{- (c) The University of Glasgow 2006 (c) The AQUA Project, Glasgow University, 1996-1998 TcHsSyn: Specialisations of the @HsSyn@ syntax for the typechecker This module is an extension of @HsSyn@ syntax, for use in the type checker. -} {-# LANGUAGE CPP #-} module TcHsSyn ( mkHsConApp, mkHsDictLet, mkHsApp, hsLitType, hsLPatType, hsPatType, mkHsAppTy, mkSimpleHsAlt, nlHsIntLit, shortCutLit, hsOverLitName, conLikeResTy, -- re-exported from TcMonad TcId, TcIdSet, zonkTopDecls, zonkTopExpr, zonkTopLExpr, zonkTopBndrs, zonkTyBndrsX, emptyZonkEnv, mkEmptyZonkEnv, mkTyVarZonkEnv, zonkTcTypeToType, zonkTcTypeToTypes, zonkTyVarOcc, ) where #include "HsVersions.h" import HsSyn import Id import TcRnMonad import PrelNames import TypeRep -- We can see the representation of types import TcType import RdrName ( RdrName, rdrNameOcc ) import TcMType ( defaultKindVarToStar, zonkQuantifiedTyVar, writeMetaTyVar ) import TcEvidence import Coercion import TysPrim import TysWiredIn import Type import ConLike import DataCon import Name import NameSet import Var import VarSet import VarEnv import DynFlags import Literal import BasicTypes import Maybes import SrcLoc import Bag import FastString import Outputable import Util #if __GLASGOW_HASKELL__ < 709 import Data.Traversable ( traverse ) #endif {- ************************************************************************ * * \subsection[mkFailurePair]{Code for pattern-matching and other failures} * * ************************************************************************ Note: If @hsLPatType@ doesn't bear a strong resemblance to @exprType@, then something is wrong. -} hsLPatType :: OutPat Id -> Type hsLPatType (L _ pat) = hsPatType pat hsPatType :: Pat Id -> Type hsPatType (ParPat pat) = hsLPatType pat hsPatType (WildPat ty) = ty hsPatType (VarPat (L _ var)) = idType var hsPatType (BangPat pat) = hsLPatType pat hsPatType (LazyPat pat) = hsLPatType pat hsPatType (LitPat lit) = hsLitType lit hsPatType (AsPat var _) = idType (unLoc var) hsPatType (ViewPat _ _ ty) = ty hsPatType (ListPat _ ty Nothing) = mkListTy ty hsPatType (ListPat _ _ (Just (ty,_))) = ty hsPatType (PArrPat _ ty) = mkPArrTy ty hsPatType (TuplePat _ bx tys) = mkTupleTy bx tys hsPatType (ConPatOut { pat_con = L _ con, pat_arg_tys = tys }) = conLikeResTy con tys hsPatType (SigPatOut _ ty) = ty hsPatType (NPat (L _ lit) _ _) = overLitType lit hsPatType (NPlusKPat id _ _ _) = idType (unLoc id) hsPatType (CoPat _ _ ty) = ty hsPatType p = pprPanic "hsPatType" (ppr p) hsLitType :: HsLit -> TcType hsLitType (HsChar _ _) = charTy hsLitType (HsCharPrim _ _) = charPrimTy hsLitType (HsString _ _) = stringTy hsLitType (HsStringPrim _ _) = addrPrimTy hsLitType (HsInt _ _) = intTy hsLitType (HsIntPrim _ _) = intPrimTy hsLitType (HsWordPrim _ _) = wordPrimTy hsLitType (HsInt64Prim _ _) = int64PrimTy hsLitType (HsWord64Prim _ _) = word64PrimTy hsLitType (HsInteger _ _ ty) = ty hsLitType (HsRat _ ty) = ty hsLitType (HsFloatPrim _) = floatPrimTy hsLitType (HsDoublePrim _) = doublePrimTy -- Overloaded literals. Here mainly because it uses isIntTy etc shortCutLit :: DynFlags -> OverLitVal -> TcType -> Maybe (HsExpr TcId) shortCutLit dflags (HsIntegral src i) ty | isIntTy ty && inIntRange dflags i = Just (HsLit (HsInt src i)) | isWordTy ty && inWordRange dflags i = Just (mkLit wordDataCon (HsWordPrim src i)) | isIntegerTy ty = Just (HsLit (HsInteger src i ty)) | otherwise = shortCutLit dflags (HsFractional (integralFractionalLit i)) ty -- The 'otherwise' case is important -- Consider (3 :: Float). Syntactically it looks like an IntLit, -- so we'll call shortCutIntLit, but of course it's a float -- This can make a big difference for programs with a lot of -- literals, compiled without -O shortCutLit _ (HsFractional f) ty | isFloatTy ty = Just (mkLit floatDataCon (HsFloatPrim f)) | isDoubleTy ty = Just (mkLit doubleDataCon (HsDoublePrim f)) | otherwise = Nothing shortCutLit _ (HsIsString src s) ty | isStringTy ty = Just (HsLit (HsString src s)) | otherwise = Nothing mkLit :: DataCon -> HsLit -> HsExpr Id mkLit con lit = HsApp (nlHsVar (dataConWrapId con)) (nlHsLit lit) ------------------------------ hsOverLitName :: OverLitVal -> Name -- Get the canonical 'fromX' name for a particular OverLitVal hsOverLitName (HsIntegral {}) = fromIntegerName hsOverLitName (HsFractional {}) = fromRationalName hsOverLitName (HsIsString {}) = fromStringName {- ************************************************************************ * * \subsection[BackSubst-HsBinds]{Running a substitution over @HsBinds@} * * ************************************************************************ The rest of the zonking is done *after* typechecking. The main zonking pass runs over the bindings a) to convert TcTyVars to TyVars etc, dereferencing any bindings etc b) convert unbound TcTyVar to Void c) convert each TcId to an Id by zonking its type The type variables are converted by binding mutable tyvars to immutable ones and then zonking as normal. The Ids are converted by binding them in the normal Tc envt; that way we maintain sharing; eg an Id is zonked at its binding site and they all occurrences of that Id point to the common zonked copy It's all pretty boring stuff, because HsSyn is such a large type, and the environment manipulation is tiresome. -} type UnboundTyVarZonker = TcTyVar-> TcM Type -- How to zonk an unbound type variable -- Note [Zonking the LHS of a RULE] data ZonkEnv = ZonkEnv UnboundTyVarZonker (TyVarEnv TyVar) -- (IdEnv Var) -- What variables are in scope -- Maps an Id or EvVar to its zonked version; both have the same Name -- Note that all evidence (coercion variables as well as dictionaries) -- are kept in the ZonkEnv -- Only *type* abstraction is done by side effect -- Is only consulted lazily; hence knot-tying instance Outputable ZonkEnv where ppr (ZonkEnv _ _ty_env var_env) = vcat (map ppr (varEnvElts var_env)) emptyZonkEnv :: ZonkEnv emptyZonkEnv = mkEmptyZonkEnv zonkTypeZapping mkEmptyZonkEnv :: UnboundTyVarZonker -> ZonkEnv mkEmptyZonkEnv zonker = ZonkEnv zonker emptyVarEnv emptyVarEnv extendIdZonkEnv :: ZonkEnv -> [Var] -> ZonkEnv extendIdZonkEnv (ZonkEnv zonk_ty ty_env id_env) ids = ZonkEnv zonk_ty ty_env (extendVarEnvList id_env [(id,id) | id <- ids]) extendIdZonkEnv1 :: ZonkEnv -> Var -> ZonkEnv extendIdZonkEnv1 (ZonkEnv zonk_ty ty_env id_env) id = ZonkEnv zonk_ty ty_env (extendVarEnv id_env id id) extendTyZonkEnv1 :: ZonkEnv -> TyVar -> ZonkEnv extendTyZonkEnv1 (ZonkEnv zonk_ty ty_env id_env) ty = ZonkEnv zonk_ty (extendVarEnv ty_env ty ty) id_env mkTyVarZonkEnv :: [TyVar] -> ZonkEnv mkTyVarZonkEnv tvs = ZonkEnv zonkTypeZapping (mkVarEnv [(tv,tv) | tv <- tvs]) emptyVarEnv setZonkType :: ZonkEnv -> UnboundTyVarZonker -> ZonkEnv setZonkType (ZonkEnv _ ty_env id_env) zonk_ty = ZonkEnv zonk_ty ty_env id_env zonkEnvIds :: ZonkEnv -> [Id] zonkEnvIds (ZonkEnv _ _ id_env) = varEnvElts id_env zonkIdOcc :: ZonkEnv -> TcId -> Id -- Ids defined in this module should be in the envt; -- ignore others. (Actually, data constructors are also -- not LocalVars, even when locally defined, but that is fine.) -- (Also foreign-imported things aren't currently in the ZonkEnv; -- that's ok because they don't need zonking.) -- -- Actually, Template Haskell works in 'chunks' of declarations, and -- an earlier chunk won't be in the 'env' that the zonking phase -- carries around. Instead it'll be in the tcg_gbl_env, already fully -- zonked. There's no point in looking it up there (except for error -- checking), and it's not conveniently to hand; hence the simple -- 'orElse' case in the LocalVar branch. -- -- Even without template splices, in module Main, the checking of -- 'main' is done as a separate chunk. zonkIdOcc (ZonkEnv _zonk_ty _ty_env env) id | isLocalVar id = lookupVarEnv env id `orElse` id | otherwise = id zonkIdOccs :: ZonkEnv -> [TcId] -> [Id] zonkIdOccs env ids = map (zonkIdOcc env) ids -- zonkIdBndr is used *after* typechecking to get the Id's type -- to its final form. The TyVarEnv give zonkIdBndr :: ZonkEnv -> TcId -> TcM Id zonkIdBndr env id = do ty' <- zonkTcTypeToType env (idType id) return (Id.setIdType id ty') zonkIdBndrs :: ZonkEnv -> [TcId] -> TcM [Id] zonkIdBndrs env ids = mapM (zonkIdBndr env) ids zonkTopBndrs :: [TcId] -> TcM [Id] zonkTopBndrs ids = zonkIdBndrs emptyZonkEnv ids zonkFieldOcc :: ZonkEnv -> FieldOcc TcId -> TcM (FieldOcc Id) zonkFieldOcc env (FieldOcc lbl sel) = fmap (FieldOcc lbl) $ zonkIdBndr env sel zonkEvBndrsX :: ZonkEnv -> [EvVar] -> TcM (ZonkEnv, [Var]) zonkEvBndrsX = mapAccumLM zonkEvBndrX zonkEvBndrX :: ZonkEnv -> EvVar -> TcM (ZonkEnv, EvVar) -- Works for dictionaries and coercions zonkEvBndrX env var = do { var' <- zonkEvBndr env var ; return (extendIdZonkEnv1 env var', var') } zonkEvBndr :: ZonkEnv -> EvVar -> TcM EvVar -- Works for dictionaries and coercions -- Does not extend the ZonkEnv zonkEvBndr env var = do { let var_ty = varType var ; ty <- {-# SCC "zonkEvBndr_zonkTcTypeToType" #-} zonkTcTypeToType env var_ty ; return (setVarType var ty) } zonkEvVarOcc :: ZonkEnv -> EvVar -> EvVar zonkEvVarOcc env v = zonkIdOcc env v zonkTyBndrsX :: ZonkEnv -> [TyVar] -> TcM (ZonkEnv, [TyVar]) zonkTyBndrsX = mapAccumLM zonkTyBndrX zonkTyBndrX :: ZonkEnv -> TyVar -> TcM (ZonkEnv, TyVar) -- This guarantees to return a TyVar (not a TcTyVar) -- then we add it to the envt, so all occurrences are replaced zonkTyBndrX env tv = do { ki <- zonkTcTypeToType env (tyVarKind tv) ; let tv' = mkTyVar (tyVarName tv) ki ; return (extendTyZonkEnv1 env tv', tv') } zonkTopExpr :: HsExpr TcId -> TcM (HsExpr Id) zonkTopExpr e = zonkExpr emptyZonkEnv e zonkTopLExpr :: LHsExpr TcId -> TcM (LHsExpr Id) zonkTopLExpr e = zonkLExpr emptyZonkEnv e zonkTopDecls :: Bag EvBind -> LHsBinds TcId -> Maybe (Located [LIE RdrName]) -> NameSet -> [LRuleDecl TcId] -> [LVectDecl TcId] -> [LTcSpecPrag] -> [LForeignDecl TcId] -> TcM ([Id], Bag EvBind, LHsBinds Id, [LForeignDecl Id], [LTcSpecPrag], [LRuleDecl Id], [LVectDecl Id]) zonkTopDecls ev_binds binds export_ies sig_ns rules vects imp_specs fords = do { (env1, ev_binds') <- zonkEvBinds emptyZonkEnv ev_binds -- Warn about missing signatures -- Do this only when we we have a type to offer ; warn_missing_sigs <- woptM Opt_WarnMissingSigs ; warn_only_exported <- woptM Opt_WarnMissingExportedSigs ; let export_occs = maybe emptyBag (listToBag . map (rdrNameOcc . ieName . unLoc) . unLoc) export_ies sig_warn | warn_only_exported = topSigWarnIfExported export_occs sig_ns | warn_missing_sigs = topSigWarn sig_ns | otherwise = noSigWarn ; (env2, binds') <- zonkRecMonoBinds env1 sig_warn binds -- Top level is implicitly recursive ; rules' <- zonkRules env2 rules ; vects' <- zonkVects env2 vects ; specs' <- zonkLTcSpecPrags env2 imp_specs ; fords' <- zonkForeignExports env2 fords ; return (zonkEnvIds env2, ev_binds', binds', fords', specs', rules', vects') } --------------------------------------------- zonkLocalBinds :: ZonkEnv -> HsLocalBinds TcId -> TcM (ZonkEnv, HsLocalBinds Id) zonkLocalBinds env EmptyLocalBinds = return (env, EmptyLocalBinds) zonkLocalBinds _ (HsValBinds (ValBindsIn {})) = panic "zonkLocalBinds" -- Not in typechecker output zonkLocalBinds env (HsValBinds vb@(ValBindsOut binds sigs)) = do { warn_missing_sigs <- woptM Opt_WarnMissingLocalSigs ; let sig_warn | not warn_missing_sigs = noSigWarn | otherwise = localSigWarn sig_ns sig_ns = getTypeSigNames vb ; (env1, new_binds) <- go env sig_warn binds ; return (env1, HsValBinds (ValBindsOut new_binds sigs)) } where go env _ [] = return (env, []) go env sig_warn ((r,b):bs) = do { (env1, b') <- zonkRecMonoBinds env sig_warn b ; (env2, bs') <- go env1 sig_warn bs ; return (env2, (r,b'):bs') } zonkLocalBinds env (HsIPBinds (IPBinds binds dict_binds)) = do new_binds <- mapM (wrapLocM zonk_ip_bind) binds let env1 = extendIdZonkEnv env [ n | L _ (IPBind (Right n) _) <- new_binds] (env2, new_dict_binds) <- zonkTcEvBinds env1 dict_binds return (env2, HsIPBinds (IPBinds new_binds new_dict_binds)) where zonk_ip_bind (IPBind n e) = do n' <- mapIPNameTc (zonkIdBndr env) n e' <- zonkLExpr env e return (IPBind n' e') --------------------------------------------- zonkRecMonoBinds :: ZonkEnv -> SigWarn -> LHsBinds TcId -> TcM (ZonkEnv, LHsBinds Id) zonkRecMonoBinds env sig_warn binds = fixM (\ ~(_, new_binds) -> do { let env1 = extendIdZonkEnv env (collectHsBindsBinders new_binds) ; binds' <- zonkMonoBinds env1 sig_warn binds ; return (env1, binds') }) --------------------------------------------- type SigWarn = Bool -> [Id] -> TcM () -- Missing-signature warning -- The Bool is True for an AbsBinds, False otherwise noSigWarn :: SigWarn noSigWarn _ _ = return () topSigWarnIfExported :: Bag OccName -> NameSet -> SigWarn topSigWarnIfExported exported sig_ns _ ids = mapM_ (topSigWarnIdIfExported exported sig_ns) ids topSigWarnIdIfExported :: Bag OccName -> NameSet -> Id -> TcM () topSigWarnIdIfExported exported sig_ns id | getOccName id `elemBag` exported = topSigWarnId sig_ns id | otherwise = return () topSigWarn :: NameSet -> SigWarn topSigWarn sig_ns _ ids = mapM_ (topSigWarnId sig_ns) ids topSigWarnId :: NameSet -> Id -> TcM () -- The NameSet is the Ids that *lack* a signature -- We have to do it this way round because there are -- lots of top-level bindings that are generated by GHC -- and that don't have signatures topSigWarnId sig_ns id | idName id `elemNameSet` sig_ns = warnMissingSig msg id | otherwise = return () where msg = ptext (sLit "Top-level binding with no type signature:") localSigWarn :: NameSet -> SigWarn localSigWarn sig_ns is_abs_bind ids | not is_abs_bind = return () | otherwise = mapM_ (localSigWarnId sig_ns) ids localSigWarnId :: NameSet -> Id -> TcM () -- NameSet are the Ids that *have* type signatures localSigWarnId sig_ns id | not (isSigmaTy (idType id)) = return () | idName id `elemNameSet` sig_ns = return () | otherwise = warnMissingSig msg id where msg = ptext (sLit "Polymorphic local binding with no type signature:") warnMissingSig :: SDoc -> Id -> TcM () warnMissingSig msg id = do { env0 <- tcInitTidyEnv ; let (env1, tidy_ty) = tidyOpenType env0 (idType id) ; addWarnTcM (env1, mk_msg tidy_ty) } where mk_msg ty = sep [ msg, nest 2 $ pprPrefixName (idName id) <+> dcolon <+> ppr ty ] --------------------------------------------- zonkMonoBinds :: ZonkEnv -> SigWarn -> LHsBinds TcId -> TcM (LHsBinds Id) zonkMonoBinds env sig_warn binds = mapBagM (zonk_lbind env sig_warn) binds zonk_lbind :: ZonkEnv -> SigWarn -> LHsBind TcId -> TcM (LHsBind Id) zonk_lbind env sig_warn = wrapLocM (zonk_bind env sig_warn) zonk_bind :: ZonkEnv -> SigWarn -> HsBind TcId -> TcM (HsBind Id) zonk_bind env sig_warn bind@(PatBind { pat_lhs = pat, pat_rhs = grhss, pat_rhs_ty = ty}) = do { (_env, new_pat) <- zonkPat env pat -- Env already extended ; sig_warn False (collectPatBinders new_pat) ; new_grhss <- zonkGRHSs env zonkLExpr grhss ; new_ty <- zonkTcTypeToType env ty ; return (bind { pat_lhs = new_pat, pat_rhs = new_grhss, pat_rhs_ty = new_ty }) } zonk_bind env sig_warn (VarBind { var_id = var, var_rhs = expr, var_inline = inl }) = do { new_var <- zonkIdBndr env var ; sig_warn False [new_var] ; new_expr <- zonkLExpr env expr ; return (VarBind { var_id = new_var, var_rhs = new_expr, var_inline = inl }) } zonk_bind env sig_warn bind@(FunBind { fun_id = L loc var, fun_matches = ms , fun_co_fn = co_fn }) = do { new_var <- zonkIdBndr env var ; sig_warn False [new_var] ; (env1, new_co_fn) <- zonkCoFn env co_fn ; new_ms <- zonkMatchGroup env1 zonkLExpr ms ; return (bind { fun_id = L loc new_var, fun_matches = new_ms , fun_co_fn = new_co_fn }) } zonk_bind env sig_warn (AbsBinds { abs_tvs = tyvars, abs_ev_vars = evs , abs_ev_binds = ev_binds , abs_exports = exports , abs_binds = val_binds }) = ASSERT( all isImmutableTyVar tyvars ) do { (env0, new_tyvars) <- zonkTyBndrsX env tyvars ; (env1, new_evs) <- zonkEvBndrsX env0 evs ; (env2, new_ev_binds) <- zonkTcEvBinds_s env1 ev_binds ; (new_val_bind, new_exports) <- fixM $ \ ~(new_val_binds, _) -> do { let env3 = extendIdZonkEnv env2 (collectHsBindsBinders new_val_binds) ; new_val_binds <- zonkMonoBinds env3 noSigWarn val_binds ; new_exports <- mapM (zonkExport env3) exports ; return (new_val_binds, new_exports) } ; sig_warn True (map abe_poly new_exports) ; return (AbsBinds { abs_tvs = new_tyvars, abs_ev_vars = new_evs , abs_ev_binds = new_ev_binds , abs_exports = new_exports, abs_binds = new_val_bind }) } where zonkExport env (ABE{ abe_wrap = wrap, abe_poly = poly_id , abe_mono = mono_id, abe_prags = prags }) = do new_poly_id <- zonkIdBndr env poly_id (_, new_wrap) <- zonkCoFn env wrap new_prags <- zonkSpecPrags env prags return (ABE{ abe_wrap = new_wrap, abe_poly = new_poly_id , abe_mono = zonkIdOcc env mono_id , abe_prags = new_prags }) zonk_bind env _sig_warn (PatSynBind bind@(PSB { psb_id = L loc id , psb_args = details , psb_def = lpat , psb_dir = dir })) = do { id' <- zonkIdBndr env id ; details' <- zonkPatSynDetails env details ;(env1, lpat') <- zonkPat env lpat ; (_env2, dir') <- zonkPatSynDir env1 dir ; return $ PatSynBind $ bind { psb_id = L loc id' , psb_args = details' , psb_def = lpat' , psb_dir = dir' } } zonkPatSynDetails :: ZonkEnv -> HsPatSynDetails (Located TcId) -> TcM (HsPatSynDetails (Located Id)) zonkPatSynDetails env = traverse (wrapLocM $ zonkIdBndr env) zonkPatSynDir :: ZonkEnv -> HsPatSynDir TcId -> TcM (ZonkEnv, HsPatSynDir Id) zonkPatSynDir env Unidirectional = return (env, Unidirectional) zonkPatSynDir env ImplicitBidirectional = return (env, ImplicitBidirectional) zonkPatSynDir env (ExplicitBidirectional mg) = do mg' <- zonkMatchGroup env zonkLExpr mg return (env, ExplicitBidirectional mg') zonkSpecPrags :: ZonkEnv -> TcSpecPrags -> TcM TcSpecPrags zonkSpecPrags _ IsDefaultMethod = return IsDefaultMethod zonkSpecPrags env (SpecPrags ps) = do { ps' <- zonkLTcSpecPrags env ps ; return (SpecPrags ps') } zonkLTcSpecPrags :: ZonkEnv -> [LTcSpecPrag] -> TcM [LTcSpecPrag] zonkLTcSpecPrags env ps = mapM zonk_prag ps where zonk_prag (L loc (SpecPrag id co_fn inl)) = do { (_, co_fn') <- zonkCoFn env co_fn ; return (L loc (SpecPrag (zonkIdOcc env id) co_fn' inl)) } {- ************************************************************************ * * \subsection[BackSubst-Match-GRHSs]{Match and GRHSs} * * ************************************************************************ -} zonkMatchGroup :: ZonkEnv -> (ZonkEnv -> Located (body TcId) -> TcM (Located (body Id))) -> MatchGroup TcId (Located (body TcId)) -> TcM (MatchGroup Id (Located (body Id))) zonkMatchGroup env zBody (MG { mg_alts = L l ms, mg_arg_tys = arg_tys , mg_res_ty = res_ty, mg_origin = origin }) = do { ms' <- mapM (zonkMatch env zBody) ms ; arg_tys' <- zonkTcTypeToTypes env arg_tys ; res_ty' <- zonkTcTypeToType env res_ty ; return (MG { mg_alts = L l ms', mg_arg_tys = arg_tys' , mg_res_ty = res_ty', mg_origin = origin }) } zonkMatch :: ZonkEnv -> (ZonkEnv -> Located (body TcId) -> TcM (Located (body Id))) -> LMatch TcId (Located (body TcId)) -> TcM (LMatch Id (Located (body Id))) zonkMatch env zBody (L loc (Match mf pats _ grhss)) = do { (env1, new_pats) <- zonkPats env pats ; new_grhss <- zonkGRHSs env1 zBody grhss ; return (L loc (Match mf new_pats Nothing new_grhss)) } ------------------------------------------------------------------------- zonkGRHSs :: ZonkEnv -> (ZonkEnv -> Located (body TcId) -> TcM (Located (body Id))) -> GRHSs TcId (Located (body TcId)) -> TcM (GRHSs Id (Located (body Id))) zonkGRHSs env zBody (GRHSs grhss (L l binds)) = do (new_env, new_binds) <- zonkLocalBinds env binds let zonk_grhs (GRHS guarded rhs) = do (env2, new_guarded) <- zonkStmts new_env zonkLExpr guarded new_rhs <- zBody env2 rhs return (GRHS new_guarded new_rhs) new_grhss <- mapM (wrapLocM zonk_grhs) grhss return (GRHSs new_grhss (L l new_binds)) {- ************************************************************************ * * \subsection[BackSubst-HsExpr]{Running a zonkitution over a TypeCheckedExpr} * * ************************************************************************ -} zonkLExprs :: ZonkEnv -> [LHsExpr TcId] -> TcM [LHsExpr Id] zonkLExpr :: ZonkEnv -> LHsExpr TcId -> TcM (LHsExpr Id) zonkExpr :: ZonkEnv -> HsExpr TcId -> TcM (HsExpr Id) zonkLExprs env exprs = mapM (zonkLExpr env) exprs zonkLExpr env expr = wrapLocM (zonkExpr env) expr zonkExpr env (HsVar (L l id)) = return (HsVar (L l (zonkIdOcc env id))) zonkExpr _ (HsIPVar id) = return (HsIPVar id) zonkExpr _ (HsOverLabel l) = return (HsOverLabel l) zonkExpr env (HsLit (HsRat f ty)) = do new_ty <- zonkTcTypeToType env ty return (HsLit (HsRat f new_ty)) zonkExpr _ (HsLit lit) = return (HsLit lit) zonkExpr env (HsOverLit lit) = do { lit' <- zonkOverLit env lit ; return (HsOverLit lit') } zonkExpr env (HsLam matches) = do new_matches <- zonkMatchGroup env zonkLExpr matches return (HsLam new_matches) zonkExpr env (HsLamCase arg matches) = do new_arg <- zonkTcTypeToType env arg new_matches <- zonkMatchGroup env zonkLExpr matches return (HsLamCase new_arg new_matches) zonkExpr env (HsApp e1 e2) = do new_e1 <- zonkLExpr env e1 new_e2 <- zonkLExpr env e2 return (HsApp new_e1 new_e2) zonkExpr _ e@(HsRnBracketOut _ _) = pprPanic "zonkExpr: HsRnBracketOut" (ppr e) zonkExpr env (HsTcBracketOut body bs) = do bs' <- mapM zonk_b bs return (HsTcBracketOut body bs') where zonk_b (PendingTcSplice n e) = do e' <- zonkLExpr env e return (PendingTcSplice n e') zonkExpr _ (HsSpliceE s) = WARN( True, ppr s ) -- Should not happen return (HsSpliceE s) zonkExpr env (OpApp e1 op fixity e2) = do new_e1 <- zonkLExpr env e1 new_op <- zonkLExpr env op new_e2 <- zonkLExpr env e2 return (OpApp new_e1 new_op fixity new_e2) zonkExpr env (NegApp expr op) = do new_expr <- zonkLExpr env expr new_op <- zonkExpr env op return (NegApp new_expr new_op) zonkExpr env (HsPar e) = do new_e <- zonkLExpr env e return (HsPar new_e) zonkExpr env (SectionL expr op) = do new_expr <- zonkLExpr env expr new_op <- zonkLExpr env op return (SectionL new_expr new_op) zonkExpr env (SectionR op expr) = do new_op <- zonkLExpr env op new_expr <- zonkLExpr env expr return (SectionR new_op new_expr) zonkExpr env (ExplicitTuple tup_args boxed) = do { new_tup_args <- mapM zonk_tup_arg tup_args ; return (ExplicitTuple new_tup_args boxed) } where zonk_tup_arg (L l (Present e)) = do { e' <- zonkLExpr env e ; return (L l (Present e')) } zonk_tup_arg (L l (Missing t)) = do { t' <- zonkTcTypeToType env t ; return (L l (Missing t')) } zonkExpr env (HsCase expr ms) = do new_expr <- zonkLExpr env expr new_ms <- zonkMatchGroup env zonkLExpr ms return (HsCase new_expr new_ms) zonkExpr env (HsIf e0 e1 e2 e3) = do { new_e0 <- fmapMaybeM (zonkExpr env) e0 ; new_e1 <- zonkLExpr env e1 ; new_e2 <- zonkLExpr env e2 ; new_e3 <- zonkLExpr env e3 ; return (HsIf new_e0 new_e1 new_e2 new_e3) } zonkExpr env (HsMultiIf ty alts) = do { alts' <- mapM (wrapLocM zonk_alt) alts ; ty' <- zonkTcTypeToType env ty ; return $ HsMultiIf ty' alts' } where zonk_alt (GRHS guard expr) = do { (env', guard') <- zonkStmts env zonkLExpr guard ; expr' <- zonkLExpr env' expr ; return $ GRHS guard' expr' } zonkExpr env (HsLet (L l binds) expr) = do (new_env, new_binds) <- zonkLocalBinds env binds new_expr <- zonkLExpr new_env expr return (HsLet (L l new_binds) new_expr) zonkExpr env (HsDo do_or_lc (L l stmts) ty) = do (_, new_stmts) <- zonkStmts env zonkLExpr stmts new_ty <- zonkTcTypeToType env ty return (HsDo do_or_lc (L l new_stmts) new_ty) zonkExpr env (ExplicitList ty wit exprs) = do new_ty <- zonkTcTypeToType env ty new_wit <- zonkWit env wit new_exprs <- zonkLExprs env exprs return (ExplicitList new_ty new_wit new_exprs) where zonkWit _ Nothing = return Nothing zonkWit env (Just fln) = do new_fln <- zonkExpr env fln return (Just new_fln) zonkExpr env (ExplicitPArr ty exprs) = do new_ty <- zonkTcTypeToType env ty new_exprs <- zonkLExprs env exprs return (ExplicitPArr new_ty new_exprs) zonkExpr env expr@(RecordCon { rcon_con_expr = con_expr, rcon_flds = rbinds }) = do { new_con_expr <- zonkExpr env con_expr ; new_rbinds <- zonkRecFields env rbinds ; return (expr { rcon_con_expr = new_con_expr , rcon_flds = new_rbinds }) } zonkExpr env (RecordUpd { rupd_expr = expr, rupd_flds = rbinds , rupd_cons = cons, rupd_in_tys = in_tys , rupd_out_tys = out_tys, rupd_wrap = req_wrap }) = do { new_expr <- zonkLExpr env expr ; new_in_tys <- mapM (zonkTcTypeToType env) in_tys ; new_out_tys <- mapM (zonkTcTypeToType env) out_tys ; new_rbinds <- zonkRecUpdFields env rbinds ; (_, new_recwrap) <- zonkCoFn env req_wrap ; return (RecordUpd { rupd_expr = new_expr, rupd_flds = new_rbinds , rupd_cons = cons, rupd_in_tys = new_in_tys , rupd_out_tys = new_out_tys, rupd_wrap = new_recwrap }) } zonkExpr env (ExprWithTySigOut e ty) = do { e' <- zonkLExpr env e ; return (ExprWithTySigOut e' ty) } zonkExpr _ (ExprWithTySig _ _ _) = panic "zonkExpr env:ExprWithTySig" zonkExpr env (ArithSeq expr wit info) = do new_expr <- zonkExpr env expr new_wit <- zonkWit env wit new_info <- zonkArithSeq env info return (ArithSeq new_expr new_wit new_info) where zonkWit _ Nothing = return Nothing zonkWit env (Just fln) = do new_fln <- zonkExpr env fln return (Just new_fln) zonkExpr env (PArrSeq expr info) = do new_expr <- zonkExpr env expr new_info <- zonkArithSeq env info return (PArrSeq new_expr new_info) zonkExpr env (HsSCC src lbl expr) = do new_expr <- zonkLExpr env expr return (HsSCC src lbl new_expr) zonkExpr env (HsTickPragma src info expr) = do new_expr <- zonkLExpr env expr return (HsTickPragma src info new_expr) -- hdaume: core annotations zonkExpr env (HsCoreAnn src lbl expr) = do new_expr <- zonkLExpr env expr return (HsCoreAnn src lbl new_expr) -- arrow notation extensions zonkExpr env (HsProc pat body) = do { (env1, new_pat) <- zonkPat env pat ; new_body <- zonkCmdTop env1 body ; return (HsProc new_pat new_body) } -- StaticPointers extension zonkExpr env (HsStatic expr) = HsStatic <$> zonkLExpr env expr zonkExpr env (HsWrap co_fn expr) = do (env1, new_co_fn) <- zonkCoFn env co_fn new_expr <- zonkExpr env1 expr return (HsWrap new_co_fn new_expr) zonkExpr _ (HsUnboundVar v) = return (HsUnboundVar v) zonkExpr _ expr = pprPanic "zonkExpr" (ppr expr) ------------------------------------------------------------------------- zonkLCmd :: ZonkEnv -> LHsCmd TcId -> TcM (LHsCmd Id) zonkCmd :: ZonkEnv -> HsCmd TcId -> TcM (HsCmd Id) zonkLCmd env cmd = wrapLocM (zonkCmd env) cmd zonkCmd env (HsCmdCast co cmd) = do { co' <- zonkTcCoToCo env co ; cmd' <- zonkCmd env cmd ; return (HsCmdCast co' cmd') } zonkCmd env (HsCmdArrApp e1 e2 ty ho rl) = do new_e1 <- zonkLExpr env e1 new_e2 <- zonkLExpr env e2 new_ty <- zonkTcTypeToType env ty return (HsCmdArrApp new_e1 new_e2 new_ty ho rl) zonkCmd env (HsCmdArrForm op fixity args) = do new_op <- zonkLExpr env op new_args <- mapM (zonkCmdTop env) args return (HsCmdArrForm new_op fixity new_args) zonkCmd env (HsCmdApp c e) = do new_c <- zonkLCmd env c new_e <- zonkLExpr env e return (HsCmdApp new_c new_e) zonkCmd env (HsCmdLam matches) = do new_matches <- zonkMatchGroup env zonkLCmd matches return (HsCmdLam new_matches) zonkCmd env (HsCmdPar c) = do new_c <- zonkLCmd env c return (HsCmdPar new_c) zonkCmd env (HsCmdCase expr ms) = do new_expr <- zonkLExpr env expr new_ms <- zonkMatchGroup env zonkLCmd ms return (HsCmdCase new_expr new_ms) zonkCmd env (HsCmdIf eCond ePred cThen cElse) = do { new_eCond <- fmapMaybeM (zonkExpr env) eCond ; new_ePred <- zonkLExpr env ePred ; new_cThen <- zonkLCmd env cThen ; new_cElse <- zonkLCmd env cElse ; return (HsCmdIf new_eCond new_ePred new_cThen new_cElse) } zonkCmd env (HsCmdLet (L l binds) cmd) = do (new_env, new_binds) <- zonkLocalBinds env binds new_cmd <- zonkLCmd new_env cmd return (HsCmdLet (L l new_binds) new_cmd) zonkCmd env (HsCmdDo (L l stmts) ty) = do (_, new_stmts) <- zonkStmts env zonkLCmd stmts new_ty <- zonkTcTypeToType env ty return (HsCmdDo (L l new_stmts) new_ty) zonkCmdTop :: ZonkEnv -> LHsCmdTop TcId -> TcM (LHsCmdTop Id) zonkCmdTop env cmd = wrapLocM (zonk_cmd_top env) cmd zonk_cmd_top :: ZonkEnv -> HsCmdTop TcId -> TcM (HsCmdTop Id) zonk_cmd_top env (HsCmdTop cmd stack_tys ty ids) = do new_cmd <- zonkLCmd env cmd new_stack_tys <- zonkTcTypeToType env stack_tys new_ty <- zonkTcTypeToType env ty new_ids <- mapSndM (zonkExpr env) ids return (HsCmdTop new_cmd new_stack_tys new_ty new_ids) ------------------------------------------------------------------------- zonkCoFn :: ZonkEnv -> HsWrapper -> TcM (ZonkEnv, HsWrapper) zonkCoFn env WpHole = return (env, WpHole) zonkCoFn env (WpCompose c1 c2) = do { (env1, c1') <- zonkCoFn env c1 ; (env2, c2') <- zonkCoFn env1 c2 ; return (env2, WpCompose c1' c2') } zonkCoFn env (WpFun c1 c2 t1 t2) = do { (env1, c1') <- zonkCoFn env c1 ; (env2, c2') <- zonkCoFn env1 c2 ; t1' <- zonkTcTypeToType env2 t1 ; t2' <- zonkTcTypeToType env2 t2 ; return (env2, WpFun c1' c2' t1' t2') } zonkCoFn env (WpCast co) = do { co' <- zonkTcCoToCo env co ; return (env, WpCast co') } zonkCoFn env (WpEvLam ev) = do { (env', ev') <- zonkEvBndrX env ev ; return (env', WpEvLam ev') } zonkCoFn env (WpEvApp arg) = do { arg' <- zonkEvTerm env arg ; return (env, WpEvApp arg') } zonkCoFn env (WpTyLam tv) = ASSERT( isImmutableTyVar tv ) do { (env', tv') <- zonkTyBndrX env tv ; return (env', WpTyLam tv') } zonkCoFn env (WpTyApp ty) = do { ty' <- zonkTcTypeToType env ty ; return (env, WpTyApp ty') } zonkCoFn env (WpLet bs) = do { (env1, bs') <- zonkTcEvBinds env bs ; return (env1, WpLet bs') } ------------------------------------------------------------------------- zonkOverLit :: ZonkEnv -> HsOverLit TcId -> TcM (HsOverLit Id) zonkOverLit env lit@(OverLit { ol_witness = e, ol_type = ty }) = do { ty' <- zonkTcTypeToType env ty ; e' <- zonkExpr env e ; return (lit { ol_witness = e', ol_type = ty' }) } ------------------------------------------------------------------------- zonkArithSeq :: ZonkEnv -> ArithSeqInfo TcId -> TcM (ArithSeqInfo Id) zonkArithSeq env (From e) = do new_e <- zonkLExpr env e return (From new_e) zonkArithSeq env (FromThen e1 e2) = do new_e1 <- zonkLExpr env e1 new_e2 <- zonkLExpr env e2 return (FromThen new_e1 new_e2) zonkArithSeq env (FromTo e1 e2) = do new_e1 <- zonkLExpr env e1 new_e2 <- zonkLExpr env e2 return (FromTo new_e1 new_e2) zonkArithSeq env (FromThenTo e1 e2 e3) = do new_e1 <- zonkLExpr env e1 new_e2 <- zonkLExpr env e2 new_e3 <- zonkLExpr env e3 return (FromThenTo new_e1 new_e2 new_e3) ------------------------------------------------------------------------- zonkStmts :: ZonkEnv -> (ZonkEnv -> Located (body TcId) -> TcM (Located (body Id))) -> [LStmt TcId (Located (body TcId))] -> TcM (ZonkEnv, [LStmt Id (Located (body Id))]) zonkStmts env _ [] = return (env, []) zonkStmts env zBody (s:ss) = do { (env1, s') <- wrapLocSndM (zonkStmt env zBody) s ; (env2, ss') <- zonkStmts env1 zBody ss ; return (env2, s' : ss') } zonkStmt :: ZonkEnv -> (ZonkEnv -> Located (body TcId) -> TcM (Located (body Id))) -> Stmt TcId (Located (body TcId)) -> TcM (ZonkEnv, Stmt Id (Located (body Id))) zonkStmt env _ (ParStmt stmts_w_bndrs mzip_op bind_op) = do { new_stmts_w_bndrs <- mapM zonk_branch stmts_w_bndrs ; let new_binders = [b | ParStmtBlock _ bs _ <- new_stmts_w_bndrs, b <- bs] env1 = extendIdZonkEnv env new_binders ; new_mzip <- zonkExpr env1 mzip_op ; new_bind <- zonkExpr env1 bind_op ; return (env1, ParStmt new_stmts_w_bndrs new_mzip new_bind) } where zonk_branch (ParStmtBlock stmts bndrs return_op) = do { (env1, new_stmts) <- zonkStmts env zonkLExpr stmts ; new_return <- zonkExpr env1 return_op ; return (ParStmtBlock new_stmts (zonkIdOccs env1 bndrs) new_return) } zonkStmt env zBody (RecStmt { recS_stmts = segStmts, recS_later_ids = lvs, recS_rec_ids = rvs , recS_ret_fn = ret_id, recS_mfix_fn = mfix_id, recS_bind_fn = bind_id , recS_later_rets = later_rets, recS_rec_rets = rec_rets , recS_ret_ty = ret_ty }) = do { new_rvs <- zonkIdBndrs env rvs ; new_lvs <- zonkIdBndrs env lvs ; new_ret_ty <- zonkTcTypeToType env ret_ty ; new_ret_id <- zonkExpr env ret_id ; new_mfix_id <- zonkExpr env mfix_id ; new_bind_id <- zonkExpr env bind_id ; let env1 = extendIdZonkEnv env new_rvs ; (env2, new_segStmts) <- zonkStmts env1 zBody segStmts -- Zonk the ret-expressions in an envt that -- has the polymorphic bindings in the envt ; new_later_rets <- mapM (zonkExpr env2) later_rets ; new_rec_rets <- mapM (zonkExpr env2) rec_rets ; return (extendIdZonkEnv env new_lvs, -- Only the lvs are needed RecStmt { recS_stmts = new_segStmts, recS_later_ids = new_lvs , recS_rec_ids = new_rvs, recS_ret_fn = new_ret_id , recS_mfix_fn = new_mfix_id, recS_bind_fn = new_bind_id , recS_later_rets = new_later_rets , recS_rec_rets = new_rec_rets, recS_ret_ty = new_ret_ty }) } zonkStmt env zBody (BodyStmt body then_op guard_op ty) = do new_body <- zBody env body new_then <- zonkExpr env then_op new_guard <- zonkExpr env guard_op new_ty <- zonkTcTypeToType env ty return (env, BodyStmt new_body new_then new_guard new_ty) zonkStmt env zBody (LastStmt body noret ret_op) = do new_body <- zBody env body new_ret <- zonkExpr env ret_op return (env, LastStmt new_body noret new_ret) zonkStmt env _ (TransStmt { trS_stmts = stmts, trS_bndrs = binderMap , trS_by = by, trS_form = form, trS_using = using , trS_ret = return_op, trS_bind = bind_op, trS_fmap = liftM_op }) = do { (env', stmts') <- zonkStmts env zonkLExpr stmts ; binderMap' <- mapM (zonkBinderMapEntry env') binderMap ; by' <- fmapMaybeM (zonkLExpr env') by ; using' <- zonkLExpr env using ; return_op' <- zonkExpr env' return_op ; bind_op' <- zonkExpr env' bind_op ; liftM_op' <- zonkExpr env' liftM_op ; let env'' = extendIdZonkEnv env' (map snd binderMap') ; return (env'', TransStmt { trS_stmts = stmts', trS_bndrs = binderMap' , trS_by = by', trS_form = form, trS_using = using' , trS_ret = return_op', trS_bind = bind_op', trS_fmap = liftM_op' }) } where zonkBinderMapEntry env (oldBinder, newBinder) = do let oldBinder' = zonkIdOcc env oldBinder newBinder' <- zonkIdBndr env newBinder return (oldBinder', newBinder') zonkStmt env _ (LetStmt (L l binds)) = do (env1, new_binds) <- zonkLocalBinds env binds return (env1, LetStmt (L l new_binds)) zonkStmt env zBody (BindStmt pat body bind_op fail_op) = do { new_body <- zBody env body ; (env1, new_pat) <- zonkPat env pat ; new_bind <- zonkExpr env bind_op ; new_fail <- zonkExpr env fail_op ; return (env1, BindStmt new_pat new_body new_bind new_fail) } zonkStmt env _zBody (ApplicativeStmt args mb_join body_ty) = do { (env', args') <- zonk_args env args ; new_mb_join <- traverse (zonkExpr env) mb_join ; new_body_ty <- zonkTcTypeToType env' body_ty ; return (env', ApplicativeStmt args' new_mb_join new_body_ty) } where zonk_args env [] = return (env, []) zonk_args env ((op, arg) : groups) = do { (env1, arg') <- zonk_arg env arg ; op' <- zonkExpr env1 op ; (env2, ss) <- zonk_args env1 groups ; return (env2, (op', arg') : ss) } zonk_arg env (ApplicativeArgOne pat expr) = do { (env1, new_pat) <- zonkPat env pat ; new_expr <- zonkLExpr env expr ; return (env1, ApplicativeArgOne new_pat new_expr) } zonk_arg env (ApplicativeArgMany stmts ret pat) = do { (env1, new_stmts) <- zonkStmts env zonkLExpr stmts ; new_ret <- zonkExpr env1 ret ; (env2, new_pat) <- zonkPat env pat ; return (env2, ApplicativeArgMany new_stmts new_ret new_pat) } ------------------------------------------------------------------------- zonkRecFields :: ZonkEnv -> HsRecordBinds TcId -> TcM (HsRecordBinds TcId) zonkRecFields env (HsRecFields flds dd) = do { flds' <- mapM zonk_rbind flds ; return (HsRecFields flds' dd) } where zonk_rbind (L l fld) = do { new_id <- wrapLocM (zonkFieldOcc env) (hsRecFieldLbl fld) ; new_expr <- zonkLExpr env (hsRecFieldArg fld) ; return (L l (fld { hsRecFieldLbl = new_id , hsRecFieldArg = new_expr })) } zonkRecUpdFields :: ZonkEnv -> [LHsRecUpdField TcId] -> TcM [LHsRecUpdField TcId] zonkRecUpdFields env = mapM zonk_rbind where zonk_rbind (L l fld) = do { new_id <- wrapLocM (zonkFieldOcc env) (hsRecUpdFieldOcc fld) ; new_expr <- zonkLExpr env (hsRecFieldArg fld) ; return (L l (fld { hsRecFieldLbl = fmap ambiguousFieldOcc new_id , hsRecFieldArg = new_expr })) } ------------------------------------------------------------------------- mapIPNameTc :: (a -> TcM b) -> Either (Located HsIPName) a -> TcM (Either (Located HsIPName) b) mapIPNameTc _ (Left x) = return (Left x) mapIPNameTc f (Right x) = do r <- f x return (Right r) {- ************************************************************************ * * \subsection[BackSubst-Pats]{Patterns} * * ************************************************************************ -} zonkPat :: ZonkEnv -> OutPat TcId -> TcM (ZonkEnv, OutPat Id) -- Extend the environment as we go, because it's possible for one -- pattern to bind something that is used in another (inside or -- to the right) zonkPat env pat = wrapLocSndM (zonk_pat env) pat zonk_pat :: ZonkEnv -> Pat TcId -> TcM (ZonkEnv, Pat Id) zonk_pat env (ParPat p) = do { (env', p') <- zonkPat env p ; return (env', ParPat p') } zonk_pat env (WildPat ty) = do { ty' <- zonkTcTypeToType env ty ; return (env, WildPat ty') } zonk_pat env (VarPat (L l v)) = do { v' <- zonkIdBndr env v ; return (extendIdZonkEnv1 env v', VarPat (L l v')) } zonk_pat env (LazyPat pat) = do { (env', pat') <- zonkPat env pat ; return (env', LazyPat pat') } zonk_pat env (BangPat pat) = do { (env', pat') <- zonkPat env pat ; return (env', BangPat pat') } zonk_pat env (AsPat (L loc v) pat) = do { v' <- zonkIdBndr env v ; (env', pat') <- zonkPat (extendIdZonkEnv1 env v') pat ; return (env', AsPat (L loc v') pat') } zonk_pat env (ViewPat expr pat ty) = do { expr' <- zonkLExpr env expr ; (env', pat') <- zonkPat env pat ; ty' <- zonkTcTypeToType env ty ; return (env', ViewPat expr' pat' ty') } zonk_pat env (ListPat pats ty Nothing) = do { ty' <- zonkTcTypeToType env ty ; (env', pats') <- zonkPats env pats ; return (env', ListPat pats' ty' Nothing) } zonk_pat env (ListPat pats ty (Just (ty2,wit))) = do { wit' <- zonkExpr env wit ; ty2' <- zonkTcTypeToType env ty2 ; ty' <- zonkTcTypeToType env ty ; (env', pats') <- zonkPats env pats ; return (env', ListPat pats' ty' (Just (ty2',wit'))) } zonk_pat env (PArrPat pats ty) = do { ty' <- zonkTcTypeToType env ty ; (env', pats') <- zonkPats env pats ; return (env', PArrPat pats' ty') } zonk_pat env (TuplePat pats boxed tys) = do { tys' <- mapM (zonkTcTypeToType env) tys ; (env', pats') <- zonkPats env pats ; return (env', TuplePat pats' boxed tys') } zonk_pat env p@(ConPatOut { pat_arg_tys = tys, pat_tvs = tyvars , pat_dicts = evs, pat_binds = binds , pat_args = args, pat_wrap = wrapper }) = ASSERT( all isImmutableTyVar tyvars ) do { new_tys <- mapM (zonkTcTypeToType env) tys ; (env0, new_tyvars) <- zonkTyBndrsX env tyvars -- Must zonk the existential variables, because their -- /kind/ need potential zonking. -- cf typecheck/should_compile/tc221.hs ; (env1, new_evs) <- zonkEvBndrsX env0 evs ; (env2, new_binds) <- zonkTcEvBinds env1 binds ; (env3, new_wrapper) <- zonkCoFn env2 wrapper ; (env', new_args) <- zonkConStuff env3 args ; return (env', p { pat_arg_tys = new_tys, pat_tvs = new_tyvars, pat_dicts = new_evs, pat_binds = new_binds, pat_args = new_args, pat_wrap = new_wrapper}) } zonk_pat env (LitPat lit) = return (env, LitPat lit) zonk_pat env (SigPatOut pat ty) = do { ty' <- zonkTcTypeToType env ty ; (env', pat') <- zonkPat env pat ; return (env', SigPatOut pat' ty') } zonk_pat env (NPat (L l lit) mb_neg eq_expr) = do { lit' <- zonkOverLit env lit ; mb_neg' <- fmapMaybeM (zonkExpr env) mb_neg ; eq_expr' <- zonkExpr env eq_expr ; return (env, NPat (L l lit') mb_neg' eq_expr') } zonk_pat env (NPlusKPat (L loc n) (L l lit) e1 e2) = do { n' <- zonkIdBndr env n ; lit' <- zonkOverLit env lit ; e1' <- zonkExpr env e1 ; e2' <- zonkExpr env e2 ; return (extendIdZonkEnv1 env n', NPlusKPat (L loc n') (L l lit') e1' e2') } zonk_pat env (CoPat co_fn pat ty) = do { (env', co_fn') <- zonkCoFn env co_fn ; (env'', pat') <- zonkPat env' (noLoc pat) ; ty' <- zonkTcTypeToType env'' ty ; return (env'', CoPat co_fn' (unLoc pat') ty') } zonk_pat _ pat = pprPanic "zonk_pat" (ppr pat) --------------------------- zonkConStuff :: ZonkEnv -> HsConDetails (OutPat TcId) (HsRecFields id (OutPat TcId)) -> TcM (ZonkEnv, HsConDetails (OutPat Id) (HsRecFields id (OutPat Id))) zonkConStuff env (PrefixCon pats) = do { (env', pats') <- zonkPats env pats ; return (env', PrefixCon pats') } zonkConStuff env (InfixCon p1 p2) = do { (env1, p1') <- zonkPat env p1 ; (env', p2') <- zonkPat env1 p2 ; return (env', InfixCon p1' p2') } zonkConStuff env (RecCon (HsRecFields rpats dd)) = do { (env', pats') <- zonkPats env (map (hsRecFieldArg . unLoc) rpats) ; let rpats' = zipWith (\(L l rp) p' -> L l (rp { hsRecFieldArg = p' })) rpats pats' ; return (env', RecCon (HsRecFields rpats' dd)) } -- Field selectors have declared types; hence no zonking --------------------------- zonkPats :: ZonkEnv -> [OutPat TcId] -> TcM (ZonkEnv, [OutPat Id]) zonkPats env [] = return (env, []) zonkPats env (pat:pats) = do { (env1, pat') <- zonkPat env pat ; (env', pats') <- zonkPats env1 pats ; return (env', pat':pats') } {- ************************************************************************ * * \subsection[BackSubst-Foreign]{Foreign exports} * * ************************************************************************ -} zonkForeignExports :: ZonkEnv -> [LForeignDecl TcId] -> TcM [LForeignDecl Id] zonkForeignExports env ls = mapM (wrapLocM (zonkForeignExport env)) ls zonkForeignExport :: ZonkEnv -> ForeignDecl TcId -> TcM (ForeignDecl Id) zonkForeignExport env (ForeignExport i _hs_ty co spec) = return (ForeignExport (fmap (zonkIdOcc env) i) undefined co spec) zonkForeignExport _ for_imp = return for_imp -- Foreign imports don't need zonking zonkRules :: ZonkEnv -> [LRuleDecl TcId] -> TcM [LRuleDecl Id] zonkRules env rs = mapM (wrapLocM (zonkRule env)) rs zonkRule :: ZonkEnv -> RuleDecl TcId -> TcM (RuleDecl Id) zonkRule env (HsRule name act (vars{-::[RuleBndr TcId]-}) lhs fv_lhs rhs fv_rhs) = do { unbound_tkv_set <- newMutVar emptyVarSet ; let env_rule = setZonkType env (zonkTvCollecting unbound_tkv_set) -- See Note [Zonking the LHS of a RULE] ; (env_inside, new_bndrs) <- mapAccumLM zonk_bndr env_rule vars ; new_lhs <- zonkLExpr env_inside lhs ; new_rhs <- zonkLExpr env_inside rhs ; unbound_tkvs <- readMutVar unbound_tkv_set ; let final_bndrs :: [LRuleBndr Var] final_bndrs = map (noLoc . RuleBndr . noLoc) (varSetElemsKvsFirst unbound_tkvs) ++ new_bndrs ; return $ HsRule name act final_bndrs new_lhs fv_lhs new_rhs fv_rhs } where zonk_bndr env (L l (RuleBndr (L loc v))) = do { (env', v') <- zonk_it env v ; return (env', L l (RuleBndr (L loc v'))) } zonk_bndr _ (L _ (RuleBndrSig {})) = panic "zonk_bndr RuleBndrSig" zonk_it env v | isId v = do { v' <- zonkIdBndr env v ; return (extendIdZonkEnv1 env v', v') } | otherwise = ASSERT( isImmutableTyVar v) zonkTyBndrX env v -- DV: used to be return (env,v) but that is plain -- wrong because we may need to go inside the kind -- of v and zonk there! zonkVects :: ZonkEnv -> [LVectDecl TcId] -> TcM [LVectDecl Id] zonkVects env = mapM (wrapLocM (zonkVect env)) zonkVect :: ZonkEnv -> VectDecl TcId -> TcM (VectDecl Id) zonkVect env (HsVect s v e) = do { v' <- wrapLocM (zonkIdBndr env) v ; e' <- zonkLExpr env e ; return $ HsVect s v' e' } zonkVect env (HsNoVect s v) = do { v' <- wrapLocM (zonkIdBndr env) v ; return $ HsNoVect s v' } zonkVect _env (HsVectTypeOut s t rt) = return $ HsVectTypeOut s t rt zonkVect _ (HsVectTypeIn _ _ _ _) = panic "TcHsSyn.zonkVect: HsVectTypeIn" zonkVect _env (HsVectClassOut c) = return $ HsVectClassOut c zonkVect _ (HsVectClassIn _ _) = panic "TcHsSyn.zonkVect: HsVectClassIn" zonkVect _env (HsVectInstOut i) = return $ HsVectInstOut i zonkVect _ (HsVectInstIn _) = panic "TcHsSyn.zonkVect: HsVectInstIn" {- ************************************************************************ * * Constraints and evidence * * ************************************************************************ -} zonkEvTerm :: ZonkEnv -> EvTerm -> TcM EvTerm zonkEvTerm env (EvId v) = ASSERT2( isId v, ppr v ) return (EvId (zonkIdOcc env v)) zonkEvTerm env (EvCoercion co) = do { co' <- zonkTcCoToCo env co ; return (EvCoercion co') } zonkEvTerm env (EvCast tm co) = do { tm' <- zonkEvTerm env tm ; co' <- zonkTcCoToCo env co ; return (mkEvCast tm' co') } zonkEvTerm _ (EvLit l) = return (EvLit l) zonkEvTerm env (EvTypeable ty ev) = do { ev' <- zonkEvTypeable env ev ; ty' <- zonkTcTypeToType env ty ; return (EvTypeable ty' ev') } zonkEvTerm env (EvCallStack cs) = case cs of EvCsEmpty -> return (EvCallStack cs) EvCsTop n l tm -> do { tm' <- zonkEvTerm env tm ; return (EvCallStack (EvCsTop n l tm')) } EvCsPushCall n l tm -> do { tm' <- zonkEvTerm env tm ; return (EvCallStack (EvCsPushCall n l tm')) } zonkEvTerm env (EvSuperClass d n) = do { d' <- zonkEvTerm env d ; return (EvSuperClass d' n) } zonkEvTerm env (EvDFunApp df tys tms) = do { tys' <- zonkTcTypeToTypes env tys ; return (EvDFunApp (zonkIdOcc env df) tys' (zonkIdOccs env tms)) } zonkEvTerm env (EvDelayedError ty msg) = do { ty' <- zonkTcTypeToType env ty ; return (EvDelayedError ty' msg) } zonkEvTypeable :: ZonkEnv -> EvTypeable -> TcM EvTypeable zonkEvTypeable _ EvTypeableTyCon = return EvTypeableTyCon zonkEvTypeable env (EvTypeableTyApp t1 t2) = do { t1' <- zonkEvTerm env t1 ; t2' <- zonkEvTerm env t2 ; return (EvTypeableTyApp t1' t2') } zonkEvTypeable _ (EvTypeableTyLit t1) = return (EvTypeableTyLit t1) zonkTcEvBinds_s :: ZonkEnv -> [TcEvBinds] -> TcM (ZonkEnv, [TcEvBinds]) zonkTcEvBinds_s env bs = do { (env, bs') <- mapAccumLM zonk_tc_ev_binds env bs ; return (env, [EvBinds (unionManyBags bs')]) } zonkTcEvBinds :: ZonkEnv -> TcEvBinds -> TcM (ZonkEnv, TcEvBinds) zonkTcEvBinds env bs = do { (env', bs') <- zonk_tc_ev_binds env bs ; return (env', EvBinds bs') } zonk_tc_ev_binds :: ZonkEnv -> TcEvBinds -> TcM (ZonkEnv, Bag EvBind) zonk_tc_ev_binds env (TcEvBinds var) = zonkEvBindsVar env var zonk_tc_ev_binds env (EvBinds bs) = zonkEvBinds env bs zonkEvBindsVar :: ZonkEnv -> EvBindsVar -> TcM (ZonkEnv, Bag EvBind) zonkEvBindsVar env (EvBindsVar ref _) = do { bs <- readMutVar ref ; zonkEvBinds env (evBindMapBinds bs) } zonkEvBinds :: ZonkEnv -> Bag EvBind -> TcM (ZonkEnv, Bag EvBind) zonkEvBinds env binds = {-# SCC "zonkEvBinds" #-} fixM (\ ~( _, new_binds) -> do { let env1 = extendIdZonkEnv env (collect_ev_bndrs new_binds) ; binds' <- mapBagM (zonkEvBind env1) binds ; return (env1, binds') }) where collect_ev_bndrs :: Bag EvBind -> [EvVar] collect_ev_bndrs = foldrBag add [] add (EvBind { eb_lhs = var }) vars = var : vars zonkEvBind :: ZonkEnv -> EvBind -> TcM EvBind zonkEvBind env (EvBind { eb_lhs = var, eb_rhs = term, eb_is_given = is_given }) = do { var' <- {-# SCC "zonkEvBndr" #-} zonkEvBndr env var -- Optimise the common case of Refl coercions -- See Note [Optimise coercion zonking] -- This has a very big effect on some programs (eg Trac #5030) ; term' <- case getEqPredTys_maybe (idType var') of Just (r, ty1, ty2) | ty1 `eqType` ty2 -> return (EvCoercion (mkTcReflCo r ty1)) _other -> zonkEvTerm env term ; return (EvBind { eb_lhs = var', eb_rhs = term', eb_is_given = is_given }) } {- ************************************************************************ * * Zonking types * * ************************************************************************ Note [Zonking the LHS of a RULE] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ We need to gather the type variables mentioned on the LHS so we can quantify over them. Example: data T a = C foo :: T a -> Int foo C = 1 {-# RULES "myrule" foo C = 1 #-} After type checking the LHS becomes (foo a (C a)) and we do not want to zap the unbound tyvar 'a' to (), because that limits the applicability of the rule. Instead, we want to quantify over it! It's easiest to get zonkTvCollecting to gather the free tyvars here. Attempts to do so earlier are tiresome, because (a) the data type is big and (b) finding the free type vars of an expression is necessarily monadic operation. (consider /\a -> f @ b, where b is side-effected to a) And that in turn is why ZonkEnv carries the function to use for type variables! Note [Zonking mutable unbound type or kind variables] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ In zonkTypeZapping, we zonk mutable but unbound type or kind variables to an arbitrary type. We know if they are unbound even though we don't carry an environment, because at the binding site for a variable we bind the mutable var to a fresh immutable one. So the mutable store plays the role of an environment. If we come across a mutable variable that isn't so bound, it must be completely free. We zonk the expected kind to make sure we don't get some unbound meta variable as the kind. Note that since we have kind polymorphism, zonk_unbound_tyvar will handle both type and kind variables. Consider the following datatype: data Phantom a = Phantom Int The type of Phantom is (forall (k : BOX). forall (a : k). Int). Both `a` and `k` are unbound variables. We want to zonk this to (forall (k : AnyK). forall (a : Any AnyK). Int). For that we have to check if we have a type or a kind variable; for kind variables we just return AnyK (and not the ill-kinded Any BOX). Note [Optimise coercion zonkind] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ When optimising evidence binds we may come across situations where a coercion looks like cv = ReflCo ty or cv1 = cv2 where the type 'ty' is big. In such cases it is a waste of time to zonk both * The variable on the LHS * The coercion on the RHS Rather, we can zonk the variable, and if its type is (ty ~ ty), we can just use Refl on the right, ignoring the actual coercion on the RHS. This can have a very big effect, because the constraint solver sometimes does go to a lot of effort to prove Refl! (Eg when solving 10+3 = 10+3; cf Trac #5030) -} zonkTyVarOcc :: ZonkEnv -> TyVar -> TcM TcType zonkTyVarOcc env@(ZonkEnv zonk_unbound_tyvar tv_env _) tv | isTcTyVar tv = case tcTyVarDetails tv of SkolemTv {} -> lookup_in_env RuntimeUnk {} -> lookup_in_env FlatSkol ty -> zonkTcTypeToType env ty MetaTv { mtv_ref = ref } -> do { cts <- readMutVar ref ; case cts of Flexi -> do { kind <- {-# SCC "zonkKind1" #-} zonkTcTypeToType env (tyVarKind tv) ; zonk_unbound_tyvar (setTyVarKind tv kind) } Indirect ty -> do { zty <- zonkTcTypeToType env ty -- Small optimisation: shortern-out indirect steps -- so that the old type may be more easily collected. ; writeMutVar ref (Indirect zty) ; return zty } } | otherwise = lookup_in_env where lookup_in_env -- Look up in the env just as we do for Ids = case lookupVarEnv tv_env tv of Nothing -> return (mkTyVarTy tv) Just tv' -> return (mkTyVarTy tv') zonkTcTypeToType :: ZonkEnv -> TcType -> TcM Type zonkTcTypeToType env ty = go ty where go (TyConApp tc tys) = do tys' <- mapM go tys return (mkTyConApp tc tys') -- Establish Type invariants -- See Note [Zonking inside the knot] in TcHsType go (LitTy n) = return (LitTy n) go (FunTy arg res) = do arg' <- go arg res' <- go res return (FunTy arg' res') go (AppTy fun arg) = do fun' <- go fun arg' <- go arg return (mkAppTy fun' arg') -- NB the mkAppTy; we might have instantiated a -- type variable to a type constructor, so we need -- to pull the TyConApp to the top. -- The two interesting cases! go (TyVarTy tv) = zonkTyVarOcc env tv go (ForAllTy tv ty) = ASSERT( isImmutableTyVar tv ) do { (env', tv') <- zonkTyBndrX env tv ; ty' <- zonkTcTypeToType env' ty ; return (ForAllTy tv' ty') } zonkTcTypeToTypes :: ZonkEnv -> [TcType] -> TcM [Type] zonkTcTypeToTypes env tys = mapM (zonkTcTypeToType env) tys zonkCoToCo :: ZonkEnv -> Coercion -> TcM Coercion zonkCoToCo env co = go co where go (Refl r ty) = mkReflCo r <$> zonkTcTypeToType env ty go (TyConAppCo r tc args) = mkTyConAppCo r tc <$> mapM go args go (AppCo co arg) = mkAppCo <$> go co <*> go arg go (AxiomInstCo ax ind args) = AxiomInstCo ax ind <$> mapM go args go (UnivCo s r ty1 ty2) = mkUnivCo s r <$> zonkTcTypeToType env ty1 <*> zonkTcTypeToType env ty2 go (SymCo co) = mkSymCo <$> go co go (TransCo co1 co2) = mkTransCo <$> go co1 <*> go co2 go (NthCo n co) = mkNthCo n <$> go co go (LRCo lr co) = mkLRCo lr <$> go co go (InstCo co arg) = mkInstCo <$> go co <*> zonkTcTypeToType env arg go (SubCo co) = mkSubCo <$> go co go (AxiomRuleCo ax ts cs) = AxiomRuleCo ax <$> mapM (zonkTcTypeToType env) ts <*> mapM go cs -- The two interesting cases! go (CoVarCo cv) = return (mkCoVarCo $ zonkIdOcc env cv) go (ForAllCo tv co) = ASSERT( isImmutableTyVar tv ) do { (env', tv') <- zonkTyBndrX env tv ; co' <- zonkCoToCo env' co ; return (mkForAllCo tv' co') } zonkTvCollecting :: TcRef TyVarSet -> UnboundTyVarZonker -- This variant collects unbound type variables in a mutable variable -- Works on both types and kinds zonkTvCollecting unbound_tv_set tv = do { poly_kinds <- xoptM Opt_PolyKinds ; if isKindVar tv && not poly_kinds then defaultKindVarToStar tv else do { tv' <- zonkQuantifiedTyVar tv ; tv_set <- readMutVar unbound_tv_set ; writeMutVar unbound_tv_set (extendVarSet tv_set tv') ; return (mkTyVarTy tv') } } zonkTypeZapping :: UnboundTyVarZonker -- This variant is used for everything except the LHS of rules -- It zaps unbound type variables to (), or some other arbitrary type -- Works on both types and kinds zonkTypeZapping tv = do { let ty = if isKindVar tv -- ty is actually a kind, zonk to AnyK then anyKind else anyTypeOfKind (defaultKind (tyVarKind tv)) ; writeMetaTyVar tv ty ; return ty } zonkTcCoToCo :: ZonkEnv -> TcCoercion -> TcM TcCoercion -- NB: zonking often reveals that the coercion is an identity -- in which case the Refl-ness can propagate up to the top -- which in turn gives more efficient desugaring. So it's -- worth using the 'mk' smart constructors on the RHS zonkTcCoToCo env co = go co where go (TcLetCo bs co) = do { (env', bs') <- zonkTcEvBinds env bs ; co' <- zonkTcCoToCo env' co ; return (TcLetCo bs' co') } go (TcCoVarCo cv) = return (mkTcCoVarCo (zonkEvVarOcc env cv)) go (TcRefl r ty) = do { ty' <- zonkTcTypeToType env ty ; return (TcRefl r ty') } go (TcTyConAppCo r tc cos) = do { cos' <- mapM go cos; return (mkTcTyConAppCo r tc cos') } go (TcAxiomInstCo ax ind cos) = do { cos' <- mapM go cos; return (TcAxiomInstCo ax ind cos') } go (TcAppCo co1 co2) = do { co1' <- go co1; co2' <- go co2 ; return (mkTcAppCo co1' co2') } go (TcCastCo co1 co2) = do { co1' <- go co1; co2' <- go co2 ; return (TcCastCo co1' co2') } go (TcPhantomCo ty1 ty2) = do { ty1' <- zonkTcTypeToType env ty1 ; ty2' <- zonkTcTypeToType env ty2 ; return (TcPhantomCo ty1' ty2') } go (TcSymCo co) = do { co' <- go co; return (mkTcSymCo co') } go (TcNthCo n co) = do { co' <- go co; return (mkTcNthCo n co') } go (TcLRCo lr co) = do { co' <- go co; return (mkTcLRCo lr co') } go (TcTransCo co1 co2) = do { co1' <- go co1; co2' <- go co2 ; return (mkTcTransCo co1' co2') } go (TcForAllCo tv co) = ASSERT( isImmutableTyVar tv ) do { co' <- go co; return (mkTcForAllCo tv co') } go (TcSubCo co) = do { co' <- go co; return (mkTcSubCo co') } go (TcAxiomRuleCo co ts cs) = do { ts' <- zonkTcTypeToTypes env ts ; cs' <- mapM go cs ; return (TcAxiomRuleCo co ts' cs') } go (TcCoercion co) = do { co' <- zonkCoToCo env co ; return (TcCoercion co') }