X-Git-Url: http://git.megacz.com/?p=ghc-hetmet.git;a=blobdiff_plain;f=compiler%2Ftypecheck%2FTcClassDcl.lhs;h=2f7f6bc3f41ae92776570c8a90cb99a97608fb7e;hp=3814f239b68f23086018dc3df42e3cf6e8b521a4;hb=786932468faac49aafe20b65eabc8bdf465fbc9d;hpb=aaed05e88978688e37dc74177dd4eba51a6ab4d0 diff --git a/compiler/typecheck/TcClassDcl.lhs b/compiler/typecheck/TcClassDcl.lhs index 3814f23..2f7f6bc 100644 --- a/compiler/typecheck/TcClassDcl.lhs +++ b/compiler/typecheck/TcClassDcl.lhs @@ -7,8 +7,8 @@ Typechecking class declarations \begin{code} module TcClassDcl ( tcClassSigs, tcClassDecl2, - findMethodBind, tcInstanceMethodBody, - mkGenericDefMethBind, getGenericInstances, mkDefMethRdrName, + findMethodBind, instantiateMethod, tcInstanceMethodBody, + mkGenericDefMethBind, getGenericInstances, tcAddDeclCtxt, badMethodErr, badATErr, omittedATWarn ) where @@ -17,7 +17,6 @@ module TcClassDcl ( tcClassSigs, tcClassDecl2, import HsSyn import RnHsSyn import RnExpr -import RnEnv import Inst import InstEnv import TcEnv @@ -27,33 +26,30 @@ import TcHsType import TcMType import TcType import TcRnMonad +import BuildTyCl( TcMethInfo ) import Generics import Class import TyCon -import Type import MkId import Id import Name import Var import NameEnv import NameSet -import OccName -import RdrName import Outputable import PrelNames import DynFlags import ErrUtils import Util -import Unique import ListSetOps import SrcLoc import Maybes -import List import BasicTypes import Bag import FastString import Control.Monad +import Data.List \end{code} @@ -102,54 +98,44 @@ 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} @@ -163,11 +149,11 @@ tcClassSig _ s = pprPanic "tcClassSig" (ppr s) \begin{code} tcClassDecl2 :: LTyClDecl Name -- The class declaration - -> TcM (LHsBinds Id, [Id]) + -> TcM ([Id], LHsBinds Id) tcClassDecl2 (L loc (ClassDecl {tcdLName = class_name, tcdSigs = sigs, tcdMeths = default_binds})) - = recoverM (return (emptyLHsBinds, [])) $ + = recoverM (return ([], emptyLHsBinds)) $ setSrcSpan loc $ do { clas <- tcLookupLocatedClass class_name @@ -182,59 +168,131 @@ tcClassDecl2 (L loc (ClassDecl {tcdLName = class_name, tcdSigs = sigs, ; let (tyvars, _, _, op_items) = classBigSig clas rigid_info = ClsSkol clas - prag_fn = mkPragFun sigs + prag_fn = mkPragFun sigs default_binds sig_fn = mkTcSigFun 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 - ; let tc_dm = tcDefMeth rigid_info clas clas_tyvars [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.) - ; (defm_binds, dm_ids) <- tcExtendTyVarEnv clas_tyvars $ - mapAndUnzipM tc_dm dm_sel_ids + ; dm_stuff <- tcExtendTyVarEnv clas_tyvars $ + mapM tc_dm op_items + ; let (dm_ids, defm_binds) = unzip (catMaybes dm_stuff) - ; return (unionManyBags defm_binds, dm_ids) } + ; return (dm_ids, listToBag defm_binds) } tcClassDecl2 d = pprPanic "tcClassDecl2" (ppr d) -tcDefMeth :: SkolemInfo -> Class -> [TyVar] -> ThetaType -> Inst -> LHsBinds Name - -> TcSigFun -> TcPragFun -> Id - -> TcM (LHsBinds Id, Id) -tcDefMeth rigid_info clas tyvars theta this_dict binds_in sig_fn prag_fn sel_id - = do { let sel_name = idName sel_id +tcDefMeth :: Class -> [TyVar] -> Inst -> LHsBinds Name + -> TcSigFun -> TcPragFun -> ClassOpItem + -> TcM (Maybe (Id, 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 `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 + local_dm_type = instantiateMethod clas sel_id (mkTyVarTys tyvars) + local_dm_id = mkLocalId local_dm_name local_dm_type + + ; (dm_id_w_inline, spec_prags) + <- tcPrags NonRecursive False True dm_id (prag_fn sel_name) + + ; warnTc (not (null spec_prags)) + (ptext (sLit "Ignoring SPECIALISE pragmas on default method") + <+> quotes (ppr sel_name)) + + ; liftM Just $ + tcInstanceMethodBody (instLoc this_dict) + tyvars [this_dict] + ([], emptyBag) + 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 _) + = 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 - meth_sig_fn _ = sig_fn sel_name - meth_prag_fn _ = prag_fn sel_name + ; return (meth_id, L loc full_bind) } + where + no_prag_fn _ = [] -- No pragmas for local_meth_id; + -- they are all for meth_id +\end{code} + +\begin{code} +instantiateMethod :: Class -> Id -> [TcType] -> TcType +-- Take a class operation, say +-- op :: forall ab. C a => forall c. Ix c => (b,c) -> a +-- Instantiate it at [ty1,ty2] +-- Return the "local method type": +-- forall c. Ix x => (ty2,c) -> ty1 +instantiateMethod clas sel_id inst_tys + = ASSERT( ok_first_pred ) local_meth_ty + where + (sel_tyvars,sel_rho) = tcSplitForAllTys (idType sel_id) + rho_ty = ASSERT( length sel_tyvars == length inst_tys ) + substTyWith sel_tyvars inst_tys sel_rho - ; (top_dm_id, bind) <- tcInstanceMethodBody rigid_info - clas tyvars [this_dict] theta (mkTyVarTys tyvars) - Nothing sel_id - local_dm_name - meth_sig_fn meth_prag_fn - meth_bind + (first_pred, local_meth_ty) = tcSplitPredFunTy_maybe rho_ty + `orElse` pprPanic "tcInstanceMethod" (ppr sel_id) - ; return (bind, top_dm_id) } + ok_first_pred = case getClassPredTys_maybe first_pred of + Just (clas1, _tys) -> clas == clas1 + Nothing -> False + -- The first predicate should be of form (C a b) + -- where C is the class in question -mkDefMethRdrName :: Name -> RdrName -mkDefMethRdrName sel_name = mkDerivedRdrName sel_name mkDefaultMethodOcc --------------------------- -- The renamer just puts the selector ID as the binder in the method binding @@ -249,65 +307,6 @@ findMethodBind sel_name meth_name binds | op_name == sel_name = Just (L loc1 (bind { fun_id = L loc2 meth_name })) f _other = Nothing - ---------------- -tcInstanceMethodBody :: SkolemInfo -> Class -> [TcTyVar] -> [Inst] - -> TcThetaType -> [TcType] - -> Maybe (Inst, LHsBind Id) -> Id - -> Name -- The local method name - -> TcSigFun -> TcPragFun -> LHsBind Name - -> TcM (Id, LHsBinds Id) -tcInstanceMethodBody rigid_info clas tyvars dfun_dicts theta inst_tys - mb_this_bind sel_id local_meth_name - sig_fn prag_fn bind@(L loc _) - = do { let (sel_tyvars,sel_rho) = tcSplitForAllTys (idType sel_id) - rho_ty = ASSERT( length sel_tyvars == length inst_tys ) - substTyWith sel_tyvars inst_tys sel_rho - - (first_pred, local_meth_ty) = tcSplitPredFunTy_maybe rho_ty - `orElse` pprPanic "tcInstanceMethod" (ppr sel_id) - - local_meth_id = mkLocalId local_meth_name local_meth_ty - meth_ty = mkSigmaTy tyvars theta local_meth_ty - sel_name = idName sel_id - - -- The first predicate should be of form (C a b) - -- where C is the class in question - ; MASSERT( case getClassPredTys_maybe first_pred of - { Just (clas1, _tys) -> clas == clas1 ; Nothing -> False } ) - - -- 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 sig_fn prag_fn - NonRecursive NonRecursive - (unitBag bind) - - ; meth_id <- case rigid_info of - ClsSkol _ -> do { dm_name <- lookupTopBndrRn (mkDefMethRdrName sel_name) - ; return (mkDefaultMethodId dm_name meth_ty) } - _other -> do { meth_name <- newLocalName sel_name - ; return (mkLocalId meth_name meth_ty) } - - ; let (avails, this_dict_bind) - = case mb_this_bind of - Nothing -> (dfun_dicts, emptyBag) - Just (this, bind) -> (this : dfun_dicts, unitBag bind) - - ; inst_loc <- getInstLoc (SigOrigin rigid_info) - ; lie_binds <- tcSimplifyCheck inst_loc tyvars avails lie - - ; let full_bind = L loc $ - AbsBinds tyvars dfun_lam_vars - [(tyvars, meth_id, local_meth_id, [])] - (this_dict_bind `unionBags` lie_binds - `unionBags` tc_bind) - - dfun_lam_vars = map instToVar dfun_dicts -- Includes equalities - - ; return (meth_id, unitBag full_bind) } \end{code} Note [Polymorphic methods] @@ -366,7 +365,6 @@ gives rise to the instance declarations instance C 1 where op Unit = ... - \begin{code} mkGenericDefMethBind :: Class -> [Type] -> Id -> Name -> TcM (LHsBind Name) mkGenericDefMethBind clas inst_tys sel_id meth_name @@ -452,7 +450,7 @@ get_generics decl@(ClassDecl {tcdLName = class_name, tcdMeths = def_methods}) group `lengthExceeds` 1] get_uniq (tc,_) = getUnique tc - mapM (addErrTc . dupGenericInsts) bad_groups + mapM_ (addErrTc . dupGenericInsts) bad_groups -- Check that there is an InstInfo for each generic type constructor let @@ -516,7 +514,8 @@ mkGenericInstance clas (hs_ty, binds) = do -- 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))) + sig_tvs = userHsTyVarBndrs $ map noLoc $ nameSetToList $ + extractHsTyVars (noLoc hs_ty) hs_forall_ty = noLoc $ mkExplicitHsForAllTy sig_tvs (noLoc []) (noLoc hs_ty) -- Type-check the instance type, and check its form @@ -536,7 +535,7 @@ mkGenericInstance clas (hs_ty, binds) = do dfun_id = mkDictFunId dfun_name tyvars inst_theta clas [inst_ty] ispec = mkLocalInstance dfun_id overlap_flag - return (InstInfo { iSpec = ispec, iBinds = VanillaInst binds [] }) + return (InstInfo { iSpec = ispec, iBinds = VanillaInst binds [] False }) \end{code}