X-Git-Url: http://git.megacz.com/?p=ghc-hetmet.git;a=blobdiff_plain;f=compiler%2Ftypecheck%2FTcInstDcls.lhs;h=2a516618fefbacb3a01a483c53fefa5c85b99f31;hp=2db9babc797ad708f0bc33bfe868566b320bbdf6;hb=80c89b80c355b2aaebcd53330e6c6170c3f05aca;hpb=5e0ea427646a5474dd7c659b0713c6a62d8c99c7 diff --git a/compiler/typecheck/TcInstDcls.lhs b/compiler/typecheck/TcInstDcls.lhs index 2db9bab..2a51661 100644 --- a/compiler/typecheck/TcInstDcls.lhs +++ b/compiler/typecheck/TcInstDcls.lhs @@ -10,6 +10,7 @@ module TcInstDcls ( tcInstDecls1, tcInstDecls2 ) where import HsSyn import TcBinds ( mkPragFun, tcPrags, badBootDeclErr ) +import TcTyClsDecls ( tcIdxTyInstDecl ) import TcClassDcl ( tcMethodBind, mkMethodBind, badMethodErr, tcClassDecl2, getGenericInstances ) import TcRnMonad @@ -21,17 +22,18 @@ import Inst ( newDictBndr, newDictBndrs, instToId, showLIE, import InstEnv ( mkLocalInstance, instanceDFunId ) import TcDeriv ( tcDeriving ) import TcEnv ( InstInfo(..), InstBindings(..), - newDFunName, tcExtendIdEnv + newDFunName, tcExtendIdEnv, tcExtendGlobalEnv ) import TcHsType ( kcHsSigType, tcHsKindedType ) import TcUnify ( checkSigTyVars ) import TcSimplify ( tcSimplifySuperClasses ) -import Type ( zipOpenTvSubst, substTheta, mkTyConApp, mkTyVarTy ) -import Coercion ( mkAppCoercion, mkAppsCoercion, mkSymCoercion ) -import TyCon ( TyCon, newTyConCo ) +import Type ( zipOpenTvSubst, substTheta, mkTyConApp, mkTyVarTy, + splitFunTys, TyThing ) +import Coercion ( mkSymCoercion ) +import TyCon ( TyCon, newTyConCo, tyConTyVars ) import DataCon ( classDataCon, dataConTyCon, dataConInstArgTys ) import Class ( classBigSig ) -import Var ( TyVar, Id, idName, idType ) +import Var ( TyVar, Id, idName, idType, tyVarKind ) import Id ( mkSysLocal ) import UniqSupply ( uniqsFromSupply, splitUniqSupply ) import MkId ( mkDictFunId ) @@ -42,6 +44,7 @@ import ListSetOps ( minusList ) import Outputable import Bag import BasicTypes ( Activation( AlwaysActive ), InlineSpec(..) ) +import HscTypes ( implicitTyThings ) import FastString \end{code} @@ -137,35 +140,52 @@ 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_info_tycons <- mappM tcLocalInstDecl1 inst_decls + ; idxty_info_tycons <- mappM tcIdxTyInstDecl idxty_decls + + ; let { (local_infos, + local_tycons) = unzip local_info_tycons + ; (idxty_infos, + idxty_tycons) = unzip idxty_info_tycons + ; local_idxty_info = concat local_infos ++ catMaybes idxty_infos + ; local_idxty_tycon = concat local_tycons ++ + catMaybes idxty_tycons + ; clas_decls = filter (isClassDecl.unLoc) tycl_decls + ; implicit_things = concatMap implicitTyThings local_idxty_tycon + } + + -- (2) Add the tycons of associated types and their implicit + -- tythings to the global environment + ; tcExtendGlobalEnv (local_idxty_tycon ++ implicit_things) $ do { + + -- (3) 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_idxty_info $ do { + ; addInsts generic_inst_info $ do { + + -- (4) 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_idxty_info, + deriv_binds) + }}}}} addInsts :: [InstInfo] -> TcM a -> TcM a addInsts infos thing_inside @@ -174,15 +194,14 @@ addInsts infos thing_inside \begin{code} tcLocalInstDecl1 :: LInstDecl Name - -> TcM (Maybe InstInfo) -- Nothing if there was an error + -> TcM ([InstInfo], [TyThing]) -- [] 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 +215,27 @@ 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_info_tycons <- 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 })) } + ; let dfun = mkDictFunId dfun_name tyvars theta clas inst_tys + ispec = mkLocalInstance dfun overlap_flag + (idxty_infos, + idxty_tycons) = unzip idxty_info_tycons + + ; return ([InstInfo { iSpec = ispec, + iBinds = VanillaInst binds uprags }] ++ + catMaybes idxty_infos, + catMaybes idxty_tycons) + } \end{code} @@ -348,8 +379,13 @@ tcInstDecl2 (InstInfo { iSpec = ispec, -- arguments built by NewTypeDerived in TcDeriv.) wrap_fn = mkCoTyLams tvs <.> mkCoLams (rep_dict_id:sc_dict_ids) - - coerced_rep_dict = mkHsCoerce (co_fn tvs cls_tycon) (HsVar rep_dict_id) + + -- 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) $ @@ -383,14 +419,14 @@ tcInstDecl2 (InstInfo { iSpec = ispec, 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) - (mkSymCoercion (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