X-Git-Url: http://git.megacz.com/?p=ghc-hetmet.git;a=blobdiff_plain;f=compiler%2Ftypecheck%2FTcClassDcl.lhs;h=839a5a276b999810597512b152e4e000d22d707d;hp=0fb82cb76a305eafc156c0f1da378b377857e1f1;hb=b10d7d079ec9c3fc22d4700fe484dd297bddb805;hpb=836b1e90821aacc9d1e09fe78085f911597274c8 diff --git a/compiler/typecheck/TcClassDcl.lhs b/compiler/typecheck/TcClassDcl.lhs index 0fb82cb..839a5a2 100644 --- a/compiler/typecheck/TcClassDcl.lhs +++ b/compiler/typecheck/TcClassDcl.lhs @@ -8,7 +8,7 @@ Typechecking class declarations \begin{code} module TcClassDcl ( tcClassSigs, tcClassDecl2, findMethodBind, instantiateMethod, tcInstanceMethodBody, - mkGenericDefMethBind, getGenericInstances, mkDefMethRdrName, + mkGenericDefMethBind, getGenericInstances, tcAddDeclCtxt, badMethodErr, badATErr, omittedATWarn ) where @@ -17,16 +17,17 @@ module TcClassDcl ( tcClassSigs, tcClassDecl2, import HsSyn import RnHsSyn import RnExpr -import RnEnv import Inst import InstEnv +import TcPat( addInlinePrags ) import TcEnv import TcBinds -import TcSimplify +import TcUnify import TcHsType import TcMType import TcType import TcRnMonad +import BuildTyCl( TcMethInfo ) import Generics import Class import TyCon @@ -36,7 +37,6 @@ import Name import Var import NameEnv import NameSet -import RdrName import Outputable import PrelNames import DynFlags @@ -99,54 +99,44 @@ tcClassSigs :: Name -- Name of the class -> LHsBinds Name -> TcM [TcMethInfo] -type TcMethInfo = (Name, DefMeth, Type) -- A temporary intermediate, to communicate - -- between tcClassSigs and buildClass tcClassSigs clas sigs def_methods - = do { dm_env <- checkDefaultBinds clas op_names def_methods - ; mapM (tcClassSig dm_env) op_sigs } + = do { dm_env <- mapM (addLocM (checkDefaultBind clas op_names)) + (bagToList def_methods) + ; mapM (tcClassSig (mkNameEnv dm_env)) op_sigs } where op_sigs = [sig | sig@(L _ (TypeSig _ _)) <- sigs] op_names = [n | (L _ (TypeSig (L _ n) _)) <- op_sigs] - -checkDefaultBinds :: Name -> [Name] -> LHsBinds Name -> TcM (NameEnv Bool) +checkDefaultBind :: Name -> [Name] -> HsBindLR Name Name -> TcM (Name, DefMethSpec) -- 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 Bool - -- where True <=> it's a generic default method -checkDefaultBinds clas ops binds - = do dm_infos <- mapM (addLocM (checkDefaultBind clas ops)) (bagToList binds) - return (mkNameEnv dm_infos) - -checkDefaultBind :: Name -> [Name] -> HsBindLR Name Name -> TcM (Name, Bool) checkDefaultBind clas ops (FunBind {fun_id = L _ op, fun_matches = MatchGroup matches _ }) = do { -- Check that the op is from this class - checkTc (op `elem` ops) (badMethodErr clas op) + checkTc (op `elem` ops) (badMethodErr clas op) -- Check that all the defns ar generic, or none are - ; checkTc (all_generic || none_generic) (mixedGenericErr op) - - ; return (op, all_generic) + ; case (none_generic, all_generic) of + (True, _) -> return (op, VanillaDM) + (_, True) -> return (op, GenericDM) + _ -> failWith (mixedGenericErr op) } where n_generic = count (isJust . maybeGenericMatch) matches none_generic = n_generic == 0 all_generic = matches `lengthIs` n_generic + checkDefaultBind _ _ b = pprPanic "checkDefaultBind" (ppr b) -tcClassSig :: NameEnv Bool -- Info about default methods; +tcClassSig :: NameEnv DefMethSpec -- Info about default methods; -> LSig Name -> TcM TcMethInfo tcClassSig dm_env (L loc (TypeSig (L _ op_name) op_hs_ty)) = setSrcSpan loc $ do { op_ty <- tcHsKindedType op_hs_ty -- Class tyvars already in scope - ; let dm = case lookupNameEnv dm_env op_name of - Nothing -> NoDefMeth - Just False -> DefMeth - Just True -> GenDefMeth + ; let dm = lookupNameEnv dm_env op_name `orElse` NoDM ; return (op_name, dm, op_ty) } tcClassSig _ s = pprPanic "tcClassSig" (ppr s) \end{code} @@ -160,12 +150,12 @@ tcClassSig _ s = pprPanic "tcClassSig" (ppr s) \begin{code} tcClassDecl2 :: LTyClDecl Name -- The class declaration - -> TcM ([Id], LHsBinds Id) + -> TcM (LHsBinds Id) tcClassDecl2 (L loc (ClassDecl {tcdLName = class_name, tcdSigs = sigs, tcdMeths = default_binds})) - = recoverM (return ([], emptyLHsBinds)) $ - setSrcSpan loc $ + = recoverM (return emptyLHsBinds) $ + setSrcSpan loc $ do { clas <- tcLookupLocatedClass class_name -- We make a separate binding for each default method. @@ -180,111 +170,113 @@ tcClassDecl2 (L loc (ClassDecl {tcdLName = class_name, tcdSigs = sigs, (tyvars, _, _, op_items) = classBigSig clas rigid_info = ClsSkol clas prag_fn = mkPragFun sigs default_binds - sig_fn = mkTcSigFun sigs + sig_fn = mkSigFun sigs clas_tyvars = tcSkolSigTyVars rigid_info tyvars pred = mkClassPred clas (mkTyVarTys clas_tyvars) - ; inst_loc <- getInstLoc (SigOrigin rigid_info) - ; this_dict <- newDictBndr inst_loc pred + ; this_dict <- newEvVar pred ; let tc_dm = tcDefMeth clas clas_tyvars this_dict default_binds sig_fn prag_fn - -- tc_dm is called only for a sel_id - -- that has a binding in default_binds - - dm_sel_ids = [sel_id | (sel_id, DefMeth) <- op_items] - -- Generate code for polymorphic default methods only (hence DefMeth) - -- (Generic default methods have turned into instance decls by now.) - -- This is incompatible with Hugs, which expects a polymorphic - -- default method for every class op, regardless of whether or not - -- the programmer supplied an explicit default decl for the class. - -- (If necessary we can fix that, but we don't have a convenient Id to hand.) - ; (dm_ids, defm_binds) <- tcExtendTyVarEnv clas_tyvars $ - mapAndUnzipM tc_dm dm_sel_ids + ; dm_binds <- tcExtendTyVarEnv clas_tyvars $ + mapM tc_dm op_items - ; return (dm_ids, listToBag defm_binds) } + ; return (listToBag (catMaybes dm_binds)) } tcClassDecl2 d = pprPanic "tcClassDecl2" (ppr d) -tcDefMeth :: Class -> [TyVar] -> Inst -> LHsBinds Name - -> TcSigFun -> TcPragFun -> Id - -> TcM (Id, LHsBind Id) -tcDefMeth clas tyvars this_dict binds_in sig_fn prag_fn sel_id - = do { let sel_name = idName sel_id - ; dm_name <- lookupTopBndrRn (mkDefMethRdrName sel_name) - ; local_dm_name <- newLocalName sel_name - -- Base the local_dm_name on the selector name, becuase +tcDefMeth :: Class -> [TyVar] -> EvVar -> LHsBinds Name + -> SigFun -> PragFun -> ClassOpItem + -> TcM (Maybe (LHsBind Id)) +-- Generate code for polymorphic default methods only (hence DefMeth) +-- (Generic default methods have turned into instance decls by now.) +-- This is incompatible with Hugs, which expects a polymorphic +-- default method for every class op, regardless of whether or not +-- the programmer supplied an explicit default decl for the class. +-- (If necessary we can fix that, but we don't have a convenient Id to hand.) +tcDefMeth clas tyvars this_dict binds_in sig_fn prag_fn (sel_id, dm_info) + = case dm_info of + NoDefMeth -> return Nothing + GenDefMeth -> return Nothing + DefMeth dm_name -> do + { let sel_name = idName sel_id + ; local_dm_name <- newLocalName sel_name + -- Base the local_dm_name on the selector name, because -- type errors from tcInstanceMethodBody come from here -- See Note [Silly default-method bind] -- (possibly out of date) - ; let meth_bind = findMethodBind sel_name local_dm_name binds_in + ; let meth_bind = findMethodBind sel_name binds_in `orElse` pprPanic "tcDefMeth" (ppr sel_id) - -- We only call tcDefMeth on selectors for which - -- there is a binding in binds_in + -- dm_info = DefMeth dm_name only if there is a binding in binds_in - dm_sig_fn _ = sig_fn sel_name - dm_ty = idType sel_id - dm_id = mkDefaultMethodId dm_name dm_ty + dm_sig_fn _ = sig_fn sel_name + dm_id = mkDefaultMethodId sel_id dm_name local_dm_type = instantiateMethod clas sel_id (mkTyVarTys tyvars) local_dm_id = mkLocalId local_dm_name local_dm_type + prags = prag_fn sel_name - ; (dm_id_w_inline, spec_prags) - <- tcPrags NonRecursive False True dm_id (prag_fn sel_name) + ; dm_id_w_inline <- addInlinePrags dm_id prags + ; spec_prags <- tcSpecPrags dm_id prags ; warnTc (not (null spec_prags)) (ptext (sLit "Ignoring SPECIALISE pragmas on default method") <+> quotes (ppr sel_name)) - ; tcInstanceMethodBody (instLoc this_dict) - tyvars [this_dict] - ([], emptyBag) + ; liftM Just $ + tcInstanceMethodBody (ClsSkol clas) + tyvars + [this_dict] + Nothing dm_id_w_inline local_dm_id dm_sig_fn IsDefaultMethod meth_bind } --------------- -tcInstanceMethodBody :: InstLoc -> [TcTyVar] -> [Inst] - -> ([Inst], LHsBinds Id) -> Id -> Id - -> TcSigFun -> TcSpecPrags -> LHsBind Name - -> TcM (Id, LHsBind Id) -tcInstanceMethodBody inst_loc tyvars dfun_dicts - (this_dict, this_bind) meth_id local_meth_id - meth_sig_fn spec_prags bind@(L loc _) +tcInstanceMethodBody :: SkolemInfo -> [TcTyVar] -> [EvVar] + -> Maybe EvBind + -> Id -> Id + -> SigFun -> TcSpecPrags -> LHsBind Name + -> TcM (LHsBind Id) +tcInstanceMethodBody skol_info tyvars dfun_ev_vars + this_dict meth_id local_meth_id + meth_sig_fn specs + (L loc bind) = do { -- Typecheck the binding, first extending the envt -- so that when tcInstSig looks up the local_meth_id to find -- its signature, we'll find it in the environment - ; ((tc_bind, _), lie) <- getLIE $ - tcExtendIdEnv [local_meth_id] $ - tcPolyBinds TopLevel meth_sig_fn no_prag_fn - NonRecursive NonRecursive - (unitBag bind) - - ; let avails = this_dict ++ dfun_dicts - -- Only need the this_dict stuff if there are type - -- variables involved; otherwise overlap is not possible - -- See Note [Subtle interaction of recursion and overlap] - -- in TcInstDcls - ; lie_binds <- tcSimplifyCheck inst_loc tyvars avails lie - - ; let full_bind = AbsBinds tyvars dfun_lam_vars - [(tyvars, meth_id, local_meth_id, spec_prags)] - (this_bind `unionBags` lie_binds - `unionBags` tc_bind) - - dfun_lam_vars = map instToVar dfun_dicts -- Includes equalities - - ; return (meth_id, L loc full_bind) } + let full_given = case this_dict of + Nothing -> dfun_ev_vars + Just (EvBind dict _) -> dict : dfun_ev_vars + lm_bind = L loc (bind { fun_id = L loc (idName local_meth_id) }) + -- Substitue the local_meth_name for the binder + -- NB: the binding is always a FunBind + + ; (ev_binds, (tc_bind, _)) + <- checkConstraints skol_info tyvars full_given $ + tcExtendIdEnv [local_meth_id] $ + tcPolyBinds TopLevel meth_sig_fn no_prag_fn + NonRecursive NonRecursive + [lm_bind] + + -- Add the binding for this_dict, if we have one + ; ev_binds' <- case this_dict of + Nothing -> return ev_binds + Just (EvBind self rhs) -> extendTcEvBinds ev_binds self rhs + + ; let full_bind = AbsBinds { abs_tvs = tyvars, abs_ev_vars = dfun_ev_vars + , abs_exports = [(tyvars, meth_id, local_meth_id, specs)] + , abs_ev_binds = ev_binds' + , abs_binds = tc_bind } + + ; return (L loc full_bind) } where no_prag_fn _ = [] -- No pragmas for local_meth_id; -- they are all for meth_id \end{code} \begin{code} -mkDefMethRdrName :: Name -> RdrName -mkDefMethRdrName sel_name = mkDerivedRdrName sel_name mkDefaultMethodOcc - instantiateMethod :: Class -> Id -> [TcType] -> TcType -- Take a class operation, say -- op :: forall ab. C a => forall c. Ix c => (b,c) -> a @@ -309,18 +301,16 @@ instantiateMethod clas sel_id inst_tys --------------------------- --- The renamer just puts the selector ID as the binder in the method binding --- but we must use the method name; so we substitute it here. Crude but simple. -findMethodBind :: Name -> Name -- Selector and method name +findMethodBind :: Name -- Selector name -> LHsBinds Name -- A group of bindings - -> Maybe (LHsBind Name) -- The binding, with meth_name replacing sel_name -findMethodBind sel_name meth_name binds + -> Maybe (LHsBind Name) -- The binding +findMethodBind sel_name binds = foldlBag mplus Nothing (mapBag f binds) where - f (L loc1 bind@(FunBind { fun_id = L loc2 op_name })) - | op_name == sel_name - = Just (L loc1 (bind { fun_id = L loc2 meth_name })) - f _other = Nothing + f bind@(L _ (FunBind { fun_id = L _ op_name })) + | op_name == sel_name + = Just bind + f _other = Nothing \end{code} Note [Polymorphic methods] @@ -380,8 +370,8 @@ gives rise to the instance declarations op Unit = ... \begin{code} -mkGenericDefMethBind :: Class -> [Type] -> Id -> Name -> TcM (LHsBind Name) -mkGenericDefMethBind clas inst_tys sel_id meth_name +mkGenericDefMethBind :: Class -> [Type] -> Id -> TcM (LHsBind Name) +mkGenericDefMethBind clas inst_tys sel_id = -- A generic default method -- If the method is defined generically, we can only do the job if the -- instance declaration is for a single-parameter type class with @@ -399,7 +389,8 @@ mkGenericDefMethBind clas inst_tys sel_id meth_name -- Rename it before returning it ; (rn_rhs, _) <- rnLExpr rhs - ; return (noLoc $ mkFunBind (noLoc meth_name) [mkSimpleMatch [] rn_rhs]) } + ; return (noLoc $ mkFunBind (noLoc (idName sel_id)) + [mkSimpleMatch [] rn_rhs]) } where rhs = mkGenericRhs sel_id clas_tyvar tycon @@ -611,7 +602,7 @@ notGeneric tycon badGenericInstanceType :: LHsBinds Name -> SDoc badGenericInstanceType binds = vcat [ptext (sLit "Illegal type pattern in the generic bindings"), - nest 4 (ppr binds)] + nest 2 (ppr binds)] missingGenericInstances :: [Name] -> SDoc missingGenericInstances missing @@ -620,7 +611,7 @@ missingGenericInstances missing dupGenericInsts :: [(TyCon, InstInfo a)] -> SDoc 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)), + nest 2 (vcat (map ppr_inst_ty tc_inst_infos)), ptext (sLit "All the type patterns for a generic type constructor must be identical") ] where