X-Git-Url: http://git.megacz.com/?p=ghc-hetmet.git;a=blobdiff_plain;f=compiler%2Ftypecheck%2FTcClassDcl.lhs;h=8fc8a24e7a522ecce3e255912cc634f8eacee143;hp=36bef1183db462aa07b54d87070b6724870a73b1;hb=HEAD;hpb=83f16ade9edf272c88c6b2ed8b8e951b905fe130 diff --git a/compiler/typecheck/TcClassDcl.lhs b/compiler/typecheck/TcClassDcl.lhs index 36bef11..8fc8a24 100644 --- a/compiler/typecheck/TcClassDcl.lhs +++ b/compiler/typecheck/TcClassDcl.lhs @@ -8,19 +8,15 @@ Typechecking class declarations \begin{code} module TcClassDcl ( tcClassSigs, tcClassDecl2, findMethodBind, instantiateMethod, tcInstanceMethodBody, - mkGenericDefMethBind, getGenericInstances, + mkGenericDefMethBind, tcAddDeclCtxt, badMethodErr, badATErr, omittedATWarn ) where #include "HsVersions.h" import HsSyn -import RnHsSyn -import RnExpr -import Inst -import InstEnv -import TcPat( addInlinePrags ) import TcEnv +import TcPat( addInlinePrags ) import TcBinds import TcUnify import TcHsType @@ -28,21 +24,15 @@ import TcMType import TcType import TcRnMonad import BuildTyCl( TcMethInfo ) -import Generics import Class -import TyCon -import MkId import Id import Name -import Var import NameEnv import NameSet +import Var import Outputable -import PrelNames import DynFlags import ErrUtils -import Util -import ListSetOps import SrcLoc import Maybes import BasicTypes @@ -50,7 +40,6 @@ import Bag import FastString import Control.Monad -import Data.List \end{code} @@ -94,39 +83,43 @@ Death to "ExpandingDicts". %************************************************************************ \begin{code} -tcClassSigs :: Name -- Name of the class +tcClassSigs :: Name -- Name of the class -> [LSig Name] -> LHsBinds Name - -> TcM [TcMethInfo] -- One for each method - + -> TcM ([TcMethInfo], -- Exactly one for each method + NameEnv Type) -- Types of the generic-default methods tcClassSigs clas sigs def_methods - = 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 ] + = do { gen_dm_prs <- mapM (addLocM tc_gen_sig) gen_sigs + ; let gen_dm_env = mkNameEnv gen_dm_prs + + ; op_info <- mapM (addLocM (tc_sig gen_dm_env)) vanilla_sigs - ; sequence [ failWithTc (badMethodErr clas n) - | n <- dm_bind_names, not (n `elem` op_names) ] - -- Value binding for non class-method (ie no TypeSig) + ; let op_names = mkNameSet [ n | (n,_,_) <- op_info ] + ; sequence_ [ failWithTc (badMethodErr clas n) + | n <- dm_bind_names, not (n `elemNameSet` op_names) ] + -- Value binding for non class-method (ie no TypeSig) - ; sequence [ failWithTc (badGenericMethod clas n) - | n <- genop_names, not (n `elem` dm_bind_names) ] - -- Generic signature without value binding + ; sequence_ [ failWithTc (badGenericMethod clas n) + | (n,_) <- gen_dm_prs, not (n `elem` dm_bind_names) ] + -- Generic signature without value binding - ; return op_info } + ; return (op_info, gen_dm_env) } where + vanilla_sigs = [L loc (nm,ty) | L loc (TypeSig nm ty) <- sigs] + gen_sigs = [L loc (nm,ty) | L loc (GenericSig nm ty) <- sigs] 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) + tc_sig genop_env (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 + ; let dm | op_name `elemNameEnv` genop_env = 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) + + tc_gen_sig (L _ op_name, gen_hs_ty) + = do { gen_op_ty <- tcHsKindedType gen_hs_ty + ; return (op_name, gen_op_ty) } \end{code} @@ -164,7 +157,7 @@ tcClassDecl2 (L loc (ClassDecl {tcdLName = class_name, tcdSigs = sigs, ; traceTc "TIM2" (ppr sigs) ; let tc_dm = tcDefMeth clas clas_tyvars - this_dict default_binds sigs + this_dict default_binds sig_fn prag_fn ; dm_binds <- tcExtendTyVarEnv clas_tyvars $ @@ -174,7 +167,7 @@ tcClassDecl2 (L loc (ClassDecl {tcdLName = class_name, tcdSigs = sigs, tcClassDecl2 d = pprPanic "tcClassDecl2" (ppr d) -tcDefMeth :: Class -> [TyVar] -> EvVar -> LHsBinds Name -> [LSig Name] +tcDefMeth :: Class -> [TyVar] -> EvVar -> LHsBinds Name -> SigFun -> PragFun -> ClassOpItem -> TcM (LHsBinds TcId) -- Generate code for polymorphic default methods only (hence DefMeth) @@ -183,55 +176,47 @@ tcDefMeth :: Class -> [TyVar] -> EvVar -> LHsBinds Name -> [LSig Name] -- 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 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 } +tcDefMeth clas tyvars this_dict binds_in sig_fn prag_fn (sel_id, dm_info) + = case dm_info of + NoDefMeth -> do { mapM_ (addLocM (badDmPrag sel_id)) prags + ; return emptyBag } + DefMeth dm_name -> tc_dm dm_name + GenDefMeth dm_name -> tc_dm dm_name 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 + prags = prag_fn sel_name + dm_sig_fn _ = sig_fn sel_name + dm_bind = findMethodBind sel_name binds_in + `orElse` pprPanic "tcDefMeth" (ppr sel_id) + + -- Eg. class C a where + -- op :: forall b. Eq b => a -> [b] -> a + -- gen_op :: a -> a + -- generic gen_op :: D a => a -> a + -- The "local_dm_ty" is precisely the type in the above + -- type signatures, ie with no "forall a. C a =>" prefix + + tc_dm dm_name + = do { dm_id <- tcLookupId dm_name + ; local_dm_name <- newLocalName sel_name + -- Base the local_dm_name on the selector name, because + -- type errors from tcInstanceMethodBody come from here + + ; let local_dm_ty = instantiateMethod clas dm_id (mkTyVarTys tyvars) + local_dm_id = mkLocalId local_dm_name local_dm_ty + + ; 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)) + + ; tc_bind <- tcInstanceMethodBody (ClsSkol clas) tyvars [this_dict] + dm_id_w_inline local_dm_id dm_sig_fn + IsDefaultMethod dm_bind + + ; return (unitBag tc_bind) } --------------- tcInstanceMethodBody :: SkolemInfo -> [TcTyVar] -> [EvVar] @@ -375,143 +360,8 @@ mkGenericDefMethBind clas inst_tys sel_id dm_name [mkSimpleMatch [] rhs]) } where rhs = nlHsVar dm_name - ---------------------------- -getGenericInstances :: [LTyClDecl Name] -> TcM [InstInfo Name] -getGenericInstances 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 return [] - else do - - -- Otherwise print it out - { dumpDerivingInfo $ hang (ptext (sLit "Generic instances")) - 2 (vcat (map pprInstInfoDetails gen_inst_info)) - ; return gen_inst_info }} - -get_generics :: TyClDecl Name -> TcM [InstInfo Name] -get_generics decl@(ClassDecl {tcdLName = class_name, tcdMeths = def_methods}) - | null generic_binds - = return [] -- The comon case: no generic default methods - - | otherwise -- A source class decl with generic default methods - = 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 - - 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 - -- f {| a+b |} ... = ... - -- f {| x+y |} ... = ... - -- Then at this point we'll have an InstInfo for each - -- - -- The class should be unary, which is why simpleInstInfoTyCon should be ok - let - tc_inst_infos :: [(TyCon, InstInfo Name)] - tc_inst_infos = [(simpleInstInfoTyCon i, i) | i <- inst_infos] - - bad_groups = [group | group <- equivClassesByUniq get_uniq tc_inst_infos, - group `lengthExceeds` 1] - get_uniq (tc,_) = getUnique tc - - 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] - - checkTc (null missing) (missingGenericInstances missing) - - return inst_infos - where - generic_binds :: [(HsType Name, LHsBind Name)] - generic_binds = getGenericBinds def_methods -get_generics decl = pprPanic "get_generics" (ppr decl) - - ---------------------------------- -getGenericBinds :: LHsBinds Name -> [(HsType Name, LHsBind Name)] - -- 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 binds = concat (map getGenericBind (bagToList binds)) - -getGenericBind :: LHsBindLR Name Name -> [(HsType Name, LHsBindLR Name Name)] -getGenericBind (L loc bind@(FunBind { fun_matches = MatchGroup matches ty })) - = groupWith wrap (mapCatMaybes maybeGenericMatch matches) - where - wrap ms = L loc (bind { fun_matches = MatchGroup ms ty }) -getGenericBind _ - = [] - -groupWith :: ([a] -> b) -> [(HsType Name, a)] -> [(HsType Name, b)] -groupWith _ [] = [] -groupWith op ((t,v):prs) = (t, op (v:vs)) : groupWith op rest - where - vs = map snd this - (this,rest) = partition same_t prs - same_t (t', _v) = t `eqPatType` t' - -eqPatLType :: LHsType Name -> LHsType Name -> Bool -eqPatLType t1 t2 = unLoc t1 `eqPatType` unLoc t2 - -eqPatType :: HsType Name -> HsType Name -> Bool --- A very simple equality function, only for --- type patterns in generic function definitions. -eqPatType (HsTyVar v1) (HsTyVar v2) = v1==v2 -eqPatType (HsAppTy s1 t1) (HsAppTy s2 t2) = s1 `eqPatLType` s2 && t1 `eqPatLType` t2 -eqPatType (HsOpTy s1 op1 t1) (HsOpTy s2 op2 t2) = s1 `eqPatLType` s2 && t1 `eqPatLType` t2 && unLoc op1 == unLoc op2 -eqPatType (HsNumTy n1) (HsNumTy n2) = n1 == n2 -eqPatType (HsParTy t1) t2 = unLoc t1 `eqPatType` t2 -eqPatType t1 (HsParTy t2) = t1 `eqPatType` unLoc t2 -eqPatType _ _ = False - ---------------------------------- -mkGenericInstance :: Class - -> (HsType Name, LHsBinds Name) - -> TcM (InstInfo Name) - -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 - -- and wrap them as forall'd tyvars, so that kind inference - -- works in the standard way - let - 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 - forall_inst_ty <- tcHsSigType GenPatCtxt hs_forall_ty - let - (tyvars, inst_ty) = tcSplitForAllTys forall_inst_ty - - checkTc (validGenericInstanceType inst_ty) - (badGenericInstanceType binds) - - -- Make the dictionary function. - 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 - - return (InstInfo { iSpec = ispec, iBinds = VanillaInst binds [] False }) \end{code} - %************************************************************************ %* * Error messages @@ -555,23 +405,7 @@ badATErr clas at omittedATWarn :: Name -> SDoc omittedATWarn at = ptext (sLit "No explicit AT declaration for") <+> quotes (ppr at) - -badGenericInstance :: Var -> SDoc -> SDoc -badGenericInstance sel_id because - = sep [ptext (sLit "Can't derive generic code for") <+> quotes (ppr sel_id), - because] - -notSimple :: [Type] -> SDoc -notSimple inst_tys - = vcat [ptext (sLit "because the instance type(s)"), - nest 2 (ppr inst_tys), - ptext (sLit "is not a simple type of form (T a1 ... an)")] - -notGeneric :: TyCon -> SDoc -notGeneric tycon - = vcat [ptext (sLit "because the instance type constructor") <+> quotes (ppr tycon) <+> - ptext (sLit "was not compiled with -XGenerics")] - +{- badGenericInstanceType :: LHsBinds Name -> SDoc badGenericInstanceType binds = vcat [ptext (sLit "Illegal type pattern in the generic bindings"), @@ -589,8 +423,10 @@ dupGenericInsts tc_inst_infos ] where ppr_inst_ty (_,inst) = ppr (simpleInstInfoTy inst) - -mixedGenericErr :: Name -> SDoc -mixedGenericErr op - = ptext (sLit "Can't mix generic and non-generic equations for class method") <+> quotes (ppr op) +-} +badDmPrag :: Id -> Sig Name -> TcM () +badDmPrag sel_id prag + = addErrTc (ptext (sLit "The") <+> hsSigDoc prag <+> ptext (sLit "for default method") + <+> quotes (ppr sel_id) + <+> ptext (sLit "lacks an accompanying binding")) \end{code}