X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=compiler%2Ftypecheck%2FTcClassDcl.lhs;h=62a3da80f2e2092dc643e5d9b55c8f9ff0f876b0;hb=2a26efb65343e31957b043f63c43caf24d5eeb30;hp=8db89b9c07abffd1168f8a3aa43bfc1e390ab4ea;hpb=5cfe9e92a92201043d5dbb1c4e10fef0ed0d9f49;p=ghc-hetmet.git diff --git a/compiler/typecheck/TcClassDcl.lhs b/compiler/typecheck/TcClassDcl.lhs index 8db89b9..62a3da8 100644 --- a/compiler/typecheck/TcClassDcl.lhs +++ b/compiler/typecheck/TcClassDcl.lhs @@ -97,48 +97,36 @@ Death to "ExpandingDicts". tcClassSigs :: Name -- Name of the class -> [LSig Name] -> LHsBinds Name - -> TcM [TcMethInfo] + -> TcM [TcMethInfo] -- One for each method tcClassSigs clas sigs def_methods - = 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] - -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 -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) - - -- Check that all the defns ar generic, or none are - ; 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) + = do { -- Check that all def_methods are in the class + ; op_info <- mapM (addLocM tc_sig) [sig | sig@(L _ (TypeSig _ _)) <- sigs] + ; let op_names = [ n | (n,_,_) <- op_info ] + ; sequence [ failWithTc (badMethodErr clas n) + | n <- dm_bind_names, not (n `elem` op_names) ] + -- Value binding for non class-method (ie no TypeSig) -tcClassSig :: NameEnv DefMethSpec -- Info about default methods; - -> LSig Name - -> TcM TcMethInfo + ; sequence [ failWithTc (badGenericMethod clas n) + | n <- genop_names, not (n `elem` dm_bind_names) ] + -- Generic signature without value binding -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 = lookupNameEnv dm_env op_name `orElse` NoDM - ; return (op_name, dm, op_ty) } -tcClassSig _ s = pprPanic "tcClassSig" (ppr s) + ; return op_info } + where + dm_bind_names :: [Name] -- These ones have a value binding in the class decl + dm_bind_names = [op | L _ (FunBind {fun_id = L _ op}) <- bagToList def_methods] + + genop_names :: [Name] -- These ones have a generic signature + genop_names = [n | L _ (GenericSig (L _ n) _) <- sigs] + + tc_sig (TypeSig (L _ op_name) op_hs_ty) + = do { op_ty <- tcHsKindedType op_hs_ty -- Class tyvars already in scope + ; let dm | op_name `elem` genop_names = GenericDM + | op_name `elem` dm_bind_names = VanillaDM + | otherwise = NoDM + ; return (op_name, dm, op_ty) } + tc_sig sig = pprPanic "tc_cls_sig" (ppr sig) \end{code} @@ -174,62 +162,76 @@ tcClassDecl2 (L loc (ClassDecl {tcdLName = class_name, tcdSigs = sigs, pred = mkClassPred clas (mkTyVarTys clas_tyvars) ; this_dict <- newEvVar pred + ; traceTc "TIM2" (ppr sigs) ; let tc_dm = tcDefMeth clas clas_tyvars - this_dict default_binds + this_dict default_binds sigs sig_fn prag_fn ; dm_binds <- tcExtendTyVarEnv clas_tyvars $ mapM tc_dm op_items - ; return (listToBag (catMaybes dm_binds)) } + ; return (unionManyBags dm_binds) } tcClassDecl2 d = pprPanic "tcClassDecl2" (ppr d) -tcDefMeth :: Class -> [TyVar] -> EvVar -> LHsBinds Name +tcDefMeth :: Class -> [TyVar] -> EvVar -> LHsBinds Name -> [LSig Name] -> SigFun -> PragFun -> ClassOpItem - -> TcM (Maybe (LHsBind Id)) + -> TcM (LHsBinds TcId) -- 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 binds_in - `orElse` pprPanic "tcDefMeth" (ppr sel_id) - -- dm_info = DefMeth dm_name only if there is a binding in binds_in - - 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 <- 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)) - - ; liftM Just $ - tcInstanceMethodBody (ClsSkol clas) - tyvars - [this_dict] - dm_id_w_inline local_dm_id - dm_sig_fn IsDefaultMethod meth_bind } +tcDefMeth clas tyvars this_dict binds_in sigs sig_fn prag_fn (sel_id, dm_info) + | NoDefMeth <- dm_info = return emptyBag + | otherwise + = do { (dm_id, tvs, sig_loc) <- tc_dm_id dm_info + ; let L loc meth_bind = findMethodBind sel_name binds_in + `orElse` pprPanic "tcDefMeth" (ppr sel_id) + dm_bind = L loc (meth_bind { fun_id = L loc (idName dm_id) }) + -- Substitute the meth_name for the binder + -- NB: the binding is always a FunBind + + dm_sig_fn _ = Just (clas_tv_names ++ tvs, sig_loc) + dm_prag_fn _ = prag_fn sel_name + + ; (binds,_) <- tcExtendIdEnv [dm_id] $ + tcPolyBinds TopLevel dm_sig_fn dm_prag_fn + NonRecursive NonRecursive + [dm_bind] + ; return binds } + where + sel_name = idName sel_id + clas_tv_names = map getName tyvars + + -- Find the 'generic op :: ty' signature among the sigs + -- If dm_info is GenDefMeth, the corresponding signature + -- should jolly well exist! Hence the panic + genop_lhs_ty = case [lty | L _ (GenericSig (L _ n) lty) <- sigs + , n == sel_name ] of + [lty] -> lty + _ -> pprPanic "tcDefMeth" (ppr sel_name $$ ppr sigs) + + tc_dm_id :: DefMeth -> TcM (Id, [Name], SrcSpan) + -- Make a default-method Id of the appropriate type + -- That may entail getting the generic-default signature + -- from the type signatures. + -- Also return the in-scope tyvars for the default method, and their binding site + tc_dm_id NoDefMeth = panic "tc_dm_id" + tc_dm_id (DefMeth dm_name) + | Just (tvs, loc) <- sig_fn sel_name + = return (mkDefaultMethodId sel_id dm_name, tvs, loc) + | otherwise + = pprPanic "No sig for" (ppr sel_name) + tc_dm_id (GenDefMeth dm_name) + = setSrcSpan loc $ + do { tau <- tcHsKindedType genop_lhs_ty + ; checkValidType (FunSigCtxt sel_name) tau + ; return ( mkExportedLocalId dm_name (mkForAllTys tyvars tau) + , hsExplicitTvs genop_lhs_ty, loc ) } + where + loc = getLoc genop_lhs_ty --------------- tcInstanceMethodBody :: SkolemInfo -> [TcTyVar] -> [EvVar] @@ -246,7 +248,7 @@ tcInstanceMethodBody skol_info tyvars dfun_ev_vars let lm_bind = L loc (bind { fun_id = L loc (idName local_meth_id) }) -- Substitute the local_meth_name for the binder -- NB: the binding is always a FunBind - + ; traceTc "TIM" (ppr local_meth_id $$ ppr (meth_sig_fn (idName local_meth_id))) ; (ev_binds, (tc_bind, _)) <- checkConstraints skol_info tyvars dfun_ev_vars $ tcExtendIdEnv [local_meth_id] $ @@ -562,6 +564,11 @@ badMethodErr clas op = hsep [ptext (sLit "Class"), quotes (ppr clas), ptext (sLit "does not have a method"), quotes (ppr op)] +badGenericMethod :: Outputable a => a -> Name -> SDoc +badGenericMethod clas op + = hsep [ptext (sLit "Class"), quotes (ppr clas), + ptext (sLit "has a generic-default signature without a binding"), quotes (ppr op)] + badATErr :: Class -> Name -> SDoc badATErr clas at = hsep [ptext (sLit "Class"), quotes (ppr clas),