X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=compiler%2Ftypecheck%2FTcInstDcls.lhs;h=1aa126f44f8762d239eec716389588c57d2946c6;hb=202ac08f3e2afde0620e889cc81a95b2fd0ad9e1;hp=1bb1bb76710641a8b2d05ae7c0fbcf233b460a83;hpb=44ba24dc84d271ca9bd5ab5060cb63ed87f585e3;p=ghc-hetmet.git diff --git a/compiler/typecheck/TcInstDcls.lhs b/compiler/typecheck/TcInstDcls.lhs index 1bb1bb7..1aa126f 100644 --- a/compiler/typecheck/TcInstDcls.lhs +++ b/compiler/typecheck/TcInstDcls.lhs @@ -10,13 +10,14 @@ module TcInstDcls ( tcInstDecls1, tcInstDecls2 ) where import HsSyn import TcBinds ( mkPragFun, tcPrags, badBootDeclErr ) +import TcTyClsDecls ( tcIdxTyInstDecl ) import TcClassDcl ( tcMethodBind, mkMethodBind, badMethodErr, tcClassDecl2, getGenericInstances ) import TcRnMonad import TcMType ( tcSkolSigType, checkValidInstance, checkValidInstHead ) -import TcType ( mkClassPred, tcSplitSigmaTy, tcSplitDFunHead, mkTyVarTys, +import TcType ( mkClassPred, tcSplitSigmaTy, tcSplitDFunHead, SkolemInfo(InstSkol), tcSplitDFunTy, mkFunTy ) -import Inst ( tcInstClassOp, newDicts, instToId, showLIE, +import Inst ( newDictBndr, newDictBndrs, instToId, showLIE, getOverlapFlag, tcExtendLocalInstEnv ) import InstEnv ( mkLocalInstance, instanceDFunId ) import TcDeriv ( tcDeriving ) @@ -25,19 +26,20 @@ import TcEnv ( InstInfo(..), InstBindings(..), ) import TcHsType ( kcHsSigType, tcHsKindedType ) import TcUnify ( checkSigTyVars ) -import TcSimplify ( tcSimplifyCheck, tcSimplifySuperClasses ) -import Type ( zipOpenTvSubst, substTheta, substTys, mkTyConApp, mkTyVarTy ) -import Coercion ( mkAppCoercion, mkAppsCoercion ) -import TyCon ( TyCon, newTyConCo ) +import TcSimplify ( tcSimplifySuperClasses ) +import Type ( zipOpenTvSubst, substTheta, mkTyConApp, mkTyVarTy, + splitFunTys ) +import Coercion ( mkSymCoercion ) +import TyCon ( TyCon, newTyConCo, tyConTyVars ) import DataCon ( classDataCon, dataConTyCon, dataConInstArgTys ) -import Class ( classBigSig, classMethods ) -import Var ( TyVar, Id, idName, idType ) +import Class ( classBigSig ) +import Var ( TyVar, Id, idName, idType, tyVarKind ) import Id ( mkSysLocal ) import UniqSupply ( uniqsFromSupply, splitUniqSupply ) import MkId ( mkDictFunId ) import Name ( Name, getSrcLoc ) import Maybe ( catMaybes ) -import SrcLoc ( noSrcSpan, srcLocSpan, unLoc, noLoc, Located(..), srcSpanStart ) +import SrcLoc ( srcLocSpan, unLoc, noLoc, Located(..), srcSpanStart ) import ListSetOps ( minusList ) import Outputable import Bag @@ -137,35 +139,41 @@ tcInstDecls1 -- Deal with both source-code and imported instance decls tcInstDecls1 tycl_decls inst_decls = checkNoErrs $ - -- Stop if addInstInfos etc discovers any errors - -- (they recover, so that we get more than one error each round) - - -- (1) Do the ordinary instance declarations - mappM tcLocalInstDecl1 inst_decls `thenM` \ local_inst_infos -> - - let - local_inst_info = catMaybes local_inst_infos - clas_decls = filter (isClassDecl.unLoc) tycl_decls - in - -- (2) Instances from generic class declarations - getGenericInstances clas_decls `thenM` \ generic_inst_info -> - - -- Next, construct the instance environment so far, consisting of - -- a) local instance decls - -- b) generic instances - addInsts local_inst_info $ - addInsts generic_inst_info $ - - -- (3) Compute instances from "deriving" clauses; - -- This stuff computes a context for the derived instance decl, so it - -- needs to know about all the instances possible; hence inst_env4 - tcDeriving tycl_decls `thenM` \ (deriv_inst_info, deriv_binds) -> - addInsts deriv_inst_info $ - - getGblEnv `thenM` \ gbl_env -> - returnM (gbl_env, - generic_inst_info ++ deriv_inst_info ++ local_inst_info, - deriv_binds) + do { -- Stop if addInstInfos etc discovers any errors + -- (they recover, so that we get more than one error each + -- round) + + -- (1) Do the ordinary instance declarations and instances of + -- indexed types + ; let { idxty_decls = filter (isIdxTyDecl . unLoc) tycl_decls } + ; local_inst_infos <- mappM tcLocalInstDecl1 inst_decls + ; idxty_inst_infos <- mappM tcIdxTyInstDecl idxty_decls + + ; let { local_inst_info = concat local_inst_infos ++ + catMaybes idxty_inst_infos + ; clas_decls = filter (isClassDecl.unLoc) tycl_decls } + + -- (2) Instances from generic class declarations + ; generic_inst_info <- getGenericInstances clas_decls + + -- Next, construct the instance environment so far, consisting + -- of + -- a) local instance decls + -- b) generic instances + ; addInsts local_inst_info $ do { + ; addInsts generic_inst_info $ do { + + -- (3) Compute instances from "deriving" clauses; + -- This stuff computes a context for the derived instance + -- decl, so it needs to know about all the instances possible + ; (deriv_inst_info, deriv_binds) <- tcDeriving tycl_decls + ; addInsts deriv_inst_info $ do { + + ; gbl_env <- getGblEnv + ; returnM (gbl_env, + generic_inst_info ++ deriv_inst_info ++ local_inst_info, + deriv_binds) + }}}} addInsts :: [InstInfo] -> TcM a -> TcM a addInsts infos thing_inside @@ -174,15 +182,14 @@ addInsts infos thing_inside \begin{code} tcLocalInstDecl1 :: LInstDecl Name - -> TcM (Maybe InstInfo) -- Nothing if there was an error + -> TcM [InstInfo] -- [] if there was an error -- A source-file instance declaration -- Type-check all the stuff before the "where" -- -- We check for respectable instance type, and context tcLocalInstDecl1 decl@(L loc (InstDecl poly_ty binds uprags ats)) - -- !!!TODO: Handle the `ats' parameter!!! -=chak = -- Prime error recovery, set source location - recoverM (returnM Nothing) $ + recoverM (returnM []) $ setSrcSpan loc $ addErrCtxt (instDeclCtxt1 poly_ty) $ @@ -196,15 +203,23 @@ tcLocalInstDecl1 decl@(L loc (InstDecl poly_ty binds uprags ats)) ; poly_ty' <- tcHsKindedType kinded_ty ; let (tyvars, theta, tau) = tcSplitSigmaTy poly_ty' + -- Now, check the validity of the instance. ; (clas, inst_tys) <- checkValidInstHead tau ; checkValidInstance tyvars theta clas inst_tys + -- Next, process any associated types. + ; idxty_inst_info <- mappM tcIdxTyInstDecl ats + + -- Finally, construct the Core representation of the instance. + -- (This no longer includes the associated types.) ; dfun_name <- newDFunName clas inst_tys (srcSpanStart loc) ; overlap_flag <- getOverlapFlag ; let dfun = mkDictFunId dfun_name tyvars theta clas inst_tys ispec = mkLocalInstance dfun overlap_flag - ; return (Just (InstInfo { iSpec = ispec, iBinds = VanillaInst binds uprags })) } + ; return $ [InstInfo { iSpec = ispec, + iBinds = VanillaInst binds uprags }] ++ + catMaybes idxty_inst_info } \end{code} @@ -309,7 +324,7 @@ First comes the easy case of a non-local instance decl. tcInstDecl2 :: InstInfo -> TcM (LHsBinds Id) -- Returns a binding for the dfun --- +------------------------ -- Derived newtype instances -- -- We need to make a copy of the dictionary we are deriving from @@ -320,12 +335,12 @@ tcInstDecl2 :: InstInfo -> TcM (LHsBinds Id) -- class Show a => Foo a b where ... -- newtype T a = MkT (Tree [a]) deriving( Foo Int ) -- The newtype gives an FC axiom looking like --- axiom CoT a :: Tree [a] = T a +-- axiom CoT a :: T a :=: Tree [a] -- -- So all need is to generate a binding looking like -- dfunFooT :: forall a. (Foo Int (Tree [a], Show (T a)) => Foo Int (T a) -- dfunFooT = /\a. \(ds:Show (T a)) (df:Foo (Tree [a])). --- case df `cast` (Foo Int (CoT a)) of +-- case df `cast` (Foo Int (sym (CoT a))) of -- Foo _ op1 .. opn -> Foo ds op1 .. opn tcInstDecl2 (InstInfo { iSpec = ispec, @@ -334,31 +349,35 @@ tcInstDecl2 (InstInfo { iSpec = ispec, rigid_info = InstSkol dfun_id origin = SigOrigin rigid_info inst_ty = idType dfun_id - maybe_co_con = newTyConCo tycon + ; inst_loc <- getInstLoc origin ; (tvs, theta, inst_head) <- tcSkolSigType rigid_info inst_ty - ; dicts <- newDicts origin theta + ; dicts <- newDictBndrs inst_loc theta ; uniqs <- newUniqueSupply ; let (cls, cls_inst_tys) = tcSplitDFunHead inst_head - ; [this_dict] <- newDicts origin [mkClassPred cls rep_tys] - ; let (rep_dict_id:sc_dict_ids) = - if null dicts then - [instToId this_dict] - else - map instToId dicts + ; this_dict <- newDictBndr inst_loc (mkClassPred cls rep_tys) + ; let (rep_dict_id:sc_dict_ids) + | null dicts = [instToId this_dict] + | otherwise = map instToId dicts -- (Here, we are relying on the order of dictionary -- arguments built by NewTypeDerived in TcDeriv.) - wrap_fn = CoTyLams tvs <.> CoLams (rep_dict_id:sc_dict_ids) - - coerced_rep_dict = mkHsCoerce (co_fn tvs cls_tycon) (HsVar rep_dict_id) + wrap_fn = mkCoTyLams tvs <.> mkCoLams (rep_dict_id:sc_dict_ids) + + -- we need to find the kind that this class applies to + -- and drop trailing tvs appropriately + cls_kind = tyVarKind (head (reverse (tyConTyVars cls_tycon))) + the_tvs = drop_tail (length (fst (splitFunTys cls_kind))) tvs + + coerced_rep_dict = mkHsCoerce (co_fn the_tvs cls_tycon cls_inst_tys) (HsVar rep_dict_id) body | null sc_dict_ids = coerced_rep_dict | otherwise = HsCase (noLoc coerced_rep_dict) $ MatchGroup [the_match] (mkFunTy in_dict_ty inst_head) in_dict_ty = mkTyConApp cls_tycon cls_inst_tys - the_match = mkSimpleMatch [the_pat] the_rhs + the_match = mkSimpleMatch [noLoc the_pat] the_rhs + the_rhs = mkHsConApp cls_data_con cls_inst_tys (map HsVar (sc_dict_ids ++ op_ids)) (uniqs1, uniqs2) = splitUniqSupply uniqs @@ -368,32 +387,33 @@ tcInstDecl2 (InstInfo { iSpec = ispec, dict_ids = zipWith (mkSysLocal FSLIT("dict")) (uniqsFromSupply uniqs2) (map idType sc_dict_ids) - the_pat = noLoc $ - ConPatOut { pat_con = noLoc cls_data_con, pat_tvs = [], + the_pat = ConPatOut { pat_con = noLoc cls_data_con, pat_tvs = [], pat_dicts = dict_ids, pat_binds = emptyLHsBinds, pat_args = PrefixCon (map nlVarPat op_ids), pat_ty = in_dict_ty} cls_data_con = classDataCon cls - cls_tycon = dataConTyCon cls_data_con - cls_arg_tys = dataConInstArgTys cls_data_con cls_inst_tys + cls_tycon = dataConTyCon cls_data_con + cls_arg_tys = dataConInstArgTys cls_data_con cls_inst_tys n_dict_args = if length dicts == 0 then 0 else length dicts - 1 op_tys = drop n_dict_args cls_arg_tys - the_rhs = mkHsConApp cls_data_con cls_inst_tys (map HsVar (sc_dict_ids ++ op_ids)) - dict = (mkHsCoerce wrap_fn body) - ; return (unitBag (noLoc $ VarBind (dfun_id) (noLoc dict))) } + dict = mkHsCoerce wrap_fn body + ; return (unitBag (noLoc $ VarBind dfun_id (noLoc dict))) } where - co_fn :: [TyVar] -> TyCon -> ExprCoFn - co_fn tvs cls_tycon | Just co_con <- newTyConCo tycon - = ExprCoFn (mkAppCoercion -- (mkAppsCoercion - (mkTyConApp cls_tycon []) - -- rep_tys) - (mkTyConApp co_con (map mkTyVarTy tvs))) - | otherwise - = idCoercion + -- For newtype T a = MkT + -- The returned coercion has kind :: C (T a):=:C + co_fn tvs cls_tycon cls_inst_tys | Just co_con <- newTyConCo tycon + = ExprCoFn (mkTyConApp cls_tycon (drop_tail 1 cls_inst_tys ++ + [mkSymCoercion (mkTyConApp co_con (map mkTyVarTy tvs))])) + | otherwise + = idCoercion + drop_tail n l = take (length l - n) l + +------------------------ +-- Ordinary instances tcInstDecl2 (InstInfo { iSpec = ispec, iBinds = VanillaInst monobinds uprags }) = let @@ -420,9 +440,11 @@ tcInstDecl2 (InstInfo { iSpec = ispec, iBinds = VanillaInst monobinds uprags }) origin = SigOrigin rigid_info in -- Create dictionary Ids from the specified instance contexts. - newDicts InstScOrigin sc_theta' `thenM` \ sc_dicts -> - newDicts origin dfun_theta' `thenM` \ dfun_arg_dicts -> - newDicts origin [mkClassPred clas inst_tys'] `thenM` \ [this_dict] -> + getInstLoc InstScOrigin `thenM` \ sc_loc -> + newDictBndrs sc_loc sc_theta' `thenM` \ sc_dicts -> + getInstLoc origin `thenM` \ inst_loc -> + newDictBndrs inst_loc dfun_theta' `thenM` \ dfun_arg_dicts -> + newDictBndr inst_loc (mkClassPred clas inst_tys') `thenM` \ this_dict -> -- Default-method Ids may be mentioned in synthesised RHSs, -- but they'll already be in the environment.