :: InstInfo -> NF_TcM s (LIE s, TcMonoBinds s) +tcInstDecl2 :: InstInfo -> NF_TcM (LIE, TcMonoBinds) -tcInstDecl2 (InstInfo clas inst_tyvars inst_tys - inst_decl_theta dfun_theta - dfun_id monobinds - locn uprags) - | not (isLocallyDefined dfun_id) +tcInstDecl2 (InstInfo { iLocal = is_local, iDFunId = dfun_id, + iBinds = monobinds, iPrags = uprags }) + | not is_local = returnNF_Tc (emptyLIE, EmptyMonoBinds) -{- - -- I deleted this "optimisation" because when importing these - -- instance decls the renamer would look for the dfun bindings and they weren't there. - -- This would be fixable, but it seems simpler just to produce a tiny void binding instead, - -- even though it's never used. - - -- This case deals with CCallable etc, which don't need any bindings - | isNoDictClass clas - = returnNF_Tc (emptyLIE, EmptyBinds) --} - | otherwise = -- Prime error recovery recoverNF_Tc (returnNF_Tc (emptyLIE, EmptyMonoBinds)) $ - tcAddSrcLoc locn $ - - -- Get the class signature - let - origin = InstanceDeclOrigin - (class_tyvars, - sc_theta, sc_sel_ids, - op_sel_ids, defm_ids) = classBigSig clas - in - + tcAddSrcLoc (getSrcLoc dfun_id) $ + -- Instantiate the instance decl with tc-style type variables - tcInstSigTyVars inst_tyvars `thenNF_Tc` \ (inst_tyvars', _, tenv) -> - mapNF_Tc (tcInstType tenv) inst_tys `thenNF_Tc` \ inst_tys' -> - tcInstTheta tenv dfun_theta `thenNF_Tc` \ dfun_theta' -> - tcInstTheta tenv inst_decl_theta `thenNF_Tc` \ inst_decl_theta' -> + tcInstId dfun_id `thenNF_Tc` \ (inst_tyvars', dfun_theta', dict_ty') -> + let + (clas, inst_tys') = splitDictTy dict_ty' + origin = InstanceDeclOrigin - -- Instantiate the super-class context with inst_tys - tcInstTheta (zipTyVarEnv class_tyvars inst_tys') sc_theta `thenNF_Tc` \ sc_theta' -> + (class_tyvars, sc_theta, _, op_items) = classBigSig clas - -- Create dictionary Ids from the specified instance contexts. - newDicts origin sc_theta' `thenNF_Tc` \ (sc_dicts, sc_dict_ids) -> - newDicts origin dfun_theta' `thenNF_Tc` \ (dfun_arg_dicts, dfun_arg_dicts_ids) -> - newDicts origin inst_decl_theta' `thenNF_Tc` \ (inst_decl_dicts, _) -> - newDicts origin [(clas,inst_tys')] `thenNF_Tc` \ (this_dict, [this_dict_id]) -> + dm_ids = [dm_id | (_, DefMeth dm_id) <- op_items] + sel_names = [idName sel_id | (sel_id, _) <- op_items] - -- Check that all the method bindings come from this class - let - check_from_this_class (bndr, loc) - | nameOccName bndr `elem` sel_names = returnNF_Tc () - | otherwise = tcAddSrcLoc loc $ - addErrTc (badMethodErr bndr clas) - sel_names = map getOccName op_sel_ids - bndrs = bagToList (collectMonoBinders monobinds) + -- Instantiate the super-class context with inst_tys + sc_theta' = substClasses (mkTopTyVarSubst class_tyvars inst_tys') sc_theta + + -- 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 - mapNF_Tc check_from_this_class bndrs `thenNF_Tc_` + -- Check that all the method bindings come from this class + mapTc (addErrTc . badMethodErr clas) bad_bndrs `thenNF_Tc_` - tcExtendGlobalValEnv (catMaybes defm_ids) ( + -- Create dictionary Ids from the specified instance contexts. + newClassDicts origin sc_theta' `thenNF_Tc` \ (sc_dicts, sc_dict_ids) -> + newDicts origin dfun_theta' `thenNF_Tc` \ (dfun_arg_dicts, dfun_arg_dicts_ids) -> + newClassDicts origin [(clas,inst_tys')] `thenNF_Tc` \ (this_dict, [this_dict_id]) -> + tcExtendTyVarEnvForMeths inst_tyvars inst_tyvars' ( + tcExtendGlobalValEnv dm_ids ( -- Default-method Ids may be mentioned in synthesised RHSs - mapAndUnzip3Tc (tcInstMethodBind clas inst_tys' inst_tyvars' monobinds uprags) - (op_sel_ids `zip` defm_ids) - ) `thenTc` \ (method_binds_s, insts_needed_s, meth_lies_w_ids) -> - -- Deal with SPECIALISE instance pragmas + mapAndUnzip3Tc (tcMethodBind clas origin inst_tyvars' inst_tys' + dfun_theta' + monobinds uprags True) + op_items + )) `thenTc` \ (method_binds_s, insts_needed_s, meth_lies_w_ids) -> + + -- Deal with SPECIALISE instance pragmas by making them + -- look like SPECIALISE pragmas for the dfun let - dfun_prags = [Sig (idName dfun_id) ty loc | SpecInstSig ty loc <- uprags] + dfun_prags = [SpecSig (idName dfun_id) ty loc | SpecInstSig ty loc <- uprags] in tcExtendGlobalValEnv [dfun_id] ( - tcPragmaSigs dfun_prags - ) `thenTc` \ (prag_info_fn, prag_binds, prag_lie) -> + tcSpecSigs dfun_prags + ) `thenTc` \ (prag_binds, prag_lie) -> -- Check the overloading constraints of the methods and superclasses - mapNF_Tc zonkSigTyVar inst_tyvars' `thenNF_Tc` \ zonked_inst_tyvars -> + -- 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 inst_tyvars' `thenNF_Tc` \ zonked_inst_tyvars -> let - inst_tyvars_set = mkTyVarSet zonked_inst_tyvars + inst_tyvars_set = mkVarSet zonked_inst_tyvars (meth_lies, meth_ids) = unzip meth_lies_w_ids @@ -381,40 +579,24 @@ tcInstDecl2 (InstInfo clas inst_tyvars inst_tys methods_lie = plusLIEs insts_needed_s in - -- Check that we *could* construct the superclass dictionaries, - -- even though we are *actually* going to pass the superclass dicts in; - -- the check ensures that the caller will never have a problem building - -- them. - tcAddErrCtxt superClassCtxt ( - tcSimplifyAndCheck - (ptext SLIT("instance declaration context")) - inst_tyvars_set -- Local tyvars - inst_decl_dicts -- The instance dictionaries available - sc_dicts -- The superclass dicationaries reqd - ) `thenTc_` - -- Ignore the result; we're only doing - -- this to make sure it can be done. - - -- Ditto method bindings + -- Simplify the constraints from methods tcAddErrCtxt methodCtxt ( tcSimplifyAndCheck (ptext SLIT("instance declaration context")) inst_tyvars_set -- Local tyvars avail_insts methods_lie - ) `thenTc_` + ) `thenTc` \ (const_lie1, lie_binds1) -> - -- Now do the simplification again, this time to get the - -- bindings; this time we use an enhanced "avails" - -- Ignore errors because they come from the *previous* tcSimplifys - discardErrsTc ( - tcSimplifyAndCheck + -- Figure out bindings for the superclass context + tcAddErrCtxt superClassCtxt ( + tcSimplifyAndCheck (ptext SLIT("instance declaration context")) inst_tyvars_set dfun_arg_dicts -- NB! Don't include this_dict here, else the sc_dicts -- get bound by just selecting from this_dict!! - (sc_dicts `plusLIE` methods_lie `plusLIE` prag_lie) - ) `thenTc` \ (const_lie, lie_binds) -> + sc_dicts + ) `thenTc` \ (const_lie2, lie_binds2) -> -- Create the result bindings @@ -430,115 +612,47 @@ tcInstDecl2 (InstInfo clas inst_tyvars inst_tys -- emit an error message. This in turn means that we don't -- mention the constructor, which doesn't exist for CCallable, CReturnable -- Hardly beautiful, but only three extra lines. - HsApp (TyApp (HsVar (RealId eRROR_ID)) [tcIdType this_dict_id]) - (HsLitOut (HsString msg) stringTy) + HsApp (TyApp (HsVar eRROR_ID) [idType this_dict_id]) + (HsLit (HsString msg)) | otherwise -- The common case - = foldl HsApp (TyApp (HsVar (RealId dict_constr)) inst_tys') - (map HsVar (sc_dict_ids ++ meth_ids)) + = mkHsConApp dict_constr inst_tys' (map HsVar (sc_dict_ids ++ meth_ids)) -- We don't produce a binding for the dict_constr; instead we -- rely on the simplifier to unfold this saturated application + -- We do this rather than generate an HsCon directly, because + -- it means that the special cases (e.g. dictionary with only one + -- member) are dealt with by the common MkId.mkDataConWrapId code rather + -- than needing to be repeated here. + where msg = _PK_ ("Compiler error: bad dictionary " ++ showSDoc (ppr clas)) dict_bind = VarMonoBind this_dict_id dict_rhs - method_binds = andMonoBinds method_binds_s + method_binds = andMonoBindList method_binds_s - final_dfun_id = replaceIdInfo dfun_id (prag_info_fn (idName dfun_id)) - -- Pretty truesome main_bind = AbsBinds zonked_inst_tyvars dfun_arg_dicts_ids - [(inst_tyvars', RealId final_dfun_id, this_dict_id)] - (lie_binds `AndMonoBinds` + [(inst_tyvars', dfun_id, this_dict_id)] + emptyNameSet -- No inlines (yet) + (lie_binds1 `AndMonoBinds` + lie_binds2 `AndMonoBinds` method_binds `AndMonoBinds` - prag_binds `AndMonoBinds` dict_bind) in - returnTc (const_lie, + returnTc (const_lie1 `plusLIE` const_lie2 `plusLIE` prag_lie, main_bind `AndMonoBinds` prag_binds) \end{code} %************************************************************************ %* * -\subsection{Processing each method} -%* * -%************************************************************************ - -\begin{code} -tcInstMethodBind - :: Class - -> [TcType s] -- Instance types - -> [TcTyVar s] -- and their free (sig) tyvars - -> RenamedMonoBinds -- Method binding - -> [RenamedSig] -- Pragmas - -> (Id, Maybe Id) -- Selector id and default-method id - -> TcM s (TcMonoBinds s, LIE s, (LIE s, TcIdOcc s)) - -tcInstMethodBind clas inst_tys inst_tyvars meth_binds prags (sel_id, maybe_dm_id) - = tcGetSrcLoc `thenNF_Tc` \ loc -> - tcGetUnique `thenNF_Tc` \ uniq -> - let - sel_name = idName sel_id - meth_occ = getOccName sel_name - default_meth_name = mkLocalName uniq meth_occ loc - maybe_meth_bind = find sel_name meth_binds - the_meth_bind = case maybe_meth_bind of - Just stuff -> stuff - Nothing -> mk_default_bind default_meth_name loc - meth_prags = sigsForMe (== sel_name) prags - in - - -- Warn if no method binding, only if -fwarn-missing-methods - - warnTc (opt_WarnMissingMethods && - not (maybeToBool maybe_meth_bind) && - not (maybeToBool maybe_dm_id)) - (omittedMethodWarn sel_id clas) `thenNF_Tc_` - - -- Typecheck the method binding - tcMethodBind clas origin inst_tys inst_tyvars sel_id the_meth_bind meth_prags - where - origin = InstanceDeclOrigin -- Poor - - find sel EmptyMonoBinds = Nothing - find sel (AndMonoBinds b1 b2) = find sel b1 `seqMaybe` find sel b2 - - find sel b@(FunMonoBind op_name _ _ _) | op_name == sel = Just b - | otherwise = Nothing - find sel b@(PatMonoBind (VarPatIn op_name) _ _) | op_name == sel = Just b - | otherwise = Nothing - find sel other = panic "Urk! Bad instance method binding" - - - mk_default_bind local_meth_name loc - = PatMonoBind (VarPatIn local_meth_name) - (GRHSsAndBindsIn (unguardedRHS (default_expr loc) loc) EmptyBinds) - loc - - default_expr loc - = case maybe_dm_id of - Just dm_id -> HsVar (getName dm_id) -- There's a default method - Nothing -> error_expr loc -- No default method - - error_expr loc - = HsApp (HsVar (getName nO_METHOD_BINDING_ERROR_ID)) - (HsLit (HsString (_PK_ (error_msg loc)))) - - error_msg loc = showSDoc (hcat [ppr loc, text "|", ppr sel_id ]) -\end{code} - - - -%************************************************************************ -%* * \subsection{Checking for a decent instance type} %* * %************************************************************************ -@scrutiniseInstanceType@ checks the type {\em and} its syntactic constraints: +@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@ @@ -548,48 +662,54 @@ compiled elsewhere). In these cases, we let them go through anyway. We can also have instances for functions: @instance Foo (a -> b) ...@. \begin{code} -scrutiniseInstanceType clas inst_taus - | -- CCALL CHECK (a).... urgh! - -- To verify that a user declaration of a CCallable/CReturnable - -- instance is OK, we must be able to see the constructor(s) - -- of the instance type (see next guard.) - -- - -- We flag this separately to give a more precise error msg. - -- - (uniqueOf clas == cCallableClassKey || uniqueOf clas == cReturnableClassKey) - && is_alg_tycon_app && not constructors_visible - = failWithTc (invisibleDataConPrimCCallErr clas first_inst_tau) - - | -- CCALL CHECK (b) +scrutiniseInstanceConstraint dflags pred + | dopt Opt_AllowUndecidableInstances dflags + = returnNF_Tc () + + | Just (clas,tys) <- getClassTys_maybe pred, + all isTyVarTy tys + = returnNF_Tc () + + | otherwise + = addErrTc (instConstraintErr pred) + +scrutiniseInstanceHead dflags clas inst_taus + | -- CCALL CHECK -- A user declaration of a CCallable/CReturnable instance -- must be for a "boxed primitive" type. - (uniqueOf clas == cCallableClassKey && not (ccallable_type first_inst_tau)) || - (uniqueOf clas == cReturnableClassKey && not (creturnable_type first_inst_tau)) - = failWithTc (nonBoxedPrimCCallErr clas first_inst_tau) - - -- DERIVING CHECK - -- It is obviously illegal to have an explicit instance - -- for something that we are also planning to `derive' - | maybeToBool alg_tycon_app_maybe && clas `elem` (tyConDerivings alg_tycon) - = failWithTc (derivingWhenInstanceExistsErr clas first_inst_tau) - -- Kind check will have ensured inst_taus is of length 1 + (clas `hasKey` cCallableClassKey + && not (ccallable_type dflags first_inst_tau)) + || + (clas `hasKey` cReturnableClassKey + && not (creturnable_type first_inst_tau)) + = addErrTc (nonBoxedPrimCCallErr clas first_inst_tau) + + -- Allow anything for AllowUndecidableInstances + | dopt Opt_AllowUndecidableInstances dflags + = returnNF_Tc () + + -- If GlasgowExts then check at least one isn't a type variable + | dopt Opt_GlasgowExts dflags + = if all isTyVarTy inst_taus + then addErrTc (instTypeErr clas inst_taus + (text "There must be at least one non-type-variable in the instance head")) + else returnNF_Tc () -- WITH HASKELL 1.4, MUST HAVE C (T a b c) - | not opt_GlasgowExts - && not (length inst_taus == 1 && - maybeToBool maybe_tycon_app && -- Yes, there's a type constuctor + | 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 (tyVarSetToList (tyVarsOfTypes arg_tys)) == length arg_tys - -- This last condition checks that all the type variables are distinct - ) - = failWithTc (instTypeErr clas inst_taus - (text "the instance type must be of form (T a b c)" $$ - text "where T is not a synonym, and a,b,c are distinct type variables") - ) + length (varSetElems (tyVarsOfTypes arg_tys)) == length arg_tys + -- This last condition checks that all the type variables are distinct + ) + = addErrTc (instTypeErr clas inst_taus + (text "the instance type must be of form (T a b c)" $$ + text "where T is not a synonym, and a,b,c are distinct type variables") + ) | otherwise - = returnTc () + = returnNF_Tc () where (first_inst_tau : _) = inst_taus @@ -598,80 +718,67 @@ scrutiniseInstanceType clas inst_taus maybe_tycon_app = splitTyConApp_maybe first_inst_tau Just (tycon, arg_tys) = maybe_tycon_app - -- Stuff for an *algebraic* data type - alg_tycon_app_maybe = splitAlgTyConApp_maybe first_inst_tau - -- The "Alg" part looks through synonyms - is_alg_tycon_app = maybeToBool alg_tycon_app_maybe - Just (alg_tycon, _, data_cons) = alg_tycon_app_maybe + ccallable_type dflags ty = isFFIArgumentTy dflags False {- Not safe call -} ty + creturnable_type ty = isFFIImportResultTy dflags ty +\end{code} - constructors_visible = not (null data_cons) - --- These conditions come directly from what the DsCCall is capable of. --- Totally grotesque. Green card should solve this. +%************************************************************************ +%* * +\subsection{Error messages} +%* * +%************************************************************************ -ccallable_type ty = isUnpointedType ty || -- Allow CCallable Int# etc - maybeToBool (maybeBoxedPrimType ty) || -- Ditto Int etc - ty == stringTy || - byte_arr_thing +\begin{code} +tcAddDeclCtxt decl thing_inside + = tcAddSrcLoc (tcdLoc decl) $ + tcAddErrCtxt ctxt $ + thing_inside where - byte_arr_thing = case splitAlgTyConApp_maybe ty of - Just (tycon, ty_args, [data_con]) | isDataTyCon tycon -> - length data_con_arg_tys == 2 && - maybeToBool maybe_arg2_tycon && - (arg2_tycon == byteArrayPrimTyCon || - arg2_tycon == mutableByteArrayPrimTyCon) - where - data_con_arg_tys = dataConArgTys data_con ty_args - (data_con_arg_ty1 : data_con_arg_ty2 : _) = data_con_arg_tys - maybe_arg2_tycon = splitTyConApp_maybe data_con_arg_ty2 - Just (arg2_tycon,_) = maybe_arg2_tycon - - other -> False - -creturnable_type ty = maybeToBool (maybeBoxedPrimType ty) || - -- Or, a data type with a single nullary constructor - case (splitAlgTyConApp_maybe ty) of - Just (tycon, tys_applied, [data_con]) - -> isNullaryDataCon data_con - other -> False + thing = case decl of + ClassDecl {} -> "class" + TySynonym {} -> "type synonym" + TyData {tcdND = NewType} -> "newtype" + TyData {tcdND = DataType} -> "data type" + + ctxt = hsep [ptext SLIT("In the"), text thing, + ptext SLIT("declaration for"), quotes (ppr (tcdName decl))] \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)] + +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)), + ptext SLIT("All the type patterns for a generic type constructor must be identical") + ] + where + ppr_inst_ty (tc,inst) = ppr (simpleInstInfoTy inst) instTypeErr clas tys msg = sep [ptext SLIT("Illegal instance declaration for") <+> quotes (pprConstraint clas tys), nest 4 (parens msg) ] -derivingWhenInstanceExistsErr clas tycon - = hang (hsep [ptext SLIT("Deriving class"), - quotes (ppr clas), - ptext SLIT("type"), quotes (ppr tycon)]) - 4 (ptext SLIT("when an explicit instance exists")) - nonBoxedPrimCCallErr clas inst_ty = hang (ptext SLIT("Unacceptable instance type for ccall-ish class")) 4 (hsep [ ptext SLIT("class"), ppr clas, ptext SLIT("type"), ppr inst_ty]) -omittedMethodWarn sel_id clas - = sep [ptext SLIT("No explicit method nor default method for") <+> quotes (ppr sel_id), - ptext SLIT("in an instance declaration for") <+> quotes (ppr clas)] - -{- - Declaring CCallable & CReturnable instances in a module different - from where the type was defined. Caused by importing data type - abstractly (either programmatically or by the renamer being over-eager - in its pruning.) --} -invisibleDataConPrimCCallErr clas inst_ty - = hang (hsep [ptext SLIT("Constructors for"), quotes (ppr inst_ty), - ptext SLIT("not visible when checking"), - quotes (ppr clas), ptext SLIT("instance")]) - 4 (hsep [text "(Try either importing", ppr inst_ty, - text "non-abstractly or compile using -fno-prune-tydecls ..)"]) - methodCtxt = ptext SLIT("When checking the methods of an instance declaration") -superClassCtxt = ptext SLIT("When checking the superclasses of an instance declaration") +superClassCtxt = ptext SLIT("When checking the super-classes of an instance declaration") \end{code}