{-# LANGUAGE BangPatterns #-} {-# LANGUAGE ConstrainedClassMethods #-} {-# LANGUAGE DeriveFunctor #-} {-# LANGUAGE FlexibleContexts #-} {-# LANGUAGE FunctionalDependencies #-} {-# LANGUAGE LambdaCase #-} {-# LANGUAGE ScopedTypeVariables #-} {-# LANGUAGE TypeFamilies #-} {-# LANGUAGE ViewPatterns #-} {-# OPTIONS_GHC -Wno-incomplete-record-updates #-} {-# OPTIONS_GHC -Wno-incomplete-uni-patterns #-} {- (c) The University of Glasgow 2006 (c) The GRASP/AQUA Project, Glasgow University, 1992-1998 This module converts Template Haskell syntax into Hs syntax -} module GHC.ThToHs ( convertToHsExpr , convertToPat , convertToHsDecls , convertToHsType , thRdrNameGuesses ) where import GHC.Prelude import GHC.Hs as Hs import GHC.Builtin.Names import GHC.Types.Name.Reader import qualified GHC.Types.Name as Name import GHC.Unit.Module import GHC.Parser.PostProcess import GHC.Types.Name.Occurrence as OccName import GHC.Types.SrcLoc import GHC.Core.Type as Hs import qualified GHC.Core.Coercion as Coercion ( Role(..) ) import GHC.Builtin.Types import GHC.Types.Basic as Hs import GHC.Types.Fixity as Hs import GHC.Types.ForeignCall import GHC.Types.Unique import GHC.Types.SourceText import GHC.Utils.Error import GHC.Data.Bag import GHC.Utils.Lexeme import GHC.Utils.Misc import GHC.Data.FastString import GHC.Utils.Outputable as Outputable import GHC.Utils.Panic import qualified Data.ByteString as BS import Control.Monad( unless, ap ) import Data.Maybe( catMaybes, isNothing ) import Language.Haskell.TH as TH hiding (sigP) import Language.Haskell.TH.Syntax as TH import Foreign.ForeignPtr import Foreign.Ptr import System.IO.Unsafe ------------------------------------------------------------------- -- The external interface convertToHsDecls :: Origin -> SrcSpan -> [TH.Dec] -> Either SDoc [LHsDecl GhcPs] convertToHsDecls origin loc ds = initCvt origin loc (fmap catMaybes (mapM cvt_dec ds)) where cvt_dec d = wrapMsg "declaration" d (cvtDec d) convertToHsExpr :: Origin -> SrcSpan -> TH.Exp -> Either SDoc (LHsExpr GhcPs) convertToHsExpr origin loc e = initCvt origin loc $ wrapMsg "expression" e $ cvtl e convertToPat :: Origin -> SrcSpan -> TH.Pat -> Either SDoc (LPat GhcPs) convertToPat origin loc p = initCvt origin loc $ wrapMsg "pattern" p $ cvtPat p convertToHsType :: Origin -> SrcSpan -> TH.Type -> Either SDoc (LHsType GhcPs) convertToHsType origin loc t = initCvt origin loc $ wrapMsg "type" t $ cvtType t ------------------------------------------------------------------- newtype CvtM a = CvtM { unCvtM :: Origin -> SrcSpan -> Either SDoc (SrcSpan, a) } deriving (Functor) -- Push down the Origin (that is configurable by -- -fenable-th-splice-warnings) and source location; -- Can fail, with a single error message -- NB: If the conversion succeeds with (Right x), there should -- be no exception values hiding in x -- Reason: so a (head []) in TH code doesn't subsequently -- make GHC crash when it tries to walk the generated tree -- Use the loc everywhere, for lack of anything better -- In particular, we want it on binding locations, so that variables bound in -- the spliced-in declarations get a location that at least relates to the splice point instance Applicative CvtM where pure x = CvtM $ \_ loc -> Right (loc,x) (<*>) = ap instance Monad CvtM where (CvtM m) >>= k = CvtM $ \origin loc -> case m origin loc of Left err -> Left err Right (loc',v) -> unCvtM (k v) origin loc' initCvt :: Origin -> SrcSpan -> CvtM a -> Either SDoc a initCvt origin loc (CvtM m) = fmap snd (m origin loc) force :: a -> CvtM () force a = a `seq` return () failWith :: SDoc -> CvtM a failWith m = CvtM (\_ _ -> Left m) getOrigin :: CvtM Origin getOrigin = CvtM (\origin loc -> Right (loc,origin)) getL :: CvtM SrcSpan getL = CvtM (\_ loc -> Right (loc,loc)) setL :: SrcSpan -> CvtM () setL loc = CvtM (\_ _ -> Right (loc, ())) returnLA :: e -> CvtM (GenLocated (SrcSpanAnn' (EpAnn ann)) e) returnLA x = CvtM (\_ loc -> Right (loc, L (noAnnSrcSpan loc) x)) returnJustLA :: a -> CvtM (Maybe (LocatedA a)) returnJustLA = fmap Just . returnLA wrapParLA :: (LocatedA a -> a) -> a -> CvtM a wrapParLA add_par x = CvtM (\_ loc -> Right (loc, add_par (L (noAnnSrcSpan loc) x))) wrapMsg :: (Show a, TH.Ppr a) => String -> a -> CvtM b -> CvtM b -- E.g wrapMsg "declaration" dec thing wrapMsg what item (CvtM m) = CvtM $ \origin loc -> case m origin loc of Left err -> Left (err $$ msg) Right v -> Right v where -- Show the item in pretty syntax normally, -- but with all its constructors if you say -dppr-debug msg = hang (text "When splicing a TH" <+> text what <> colon) 2 (getPprDebug $ \case True -> text (show item) False -> text (pprint item)) wrapL :: CvtM a -> CvtM (Located a) wrapL (CvtM m) = CvtM $ \origin loc -> case m origin loc of Left err -> Left err Right (loc', v) -> Right (loc', L loc v) wrapLN :: CvtM a -> CvtM (LocatedN a) wrapLN (CvtM m) = CvtM $ \origin loc -> case m origin loc of Left err -> Left err Right (loc', v) -> Right (loc', L (noAnnSrcSpan loc) v) wrapLA :: CvtM a -> CvtM (LocatedA a) wrapLA (CvtM m) = CvtM $ \origin loc -> case m origin loc of Left err -> Left err Right (loc', v) -> Right (loc', L (noAnnSrcSpan loc) v) ------------------------------------------------------------------- cvtDecs :: [TH.Dec] -> CvtM [LHsDecl GhcPs] cvtDecs = fmap catMaybes . mapM cvtDec cvtDec :: TH.Dec -> CvtM (Maybe (LHsDecl GhcPs)) cvtDec (TH.ValD pat body ds) | TH.VarP s <- pat = do { s' <- vNameN s ; cl' <- cvtClause (mkPrefixFunRhs s') (Clause [] body ds) ; th_origin <- getOrigin ; returnJustLA $ Hs.ValD noExtField $ mkFunBind th_origin s' [cl'] } | otherwise = do { pat' <- cvtPat pat ; body' <- cvtGuard body ; ds' <- cvtLocalDecs (text "a where clause") ds ; returnJustLA $ Hs.ValD noExtField $ PatBind { pat_lhs = pat' , pat_rhs = GRHSs emptyComments body' ds' , pat_ext = noAnn , pat_ticks = ([],[]) } } cvtDec (TH.FunD nm cls) | null cls = failWith (text "Function binding for" <+> quotes (text (TH.pprint nm)) <+> text "has no equations") | otherwise = do { nm' <- vNameN nm ; cls' <- mapM (cvtClause (mkPrefixFunRhs nm')) cls ; th_origin <- getOrigin ; returnJustLA $ Hs.ValD noExtField $ mkFunBind th_origin nm' cls' } cvtDec (TH.SigD nm typ) = do { nm' <- vNameN nm ; ty' <- cvtSigType typ ; returnJustLA $ Hs.SigD noExtField (TypeSig noAnn [nm'] (mkHsWildCardBndrs ty')) } cvtDec (TH.KiSigD nm ki) = do { nm' <- tconNameN nm ; ki' <- cvtSigKind ki ; let sig' = StandaloneKindSig noAnn nm' ki' ; returnJustLA $ Hs.KindSigD noExtField sig' } cvtDec (TH.InfixD fx nm) -- Fixity signatures are allowed for variables, constructors, and types -- the renamer automatically looks for types during renaming, even when -- the RdrName says it's a variable or a constructor. So, just assume -- it's a variable or constructor and proceed. = do { nm' <- vcNameN nm ; returnJustLA (Hs.SigD noExtField (FixSig noAnn (FixitySig noExtField [nm'] (cvtFixity fx)))) } cvtDec (TH.DefaultD tys) = do { tys' <- traverse cvtType tys ; returnJustLA (Hs.DefD noExtField $ DefaultDecl noAnn tys') } cvtDec (PragmaD prag) = cvtPragmaD prag cvtDec (TySynD tc tvs rhs) = do { (_, tc', tvs') <- cvt_tycl_hdr [] tc tvs ; rhs' <- cvtType rhs ; returnJustLA $ TyClD noExtField $ SynDecl { tcdSExt = noAnn, tcdLName = tc', tcdTyVars = tvs' , tcdFixity = Prefix , tcdRhs = rhs' } } cvtDec (DataD ctxt tc tvs ksig constrs derivs) = do { let isGadtCon (GadtC _ _ _) = True isGadtCon (RecGadtC _ _ _) = True isGadtCon (ForallC _ _ c) = isGadtCon c isGadtCon _ = False isGadtDecl = all isGadtCon constrs isH98Decl = all (not . isGadtCon) constrs ; unless (isGadtDecl || isH98Decl) (failWith (text "Cannot mix GADT constructors with Haskell 98" <+> text "constructors")) ; unless (isNothing ksig || isGadtDecl) (failWith (text "Kind signatures are only allowed on GADTs")) ; (ctxt', tc', tvs') <- cvt_tycl_hdr ctxt tc tvs ; ksig' <- cvtKind `traverse` ksig ; cons' <- mapM cvtConstr constrs ; derivs' <- cvtDerivs derivs ; let defn = HsDataDefn { dd_ext = noExtField , dd_ND = DataType, dd_cType = Nothing , dd_ctxt = mkHsContextMaybe ctxt' , dd_kindSig = ksig' , dd_cons = cons', dd_derivs = derivs' } ; returnJustLA $ TyClD noExtField $ DataDecl { tcdDExt = noAnn , tcdLName = tc', tcdTyVars = tvs' , tcdFixity = Prefix , tcdDataDefn = defn } } cvtDec (NewtypeD ctxt tc tvs ksig constr derivs) = do { (ctxt', tc', tvs') <- cvt_tycl_hdr ctxt tc tvs ; ksig' <- cvtKind `traverse` ksig ; con' <- cvtConstr constr ; derivs' <- cvtDerivs derivs ; let defn = HsDataDefn { dd_ext = noExtField , dd_ND = NewType, dd_cType = Nothing , dd_ctxt = mkHsContextMaybe ctxt' , dd_kindSig = ksig' , dd_cons = [con'] , dd_derivs = derivs' } ; returnJustLA $ TyClD noExtField $ DataDecl { tcdDExt = noAnn , tcdLName = tc', tcdTyVars = tvs' , tcdFixity = Prefix , tcdDataDefn = defn } } cvtDec (ClassD ctxt cl tvs fds decs) = do { (cxt', tc', tvs') <- cvt_tycl_hdr ctxt cl tvs ; fds' <- mapM cvt_fundep fds ; (binds', sigs', fams', at_defs', adts') <- cvt_ci_decs (text "a class declaration") decs ; unless (null adts') (failWith $ (text "Default data instance declarations" <+> text "are not allowed:") $$ (Outputable.ppr adts')) ; returnJustLA $ TyClD noExtField $ ClassDecl { tcdCExt = (noAnn, NoAnnSortKey, NoLayoutInfo) , tcdCtxt = mkHsContextMaybe cxt', tcdLName = tc', tcdTyVars = tvs' , tcdFixity = Prefix , tcdFDs = fds', tcdSigs = Hs.mkClassOpSigs sigs' , tcdMeths = binds' , tcdATs = fams', tcdATDefs = at_defs', tcdDocs = [] } -- no docs in TH ^^ } cvtDec (InstanceD o ctxt ty decs) = do { let doc = text "an instance declaration" ; (binds', sigs', fams', ats', adts') <- cvt_ci_decs doc decs ; unless (null fams') (failWith (mkBadDecMsg doc fams')) ; ctxt' <- cvtContext funPrec ctxt ; (L loc ty') <- cvtType ty ; let inst_ty' = L loc $ mkHsImplicitSigType $ mkHsQualTy ctxt loc ctxt' $ L loc ty' ; returnJustLA $ InstD noExtField $ ClsInstD noExtField $ ClsInstDecl { cid_ext = (noAnn, NoAnnSortKey), cid_poly_ty = inst_ty' , cid_binds = binds' , cid_sigs = Hs.mkClassOpSigs sigs' , cid_tyfam_insts = ats', cid_datafam_insts = adts' , cid_overlap_mode = fmap (L (l2l loc) . overlap) o } } where overlap pragma = case pragma of TH.Overlaps -> Hs.Overlaps (SourceText "OVERLAPS") TH.Overlappable -> Hs.Overlappable (SourceText "OVERLAPPABLE") TH.Overlapping -> Hs.Overlapping (SourceText "OVERLAPPING") TH.Incoherent -> Hs.Incoherent (SourceText "INCOHERENT") cvtDec (ForeignD ford) = do { ford' <- cvtForD ford ; returnJustLA $ ForD noExtField ford' } cvtDec (DataFamilyD tc tvs kind) = do { (_, tc', tvs') <- cvt_tycl_hdr [] tc tvs ; result <- cvtMaybeKindToFamilyResultSig kind ; returnJustLA $ TyClD noExtField $ FamDecl noExtField $ FamilyDecl noAnn DataFamily TopLevel tc' tvs' Prefix result Nothing } cvtDec (DataInstD ctxt bndrs tys ksig constrs derivs) = do { (ctxt', tc', bndrs', typats') <- cvt_datainst_hdr ctxt bndrs tys ; ksig' <- cvtKind `traverse` ksig ; cons' <- mapM cvtConstr constrs ; derivs' <- cvtDerivs derivs ; let defn = HsDataDefn { dd_ext = noExtField , dd_ND = DataType, dd_cType = Nothing , dd_ctxt = mkHsContextMaybe ctxt' , dd_kindSig = ksig' , dd_cons = cons', dd_derivs = derivs' } ; returnJustLA $ InstD noExtField $ DataFamInstD { dfid_ext = noAnn , dfid_inst = DataFamInstDecl { dfid_eqn = FamEqn { feqn_ext = noAnn , feqn_tycon = tc' , feqn_bndrs = bndrs' , feqn_pats = typats' , feqn_rhs = defn , feqn_fixity = Prefix } }}} cvtDec (NewtypeInstD ctxt bndrs tys ksig constr derivs) = do { (ctxt', tc', bndrs', typats') <- cvt_datainst_hdr ctxt bndrs tys ; ksig' <- cvtKind `traverse` ksig ; con' <- cvtConstr constr ; derivs' <- cvtDerivs derivs ; let defn = HsDataDefn { dd_ext = noExtField , dd_ND = NewType, dd_cType = Nothing , dd_ctxt = mkHsContextMaybe ctxt' , dd_kindSig = ksig' , dd_cons = [con'], dd_derivs = derivs' } ; returnJustLA $ InstD noExtField $ DataFamInstD { dfid_ext = noAnn , dfid_inst = DataFamInstDecl { dfid_eqn = FamEqn { feqn_ext = noAnn , feqn_tycon = tc' , feqn_bndrs = bndrs' , feqn_pats = typats' , feqn_rhs = defn , feqn_fixity = Prefix } }}} cvtDec (TySynInstD eqn) = do { (L _ eqn') <- cvtTySynEqn eqn ; returnJustLA $ InstD noExtField $ TyFamInstD { tfid_ext = noExtField , tfid_inst = TyFamInstDecl { tfid_xtn = noAnn, tfid_eqn = eqn' } }} cvtDec (OpenTypeFamilyD head) = do { (tc', tyvars', result', injectivity') <- cvt_tyfam_head head ; returnJustLA $ TyClD noExtField $ FamDecl noExtField $ FamilyDecl noAnn OpenTypeFamily TopLevel tc' tyvars' Prefix result' injectivity' } cvtDec (ClosedTypeFamilyD head eqns) = do { (tc', tyvars', result', injectivity') <- cvt_tyfam_head head ; eqns' <- mapM cvtTySynEqn eqns ; returnJustLA $ TyClD noExtField $ FamDecl noExtField $ FamilyDecl noAnn (ClosedTypeFamily (Just eqns')) TopLevel tc' tyvars' Prefix result' injectivity' } cvtDec (TH.RoleAnnotD tc roles) = do { tc' <- tconNameN tc ; let roles' = map (noLocA . cvtRole) roles ; returnJustLA $ Hs.RoleAnnotD noExtField (RoleAnnotDecl noAnn tc' roles') } cvtDec (TH.StandaloneDerivD ds cxt ty) = do { cxt' <- cvtContext funPrec cxt ; ds' <- traverse cvtDerivStrategy ds ; (L loc ty') <- cvtType ty ; let inst_ty' = L loc $ mkHsImplicitSigType $ mkHsQualTy cxt loc cxt' $ L loc ty' ; returnJustLA $ DerivD noExtField $ DerivDecl { deriv_ext = noAnn , deriv_strategy = ds' , deriv_type = mkHsWildCardBndrs inst_ty' , deriv_overlap_mode = Nothing } } cvtDec (TH.DefaultSigD nm typ) = do { nm' <- vNameN nm ; ty' <- cvtSigType typ ; returnJustLA $ Hs.SigD noExtField $ ClassOpSig noAnn True [nm'] ty'} cvtDec (TH.PatSynD nm args dir pat) = do { nm' <- cNameN nm ; args' <- cvtArgs args ; dir' <- cvtDir nm' dir ; pat' <- cvtPat pat ; returnJustLA $ Hs.ValD noExtField $ PatSynBind noExtField $ PSB noAnn nm' args' pat' dir' } where cvtArgs (TH.PrefixPatSyn args) = Hs.PrefixCon noTypeArgs <$> mapM vNameN args cvtArgs (TH.InfixPatSyn a1 a2) = Hs.InfixCon <$> vNameN a1 <*> vNameN a2 cvtArgs (TH.RecordPatSyn sels) = do { sels' <- mapM (fmap (\ (L li i) -> FieldOcc noExtField (L li i)) . vNameN) sels ; vars' <- mapM (vNameN . mkNameS . nameBase) sels ; return $ Hs.RecCon $ zipWith RecordPatSynField sels' vars' } -- cvtDir :: LocatedN RdrName -> (PatSynDir -> CvtM (HsPatSynDir RdrName)) cvtDir _ Unidir = return Unidirectional cvtDir _ ImplBidir = return ImplicitBidirectional cvtDir n (ExplBidir cls) = do { ms <- mapM (cvtClause (mkPrefixFunRhs n)) cls ; th_origin <- getOrigin ; return $ ExplicitBidirectional $ mkMatchGroup th_origin (noLocA ms) } cvtDec (TH.PatSynSigD nm ty) = do { nm' <- cNameN nm ; ty' <- cvtPatSynSigTy ty ; returnJustLA $ Hs.SigD noExtField $ PatSynSig noAnn [nm'] ty'} -- Implicit parameter bindings are handled in cvtLocalDecs and -- cvtImplicitParamBind. They are not allowed in any other scope, so -- reaching this case indicates an error. cvtDec (TH.ImplicitParamBindD _ _) = failWith (text "Implicit parameter binding only allowed in let or where") ---------------- cvtTySynEqn :: TySynEqn -> CvtM (LTyFamInstEqn GhcPs) cvtTySynEqn (TySynEqn mb_bndrs lhs rhs) = do { mb_bndrs' <- traverse (mapM cvt_tv) mb_bndrs ; let outer_bndrs = mkHsOuterFamEqnTyVarBndrs mb_bndrs' ; (head_ty, args) <- split_ty_app lhs ; case head_ty of ConT nm -> do { nm' <- tconNameN nm ; rhs' <- cvtType rhs ; let args' = map wrap_tyarg args ; returnLA $ FamEqn { feqn_ext = noAnn , feqn_tycon = nm' , feqn_bndrs = outer_bndrs , feqn_pats = args' , feqn_fixity = Prefix , feqn_rhs = rhs' } } InfixT t1 nm t2 -> do { nm' <- tconNameN nm ; args' <- mapM cvtType [t1,t2] ; rhs' <- cvtType rhs ; returnLA $ FamEqn { feqn_ext = noAnn , feqn_tycon = nm' , feqn_bndrs = outer_bndrs , feqn_pats = (map HsValArg args') ++ args , feqn_fixity = Hs.Infix , feqn_rhs = rhs' } } _ -> failWith $ text "Invalid type family instance LHS:" <+> text (show lhs) } ---------------- cvt_ci_decs :: SDoc -> [TH.Dec] -> CvtM (LHsBinds GhcPs, [LSig GhcPs], [LFamilyDecl GhcPs], [LTyFamInstDecl GhcPs], [LDataFamInstDecl GhcPs]) -- Convert the declarations inside a class or instance decl -- ie signatures, bindings, and associated types cvt_ci_decs doc decs = do { decs' <- cvtDecs decs ; let (ats', bind_sig_decs') = partitionWith is_tyfam_inst decs' ; let (adts', no_ats') = partitionWith is_datafam_inst bind_sig_decs' ; let (sigs', prob_binds') = partitionWith is_sig no_ats' ; let (binds', prob_fams') = partitionWith is_bind prob_binds' ; let (fams', bads) = partitionWith is_fam_decl prob_fams' ; unless (null bads) (failWith (mkBadDecMsg doc bads)) ; return (listToBag binds', sigs', fams', ats', adts') } ---------------- cvt_tycl_hdr :: TH.Cxt -> TH.Name -> [TH.TyVarBndr ()] -> CvtM ( LHsContext GhcPs , LocatedN RdrName , LHsQTyVars GhcPs) cvt_tycl_hdr cxt tc tvs = do { cxt' <- cvtContext funPrec cxt ; tc' <- tconNameN tc ; tvs' <- cvtTvs tvs ; return (cxt', tc', mkHsQTvs tvs') } cvt_datainst_hdr :: TH.Cxt -> Maybe [TH.TyVarBndr ()] -> TH.Type -> CvtM ( LHsContext GhcPs , LocatedN RdrName , HsOuterFamEqnTyVarBndrs GhcPs , HsTyPats GhcPs) cvt_datainst_hdr cxt bndrs tys = do { cxt' <- cvtContext funPrec cxt ; bndrs' <- traverse (mapM cvt_tv) bndrs ; let outer_bndrs = mkHsOuterFamEqnTyVarBndrs bndrs' ; (head_ty, args) <- split_ty_app tys ; case head_ty of ConT nm -> do { nm' <- tconNameN nm ; let args' = map wrap_tyarg args ; return (cxt', nm', outer_bndrs, args') } InfixT t1 nm t2 -> do { nm' <- tconNameN nm ; args' <- mapM cvtType [t1,t2] ; return (cxt', nm', outer_bndrs, ((map HsValArg args') ++ args)) } _ -> failWith $ text "Invalid type instance header:" <+> text (show tys) } ---------------- cvt_tyfam_head :: TypeFamilyHead -> CvtM ( LocatedN RdrName , LHsQTyVars GhcPs , Hs.LFamilyResultSig GhcPs , Maybe (Hs.LInjectivityAnn GhcPs)) cvt_tyfam_head (TypeFamilyHead tc tyvars result injectivity) = do {(_, tc', tyvars') <- cvt_tycl_hdr [] tc tyvars ; result' <- cvtFamilyResultSig result ; injectivity' <- traverse cvtInjectivityAnnotation injectivity ; return (tc', tyvars', result', injectivity') } ------------------------------------------------------------------- -- Partitioning declarations ------------------------------------------------------------------- is_fam_decl :: LHsDecl GhcPs -> Either (LFamilyDecl GhcPs) (LHsDecl GhcPs) is_fam_decl (L loc (TyClD _ (FamDecl { tcdFam = d }))) = Left (L loc d) is_fam_decl decl = Right decl is_tyfam_inst :: LHsDecl GhcPs -> Either (LTyFamInstDecl GhcPs) (LHsDecl GhcPs) is_tyfam_inst (L loc (Hs.InstD _ (TyFamInstD { tfid_inst = d }))) = Left (L loc d) is_tyfam_inst decl = Right decl is_datafam_inst :: LHsDecl GhcPs -> Either (LDataFamInstDecl GhcPs) (LHsDecl GhcPs) is_datafam_inst (L loc (Hs.InstD _ (DataFamInstD { dfid_inst = d }))) = Left (L loc d) is_datafam_inst decl = Right decl is_sig :: LHsDecl GhcPs -> Either (LSig GhcPs) (LHsDecl GhcPs) is_sig (L loc (Hs.SigD _ sig)) = Left (L loc sig) is_sig decl = Right decl is_bind :: LHsDecl GhcPs -> Either (LHsBind GhcPs) (LHsDecl GhcPs) is_bind (L loc (Hs.ValD _ bind)) = Left (L loc bind) is_bind decl = Right decl is_ip_bind :: TH.Dec -> Either (String, TH.Exp) TH.Dec is_ip_bind (TH.ImplicitParamBindD n e) = Left (n, e) is_ip_bind decl = Right decl mkBadDecMsg :: Outputable a => SDoc -> [a] -> SDoc mkBadDecMsg doc bads = sep [ text "Illegal declaration(s) in" <+> doc <> colon , nest 2 (vcat (map Outputable.ppr bads)) ] --------------------------------------------------- -- Data types --------------------------------------------------- cvtConstr :: TH.Con -> CvtM (LConDecl GhcPs) cvtConstr (NormalC c strtys) = do { c' <- cNameN c ; tys' <- mapM cvt_arg strtys ; returnLA $ mkConDeclH98 noAnn c' Nothing Nothing (PrefixCon noTypeArgs (map hsLinear tys')) } cvtConstr (RecC c varstrtys) = do { c' <- cNameN c ; args' <- mapM cvt_id_arg varstrtys ; returnLA $ mkConDeclH98 noAnn c' Nothing Nothing (RecCon (noLocA args')) } cvtConstr (InfixC st1 c st2) = do { c' <- cNameN c ; st1' <- cvt_arg st1 ; st2' <- cvt_arg st2 ; returnLA $ mkConDeclH98 noAnn c' Nothing Nothing (InfixCon (hsLinear st1') (hsLinear st2')) } cvtConstr (ForallC tvs ctxt con) = do { tvs' <- cvtTvs tvs ; ctxt' <- cvtContext funPrec ctxt ; L _ con' <- cvtConstr con ; returnLA $ add_forall tvs' ctxt' con' } where add_cxt lcxt Nothing = mkHsContextMaybe lcxt add_cxt (L loc cxt1) (Just (L _ cxt2)) = Just (L loc (cxt1 ++ cxt2)) add_forall :: [LHsTyVarBndr Hs.Specificity GhcPs] -> LHsContext GhcPs -> ConDecl GhcPs -> ConDecl GhcPs add_forall tvs' cxt' con@(ConDeclGADT { con_bndrs = L l outer_bndrs, con_mb_cxt = cxt }) = con { con_bndrs = L l outer_bndrs' , con_mb_cxt = add_cxt cxt' cxt } where outer_bndrs' | null all_tvs = mkHsOuterImplicit | otherwise = mkHsOuterExplicit noAnn all_tvs all_tvs = tvs' ++ outer_exp_tvs outer_exp_tvs = hsOuterExplicitBndrs outer_bndrs add_forall tvs' cxt' con@(ConDeclH98 { con_ex_tvs = ex_tvs, con_mb_cxt = cxt }) = con { con_forall = not (null all_tvs) , con_ex_tvs = all_tvs , con_mb_cxt = add_cxt cxt' cxt } where all_tvs = tvs' ++ ex_tvs cvtConstr (GadtC [] _strtys _ty) = failWith (text "GadtC must have at least one constructor name") cvtConstr (GadtC c strtys ty) = do { c' <- mapM cNameN c ; args <- mapM cvt_arg strtys ; ty' <- cvtType ty ; returnLA $ mk_gadt_decl c' (PrefixConGADT $ map hsLinear args) ty'} cvtConstr (RecGadtC [] _varstrtys _ty) = failWith (text "RecGadtC must have at least one constructor name") cvtConstr (RecGadtC c varstrtys ty) = do { c' <- mapM cNameN c ; ty' <- cvtType ty ; rec_flds <- mapM cvt_id_arg varstrtys ; returnLA $ mk_gadt_decl c' (RecConGADT (noLocA rec_flds) noHsUniTok) ty' } mk_gadt_decl :: [LocatedN RdrName] -> HsConDeclGADTDetails GhcPs -> LHsType GhcPs -> ConDecl GhcPs mk_gadt_decl names args res_ty = ConDeclGADT { con_g_ext = noAnn , con_names = names , con_bndrs = noLocA mkHsOuterImplicit , con_mb_cxt = Nothing , con_g_args = args , con_res_ty = res_ty , con_doc = Nothing } cvtSrcUnpackedness :: TH.SourceUnpackedness -> SrcUnpackedness cvtSrcUnpackedness NoSourceUnpackedness = NoSrcUnpack cvtSrcUnpackedness SourceNoUnpack = SrcNoUnpack cvtSrcUnpackedness SourceUnpack = SrcUnpack cvtSrcStrictness :: TH.SourceStrictness -> SrcStrictness cvtSrcStrictness NoSourceStrictness = NoSrcStrict cvtSrcStrictness SourceLazy = SrcLazy cvtSrcStrictness SourceStrict = SrcStrict cvt_arg :: (TH.Bang, TH.Type) -> CvtM (LHsType GhcPs) cvt_arg (Bang su ss, ty) = do { ty'' <- cvtType ty ; let ty' = parenthesizeHsType appPrec ty'' su' = cvtSrcUnpackedness su ss' = cvtSrcStrictness ss ; returnLA $ HsBangTy noAnn (HsSrcBang NoSourceText su' ss') ty' } cvt_id_arg :: (TH.Name, TH.Bang, TH.Type) -> CvtM (LConDeclField GhcPs) cvt_id_arg (i, str, ty) = do { L li i' <- vNameN i ; ty' <- cvt_arg (str,ty) ; return $ noLocA (ConDeclField { cd_fld_ext = noAnn , cd_fld_names = [L (l2l li) $ FieldOcc noExtField (L li i')] , cd_fld_type = ty' , cd_fld_doc = Nothing}) } cvtDerivs :: [TH.DerivClause] -> CvtM (HsDeriving GhcPs) cvtDerivs cs = do { mapM cvtDerivClause cs } cvt_fundep :: TH.FunDep -> CvtM (LHsFunDep GhcPs) cvt_fundep (TH.FunDep xs ys) = do { xs' <- mapM tNameN xs ; ys' <- mapM tNameN ys ; returnLA (Hs.FunDep noAnn xs' ys') } ------------------------------------------ -- Foreign declarations ------------------------------------------ cvtForD :: Foreign -> CvtM (ForeignDecl GhcPs) cvtForD (ImportF callconv safety from nm ty) -- the prim and javascript calling conventions do not support headers -- and are inserted verbatim, analogous to mkImport in GHC.Parser.PostProcess | callconv == TH.Prim || callconv == TH.JavaScript = mk_imp (CImport (noLoc (cvt_conv callconv)) (noLoc safety') Nothing (CFunction (StaticTarget (SourceText from) (mkFastString from) Nothing True)) (noLoc $ quotedSourceText from)) | Just impspec <- parseCImport (noLoc (cvt_conv callconv)) (noLoc safety') (mkFastString (TH.nameBase nm)) from (noLoc $ quotedSourceText from) = mk_imp impspec | otherwise = failWith $ text (show from) <+> text "is not a valid ccall impent" where mk_imp impspec = do { nm' <- vNameN nm ; ty' <- cvtSigType ty ; return (ForeignImport { fd_i_ext = noAnn , fd_name = nm' , fd_sig_ty = ty' , fd_fi = impspec }) } safety' = case safety of Unsafe -> PlayRisky Safe -> PlaySafe Interruptible -> PlayInterruptible cvtForD (ExportF callconv as nm ty) = do { nm' <- vNameN nm ; ty' <- cvtSigType ty ; let e = CExport (noLoc (CExportStatic (SourceText as) (mkFastString as) (cvt_conv callconv))) (noLoc (SourceText as)) ; return $ ForeignExport { fd_e_ext = noAnn , fd_name = nm' , fd_sig_ty = ty' , fd_fe = e } } cvt_conv :: TH.Callconv -> CCallConv cvt_conv TH.CCall = CCallConv cvt_conv TH.StdCall = StdCallConv cvt_conv TH.CApi = CApiConv cvt_conv TH.Prim = PrimCallConv cvt_conv TH.JavaScript = JavaScriptCallConv ------------------------------------------ -- Pragmas ------------------------------------------ cvtPragmaD :: Pragma -> CvtM (Maybe (LHsDecl GhcPs)) cvtPragmaD (InlineP nm inline rm phases) = do { nm' <- vNameN nm ; let dflt = dfltActivation inline ; let src TH.NoInline = "{-# NOINLINE" src TH.Inline = "{-# INLINE" src TH.Inlinable = "{-# INLINABLE" ; let ip = InlinePragma { inl_src = toSrcTxt inline , inl_inline = cvtInline inline (toSrcTxt inline) , inl_rule = cvtRuleMatch rm , inl_act = cvtPhases phases dflt , inl_sat = Nothing } where toSrcTxt a = SourceText $ src a ; returnJustLA $ Hs.SigD noExtField $ InlineSig noAnn nm' ip } cvtPragmaD (SpecialiseP nm ty inline phases) = do { nm' <- vNameN nm ; ty' <- cvtSigType ty ; let src TH.NoInline = "{-# SPECIALISE NOINLINE" src TH.Inline = "{-# SPECIALISE INLINE" src TH.Inlinable = "{-# SPECIALISE INLINE" ; let (inline', dflt, srcText) = case inline of Just inline1 -> (cvtInline inline1 (toSrcTxt inline1), dfltActivation inline1, toSrcTxt inline1) Nothing -> (NoUserInlinePrag, AlwaysActive, SourceText "{-# SPECIALISE") where toSrcTxt a = SourceText $ src a ; let ip = InlinePragma { inl_src = srcText , inl_inline = inline' , inl_rule = Hs.FunLike , inl_act = cvtPhases phases dflt , inl_sat = Nothing } ; returnJustLA $ Hs.SigD noExtField $ SpecSig noAnn nm' [ty'] ip } cvtPragmaD (SpecialiseInstP ty) = do { ty' <- cvtSigType ty ; returnJustLA $ Hs.SigD noExtField $ SpecInstSig noAnn (SourceText "{-# SPECIALISE") ty' } cvtPragmaD (RuleP nm ty_bndrs tm_bndrs lhs rhs phases) = do { let nm' = mkFastString nm ; let act = cvtPhases phases AlwaysActive ; ty_bndrs' <- traverse cvtTvs ty_bndrs ; tm_bndrs' <- mapM cvtRuleBndr tm_bndrs ; lhs' <- cvtl lhs ; rhs' <- cvtl rhs ; returnJustLA $ Hs.RuleD noExtField $ HsRules { rds_ext = noAnn , rds_src = SourceText "{-# RULES" , rds_rules = [noLocA $ HsRule { rd_ext = noAnn , rd_name = (noLocA (quotedSourceText nm,nm')) , rd_act = act , rd_tyvs = ty_bndrs' , rd_tmvs = tm_bndrs' , rd_lhs = lhs' , rd_rhs = rhs' }] } } cvtPragmaD (AnnP target exp) = do { exp' <- cvtl exp ; target' <- case target of ModuleAnnotation -> return ModuleAnnProvenance TypeAnnotation n -> do n' <- tconName n return (TypeAnnProvenance (noLocA n')) ValueAnnotation n -> do n' <- vcName n return (ValueAnnProvenance (noLocA n')) ; returnJustLA $ Hs.AnnD noExtField $ HsAnnotation noAnn (SourceText "{-# ANN") target' exp' } cvtPragmaD (LineP line file) = do { setL (srcLocSpan (mkSrcLoc (fsLit file) line 1)) ; return Nothing } cvtPragmaD (CompleteP cls mty) = do { cls' <- noLoc <$> mapM cNameN cls ; mty' <- traverse tconNameN mty ; returnJustLA $ Hs.SigD noExtField $ CompleteMatchSig noAnn NoSourceText cls' mty' } dfltActivation :: TH.Inline -> Activation dfltActivation TH.NoInline = NeverActive dfltActivation _ = AlwaysActive cvtInline :: TH.Inline -> SourceText -> Hs.InlineSpec cvtInline TH.NoInline srcText = Hs.NoInline srcText cvtInline TH.Inline srcText = Hs.Inline srcText cvtInline TH.Inlinable srcText = Hs.Inlinable srcText cvtRuleMatch :: TH.RuleMatch -> RuleMatchInfo cvtRuleMatch TH.ConLike = Hs.ConLike cvtRuleMatch TH.FunLike = Hs.FunLike cvtPhases :: TH.Phases -> Activation -> Activation cvtPhases AllPhases dflt = dflt cvtPhases (FromPhase i) _ = ActiveAfter NoSourceText i cvtPhases (BeforePhase i) _ = ActiveBefore NoSourceText i cvtRuleBndr :: TH.RuleBndr -> CvtM (Hs.LRuleBndr GhcPs) cvtRuleBndr (RuleVar n) = do { n' <- vNameN n ; return $ noLocA $ Hs.RuleBndr noAnn n' } cvtRuleBndr (TypedRuleVar n ty) = do { n' <- vNameN n ; ty' <- cvtType ty ; return $ noLocA $ Hs.RuleBndrSig noAnn n' $ mkHsPatSigType noAnn ty' } --------------------------------------------------- -- Declarations --------------------------------------------------- cvtLocalDecs :: SDoc -> [TH.Dec] -> CvtM (HsLocalBinds GhcPs) cvtLocalDecs doc ds = case partitionWith is_ip_bind ds of ([], []) -> return (EmptyLocalBinds noExtField) ([], _) -> do ds' <- cvtDecs ds let (binds, prob_sigs) = partitionWith is_bind ds' let (sigs, bads) = partitionWith is_sig prob_sigs unless (null bads) (failWith (mkBadDecMsg doc bads)) return (HsValBinds noAnn (ValBinds NoAnnSortKey (listToBag binds) sigs)) (ip_binds, []) -> do binds <- mapM (uncurry cvtImplicitParamBind) ip_binds return (HsIPBinds noAnn (IPBinds noExtField binds)) ((_:_), (_:_)) -> failWith (text "Implicit parameters mixed with other bindings") cvtClause :: HsMatchContext GhcPs -> TH.Clause -> CvtM (Hs.LMatch GhcPs (LHsExpr GhcPs)) cvtClause ctxt (Clause ps body wheres) = do { ps' <- cvtPats ps ; let pps = map (parenthesizePat appPrec) ps' ; g' <- cvtGuard body ; ds' <- cvtLocalDecs (text "a where clause") wheres ; returnLA $ Hs.Match noAnn ctxt pps (GRHSs emptyComments g' ds') } cvtImplicitParamBind :: String -> TH.Exp -> CvtM (LIPBind GhcPs) cvtImplicitParamBind n e = do n' <- wrapL (ipName n) e' <- cvtl e returnLA (IPBind noAnn (Left (reLocA n')) e') ------------------------------------------------------------------- -- Expressions ------------------------------------------------------------------- cvtl :: TH.Exp -> CvtM (LHsExpr GhcPs) cvtl e = wrapLA (cvt e) where cvt (VarE s) = do { s' <- vName s; return $ HsVar noExtField (noLocA s') } cvt (ConE s) = do { s' <- cName s; return $ HsVar noExtField (noLocA s') } cvt (LitE l) | overloadedLit l = go cvtOverLit (HsOverLit noComments) (hsOverLitNeedsParens appPrec) | otherwise = go cvtLit (HsLit noComments) (hsLitNeedsParens appPrec) where go :: (Lit -> CvtM (l GhcPs)) -> (l GhcPs -> HsExpr GhcPs) -> (l GhcPs -> Bool) -> CvtM (HsExpr GhcPs) go cvt_lit mk_expr is_compound_lit = do l' <- cvt_lit l let e' = mk_expr l' return $ if is_compound_lit l' then gHsPar (noLocA e') else e' cvt (AppE x@(LamE _ _) y) = do { x' <- cvtl x; y' <- cvtl y ; return $ HsApp noComments (mkLHsPar x') (mkLHsPar y')} cvt (AppE x y) = do { x' <- cvtl x; y' <- cvtl y ; return $ HsApp noComments (mkLHsPar x') (mkLHsPar y')} cvt (AppTypeE e t) = do { e' <- cvtl e ; t' <- cvtType t ; let tp = parenthesizeHsType appPrec t' ; return $ HsAppType noSrcSpan e' $ mkHsWildCardBndrs tp } cvt (LamE [] e) = cvt e -- Degenerate case. We convert the body as its -- own expression to avoid pretty-printing -- oddities that can result from zero-argument -- lambda expressions. See #13856. cvt (LamE ps e) = do { ps' <- cvtPats ps; e' <- cvtl e ; let pats = map (parenthesizePat appPrec) ps' ; th_origin <- getOrigin ; return $ HsLam noExtField (mkMatchGroup th_origin (noLocA [mkSimpleMatch LambdaExpr pats e']))} cvt (LamCaseE ms) = do { ms' <- mapM (cvtMatch CaseAlt) ms ; th_origin <- getOrigin ; return $ HsLamCase noAnn (mkMatchGroup th_origin (noLocA ms')) } cvt (TupE es) = cvt_tup es Boxed cvt (UnboxedTupE es) = cvt_tup es Unboxed cvt (UnboxedSumE e alt arity) = do { e' <- cvtl e ; unboxedSumChecks alt arity ; return $ ExplicitSum noAnn alt arity e'} cvt (CondE x y z) = do { x' <- cvtl x; y' <- cvtl y; z' <- cvtl z; ; return $ mkHsIf x' y' z' noAnn } cvt (MultiIfE alts) | null alts = failWith (text "Multi-way if-expression with no alternatives") | otherwise = do { alts' <- mapM cvtpair alts ; return $ HsMultiIf noAnn alts' } cvt (LetE ds e) = do { ds' <- cvtLocalDecs (text "a let expression") ds ; e' <- cvtl e; return $ HsLet noAnn noHsTok ds' noHsTok e'} cvt (CaseE e ms) = do { e' <- cvtl e; ms' <- mapM (cvtMatch CaseAlt) ms ; th_origin <- getOrigin ; return $ HsCase noAnn e' (mkMatchGroup th_origin (noLocA ms')) } cvt (DoE m ss) = cvtHsDo (DoExpr (mk_mod <$> m)) ss cvt (MDoE m ss) = cvtHsDo (MDoExpr (mk_mod <$> m)) ss cvt (CompE ss) = cvtHsDo ListComp ss cvt (ArithSeqE dd) = do { dd' <- cvtDD dd ; return $ ArithSeq noAnn Nothing dd' } cvt (ListE xs) | Just s <- allCharLs xs = do { l' <- cvtLit (StringL s) ; return (HsLit noComments l') } -- Note [Converting strings] | otherwise = do { xs' <- mapM cvtl xs ; return $ ExplicitList noAnn xs' } -- Infix expressions cvt (InfixE (Just x) s (Just y)) = ensureValidOpExp s $ do { x' <- cvtl x ; s' <- cvtl s ; y' <- cvtl y ; let px = parenthesizeHsExpr opPrec x' py = parenthesizeHsExpr opPrec y' ; wrapParLA gHsPar $ OpApp noAnn px s' py } -- Parenthesise both arguments and result, -- to ensure this operator application does -- does not get re-associated -- See Note [Operator association] cvt (InfixE Nothing s (Just y)) = ensureValidOpExp s $ do { s' <- cvtl s; y' <- cvtl y ; wrapParLA gHsPar $ SectionR noComments s' y' } -- See Note [Sections in HsSyn] in GHC.Hs.Expr cvt (InfixE (Just x) s Nothing ) = ensureValidOpExp s $ do { x' <- cvtl x; s' <- cvtl s ; wrapParLA gHsPar $ SectionL noComments x' s' } cvt (InfixE Nothing s Nothing ) = ensureValidOpExp s $ do { s' <- cvtl s ; return $ gHsPar s' } -- Can I indicate this is an infix thing? -- Note [Dropping constructors] cvt (UInfixE x s y) = ensureValidOpExp s $ do { x' <- cvtl x ; let x'' = case unLoc x' of OpApp {} -> x' _ -> mkLHsPar x' ; cvtOpApp x'' s y } -- Note [Converting UInfix] cvt (ParensE e) = do { e' <- cvtl e; return $ gHsPar e' } cvt (SigE e t) = do { e' <- cvtl e; t' <- cvtSigType t ; let pe = parenthesizeHsExpr sigPrec e' ; return $ ExprWithTySig noAnn pe (mkHsWildCardBndrs t') } cvt (RecConE c flds) = do { c' <- cNameN c ; flds' <- mapM (cvtFld (mkFieldOcc . noLocA)) flds ; return $ mkRdrRecordCon c' (HsRecFields flds' Nothing) noAnn } cvt (RecUpdE e flds) = do { e' <- cvtl e ; flds' <- mapM (cvtFld (mkAmbiguousFieldOcc . noLocA)) flds ; return $ RecordUpd noAnn e' (Left flds') } cvt (StaticE e) = fmap (HsStatic noAnn) $ cvtl e cvt (UnboundVarE s) = do -- Use of 'vcName' here instead of 'vName' is -- important, because UnboundVarE may contain -- constructor names - see #14627. { s' <- vcName s ; return $ HsVar noExtField (noLocA s') } cvt (LabelE s) = return $ HsOverLabel noComments (fsLit s) cvt (ImplicitParamVarE n) = do { n' <- ipName n; return $ HsIPVar noComments n' } cvt (GetFieldE exp f) = do { e' <- cvtl exp ; return $ HsGetField noComments e' (L noSrcSpanA (DotFieldOcc noAnn (L noSrcSpanA (fsLit f)))) } cvt (ProjectionE xs) = return $ HsProjection noAnn $ fmap (L noSrcSpanA . DotFieldOcc noAnn . L noSrcSpanA . fsLit) xs {- | #16895 Ensure an infix expression's operator is a variable/constructor. Consider this example: $(uInfixE [|1|] [|id id|] [|2|]) This infix expression is obviously ill-formed so we use this helper function to reject such programs outright. The constructors `ensureValidOpExp` permits should be in sync with `pprInfixExp` in Language.Haskell.TH.Ppr from the template-haskell library. -} ensureValidOpExp :: TH.Exp -> CvtM a -> CvtM a ensureValidOpExp (VarE _n) m = m ensureValidOpExp (ConE _n) m = m ensureValidOpExp (UnboundVarE _n) m = m ensureValidOpExp _e _m = failWith (text "Non-variable expression is not allowed in an infix expression") {- Note [Dropping constructors] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ When we drop constructors from the input, we must insert parentheses around the argument. For example: UInfixE x * (AppE (InfixE (Just y) + Nothing) z) If we convert the InfixE expression to an operator section but don't insert parentheses, the above expression would be reassociated to OpApp (OpApp x * y) + z which we don't want. -} cvtFld :: (RdrName -> t) -> (TH.Name, TH.Exp) -> CvtM (LHsFieldBind GhcPs (LocatedAn NoEpAnns t) (LHsExpr GhcPs)) cvtFld f (v,e) = do { v' <- vNameL v; e' <- cvtl e ; return (noLocA $ HsFieldBind { hfbAnn = noAnn , hfbLHS = la2la $ fmap f v' , hfbRHS = e' , hfbPun = False}) } cvtDD :: Range -> CvtM (ArithSeqInfo GhcPs) cvtDD (FromR x) = do { x' <- cvtl x; return $ From x' } cvtDD (FromThenR x y) = do { x' <- cvtl x; y' <- cvtl y; return $ FromThen x' y' } cvtDD (FromToR x y) = do { x' <- cvtl x; y' <- cvtl y; return $ FromTo x' y' } cvtDD (FromThenToR x y z) = do { x' <- cvtl x; y' <- cvtl y; z' <- cvtl z; return $ FromThenTo x' y' z' } cvt_tup :: [Maybe Exp] -> Boxity -> CvtM (HsExpr GhcPs) cvt_tup es boxity = do { let cvtl_maybe Nothing = return (missingTupArg noAnn) cvtl_maybe (Just e) = fmap (Present noAnn) (cvtl e) ; es' <- mapM cvtl_maybe es ; return $ ExplicitTuple noAnn es' boxity } {- Note [Operator association] ~~~~~~~~~~~~~~~~~~~~~~~~~~~ We must be quite careful about adding parens: * Infix (UInfix ...) op arg Needs parens round the first arg * Infix (Infix ...) op arg Needs parens round the first arg * UInfix (UInfix ...) op arg No parens for first arg * UInfix (Infix ...) op arg Needs parens round first arg Note [Converting UInfix] ~~~~~~~~~~~~~~~~~~~~~~~~ When converting @UInfixE@, @UInfixP@, @UInfixT@, and @PromotedUInfixT@ values, we want to readjust the trees to reflect the fixities of the underlying operators: UInfixE x * (UInfixE y + z) ---> (x * y) + z This is done by the renamer (see @mkOppAppRn@, @mkConOppPatRn@, and @mkHsOpTyRn@ in GHC.Rename.HsType), which expects that the input will be completely right-biased for types and left-biased for everything else. So we left-bias the trees of @UInfixP@ and @UInfixE@ and right-bias the trees of @UInfixT@ and @PromotedUnfixT@. Sample input: UInfixE (UInfixE x op1 y) op2 (UInfixE z op3 w) Sample output: OpApp (OpApp (OpApp x op1 y) op2 z) op3 w The functions @cvtOpApp@, @cvtOpAppP@, and @cvtOpAppT@ are responsible for this biasing. -} {- | @cvtOpApp x op y@ converts @op@ and @y@ and produces the operator application @x `op` y@. The produced tree of infix expressions will be left-biased, provided @x@ is. We can see that @cvtOpApp@ is correct as follows. The inductive hypothesis is that @cvtOpApp x op y@ is left-biased, provided @x@ is. It is clear that this holds for both branches (of @cvtOpApp@), provided we assume it holds for the recursive calls to @cvtOpApp@. When we call @cvtOpApp@ from @cvtl@, the first argument will always be left-biased since we have already run @cvtl@ on it. -} cvtOpApp :: LHsExpr GhcPs -> TH.Exp -> TH.Exp -> CvtM (HsExpr GhcPs) cvtOpApp x op1 (UInfixE y op2 z) = do { l <- wrapLA $ cvtOpApp x op1 y ; cvtOpApp l op2 z } cvtOpApp x op y = do { op' <- cvtl op ; y' <- cvtl y ; return (OpApp noAnn x op' y') } ------------------------------------- -- Do notation and statements ------------------------------------- cvtHsDo :: HsDoFlavour -> [TH.Stmt] -> CvtM (HsExpr GhcPs) cvtHsDo do_or_lc stmts | null stmts = failWith (text "Empty stmt list in do-block") | otherwise = do { stmts' <- cvtStmts stmts ; let Just (stmts'', last') = snocView stmts' ; last'' <- case last' of (L loc (BodyStmt _ body _ _)) -> return (L loc (mkLastStmt body)) _ -> failWith (bad_last last') ; return $ HsDo noAnn do_or_lc (noLocA (stmts'' ++ [last''])) } where bad_last stmt = vcat [ text "Illegal last statement of" <+> pprAHsDoFlavour do_or_lc <> colon , nest 2 $ Outputable.ppr stmt , text "(It should be an expression.)" ] cvtStmts :: [TH.Stmt] -> CvtM [Hs.LStmt GhcPs (LHsExpr GhcPs)] cvtStmts = mapM cvtStmt cvtStmt :: TH.Stmt -> CvtM (Hs.LStmt GhcPs (LHsExpr GhcPs)) cvtStmt (NoBindS e) = do { e' <- cvtl e; returnLA $ mkBodyStmt e' } cvtStmt (TH.BindS p e) = do { p' <- cvtPat p; e' <- cvtl e; returnLA $ mkPsBindStmt noAnn p' e' } cvtStmt (TH.LetS ds) = do { ds' <- cvtLocalDecs (text "a let binding") ds ; returnLA $ LetStmt noAnn ds' } cvtStmt (TH.ParS dss) = do { dss' <- mapM cvt_one dss ; returnLA $ ParStmt noExtField dss' noExpr noSyntaxExpr } where cvt_one ds = do { ds' <- cvtStmts ds ; return (ParStmtBlock noExtField ds' undefined noSyntaxExpr) } cvtStmt (TH.RecS ss) = do { ss' <- mapM cvtStmt ss; returnLA (mkRecStmt noAnn (noLocA ss')) } cvtMatch :: HsMatchContext GhcPs -> TH.Match -> CvtM (Hs.LMatch GhcPs (LHsExpr GhcPs)) cvtMatch ctxt (TH.Match p body decs) = do { p' <- cvtPat p ; let lp = case p' of (L loc SigPat{}) -> L loc (gParPat p') -- #14875 _ -> p' ; g' <- cvtGuard body ; decs' <- cvtLocalDecs (text "a where clause") decs ; returnLA $ Hs.Match noAnn ctxt [lp] (GRHSs emptyComments g' decs') } cvtGuard :: TH.Body -> CvtM [LGRHS GhcPs (LHsExpr GhcPs)] cvtGuard (GuardedB pairs) = mapM cvtpair pairs cvtGuard (NormalB e) = do { e' <- cvtl e ; g' <- returnLA $ GRHS noAnn [] e'; return [g'] } cvtpair :: (TH.Guard, TH.Exp) -> CvtM (LGRHS GhcPs (LHsExpr GhcPs)) cvtpair (NormalG ge,rhs) = do { ge' <- cvtl ge; rhs' <- cvtl rhs ; g' <- returnLA $ mkBodyStmt ge' ; returnLA $ GRHS noAnn [g'] rhs' } cvtpair (PatG gs,rhs) = do { gs' <- cvtStmts gs; rhs' <- cvtl rhs ; returnLA $ GRHS noAnn gs' rhs' } cvtOverLit :: Lit -> CvtM (HsOverLit GhcPs) cvtOverLit (IntegerL i) = do { force i; return $ mkHsIntegral (mkIntegralLit i) } cvtOverLit (RationalL r) = do { force r; return $ mkHsFractional (mkTHFractionalLit r) } cvtOverLit (StringL s) = do { let { s' = mkFastString s } ; force s' ; return $ mkHsIsString (quotedSourceText s) s' } cvtOverLit _ = panic "Convert.cvtOverLit: Unexpected overloaded literal" -- An Integer is like an (overloaded) '3' in a Haskell source program -- Similarly 3.5 for fractionals {- Note [Converting strings] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~ If we get (ListE [CharL 'x', CharL 'y']) we'd like to convert to a string literal for "xy". Of course, we might hope to get (LitE (StringL "xy")), but not always, and allCharLs fails quickly if it isn't a literal string -} allCharLs :: [TH.Exp] -> Maybe String -- Note [Converting strings] -- NB: only fire up this setup for a non-empty list, else -- there's a danger of returning "" for [] :: [Int]! allCharLs xs = case xs of LitE (CharL c) : ys -> go [c] ys _ -> Nothing where go cs [] = Just (reverse cs) go cs (LitE (CharL c) : ys) = go (c:cs) ys go _ _ = Nothing cvtLit :: Lit -> CvtM (HsLit GhcPs) cvtLit (IntPrimL i) = do { force i; return $ HsIntPrim NoSourceText i } cvtLit (WordPrimL w) = do { force w; return $ HsWordPrim NoSourceText w } cvtLit (FloatPrimL f) = do { force f; return $ HsFloatPrim noExtField (mkTHFractionalLit f) } cvtLit (DoublePrimL f) = do { force f; return $ HsDoublePrim noExtField (mkTHFractionalLit f) } cvtLit (CharL c) = do { force c; return $ HsChar NoSourceText c } cvtLit (CharPrimL c) = do { force c; return $ HsCharPrim NoSourceText c } cvtLit (StringL s) = do { let { s' = mkFastString s } ; force s' ; return $ HsString (quotedSourceText s) s' } cvtLit (StringPrimL s) = do { let { !s' = BS.pack s } ; return $ HsStringPrim NoSourceText s' } cvtLit (BytesPrimL (Bytes fptr off sz)) = do let bs = unsafePerformIO $ withForeignPtr fptr $ \ptr -> BS.packCStringLen (ptr `plusPtr` fromIntegral off, fromIntegral sz) force bs return $ HsStringPrim NoSourceText bs cvtLit _ = panic "Convert.cvtLit: Unexpected literal" -- cvtLit should not be called on IntegerL, RationalL -- That precondition is established right here in -- "GHC.ThToHs", hence panic quotedSourceText :: String -> SourceText quotedSourceText s = SourceText $ "\"" ++ s ++ "\"" cvtPats :: [TH.Pat] -> CvtM [Hs.LPat GhcPs] cvtPats pats = mapM cvtPat pats cvtPat :: TH.Pat -> CvtM (Hs.LPat GhcPs) cvtPat pat = wrapLA (cvtp pat) cvtp :: TH.Pat -> CvtM (Hs.Pat GhcPs) cvtp (TH.LitP l) | overloadedLit l = do { l' <- cvtOverLit l ; return (mkNPat (noLocA l') Nothing noAnn) } -- Not right for negative patterns; -- need to think about that! | otherwise = do { l' <- cvtLit l; return $ Hs.LitPat noExtField l' } cvtp (TH.VarP s) = do { s' <- vName s ; return $ Hs.VarPat noExtField (noLocA s') } cvtp (TupP ps) = do { ps' <- cvtPats ps ; return $ TuplePat noAnn ps' Boxed } cvtp (UnboxedTupP ps) = do { ps' <- cvtPats ps ; return $ TuplePat noAnn ps' Unboxed } cvtp (UnboxedSumP p alt arity) = do { p' <- cvtPat p ; unboxedSumChecks alt arity ; return $ SumPat noAnn p' alt arity } cvtp (ConP s ts ps) = do { s' <- cNameN s ; ps' <- cvtPats ps ; ts' <- mapM cvtType ts ; let pps = map (parenthesizePat appPrec) ps' ; return $ ConPat { pat_con_ext = noAnn , pat_con = s' , pat_args = PrefixCon (map (mkHsPatSigType noAnn) ts') pps } } cvtp (InfixP p1 s p2) = do { s' <- cNameN s; p1' <- cvtPat p1; p2' <- cvtPat p2 ; wrapParLA gParPat $ ConPat { pat_con_ext = noAnn , pat_con = s' , pat_args = InfixCon (parenthesizePat opPrec p1') (parenthesizePat opPrec p2') } } -- See Note [Operator association] cvtp (UInfixP p1 s p2) = do { p1' <- cvtPat p1; cvtOpAppP p1' s p2 } -- Note [Converting UInfix] cvtp (ParensP p) = do { p' <- cvtPat p; ; case unLoc p' of -- may be wrapped ConPatIn ParPat {} -> return $ unLoc p' _ -> return $ gParPat p' } cvtp (TildeP p) = do { p' <- cvtPat p; return $ LazyPat noAnn p' } cvtp (BangP p) = do { p' <- cvtPat p; return $ BangPat noAnn p' } cvtp (TH.AsP s p) = do { s' <- vNameN s; p' <- cvtPat p ; return $ AsPat noAnn s' p' } cvtp TH.WildP = return $ WildPat noExtField cvtp (RecP c fs) = do { c' <- cNameN c; fs' <- mapM cvtPatFld fs ; return $ ConPat { pat_con_ext = noAnn , pat_con = c' , pat_args = Hs.RecCon $ HsRecFields fs' Nothing } } cvtp (ListP ps) = do { ps' <- cvtPats ps ; return $ ListPat noAnn ps'} cvtp (SigP p t) = do { p' <- cvtPat p; t' <- cvtType t ; return $ SigPat noAnn p' (mkHsPatSigType noAnn t') } cvtp (ViewP e p) = do { e' <- cvtl e; p' <- cvtPat p ; return $ ViewPat noAnn e' p'} cvtPatFld :: (TH.Name, TH.Pat) -> CvtM (LHsRecField GhcPs (LPat GhcPs)) cvtPatFld (s,p) = do { L ls s' <- vNameN s ; p' <- cvtPat p ; return (noLocA $ HsFieldBind { hfbAnn = noAnn , hfbLHS = L (l2l ls) $ mkFieldOcc (L (l2l ls) s') , hfbRHS = p' , hfbPun = False}) } {- | @cvtOpAppP x op y@ converts @op@ and @y@ and produces the operator application @x `op` y@. The produced tree of infix patterns will be left-biased, provided @x@ is. See the @cvtOpApp@ documentation for how this function works. -} cvtOpAppP :: Hs.LPat GhcPs -> TH.Name -> TH.Pat -> CvtM (Hs.Pat GhcPs) cvtOpAppP x op1 (UInfixP y op2 z) = do { l <- wrapLA $ cvtOpAppP x op1 y ; cvtOpAppP l op2 z } cvtOpAppP x op y = do { op' <- cNameN op ; y' <- cvtPat y ; return $ ConPat { pat_con_ext = noAnn , pat_con = op' , pat_args = InfixCon x y' } } ----------------------------------------------------------- -- Types and type variables class CvtFlag flag flag' | flag -> flag' where cvtFlag :: flag -> flag' instance CvtFlag () () where cvtFlag () = () instance CvtFlag TH.Specificity Hs.Specificity where cvtFlag TH.SpecifiedSpec = Hs.SpecifiedSpec cvtFlag TH.InferredSpec = Hs.InferredSpec cvtTvs :: CvtFlag flag flag' => [TH.TyVarBndr flag] -> CvtM [LHsTyVarBndr flag' GhcPs] cvtTvs tvs = mapM cvt_tv tvs cvt_tv :: CvtFlag flag flag' => (TH.TyVarBndr flag) -> CvtM (LHsTyVarBndr flag' GhcPs) cvt_tv (TH.PlainTV nm fl) = do { nm' <- tNameN nm ; let fl' = cvtFlag fl ; returnLA $ UserTyVar noAnn fl' nm' } cvt_tv (TH.KindedTV nm fl ki) = do { nm' <- tNameN nm ; let fl' = cvtFlag fl ; ki' <- cvtKind ki ; returnLA $ KindedTyVar noAnn fl' nm' ki' } cvtRole :: TH.Role -> Maybe Coercion.Role cvtRole TH.NominalR = Just Coercion.Nominal cvtRole TH.RepresentationalR = Just Coercion.Representational cvtRole TH.PhantomR = Just Coercion.Phantom cvtRole TH.InferR = Nothing cvtContext :: PprPrec -> TH.Cxt -> CvtM (LHsContext GhcPs) cvtContext p tys = do { preds' <- mapM cvtPred tys ; parenthesizeHsContext p <$> returnLA preds' } cvtPred :: TH.Pred -> CvtM (LHsType GhcPs) cvtPred = cvtType cvtDerivClauseTys :: TH.Cxt -> CvtM (LDerivClauseTys GhcPs) cvtDerivClauseTys tys = do { tys' <- mapM cvtSigType tys -- Since TH.Cxt doesn't indicate the presence or absence of -- parentheses in a deriving clause, we have to choose between -- DctSingle and DctMulti somewhat arbitrarily. We opt to use DctMulti -- unless the TH.Cxt is a singleton list whose type is a bare type -- constructor with no arguments. ; case tys' of [ty'@(L l (HsSig { sig_bndrs = HsOuterImplicit{} , sig_body = L _ (HsTyVar _ NotPromoted _) }))] -> return $ L (l2l l) $ DctSingle noExtField ty' _ -> returnLA $ DctMulti noExtField tys' } cvtDerivClause :: TH.DerivClause -> CvtM (LHsDerivingClause GhcPs) cvtDerivClause (TH.DerivClause ds tys) = do { tys' <- cvtDerivClauseTys tys ; ds' <- traverse cvtDerivStrategy ds ; returnLA $ HsDerivingClause noAnn ds' tys' } cvtDerivStrategy :: TH.DerivStrategy -> CvtM (Hs.LDerivStrategy GhcPs) cvtDerivStrategy TH.StockStrategy = returnLA (Hs.StockStrategy noAnn) cvtDerivStrategy TH.AnyclassStrategy = returnLA (Hs.AnyclassStrategy noAnn) cvtDerivStrategy TH.NewtypeStrategy = returnLA (Hs.NewtypeStrategy noAnn) cvtDerivStrategy (TH.ViaStrategy ty) = do ty' <- cvtSigType ty returnLA $ Hs.ViaStrategy (XViaStrategyPs noAnn ty') cvtType :: TH.Type -> CvtM (LHsType GhcPs) cvtType = cvtTypeKind "type" cvtSigType :: TH.Type -> CvtM (LHsSigType GhcPs) cvtSigType = cvtSigTypeKind "type" -- | Convert a Template Haskell 'Type' to an 'LHsSigType'. To avoid duplicating -- the logic in 'cvtTypeKind' here, we simply reuse 'cvtTypeKind' and perform -- surgery on the 'LHsType' it returns to turn it into an 'LHsSigType'. cvtSigTypeKind :: String -> TH.Type -> CvtM (LHsSigType GhcPs) cvtSigTypeKind ty_str ty = do ty' <- cvtTypeKind ty_str ty pure $ hsTypeToHsSigType ty' cvtTypeKind :: String -> TH.Type -> CvtM (LHsType GhcPs) cvtTypeKind ty_str ty = do { (head_ty, tys') <- split_ty_app ty ; let m_normals = mapM extract_normal tys' where extract_normal (HsValArg ty) = Just ty extract_normal _ = Nothing ; case head_ty of TupleT n | Just normals <- m_normals , normals `lengthIs` n -- Saturated -> returnLA (HsTupleTy noAnn HsBoxedOrConstraintTuple normals) | otherwise -> mk_apps (HsTyVar noAnn NotPromoted (noLocA (getRdrName (tupleTyCon Boxed n)))) tys' UnboxedTupleT n | Just normals <- m_normals , normals `lengthIs` n -- Saturated -> returnLA (HsTupleTy noAnn HsUnboxedTuple normals) | otherwise -> mk_apps (HsTyVar noAnn NotPromoted (noLocA (getRdrName (tupleTyCon Unboxed n)))) tys' UnboxedSumT n | n < 2 -> failWith $ vcat [ text "Illegal sum arity:" <+> text (show n) , nest 2 $ text "Sums must have an arity of at least 2" ] | Just normals <- m_normals , normals `lengthIs` n -- Saturated -> returnLA (HsSumTy noAnn normals) | otherwise -> mk_apps (HsTyVar noAnn NotPromoted (noLocA (getRdrName (sumTyCon n)))) tys' ArrowT | Just normals <- m_normals , [x',y'] <- normals -> do x'' <- case unLoc x' of HsFunTy{} -> returnLA (HsParTy noAnn x') HsForAllTy{} -> returnLA (HsParTy noAnn x') -- #14646 HsQualTy{} -> returnLA (HsParTy noAnn x') -- #15324 _ -> return $ parenthesizeHsType sigPrec x' let y'' = parenthesizeHsType sigPrec y' returnLA (HsFunTy noAnn (HsUnrestrictedArrow noHsUniTok) x'' y'') | otherwise -> mk_apps (HsTyVar noAnn NotPromoted (noLocA (getRdrName unrestrictedFunTyCon))) tys' MulArrowT | Just normals <- m_normals , [w',x',y'] <- normals -> do x'' <- case unLoc x' of HsFunTy{} -> returnLA (HsParTy noAnn x') HsForAllTy{} -> returnLA (HsParTy noAnn x') -- #14646 HsQualTy{} -> returnLA (HsParTy noAnn x') -- #15324 _ -> return $ parenthesizeHsType sigPrec x' let y'' = parenthesizeHsType sigPrec y' w'' = hsTypeToArrow w' returnLA (HsFunTy noAnn w'' x'' y'') | otherwise -> mk_apps (HsTyVar noAnn NotPromoted (noLocA (getRdrName funTyCon))) tys' ListT | Just normals <- m_normals , [x'] <- normals -> returnLA (HsListTy noAnn x') | otherwise -> mk_apps (HsTyVar noAnn NotPromoted (noLocA (getRdrName listTyCon))) tys' VarT nm -> do { nm' <- tNameN nm ; mk_apps (HsTyVar noAnn NotPromoted nm') tys' } ConT nm -> do { nm' <- tconName nm ; let prom = name_promotedness nm' ; mk_apps (HsTyVar noAnn prom (noLocA nm')) tys'} ForallT tvs cxt ty | null tys' -> do { tvs' <- cvtTvs tvs ; cxt' <- cvtContext funPrec cxt ; ty' <- cvtType ty ; loc <- getL ; let loc' = noAnnSrcSpan loc ; let tele = mkHsForAllInvisTele noAnn tvs' hs_ty = mkHsForAllTy loc' tele rho_ty rho_ty = mkHsQualTy cxt loc' cxt' ty' ; return hs_ty } ForallVisT tvs ty | null tys' -> do { tvs' <- cvtTvs tvs ; ty' <- cvtType ty ; loc <- getL ; let loc' = noAnnSrcSpan loc ; let tele = mkHsForAllVisTele noAnn tvs' ; pure $ mkHsForAllTy loc' tele ty' } SigT ty ki -> do { ty' <- cvtType ty ; ki' <- cvtKind ki ; mk_apps (HsKindSig noAnn ty' ki') tys' } LitT lit -> mk_apps (HsTyLit noExtField (cvtTyLit lit)) tys' WildCardT -> mk_apps mkAnonWildCardTy tys' InfixT t1 s t2 -> do { s' <- tconName s ; t1' <- cvtType t1 ; t2' <- cvtType t2 ; let prom = name_promotedness s' ; mk_apps (HsTyVar noAnn prom (noLocA s')) ([HsValArg t1', HsValArg t2'] ++ tys') } UInfixT t1 s t2 -> do { s' <- tconNameN s ; t2' <- cvtType t2 ; t <- cvtOpAppT t1 s' t2' ; mk_apps (unLoc t) tys' } -- Note [Converting UInfix] PromotedInfixT t1 s t2 -> do { s' <- cName s ; t1' <- cvtType t1 ; t2' <- cvtType t2 ; mk_apps (HsTyVar noAnn IsPromoted (noLocA s')) ([HsValArg t1', HsValArg t2'] ++ tys') } PromotedUInfixT t1 s t2 -> do { s' <- cNameN s ; t2' <- cvtType t2 ; t <- cvtOpAppT t1 s' t2' ; mk_apps (unLoc t) tys' } -- Note [Converting UInfix] ParensT t -> do { t' <- cvtType t ; mk_apps (HsParTy noAnn t') tys' } PromotedT nm -> do { nm' <- cName nm ; mk_apps (HsTyVar noAnn IsPromoted (noLocA nm')) tys' } -- Promoted data constructor; hence cName PromotedTupleT n | Just normals <- m_normals , normals `lengthIs` n -- Saturated -> returnLA (HsExplicitTupleTy noAnn normals) | otherwise -> mk_apps (HsTyVar noAnn IsPromoted (noLocA (getRdrName (tupleDataCon Boxed n)))) tys' PromotedNilT -> mk_apps (HsExplicitListTy noAnn IsPromoted []) tys' PromotedConsT -- See Note [Representing concrete syntax in types] -- in Language.Haskell.TH.Syntax | Just normals <- m_normals , [ty1, L _ (HsExplicitListTy _ ip tys2)] <- normals -> returnLA (HsExplicitListTy noAnn ip (ty1:tys2)) | otherwise -> mk_apps (HsTyVar noAnn IsPromoted (noLocA (getRdrName consDataCon))) tys' StarT -> mk_apps (HsTyVar noAnn NotPromoted (noLocA (getRdrName liftedTypeKindTyCon))) tys' ConstraintT -> mk_apps (HsTyVar noAnn NotPromoted (noLocA (getRdrName constraintKindTyCon))) tys' EqualityT | Just normals <- m_normals , [x',y'] <- normals -> let px = parenthesizeHsType opPrec x' py = parenthesizeHsType opPrec y' in returnLA (HsOpTy noExtField px (noLocA eqTyCon_RDR) py) -- The long-term goal is to remove the above case entirely and -- subsume it under the case for InfixT. See #15815, comment:6, -- for more details. | otherwise -> mk_apps (HsTyVar noAnn NotPromoted (noLocA eqTyCon_RDR)) tys' ImplicitParamT n t -> do { n' <- wrapL $ ipName n ; t' <- cvtType t ; returnLA (HsIParamTy noAnn (reLocA n') t') } _ -> failWith (text "Malformed " <> text ty_str <+> text (show ty)) } hsTypeToArrow :: LHsType GhcPs -> HsArrow GhcPs hsTypeToArrow w = case unLoc w of HsTyVar _ _ (L _ (isExact_maybe -> Just n)) | n == oneDataConName -> HsLinearArrow (HsPct1 noHsTok noHsUniTok) | n == manyDataConName -> HsUnrestrictedArrow noHsUniTok _ -> HsExplicitMult noHsTok w noHsUniTok -- ConT/InfixT can contain both data constructor (i.e., promoted) names and -- other (i.e, unpromoted) names, as opposed to PromotedT, which can only -- contain data constructor names. See #15572/#17394. We use this function to -- determine whether to mark a name as promoted/unpromoted when dealing with -- ConT/InfixT. name_promotedness :: RdrName -> Hs.PromotionFlag name_promotedness nm | isRdrDataCon nm = IsPromoted | otherwise = NotPromoted -- | Constructs an application of a type to arguments passed in a list. mk_apps :: HsType GhcPs -> [LHsTypeArg GhcPs] -> CvtM (LHsType GhcPs) mk_apps head_ty type_args = do head_ty' <- returnLA head_ty -- We must parenthesize the function type in case of an explicit -- signature. For instance, in `(Maybe :: Type -> Type) Int`, there -- _must_ be parentheses around `Maybe :: Type -> Type`. let phead_ty :: LHsType GhcPs phead_ty = parenthesizeHsType sigPrec head_ty' go :: [LHsTypeArg GhcPs] -> CvtM (LHsType GhcPs) go [] = pure head_ty' go (arg:args) = case arg of HsValArg ty -> do p_ty <- add_parens ty mk_apps (HsAppTy noExtField phead_ty p_ty) args HsTypeArg l ki -> do p_ki <- add_parens ki mk_apps (HsAppKindTy l phead_ty p_ki) args HsArgPar _ -> mk_apps (HsParTy noAnn phead_ty) args go type_args where -- See Note [Adding parens for splices] add_parens lt@(L _ t) | hsTypeNeedsParens appPrec t = returnLA (HsParTy noAnn lt) | otherwise = return lt wrap_tyarg :: LHsTypeArg GhcPs -> LHsTypeArg GhcPs wrap_tyarg (HsValArg ty) = HsValArg $ parenthesizeHsType appPrec ty wrap_tyarg (HsTypeArg l ki) = HsTypeArg l $ parenthesizeHsType appPrec ki wrap_tyarg ta@(HsArgPar {}) = ta -- Already parenthesized -- --------------------------------------------------------------------- -- Note [Adding parens for splices] {- The hsSyn representation of parsed source explicitly contains all the original parens, as written in the source. When a Template Haskell (TH) splice is evaluated, the original splice is first renamed and type checked and then finally converted to core in GHC.HsToCore.Quote. This core is then run in the TH engine, and the result comes back as a TH AST. In the process, all parens are stripped out, as they are not needed. This Convert module then converts the TH AST back to hsSyn AST. In order to pretty-print this hsSyn AST, parens need to be adde back at certain points so that the code is readable with its original meaning. So scattered through "GHC.ThToHs" are various points where parens are added. See (among other closed issues) https://gitlab.haskell.org/ghc/ghc/issues/14289 -} -- --------------------------------------------------------------------- split_ty_app :: TH.Type -> CvtM (TH.Type, [LHsTypeArg GhcPs]) split_ty_app ty = go ty [] where go (AppT f a) as' = do { a' <- cvtType a; go f (HsValArg a':as') } go (AppKindT ty ki) as' = do { ki' <- cvtKind ki ; go ty (HsTypeArg noSrcSpan ki':as') } go (ParensT t) as' = do { loc <- getL; go t (HsArgPar loc: as') } go f as = return (f,as) cvtTyLit :: TH.TyLit -> HsTyLit cvtTyLit (TH.NumTyLit i) = HsNumTy NoSourceText i cvtTyLit (TH.StrTyLit s) = HsStrTy NoSourceText (fsLit s) cvtTyLit (TH.CharTyLit c) = HsCharTy NoSourceText c {- | @cvtOpAppT x op y@ converts @op@ and @y@ and produces the operator application @x `op` y@. The produced tree of infix types will be right-biased, provided @y@ is. See the @cvtOpApp@ documentation for how this function works. -} cvtOpAppT :: TH.Type -> LocatedN RdrName -> LHsType GhcPs -> CvtM (LHsType GhcPs) cvtOpAppT (UInfixT x op2 y) op1 z = do { op2' <- tconNameN op2 ; l <- cvtOpAppT y op1 z ; cvtOpAppT x op2' l } cvtOpAppT (PromotedUInfixT x op2 y) op1 z = do { op2' <- cNameN op2 ; l <- cvtOpAppT y op1 z ; cvtOpAppT x op2' l } cvtOpAppT x op y = do { x' <- cvtType x ; returnLA (mkHsOpTy x' op y) } cvtKind :: TH.Kind -> CvtM (LHsKind GhcPs) cvtKind = cvtTypeKind "kind" cvtSigKind :: TH.Kind -> CvtM (LHsSigType GhcPs) cvtSigKind = cvtSigTypeKind "kind" -- | Convert Maybe Kind to a type family result signature. Used with data -- families where naming of the result is not possible (thus only kind or no -- signature is possible). cvtMaybeKindToFamilyResultSig :: Maybe TH.Kind -> CvtM (LFamilyResultSig GhcPs) cvtMaybeKindToFamilyResultSig Nothing = returnLA (Hs.NoSig noExtField) cvtMaybeKindToFamilyResultSig (Just ki) = do { ki' <- cvtKind ki ; returnLA (Hs.KindSig noExtField ki') } -- | Convert type family result signature. Used with both open and closed type -- families. cvtFamilyResultSig :: TH.FamilyResultSig -> CvtM (Hs.LFamilyResultSig GhcPs) cvtFamilyResultSig TH.NoSig = returnLA (Hs.NoSig noExtField) cvtFamilyResultSig (TH.KindSig ki) = do { ki' <- cvtKind ki ; returnLA (Hs.KindSig noExtField ki') } cvtFamilyResultSig (TH.TyVarSig bndr) = do { tv <- cvt_tv bndr ; returnLA (Hs.TyVarSig noExtField tv) } -- | Convert injectivity annotation of a type family. cvtInjectivityAnnotation :: TH.InjectivityAnn -> CvtM (Hs.LInjectivityAnn GhcPs) cvtInjectivityAnnotation (TH.InjectivityAnn annLHS annRHS) = do { annLHS' <- tNameN annLHS ; annRHS' <- mapM tNameN annRHS ; returnLA (Hs.InjectivityAnn noAnn annLHS' annRHS') } cvtPatSynSigTy :: TH.Type -> CvtM (LHsSigType GhcPs) -- pattern synonym types are of peculiar shapes, which is why we treat -- them separately from regular types; -- see Note [Pattern synonym type signatures and Template Haskell] cvtPatSynSigTy (ForallT univs reqs (ForallT exis provs ty)) | null exis, null provs = cvtSigType (ForallT univs reqs ty) | null univs, null reqs = do { l' <- getL ; let l = noAnnSrcSpan l' ; ty' <- cvtType (ForallT exis provs ty) ; return $ L l $ mkHsImplicitSigType $ L l (HsQualTy { hst_ctxt = noLocA [] , hst_xqual = noExtField , hst_body = ty' }) } | null reqs = do { l' <- getL ; let l'' = noAnnSrcSpan l' ; univs' <- cvtTvs univs ; ty' <- cvtType (ForallT exis provs ty) ; let forTy = mkHsExplicitSigType noAnn univs' $ L l'' cxtTy cxtTy = HsQualTy { hst_ctxt = noLocA [] , hst_xqual = noExtField , hst_body = ty' } ; return $ L (noAnnSrcSpan l') forTy } | otherwise = cvtSigType (ForallT univs reqs (ForallT exis provs ty)) cvtPatSynSigTy ty = cvtSigType ty ----------------------------------------------------------- cvtFixity :: TH.Fixity -> Hs.Fixity cvtFixity (TH.Fixity prec dir) = Hs.Fixity NoSourceText prec (cvt_dir dir) where cvt_dir TH.InfixL = Hs.InfixL cvt_dir TH.InfixR = Hs.InfixR cvt_dir TH.InfixN = Hs.InfixN ----------------------------------------------------------- ----------------------------------------------------------- -- some useful things overloadedLit :: Lit -> Bool -- True for literals that Haskell treats as overloaded overloadedLit (IntegerL _) = True overloadedLit (RationalL _) = True overloadedLit _ = False -- Checks that are performed when converting unboxed sum expressions and -- patterns alike. unboxedSumChecks :: TH.SumAlt -> TH.SumArity -> CvtM () unboxedSumChecks alt arity | alt > arity = failWith $ text "Sum alternative" <+> text (show alt) <+> text "exceeds its arity," <+> text (show arity) | alt <= 0 = failWith $ vcat [ text "Illegal sum alternative:" <+> text (show alt) , nest 2 $ text "Sum alternatives must start from 1" ] | arity < 2 = failWith $ vcat [ text "Illegal sum arity:" <+> text (show arity) , nest 2 $ text "Sums must have an arity of at least 2" ] | otherwise = return () -- | If passed an empty list of 'LHsTyVarBndr's, this simply returns the -- third argument (an 'LHsType'). Otherwise, return an 'HsForAllTy' -- using the provided 'LHsQTyVars' and 'LHsType'. mkHsForAllTy :: SrcSpanAnnA -- ^ The location of the returned 'LHsType' if it needs an -- explicit forall -> HsForAllTelescope GhcPs -- ^ The converted type variable binders -> LHsType GhcPs -- ^ The converted rho type -> LHsType GhcPs -- ^ The complete type, quantified with a forall if necessary mkHsForAllTy loc tele rho_ty | no_tvs = rho_ty | otherwise = L loc $ HsForAllTy { hst_tele = tele , hst_xforall = noExtField , hst_body = rho_ty } where no_tvs = case tele of HsForAllVis { hsf_vis_bndrs = bndrs } -> null bndrs HsForAllInvis { hsf_invis_bndrs = bndrs } -> null bndrs -- | If passed an empty 'TH.Cxt', this simply returns the third argument -- (an 'LHsType'). Otherwise, return an 'HsQualTy' using the provided -- 'LHsContext' and 'LHsType'. -- It's important that we don't build an HsQualTy if the context is empty, -- as the pretty-printer for HsType _always_ prints contexts, even if -- they're empty. See #13183. mkHsQualTy :: TH.Cxt -- ^ The original Template Haskell context -> SrcSpanAnnA -- ^ The location of the returned 'LHsType' if it needs an -- explicit context -> LHsContext GhcPs -- ^ The converted context -> LHsType GhcPs -- ^ The converted tau type -> LHsType GhcPs -- ^ The complete type, qualified with a context if necessary mkHsQualTy ctxt loc ctxt' ty | null ctxt = ty | otherwise = L loc $ HsQualTy { hst_xqual = noExtField , hst_ctxt = ctxt' , hst_body = ty } -- | @'mkHsContextMaybe' lc@ returns 'Nothing' if @lc@ is empty and @'Just' lc@ -- otherwise. -- -- This is much like 'mkHsQualTy', except that it returns a -- @'Maybe' ('LHsContext' 'GhcPs')@. This is used specifically for constructing -- superclasses, datatype contexts (#20011), and contexts in GADT constructor -- types (#20590). We wish to avoid using @'Just' []@ in the case of an empty -- contexts, as the pretty-printer always prints 'Just' contexts, even if -- they're empty. mkHsContextMaybe :: LHsContext GhcPs -> Maybe (LHsContext GhcPs) mkHsContextMaybe lctxt@(L _ ctxt) | null ctxt = Nothing | otherwise = Just lctxt mkHsOuterFamEqnTyVarBndrs :: Maybe [LHsTyVarBndr () GhcPs] -> HsOuterFamEqnTyVarBndrs GhcPs mkHsOuterFamEqnTyVarBndrs = maybe mkHsOuterImplicit (mkHsOuterExplicit noAnn) -------------------------------------------------------------------- -- Turning Name back into RdrName -------------------------------------------------------------------- -- variable names vNameN, cNameN, vcNameN, tNameN, tconNameN :: TH.Name -> CvtM (LocatedN RdrName) vNameL :: TH.Name -> CvtM (LocatedA RdrName) vName, cName, vcName, tName, tconName :: TH.Name -> CvtM RdrName -- Variable names vNameN n = wrapLN (vName n) vNameL n = wrapLA (vName n) vName n = cvtName OccName.varName n -- Constructor function names; this is Haskell source, hence srcDataName cNameN n = wrapLN (cName n) cName n = cvtName OccName.dataName n -- Variable *or* constructor names; check by looking at the first char vcNameN n = wrapLN (vcName n) vcName n = if isVarName n then vName n else cName n -- Type variable names tNameN n = wrapLN (tName n) tName n = cvtName OccName.tvName n -- Type Constructor names tconNameN n = wrapLN (tconName n) tconName n = cvtName OccName.tcClsName n ipName :: String -> CvtM HsIPName ipName n = do { unless (okVarOcc n) (failWith (badOcc OccName.varName n)) ; return (HsIPName (fsLit n)) } cvtName :: OccName.NameSpace -> TH.Name -> CvtM RdrName cvtName ctxt_ns (TH.Name occ flavour) | not (okOcc ctxt_ns occ_str) = failWith (badOcc ctxt_ns occ_str) | otherwise = do { loc <- getL ; let rdr_name = thRdrName loc ctxt_ns occ_str flavour ; force rdr_name ; return rdr_name } where occ_str = TH.occString occ okOcc :: OccName.NameSpace -> String -> Bool okOcc ns str | OccName.isVarNameSpace ns = okVarOcc str | OccName.isDataConNameSpace ns = okConOcc str | otherwise = okTcOcc str -- Determine the name space of a name in a type -- isVarName :: TH.Name -> Bool isVarName (TH.Name occ _) = case TH.occString occ of "" -> False (c:_) -> startsVarId c || startsVarSym c badOcc :: OccName.NameSpace -> String -> SDoc badOcc ctxt_ns occ = text "Illegal" <+> pprNameSpace ctxt_ns <+> text "name:" <+> quotes (text occ) thRdrName :: SrcSpan -> OccName.NameSpace -> String -> TH.NameFlavour -> RdrName -- This turns a TH Name into a RdrName; used for both binders and occurrences -- See Note [Binders in Template Haskell] -- The passed-in name space tells what the context is expecting; -- use it unless the TH name knows what name-space it comes -- from, in which case use the latter -- -- We pass in a SrcSpan (gotten from the monad) because this function -- is used for *binders* and if we make an Exact Name we want it -- to have a binding site inside it. (cf #5434) -- -- ToDo: we may generate silly RdrNames, by passing a name space -- that doesn't match the string, like VarName ":+", -- which will give confusing error messages later -- -- The strict applications ensure that any buried exceptions get forced thRdrName loc ctxt_ns th_occ th_name = case th_name of TH.NameG th_ns pkg mod -> thOrigRdrName th_occ th_ns pkg mod TH.NameQ mod -> (mkRdrQual $! mk_mod mod) $! occ TH.NameL uniq -> nameRdrName $! (((Name.mkInternalName $! mk_uniq (fromInteger uniq)) $! occ) loc) TH.NameU uniq -> nameRdrName $! (((Name.mkSystemNameAt $! mk_uniq (fromInteger uniq)) $! occ) loc) TH.NameS | Just name <- isBuiltInOcc_maybe occ -> nameRdrName $! name | otherwise -> mkRdrUnqual $! occ -- We check for built-in syntax here, because the TH -- user might have written a (NameS "(,,)"), for example where occ :: OccName.OccName occ = mk_occ ctxt_ns th_occ -- Return an unqualified exact RdrName if we're dealing with built-in syntax. -- See #13776. thOrigRdrName :: String -> TH.NameSpace -> PkgName -> ModName -> RdrName thOrigRdrName occ th_ns pkg mod = let occ' = mk_occ (mk_ghc_ns th_ns) occ in case isBuiltInOcc_maybe occ' of Just name -> nameRdrName name Nothing -> (mkOrig $! (mkModule (mk_pkg pkg) (mk_mod mod))) $! occ' thRdrNameGuesses :: TH.Name -> [RdrName] thRdrNameGuesses (TH.Name occ flavour) -- This special case for NameG ensures that we don't generate duplicates in the output list | TH.NameG th_ns pkg mod <- flavour = [ thOrigRdrName occ_str th_ns pkg mod] | otherwise = [ thRdrName noSrcSpan gns occ_str flavour | gns <- guessed_nss] where -- guessed_ns are the name spaces guessed from looking at the TH name guessed_nss | isLexCon (mkFastString occ_str) = [OccName.tcName, OccName.dataName] | otherwise = [OccName.varName, OccName.tvName] occ_str = TH.occString occ -- The packing and unpacking is rather turgid :-( mk_occ :: OccName.NameSpace -> String -> OccName.OccName mk_occ ns occ = OccName.mkOccName ns occ mk_ghc_ns :: TH.NameSpace -> OccName.NameSpace mk_ghc_ns TH.DataName = OccName.dataName mk_ghc_ns TH.TcClsName = OccName.tcClsName mk_ghc_ns TH.VarName = OccName.varName mk_mod :: TH.ModName -> ModuleName mk_mod mod = mkModuleName (TH.modString mod) mk_pkg :: TH.PkgName -> Unit mk_pkg pkg = stringToUnit (TH.pkgString pkg) mk_uniq :: Int -> Unique mk_uniq u = mkUniqueGrimily u {- Note [Binders in Template Haskell] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Consider this TH term construction: do { x1 <- TH.newName "x" -- newName :: String -> Q TH.Name ; x2 <- TH.newName "x" -- Builds a NameU ; x3 <- TH.newName "x" ; let x = mkName "x" -- mkName :: String -> TH.Name -- Builds a NameS ; return (LamE (..pattern [x1,x2]..) $ LamE (VarPat x3) $ ..tuple (x1,x2,x3,x)) } It represents the term \[x1,x2]. \x3. (x1,x2,x3,x) a) We don't want to complain about "x" being bound twice in the pattern [x1,x2] b) We don't want x3 to shadow the x1,x2 c) We *do* want 'x' (dynamically bound with mkName) to bind to the innermost binding of "x", namely x3. d) When pretty printing, we want to print a unique with x1,x2 etc, else they'll all print as "x" which isn't very helpful When we convert all this to HsSyn, the TH.Names are converted with thRdrName. To achieve (b) we want the binders to be Exact RdrNames. Achieving (a) is a bit awkward, because - We must check for duplicate and shadowed names on Names, not RdrNames, *after* renaming. See Note [Collect binders only after renaming] in GHC.Hs.Utils - But to achieve (a) we must distinguish between the Exact RdrNames arising from TH and the Unqual RdrNames that would come from a user writing \[x,x] -> blah So in Convert.thRdrName we translate TH Name RdrName -------------------------------------------------------- NameU (arising from newName) --> Exact (Name{ System }) NameS (arising from mkName) --> Unqual Notice that the NameUs generate *System* Names. Then, when figuring out shadowing and duplicates, we can filter out System Names. This use of System Names fits with other uses of System Names, eg for temporary variables "a". Since there are lots of things called "a" we usually want to print the name with the unique, and that is indeed the way System Names are printed. There's a small complication of course; see Note [Looking up Exact RdrNames] in GHC.Rename.Env. -} {- Note [Pattern synonym type signatures and Template Haskell] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ In general, the type signature of a pattern synonym pattern P x1 x2 .. xn = is of the form forall univs. reqs => forall exis. provs => t1 -> t2 -> ... -> tn -> t with the following parts: 1) the (possibly empty lists of) universally quantified type variables `univs` and required constraints `reqs` on them. 2) the (possibly empty lists of) existentially quantified type variables `exis` and the provided constraints `provs` on them. 3) the types `t1`, `t2`, .., `tn` of the pattern synonym's arguments x1, x2, .., xn, respectively 4) the type `t` of , mentioning only universals from `univs`. Due to the two forall quantifiers and constraint contexts (either of which might be empty), pattern synonym type signatures are treated specially in `GHC.HsToCore.Quote`, `GHC.ThToHs`, and `GHC.Tc.Gen.Splice`: (a) When desugaring a pattern synonym from HsSyn to TH.Dec in `GHC.HsToCore.Quote`, we represent its *full* type signature in TH, i.e.: ForallT univs reqs (ForallT exis provs ty) (where ty is the AST representation of t1 -> t2 -> ... -> tn -> t) (b) When converting pattern synonyms from TH.Dec to HsSyn in `GHC.ThToHs`, we convert their TH type signatures back to an appropriate Haskell pattern synonym type of the form forall univs. reqs => forall exis. provs => t1 -> t2 -> ... -> tn -> t where initial empty `univs` type variables or an empty `reqs` constraint context are represented *explicitly* as `() =>`. (c) When reifying a pattern synonym in `GHC.Tc.Gen.Splice`, we always return its *full* type, i.e.: ForallT univs reqs (ForallT exis provs ty) (where ty is the AST representation of t1 -> t2 -> ... -> tn -> t) The key point is to always represent a pattern synonym's *full* type in cases (a) and (c) to make it clear which of the two forall quantifiers and/or constraint contexts are specified, and which are not. See GHC's user's guide on pattern synonyms for more information about pattern synonym type signatures. -}