{-# LANGUAGE CPP, PatternGuards, TypeFamilies #-} ----------------------------------------------------------------------------- -- | -- Module : Haddock.Convert -- Copyright : (c) Isaac Dupree 2009, -- License : BSD-like -- -- Maintainer : haddock@projects.haskell.org -- Stability : experimental -- Portability : portable -- -- Conversion between TyThing and HsDecl. This functionality may be moved into -- GHC at some point. ----------------------------------------------------------------------------- module Haddock.Convert ( tyThingToLHsDecl, synifyInstHead, synifyFamInst, PrintRuntimeReps(..), ) where import GHC.Data.Bag ( emptyBag ) import GHC.Types.Basic ( TupleSort(..), DefMethSpec(..), TopLevelFlag(..) ) import GHC.Types.SourceText (SourceText(..)) import GHC.Types.Fixity (LexicalFixity(..)) import GHC.Core.Class import GHC.Core.Coercion.Axiom import GHC.Core.ConLike import Data.Either (lefts, rights) import GHC.Core.DataCon import GHC.Core.FamInstEnv import GHC.Hs import GHC.Types.TyThing import GHC.Types.Name import GHC.Types.Name.Set ( emptyNameSet ) import GHC.Types.Name.Reader ( mkVarUnqual ) import GHC.Core.PatSyn import GHC.Tc.Utils.TcType import GHC.Core.TyCon import GHC.Core.Type import GHC.Core.TyCo.Rep import GHC.Builtin.Types.Prim ( alphaTyVars ) import GHC.Builtin.Types ( eqTyConName, listTyConName, liftedTypeKindTyConName , unitTy, promotedNilDataCon, promotedConsDataCon ) import GHC.Builtin.Names ( hasKey, eqTyConKey, ipClassKey, tYPETyConKey , liftedDataConKey, boxedRepDataConKey ) import GHC.Types.Unique ( getUnique ) import GHC.Utils.Misc ( chkAppend, dropList, equalLength , filterByList, filterOut ) import GHC.Utils.Panic.Plain ( assert ) import GHC.Types.Var import GHC.Types.Var.Set import GHC.Types.SrcLoc import Haddock.Types import Haddock.Interface.Specialize import Haddock.GhcUtils ( orderedFVs, defaultRuntimeRepVars, mkEmptySigType ) import Data.Maybe ( catMaybes, mapMaybe, maybeToList ) -- | Whether or not to default 'RuntimeRep' variables to 'LiftedRep'. Check -- out Note [Defaulting RuntimeRep variables] in GHC.Iface.Type for the -- motivation. data PrintRuntimeReps = ShowRuntimeRep | HideRuntimeRep deriving Show -- the main function here! yay! tyThingToLHsDecl :: PrintRuntimeReps -> TyThing -> Either ErrMsg ([ErrMsg], (HsDecl GhcRn)) tyThingToLHsDecl prr t = case t of -- ids (functions and zero-argument a.k.a. CAFs) get a type signature. -- Including built-in functions like seq. -- foreign-imported functions could be represented with ForD -- instead of SigD if we wanted... -- -- in a future code version we could turn idVarDetails = foreign-call -- into a ForD instead of a SigD if we wanted. Haddock doesn't -- need to care. AnId i -> allOK $ SigD noExtField (synifyIdSig prr ImplicitizeForAll [] i) -- type-constructors (e.g. Maybe) are complicated, put the definition -- later in the file (also it's used for class associated-types too.) ATyCon tc | Just cl <- tyConClass_maybe tc -- classes are just a little tedious -> let extractFamilyDecl :: TyClDecl a -> Either ErrMsg (FamilyDecl a) extractFamilyDecl (FamDecl _ d) = return d extractFamilyDecl _ = Left "tyThingToLHsDecl: impossible associated tycon" cvt :: HsTyVarBndr flag GhcRn -> HsType GhcRn -- Without this signature, we trigger GHC#18932 cvt (UserTyVar _ _ n) = HsTyVar noAnn NotPromoted n cvt (KindedTyVar _ _ (L name_loc n) kind) = HsKindSig noAnn (L (na2la name_loc) (HsTyVar noAnn NotPromoted (L name_loc n))) kind -- | Convert a LHsTyVarBndr to an equivalent LHsType. hsLTyVarBndrToType :: LHsTyVarBndr flag GhcRn -> LHsType GhcRn hsLTyVarBndrToType = mapLoc cvt extractFamDefDecl :: FamilyDecl GhcRn -> Type -> TyFamDefltDecl GhcRn extractFamDefDecl fd rhs = TyFamInstDecl noAnn $ FamEqn { feqn_ext = noAnn , feqn_tycon = fdLName fd , feqn_bndrs = HsOuterImplicit{hso_ximplicit = hsq_ext (fdTyVars fd)} , feqn_pats = map (HsValArg . hsLTyVarBndrToType) $ hsq_explicit $ fdTyVars fd , feqn_fixity = fdFixity fd , feqn_rhs = synifyType WithinType [] rhs } extractAtItem :: ClassATItem -> Either ErrMsg (LFamilyDecl GhcRn, Maybe (LTyFamDefltDecl GhcRn)) extractAtItem (ATI at_tc def) = do tyDecl <- synifyTyCon prr Nothing at_tc famDecl <- extractFamilyDecl tyDecl let defEqnTy = fmap (noLocA . extractFamDefDecl famDecl . fst) def pure (noLocA famDecl, defEqnTy) atTyClDecls = map extractAtItem (classATItems cl) (atFamDecls, atDefFamDecls) = unzip (rights atTyClDecls) vs = tyConVisibleTyVars (classTyCon cl) in withErrs (lefts atTyClDecls) . TyClD noExtField $ ClassDecl { tcdCtxt = Just $ synifyCtx (classSCTheta cl) , tcdLName = synifyNameN cl , tcdTyVars = synifyTyVars vs , tcdFixity = synifyFixity cl , tcdFDs = map (\ (l,r) -> noLocA (FunDep noAnn (map (noLocA . getName) l) (map (noLocA . getName) r)) ) $ snd $ classTvsFds cl , tcdSigs = noLocA (MinimalSig (noAnn, NoSourceText) . noLocA . fmap noLocA $ classMinimalDef cl) : [ noLocA tcdSig | clsOp <- classOpItems cl , tcdSig <- synifyTcIdSig vs clsOp ] , tcdMeths = emptyBag --ignore default method definitions, they don't affect signature -- class associated-types are a subset of TyCon: , tcdATs = atFamDecls , tcdATDefs = catMaybes atDefFamDecls , tcdDocs = [] --we don't have any docs at this point , tcdCExt = emptyNameSet } | otherwise -> synifyTyCon prr Nothing tc >>= allOK . TyClD noExtField -- type-constructors (e.g. Maybe) are complicated, put the definition -- later in the file (also it's used for class associated-types too.) ACoAxiom ax -> synifyAxiom ax >>= allOK -- a data-constructor alone just gets rendered as a function: AConLike (RealDataCon dc) -> allOK $ SigD noExtField (TypeSig noAnn [synifyNameN dc] (synifySigWcType ImplicitizeForAll [] (dataConWrapperType dc))) AConLike (PatSynCon ps) -> allOK . SigD noExtField $ PatSynSig noAnn [synifyNameN ps] (synifyPatSynSigType ps) where withErrs e x = return (e, x) allOK x = return (mempty, x) synifyAxBranch :: TyCon -> CoAxBranch -> TyFamInstEqn GhcRn synifyAxBranch tc (CoAxBranch { cab_tvs = tkvs, cab_lhs = args, cab_rhs = rhs }) = let name = synifyNameN tc args_types_only = filterOutInvisibleTypes tc args typats = map (synifyType WithinType []) args_types_only annot_typats = zipWith3 annotHsType args_poly args_types_only typats hs_rhs = synifyType WithinType [] rhs outer_bndrs = HsOuterImplicit{hso_ximplicit = map tyVarName tkvs} -- TODO: this must change eventually in FamEqn { feqn_ext = noAnn , feqn_tycon = name , feqn_bndrs = outer_bndrs , feqn_pats = map HsValArg annot_typats , feqn_fixity = synifyFixity name , feqn_rhs = hs_rhs } where args_poly = tyConArgsPolyKinded tc synifyAxiom :: CoAxiom br -> Either ErrMsg (HsDecl GhcRn) synifyAxiom ax@(CoAxiom { co_ax_tc = tc }) | isOpenTypeFamilyTyCon tc , Just branch <- coAxiomSingleBranch_maybe ax = return $ InstD noExtField $ TyFamInstD noExtField $ TyFamInstDecl { tfid_xtn = noAnn, tfid_eqn = synifyAxBranch tc branch } | Just ax' <- isClosedSynFamilyTyConWithAxiom_maybe tc , getUnique ax' == getUnique ax -- without the getUniques, type error = synifyTyCon ShowRuntimeRep (Just ax) tc >>= return . TyClD noExtField | otherwise = Left "synifyAxiom: closed/open family confusion" -- | Turn type constructors into data declarations, type families, or type synonyms synifyTyCon :: PrintRuntimeReps -> Maybe (CoAxiom br) -- ^ RHS of type synonym -> TyCon -- ^ type constructor to convert -> Either ErrMsg (TyClDecl GhcRn) synifyTyCon prr _coax tc | isFunTyCon tc || isPrimTyCon tc = return $ DataDecl { tcdLName = synifyNameN tc , tcdTyVars = HsQTvs { hsq_ext = [] -- No kind polymorphism , hsq_explicit = zipWith mk_hs_tv (map scaledThing tyVarKinds) alphaTyVars --a, b, c... which are unfortunately all kind * } , tcdFixity = synifyFixity tc , tcdDataDefn = HsDataDefn { dd_ext = noExtField , dd_ND = DataType -- arbitrary lie, they are neither -- algebraic data nor newtype: , dd_ctxt = Nothing , dd_cType = Nothing , dd_kindSig = synifyDataTyConReturnKind tc -- we have their kind accurately: , dd_cons = [] -- No constructors , dd_derivs = [] } , tcdDExt = DataDeclRn False emptyNameSet } where -- tyConTyVars doesn't work on fun/prim, but we can make them up: mk_hs_tv realKind fakeTyVar | isLiftedTypeKind realKind = noLocA $ UserTyVar noAnn () (noLocA (getName fakeTyVar)) | otherwise = noLocA $ KindedTyVar noAnn () (noLocA (getName fakeTyVar)) (synifyKindSig realKind) conKind = defaultType prr (tyConKind tc) tyVarKinds = fst . splitFunTys . snd . splitInvisPiTys $ conKind synifyTyCon _prr _coax tc | Just flav <- famTyConFlav_maybe tc = case flav of -- Type families OpenSynFamilyTyCon -> mkFamDecl OpenTypeFamily ClosedSynFamilyTyCon mb | Just (CoAxiom { co_ax_branches = branches }) <- mb -> mkFamDecl $ ClosedTypeFamily $ Just $ map (noLocA . synifyAxBranch tc) (fromBranches branches) | otherwise -> mkFamDecl $ ClosedTypeFamily $ Just [] BuiltInSynFamTyCon {} -> mkFamDecl $ ClosedTypeFamily $ Just [] AbstractClosedSynFamilyTyCon {} -> mkFamDecl $ ClosedTypeFamily Nothing DataFamilyTyCon {} -> mkFamDecl DataFamily where resultVar = famTcResVar tc mkFamDecl i = return $ FamDecl noExtField $ FamilyDecl { fdExt = noAnn , fdInfo = i , fdTopLevel = TopLevel , fdLName = synifyNameN tc , fdTyVars = synifyTyVars (tyConVisibleTyVars tc) , fdFixity = synifyFixity tc , fdResultSig = synifyFamilyResultSig resultVar (tyConResKind tc) , fdInjectivityAnn = synifyInjectivityAnn resultVar (tyConTyVars tc) (tyConInjectivityInfo tc) } synifyTyCon _prr coax tc | Just ty <- synTyConRhs_maybe tc = return $ SynDecl { tcdSExt = emptyNameSet , tcdLName = synifyNameN tc , tcdTyVars = synifyTyVars (tyConVisibleTyVars tc) , tcdFixity = synifyFixity tc , tcdRhs = synifyType WithinType [] ty } | otherwise = -- (closed) newtype and data let alg_nd = if isNewTyCon tc then NewType else DataType alg_ctx = synifyCtx (tyConStupidTheta tc) name = case coax of Just a -> synifyNameN a -- Data families are named according to their -- CoAxioms, not their TyCons _ -> synifyNameN tc tyvars = synifyTyVars (tyConVisibleTyVars tc) kindSig = synifyDataTyConReturnKind tc -- The data constructors. -- -- Any data-constructors not exported from the module that *defines* the -- type will not (cannot) be included. -- -- Very simple constructors, Haskell98 with no existentials or anything, -- probably look nicer in non-GADT syntax. In source code, all constructors -- must be declared with the same (GADT vs. not) syntax, and it probably -- is less confusing to follow that principle for the documentation as well. -- -- There is no sensible infix-representation for GADT-syntax constructor -- declarations. They cannot be made in source code, but we could end up -- with some here in the case where some constructors use existentials. -- That seems like an acceptable compromise (they'll just be documented -- in prefix position), since, otherwise, the logic (at best) gets much more -- complicated. (would use dataConIsInfix.) use_gadt_syntax = isGadtSyntaxTyCon tc consRaw = map (synifyDataCon use_gadt_syntax) (tyConDataCons tc) cons = rights consRaw -- "deriving" doesn't affect the signature, no need to specify any. alg_deriv = [] defn = HsDataDefn { dd_ext = noExtField , dd_ND = alg_nd , dd_ctxt = Just alg_ctx , dd_cType = Nothing , dd_kindSig = kindSig , dd_cons = cons , dd_derivs = alg_deriv } in case lefts consRaw of [] -> return $ DataDecl { tcdLName = name, tcdTyVars = tyvars , tcdFixity = synifyFixity name , tcdDataDefn = defn , tcdDExt = DataDeclRn False emptyNameSet } dataConErrs -> Left $ unlines dataConErrs -- | In this module, every TyCon being considered has come from an interface -- file. This means that when considering a data type constructor such as: -- -- > data Foo (w :: *) (m :: * -> *) (a :: *) -- -- Then its tyConKind will be (* -> (* -> *) -> * -> *). But beware! We are -- also rendering the type variables of Foo, so if we synify the tyConKind of -- Foo in full, we will end up displaying this in Haddock: -- -- > data Foo (w :: *) (m :: * -> *) (a :: *) -- > :: * -> (* -> *) -> * -> * -- -- Which is entirely wrong (#548). We only want to display the /return/ kind, -- which this function obtains. synifyDataTyConReturnKind :: TyCon -> Maybe (LHsKind GhcRn) synifyDataTyConReturnKind tc | isLiftedTypeKind ret_kind = Nothing -- Don't bother displaying :: * | otherwise = Just (synifyKindSig ret_kind) where ret_kind = tyConResKind tc synifyInjectivityAnn :: Maybe Name -> [TyVar] -> Injectivity -> Maybe (LInjectivityAnn GhcRn) synifyInjectivityAnn Nothing _ _ = Nothing synifyInjectivityAnn _ _ NotInjective = Nothing synifyInjectivityAnn (Just lhs) tvs (Injective inj) = let rhs = map (noLocA . tyVarName) (filterByList inj tvs) in Just $ noLocA $ InjectivityAnn noAnn (noLocA lhs) rhs synifyFamilyResultSig :: Maybe Name -> Kind -> LFamilyResultSig GhcRn synifyFamilyResultSig Nothing kind | isLiftedTypeKind kind = noLocA $ NoSig noExtField | otherwise = noLocA $ KindSig noExtField (synifyKindSig kind) synifyFamilyResultSig (Just name) kind = noLocA $ TyVarSig noExtField (noLocA $ KindedTyVar noAnn () (noLocA name) (synifyKindSig kind)) -- User beware: it is your responsibility to pass True (use_gadt_syntax) -- for any constructor that would be misrepresented by omitting its -- result-type. -- But you might want pass False in simple enough cases, -- if you think it looks better. synifyDataCon :: Bool -> DataCon -> Either ErrMsg (LConDecl GhcRn) synifyDataCon use_gadt_syntax dc = let -- dataConIsInfix allegedly tells us whether it was declared with -- infix *syntax*. use_infix_syntax = dataConIsInfix dc use_named_field_syntax = not (null field_tys) name = synifyNameN dc -- con_qvars means a different thing depending on gadt-syntax (_univ_tvs, ex_tvs, _eq_spec, theta, arg_tys, res_ty) = dataConFullSig dc user_tvbndrs = dataConUserTyVarBinders dc -- Used for GADT data constructors outer_bndrs | null user_tvbndrs = HsOuterImplicit { hso_ximplicit = [] } | otherwise = HsOuterExplicit { hso_xexplicit = noExtField , hso_bndrs = map synifyTyVarBndr user_tvbndrs } -- skip any EqTheta, use 'orig'inal syntax ctx | null theta = Nothing | otherwise = Just $ synifyCtx theta linear_tys = zipWith (\ty bang -> let tySyn = synifyType WithinType [] (scaledThing ty) in case bang of (HsSrcBang _ NoSrcUnpack NoSrcStrict) -> tySyn bang' -> noLocA $ HsBangTy noAnn bang' tySyn) arg_tys (dataConSrcBangs dc) field_tys = zipWith con_decl_field (dataConFieldLabels dc) linear_tys con_decl_field fl synTy = noLocA $ ConDeclField noAnn [noLocA $ FieldOcc (flSelector fl) (noLocA $ mkVarUnqual $ flLabel fl)] synTy Nothing mk_h98_arg_tys :: Either ErrMsg (HsConDeclH98Details GhcRn) mk_h98_arg_tys = case (use_named_field_syntax, use_infix_syntax) of (True,True) -> Left "synifyDataCon: contradiction!" (True,False) -> return $ RecCon (noLocA field_tys) (False,False) -> return $ PrefixCon noTypeArgs (map hsUnrestricted linear_tys) (False,True) -> case linear_tys of [a,b] -> return $ InfixCon (hsUnrestricted a) (hsUnrestricted b) _ -> Left "synifyDataCon: infix with non-2 args?" mk_gadt_arg_tys :: HsConDeclGADTDetails GhcRn mk_gadt_arg_tys | use_named_field_syntax = RecConGADT (noLocA field_tys) noHsUniTok | otherwise = PrefixConGADT (map hsUnrestricted linear_tys) -- finally we get synifyDataCon's result! in if use_gadt_syntax then do let hat = mk_gadt_arg_tys return $ noLocA $ ConDeclGADT { con_g_ext = noAnn , con_names = [name] , con_dcolon = noHsUniTok , con_bndrs = noLocA outer_bndrs , con_mb_cxt = ctx , con_g_args = hat , con_res_ty = synifyType WithinType [] res_ty , con_doc = Nothing } else do hat <- mk_h98_arg_tys return $ noLocA $ ConDeclH98 { con_ext = noAnn , con_name = name , con_forall = False , con_ex_tvs = map (synifyTyVarBndr . (mkTyCoVarBinder InferredSpec)) ex_tvs , con_mb_cxt = ctx , con_args = hat , con_doc = Nothing } synifyNameN :: NamedThing n => n -> LocatedN Name synifyNameN n = L (noAnnSrcSpan $ srcLocSpan (getSrcLoc n)) (getName n) -- synifyName :: NamedThing n => n -> LocatedA Name -- synifyName n = L (noAnnSrcSpan $ srcLocSpan (getSrcLoc n)) (getName n) -- | Guess the fixity of a something with a name. This isn't quite right, since -- a user can always declare an infix name in prefix form or a prefix name in -- infix form. Unfortunately, that is not something we can usually reconstruct. synifyFixity :: NamedThing n => n -> LexicalFixity synifyFixity n | isSymOcc (getOccName n) = Infix | otherwise = Prefix synifyIdSig :: PrintRuntimeReps -- ^ are we printing tyvars of kind 'RuntimeRep'? -> SynifyTypeState -- ^ what to do with a 'forall' -> [TyVar] -- ^ free variables in the type to convert -> Id -- ^ the 'Id' from which to get the type signature -> Sig GhcRn synifyIdSig prr s vs i = TypeSig noAnn [synifyNameN i] (synifySigWcType s vs t) where t = defaultType prr (varType i) -- | Turn a 'ClassOpItem' into a list of signatures. The list returned is going -- to contain the synified 'ClassOpSig' as well (when appropriate) a default -- 'ClassOpSig'. synifyTcIdSig :: [TyVar] -> ClassOpItem -> [Sig GhcRn] synifyTcIdSig vs (i, dm) = [ ClassOpSig noAnn False [synifyNameN i] (mainSig (varType i)) ] ++ [ ClassOpSig noAnn True [noLocA dn] (defSig dt) | Just (dn, GenericDM dt) <- [dm] ] where mainSig t = synifySigType DeleteTopLevelQuantification vs t defSig t = synifySigType ImplicitizeForAll vs t synifyCtx :: [PredType] -> LHsContext GhcRn synifyCtx ts = noLocA ( map (synifyType WithinType []) ts) synifyTyVars :: [TyVar] -> LHsQTyVars GhcRn synifyTyVars ktvs = HsQTvs { hsq_ext = [] , hsq_explicit = map synifyTyVar ktvs } synifyTyVar :: TyVar -> LHsTyVarBndr () GhcRn synifyTyVar = synify_ty_var emptyVarSet () synifyTyVarBndr :: VarBndr TyVar flag -> LHsTyVarBndr flag GhcRn synifyTyVarBndr = synifyTyVarBndr' emptyVarSet synifyTyVarBndr' :: VarSet -> VarBndr TyVar flag -> LHsTyVarBndr flag GhcRn synifyTyVarBndr' no_kinds (Bndr tv spec) = synify_ty_var no_kinds spec tv -- | Like 'synifyTyVarBndr', but accepts a set of variables for which to omit kind -- signatures (even if they don't have the lifted type kind). synify_ty_var :: VarSet -> flag -> TyVar -> LHsTyVarBndr flag GhcRn synify_ty_var no_kinds flag tv | isLiftedTypeKind kind || tv `elemVarSet` no_kinds = noLocA (UserTyVar noAnn flag (noLocA name)) | otherwise = noLocA (KindedTyVar noAnn flag (noLocA name) (synifyKindSig kind)) where kind = tyVarKind tv name = getName tv -- | Annotate (with HsKingSig) a type if the first parameter is True -- and if the type contains a free variable. -- This is used to synify type patterns for poly-kinded tyvars in -- synifying class and type instances. annotHsType :: Bool -- True <=> annotate -> Type -> LHsType GhcRn -> LHsType GhcRn -- tiny optimization: if the type is annotated, don't annotate again. annotHsType _ _ hs_ty@(L _ (HsKindSig {})) = hs_ty annotHsType True ty hs_ty | not $ isEmptyVarSet $ filterVarSet isTyVar $ tyCoVarsOfType ty = let ki = typeKind ty hs_ki = synifyType WithinType [] ki in noLocA (HsKindSig noAnn hs_ty hs_ki) annotHsType _ _ hs_ty = hs_ty -- | For every argument type that a type constructor accepts, -- report whether or not the argument is poly-kinded. This is used to -- eventually feed into 'annotThType'. tyConArgsPolyKinded :: TyCon -> [Bool] tyConArgsPolyKinded tc = map (is_poly_ty . tyVarKind) tc_vis_tvs ++ map (is_poly_ty . tyCoBinderType) tc_res_kind_vis_bndrs ++ repeat True where is_poly_ty :: Type -> Bool is_poly_ty ty = not $ isEmptyVarSet $ filterVarSet isTyVar $ tyCoVarsOfType ty tc_vis_tvs :: [TyVar] tc_vis_tvs = tyConVisibleTyVars tc tc_res_kind_vis_bndrs :: [TyCoBinder] tc_res_kind_vis_bndrs = filter isVisibleBinder $ fst $ splitPiTys $ tyConResKind tc --states of what to do with foralls: data SynifyTypeState = WithinType -- ^ normal situation. This is the safe one to use if you don't -- quite understand what's going on. | ImplicitizeForAll -- ^ beginning of a function definition, in which, to make it look -- less ugly, those rank-1 foralls (without kind annotations) are made -- implicit. | DeleteTopLevelQuantification -- ^ because in class methods the context is added to the type -- (e.g. adding @forall a. Num a =>@ to @(+) :: a -> a -> a@) -- which is rather sensible, -- but we want to restore things to the source-syntax situation where -- the defining class gets to quantify all its functions for free! synifySigType :: SynifyTypeState -> [TyVar] -> Type -> LHsSigType GhcRn -- The use of mkEmptySigType (which uses empty binders in OuterImplicit) -- is a bit suspicious; what if the type has free variables? synifySigType s vs ty = mkEmptySigType (synifyType s vs ty) synifySigWcType :: SynifyTypeState -> [TyVar] -> Type -> LHsSigWcType GhcRn -- Ditto (see synifySigType) synifySigWcType s vs ty = mkEmptyWildCardBndrs (mkEmptySigType (synifyType s vs ty)) synifyPatSynSigType :: PatSyn -> LHsSigType GhcRn -- Ditto (see synifySigType) synifyPatSynSigType ps = mkEmptySigType (synifyPatSynType ps) -- | Depending on the first argument, try to default all type variables of kind -- 'RuntimeRep' to 'LiftedType'. defaultType :: PrintRuntimeReps -> Type -> Type defaultType ShowRuntimeRep = id defaultType HideRuntimeRep = defaultRuntimeRepVars -- | Convert a core type into an 'HsType'. synifyType :: SynifyTypeState -- ^ what to do with a 'forall' -> [TyVar] -- ^ free variables in the type to convert -> Type -- ^ the type to convert -> LHsType GhcRn synifyType _ _ (TyVarTy tv) = noLocA $ HsTyVar noAnn NotPromoted $ noLocA (getName tv) synifyType _ vs (TyConApp tc tys) = maybe_sig res_ty where res_ty :: LHsType GhcRn res_ty -- Use */# instead of TYPE 'Lifted/TYPE 'Unlifted (#473) | tc `hasKey` tYPETyConKey , [TyConApp rep [TyConApp lev []]] <- tys , rep `hasKey` boxedRepDataConKey , lev `hasKey` liftedDataConKey = noLocA (HsTyVar noAnn NotPromoted (noLocA liftedTypeKindTyConName)) -- Use non-prefix tuple syntax where possible, because it looks nicer. | Just sort <- tyConTuple_maybe tc , tyConArity tc == tys_len = noLocA $ HsTupleTy noAnn (case sort of BoxedTuple -> HsBoxedOrConstraintTuple ConstraintTuple -> HsBoxedOrConstraintTuple UnboxedTuple -> HsUnboxedTuple) (map (synifyType WithinType vs) vis_tys) | isUnboxedSumTyCon tc = noLocA $ HsSumTy noAnn (map (synifyType WithinType vs) vis_tys) | Just dc <- isPromotedDataCon_maybe tc , isTupleDataCon dc , dataConSourceArity dc == length vis_tys = noLocA $ HsExplicitTupleTy noExtField (map (synifyType WithinType vs) vis_tys) -- ditto for lists | getName tc == listTyConName, [ty] <- vis_tys = noLocA $ HsListTy noAnn (synifyType WithinType vs ty) | tc == promotedNilDataCon, [] <- vis_tys = noLocA $ HsExplicitListTy noExtField IsPromoted [] | tc == promotedConsDataCon , [ty1, ty2] <- vis_tys = let hTy = synifyType WithinType vs ty1 in case synifyType WithinType vs ty2 of tTy | L _ (HsExplicitListTy _ IsPromoted tTy') <- stripKindSig tTy -> noLocA $ HsExplicitListTy noExtField IsPromoted (hTy : tTy') | otherwise -> noLocA $ HsOpTy noAnn IsPromoted hTy (noLocA $ getName tc) tTy -- ditto for implicit parameter tycons | tc `hasKey` ipClassKey , [name, ty] <- tys , Just x <- isStrLitTy name = noLocA $ HsIParamTy noAnn (noLocA $ HsIPName x) (synifyType WithinType vs ty) -- and equalities | tc `hasKey` eqTyConKey , [ty1, ty2] <- tys = noLocA $ HsOpTy noAnn NotPromoted (synifyType WithinType vs ty1) (noLocA eqTyConName) (synifyType WithinType vs ty2) -- and infix type operators | isSymOcc (nameOccName (getName tc)) , ty1:ty2:tys_rest <- vis_tys = mk_app_tys (HsOpTy noAnn prom (synifyType WithinType vs ty1) (noLocA $ getName tc) (synifyType WithinType vs ty2)) tys_rest -- Most TyCons: | otherwise = mk_app_tys (HsTyVar noAnn prom $ noLocA (getName tc)) vis_tys where prom = if isPromotedDataCon tc then IsPromoted else NotPromoted mk_app_tys ty_app ty_args = foldl (\t1 t2 -> noLocA $ HsAppTy noExtField t1 t2) (noLocA ty_app) (map (synifyType WithinType vs) $ filterOut isCoercionTy ty_args) tys_len = length tys vis_tys = filterOutInvisibleTypes tc tys maybe_sig :: LHsType GhcRn -> LHsType GhcRn maybe_sig ty' | tyConAppNeedsKindSig False tc tys_len = let full_kind = typeKind (mkTyConApp tc tys) full_kind' = synifyType WithinType vs full_kind in noLocA $ HsKindSig noAnn ty' full_kind' | otherwise = ty' synifyType _ vs ty@(AppTy {}) = let (ty_head, ty_args) = splitAppTys ty ty_head' = synifyType WithinType vs ty_head ty_args' = map (synifyType WithinType vs) $ filterOut isCoercionTy $ filterByList (map isVisibleArgFlag $ appTyArgFlags ty_head ty_args) ty_args in foldl (\t1 t2 -> noLocA $ HsAppTy noExtField t1 t2) ty_head' ty_args' synifyType s vs funty@(FunTy InvisArg _ _ _) = synifySigmaType s vs funty synifyType _ vs (FunTy VisArg w t1 t2) = let s1 = synifyType WithinType vs t1 s2 = synifyType WithinType vs t2 w' = synifyMult vs w in noLocA $ HsFunTy noAnn w' s1 s2 synifyType s vs forallty@(ForAllTy (Bndr _ argf) _ty) = case argf of Required -> synifyVisForAllType vs forallty Invisible _ -> synifySigmaType s vs forallty synifyType _ _ (LitTy t) = noLocA $ HsTyLit noExtField $ synifyTyLit t synifyType s vs (CastTy t _) = synifyType s vs t synifyType _ _ (CoercionTy {}) = error "synifyType:Coercion" -- | Process a 'Type' which starts with a visible @forall@ into an 'HsType' synifyVisForAllType :: [TyVar] -- ^ free variables in the type to convert -> Type -- ^ the forall type to convert -> LHsType GhcRn synifyVisForAllType vs ty = let (tvs, rho) = tcSplitForAllTysReqPreserveSynonyms ty sTvs = map synifyTyVarBndr tvs -- Figure out what the type variable order would be inferred in the -- absence of an explicit forall tvs' = orderedFVs (mkVarSet vs) [rho] in noLocA $ HsForAllTy { hst_tele = mkHsForAllVisTele noAnn sTvs , hst_xforall = noExtField , hst_body = synifyType WithinType (tvs' ++ vs) rho } -- | Process a 'Type' which starts with an invisible @forall@ or a constraint -- into an 'HsType' synifySigmaType :: SynifyTypeState -- ^ what to do with the 'forall' -> [TyVar] -- ^ free variables in the type to convert -> Type -- ^ the forall type to convert -> LHsType GhcRn synifySigmaType s vs ty = let (tvs, ctx, tau) = tcSplitSigmaTyPreserveSynonyms ty sPhi = HsQualTy { hst_ctxt = synifyCtx ctx , hst_xqual = noExtField , hst_body = synifyType WithinType (tvs' ++ vs) tau } sTy = HsForAllTy { hst_tele = mkHsForAllInvisTele noAnn sTvs , hst_xforall = noExtField , hst_body = noLocA sPhi } sTvs = map synifyTyVarBndr tvs -- Figure out what the type variable order would be inferred in the -- absence of an explicit forall tvs' = orderedFVs (mkVarSet vs) (ctx ++ [tau]) in case s of DeleteTopLevelQuantification -> synifyType ImplicitizeForAll (tvs' ++ vs) tau -- Put a forall in if there are any type variables WithinType | not (null tvs) -> noLocA sTy | otherwise -> noLocA sPhi ImplicitizeForAll -> implicitForAll [] vs tvs ctx (synifyType WithinType) tau -- | Put a forall in if there are any type variables which require -- explicit kind annotations or if the inferred type variable order -- would be different. implicitForAll :: [TyCon] -- ^ type constructors that determine their args kinds -> [TyVar] -- ^ free variables in the type to convert -> [InvisTVBinder] -- ^ type variable binders in the forall -> ThetaType -- ^ constraints right after the forall -> ([TyVar] -> Type -> LHsType GhcRn) -- ^ how to convert the inner type -> Type -- ^ inner type -> LHsType GhcRn implicitForAll tycons vs tvs ctx synInner tau | any (isHsKindedTyVar . unLoc) sTvs = noLocA sTy | tvs' /= (binderVars tvs) = noLocA sTy | otherwise = noLocA sPhi where sRho = synInner (tvs' ++ vs) tau sPhi | null ctx = unLoc sRho | otherwise = HsQualTy { hst_ctxt = synifyCtx ctx , hst_xqual = noExtField , hst_body = synInner (tvs' ++ vs) tau } sTy = HsForAllTy { hst_tele = mkHsForAllInvisTele noAnn sTvs , hst_xforall = noExtField , hst_body = noLocA sPhi } no_kinds_needed = noKindTyVars tycons tau sTvs = map (synifyTyVarBndr' no_kinds_needed) tvs -- Figure out what the type variable order would be inferred in the -- absence of an explicit forall tvs' = orderedFVs (mkVarSet vs) (ctx ++ [tau]) -- | Find the set of type variables whose kind signatures can be properly -- inferred just from their uses in the type signature. This means the type -- variable to has at least one fully applied use @f x1 x2 ... xn@ where: -- -- * @f@ has a function kind where the arguments have the same kinds -- as @x1 x2 ... xn@. -- -- * @f@ has a function kind whose final return has lifted type kind -- noKindTyVars :: [TyCon] -- ^ type constructors that determine their args kinds -> Type -- ^ type to inspect -> VarSet -- ^ set of variables whose kinds can be inferred from uses in the type noKindTyVars _ (TyVarTy var) | isLiftedTypeKind (tyVarKind var) = unitVarSet var noKindTyVars ts ty | (f, xs) <- splitAppTys ty , not (null xs) = let args = map (noKindTyVars ts) xs func = case f of TyVarTy var | (xsKinds, outKind) <- splitFunTys (tyVarKind var) , map scaledThing xsKinds `eqTypes` map typeKind xs , isLiftedTypeKind outKind -> unitVarSet var TyConApp t ks | t `elem` ts , all noFreeVarsOfType ks -> mkVarSet [ v | TyVarTy v <- xs ] _ -> noKindTyVars ts f in unionVarSets (func : args) noKindTyVars ts (ForAllTy _ t) = noKindTyVars ts t noKindTyVars ts (FunTy _ w t1 t2) = noKindTyVars ts w `unionVarSet` noKindTyVars ts t1 `unionVarSet` noKindTyVars ts t2 noKindTyVars ts (CastTy t _) = noKindTyVars ts t noKindTyVars _ _ = emptyVarSet synifyMult :: [TyVar] -> Mult -> HsArrow GhcRn synifyMult vs t = case t of One -> HsLinearArrow (HsPct1 noHsTok noHsUniTok) Many -> HsUnrestrictedArrow noHsUniTok ty -> HsExplicitMult noHsTok (synifyType WithinType vs ty) noHsUniTok synifyPatSynType :: PatSyn -> LHsType GhcRn synifyPatSynType ps = let (univ_tvs, req_theta, ex_tvs, prov_theta, arg_tys, res_ty) = patSynSigBndr ps ts = maybeToList (tyConAppTyCon_maybe res_ty) -- HACK: a HsQualTy with theta = [unitTy] will be printed as "() =>", -- i.e., an explicit empty context, which is what we need. This is not -- possible by taking theta = [], as that will print no context at all req_theta' | null req_theta , not (null prov_theta && null ex_tvs) = [unitTy] | otherwise = req_theta in implicitForAll ts [] (univ_tvs ++ ex_tvs) req_theta' (\vs -> implicitForAll ts vs [] prov_theta (synifyType WithinType)) (mkVisFunTys arg_tys res_ty) synifyTyLit :: TyLit -> HsTyLit GhcRn synifyTyLit (NumTyLit n) = HsNumTy NoSourceText n synifyTyLit (StrTyLit s) = HsStrTy NoSourceText s synifyTyLit (CharTyLit c) = HsCharTy NoSourceText c synifyKindSig :: Kind -> LHsKind GhcRn synifyKindSig k = synifyType WithinType [] k stripKindSig :: LHsType GhcRn -> LHsType GhcRn stripKindSig (L _ (HsKindSig _ t _)) = t stripKindSig t = t synifyInstHead :: ([TyVar], [PredType], Class, [Type]) -> InstHead GhcRn synifyInstHead (vs, preds, cls, types) = specializeInstHead $ InstHead { ihdClsName = getName cls , ihdTypes = map unLoc annot_ts , ihdInstType = ClassInst { clsiCtx = map (unLoc . synifyType WithinType []) preds , clsiTyVars = synifyTyVars (tyConVisibleTyVars cls_tycon) , clsiSigs = map synifyClsIdSig $ classMethods cls , clsiAssocTys = do (Right (FamDecl _ fam)) <- map (synifyTyCon HideRuntimeRep Nothing) (classATs cls) pure $ mkPseudoFamilyDecl fam } } where cls_tycon = classTyCon cls ts = filterOutInvisibleTypes cls_tycon types ts' = map (synifyType WithinType vs) ts annot_ts = zipWith3 annotHsType args_poly ts ts' args_poly = tyConArgsPolyKinded cls_tycon synifyClsIdSig = synifyIdSig ShowRuntimeRep DeleteTopLevelQuantification vs -- Convert a family instance, this could be a type family or data family synifyFamInst :: FamInst -> Bool -> Either ErrMsg (InstHead GhcRn) synifyFamInst fi opaque = do ityp' <- ityp fam_flavor return InstHead { ihdClsName = fi_fam fi , ihdTypes = map unLoc annot_ts , ihdInstType = ityp' } where ityp SynFamilyInst | opaque = return $ TypeInst Nothing ityp SynFamilyInst = return . TypeInst . Just . unLoc $ synifyType WithinType [] fam_rhs ityp (DataFamilyInst c) = DataInst <$> synifyTyCon HideRuntimeRep (Just $ famInstAxiom fi) c fam_tc = famInstTyCon fi fam_flavor = fi_flavor fi fam_lhs = fi_tys fi fam_rhs = fi_rhs fi eta_expanded_lhs -- eta-expand lhs types, because sometimes data/newtype -- instances are eta-reduced; See Trac #9692 -- See Note [Eta reduction for data family axioms] in GHC.Tc.TyCl.Instance in GHC | DataFamilyInst rep_tc <- fam_flavor = let (_, rep_tc_args) = splitTyConApp fam_rhs etad_tyvars = dropList rep_tc_args $ tyConTyVars rep_tc etad_tys = mkTyVarTys etad_tyvars eta_exp_lhs = fam_lhs `chkAppend` etad_tys in eta_exp_lhs | otherwise = fam_lhs ts = filterOutInvisibleTypes fam_tc eta_expanded_lhs synifyTypes = map (synifyType WithinType []) ts' = synifyTypes ts annot_ts = zipWith3 annotHsType args_poly ts ts' args_poly = tyConArgsPolyKinded fam_tc {- Note [Invariant: Never expand type synonyms] In haddock, we never want to expand a type synonym that may be presented to the user, as we want to keep the link to the abstraction captured in the synonym. All code in Haddock.Convert must make sure that this invariant holds. See https://github.com/haskell/haddock/issues/879 for a bug where this invariant didn't hold. -} -- | A version of 'TcType.tcSplitSigmaTy' that: -- -- 1. Preserves type synonyms. -- 2. Returns 'InvisTVBinder's instead of 'TyVar's. -- -- See Note [Invariant: Never expand type synonyms] tcSplitSigmaTyPreserveSynonyms :: Type -> ([InvisTVBinder], ThetaType, Type) tcSplitSigmaTyPreserveSynonyms ty = case tcSplitForAllTysInvisPreserveSynonyms ty of (tvs, rho) -> case tcSplitPhiTyPreserveSynonyms rho of (theta, tau) -> (tvs, theta, tau) -- | See Note [Invariant: Never expand type synonyms] tcSplitSomeForAllTysPreserveSynonyms :: (ArgFlag -> Bool) -> Type -> ([TyCoVarBinder], Type) tcSplitSomeForAllTysPreserveSynonyms argf_pred ty = split ty ty [] where split _ (ForAllTy tvb@(Bndr _ argf) ty') tvs | argf_pred argf = split ty' ty' (tvb:tvs) split orig_ty _ tvs = (reverse tvs, orig_ty) -- | See Note [Invariant: Never expand type synonyms] tcSplitForAllTysReqPreserveSynonyms :: Type -> ([ReqTVBinder], Type) tcSplitForAllTysReqPreserveSynonyms ty = let (all_bndrs, body) = tcSplitSomeForAllTysPreserveSynonyms isVisibleArgFlag ty req_bndrs = mapMaybe mk_req_bndr_maybe all_bndrs in assert ( req_bndrs `equalLength` all_bndrs) (req_bndrs, body) where mk_req_bndr_maybe :: TyCoVarBinder -> Maybe ReqTVBinder mk_req_bndr_maybe (Bndr tv argf) = case argf of Required -> Just $ Bndr tv () Invisible _ -> Nothing -- | See Note [Invariant: Never expand type synonyms] tcSplitForAllTysInvisPreserveSynonyms :: Type -> ([InvisTVBinder], Type) tcSplitForAllTysInvisPreserveSynonyms ty = let (all_bndrs, body) = tcSplitSomeForAllTysPreserveSynonyms isInvisibleArgFlag ty inv_bndrs = mapMaybe mk_inv_bndr_maybe all_bndrs in assert ( inv_bndrs `equalLength` all_bndrs) (inv_bndrs, body) where mk_inv_bndr_maybe :: TyCoVarBinder -> Maybe InvisTVBinder mk_inv_bndr_maybe (Bndr tv argf) = case argf of Invisible s -> Just $ Bndr tv s Required -> Nothing -- | See Note [Invariant: Never expand type synonyms] -- | See Note [Invariant: Never expand type synonyms] tcSplitPhiTyPreserveSynonyms :: Type -> (ThetaType, Type) tcSplitPhiTyPreserveSynonyms ty0 = split ty0 [] where split ty ts = case tcSplitPredFunTyPreserveSynonyms_maybe ty of Just (pred_, ty') -> split ty' (pred_:ts) Nothing -> (reverse ts, ty) -- | See Note [Invariant: Never expand type synonyms] tcSplitPredFunTyPreserveSynonyms_maybe :: Type -> Maybe (PredType, Type) tcSplitPredFunTyPreserveSynonyms_maybe (FunTy InvisArg _ arg res) = Just (arg, res) tcSplitPredFunTyPreserveSynonyms_maybe _ = Nothing