From 57e2a6906e520cd988e8c6010c52f720efe8b985 Mon Sep 17 00:00:00 2001 From: Twan van Laarhoven Date: Thu, 17 Jan 2008 21:14:39 +0000 Subject: [PATCH] Monadify typecheck/TcClassDcl: use do, return and standard monad functions --- compiler/typecheck/TcClassDcl.lhs | 172 ++++++++++++++++++------------------- 1 file changed, 85 insertions(+), 87 deletions(-) diff --git a/compiler/typecheck/TcClassDcl.lhs b/compiler/typecheck/TcClassDcl.lhs index 2e7603b..daa03d0 100644 --- a/compiler/typecheck/TcClassDcl.lhs +++ b/compiler/typecheck/TcClassDcl.lhs @@ -114,7 +114,7 @@ type TcMethInfo = (Name, DefMeth, Type) -- A temporary intermediate, to communic -- between tcClassSigs and buildClass tcClassSigs clas sigs def_methods = do { dm_env <- checkDefaultBinds clas op_names def_methods - ; mappM (tcClassSig dm_env) op_sigs } + ; mapM (tcClassSig dm_env) op_sigs } where op_sigs = [sig | sig@(L _ (TypeSig _ _)) <- sigs] op_names = [n | sig@(L _ (TypeSig (L _ n) _)) <- op_sigs] @@ -137,7 +137,7 @@ checkDefaultBind clas ops (FunBind {fun_id = L _ op, fun_matches = MatchGroup ma -- Check that all the defns ar generic, or none are ; checkTc (all_generic || none_generic) (mixedGenericErr op) - ; returnM (op, all_generic) + ; return (op, all_generic) } where n_generic = count (isJust . maybeGenericMatch) matches @@ -156,7 +156,7 @@ tcClassSig dm_env (L loc (TypeSig (L _ op_name) op_hs_ty)) Nothing -> NoDefMeth Just False -> DefMeth Just True -> GenDefMeth - ; returnM (op_name, dm, op_ty) } + ; return (op_name, dm, op_ty) } \end{code} @@ -230,9 +230,9 @@ tcClassDecl2 :: LTyClDecl Name -- The class declaration tcClassDecl2 (L loc (ClassDecl {tcdLName = class_name, tcdSigs = sigs, tcdMeths = default_binds})) - = recoverM (returnM (emptyLHsBinds, [])) $ - setSrcSpan loc $ - tcLookupLocatedClass class_name `thenM` \ clas -> + = recoverM (return (emptyLHsBinds, [])) $ + setSrcSpan loc $ do + clas <- tcLookupLocatedClass class_name -- We make a separate binding for each default method. -- At one time I used a single AbsBinds for all of them, thus @@ -259,9 +259,9 @@ tcClassDecl2 (L loc (ClassDecl {tcdLName = class_name, tcdSigs = sigs, -- 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.) - in - mapAndUnzipM tc_dm dm_sel_ids `thenM` \ (defm_binds, dm_ids_s) -> - returnM (listToBag defm_binds, concat dm_ids_s) + + (defm_binds, dm_ids_s) <- mapAndUnzipM tc_dm dm_sel_ids + return (listToBag defm_binds, concat dm_ids_s) tcDefMeth origin clas tyvars binds_in sig_fn prag_fn sel_id = do { dm_name <- lookupTopBndrRn (mkDefMethRdrName sel_id) @@ -301,7 +301,7 @@ tcDefMeth origin clas tyvars binds_in sig_fn prag_fn sel_id [instToId this_dict] [(tyvars, local_dm_id, dm_inst_id, prags)] (dict_binds `unionBags` defm_bind) - ; returnM (noLoc full_bind, [local_dm_id]) }} + ; return (noLoc full_bind, [local_dm_id]) }} mkDefMethRdrName :: Id -> RdrName mkDefMethRdrName sel_id = mkDerivedRdrName (idName sel_id) mkDefaultMethodOcc @@ -341,7 +341,7 @@ tcMethodBind tcMethodBind inst_tyvars inst_theta avail_insts sig_fn prag_fn (sel_id, meth_id, meth_bind) - = recoverM (returnM emptyLHsBinds) $ + = recoverM (return emptyLHsBinds) $ do -- If anything fails, recover returning no bindings. -- This is particularly useful when checking the default-method binding of -- a class decl. If we don't recover, we don't add the default method to @@ -353,13 +353,13 @@ tcMethodBind inst_tyvars inst_theta avail_insts sig_fn prag_fn let sel_name = idName sel_id meth_sig_fn meth_name = ASSERT( meth_name == idName meth_id ) sig_fn sel_name -- The meth_bind metions the meth_name, but sig_fn is indexed by sel_name - in - tcExtendTyVarEnv inst_tyvars ( - tcExtendIdEnv [meth_id] $ -- In scope for tcInstSig - addErrCtxt (methodCtxt sel_id) $ - getLIE $ - tcMonoBinds [meth_bind] meth_sig_fn Recursive - ) `thenM` \ ((meth_bind, mono_bind_infos), meth_lie) -> + + ((meth_bind, mono_bind_infos), meth_lie) + <- tcExtendTyVarEnv inst_tyvars $ + tcExtendIdEnv [meth_id] $ -- In scope for tcInstSig + addErrCtxt (methodCtxt sel_id) $ + getLIE $ + tcMonoBinds [meth_bind] meth_sig_fn Recursive -- Now do context reduction. We simplify wrt both the local tyvars -- and the ones of the class/instance decl, so that there is @@ -372,28 +372,26 @@ tcMethodBind inst_tyvars inst_theta avail_insts sig_fn prag_fn let [(_, Just sig, local_meth_id)] = mono_bind_infos loc = sig_loc sig - in - addErrCtxtM (sigCtxt sel_id inst_tyvars inst_theta (idType meth_id)) $ - newDictBndrs loc (sig_theta sig) `thenM` \ meth_dicts -> - let + addErrCtxtM (sigCtxt sel_id inst_tyvars inst_theta (idType meth_id)) $ do + meth_dicts <- newDictBndrs loc (sig_theta sig) + let meth_tvs = sig_tvs sig all_tyvars = meth_tvs ++ inst_tyvars all_insts = avail_insts ++ meth_dicts - in - tcSimplifyCheck - loc all_tyvars all_insts meth_lie `thenM` \ lie_binds -> - checkSigTyVars all_tyvars `thenM_` + lie_binds <- tcSimplifyCheck loc all_tyvars all_insts meth_lie - tcPrags meth_id (prag_fn sel_name) `thenM` \ prags -> - let + checkSigTyVars all_tyvars + + prags <- tcPrags meth_id (prag_fn sel_name) + let poly_meth_bind = noLoc $ AbsBinds meth_tvs (map instToId meth_dicts) [(meth_tvs, meth_id, local_meth_id, prags)] (lie_binds `unionBags` meth_bind) - in - returnM (unitBag poly_meth_bind) + + return (unitBag poly_meth_bind) mkMethodBind :: InstOrigin @@ -405,23 +403,23 @@ mkMethodBind :: InstOrigin -- Find the binding for the specified method, or make -- up a suitable default method if it isn't there -mkMethodBind origin clas inst_tys meth_binds (sel_id, dm_info) - = mkMethId origin clas sel_id inst_tys `thenM` \ (mb_inst, meth_id) -> +mkMethodBind origin clas inst_tys meth_binds (sel_id, dm_info) = do + (mb_inst, meth_id) <- mkMethId origin clas sel_id inst_tys let meth_name = idName meth_id - in + -- Figure out what method binding to use -- If the user suppplied one, use it, else construct a default one - getSrcSpanM `thenM` \ loc -> - (case find_bind (idName sel_id) meth_name meth_binds of - Just user_bind -> returnM user_bind - Nothing -> - mkDefMethRhs origin clas inst_tys sel_id loc dm_info `thenM` \ rhs -> - -- Not infix decl - returnM (noLoc $ mkFunBind (noLoc meth_name) [mkSimpleMatch [] rhs]) - ) `thenM` \ meth_bind -> + loc <- getSrcSpanM + meth_bind + <- case find_bind (idName sel_id) meth_name meth_binds of + Just user_bind -> return user_bind + Nothing -> do + rhs <- mkDefMethRhs origin clas inst_tys sel_id loc dm_info + -- Not infix decl + return (noLoc $ mkFunBind (noLoc meth_name) [mkSimpleMatch [] rhs]) - returnM (mb_inst, (sel_id, meth_id, meth_bind)) + return (mb_inst, (sel_id, meth_id, meth_bind)) mkMethId :: InstOrigin -> Class -> Id -> [TcType] -- Selector, and instance types @@ -442,12 +440,12 @@ mkMethId origin clas sel_id inst_tys case getClassPredTys_maybe first_pred of { Just (clas1,tys) -> clas == clas1 ; Nothing -> False } ) - if isSingleton preds then + if isSingleton preds then do -- If it's the only one, make a 'method' - getInstLoc origin `thenM` \ inst_loc -> - newMethod inst_loc sel_id inst_tys `thenM` \ meth_inst -> - returnM (Just meth_inst, instToId meth_inst) - else + inst_loc <- getInstLoc origin + meth_inst <- newMethod inst_loc sel_id inst_tys + return (Just meth_inst, instToId meth_inst) + else do -- If it's not the only one we need to be careful -- For example, given 'op' defined thus: -- class Foo a where @@ -457,33 +455,33 @@ mkMethId origin clas sel_id inst_tys -- That is, the class-op's context is still there. -- BUT: it can't be a Method any more, because it breaks -- INVARIANT 2 of methods. (See the data decl for Inst.) - newUnique `thenM` \ uniq -> - getSrcSpanM `thenM` \ loc -> + uniq <- newUnique + loc <- getSrcSpanM let real_tau = mkPhiTy (tail preds) tau meth_id = mkUserLocal (getOccName sel_id) uniq real_tau loc - in - returnM (Nothing, meth_id) + + return (Nothing, meth_id) -- The user didn't supply a method binding, -- so we have to make up a default binding -- The RHS of a default method depends on the default-method info -mkDefMethRhs origin clas inst_tys sel_id loc DefMeth - = -- An polymorphic default method - lookupImportedName (mkDefMethRdrName sel_id) `thenM` \ dm_name -> +mkDefMethRhs origin clas inst_tys sel_id loc DefMeth = do + -- An polymorphic default method + dm_name <- lookupImportedName (mkDefMethRdrName sel_id) -- Might not be imported, but will be an OrigName - traceRn (text "mkDefMeth" <+> ppr dm_name) `thenM_` - returnM (nlHsVar dm_name) + traceRn (text "mkDefMeth" <+> ppr dm_name) + return (nlHsVar dm_name) -mkDefMethRhs origin clas inst_tys sel_id loc NoDefMeth - = -- No default method +mkDefMethRhs origin clas inst_tys sel_id loc NoDefMeth = do + -- No default method -- Warn only if -fwarn-missing-methods - doptM Opt_WarnMissingMethods `thenM` \ warn -> + warn <- doptM Opt_WarnMissingMethods warnTc (isInstDecl origin && warn && reportIfUnused (getOccName sel_id)) - (omittedMethodWarn sel_id) `thenM_` - returnM error_rhs + (omittedMethodWarn sel_id) + return error_rhs where error_rhs = noLoc $ HsLam (mkMatchGroup [mkSimpleMatch wild_pats simple_rhs]) simple_rhs = nlHsApp (nlHsVar (getName nO_METHOD_BINDING_ERROR_ID)) @@ -529,7 +527,7 @@ mkDefMethRhs origin clas inst_tys sel_id loc GenDefMeth -- Rename it before returning it ; (rn_rhs, _) <- rnLExpr rhs - ; returnM rn_rhs } + ; return rn_rhs } where rhs = mkGenericRhs sel_id clas_tyvar tycon @@ -595,34 +593,34 @@ gives rise to the instance declarations \begin{code} getGenericInstances :: [LTyClDecl Name] -> TcM [InstInfo] getGenericInstances class_decls - = do { gen_inst_infos <- mappM (addLocM get_generics) class_decls + = do { gen_inst_infos <- mapM (addLocM get_generics) class_decls ; let { gen_inst_info = concat gen_inst_infos } -- Return right away if there is no generic stuff - ; if null gen_inst_info then returnM [] + ; if null gen_inst_info then return [] else do -- Otherwise print it out { dflags <- getDOpts ; ioToTcRn (dumpIfSet_dyn dflags Opt_D_dump_deriv "Generic instances" (vcat (map pprInstInfoDetails gen_inst_info))) - ; returnM gen_inst_info }} + ; return gen_inst_info }} get_generics decl@(ClassDecl {tcdLName = class_name, tcdMeths = def_methods}) | null generic_binds - = returnM [] -- The comon case: no generic default methods + = return [] -- The comon case: no generic default methods | otherwise -- A source class decl with generic default methods - = recoverM (returnM []) $ - tcAddDeclCtxt decl $ - tcLookupLocatedClass class_name `thenM` \ clas -> + = recoverM (return []) $ + tcAddDeclCtxt decl $ do + clas <- tcLookupLocatedClass class_name -- Group by type, and -- make an InstInfo out of each group let groups = groupWith listToBag generic_binds - in - mappM (mkGenericInstance clas) groups `thenM` \ inst_infos -> + + inst_infos <- mapM (mkGenericInstance clas) groups -- Check that there is only one InstInfo for each type constructor -- The main way this can fail is if you write @@ -638,16 +636,16 @@ get_generics decl@(ClassDecl {tcdLName = class_name, tcdMeths = def_methods}) bad_groups = [group | group <- equivClassesByUniq get_uniq tc_inst_infos, group `lengthExceeds` 1] get_uniq (tc,_) = getUnique tc - in - mappM (addErrTc . dupGenericInsts) bad_groups `thenM_` + + mapM (addErrTc . dupGenericInsts) bad_groups -- Check that there is an InstInfo for each generic type constructor let missing = genericTyConNames `minusList` [tyConName tc | (tc,_) <- tc_inst_infos] - in - checkTc (null missing) (missingGenericInstances missing) `thenM_` - returnM inst_infos + checkTc (null missing) (missingGenericInstances missing) + + return inst_infos where generic_binds :: [(HsType Name, LHsBind Name)] generic_binds = getGenericBinds def_methods @@ -693,35 +691,35 @@ mkGenericInstance :: Class -> (HsType Name, LHsBinds Name) -> TcM InstInfo -mkGenericInstance clas (hs_ty, binds) +mkGenericInstance clas (hs_ty, binds) = do -- Make a generic instance declaration -- For example: instance (C a, C b) => C (a+b) where { binds } - = -- Extract the universally quantified type variables + -- Extract the universally quantified type variables -- and wrap them as forall'd tyvars, so that kind inference -- works in the standard way let sig_tvs = map (noLoc.UserTyVar) (nameSetToList (extractHsTyVars (noLoc hs_ty))) hs_forall_ty = noLoc $ mkExplicitHsForAllTy sig_tvs (noLoc []) (noLoc hs_ty) - in + -- Type-check the instance type, and check its form - tcHsSigType GenPatCtxt hs_forall_ty `thenM` \ forall_inst_ty -> + forall_inst_ty <- tcHsSigType GenPatCtxt hs_forall_ty let (tyvars, inst_ty) = tcSplitForAllTys forall_inst_ty - in + checkTc (validGenericInstanceType inst_ty) - (badGenericInstanceType binds) `thenM_` + (badGenericInstanceType binds) -- Make the dictionary function. - getSrcSpanM `thenM` \ span -> - getOverlapFlag `thenM` \ overlap_flag -> - newDFunName clas [inst_ty] span `thenM` \ dfun_name -> + span <- getSrcSpanM + overlap_flag <- getOverlapFlag + dfun_name <- newDFunName clas [inst_ty] span let inst_theta = [mkClassPred clas [mkTyVarTy tv] | tv <- tyvars] dfun_id = mkDictFunId dfun_name tyvars inst_theta clas [inst_ty] ispec = mkLocalInstance dfun_id overlap_flag - in - returnM (InstInfo { iSpec = ispec, iBinds = VanillaInst binds [] }) + + return (InstInfo { iSpec = ispec, iBinds = VanillaInst binds [] }) \end{code} -- 1.7.10.4