{-# LANGUAGE CPP, TypeFamilies #-} {-# LANGUAGE FlexibleContexts #-} {-# LANGUAGE ViewPatterns #-} ----------------------------------------------------------------------------- -- -- (c) The University of Glasgow 2006 -- -- The purpose of this module is to transform an HsExpr into a CoreExpr which -- when evaluated, returns a (Meta.Q Meta.Exp) computation analogous to the -- input HsExpr. We do this in the DsM monad, which supplies access to -- CoreExpr's of the "smart constructors" of the Meta.Exp datatype. -- -- It also defines a bunch of knownKeyNames, in the same way as is done -- in prelude/PrelNames. It's much more convenient to do it here, because -- otherwise we have to recompile PrelNames whenever we add a Name, which is -- a Royal Pain (triggers other recompilation). ----------------------------------------------------------------------------- module DsMeta( dsBracket ) where #include "HsVersions.h" import GhcPrelude import {-# SOURCE #-} DsExpr ( dsExpr ) import MatchLit import DsMonad import qualified Language.Haskell.TH as TH import GHC.Hs import PrelNames -- To avoid clashes with DsMeta.varName we must make a local alias for -- OccName.varName we do this by removing varName from the import of -- OccName above, making a qualified instance of OccName and using -- OccNameAlias.varName where varName ws previously used in this file. import qualified OccName( isDataOcc, isVarOcc, isTcOcc ) import Module import Id import Name hiding( isVarOcc, isTcOcc, varName, tcName ) import THNames import NameEnv import TcType import TyCon import TysWiredIn import CoreSyn import MkCore import CoreUtils import SrcLoc import Unique import BasicTypes import Outputable import Bag import DynFlags import FastString import ForeignCall import Util import Maybes import MonadUtils import Data.ByteString ( unpack ) import Control.Monad import Data.List ----------------------------------------------------------------------------- dsBracket :: HsBracket GhcRn -> [PendingTcSplice] -> DsM CoreExpr -- Returns a CoreExpr of type TH.ExpQ -- The quoted thing is parameterised over Name, even though it has -- been type checked. We don't want all those type decorations! dsBracket brack splices = dsExtendMetaEnv new_bit (do_brack brack) where new_bit = mkNameEnv [(n, DsSplice (unLoc e)) | PendingTcSplice n e <- splices] do_brack (VarBr _ _ n) = do { MkC e1 <- lookupOcc n ; return e1 } do_brack (ExpBr _ e) = do { MkC e1 <- repLE e ; return e1 } do_brack (PatBr _ p) = do { MkC p1 <- repTopP p ; return p1 } do_brack (TypBr _ t) = do { MkC t1 <- repLTy t ; return t1 } do_brack (DecBrG _ gp) = do { MkC ds1 <- repTopDs gp ; return ds1 } do_brack (DecBrL {}) = panic "dsBracket: unexpected DecBrL" do_brack (TExpBr _ e) = do { MkC e1 <- repLE e ; return e1 } do_brack (XBracket nec) = noExtCon nec {- -------------- Examples -------------------- [| \x -> x |] ====> gensym (unpackString "x"#) `bindQ` \ x1::String -> lam (pvar x1) (var x1) [| \x -> $(f [| x |]) |] ====> gensym (unpackString "x"#) `bindQ` \ x1::String -> lam (pvar x1) (f (var x1)) -} ------------------------------------------------------- -- Declarations ------------------------------------------------------- repTopP :: LPat GhcRn -> DsM (Core TH.PatQ) repTopP pat = do { ss <- mkGenSyms (collectPatBinders pat) ; pat' <- addBinds ss (repLP pat) ; wrapGenSyms ss pat' } repTopDs :: HsGroup GhcRn -> DsM (Core (TH.Q [TH.Dec])) repTopDs group@(HsGroup { hs_valds = valds , hs_splcds = splcds , hs_tyclds = tyclds , hs_derivds = derivds , hs_fixds = fixds , hs_defds = defds , hs_fords = fords , hs_warnds = warnds , hs_annds = annds , hs_ruleds = ruleds , hs_docs = docs }) = do { let { bndrs = hsScopedTvBinders valds ++ hsGroupBinders group ++ hsPatSynSelectors valds ; instds = tyclds >>= group_instds } ; ss <- mkGenSyms bndrs ; -- Bind all the names mainly to avoid repeated use of explicit strings. -- Thus we get -- do { t :: String <- genSym "T" ; -- return (Data t [] ...more t's... } -- The other important reason is that the output must mention -- only "T", not "Foo:T" where Foo is the current module decls <- addBinds ss ( do { val_ds <- rep_val_binds valds ; _ <- mapM no_splice splcds ; tycl_ds <- mapM repTyClD (tyClGroupTyClDecls tyclds) ; role_ds <- mapM repRoleD (concatMap group_roles tyclds) ; kisig_ds <- mapM repKiSigD (concatMap group_kisigs tyclds) ; inst_ds <- mapM repInstD instds ; deriv_ds <- mapM repStandaloneDerivD derivds ; fix_ds <- mapM repFixD fixds ; _ <- mapM no_default_decl defds ; for_ds <- mapM repForD fords ; _ <- mapM no_warn (concatMap (wd_warnings . unLoc) warnds) ; ann_ds <- mapM repAnnD annds ; rule_ds <- mapM repRuleD (concatMap (rds_rules . unLoc) ruleds) ; _ <- mapM no_doc docs -- more needed ; return (de_loc $ sort_by_loc $ val_ds ++ catMaybes tycl_ds ++ role_ds ++ kisig_ds ++ (concat fix_ds) ++ inst_ds ++ rule_ds ++ for_ds ++ ann_ds ++ deriv_ds) }) ; decl_ty <- lookupType decQTyConName ; let { core_list = coreList' decl_ty decls } ; dec_ty <- lookupType decTyConName ; q_decs <- repSequenceQ dec_ty core_list ; wrapGenSyms ss q_decs } where no_splice (dL->L loc _) = notHandledL loc "Splices within declaration brackets" empty no_default_decl (dL->L loc decl) = notHandledL loc "Default declarations" (ppr decl) no_warn (dL->L loc (Warning _ thing _)) = notHandledL loc "WARNING and DEPRECATION pragmas" $ text "Pragma for declaration of" <+> ppr thing no_warn _ = panic "repTopDs" no_doc (dL->L loc _) = notHandledL loc "Haddock documentation" empty repTopDs (XHsGroup nec) = noExtCon nec hsScopedTvBinders :: HsValBinds GhcRn -> [Name] -- See Note [Scoped type variables in bindings] hsScopedTvBinders binds = concatMap get_scoped_tvs sigs where sigs = case binds of ValBinds _ _ sigs -> sigs XValBindsLR (NValBinds _ sigs) -> sigs get_scoped_tvs :: LSig GhcRn -> [Name] get_scoped_tvs (dL->L _ signature) | TypeSig _ _ sig <- signature = get_scoped_tvs_from_sig (hswc_body sig) | ClassOpSig _ _ _ sig <- signature = get_scoped_tvs_from_sig sig | PatSynSig _ _ sig <- signature = get_scoped_tvs_from_sig sig | otherwise = [] where get_scoped_tvs_from_sig sig -- Both implicit and explicit quantified variables -- We need the implicit ones for f :: forall (a::k). blah -- here 'k' scopes too | HsIB { hsib_ext = implicit_vars , hsib_body = hs_ty } <- sig , (explicit_vars, _) <- splitLHsForAllTyInvis hs_ty = implicit_vars ++ hsLTyVarNames explicit_vars get_scoped_tvs_from_sig (XHsImplicitBndrs nec) = noExtCon nec {- Notes Note [Scoped type variables in bindings] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Consider f :: forall a. a -> a f x = x::a Here the 'forall a' brings 'a' into scope over the binding group. To achieve this we a) Gensym a binding for 'a' at the same time as we do one for 'f' collecting the relevant binders with hsScopedTvBinders b) When processing the 'forall', don't gensym The relevant places are signposted with references to this Note Note [Scoped type variables in class and instance declarations] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Scoped type variables may occur in default methods and default signatures. We need to bring the type variables in 'foralls' into the scope of the method bindings. Consider class Foo a where foo :: forall (b :: k). a -> Proxy b -> Proxy b foo _ x = (x :: Proxy b) We want to ensure that the 'b' in the type signature and the default implementation are the same, so we do the following: a) Before desugaring the signature and binding of 'foo', use get_scoped_tvs to collect type variables in 'forall' and create symbols for them. b) Use 'addBinds' to bring these symbols into the scope of the type signatures and bindings. c) Use these symbols to generate Core for the class/instance declaration. Note that when desugaring the signatures, we lookup the type variables from the scope rather than recreate symbols for them. See more details in "rep_ty_sig" and in Trac#14885. Note [Binders and occurrences] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ When we desugar [d| data T = MkT |] we want to get Data "T" [] [Con "MkT" []] [] and *not* Data "Foo:T" [] [Con "Foo:MkT" []] [] That is, the new data decl should fit into whatever new module it is asked to fit in. We do *not* clone, though; no need for this: Data "T79" .... But if we see this: data T = MkT foo = reifyDecl T then we must desugar to foo = Data "Foo:T" [] [Con "Foo:MkT" []] [] So in repTopDs we bring the binders into scope with mkGenSyms and addBinds. And we use lookupOcc, rather than lookupBinder in repTyClD and repC. Note [Don't quantify implicit type variables in quotes] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ If you're not careful, it's suprisingly easy to take this quoted declaration: [d| idProxy :: forall proxy (b :: k). proxy b -> proxy b idProxy x = x |] and have Template Haskell turn it into this: idProxy :: forall k proxy (b :: k). proxy b -> proxy b idProxy x = x Notice that we explicitly quantified the variable `k`! The latter declaration isn't what the user wrote in the first place. Usually, the culprit behind these bugs is taking implicitly quantified type variables (often from the hsib_vars field of HsImplicitBinders) and putting them into a `ForallT` or `ForallC`. Doing so caused #13018 and #13123. -} -- represent associated family instances -- repTyClD :: LTyClDecl GhcRn -> DsM (Maybe (SrcSpan, Core TH.DecQ)) repTyClD (dL->L loc (FamDecl { tcdFam = fam })) = liftM Just $ repFamilyDecl (L loc fam) repTyClD (dL->L loc (SynDecl { tcdLName = tc, tcdTyVars = tvs, tcdRhs = rhs })) = do { tc1 <- lookupLOcc tc -- See note [Binders and occurrences] ; dec <- addTyClTyVarBinds tvs $ \bndrs -> repSynDecl tc1 bndrs rhs ; return (Just (loc, dec)) } repTyClD (dL->L loc (DataDecl { tcdLName = tc , tcdTyVars = tvs , tcdDataDefn = defn })) = do { tc1 <- lookupLOcc tc -- See note [Binders and occurrences] ; dec <- addTyClTyVarBinds tvs $ \bndrs -> repDataDefn tc1 (Left bndrs) defn ; return (Just (loc, dec)) } repTyClD (dL->L loc (ClassDecl { tcdCtxt = cxt, tcdLName = cls, tcdTyVars = tvs, tcdFDs = fds, tcdSigs = sigs, tcdMeths = meth_binds, tcdATs = ats, tcdATDefs = atds })) = do { cls1 <- lookupLOcc cls -- See note [Binders and occurrences] ; dec <- addTyVarBinds tvs $ \bndrs -> do { cxt1 <- repLContext cxt -- See Note [Scoped type variables in class and instance declarations] ; (ss, sigs_binds) <- rep_sigs_binds sigs meth_binds ; fds1 <- repLFunDeps fds ; ats1 <- repFamilyDecls ats ; atds1 <- mapM (repAssocTyFamDefaultD . unLoc) atds ; decls1 <- coreList decQTyConName (ats1 ++ atds1 ++ sigs_binds) ; decls2 <- repClass cxt1 cls1 bndrs fds1 decls1 ; wrapGenSyms ss decls2 } ; return $ Just (loc, dec) } repTyClD _ = panic "repTyClD" ------------------------- repRoleD :: LRoleAnnotDecl GhcRn -> DsM (SrcSpan, Core TH.DecQ) repRoleD (dL->L loc (RoleAnnotDecl _ tycon roles)) = do { tycon1 <- lookupLOcc tycon ; roles1 <- mapM repRole roles ; roles2 <- coreList roleTyConName roles1 ; dec <- repRoleAnnotD tycon1 roles2 ; return (loc, dec) } repRoleD _ = panic "repRoleD" ------------------------- repKiSigD :: LStandaloneKindSig GhcRn -> DsM (SrcSpan, Core TH.DecQ) repKiSigD (dL->L loc kisig) = case kisig of StandaloneKindSig _ v ki -> rep_ty_sig kiSigDName loc ki v XStandaloneKindSig nec -> noExtCon nec ------------------------- repDataDefn :: Core TH.Name -> Either (Core [TH.TyVarBndrQ]) -- the repTyClD case (Core (Maybe [TH.TyVarBndrQ]), Core TH.TypeQ) -- the repDataFamInstD case -> HsDataDefn GhcRn -> DsM (Core TH.DecQ) repDataDefn tc opts (HsDataDefn { dd_ND = new_or_data, dd_ctxt = cxt, dd_kindSig = ksig , dd_cons = cons, dd_derivs = mb_derivs }) = do { cxt1 <- repLContext cxt ; derivs1 <- repDerivs mb_derivs ; case (new_or_data, cons) of (NewType, [con]) -> do { con' <- repC con ; ksig' <- repMaybeLTy ksig ; repNewtype cxt1 tc opts ksig' con' derivs1 } (NewType, _) -> failWithDs (text "Multiple constructors for newtype:" <+> pprQuotedList (getConNames $ unLoc $ head cons)) (DataType, _) -> do { ksig' <- repMaybeLTy ksig ; consL <- mapM repC cons ; cons1 <- coreList conQTyConName consL ; repData cxt1 tc opts ksig' cons1 derivs1 } } repDataDefn _ _ (XHsDataDefn nec) = noExtCon nec repSynDecl :: Core TH.Name -> Core [TH.TyVarBndrQ] -> LHsType GhcRn -> DsM (Core TH.DecQ) repSynDecl tc bndrs ty = do { ty1 <- repLTy ty ; repTySyn tc bndrs ty1 } repFamilyDecl :: LFamilyDecl GhcRn -> DsM (SrcSpan, Core TH.DecQ) repFamilyDecl decl@(dL->L loc (FamilyDecl { fdInfo = info , fdLName = tc , fdTyVars = tvs , fdResultSig = dL->L _ resultSig , fdInjectivityAnn = injectivity })) = do { tc1 <- lookupLOcc tc -- See note [Binders and occurrences] ; let mkHsQTvs :: [LHsTyVarBndr GhcRn] -> LHsQTyVars GhcRn mkHsQTvs tvs = HsQTvs { hsq_ext = [] , hsq_explicit = tvs } resTyVar = case resultSig of TyVarSig _ bndr -> mkHsQTvs [bndr] _ -> mkHsQTvs [] ; dec <- addTyClTyVarBinds tvs $ \bndrs -> addTyClTyVarBinds resTyVar $ \_ -> case info of ClosedTypeFamily Nothing -> notHandled "abstract closed type family" (ppr decl) ClosedTypeFamily (Just eqns) -> do { eqns1 <- mapM (repTyFamEqn . unLoc) eqns ; eqns2 <- coreList tySynEqnQTyConName eqns1 ; result <- repFamilyResultSig resultSig ; inj <- repInjectivityAnn injectivity ; repClosedFamilyD tc1 bndrs result inj eqns2 } OpenTypeFamily -> do { result <- repFamilyResultSig resultSig ; inj <- repInjectivityAnn injectivity ; repOpenFamilyD tc1 bndrs result inj } DataFamily -> do { kind <- repFamilyResultSigToMaybeKind resultSig ; repDataFamilyD tc1 bndrs kind } ; return (loc, dec) } repFamilyDecl _ = panic "repFamilyDecl" -- | Represent result signature of a type family repFamilyResultSig :: FamilyResultSig GhcRn -> DsM (Core TH.FamilyResultSigQ) repFamilyResultSig (NoSig _) = repNoSig repFamilyResultSig (KindSig _ ki) = do { ki' <- repLTy ki ; repKindSig ki' } repFamilyResultSig (TyVarSig _ bndr) = do { bndr' <- repTyVarBndr bndr ; repTyVarSig bndr' } repFamilyResultSig (XFamilyResultSig nec) = noExtCon nec -- | Represent result signature using a Maybe Kind. Used with data families, -- where the result signature can be either missing or a kind but never a named -- result variable. repFamilyResultSigToMaybeKind :: FamilyResultSig GhcRn -> DsM (Core (Maybe TH.KindQ)) repFamilyResultSigToMaybeKind (NoSig _) = do { coreNothing kindQTyConName } repFamilyResultSigToMaybeKind (KindSig _ ki) = do { ki' <- repLTy ki ; coreJust kindQTyConName ki' } repFamilyResultSigToMaybeKind _ = panic "repFamilyResultSigToMaybeKind" -- | Represent injectivity annotation of a type family repInjectivityAnn :: Maybe (LInjectivityAnn GhcRn) -> DsM (Core (Maybe TH.InjectivityAnn)) repInjectivityAnn Nothing = do { coreNothing injAnnTyConName } repInjectivityAnn (Just (dL->L _ (InjectivityAnn lhs rhs))) = do { lhs' <- lookupBinder (unLoc lhs) ; rhs1 <- mapM (lookupBinder . unLoc) rhs ; rhs2 <- coreList nameTyConName rhs1 ; injAnn <- rep2 injectivityAnnName [unC lhs', unC rhs2] ; coreJust injAnnTyConName injAnn } repFamilyDecls :: [LFamilyDecl GhcRn] -> DsM [Core TH.DecQ] repFamilyDecls fds = liftM de_loc (mapM repFamilyDecl fds) repAssocTyFamDefaultD :: TyFamDefltDecl GhcRn -> DsM (Core TH.DecQ) repAssocTyFamDefaultD = repTyFamInstD ------------------------- -- represent fundeps -- repLFunDeps :: [LHsFunDep GhcRn] -> DsM (Core [TH.FunDep]) repLFunDeps fds = repList funDepTyConName repLFunDep fds repLFunDep :: LHsFunDep GhcRn -> DsM (Core TH.FunDep) repLFunDep (dL->L _ (xs, ys)) = do xs' <- repList nameTyConName (lookupBinder . unLoc) xs ys' <- repList nameTyConName (lookupBinder . unLoc) ys repFunDep xs' ys' -- Represent instance declarations -- repInstD :: LInstDecl GhcRn -> DsM (SrcSpan, Core TH.DecQ) repInstD (dL->L loc (TyFamInstD { tfid_inst = fi_decl })) = do { dec <- repTyFamInstD fi_decl ; return (loc, dec) } repInstD (dL->L loc (DataFamInstD { dfid_inst = fi_decl })) = do { dec <- repDataFamInstD fi_decl ; return (loc, dec) } repInstD (dL->L loc (ClsInstD { cid_inst = cls_decl })) = do { dec <- repClsInstD cls_decl ; return (loc, dec) } repInstD _ = panic "repInstD" repClsInstD :: ClsInstDecl GhcRn -> DsM (Core TH.DecQ) repClsInstD (ClsInstDecl { cid_poly_ty = ty, cid_binds = binds , cid_sigs = sigs, cid_tyfam_insts = ats , cid_datafam_insts = adts , cid_overlap_mode = overlap }) = addSimpleTyVarBinds tvs $ -- We must bring the type variables into scope, so their -- occurrences don't fail, even though the binders don't -- appear in the resulting data structure -- -- But we do NOT bring the binders of 'binds' into scope -- because they are properly regarded as occurrences -- For example, the method names should be bound to -- the selector Ids, not to fresh names (#5410) -- do { cxt1 <- repLContext cxt ; inst_ty1 <- repLTy inst_ty -- See Note [Scoped type variables in class and instance declarations] ; (ss, sigs_binds) <- rep_sigs_binds sigs binds ; ats1 <- mapM (repTyFamInstD . unLoc) ats ; adts1 <- mapM (repDataFamInstD . unLoc) adts ; decls1 <- coreList decQTyConName (ats1 ++ adts1 ++ sigs_binds) ; rOver <- repOverlap (fmap unLoc overlap) ; decls2 <- repInst rOver cxt1 inst_ty1 decls1 ; wrapGenSyms ss decls2 } where (tvs, cxt, inst_ty) = splitLHsInstDeclTy ty repClsInstD (XClsInstDecl nec) = noExtCon nec repStandaloneDerivD :: LDerivDecl GhcRn -> DsM (SrcSpan, Core TH.DecQ) repStandaloneDerivD (dL->L loc (DerivDecl { deriv_strategy = strat , deriv_type = ty })) = do { dec <- addSimpleTyVarBinds tvs $ do { cxt' <- repLContext cxt ; strat' <- repDerivStrategy strat ; inst_ty' <- repLTy inst_ty ; repDeriv strat' cxt' inst_ty' } ; return (loc, dec) } where (tvs, cxt, inst_ty) = splitLHsInstDeclTy (dropWildCards ty) repStandaloneDerivD _ = panic "repStandaloneDerivD" repTyFamInstD :: TyFamInstDecl GhcRn -> DsM (Core TH.DecQ) repTyFamInstD (TyFamInstDecl { tfid_eqn = eqn }) = do { eqn1 <- repTyFamEqn eqn ; repTySynInst eqn1 } repTyFamEqn :: TyFamInstEqn GhcRn -> DsM (Core TH.TySynEqnQ) repTyFamEqn (HsIB { hsib_ext = var_names , hsib_body = FamEqn { feqn_tycon = tc_name , feqn_bndrs = mb_bndrs , feqn_pats = tys , feqn_fixity = fixity , feqn_rhs = rhs }}) = do { tc <- lookupLOcc tc_name -- See note [Binders and occurrences] ; let hs_tvs = HsQTvs { hsq_ext = var_names , hsq_explicit = fromMaybe [] mb_bndrs } ; addTyClTyVarBinds hs_tvs $ \ _ -> do { mb_bndrs1 <- repMaybeList tyVarBndrQTyConName repTyVarBndr mb_bndrs ; tys1 <- case fixity of Prefix -> repTyArgs (repNamedTyCon tc) tys Infix -> do { (HsValArg t1: HsValArg t2: args) <- checkTys tys ; t1' <- repLTy t1 ; t2' <- repLTy t2 ; repTyArgs (repTInfix t1' tc t2') args } ; rhs1 <- repLTy rhs ; repTySynEqn mb_bndrs1 tys1 rhs1 } } where checkTys :: [LHsTypeArg GhcRn] -> DsM [LHsTypeArg GhcRn] checkTys tys@(HsValArg _:HsValArg _:_) = return tys checkTys _ = panic "repTyFamEqn:checkTys" repTyFamEqn (XHsImplicitBndrs nec) = noExtCon nec repTyFamEqn (HsIB _ (XFamEqn nec)) = noExtCon nec repTyArgs :: DsM (Core TH.TypeQ) -> [LHsTypeArg GhcRn] -> DsM (Core TH.TypeQ) repTyArgs f [] = f repTyArgs f (HsValArg ty : as) = do { f' <- f ; ty' <- repLTy ty ; repTyArgs (repTapp f' ty') as } repTyArgs f (HsTypeArg _ ki : as) = do { f' <- f ; ki' <- repLTy ki ; repTyArgs (repTappKind f' ki') as } repTyArgs f (HsArgPar _ : as) = repTyArgs f as repDataFamInstD :: DataFamInstDecl GhcRn -> DsM (Core TH.DecQ) repDataFamInstD (DataFamInstDecl { dfid_eqn = (HsIB { hsib_ext = var_names , hsib_body = FamEqn { feqn_tycon = tc_name , feqn_bndrs = mb_bndrs , feqn_pats = tys , feqn_fixity = fixity , feqn_rhs = defn }})}) = do { tc <- lookupLOcc tc_name -- See note [Binders and occurrences] ; let hs_tvs = HsQTvs { hsq_ext = var_names , hsq_explicit = fromMaybe [] mb_bndrs } ; addTyClTyVarBinds hs_tvs $ \ _ -> do { mb_bndrs1 <- repMaybeList tyVarBndrQTyConName repTyVarBndr mb_bndrs ; tys1 <- case fixity of Prefix -> repTyArgs (repNamedTyCon tc) tys Infix -> do { (HsValArg t1: HsValArg t2: args) <- checkTys tys ; t1' <- repLTy t1 ; t2' <- repLTy t2 ; repTyArgs (repTInfix t1' tc t2') args } ; repDataDefn tc (Right (mb_bndrs1, tys1)) defn } } where checkTys :: [LHsTypeArg GhcRn] -> DsM [LHsTypeArg GhcRn] checkTys tys@(HsValArg _: HsValArg _: _) = return tys checkTys _ = panic "repDataFamInstD:checkTys" repDataFamInstD (DataFamInstDecl (XHsImplicitBndrs nec)) = noExtCon nec repDataFamInstD (DataFamInstDecl (HsIB _ (XFamEqn nec))) = noExtCon nec repForD :: Located (ForeignDecl GhcRn) -> DsM (SrcSpan, Core TH.DecQ) repForD (dL->L loc (ForeignImport { fd_name = name, fd_sig_ty = typ , fd_fi = CImport (dL->L _ cc) (dL->L _ s) mch cis _ })) = do MkC name' <- lookupLOcc name MkC typ' <- repHsSigType typ MkC cc' <- repCCallConv cc MkC s' <- repSafety s cis' <- conv_cimportspec cis MkC str <- coreStringLit (static ++ chStr ++ cis') dec <- rep2 forImpDName [cc', s', str, name', typ'] return (loc, dec) where conv_cimportspec (CLabel cls) = notHandled "Foreign label" (doubleQuotes (ppr cls)) conv_cimportspec (CFunction DynamicTarget) = return "dynamic" conv_cimportspec (CFunction (StaticTarget _ fs _ True)) = return (unpackFS fs) conv_cimportspec (CFunction (StaticTarget _ _ _ False)) = panic "conv_cimportspec: values not supported yet" conv_cimportspec CWrapper = return "wrapper" -- these calling conventions do not support headers and the static keyword raw_cconv = cc == PrimCallConv || cc == JavaScriptCallConv static = case cis of CFunction (StaticTarget _ _ _ _) | not raw_cconv -> "static " _ -> "" chStr = case mch of Just (Header _ h) | not raw_cconv -> unpackFS h ++ " " _ -> "" repForD decl = notHandled "Foreign declaration" (ppr decl) repCCallConv :: CCallConv -> DsM (Core TH.Callconv) repCCallConv CCallConv = rep2 cCallName [] repCCallConv StdCallConv = rep2 stdCallName [] repCCallConv CApiConv = rep2 cApiCallName [] repCCallConv PrimCallConv = rep2 primCallName [] repCCallConv JavaScriptCallConv = rep2 javaScriptCallName [] repSafety :: Safety -> DsM (Core TH.Safety) repSafety PlayRisky = rep2 unsafeName [] repSafety PlayInterruptible = rep2 interruptibleName [] repSafety PlaySafe = rep2 safeName [] repFixD :: LFixitySig GhcRn -> DsM [(SrcSpan, Core TH.DecQ)] repFixD (dL->L loc (FixitySig _ names (Fixity _ prec dir))) = do { MkC prec' <- coreIntLit prec ; let rep_fn = case dir of InfixL -> infixLDName InfixR -> infixRDName InfixN -> infixNDName ; let do_one name = do { MkC name' <- lookupLOcc name ; dec <- rep2 rep_fn [prec', name'] ; return (loc,dec) } ; mapM do_one names } repFixD _ = panic "repFixD" repRuleD :: LRuleDecl GhcRn -> DsM (SrcSpan, Core TH.DecQ) repRuleD (dL->L loc (HsRule { rd_name = n , rd_act = act , rd_tyvs = ty_bndrs , rd_tmvs = tm_bndrs , rd_lhs = lhs , rd_rhs = rhs })) = do { rule <- addHsTyVarBinds (fromMaybe [] ty_bndrs) $ \ ex_bndrs -> do { let tm_bndr_names = concatMap ruleBndrNames tm_bndrs ; ss <- mkGenSyms tm_bndr_names ; rule <- addBinds ss $ do { ty_bndrs' <- case ty_bndrs of Nothing -> coreNothingList tyVarBndrQTyConName Just _ -> coreJustList tyVarBndrQTyConName ex_bndrs ; tm_bndrs' <- repList ruleBndrQTyConName repRuleBndr tm_bndrs ; n' <- coreStringLit $ unpackFS $ snd $ unLoc n ; act' <- repPhases act ; lhs' <- repLE lhs ; rhs' <- repLE rhs ; repPragRule n' ty_bndrs' tm_bndrs' lhs' rhs' act' } ; wrapGenSyms ss rule } ; return (loc, rule) } repRuleD _ = panic "repRuleD" ruleBndrNames :: LRuleBndr GhcRn -> [Name] ruleBndrNames (dL->L _ (RuleBndr _ n)) = [unLoc n] ruleBndrNames (dL->L _ (RuleBndrSig _ n sig)) | HsWC { hswc_body = HsIB { hsib_ext = vars }} <- sig = unLoc n : vars ruleBndrNames (dL->L _ (RuleBndrSig _ _ (HsWC _ (XHsImplicitBndrs _)))) = panic "ruleBndrNames" ruleBndrNames (dL->L _ (RuleBndrSig _ _ (XHsWildCardBndrs _))) = panic "ruleBndrNames" ruleBndrNames (dL->L _ (XRuleBndr nec)) = noExtCon nec ruleBndrNames _ = panic "ruleBndrNames: Impossible Match" -- due to #15884 repRuleBndr :: LRuleBndr GhcRn -> DsM (Core TH.RuleBndrQ) repRuleBndr (dL->L _ (RuleBndr _ n)) = do { MkC n' <- lookupLBinder n ; rep2 ruleVarName [n'] } repRuleBndr (dL->L _ (RuleBndrSig _ n sig)) = do { MkC n' <- lookupLBinder n ; MkC ty' <- repLTy (hsSigWcType sig) ; rep2 typedRuleVarName [n', ty'] } repRuleBndr _ = panic "repRuleBndr" repAnnD :: LAnnDecl GhcRn -> DsM (SrcSpan, Core TH.DecQ) repAnnD (dL->L loc (HsAnnotation _ _ ann_prov (dL->L _ exp))) = do { target <- repAnnProv ann_prov ; exp' <- repE exp ; dec <- repPragAnn target exp' ; return (loc, dec) } repAnnD _ = panic "repAnnD" repAnnProv :: AnnProvenance Name -> DsM (Core TH.AnnTarget) repAnnProv (ValueAnnProvenance (dL->L _ n)) = do { MkC n' <- globalVar n -- ANNs are allowed only at top-level ; rep2 valueAnnotationName [ n' ] } repAnnProv (TypeAnnProvenance (dL->L _ n)) = do { MkC n' <- globalVar n ; rep2 typeAnnotationName [ n' ] } repAnnProv ModuleAnnProvenance = rep2 moduleAnnotationName [] ------------------------------------------------------- -- Constructors ------------------------------------------------------- repC :: LConDecl GhcRn -> DsM (Core TH.ConQ) repC (dL->L _ (ConDeclH98 { con_name = con , con_forall = (dL->L _ False) , con_mb_cxt = Nothing , con_args = args })) = repDataCon con args repC (dL->L _ (ConDeclH98 { con_name = con , con_forall = (dL->L _ is_existential) , con_ex_tvs = con_tvs , con_mb_cxt = mcxt , con_args = args })) = do { addHsTyVarBinds con_tvs $ \ ex_bndrs -> do { c' <- repDataCon con args ; ctxt' <- repMbContext mcxt ; if not is_existential && isNothing mcxt then return c' else rep2 forallCName ([unC ex_bndrs, unC ctxt', unC c']) } } repC (dL->L _ (ConDeclGADT { con_names = cons , con_qvars = qtvs , con_mb_cxt = mcxt , con_args = args , con_res_ty = res_ty })) | isEmptyLHsQTvs qtvs -- No implicit or explicit variables , Nothing <- mcxt -- No context -- ==> no need for a forall = repGadtDataCons cons args res_ty | otherwise = addTyVarBinds qtvs $ \ ex_bndrs -> -- See Note [Don't quantify implicit type variables in quotes] do { c' <- repGadtDataCons cons args res_ty ; ctxt' <- repMbContext mcxt ; if null (hsQTvExplicit qtvs) && isNothing mcxt then return c' else rep2 forallCName ([unC ex_bndrs, unC ctxt', unC c']) } repC _ = panic "repC" repMbContext :: Maybe (LHsContext GhcRn) -> DsM (Core TH.CxtQ) repMbContext Nothing = repContext [] repMbContext (Just (dL->L _ cxt)) = repContext cxt repSrcUnpackedness :: SrcUnpackedness -> DsM (Core TH.SourceUnpackednessQ) repSrcUnpackedness SrcUnpack = rep2 sourceUnpackName [] repSrcUnpackedness SrcNoUnpack = rep2 sourceNoUnpackName [] repSrcUnpackedness NoSrcUnpack = rep2 noSourceUnpackednessName [] repSrcStrictness :: SrcStrictness -> DsM (Core TH.SourceStrictnessQ) repSrcStrictness SrcLazy = rep2 sourceLazyName [] repSrcStrictness SrcStrict = rep2 sourceStrictName [] repSrcStrictness NoSrcStrict = rep2 noSourceStrictnessName [] repBangTy :: LBangType GhcRn -> DsM (Core (TH.BangTypeQ)) repBangTy ty = do MkC u <- repSrcUnpackedness su' MkC s <- repSrcStrictness ss' MkC b <- rep2 bangName [u, s] MkC t <- repLTy ty' rep2 bangTypeName [b, t] where (su', ss', ty') = case unLoc ty of HsBangTy _ (HsSrcBang _ su ss) ty -> (su, ss, ty) _ -> (NoSrcUnpack, NoSrcStrict, ty) ------------------------------------------------------- -- Deriving clauses ------------------------------------------------------- repDerivs :: HsDeriving GhcRn -> DsM (Core [TH.DerivClauseQ]) repDerivs (dL->L _ clauses) = repList derivClauseQTyConName repDerivClause clauses repDerivClause :: LHsDerivingClause GhcRn -> DsM (Core TH.DerivClauseQ) repDerivClause (dL->L _ (HsDerivingClause { deriv_clause_strategy = dcs , deriv_clause_tys = (dL->L _ dct) })) = do MkC dcs' <- repDerivStrategy dcs MkC dct' <- repList typeQTyConName (rep_deriv_ty . hsSigType) dct rep2 derivClauseName [dcs',dct'] where rep_deriv_ty :: LHsType GhcRn -> DsM (Core TH.TypeQ) rep_deriv_ty ty = repLTy ty repDerivClause _ = panic "repDerivClause" rep_sigs_binds :: [LSig GhcRn] -> LHsBinds GhcRn -> DsM ([GenSymBind], [Core TH.DecQ]) -- Represent signatures and methods in class/instance declarations. -- See Note [Scoped type variables in class and instance declarations] -- -- Why not use 'repBinds': we have already created symbols for methods in -- 'repTopDs' via 'hsGroupBinders'. However in 'repBinds', we recreate -- these fun_id via 'collectHsValBinders decs', which would lead to the -- instance declarations failing in TH. rep_sigs_binds sigs binds = do { let tvs = concatMap get_scoped_tvs sigs ; ss <- mkGenSyms tvs ; sigs1 <- addBinds ss $ rep_sigs sigs ; binds1 <- addBinds ss $ rep_binds binds ; return (ss, de_loc (sort_by_loc (sigs1 ++ binds1))) } ------------------------------------------------------- -- Signatures in a class decl, or a group of bindings ------------------------------------------------------- rep_sigs :: [LSig GhcRn] -> DsM [(SrcSpan, Core TH.DecQ)] -- We silently ignore ones we don't recognise rep_sigs = concatMapM rep_sig rep_sig :: LSig GhcRn -> DsM [(SrcSpan, Core TH.DecQ)] rep_sig (dL->L loc (TypeSig _ nms ty)) = mapM (rep_wc_ty_sig sigDName loc ty) nms rep_sig (dL->L loc (PatSynSig _ nms ty)) = mapM (rep_patsyn_ty_sig loc ty) nms rep_sig (dL->L loc (ClassOpSig _ is_deflt nms ty)) | is_deflt = mapM (rep_ty_sig defaultSigDName loc ty) nms | otherwise = mapM (rep_ty_sig sigDName loc ty) nms rep_sig d@(dL->L _ (IdSig {})) = pprPanic "rep_sig IdSig" (ppr d) rep_sig (dL->L _ (FixSig {})) = return [] -- fixity sigs at top level rep_sig (dL->L loc (InlineSig _ nm ispec))= rep_inline nm ispec loc rep_sig (dL->L loc (SpecSig _ nm tys ispec)) = concatMapM (\t -> rep_specialise nm t ispec loc) tys rep_sig (dL->L loc (SpecInstSig _ _ ty)) = rep_specialiseInst ty loc rep_sig (dL->L _ (MinimalSig {})) = notHandled "MINIMAL pragmas" empty rep_sig (dL->L _ (SCCFunSig {})) = notHandled "SCC pragmas" empty rep_sig (dL->L loc (CompleteMatchSig _ _st cls mty)) = rep_complete_sig cls mty loc rep_sig _ = panic "rep_sig" rep_ty_sig :: Name -> SrcSpan -> LHsSigType GhcRn -> Located Name -> DsM (SrcSpan, Core TH.DecQ) -- Don't create the implicit and explicit variables when desugaring signatures, -- see Note [Scoped type variables in class and instance declarations]. -- and Note [Don't quantify implicit type variables in quotes] rep_ty_sig mk_sig loc sig_ty nm | HsIB { hsib_body = hs_ty } <- sig_ty , (explicit_tvs, ctxt, ty) <- splitLHsSigmaTyInvis hs_ty = do { nm1 <- lookupLOcc nm ; let rep_in_scope_tv tv = do { name <- lookupBinder (hsLTyVarName tv) ; repTyVarBndrWithKind tv name } ; th_explicit_tvs <- repList tyVarBndrQTyConName rep_in_scope_tv explicit_tvs -- NB: Don't pass any implicit type variables to repList above -- See Note [Don't quantify implicit type variables in quotes] ; th_ctxt <- repLContext ctxt ; th_ty <- repLTy ty ; ty1 <- if null explicit_tvs && null (unLoc ctxt) then return th_ty else repTForall th_explicit_tvs th_ctxt th_ty ; sig <- repProto mk_sig nm1 ty1 ; return (loc, sig) } rep_ty_sig _ _ (XHsImplicitBndrs nec) _ = noExtCon nec rep_patsyn_ty_sig :: SrcSpan -> LHsSigType GhcRn -> Located Name -> DsM (SrcSpan, Core TH.DecQ) -- represents a pattern synonym type signature; -- see Note [Pattern synonym type signatures and Template Haskell] in Convert -- -- Don't create the implicit and explicit variables when desugaring signatures, -- see Note [Scoped type variables in class and instance declarations] -- and Note [Don't quantify implicit type variables in quotes] rep_patsyn_ty_sig loc sig_ty nm | HsIB { hsib_body = hs_ty } <- sig_ty , (univs, reqs, exis, provs, ty) <- splitLHsPatSynTy hs_ty = do { nm1 <- lookupLOcc nm ; let rep_in_scope_tv tv = do { name <- lookupBinder (hsLTyVarName tv) ; repTyVarBndrWithKind tv name } ; th_univs <- repList tyVarBndrQTyConName rep_in_scope_tv univs ; th_exis <- repList tyVarBndrQTyConName rep_in_scope_tv exis -- NB: Don't pass any implicit type variables to repList above -- See Note [Don't quantify implicit type variables in quotes] ; th_reqs <- repLContext reqs ; th_provs <- repLContext provs ; th_ty <- repLTy ty ; ty1 <- repTForall th_univs th_reqs =<< repTForall th_exis th_provs th_ty ; sig <- repProto patSynSigDName nm1 ty1 ; return (loc, sig) } rep_patsyn_ty_sig _ (XHsImplicitBndrs nec) _ = noExtCon nec rep_wc_ty_sig :: Name -> SrcSpan -> LHsSigWcType GhcRn -> Located Name -> DsM (SrcSpan, Core TH.DecQ) rep_wc_ty_sig mk_sig loc sig_ty nm = rep_ty_sig mk_sig loc (hswc_body sig_ty) nm rep_inline :: Located Name -> InlinePragma -- Never defaultInlinePragma -> SrcSpan -> DsM [(SrcSpan, Core TH.DecQ)] rep_inline nm ispec loc = do { nm1 <- lookupLOcc nm ; inline <- repInline $ inl_inline ispec ; rm <- repRuleMatch $ inl_rule ispec ; phases <- repPhases $ inl_act ispec ; pragma <- repPragInl nm1 inline rm phases ; return [(loc, pragma)] } rep_specialise :: Located Name -> LHsSigType GhcRn -> InlinePragma -> SrcSpan -> DsM [(SrcSpan, Core TH.DecQ)] rep_specialise nm ty ispec loc = do { nm1 <- lookupLOcc nm ; ty1 <- repHsSigType ty ; phases <- repPhases $ inl_act ispec ; let inline = inl_inline ispec ; pragma <- if noUserInlineSpec inline then -- SPECIALISE repPragSpec nm1 ty1 phases else -- SPECIALISE INLINE do { inline1 <- repInline inline ; repPragSpecInl nm1 ty1 inline1 phases } ; return [(loc, pragma)] } rep_specialiseInst :: LHsSigType GhcRn -> SrcSpan -> DsM [(SrcSpan, Core TH.DecQ)] rep_specialiseInst ty loc = do { ty1 <- repHsSigType ty ; pragma <- repPragSpecInst ty1 ; return [(loc, pragma)] } repInline :: InlineSpec -> DsM (Core TH.Inline) repInline NoInline = dataCon noInlineDataConName repInline Inline = dataCon inlineDataConName repInline Inlinable = dataCon inlinableDataConName repInline spec = notHandled "repInline" (ppr spec) repRuleMatch :: RuleMatchInfo -> DsM (Core TH.RuleMatch) repRuleMatch ConLike = dataCon conLikeDataConName repRuleMatch FunLike = dataCon funLikeDataConName repPhases :: Activation -> DsM (Core TH.Phases) repPhases (ActiveBefore _ i) = do { MkC arg <- coreIntLit i ; dataCon' beforePhaseDataConName [arg] } repPhases (ActiveAfter _ i) = do { MkC arg <- coreIntLit i ; dataCon' fromPhaseDataConName [arg] } repPhases _ = dataCon allPhasesDataConName rep_complete_sig :: Located [Located Name] -> Maybe (Located Name) -> SrcSpan -> DsM [(SrcSpan, Core TH.DecQ)] rep_complete_sig (dL->L _ cls) mty loc = do { mty' <- repMaybe nameTyConName lookupLOcc mty ; cls' <- repList nameTyConName lookupLOcc cls ; sig <- repPragComplete cls' mty' ; return [(loc, sig)] } ------------------------------------------------------- -- Types ------------------------------------------------------- addSimpleTyVarBinds :: [Name] -- the binders to be added -> DsM (Core (TH.Q a)) -- action in the ext env -> DsM (Core (TH.Q a)) addSimpleTyVarBinds names thing_inside = do { fresh_names <- mkGenSyms names ; term <- addBinds fresh_names thing_inside ; wrapGenSyms fresh_names term } addHsTyVarBinds :: [LHsTyVarBndr GhcRn] -- the binders to be added -> (Core [TH.TyVarBndrQ] -> DsM (Core (TH.Q a))) -- action in the ext env -> DsM (Core (TH.Q a)) addHsTyVarBinds exp_tvs thing_inside = do { fresh_exp_names <- mkGenSyms (hsLTyVarNames exp_tvs) ; term <- addBinds fresh_exp_names $ do { kbs <- repList tyVarBndrQTyConName mk_tv_bndr (exp_tvs `zip` fresh_exp_names) ; thing_inside kbs } ; wrapGenSyms fresh_exp_names term } where mk_tv_bndr (tv, (_,v)) = repTyVarBndrWithKind tv (coreVar v) addTyVarBinds :: LHsQTyVars GhcRn -- the binders to be added -> (Core [TH.TyVarBndrQ] -> DsM (Core (TH.Q a))) -- action in the ext env -> DsM (Core (TH.Q a)) -- gensym a list of type variables and enter them into the meta environment; -- the computations passed as the second argument is executed in that extended -- meta environment and gets the *new* names on Core-level as an argument addTyVarBinds (HsQTvs { hsq_ext = imp_tvs , hsq_explicit = exp_tvs }) thing_inside = addSimpleTyVarBinds imp_tvs $ addHsTyVarBinds exp_tvs $ thing_inside addTyVarBinds (XLHsQTyVars nec) _ = noExtCon nec addTyClTyVarBinds :: LHsQTyVars GhcRn -> (Core [TH.TyVarBndrQ] -> DsM (Core (TH.Q a))) -> DsM (Core (TH.Q a)) -- Used for data/newtype declarations, and family instances, -- so that the nested type variables work right -- instance C (T a) where -- type W (T a) = blah -- The 'a' in the type instance is the one bound by the instance decl addTyClTyVarBinds tvs m = do { let tv_names = hsAllLTyVarNames tvs ; env <- dsGetMetaEnv ; freshNames <- mkGenSyms (filterOut (`elemNameEnv` env) tv_names) -- Make fresh names for the ones that are not already in scope -- This makes things work for family declarations ; term <- addBinds freshNames $ do { kbs <- repList tyVarBndrQTyConName mk_tv_bndr (hsQTvExplicit tvs) ; m kbs } ; wrapGenSyms freshNames term } where mk_tv_bndr :: LHsTyVarBndr GhcRn -> DsM (Core TH.TyVarBndrQ) mk_tv_bndr tv = do { v <- lookupBinder (hsLTyVarName tv) ; repTyVarBndrWithKind tv v } -- Produce kinded binder constructors from the Haskell tyvar binders -- repTyVarBndrWithKind :: LHsTyVarBndr GhcRn -> Core TH.Name -> DsM (Core TH.TyVarBndrQ) repTyVarBndrWithKind (dL->L _ (UserTyVar _ _)) nm = repPlainTV nm repTyVarBndrWithKind (dL->L _ (KindedTyVar _ _ ki)) nm = repLTy ki >>= repKindedTV nm repTyVarBndrWithKind _ _ = panic "repTyVarBndrWithKind" -- | Represent a type variable binder repTyVarBndr :: LHsTyVarBndr GhcRn -> DsM (Core TH.TyVarBndrQ) repTyVarBndr (dL->L _ (UserTyVar _ (dL->L _ nm)) ) = do { nm' <- lookupBinder nm ; repPlainTV nm' } repTyVarBndr (dL->L _ (KindedTyVar _ (dL->L _ nm) ki)) = do { nm' <- lookupBinder nm ; ki' <- repLTy ki ; repKindedTV nm' ki' } repTyVarBndr _ = panic "repTyVarBndr" -- represent a type context -- repLContext :: LHsContext GhcRn -> DsM (Core TH.CxtQ) repLContext ctxt = repContext (unLoc ctxt) repContext :: HsContext GhcRn -> DsM (Core TH.CxtQ) repContext ctxt = do preds <- repList typeQTyConName repLTy ctxt repCtxt preds repHsSigType :: LHsSigType GhcRn -> DsM (Core TH.TypeQ) repHsSigType (HsIB { hsib_ext = implicit_tvs , hsib_body = body }) | (explicit_tvs, ctxt, ty) <- splitLHsSigmaTyInvis body = addSimpleTyVarBinds implicit_tvs $ -- See Note [Don't quantify implicit type variables in quotes] addHsTyVarBinds explicit_tvs $ \ th_explicit_tvs -> do { th_ctxt <- repLContext ctxt ; th_ty <- repLTy ty ; if null explicit_tvs && null (unLoc ctxt) then return th_ty else repTForall th_explicit_tvs th_ctxt th_ty } repHsSigType (XHsImplicitBndrs nec) = noExtCon nec repHsSigWcType :: LHsSigWcType GhcRn -> DsM (Core TH.TypeQ) repHsSigWcType (HsWC { hswc_body = sig1 }) = repHsSigType sig1 repHsSigWcType (XHsWildCardBndrs nec) = noExtCon nec -- yield the representation of a list of types repLTys :: [LHsType GhcRn] -> DsM [Core TH.TypeQ] repLTys tys = mapM repLTy tys -- represent a type repLTy :: LHsType GhcRn -> DsM (Core TH.TypeQ) repLTy ty = repTy (unLoc ty) -- Desugar a type headed by an invisible forall (e.g., @forall a. a@) or -- a context (e.g., @Show a => a@) into a ForallT from L.H.TH.Syntax. -- In other words, the argument to this function is always an -- @HsForAllTy ForallInvis@ or @HsQualTy@. -- Types headed by visible foralls (which are desugared to ForallVisT) are -- handled separately in repTy. repForallT :: HsType GhcRn -> DsM (Core TH.TypeQ) repForallT ty | (tvs, ctxt, tau) <- splitLHsSigmaTyInvis (noLoc ty) = addHsTyVarBinds tvs $ \bndrs -> do { ctxt1 <- repLContext ctxt ; tau1 <- repLTy tau ; repTForall bndrs ctxt1 tau1 -- forall a. C a => {...} } repTy :: HsType GhcRn -> DsM (Core TH.TypeQ) repTy ty@(HsForAllTy { hst_fvf = fvf, hst_bndrs = tvs, hst_body = body }) = case fvf of ForallInvis -> repForallT ty ForallVis -> addHsTyVarBinds tvs $ \bndrs -> do body1 <- repLTy body repTForallVis bndrs body1 repTy ty@(HsQualTy {}) = repForallT ty repTy (HsTyVar _ _ (dL->L _ n)) | isLiftedTypeKindTyConName n = repTStar | n `hasKey` constraintKindTyConKey = repTConstraint | n `hasKey` funTyConKey = repArrowTyCon | isTvOcc occ = do tv1 <- lookupOcc n repTvar tv1 | isDataOcc occ = do tc1 <- lookupOcc n repPromotedDataCon tc1 | n == eqTyConName = repTequality | otherwise = do tc1 <- lookupOcc n repNamedTyCon tc1 where occ = nameOccName n repTy (HsAppTy _ f a) = do f1 <- repLTy f a1 <- repLTy a repTapp f1 a1 repTy (HsAppKindTy _ ty ki) = do ty1 <- repLTy ty ki1 <- repLTy ki repTappKind ty1 ki1 repTy (HsFunTy _ f a) = do f1 <- repLTy f a1 <- repLTy a tcon <- repArrowTyCon repTapps tcon [f1, a1] repTy (HsListTy _ t) = do t1 <- repLTy t tcon <- repListTyCon repTapp tcon t1 repTy (HsTupleTy _ HsUnboxedTuple tys) = do tys1 <- repLTys tys tcon <- repUnboxedTupleTyCon (length tys) repTapps tcon tys1 repTy (HsTupleTy _ _ tys) = do tys1 <- repLTys tys tcon <- repTupleTyCon (length tys) repTapps tcon tys1 repTy (HsSumTy _ tys) = do tys1 <- repLTys tys tcon <- repUnboxedSumTyCon (length tys) repTapps tcon tys1 repTy (HsOpTy _ ty1 n ty2) = repLTy ((nlHsTyVar (unLoc n) `nlHsAppTy` ty1) `nlHsAppTy` ty2) repTy (HsParTy _ t) = repLTy t repTy (HsStarTy _ _) = repTStar repTy (HsKindSig _ t k) = do t1 <- repLTy t k1 <- repLTy k repTSig t1 k1 repTy (HsSpliceTy _ splice) = repSplice splice repTy (HsExplicitListTy _ _ tys) = do tys1 <- repLTys tys repTPromotedList tys1 repTy (HsExplicitTupleTy _ tys) = do tys1 <- repLTys tys tcon <- repPromotedTupleTyCon (length tys) repTapps tcon tys1 repTy (HsTyLit _ lit) = do lit' <- repTyLit lit repTLit lit' repTy (HsWildCardTy _) = repTWildCard repTy (HsIParamTy _ n t) = do n' <- rep_implicit_param_name (unLoc n) t' <- repLTy t repTImplicitParam n' t' repTy ty = notHandled "Exotic form of type" (ppr ty) repTyLit :: HsTyLit -> DsM (Core TH.TyLitQ) repTyLit (HsNumTy _ i) = do iExpr <- mkIntegerExpr i rep2 numTyLitName [iExpr] repTyLit (HsStrTy _ s) = do { s' <- mkStringExprFS s ; rep2 strTyLitName [s'] } -- | Represent a type wrapped in a Maybe repMaybeLTy :: Maybe (LHsKind GhcRn) -> DsM (Core (Maybe TH.TypeQ)) repMaybeLTy = repMaybe kindQTyConName repLTy repRole :: Located (Maybe Role) -> DsM (Core TH.Role) repRole (dL->L _ (Just Nominal)) = rep2 nominalRName [] repRole (dL->L _ (Just Representational)) = rep2 representationalRName [] repRole (dL->L _ (Just Phantom)) = rep2 phantomRName [] repRole (dL->L _ Nothing) = rep2 inferRName [] repRole _ = panic "repRole: Impossible Match" -- due to #15884 ----------------------------------------------------------------------------- -- Splices ----------------------------------------------------------------------------- repSplice :: HsSplice GhcRn -> DsM (Core a) -- See Note [How brackets and nested splices are handled] in TcSplice -- We return a CoreExpr of any old type; the context should know repSplice (HsTypedSplice _ _ n _) = rep_splice n repSplice (HsUntypedSplice _ _ n _) = rep_splice n repSplice (HsQuasiQuote _ n _ _ _) = rep_splice n repSplice e@(HsSpliced {}) = pprPanic "repSplice" (ppr e) repSplice e@(HsSplicedT {}) = pprPanic "repSpliceT" (ppr e) repSplice (XSplice nec) = noExtCon nec rep_splice :: Name -> DsM (Core a) rep_splice splice_name = do { mb_val <- dsLookupMetaEnv splice_name ; case mb_val of Just (DsSplice e) -> do { e' <- dsExpr e ; return (MkC e') } _ -> pprPanic "HsSplice" (ppr splice_name) } -- Should not happen; statically checked ----------------------------------------------------------------------------- -- Expressions ----------------------------------------------------------------------------- repLEs :: [LHsExpr GhcRn] -> DsM (Core [TH.ExpQ]) repLEs es = repList expQTyConName repLE es -- FIXME: some of these panics should be converted into proper error messages -- unless we can make sure that constructs, which are plainly not -- supported in TH already lead to error messages at an earlier stage repLE :: LHsExpr GhcRn -> DsM (Core TH.ExpQ) repLE (dL->L loc e) = putSrcSpanDs loc (repE e) repE :: HsExpr GhcRn -> DsM (Core TH.ExpQ) repE (HsVar _ (dL->L _ x)) = do { mb_val <- dsLookupMetaEnv x ; case mb_val of Nothing -> do { str <- globalVar x ; repVarOrCon x str } Just (DsBound y) -> repVarOrCon x (coreVar y) Just (DsSplice e) -> do { e' <- dsExpr e ; return (MkC e') } } repE (HsIPVar _ n) = rep_implicit_param_name n >>= repImplicitParamVar repE (HsOverLabel _ _ s) = repOverLabel s repE e@(HsRecFld _ f) = case f of Unambiguous x _ -> repE (HsVar noExtField (noLoc x)) Ambiguous{} -> notHandled "Ambiguous record selectors" (ppr e) XAmbiguousFieldOcc{} -> notHandled "XAmbiguous record selectors" (ppr e) -- Remember, we're desugaring renamer output here, so -- HsOverlit can definitely occur repE (HsOverLit _ l) = do { a <- repOverloadedLiteral l; repLit a } repE (HsLit _ l) = do { a <- repLiteral l; repLit a } repE (HsLam _ (MG { mg_alts = (dL->L _ [m]) })) = repLambda m repE (HsLamCase _ (MG { mg_alts = (dL->L _ ms) })) = do { ms' <- mapM repMatchTup ms ; core_ms <- coreList matchQTyConName ms' ; repLamCase core_ms } repE (HsApp _ x y) = do {a <- repLE x; b <- repLE y; repApp a b} repE (HsAppType _ e t) = do { a <- repLE e ; s <- repLTy (hswc_body t) ; repAppType a s } repE (OpApp _ e1 op e2) = do { arg1 <- repLE e1; arg2 <- repLE e2; the_op <- repLE op ; repInfixApp arg1 the_op arg2 } repE (NegApp _ x _) = do a <- repLE x negateVar <- lookupOcc negateName >>= repVar negateVar `repApp` a repE (HsPar _ x) = repLE x repE (SectionL _ x y) = do { a <- repLE x; b <- repLE y; repSectionL a b } repE (SectionR _ x y) = do { a <- repLE x; b <- repLE y; repSectionR a b } repE (HsCase _ e (MG { mg_alts = (dL->L _ ms) })) = do { arg <- repLE e ; ms2 <- mapM repMatchTup ms ; core_ms2 <- coreList matchQTyConName ms2 ; repCaseE arg core_ms2 } repE (HsIf _ _ x y z) = do a <- repLE x b <- repLE y c <- repLE z repCond a b c repE (HsMultiIf _ alts) = do { (binds, alts') <- liftM unzip $ mapM repLGRHS alts ; expr' <- repMultiIf (nonEmptyCoreList alts') ; wrapGenSyms (concat binds) expr' } repE (HsLet _ (dL->L _ bs) e) = do { (ss,ds) <- repBinds bs ; e2 <- addBinds ss (repLE e) ; z <- repLetE ds e2 ; wrapGenSyms ss z } -- FIXME: I haven't got the types here right yet repE e@(HsDo _ ctxt (dL->L _ sts)) | case ctxt of { DoExpr -> True; GhciStmtCtxt -> True; _ -> False } = do { (ss,zs) <- repLSts sts; e' <- repDoE (nonEmptyCoreList zs); wrapGenSyms ss e' } | ListComp <- ctxt = do { (ss,zs) <- repLSts sts; e' <- repComp (nonEmptyCoreList zs); wrapGenSyms ss e' } | MDoExpr <- ctxt = do { (ss,zs) <- repLSts sts; e' <- repMDoE (nonEmptyCoreList zs); wrapGenSyms ss e' } | otherwise = notHandled "monad comprehension and [: :]" (ppr e) repE (ExplicitList _ _ es) = do { xs <- repLEs es; repListExp xs } repE (ExplicitTuple _ es boxity) = let tupArgToCoreExp :: LHsTupArg GhcRn -> DsM (Core (Maybe TH.ExpQ)) tupArgToCoreExp a | L _ (Present _ e) <- dL a = do { e' <- repLE e ; coreJust expQTyConName e' } | otherwise = coreNothing expQTyConName in do { args <- mapM tupArgToCoreExp es ; expQTy <- lookupType expQTyConName ; let maybeExpQTy = mkTyConApp maybeTyCon [expQTy] listArg = coreList' maybeExpQTy args ; if isBoxed boxity then repTup listArg else repUnboxedTup listArg } repE (ExplicitSum _ alt arity e) = do { e1 <- repLE e ; repUnboxedSum e1 alt arity } repE (RecordCon { rcon_con_name = c, rcon_flds = flds }) = do { x <- lookupLOcc c; fs <- repFields flds; repRecCon x fs } repE (RecordUpd { rupd_expr = e, rupd_flds = flds }) = do { x <- repLE e; fs <- repUpdFields flds; repRecUpd x fs } repE (ExprWithTySig _ e ty) = do { e1 <- repLE e ; t1 <- repHsSigWcType ty ; repSigExp e1 t1 } repE (ArithSeq _ _ aseq) = case aseq of From e -> do { ds1 <- repLE e; repFrom ds1 } FromThen e1 e2 -> do ds1 <- repLE e1 ds2 <- repLE e2 repFromThen ds1 ds2 FromTo e1 e2 -> do ds1 <- repLE e1 ds2 <- repLE e2 repFromTo ds1 ds2 FromThenTo e1 e2 e3 -> do ds1 <- repLE e1 ds2 <- repLE e2 ds3 <- repLE e3 repFromThenTo ds1 ds2 ds3 repE (HsSpliceE _ splice) = repSplice splice repE (HsStatic _ e) = repLE e >>= rep2 staticEName . (:[]) . unC repE (HsUnboundVar _ uv) = do occ <- occNameLit (unboundVarOcc uv) sname <- repNameS occ repUnboundVar sname repE e@(HsCoreAnn {}) = notHandled "Core annotations" (ppr e) repE e@(HsSCC {}) = notHandled "Cost centres" (ppr e) repE e@(HsTickPragma {}) = notHandled "Tick Pragma" (ppr e) repE e = notHandled "Expression form" (ppr e) ----------------------------------------------------------------------------- -- Building representations of auxillary structures like Match, Clause, Stmt, repMatchTup :: LMatch GhcRn (LHsExpr GhcRn) -> DsM (Core TH.MatchQ) repMatchTup (dL->L _ (Match { m_pats = [p] , m_grhss = GRHSs _ guards (dL->L _ wheres) })) = do { ss1 <- mkGenSyms (collectPatBinders p) ; addBinds ss1 $ do { ; p1 <- repLP p ; (ss2,ds) <- repBinds wheres ; addBinds ss2 $ do { ; gs <- repGuards guards ; match <- repMatch p1 gs ds ; wrapGenSyms (ss1++ss2) match }}} repMatchTup _ = panic "repMatchTup: case alt with more than one arg" repClauseTup :: LMatch GhcRn (LHsExpr GhcRn) -> DsM (Core TH.ClauseQ) repClauseTup (dL->L _ (Match { m_pats = ps , m_grhss = GRHSs _ guards (dL->L _ wheres) })) = do { ss1 <- mkGenSyms (collectPatsBinders ps) ; addBinds ss1 $ do { ps1 <- repLPs ps ; (ss2,ds) <- repBinds wheres ; addBinds ss2 $ do { gs <- repGuards guards ; clause <- repClause ps1 gs ds ; wrapGenSyms (ss1++ss2) clause }}} repClauseTup (dL->L _ (Match _ _ _ (XGRHSs nec))) = noExtCon nec repClauseTup _ = panic "repClauseTup" repGuards :: [LGRHS GhcRn (LHsExpr GhcRn)] -> DsM (Core TH.BodyQ) repGuards [dL->L _ (GRHS _ [] e)] = do {a <- repLE e; repNormal a } repGuards other = do { zs <- mapM repLGRHS other ; let (xs, ys) = unzip zs ; gd <- repGuarded (nonEmptyCoreList ys) ; wrapGenSyms (concat xs) gd } repLGRHS :: LGRHS GhcRn (LHsExpr GhcRn) -> DsM ([GenSymBind], (Core (TH.Q (TH.Guard, TH.Exp)))) repLGRHS (dL->L _ (GRHS _ [dL->L _ (BodyStmt _ e1 _ _)] e2)) = do { guarded <- repLNormalGE e1 e2 ; return ([], guarded) } repLGRHS (dL->L _ (GRHS _ ss rhs)) = do { (gs, ss') <- repLSts ss ; rhs' <- addBinds gs $ repLE rhs ; guarded <- repPatGE (nonEmptyCoreList ss') rhs' ; return (gs, guarded) } repLGRHS _ = panic "repLGRHS" repFields :: HsRecordBinds GhcRn -> DsM (Core [TH.Q TH.FieldExp]) repFields (HsRecFields { rec_flds = flds }) = repList fieldExpQTyConName rep_fld flds where rep_fld :: LHsRecField GhcRn (LHsExpr GhcRn) -> DsM (Core (TH.Q TH.FieldExp)) rep_fld (dL->L _ fld) = do { fn <- lookupLOcc (hsRecFieldSel fld) ; e <- repLE (hsRecFieldArg fld) ; repFieldExp fn e } repUpdFields :: [LHsRecUpdField GhcRn] -> DsM (Core [TH.Q TH.FieldExp]) repUpdFields = repList fieldExpQTyConName rep_fld where rep_fld :: LHsRecUpdField GhcRn -> DsM (Core (TH.Q TH.FieldExp)) rep_fld (dL->L l fld) = case unLoc (hsRecFieldLbl fld) of Unambiguous sel_name _ -> do { fn <- lookupLOcc (cL l sel_name) ; e <- repLE (hsRecFieldArg fld) ; repFieldExp fn e } _ -> notHandled "Ambiguous record updates" (ppr fld) ----------------------------------------------------------------------------- -- Representing Stmt's is tricky, especially if bound variables -- shadow each other. Consider: [| do { x <- f 1; x <- f x; g x } |] -- First gensym new names for every variable in any of the patterns. -- both static (x'1 and x'2), and dynamic ((gensym "x") and (gensym "y")) -- if variables didn't shaddow, the static gensym wouldn't be necessary -- and we could reuse the original names (x and x). -- -- do { x'1 <- gensym "x" -- ; x'2 <- gensym "x" -- ; doE [ BindSt (pvar x'1) [| f 1 |] -- , BindSt (pvar x'2) [| f x |] -- , NoBindSt [| g x |] -- ] -- } -- The strategy is to translate a whole list of do-bindings by building a -- bigger environment, and a bigger set of meta bindings -- (like: x'1 <- gensym "x" ) and then combining these with the translations -- of the expressions within the Do ----------------------------------------------------------------------------- -- The helper function repSts computes the translation of each sub expression -- and a bunch of prefix bindings denoting the dynamic renaming. repLSts :: [LStmt GhcRn (LHsExpr GhcRn)] -> DsM ([GenSymBind], [Core TH.StmtQ]) repLSts stmts = repSts (map unLoc stmts) repSts :: [Stmt GhcRn (LHsExpr GhcRn)] -> DsM ([GenSymBind], [Core TH.StmtQ]) repSts (BindStmt _ p e _ _ : ss) = do { e2 <- repLE e ; ss1 <- mkGenSyms (collectPatBinders p) ; addBinds ss1 $ do { ; p1 <- repLP p; ; (ss2,zs) <- repSts ss ; z <- repBindSt p1 e2 ; return (ss1++ss2, z : zs) }} repSts (LetStmt _ (dL->L _ bs) : ss) = do { (ss1,ds) <- repBinds bs ; z <- repLetSt ds ; (ss2,zs) <- addBinds ss1 (repSts ss) ; return (ss1++ss2, z : zs) } repSts (BodyStmt _ e _ _ : ss) = do { e2 <- repLE e ; z <- repNoBindSt e2 ; (ss2,zs) <- repSts ss ; return (ss2, z : zs) } repSts (ParStmt _ stmt_blocks _ _ : ss) = do { (ss_s, stmt_blocks1) <- mapAndUnzipM rep_stmt_block stmt_blocks ; let stmt_blocks2 = nonEmptyCoreList stmt_blocks1 ss1 = concat ss_s ; z <- repParSt stmt_blocks2 ; (ss2, zs) <- addBinds ss1 (repSts ss) ; return (ss1++ss2, z : zs) } where rep_stmt_block :: ParStmtBlock GhcRn GhcRn -> DsM ([GenSymBind], Core [TH.StmtQ]) rep_stmt_block (ParStmtBlock _ stmts _ _) = do { (ss1, zs) <- repSts (map unLoc stmts) ; zs1 <- coreList stmtQTyConName zs ; return (ss1, zs1) } rep_stmt_block (XParStmtBlock nec) = noExtCon nec repSts [LastStmt _ e _ _] = do { e2 <- repLE e ; z <- repNoBindSt e2 ; return ([], [z]) } repSts (stmt@RecStmt{} : ss) = do { let binders = collectLStmtsBinders (recS_stmts stmt) ; ss1 <- mkGenSyms binders -- Bring all of binders in the recursive group into scope for the -- whole group. ; (ss1_other,rss) <- addBinds ss1 $ repSts (map unLoc (recS_stmts stmt)) ; MASSERT(sort ss1 == sort ss1_other) ; z <- repRecSt (nonEmptyCoreList rss) ; (ss2,zs) <- addBinds ss1 (repSts ss) ; return (ss1++ss2, z : zs) } repSts [] = return ([],[]) repSts other = notHandled "Exotic statement" (ppr other) ----------------------------------------------------------- -- Bindings ----------------------------------------------------------- repBinds :: HsLocalBinds GhcRn -> DsM ([GenSymBind], Core [TH.DecQ]) repBinds (EmptyLocalBinds _) = do { core_list <- coreList decQTyConName [] ; return ([], core_list) } repBinds (HsIPBinds _ (IPBinds _ decs)) = do { ips <- mapM rep_implicit_param_bind decs ; core_list <- coreList decQTyConName (de_loc (sort_by_loc ips)) ; return ([], core_list) } repBinds b@(HsIPBinds _ XHsIPBinds {}) = notHandled "Implicit parameter binds extension" (ppr b) repBinds (HsValBinds _ decs) = do { let { bndrs = hsScopedTvBinders decs ++ collectHsValBinders decs } -- No need to worry about detailed scopes within -- the binding group, because we are talking Names -- here, so we can safely treat it as a mutually -- recursive group -- For hsScopedTvBinders see Note [Scoped type variables in bindings] ; ss <- mkGenSyms bndrs ; prs <- addBinds ss (rep_val_binds decs) ; core_list <- coreList decQTyConName (de_loc (sort_by_loc prs)) ; return (ss, core_list) } repBinds b@(XHsLocalBindsLR {}) = notHandled "Local binds extensions" (ppr b) rep_implicit_param_bind :: LIPBind GhcRn -> DsM (SrcSpan, Core TH.DecQ) rep_implicit_param_bind (dL->L loc (IPBind _ ename (dL->L _ rhs))) = do { name <- case ename of Left (dL->L _ n) -> rep_implicit_param_name n Right _ -> panic "rep_implicit_param_bind: post typechecking" ; rhs' <- repE rhs ; ipb <- repImplicitParamBind name rhs' ; return (loc, ipb) } rep_implicit_param_bind (dL->L _ b@(XIPBind _)) = notHandled "Implicit parameter bind extension" (ppr b) rep_implicit_param_bind _ = panic "rep_implicit_param_bind: Impossible Match" -- due to #15884 rep_implicit_param_name :: HsIPName -> DsM (Core String) rep_implicit_param_name (HsIPName name) = coreStringLit (unpackFS name) rep_val_binds :: HsValBinds GhcRn -> DsM [(SrcSpan, Core TH.DecQ)] -- Assumes: all the binders of the binding are already in the meta-env rep_val_binds (XValBindsLR (NValBinds binds sigs)) = do { core1 <- rep_binds (unionManyBags (map snd binds)) ; core2 <- rep_sigs sigs ; return (core1 ++ core2) } rep_val_binds (ValBinds _ _ _) = panic "rep_val_binds: ValBinds" rep_binds :: LHsBinds GhcRn -> DsM [(SrcSpan, Core TH.DecQ)] rep_binds = mapM rep_bind . bagToList rep_bind :: LHsBind GhcRn -> DsM (SrcSpan, Core TH.DecQ) -- Assumes: all the binders of the binding are already in the meta-env -- Note GHC treats declarations of a variable (not a pattern) -- e.g. x = g 5 as a Fun MonoBinds. This is indicated by a single match -- with an empty list of patterns rep_bind (dL->L loc (FunBind { fun_id = fn, fun_matches = MG { mg_alts = (dL->L _ [dL->L _ (Match { m_pats = [] , m_grhss = GRHSs _ guards (dL->L _ wheres) } )]) } })) = do { (ss,wherecore) <- repBinds wheres ; guardcore <- addBinds ss (repGuards guards) ; fn' <- lookupLBinder fn ; p <- repPvar fn' ; ans <- repVal p guardcore wherecore ; ans' <- wrapGenSyms ss ans ; return (loc, ans') } rep_bind (dL->L loc (FunBind { fun_id = fn , fun_matches = MG { mg_alts = (dL->L _ ms) } })) = do { ms1 <- mapM repClauseTup ms ; fn' <- lookupLBinder fn ; ans <- repFun fn' (nonEmptyCoreList ms1) ; return (loc, ans) } rep_bind (dL->L _ (FunBind { fun_matches = XMatchGroup nec })) = noExtCon nec rep_bind (dL->L loc (PatBind { pat_lhs = pat , pat_rhs = GRHSs _ guards (dL->L _ wheres) })) = do { patcore <- repLP pat ; (ss,wherecore) <- repBinds wheres ; guardcore <- addBinds ss (repGuards guards) ; ans <- repVal patcore guardcore wherecore ; ans' <- wrapGenSyms ss ans ; return (loc, ans') } rep_bind (dL->L _ (PatBind _ _ (XGRHSs nec) _)) = noExtCon nec rep_bind (dL->L _ (VarBind { var_id = v, var_rhs = e})) = do { v' <- lookupBinder v ; e2 <- repLE e ; x <- repNormal e2 ; patcore <- repPvar v' ; empty_decls <- coreList decQTyConName [] ; ans <- repVal patcore x empty_decls ; return (srcLocSpan (getSrcLoc v), ans) } rep_bind (dL->L _ (AbsBinds {})) = panic "rep_bind: AbsBinds" rep_bind (dL->L loc (PatSynBind _ (PSB { psb_id = syn , psb_args = args , psb_def = pat , psb_dir = dir }))) = do { syn' <- lookupLBinder syn ; dir' <- repPatSynDir dir ; ss <- mkGenArgSyms args ; patSynD' <- addBinds ss ( do { args' <- repPatSynArgs args ; pat' <- repLP pat ; repPatSynD syn' args' dir' pat' }) ; patSynD'' <- wrapGenArgSyms args ss patSynD' ; return (loc, patSynD'') } where mkGenArgSyms :: HsPatSynDetails (Located Name) -> DsM [GenSymBind] -- for Record Pattern Synonyms we want to conflate the selector -- and the pattern-only names in order to provide a nicer TH -- API. Whereas inside GHC, record pattern synonym selectors and -- their pattern-only bound right hand sides have different names, -- we want to treat them the same in TH. This is the reason why we -- need an adjusted mkGenArgSyms in the `RecCon` case below. mkGenArgSyms (PrefixCon args) = mkGenSyms (map unLoc args) mkGenArgSyms (InfixCon arg1 arg2) = mkGenSyms [unLoc arg1, unLoc arg2] mkGenArgSyms (RecCon fields) = do { let pats = map (unLoc . recordPatSynPatVar) fields sels = map (unLoc . recordPatSynSelectorId) fields ; ss <- mkGenSyms sels ; return $ replaceNames (zip sels pats) ss } replaceNames selsPats genSyms = [ (pat, id) | (sel, id) <- genSyms, (sel', pat) <- selsPats , sel == sel' ] wrapGenArgSyms :: HsPatSynDetails (Located Name) -> [GenSymBind] -> Core TH.DecQ -> DsM (Core TH.DecQ) wrapGenArgSyms (RecCon _) _ dec = return dec wrapGenArgSyms _ ss dec = wrapGenSyms ss dec rep_bind (dL->L _ (PatSynBind _ (XPatSynBind nec))) = noExtCon nec rep_bind (dL->L _ (XHsBindsLR nec)) = noExtCon nec rep_bind _ = panic "rep_bind: Impossible match!" -- due to #15884 repPatSynD :: Core TH.Name -> Core TH.PatSynArgsQ -> Core TH.PatSynDirQ -> Core TH.PatQ -> DsM (Core TH.DecQ) repPatSynD (MkC syn) (MkC args) (MkC dir) (MkC pat) = rep2 patSynDName [syn, args, dir, pat] repPatSynArgs :: HsPatSynDetails (Located Name) -> DsM (Core TH.PatSynArgsQ) repPatSynArgs (PrefixCon args) = do { args' <- repList nameTyConName lookupLOcc args ; repPrefixPatSynArgs args' } repPatSynArgs (InfixCon arg1 arg2) = do { arg1' <- lookupLOcc arg1 ; arg2' <- lookupLOcc arg2 ; repInfixPatSynArgs arg1' arg2' } repPatSynArgs (RecCon fields) = do { sels' <- repList nameTyConName lookupLOcc sels ; repRecordPatSynArgs sels' } where sels = map recordPatSynSelectorId fields repPrefixPatSynArgs :: Core [TH.Name] -> DsM (Core TH.PatSynArgsQ) repPrefixPatSynArgs (MkC nms) = rep2 prefixPatSynName [nms] repInfixPatSynArgs :: Core TH.Name -> Core TH.Name -> DsM (Core TH.PatSynArgsQ) repInfixPatSynArgs (MkC nm1) (MkC nm2) = rep2 infixPatSynName [nm1, nm2] repRecordPatSynArgs :: Core [TH.Name] -> DsM (Core TH.PatSynArgsQ) repRecordPatSynArgs (MkC sels) = rep2 recordPatSynName [sels] repPatSynDir :: HsPatSynDir GhcRn -> DsM (Core TH.PatSynDirQ) repPatSynDir Unidirectional = rep2 unidirPatSynName [] repPatSynDir ImplicitBidirectional = rep2 implBidirPatSynName [] repPatSynDir (ExplicitBidirectional (MG { mg_alts = (dL->L _ clauses) })) = do { clauses' <- mapM repClauseTup clauses ; repExplBidirPatSynDir (nonEmptyCoreList clauses') } repPatSynDir (ExplicitBidirectional (XMatchGroup nec)) = noExtCon nec repExplBidirPatSynDir :: Core [TH.ClauseQ] -> DsM (Core TH.PatSynDirQ) repExplBidirPatSynDir (MkC cls) = rep2 explBidirPatSynName [cls] ----------------------------------------------------------------------------- -- Since everything in a Bind is mutually recursive we need rename all -- all the variables simultaneously. For example: -- [| AndMonoBinds (f x = x + g 2) (g x = f 1 + 2) |] would translate to -- do { f'1 <- gensym "f" -- ; g'2 <- gensym "g" -- ; [ do { x'3 <- gensym "x"; fun f'1 [pvar x'3] [| x + g2 |]}, -- do { x'4 <- gensym "x"; fun g'2 [pvar x'4] [| f 1 + 2 |]} -- ]} -- This requires collecting the bindings (f'1 <- gensym "f"), and the -- environment ( f |-> f'1 ) from each binding, and then unioning them -- together. As we do this we collect GenSymBinds's which represent the renamed -- variables bound by the Bindings. In order not to lose track of these -- representations we build a shadow datatype MB with the same structure as -- MonoBinds, but which has slots for the representations ----------------------------------------------------------------------------- -- GHC allows a more general form of lambda abstraction than specified -- by Haskell 98. In particular it allows guarded lambda's like : -- (\ x | even x -> 0 | odd x -> 1) at the moment we can't represent this in -- Haskell Template's Meta.Exp type so we punt if it isn't a simple thing like -- (\ p1 .. pn -> exp) by causing an error. repLambda :: LMatch GhcRn (LHsExpr GhcRn) -> DsM (Core TH.ExpQ) repLambda (dL->L _ (Match { m_pats = ps , m_grhss = GRHSs _ [dL->L _ (GRHS _ [] e)] (dL->L _ (EmptyLocalBinds _)) } )) = do { let bndrs = collectPatsBinders ps ; ; ss <- mkGenSyms bndrs ; lam <- addBinds ss ( do { xs <- repLPs ps; body <- repLE e; repLam xs body }) ; wrapGenSyms ss lam } repLambda (dL->L _ m) = notHandled "Guarded lambdas" (pprMatch m) ----------------------------------------------------------------------------- -- Patterns -- repP deals with patterns. It assumes that we have already -- walked over the pattern(s) once to collect the binders, and -- have extended the environment. So every pattern-bound -- variable should already appear in the environment. -- Process a list of patterns repLPs :: [LPat GhcRn] -> DsM (Core [TH.PatQ]) repLPs ps = repList patQTyConName repLP ps repLP :: LPat GhcRn -> DsM (Core TH.PatQ) repLP p = repP (unLoc p) repP :: Pat GhcRn -> DsM (Core TH.PatQ) repP (WildPat _) = repPwild repP (LitPat _ l) = do { l2 <- repLiteral l; repPlit l2 } repP (VarPat _ x) = do { x' <- lookupBinder (unLoc x); repPvar x' } repP (LazyPat _ p) = do { p1 <- repLP p; repPtilde p1 } repP (BangPat _ p) = do { p1 <- repLP p; repPbang p1 } repP (AsPat _ x p) = do { x' <- lookupLBinder x; p1 <- repLP p ; repPaspat x' p1 } repP (ParPat _ p) = repLP p repP (ListPat Nothing ps) = do { qs <- repLPs ps; repPlist qs } repP (ListPat (Just e) ps) = do { p <- repP (ListPat Nothing ps) ; e' <- repE (syn_expr e) ; repPview e' p} repP (TuplePat _ ps boxed) | isBoxed boxed = do { qs <- repLPs ps; repPtup qs } | otherwise = do { qs <- repLPs ps; repPunboxedTup qs } repP (SumPat _ p alt arity) = do { p1 <- repLP p ; repPunboxedSum p1 alt arity } repP (ConPatIn dc details) = do { con_str <- lookupLOcc dc ; case details of PrefixCon ps -> do { qs <- repLPs ps; repPcon con_str qs } RecCon rec -> do { fps <- repList fieldPatQTyConName rep_fld (rec_flds rec) ; repPrec con_str fps } InfixCon p1 p2 -> do { p1' <- repLP p1; p2' <- repLP p2; repPinfix p1' con_str p2' } } where rep_fld :: LHsRecField GhcRn (LPat GhcRn) -> DsM (Core (TH.Name,TH.PatQ)) rep_fld (dL->L _ fld) = do { MkC v <- lookupLOcc (hsRecFieldSel fld) ; MkC p <- repLP (hsRecFieldArg fld) ; rep2 fieldPatName [v,p] } repP (NPat _ (dL->L _ l) Nothing _) = do { a <- repOverloadedLiteral l ; repPlit a } repP (ViewPat _ e p) = do { e' <- repLE e; p' <- repLP p; repPview e' p' } repP p@(NPat _ _ (Just _) _) = notHandled "Negative overloaded patterns" (ppr p) repP (SigPat _ p t) = do { p' <- repLP p ; t' <- repLTy (hsSigWcType t) ; repPsig p' t' } repP (SplicePat _ splice) = repSplice splice repP other = notHandled "Exotic pattern" (ppr other) ---------------------------------------------------------- -- Declaration ordering helpers sort_by_loc :: [(SrcSpan, a)] -> [(SrcSpan, a)] sort_by_loc xs = sortBy comp xs where comp x y = compare (fst x) (fst y) de_loc :: [(a, b)] -> [b] de_loc = map snd ---------------------------------------------------------- -- The meta-environment -- A name/identifier association for fresh names of locally bound entities type GenSymBind = (Name, Id) -- Gensym the string and bind it to the Id -- I.e. (x, x_id) means -- let x_id = gensym "x" in ... -- Generate a fresh name for a locally bound entity mkGenSyms :: [Name] -> DsM [GenSymBind] -- We can use the existing name. For example: -- [| \x_77 -> x_77 + x_77 |] -- desugars to -- do { x_77 <- genSym "x"; .... } -- We use the same x_77 in the desugared program, but with the type Bndr -- instead of Int -- -- We do make it an Internal name, though (hence localiseName) -- -- Nevertheless, it's monadic because we have to generate nameTy mkGenSyms ns = do { var_ty <- lookupType nameTyConName ; return [(nm, mkLocalId (localiseName nm) var_ty) | nm <- ns] } addBinds :: [GenSymBind] -> DsM a -> DsM a -- Add a list of fresh names for locally bound entities to the -- meta environment (which is part of the state carried around -- by the desugarer monad) addBinds bs m = dsExtendMetaEnv (mkNameEnv [(n,DsBound id) | (n,id) <- bs]) m -- Look up a locally bound name -- lookupLBinder :: Located Name -> DsM (Core TH.Name) lookupLBinder n = lookupBinder (unLoc n) lookupBinder :: Name -> DsM (Core TH.Name) lookupBinder = lookupOcc -- Binders are brought into scope before the pattern or what-not is -- desugared. Moreover, in instance declaration the binder of a method -- will be the selector Id and hence a global; so we need the -- globalVar case of lookupOcc -- Look up a name that is either locally bound or a global name -- -- * If it is a global name, generate the "original name" representation (ie, -- the : form) for the associated entity -- lookupLOcc :: Located Name -> DsM (Core TH.Name) -- Lookup an occurrence; it can't be a splice. -- Use the in-scope bindings if they exist lookupLOcc n = lookupOcc (unLoc n) lookupOcc :: Name -> DsM (Core TH.Name) lookupOcc n = do { mb_val <- dsLookupMetaEnv n ; case mb_val of Nothing -> globalVar n Just (DsBound x) -> return (coreVar x) Just (DsSplice _) -> pprPanic "repE:lookupOcc" (ppr n) } globalVar :: Name -> DsM (Core TH.Name) -- Not bound by the meta-env -- Could be top-level; or could be local -- f x = $(g [| x |]) -- Here the x will be local globalVar name | isExternalName name = do { MkC mod <- coreStringLit name_mod ; MkC pkg <- coreStringLit name_pkg ; MkC occ <- nameLit name ; rep2 mk_varg [pkg,mod,occ] } | otherwise = do { MkC occ <- nameLit name ; MkC uni <- coreIntegerLit (toInteger $ getKey (getUnique name)) ; rep2 mkNameLName [occ,uni] } where mod = ASSERT( isExternalName name) nameModule name name_mod = moduleNameString (moduleName mod) name_pkg = unitIdString (moduleUnitId mod) name_occ = nameOccName name mk_varg | OccName.isDataOcc name_occ = mkNameG_dName | OccName.isVarOcc name_occ = mkNameG_vName | OccName.isTcOcc name_occ = mkNameG_tcName | otherwise = pprPanic "DsMeta.globalVar" (ppr name) lookupType :: Name -- Name of type constructor (e.g. TH.ExpQ) -> DsM Type -- The type lookupType tc_name = do { tc <- dsLookupTyCon tc_name ; return (mkTyConApp tc []) } wrapGenSyms :: [GenSymBind] -> Core (TH.Q a) -> DsM (Core (TH.Q a)) -- wrapGenSyms [(nm1,id1), (nm2,id2)] y -- --> bindQ (gensym nm1) (\ id1 -> -- bindQ (gensym nm2 (\ id2 -> -- y)) wrapGenSyms binds body@(MkC b) = do { var_ty <- lookupType nameTyConName ; go var_ty binds } where [elt_ty] = tcTyConAppArgs (exprType b) -- b :: Q a, so we can get the type 'a' by looking at the -- argument type. NB: this relies on Q being a data/newtype, -- not a type synonym go _ [] = return body go var_ty ((name,id) : binds) = do { MkC body' <- go var_ty binds ; lit_str <- nameLit name ; gensym_app <- repGensym lit_str ; repBindQ var_ty elt_ty gensym_app (MkC (Lam id body')) } nameLit :: Name -> DsM (Core String) nameLit n = coreStringLit (occNameString (nameOccName n)) occNameLit :: OccName -> DsM (Core String) occNameLit name = coreStringLit (occNameString name) -- %********************************************************************* -- %* * -- Constructing code -- %* * -- %********************************************************************* ----------------------------------------------------------------------------- -- PHANTOM TYPES for consistency. In order to make sure we do this correct -- we invent a new datatype which uses phantom types. newtype Core a = MkC CoreExpr unC :: Core a -> CoreExpr unC (MkC x) = x rep2 :: Name -> [ CoreExpr ] -> DsM (Core a) rep2 n xs = do { id <- dsLookupGlobalId n ; return (MkC (foldl' App (Var id) xs)) } dataCon' :: Name -> [CoreExpr] -> DsM (Core a) dataCon' n args = do { id <- dsLookupDataCon n ; return $ MkC $ mkCoreConApps id args } dataCon :: Name -> DsM (Core a) dataCon n = dataCon' n [] -- %********************************************************************* -- %* * -- The 'smart constructors' -- %* * -- %********************************************************************* --------------- Patterns ----------------- repPlit :: Core TH.Lit -> DsM (Core TH.PatQ) repPlit (MkC l) = rep2 litPName [l] repPvar :: Core TH.Name -> DsM (Core TH.PatQ) repPvar (MkC s) = rep2 varPName [s] repPtup :: Core [TH.PatQ] -> DsM (Core TH.PatQ) repPtup (MkC ps) = rep2 tupPName [ps] repPunboxedTup :: Core [TH.PatQ] -> DsM (Core TH.PatQ) repPunboxedTup (MkC ps) = rep2 unboxedTupPName [ps] repPunboxedSum :: Core TH.PatQ -> TH.SumAlt -> TH.SumArity -> DsM (Core TH.PatQ) -- Note: not Core TH.SumAlt or Core TH.SumArity; it's easier to be direct here repPunboxedSum (MkC p) alt arity = do { dflags <- getDynFlags ; rep2 unboxedSumPName [ p , mkIntExprInt dflags alt , mkIntExprInt dflags arity ] } repPcon :: Core TH.Name -> Core [TH.PatQ] -> DsM (Core TH.PatQ) repPcon (MkC s) (MkC ps) = rep2 conPName [s, ps] repPrec :: Core TH.Name -> Core [(TH.Name,TH.PatQ)] -> DsM (Core TH.PatQ) repPrec (MkC c) (MkC rps) = rep2 recPName [c,rps] repPinfix :: Core TH.PatQ -> Core TH.Name -> Core TH.PatQ -> DsM (Core TH.PatQ) repPinfix (MkC p1) (MkC n) (MkC p2) = rep2 infixPName [p1, n, p2] repPtilde :: Core TH.PatQ -> DsM (Core TH.PatQ) repPtilde (MkC p) = rep2 tildePName [p] repPbang :: Core TH.PatQ -> DsM (Core TH.PatQ) repPbang (MkC p) = rep2 bangPName [p] repPaspat :: Core TH.Name -> Core TH.PatQ -> DsM (Core TH.PatQ) repPaspat (MkC s) (MkC p) = rep2 asPName [s, p] repPwild :: DsM (Core TH.PatQ) repPwild = rep2 wildPName [] repPlist :: Core [TH.PatQ] -> DsM (Core TH.PatQ) repPlist (MkC ps) = rep2 listPName [ps] repPview :: Core TH.ExpQ -> Core TH.PatQ -> DsM (Core TH.PatQ) repPview (MkC e) (MkC p) = rep2 viewPName [e,p] repPsig :: Core TH.PatQ -> Core TH.TypeQ -> DsM (Core TH.PatQ) repPsig (MkC p) (MkC t) = rep2 sigPName [p, t] --------------- Expressions ----------------- repVarOrCon :: Name -> Core TH.Name -> DsM (Core TH.ExpQ) repVarOrCon vc str | isDataOcc (nameOccName vc) = repCon str | otherwise = repVar str repVar :: Core TH.Name -> DsM (Core TH.ExpQ) repVar (MkC s) = rep2 varEName [s] repCon :: Core TH.Name -> DsM (Core TH.ExpQ) repCon (MkC s) = rep2 conEName [s] repLit :: Core TH.Lit -> DsM (Core TH.ExpQ) repLit (MkC c) = rep2 litEName [c] repApp :: Core TH.ExpQ -> Core TH.ExpQ -> DsM (Core TH.ExpQ) repApp (MkC x) (MkC y) = rep2 appEName [x,y] repAppType :: Core TH.ExpQ -> Core TH.TypeQ -> DsM (Core TH.ExpQ) repAppType (MkC x) (MkC y) = rep2 appTypeEName [x,y] repLam :: Core [TH.PatQ] -> Core TH.ExpQ -> DsM (Core TH.ExpQ) repLam (MkC ps) (MkC e) = rep2 lamEName [ps, e] repLamCase :: Core [TH.MatchQ] -> DsM (Core TH.ExpQ) repLamCase (MkC ms) = rep2 lamCaseEName [ms] repTup :: Core [Maybe TH.ExpQ] -> DsM (Core TH.ExpQ) repTup (MkC es) = rep2 tupEName [es] repUnboxedTup :: Core [Maybe TH.ExpQ] -> DsM (Core TH.ExpQ) repUnboxedTup (MkC es) = rep2 unboxedTupEName [es] repUnboxedSum :: Core TH.ExpQ -> TH.SumAlt -> TH.SumArity -> DsM (Core TH.ExpQ) -- Note: not Core TH.SumAlt or Core TH.SumArity; it's easier to be direct here repUnboxedSum (MkC e) alt arity = do { dflags <- getDynFlags ; rep2 unboxedSumEName [ e , mkIntExprInt dflags alt , mkIntExprInt dflags arity ] } repCond :: Core TH.ExpQ -> Core TH.ExpQ -> Core TH.ExpQ -> DsM (Core TH.ExpQ) repCond (MkC x) (MkC y) (MkC z) = rep2 condEName [x,y,z] repMultiIf :: Core [TH.Q (TH.Guard, TH.Exp)] -> DsM (Core TH.ExpQ) repMultiIf (MkC alts) = rep2 multiIfEName [alts] repLetE :: Core [TH.DecQ] -> Core TH.ExpQ -> DsM (Core TH.ExpQ) repLetE (MkC ds) (MkC e) = rep2 letEName [ds, e] repCaseE :: Core TH.ExpQ -> Core [TH.MatchQ] -> DsM (Core TH.ExpQ) repCaseE (MkC e) (MkC ms) = rep2 caseEName [e, ms] repDoE :: Core [TH.StmtQ] -> DsM (Core TH.ExpQ) repDoE (MkC ss) = rep2 doEName [ss] repMDoE :: Core [TH.StmtQ] -> DsM (Core TH.ExpQ) repMDoE (MkC ss) = rep2 mdoEName [ss] repComp :: Core [TH.StmtQ] -> DsM (Core TH.ExpQ) repComp (MkC ss) = rep2 compEName [ss] repListExp :: Core [TH.ExpQ] -> DsM (Core TH.ExpQ) repListExp (MkC es) = rep2 listEName [es] repSigExp :: Core TH.ExpQ -> Core TH.TypeQ -> DsM (Core TH.ExpQ) repSigExp (MkC e) (MkC t) = rep2 sigEName [e,t] repRecCon :: Core TH.Name -> Core [TH.Q TH.FieldExp]-> DsM (Core TH.ExpQ) repRecCon (MkC c) (MkC fs) = rep2 recConEName [c,fs] repRecUpd :: Core TH.ExpQ -> Core [TH.Q TH.FieldExp] -> DsM (Core TH.ExpQ) repRecUpd (MkC e) (MkC fs) = rep2 recUpdEName [e,fs] repFieldExp :: Core TH.Name -> Core TH.ExpQ -> DsM (Core (TH.Q TH.FieldExp)) repFieldExp (MkC n) (MkC x) = rep2 fieldExpName [n,x] repInfixApp :: Core TH.ExpQ -> Core TH.ExpQ -> Core TH.ExpQ -> DsM (Core TH.ExpQ) repInfixApp (MkC x) (MkC y) (MkC z) = rep2 infixAppName [x,y,z] repSectionL :: Core TH.ExpQ -> Core TH.ExpQ -> DsM (Core TH.ExpQ) repSectionL (MkC x) (MkC y) = rep2 sectionLName [x,y] repSectionR :: Core TH.ExpQ -> Core TH.ExpQ -> DsM (Core TH.ExpQ) repSectionR (MkC x) (MkC y) = rep2 sectionRName [x,y] repImplicitParamVar :: Core String -> DsM (Core TH.ExpQ) repImplicitParamVar (MkC x) = rep2 implicitParamVarEName [x] ------------ Right hand sides (guarded expressions) ---- repGuarded :: Core [TH.Q (TH.Guard, TH.Exp)] -> DsM (Core TH.BodyQ) repGuarded (MkC pairs) = rep2 guardedBName [pairs] repNormal :: Core TH.ExpQ -> DsM (Core TH.BodyQ) repNormal (MkC e) = rep2 normalBName [e] ------------ Guards ---- repLNormalGE :: LHsExpr GhcRn -> LHsExpr GhcRn -> DsM (Core (TH.Q (TH.Guard, TH.Exp))) repLNormalGE g e = do g' <- repLE g e' <- repLE e repNormalGE g' e' repNormalGE :: Core TH.ExpQ -> Core TH.ExpQ -> DsM (Core (TH.Q (TH.Guard, TH.Exp))) repNormalGE (MkC g) (MkC e) = rep2 normalGEName [g, e] repPatGE :: Core [TH.StmtQ] -> Core TH.ExpQ -> DsM (Core (TH.Q (TH.Guard, TH.Exp))) repPatGE (MkC ss) (MkC e) = rep2 patGEName [ss, e] ------------- Stmts ------------------- repBindSt :: Core TH.PatQ -> Core TH.ExpQ -> DsM (Core TH.StmtQ) repBindSt (MkC p) (MkC e) = rep2 bindSName [p,e] repLetSt :: Core [TH.DecQ] -> DsM (Core TH.StmtQ) repLetSt (MkC ds) = rep2 letSName [ds] repNoBindSt :: Core TH.ExpQ -> DsM (Core TH.StmtQ) repNoBindSt (MkC e) = rep2 noBindSName [e] repParSt :: Core [[TH.StmtQ]] -> DsM (Core TH.StmtQ) repParSt (MkC sss) = rep2 parSName [sss] repRecSt :: Core [TH.StmtQ] -> DsM (Core TH.StmtQ) repRecSt (MkC ss) = rep2 recSName [ss] -------------- Range (Arithmetic sequences) ----------- repFrom :: Core TH.ExpQ -> DsM (Core TH.ExpQ) repFrom (MkC x) = rep2 fromEName [x] repFromThen :: Core TH.ExpQ -> Core TH.ExpQ -> DsM (Core TH.ExpQ) repFromThen (MkC x) (MkC y) = rep2 fromThenEName [x,y] repFromTo :: Core TH.ExpQ -> Core TH.ExpQ -> DsM (Core TH.ExpQ) repFromTo (MkC x) (MkC y) = rep2 fromToEName [x,y] repFromThenTo :: Core TH.ExpQ -> Core TH.ExpQ -> Core TH.ExpQ -> DsM (Core TH.ExpQ) repFromThenTo (MkC x) (MkC y) (MkC z) = rep2 fromThenToEName [x,y,z] ------------ Match and Clause Tuples ----------- repMatch :: Core TH.PatQ -> Core TH.BodyQ -> Core [TH.DecQ] -> DsM (Core TH.MatchQ) repMatch (MkC p) (MkC bod) (MkC ds) = rep2 matchName [p, bod, ds] repClause :: Core [TH.PatQ] -> Core TH.BodyQ -> Core [TH.DecQ] -> DsM (Core TH.ClauseQ) repClause (MkC ps) (MkC bod) (MkC ds) = rep2 clauseName [ps, bod, ds] -------------- Dec ----------------------------- repVal :: Core TH.PatQ -> Core TH.BodyQ -> Core [TH.DecQ] -> DsM (Core TH.DecQ) repVal (MkC p) (MkC b) (MkC ds) = rep2 valDName [p, b, ds] repFun :: Core TH.Name -> Core [TH.ClauseQ] -> DsM (Core TH.DecQ) repFun (MkC nm) (MkC b) = rep2 funDName [nm, b] repData :: Core TH.CxtQ -> Core TH.Name -> Either (Core [TH.TyVarBndrQ]) (Core (Maybe [TH.TyVarBndrQ]), Core TH.TypeQ) -> Core (Maybe TH.KindQ) -> Core [TH.ConQ] -> Core [TH.DerivClauseQ] -> DsM (Core TH.DecQ) repData (MkC cxt) (MkC nm) (Left (MkC tvs)) (MkC ksig) (MkC cons) (MkC derivs) = rep2 dataDName [cxt, nm, tvs, ksig, cons, derivs] repData (MkC cxt) (MkC _) (Right (MkC mb_bndrs, MkC ty)) (MkC ksig) (MkC cons) (MkC derivs) = rep2 dataInstDName [cxt, mb_bndrs, ty, ksig, cons, derivs] repNewtype :: Core TH.CxtQ -> Core TH.Name -> Either (Core [TH.TyVarBndrQ]) (Core (Maybe [TH.TyVarBndrQ]), Core TH.TypeQ) -> Core (Maybe TH.KindQ) -> Core TH.ConQ -> Core [TH.DerivClauseQ] -> DsM (Core TH.DecQ) repNewtype (MkC cxt) (MkC nm) (Left (MkC tvs)) (MkC ksig) (MkC con) (MkC derivs) = rep2 newtypeDName [cxt, nm, tvs, ksig, con, derivs] repNewtype (MkC cxt) (MkC _) (Right (MkC mb_bndrs, MkC ty)) (MkC ksig) (MkC con) (MkC derivs) = rep2 newtypeInstDName [cxt, mb_bndrs, ty, ksig, con, derivs] repTySyn :: Core TH.Name -> Core [TH.TyVarBndrQ] -> Core TH.TypeQ -> DsM (Core TH.DecQ) repTySyn (MkC nm) (MkC tvs) (MkC rhs) = rep2 tySynDName [nm, tvs, rhs] repInst :: Core (Maybe TH.Overlap) -> Core TH.CxtQ -> Core TH.TypeQ -> Core [TH.DecQ] -> DsM (Core TH.DecQ) repInst (MkC o) (MkC cxt) (MkC ty) (MkC ds) = rep2 instanceWithOverlapDName [o, cxt, ty, ds] repDerivStrategy :: Maybe (LDerivStrategy GhcRn) -> DsM (Core (Maybe TH.DerivStrategyQ)) repDerivStrategy mds = case mds of Nothing -> nothing Just ds -> case unLoc ds of StockStrategy -> just =<< repStockStrategy AnyclassStrategy -> just =<< repAnyclassStrategy NewtypeStrategy -> just =<< repNewtypeStrategy ViaStrategy ty -> do ty' <- repLTy (hsSigType ty) via_strat <- repViaStrategy ty' just via_strat where nothing = coreNothing derivStrategyQTyConName just = coreJust derivStrategyQTyConName repStockStrategy :: DsM (Core TH.DerivStrategyQ) repStockStrategy = rep2 stockStrategyName [] repAnyclassStrategy :: DsM (Core TH.DerivStrategyQ) repAnyclassStrategy = rep2 anyclassStrategyName [] repNewtypeStrategy :: DsM (Core TH.DerivStrategyQ) repNewtypeStrategy = rep2 newtypeStrategyName [] repViaStrategy :: Core TH.TypeQ -> DsM (Core TH.DerivStrategyQ) repViaStrategy (MkC t) = rep2 viaStrategyName [t] repOverlap :: Maybe OverlapMode -> DsM (Core (Maybe TH.Overlap)) repOverlap mb = case mb of Nothing -> nothing Just o -> case o of NoOverlap _ -> nothing Overlappable _ -> just =<< dataCon overlappableDataConName Overlapping _ -> just =<< dataCon overlappingDataConName Overlaps _ -> just =<< dataCon overlapsDataConName Incoherent _ -> just =<< dataCon incoherentDataConName where nothing = coreNothing overlapTyConName just = coreJust overlapTyConName repClass :: Core TH.CxtQ -> Core TH.Name -> Core [TH.TyVarBndrQ] -> Core [TH.FunDep] -> Core [TH.DecQ] -> DsM (Core TH.DecQ) repClass (MkC cxt) (MkC cls) (MkC tvs) (MkC fds) (MkC ds) = rep2 classDName [cxt, cls, tvs, fds, ds] repDeriv :: Core (Maybe TH.DerivStrategyQ) -> Core TH.CxtQ -> Core TH.TypeQ -> DsM (Core TH.DecQ) repDeriv (MkC ds) (MkC cxt) (MkC ty) = rep2 standaloneDerivWithStrategyDName [ds, cxt, ty] repPragInl :: Core TH.Name -> Core TH.Inline -> Core TH.RuleMatch -> Core TH.Phases -> DsM (Core TH.DecQ) repPragInl (MkC nm) (MkC inline) (MkC rm) (MkC phases) = rep2 pragInlDName [nm, inline, rm, phases] repPragSpec :: Core TH.Name -> Core TH.TypeQ -> Core TH.Phases -> DsM (Core TH.DecQ) repPragSpec (MkC nm) (MkC ty) (MkC phases) = rep2 pragSpecDName [nm, ty, phases] repPragSpecInl :: Core TH.Name -> Core TH.TypeQ -> Core TH.Inline -> Core TH.Phases -> DsM (Core TH.DecQ) repPragSpecInl (MkC nm) (MkC ty) (MkC inline) (MkC phases) = rep2 pragSpecInlDName [nm, ty, inline, phases] repPragSpecInst :: Core TH.TypeQ -> DsM (Core TH.DecQ) repPragSpecInst (MkC ty) = rep2 pragSpecInstDName [ty] repPragComplete :: Core [TH.Name] -> Core (Maybe TH.Name) -> DsM (Core TH.DecQ) repPragComplete (MkC cls) (MkC mty) = rep2 pragCompleteDName [cls, mty] repPragRule :: Core String -> Core (Maybe [TH.TyVarBndrQ]) -> Core [TH.RuleBndrQ] -> Core TH.ExpQ -> Core TH.ExpQ -> Core TH.Phases -> DsM (Core TH.DecQ) repPragRule (MkC nm) (MkC ty_bndrs) (MkC tm_bndrs) (MkC lhs) (MkC rhs) (MkC phases) = rep2 pragRuleDName [nm, ty_bndrs, tm_bndrs, lhs, rhs, phases] repPragAnn :: Core TH.AnnTarget -> Core TH.ExpQ -> DsM (Core TH.DecQ) repPragAnn (MkC targ) (MkC e) = rep2 pragAnnDName [targ, e] repTySynInst :: Core TH.TySynEqnQ -> DsM (Core TH.DecQ) repTySynInst (MkC eqn) = rep2 tySynInstDName [eqn] repDataFamilyD :: Core TH.Name -> Core [TH.TyVarBndrQ] -> Core (Maybe TH.KindQ) -> DsM (Core TH.DecQ) repDataFamilyD (MkC nm) (MkC tvs) (MkC kind) = rep2 dataFamilyDName [nm, tvs, kind] repOpenFamilyD :: Core TH.Name -> Core [TH.TyVarBndrQ] -> Core TH.FamilyResultSigQ -> Core (Maybe TH.InjectivityAnn) -> DsM (Core TH.DecQ) repOpenFamilyD (MkC nm) (MkC tvs) (MkC result) (MkC inj) = rep2 openTypeFamilyDName [nm, tvs, result, inj] repClosedFamilyD :: Core TH.Name -> Core [TH.TyVarBndrQ] -> Core TH.FamilyResultSigQ -> Core (Maybe TH.InjectivityAnn) -> Core [TH.TySynEqnQ] -> DsM (Core TH.DecQ) repClosedFamilyD (MkC nm) (MkC tvs) (MkC res) (MkC inj) (MkC eqns) = rep2 closedTypeFamilyDName [nm, tvs, res, inj, eqns] repTySynEqn :: Core (Maybe [TH.TyVarBndrQ]) -> Core TH.TypeQ -> Core TH.TypeQ -> DsM (Core TH.TySynEqnQ) repTySynEqn (MkC mb_bndrs) (MkC lhs) (MkC rhs) = rep2 tySynEqnName [mb_bndrs, lhs, rhs] repRoleAnnotD :: Core TH.Name -> Core [TH.Role] -> DsM (Core TH.DecQ) repRoleAnnotD (MkC n) (MkC roles) = rep2 roleAnnotDName [n, roles] repFunDep :: Core [TH.Name] -> Core [TH.Name] -> DsM (Core TH.FunDep) repFunDep (MkC xs) (MkC ys) = rep2 funDepName [xs, ys] repProto :: Name -> Core TH.Name -> Core TH.TypeQ -> DsM (Core TH.DecQ) repProto mk_sig (MkC s) (MkC ty) = rep2 mk_sig [s, ty] repImplicitParamBind :: Core String -> Core TH.ExpQ -> DsM (Core TH.DecQ) repImplicitParamBind (MkC n) (MkC e) = rep2 implicitParamBindDName [n, e] repCtxt :: Core [TH.PredQ] -> DsM (Core TH.CxtQ) repCtxt (MkC tys) = rep2 cxtName [tys] repDataCon :: Located Name -> HsConDeclDetails GhcRn -> DsM (Core TH.ConQ) repDataCon con details = do con' <- lookupLOcc con -- See Note [Binders and occurrences] repConstr details Nothing [con'] repGadtDataCons :: [Located Name] -> HsConDeclDetails GhcRn -> LHsType GhcRn -> DsM (Core TH.ConQ) repGadtDataCons cons details res_ty = do cons' <- mapM lookupLOcc cons -- See Note [Binders and occurrences] repConstr details (Just res_ty) cons' -- Invariant: -- * for plain H98 data constructors second argument is Nothing and third -- argument is a singleton list -- * for GADTs data constructors second argument is (Just return_type) and -- third argument is a non-empty list repConstr :: HsConDeclDetails GhcRn -> Maybe (LHsType GhcRn) -> [Core TH.Name] -> DsM (Core TH.ConQ) repConstr (PrefixCon ps) Nothing [con] = do arg_tys <- repList bangTypeQTyConName repBangTy ps rep2 normalCName [unC con, unC arg_tys] repConstr (PrefixCon ps) (Just res_ty) cons = do arg_tys <- repList bangTypeQTyConName repBangTy ps res_ty' <- repLTy res_ty rep2 gadtCName [ unC (nonEmptyCoreList cons), unC arg_tys, unC res_ty'] repConstr (RecCon ips) resTy cons = do args <- concatMapM rep_ip (unLoc ips) arg_vtys <- coreList varBangTypeQTyConName args case resTy of Nothing -> rep2 recCName [unC (head cons), unC arg_vtys] Just res_ty -> do res_ty' <- repLTy res_ty rep2 recGadtCName [unC (nonEmptyCoreList cons), unC arg_vtys, unC res_ty'] where rep_ip (L _ ip) = mapM (rep_one_ip (cd_fld_type ip)) (cd_fld_names ip) rep_one_ip :: LBangType GhcRn -> LFieldOcc GhcRn -> DsM (Core a) rep_one_ip t n = do { MkC v <- lookupOcc (extFieldOcc $ unLoc n) ; MkC ty <- repBangTy t ; rep2 varBangTypeName [v,ty] } repConstr (InfixCon st1 st2) Nothing [con] = do arg1 <- repBangTy st1 arg2 <- repBangTy st2 rep2 infixCName [unC arg1, unC con, unC arg2] repConstr (InfixCon {}) (Just _) _ = panic "repConstr: infix GADT constructor should be in a PrefixCon" repConstr _ _ _ = panic "repConstr: invariant violated" ------------ Types ------------------- repTForall :: Core [TH.TyVarBndrQ] -> Core TH.CxtQ -> Core TH.TypeQ -> DsM (Core TH.TypeQ) repTForall (MkC tvars) (MkC ctxt) (MkC ty) = rep2 forallTName [tvars, ctxt, ty] repTForallVis :: Core [TH.TyVarBndrQ] -> Core TH.TypeQ -> DsM (Core TH.TypeQ) repTForallVis (MkC tvars) (MkC ty) = rep2 forallVisTName [tvars, ty] repTvar :: Core TH.Name -> DsM (Core TH.TypeQ) repTvar (MkC s) = rep2 varTName [s] repTapp :: Core TH.TypeQ -> Core TH.TypeQ -> DsM (Core TH.TypeQ) repTapp (MkC t1) (MkC t2) = rep2 appTName [t1, t2] repTappKind :: Core TH.TypeQ -> Core TH.KindQ -> DsM (Core TH.TypeQ) repTappKind (MkC ty) (MkC ki) = rep2 appKindTName [ty,ki] repTapps :: Core TH.TypeQ -> [Core TH.TypeQ] -> DsM (Core TH.TypeQ) repTapps f [] = return f repTapps f (t:ts) = do { f1 <- repTapp f t; repTapps f1 ts } repTSig :: Core TH.TypeQ -> Core TH.KindQ -> DsM (Core TH.TypeQ) repTSig (MkC ty) (MkC ki) = rep2 sigTName [ty, ki] repTequality :: DsM (Core TH.TypeQ) repTequality = rep2 equalityTName [] repTPromotedList :: [Core TH.TypeQ] -> DsM (Core TH.TypeQ) repTPromotedList [] = repPromotedNilTyCon repTPromotedList (t:ts) = do { tcon <- repPromotedConsTyCon ; f <- repTapp tcon t ; t' <- repTPromotedList ts ; repTapp f t' } repTLit :: Core TH.TyLitQ -> DsM (Core TH.TypeQ) repTLit (MkC lit) = rep2 litTName [lit] repTWildCard :: DsM (Core TH.TypeQ) repTWildCard = rep2 wildCardTName [] repTImplicitParam :: Core String -> Core TH.TypeQ -> DsM (Core TH.TypeQ) repTImplicitParam (MkC n) (MkC e) = rep2 implicitParamTName [n, e] repTStar :: DsM (Core TH.TypeQ) repTStar = rep2 starKName [] repTConstraint :: DsM (Core TH.TypeQ) repTConstraint = rep2 constraintKName [] --------- Type constructors -------------- repNamedTyCon :: Core TH.Name -> DsM (Core TH.TypeQ) repNamedTyCon (MkC s) = rep2 conTName [s] repTInfix :: Core TH.TypeQ -> Core TH.Name -> Core TH.TypeQ -> DsM (Core TH.TypeQ) repTInfix (MkC t1) (MkC name) (MkC t2) = rep2 infixTName [t1,name,t2] repTupleTyCon :: Int -> DsM (Core TH.TypeQ) -- Note: not Core Int; it's easier to be direct here repTupleTyCon i = do dflags <- getDynFlags rep2 tupleTName [mkIntExprInt dflags i] repUnboxedTupleTyCon :: Int -> DsM (Core TH.TypeQ) -- Note: not Core Int; it's easier to be direct here repUnboxedTupleTyCon i = do dflags <- getDynFlags rep2 unboxedTupleTName [mkIntExprInt dflags i] repUnboxedSumTyCon :: TH.SumArity -> DsM (Core TH.TypeQ) -- Note: not Core TH.SumArity; it's easier to be direct here repUnboxedSumTyCon arity = do dflags <- getDynFlags rep2 unboxedSumTName [mkIntExprInt dflags arity] repArrowTyCon :: DsM (Core TH.TypeQ) repArrowTyCon = rep2 arrowTName [] repListTyCon :: DsM (Core TH.TypeQ) repListTyCon = rep2 listTName [] repPromotedDataCon :: Core TH.Name -> DsM (Core TH.TypeQ) repPromotedDataCon (MkC s) = rep2 promotedTName [s] repPromotedTupleTyCon :: Int -> DsM (Core TH.TypeQ) repPromotedTupleTyCon i = do dflags <- getDynFlags rep2 promotedTupleTName [mkIntExprInt dflags i] repPromotedNilTyCon :: DsM (Core TH.TypeQ) repPromotedNilTyCon = rep2 promotedNilTName [] repPromotedConsTyCon :: DsM (Core TH.TypeQ) repPromotedConsTyCon = rep2 promotedConsTName [] ------------ TyVarBndrs ------------------- repPlainTV :: Core TH.Name -> DsM (Core TH.TyVarBndrQ) repPlainTV (MkC nm) = rep2 plainTVName [nm] repKindedTV :: Core TH.Name -> Core TH.KindQ -> DsM (Core TH.TyVarBndrQ) repKindedTV (MkC nm) (MkC ki) = rep2 kindedTVName [nm, ki] ---------------------------------------------------------- -- Type family result signature repNoSig :: DsM (Core TH.FamilyResultSigQ) repNoSig = rep2 noSigName [] repKindSig :: Core TH.KindQ -> DsM (Core TH.FamilyResultSigQ) repKindSig (MkC ki) = rep2 kindSigName [ki] repTyVarSig :: Core TH.TyVarBndrQ -> DsM (Core TH.FamilyResultSigQ) repTyVarSig (MkC bndr) = rep2 tyVarSigName [bndr] ---------------------------------------------------------- -- Literals repLiteral :: HsLit GhcRn -> DsM (Core TH.Lit) repLiteral (HsStringPrim _ bs) = do dflags <- getDynFlags word8_ty <- lookupType word8TyConName let w8s = unpack bs w8s_expr = map (\w8 -> mkCoreConApps word8DataCon [mkWordLit dflags (toInteger w8)]) w8s rep2 stringPrimLName [mkListExpr word8_ty w8s_expr] repLiteral lit = do lit' <- case lit of HsIntPrim _ i -> mk_integer i HsWordPrim _ w -> mk_integer w HsInt _ i -> mk_integer (il_value i) HsFloatPrim _ r -> mk_rational r HsDoublePrim _ r -> mk_rational r HsCharPrim _ c -> mk_char c _ -> return lit lit_expr <- dsLit lit' case mb_lit_name of Just lit_name -> rep2 lit_name [lit_expr] Nothing -> notHandled "Exotic literal" (ppr lit) where mb_lit_name = case lit of HsInteger _ _ _ -> Just integerLName HsInt _ _ -> Just integerLName HsIntPrim _ _ -> Just intPrimLName HsWordPrim _ _ -> Just wordPrimLName HsFloatPrim _ _ -> Just floatPrimLName HsDoublePrim _ _ -> Just doublePrimLName HsChar _ _ -> Just charLName HsCharPrim _ _ -> Just charPrimLName HsString _ _ -> Just stringLName HsRat _ _ _ -> Just rationalLName _ -> Nothing mk_integer :: Integer -> DsM (HsLit GhcRn) mk_integer i = do integer_ty <- lookupType integerTyConName return $ HsInteger NoSourceText i integer_ty mk_rational :: FractionalLit -> DsM (HsLit GhcRn) mk_rational r = do rat_ty <- lookupType rationalTyConName return $ HsRat noExtField r rat_ty mk_string :: FastString -> DsM (HsLit GhcRn) mk_string s = return $ HsString NoSourceText s mk_char :: Char -> DsM (HsLit GhcRn) mk_char c = return $ HsChar NoSourceText c repOverloadedLiteral :: HsOverLit GhcRn -> DsM (Core TH.Lit) repOverloadedLiteral (OverLit { ol_val = val}) = do { lit <- mk_lit val; repLiteral lit } -- The type Rational will be in the environment, because -- the smart constructor 'TH.Syntax.rationalL' uses it in its type, -- and rationalL is sucked in when any TH stuff is used repOverloadedLiteral (XOverLit nec) = noExtCon nec mk_lit :: OverLitVal -> DsM (HsLit GhcRn) mk_lit (HsIntegral i) = mk_integer (il_value i) mk_lit (HsFractional f) = mk_rational f mk_lit (HsIsString _ s) = mk_string s repNameS :: Core String -> DsM (Core TH.Name) repNameS (MkC name) = rep2 mkNameSName [name] --------------- Miscellaneous ------------------- repGensym :: Core String -> DsM (Core (TH.Q TH.Name)) repGensym (MkC lit_str) = rep2 newNameName [lit_str] repBindQ :: Type -> Type -- a and b -> Core (TH.Q a) -> Core (a -> TH.Q b) -> DsM (Core (TH.Q b)) repBindQ ty_a ty_b (MkC x) (MkC y) = rep2 bindQName [Type ty_a, Type ty_b, x, y] repSequenceQ :: Type -> Core [TH.Q a] -> DsM (Core (TH.Q [a])) repSequenceQ ty_a (MkC list) = rep2 sequenceQName [Type ty_a, list] repUnboundVar :: Core TH.Name -> DsM (Core TH.ExpQ) repUnboundVar (MkC name) = rep2 unboundVarEName [name] repOverLabel :: FastString -> DsM (Core TH.ExpQ) repOverLabel fs = do (MkC s) <- coreStringLit $ unpackFS fs rep2 labelEName [s] ------------ Lists ------------------- -- turn a list of patterns into a single pattern matching a list repList :: Name -> (a -> DsM (Core b)) -> [a] -> DsM (Core [b]) repList tc_name f args = do { args1 <- mapM f args ; coreList tc_name args1 } coreList :: Name -- Of the TyCon of the element type -> [Core a] -> DsM (Core [a]) coreList tc_name es = do { elt_ty <- lookupType tc_name; return (coreList' elt_ty es) } coreList' :: Type -- The element type -> [Core a] -> Core [a] coreList' elt_ty es = MkC (mkListExpr elt_ty (map unC es )) nonEmptyCoreList :: [Core a] -> Core [a] -- The list must be non-empty so we can get the element type -- Otherwise use coreList nonEmptyCoreList [] = panic "coreList: empty argument" nonEmptyCoreList xs@(MkC x:_) = MkC (mkListExpr (exprType x) (map unC xs)) coreStringLit :: String -> DsM (Core String) coreStringLit s = do { z <- mkStringExpr s; return(MkC z) } ------------------- Maybe ------------------ repMaybe :: Name -> (a -> DsM (Core b)) -> Maybe a -> DsM (Core (Maybe b)) repMaybe tc_name _ Nothing = coreNothing tc_name repMaybe tc_name f (Just es) = coreJust tc_name =<< f es -- | Construct Core expression for Nothing of a given type name coreNothing :: Name -- ^ Name of the TyCon of the element type -> DsM (Core (Maybe a)) coreNothing tc_name = do { elt_ty <- lookupType tc_name; return (coreNothing' elt_ty) } -- | Construct Core expression for Nothing of a given type coreNothing' :: Type -- ^ The element type -> Core (Maybe a) coreNothing' elt_ty = MkC (mkNothingExpr elt_ty) -- | Store given Core expression in a Just of a given type name coreJust :: Name -- ^ Name of the TyCon of the element type -> Core a -> DsM (Core (Maybe a)) coreJust tc_name es = do { elt_ty <- lookupType tc_name; return (coreJust' elt_ty es) } -- | Store given Core expression in a Just of a given type coreJust' :: Type -- ^ The element type -> Core a -> Core (Maybe a) coreJust' elt_ty es = MkC (mkJustExpr elt_ty (unC es)) ------------------- Maybe Lists ------------------ repMaybeList :: Name -> (a -> DsM (Core b)) -> Maybe [a] -> DsM (Core (Maybe [b])) repMaybeList tc_name _ Nothing = coreNothingList tc_name repMaybeList tc_name f (Just args) = do { elt_ty <- lookupType tc_name ; args1 <- mapM f args ; return $ coreJust' (mkListTy elt_ty) (coreList' elt_ty args1) } coreNothingList :: Name -> DsM (Core (Maybe [a])) coreNothingList tc_name = do { elt_ty <- lookupType tc_name ; return $ coreNothing' (mkListTy elt_ty) } coreJustList :: Name -> Core [a] -> DsM (Core (Maybe [a])) coreJustList tc_name args = do { elt_ty <- lookupType tc_name ; return $ coreJust' (mkListTy elt_ty) args } ------------ Literals & Variables ------------------- coreIntLit :: Int -> DsM (Core Int) coreIntLit i = do dflags <- getDynFlags return (MkC (mkIntExprInt dflags i)) coreIntegerLit :: Integer -> DsM (Core Integer) coreIntegerLit i = fmap MkC (mkIntegerExpr i) coreVar :: Id -> Core TH.Name -- The Id has type Name coreVar id = MkC (Var id) ----------------- Failure ----------------------- notHandledL :: SrcSpan -> String -> SDoc -> DsM a notHandledL loc what doc | isGoodSrcSpan loc = putSrcSpanDs loc $ notHandled what doc | otherwise = notHandled what doc notHandled :: String -> SDoc -> DsM a notHandled what doc = failWithDs msg where msg = hang (text what <+> text "not (yet) handled by Template Haskell") 2 doc