X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=compiler%2Ftypecheck%2FTcClassDcl.lhs;h=fe7cb81639f09c12b18b0073a84a9280d8b7c459;hb=74e1e73af872e63fbbec2bc9442494c3657053c3;hp=a5ce2eaf62f48841f2d19bda10953dccb61c6214;hpb=ce2ea8274f72199ac32d5219fcadb0aaeb968707;p=ghc-hetmet.git diff --git a/compiler/typecheck/TcClassDcl.lhs b/compiler/typecheck/TcClassDcl.lhs index a5ce2ea..fe7cb81 100644 --- a/compiler/typecheck/TcClassDcl.lhs +++ b/compiler/typecheck/TcClassDcl.lhs @@ -8,17 +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 Inst -import InstEnv import TcEnv +import TcPat( addInlinePrags ) import TcBinds import TcUnify import TcHsType @@ -26,20 +24,13 @@ import TcMType import TcType import TcRnMonad import BuildTyCl( TcMethInfo ) -import Generics import Class -import TyCon -import MkId import Id import Name import Var -import NameSet import Outputable -import PrelNames import DynFlags import ErrUtils -import Util -import ListSetOps import SrcLoc import Maybes import BasicTypes @@ -47,7 +38,6 @@ import Bag import FastString import Control.Monad -import Data.List \end{code} @@ -180,55 +170,67 @@ 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 _ tyvars _ 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 sigs 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 (instantiateMethod clas sel_id (mkTyVarTys tyvars)) + GenDefMeth dm_name -> do { tau <- tc_genop_ty (findGenericSig sigs sel_name) + ; tc_dm dm_name tau } + -- In the case of a generic default, we have to get the type from the signature + -- Otherwise we can get it by instantiating the method selector 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 local_dm_ty + = do { local_dm_name <- newLocalName sel_name + -- Base the local_dm_name on the selector name, because + -- type errors from tcInstanceMethodBody come from here + + ; let dm_ty = mkSigmaTy tyvars [mkClassPred clas (mkTyVarTys tyvars)] local_dm_ty + dm_id = mkExportedLocalId dm_name dm_ty + 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) } + + tc_genop_ty :: LHsType Name -> TcM Type + tc_genop_ty hs_ty + = setSrcSpan (getLoc hs_ty) $ + do { tau <- tcHsKindedType hs_ty + ; checkValidType (FunSigCtxt sel_name) tau + ; return tau } + +findGenericSig :: [LSig Name] -> Name -> LHsType Name +-- Find the 'generic op :: ty' signature among the sigs +-- If dm_info is GenDefMeth, the corresponding signature +-- should jolly well exist! Hence the panic +findGenericSig sigs sel_name + = case [lty | L _ (GenericSig (L _ n) lty) <- sigs + , n == sel_name ] of + [lty] -> lty + _ -> pprPanic "tcDefMeth" (ppr sel_name $$ ppr sigs) --------------- tcInstanceMethodBody :: SkolemInfo -> [TcTyVar] -> [EvVar] @@ -372,143 +374,8 @@ 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 @@ -552,7 +419,7 @@ badATErr clas at omittedATWarn :: Name -> SDoc omittedATWarn at = ptext (sLit "No explicit AT declaration for") <+> quotes (ppr at) - +{- badGenericInstanceType :: LHsBinds Name -> SDoc badGenericInstanceType binds = vcat [ptext (sLit "Illegal type pattern in the generic bindings"), @@ -570,4 +437,10 @@ dupGenericInsts tc_inst_infos ] where ppr_inst_ty (_,inst) = ppr (simpleInstInfoTy inst) +-} +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}