X-Git-Url: http://git.megacz.com/?p=ghc-hetmet.git;a=blobdiff_plain;f=compiler%2FbasicTypes%2FDataCon.lhs;h=312ae943a8ca3c9987060f2fc4f1461142abeb1e;hp=5a67ffe77b6283ac4a1a64b50ea1a928cd11f5e7;hb=c8c2f6bb7d79a2a6aeaa3233363fdf0bbbfad205;hpb=66579ff945831c5fc9a17c58c722ff01f2268d76 diff --git a/compiler/basicTypes/DataCon.lhs b/compiler/basicTypes/DataCon.lhs index 5a67ffe..312ae94 100644 --- a/compiler/basicTypes/DataCon.lhs +++ b/compiler/basicTypes/DataCon.lhs @@ -15,9 +15,11 @@ module DataCon ( -- ** Type deconstruction dataConRepType, dataConSig, dataConFullSig, - dataConName, dataConIdentity, dataConTag, dataConTyCon, dataConUserType, + dataConName, dataConIdentity, dataConTag, dataConTyCon, + dataConOrigTyCon, dataConUserType, dataConUnivTyVars, dataConExTyVars, dataConAllTyVars, - dataConEqSpec, eqSpecPreds, dataConEqTheta, dataConDictTheta, dataConStupidTheta, + dataConEqSpec, eqSpecPreds, dataConTheta, + dataConStupidTheta, dataConInstArgTys, dataConOrigArgTys, dataConOrigResTy, dataConInstOrigArgTys, dataConRepArgTys, dataConFieldLabels, dataConFieldType, @@ -29,7 +31,7 @@ module DataCon ( -- ** Predicates on DataCons isNullarySrcDataCon, isNullaryRepDataCon, isTupleCon, isUnboxedTupleCon, - isVanillaDataCon, classDataCon, + isVanillaDataCon, classDataCon, dataConCannotMatch, -- * Splitting product types splitProductType_maybe, splitProductType, deepSplitProductType, @@ -39,6 +41,7 @@ module DataCon ( #include "HsVersions.h" import Type +import Unify import Coercion import TyCon import Class @@ -49,13 +52,12 @@ import Outputable import Unique import ListSetOps import Util -import Maybes import FastString import Module +import qualified Data.Data as Data import Data.Char import Data.Word -import Data.List ( partition ) \end{code} @@ -96,12 +98,12 @@ Note [Data Constructor Naming] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Each data constructor C has two, and possibly up to four, Names associated with it: - OccName Name space Name of - --------------------------------------------------------------------------- - * The "data con itself" C DataName DataCon - * The "worker data con" C VarName Id (the worker) - * The "wrapper data con" \$WC VarName Id (the wrapper) - * The "newtype coercion" :CoT TcClsName TyCon + OccName Name space Name of Notes + --------------------------------------------------------------------------- + The "data con itself" C DataName DataCon In dom( GlobalRdrEnv ) + The "worker data con" C VarName Id The worker + The "wrapper data con" $WC VarName Id The wrapper + The "newtype coercion" :CoT TcClsName TyCon EVERY data constructor (incl for newtypes) has the former two (the data con itself, and its worker. But only some data constructors have a @@ -164,7 +166,7 @@ Why might the wrapper have anything to do? Two reasons: \$wMkT :: a -> T [a] \$wMkT a x = MkT [a] a [a] x The third argument is a coerion - [a] :: [a]:=:[a] + [a] :: [a]~[a] INVARIANT: the dictionary constructor for a class never has a wrapper. @@ -246,16 +248,15 @@ data DataCon -- *** As represented internally -- data T a where - -- MkT :: forall a. forall x y. (a:=:(x,y),x~y,Ord x) => x -> y -> T a + -- MkT :: forall a. forall x y. (a~(x,y),x~y,Ord x) => x -> y -> T a -- -- The next six fields express the type of the constructor, in pieces -- e.g. -- -- dcUnivTyVars = [a] -- dcExTyVars = [x,y] - -- dcEqSpec = [a:=:(x,y)] - -- dcEqTheta = [x~y] - -- dcDictTheta = [Ord x] + -- dcEqSpec = [a~(x,y)] + -- dcOtherTheta = [x~y, Ord x] -- dcOrigArgTys = [a,List b] -- dcRepTyCon = T @@ -263,14 +264,15 @@ data DataCon -- Its type is of form -- forall a1..an . t1 -> ... tm -> T a1..an -- No existentials, no coercions, nothing. - -- That is: dcExTyVars = dcEqSpec = dcEqTheta = dcDictTheta = [] + -- That is: dcExTyVars = dcEqSpec = dcOtherTheta = [] -- NB 1: newtypes always have a vanilla data con -- NB 2: a vanilla constructor can still be declared in GADT-style -- syntax, provided its type looks like the above. -- The declaration format is held in the TyCon (algTcGadtSyntax) - dcUnivTyVars :: [TyVar], -- Universally-quantified type vars + dcUnivTyVars :: [TyVar], -- Universally-quantified type vars [a,b,c] -- INVARIANT: length matches arity of the dcRepTyCon + --- result type of (rep) data con is exactly (T a b c) dcExTyVars :: [TyVar], -- Existentially-quantified type vars -- In general, the dcUnivTyVars are NOT NECESSARILY THE SAME AS THE TYVARS @@ -286,9 +288,9 @@ data DataCon -- _as written by the programmer_ -- This field allows us to move conveniently between the two ways -- of representing a GADT constructor's type: - -- MkT :: forall a b. (a :=: [b]) => b -> T a + -- MkT :: forall a b. (a ~ [b]) => b -> T a -- MkT :: forall b. b -> T [b] - -- Each equality is of the form (a :=: ty), where 'a' is one of + -- Each equality is of the form (a ~ ty), where 'a' is one of -- the universally quantified type variables -- The next two fields give the type context of the data constructor @@ -297,8 +299,8 @@ data DataCon -- In GADT form, this is *exactly* what the programmer writes, even if -- the context constrains only universally quantified variables -- MkT :: forall a b. (a ~ b, Ord b) => a -> T a b - dcEqTheta :: ThetaType, -- The *equational* constraints - dcDictTheta :: ThetaType, -- The *type-class and implicit-param* constraints + dcOtherTheta :: ThetaType, -- The other constraints in the data con's type + -- other than those in the dcEqSpec dcStupidTheta :: ThetaType, -- The context of the data type declaration -- data Eq a => T a = ... @@ -317,14 +319,14 @@ data DataCon dcOrigArgTys :: [Type], -- Original argument types -- (before unboxing and flattening of strict fields) - dcOrigResTy :: Type, -- Original result type + dcOrigResTy :: Type, -- Original result type, as seen by the user -- NB: for a data instance, the original user result type may -- differ from the DataCon's representation TyCon. Example -- data instance T [a] where MkT :: a -> T [a] -- The OrigResTy is T [a], but the dcRepTyCon might be :T123 -- Now the strictness annotations and field labels of the constructor - dcStrictMarks :: [StrictnessMark], + dcStrictMarks :: [HsBang], -- Strictness annotations as decided by the compiler. -- Does *not* include the existential dictionaries -- length = dataConSourceArity dataCon @@ -335,18 +337,19 @@ data DataCon -- length = 0 (if not a record) or dataConSourceArity. -- Constructor representation - dcRepArgTys :: [Type], -- Final, representation argument types, - -- after unboxing and flattening, - -- and *including* existential dictionaries + dcRepArgTys :: [Type], -- Final, representation argument types, + -- after unboxing and flattening, + -- and *including* all existential evidence args - dcRepStrictness :: [StrictnessMark], -- One for each *representation* argument + dcRepStrictness :: [StrictnessMark], + -- One for each *representation* *value* argument -- See also Note [Data-con worker strictness] in MkId.lhs -- Result type of constructor is T t1..tn dcRepTyCon :: TyCon, -- Result tycon, T dcRepType :: Type, -- Type of the constructor - -- forall a x y. (a:=:(x,y), x~y, Ord x) => + -- forall a x y. (a~(x,y), x~y, Ord x) => -- x -> y -> T a -- (this is *not* of the constructor wrapper Id: -- see Note [Data con representation] below) @@ -355,7 +358,7 @@ data DataCon -- case (e :: T t) of -- MkT x y co1 co2 (d:Ord x) (v:r) (w:F s) -> ... -- It's convenient to apply the rep-type of MkT to 't', to get - -- forall x y. (t:=:(x,y), x~y, Ord x) => x -> y -> T t + -- forall x y. (t~(x,y), x~y, Ord x) => x -> y -> T t -- and use that to check the pattern. Mind you, this is really only -- used in CoreLint. @@ -452,6 +455,15 @@ instance Outputable DataCon where instance Show DataCon where showsPrec p con = showsPrecSDoc p (ppr con) + +instance Data.Typeable DataCon where + typeOf _ = Data.mkTyConApp (Data.mkTyCon "DataCon") [] + +instance Data.Data DataCon where + -- don't traverse? + toConstr _ = abstractConstr "DataCon" + gunfold _ _ = error "gunfold" + dataTypeOf _ = mkNoRepType "DataCon" \end{code} @@ -465,15 +477,18 @@ instance Show DataCon where -- | Build a new data constructor mkDataCon :: Name -> Bool -- ^ Is the constructor declared infix? - -> [StrictnessMark] -- ^ Strictness annotations written in the source file - -> [FieldLabel] -- ^ Field labels for the constructor, if it is a record, otherwise empty + -> [HsBang] -- ^ Strictness annotations written in the source file + -> [FieldLabel] -- ^ Field labels for the constructor, if it is a record, + -- otherwise empty -> [TyVar] -- ^ Universally quantified type variables -> [TyVar] -- ^ Existentially quantified type variables -> [(TyVar,Type)] -- ^ GADT equalities -> ThetaType -- ^ Theta-type occuring before the arguments proper - -> [Type] -- ^ Argument types - -> TyCon -- ^ Type constructor we are for - -> ThetaType -- ^ The "stupid theta", context of the data declaration e.g. @data Eq a => T a ...@ + -> [Type] -- ^ Original argument types + -> Type -- ^ Original result type + -> TyCon -- ^ Representation type constructor + -> ThetaType -- ^ The "stupid theta", context of the data declaration + -- e.g. @data Eq a => T a ...@ -> DataConIds -- ^ The Ids of the actual builder functions -> DataCon -- Can get the tag from the TyCon @@ -483,7 +498,7 @@ mkDataCon name declared_infix fields univ_tvs ex_tvs eq_spec theta - orig_arg_tys tycon + orig_arg_tys orig_res_ty rep_tycon stupid_theta ids -- Warning: mkDataCon is not a good place to check invariants. -- If the programmer writes the wrong result type in the decl, thus: @@ -503,10 +518,10 @@ mkDataCon name declared_infix dcVanilla = is_vanilla, dcInfix = declared_infix, dcUnivTyVars = univ_tvs, dcExTyVars = ex_tvs, dcEqSpec = eq_spec, + dcOtherTheta = theta, dcStupidTheta = stupid_theta, - dcEqTheta = eq_theta, dcDictTheta = dict_theta, dcOrigArgTys = orig_arg_tys, dcOrigResTy = orig_res_ty, - dcRepTyCon = tycon, + dcRepTyCon = rep_tycon, dcRepArgTys = rep_arg_tys, dcStrictMarks = arg_stricts, dcRepStrictness = rep_arg_stricts, @@ -520,41 +535,25 @@ mkDataCon name declared_infix -- The 'arg_stricts' passed to mkDataCon are simply those for the -- source-language arguments. We add extra ones for the -- dictionary arguments right here. - (eq_theta,dict_theta) = partition isEqPred theta - dict_tys = mkPredTys dict_theta - real_arg_tys = dict_tys ++ orig_arg_tys - real_stricts = map mk_dict_strict_mark dict_theta ++ arg_stricts - - -- Example - -- data instance T (b,c) where - -- TI :: forall e. e -> T (e,e) - -- - -- The representation tycon looks like this: - -- data :R7T b c where - -- TI :: forall b1 c1. (b1 ~ c1) => b1 -> :R7T b1 c1 - -- In this case orig_res_ty = T (e,e) - orig_res_ty = mkFamilyTyConApp tycon (substTyVars (mkTopTvSubst eq_spec) univ_tvs) + full_theta = eqSpecPreds eq_spec ++ theta + real_arg_tys = mkPredTys full_theta ++ orig_arg_tys + real_stricts = map mk_dict_strict_mark full_theta ++ arg_stricts -- Representation arguments and demands -- To do: eliminate duplication with MkId (rep_arg_stricts, rep_arg_tys) = computeRep real_stricts real_arg_tys - tag = assoc "mkDataCon" (tyConDataCons tycon `zip` [fIRST_TAG..]) con + tag = assoc "mkDataCon" (tyConDataCons rep_tycon `zip` [fIRST_TAG..]) con ty = mkForAllTys univ_tvs $ mkForAllTys ex_tvs $ - mkFunTys (mkPredTys (eqSpecPreds eq_spec)) $ - mkFunTys (mkPredTys eq_theta) $ - -- NB: the dict args are already in rep_arg_tys - -- because they might be flattened.. - -- but the equality predicates are not mkFunTys rep_arg_tys $ - mkTyConApp tycon (mkTyVarTys univ_tvs) + mkTyConApp rep_tycon (mkTyVarTys univ_tvs) eqSpecPreds :: [(TyVar,Type)] -> ThetaType eqSpecPreds spec = [ mkEqPred (mkTyVarTy tv, ty) | (tv,ty) <- spec ] -mk_dict_strict_mark :: PredType -> StrictnessMark -mk_dict_strict_mark pred | isStrictPred pred = MarkedStrict - | otherwise = NotMarkedStrict +mk_dict_strict_mark :: PredType -> HsBang +mk_dict_strict_mark pred | isStrictPred pred = HsStrict + | otherwise = HsNoBang \end{code} \begin{code} @@ -570,6 +569,14 @@ dataConTag = dcTag dataConTyCon :: DataCon -> TyCon dataConTyCon = dcRepTyCon +-- | The original type constructor used in the definition of this data +-- constructor. In case of a data family instance, that will be the family +-- type constructor. +dataConOrigTyCon :: DataCon -> TyCon +dataConOrigTyCon dc + | Just (tc, _) <- tyConFamInst_maybe (dcRepTyCon dc) = tc + | otherwise = dcRepTyCon dc + -- | The representation type of the data constructor, i.e. the sort -- type that will represent values of this type at runtime dataConRepType :: DataCon -> Type @@ -597,13 +604,10 @@ dataConAllTyVars (MkData { dcUnivTyVars = univ_tvs, dcExTyVars = ex_tvs }) dataConEqSpec :: DataCon -> [(TyVar,Type)] dataConEqSpec = dcEqSpec --- | The equational constraints on the data constructor type -dataConEqTheta :: DataCon -> ThetaType -dataConEqTheta = dcEqTheta - --- | The type class and implicit parameter contsraints on the data constructor type -dataConDictTheta :: DataCon -> ThetaType -dataConDictTheta = dcDictTheta +-- | The *full* constraints on the constructor type +dataConTheta :: DataCon -> ThetaType +dataConTheta (MkData { dcEqSpec = eq_spec, dcOtherTheta = theta }) + = eqSpecPreds eq_spec ++ theta -- | Get the Id of the 'DataCon' worker: a function that is the "actual" -- constructor and has no top level binding in the program. The type may @@ -642,18 +646,20 @@ dataConFieldLabels = dcFields -- | Extract the type for any given labelled field of the 'DataCon' dataConFieldType :: DataCon -> FieldLabel -> Type -dataConFieldType con label = expectJust "unexpected label" $ - lookup label (dcFields con `zip` dcOrigArgTys con) +dataConFieldType con label + = case lookup label (dcFields con `zip` dcOrigArgTys con) of + Just ty -> ty + Nothing -> pprPanic "dataConFieldType" (ppr con <+> ppr label) -- | The strictness markings decided on by the compiler. Does not include those for -- existential dictionaries. The list is in one-to-one correspondence with the arity of the 'DataCon' -dataConStrictMarks :: DataCon -> [StrictnessMark] +dataConStrictMarks :: DataCon -> [HsBang] dataConStrictMarks = dcStrictMarks --- | Strictness of /existential/ arguments only -dataConExStricts :: DataCon -> [StrictnessMark] +-- | Strictness of evidence arguments to the wrapper function +dataConExStricts :: DataCon -> [HsBang] -- Usually empty, so we don't bother to cache this -dataConExStricts dc = map mk_dict_strict_mark $ dcDictTheta dc +dataConExStricts dc = map mk_dict_strict_mark $ (dataConTheta dc) -- | Source-level arity of the data constructor dataConSourceArity :: DataCon -> Arity @@ -689,9 +695,10 @@ dataConRepStrictness dc = dcRepStrictness dc -- -- 4) The /original/ result type of the 'DataCon' dataConSig :: DataCon -> ([TyVar], ThetaType, [Type], Type) -dataConSig (MkData {dcUnivTyVars = univ_tvs, dcExTyVars = ex_tvs, dcEqSpec = eq_spec, - dcEqTheta = eq_theta, dcDictTheta = dict_theta, dcOrigArgTys = arg_tys, dcOrigResTy = res_ty}) - = (univ_tvs ++ ex_tvs, eqSpecPreds eq_spec ++ eq_theta ++ dict_theta, arg_tys, res_ty) +dataConSig (MkData {dcUnivTyVars = univ_tvs, dcExTyVars = ex_tvs, + dcEqSpec = eq_spec, dcOtherTheta = theta, + dcOrigArgTys = arg_tys, dcOrigResTy = res_ty}) + = (univ_tvs ++ ex_tvs, eqSpecPreds eq_spec ++ theta, arg_tys, res_ty) -- | The \"full signature\" of the 'DataCon' returns, in order: -- @@ -703,14 +710,16 @@ dataConSig (MkData {dcUnivTyVars = univ_tvs, dcExTyVars = ex_tvs, dcEqSpec = eq_ -- -- 4) The result of 'dataConDictTheta' -- --- 5) The original argument types to the 'DataCon' (i.e. before any change of the representation of the type) +-- 5) The original argument types to the 'DataCon' (i.e. before +-- any change of the representation of the type) -- -- 6) The original result type of the 'DataCon' dataConFullSig :: DataCon - -> ([TyVar], [TyVar], [(TyVar,Type)], ThetaType, ThetaType, [Type], Type) -dataConFullSig (MkData {dcUnivTyVars = univ_tvs, dcExTyVars = ex_tvs, dcEqSpec = eq_spec, - dcEqTheta = eq_theta, dcDictTheta = dict_theta, dcOrigArgTys = arg_tys, dcOrigResTy = res_ty}) - = (univ_tvs, ex_tvs, eq_spec, eq_theta, dict_theta, arg_tys, res_ty) + -> ([TyVar], [TyVar], [(TyVar,Type)], ThetaType, [Type], Type) +dataConFullSig (MkData {dcUnivTyVars = univ_tvs, dcExTyVars = ex_tvs, + dcEqSpec = eq_spec, dcOtherTheta = theta, + dcOrigArgTys = arg_tys, dcOrigResTy = res_ty}) + = (univ_tvs, ex_tvs, eq_spec, theta, arg_tys, res_ty) dataConOrigResTy :: DataCon -> Type dataConOrigResTy dc = dcOrigResTy dc @@ -729,17 +738,16 @@ dataConUserType :: DataCon -> Type -- -- rather than: -- --- > T :: forall a c. forall b. (c=[a]) => a -> b -> T c +-- > T :: forall a c. forall b. (c~[a]) => a -> b -> T c -- -- NB: If the constructor is part of a data instance, the result type -- mentions the family tycon, not the internal one. dataConUserType (MkData { dcUnivTyVars = univ_tvs, dcExTyVars = ex_tvs, dcEqSpec = eq_spec, - dcEqTheta = eq_theta, dcDictTheta = dict_theta, dcOrigArgTys = arg_tys, + dcOtherTheta = theta, dcOrigArgTys = arg_tys, dcOrigResTy = res_ty }) = mkForAllTys ((univ_tvs `minusList` map fst eq_spec) ++ ex_tvs) $ - mkFunTys (mkPredTys eq_theta) $ - mkFunTys (mkPredTys dict_theta) $ + mkFunTys (mkPredTys theta) $ mkFunTys arg_tys $ res_ty @@ -822,6 +830,25 @@ classDataCon clas = case tyConDataCons (classTyCon clas) of [] -> panic "classDataCon" \end{code} +\begin{code} +dataConCannotMatch :: [Type] -> DataCon -> Bool +-- Returns True iff the data con *definitely cannot* match a +-- scrutinee of type (T tys) +-- where T is the type constructor for the data con +-- NB: look at *all* equality constraints, not only those +-- in dataConEqSpec; see Trac #5168 +dataConCannotMatch tys con + | null theta = False -- Common + | all isTyVarTy tys = False -- Also common + | otherwise + = typesCantMatch [(Type.substTy subst ty1, Type.substTy subst ty2) + | EqPred ty1 ty2 <- theta ] + where + dc_tvs = dataConUnivTyVars con + theta = dataConTheta con + subst = zipTopTvSubst dc_tvs tys +\end{code} + %************************************************************************ %* * \subsection{Splitting products} @@ -894,7 +921,7 @@ deepSplitProductType str ty Nothing -> pprPanic (str ++ ": not a product") (pprType ty) -- | Compute the representation type strictness and type suitable for a 'DataCon' -computeRep :: [StrictnessMark] -- ^ Original argument strictness +computeRep :: [HsBang] -- ^ Original argument strictness -> [Type] -- ^ Original argument types -> ([StrictnessMark], -- Representation arg strictness [Type]) -- And type @@ -902,10 +929,11 @@ computeRep :: [StrictnessMark] -- ^ Original argument strictness computeRep stricts tys = unzip $ concat $ zipWithEqual "computeRep" unbox stricts tys where - unbox NotMarkedStrict ty = [(NotMarkedStrict, ty)] - unbox MarkedStrict ty = [(MarkedStrict, ty)] - unbox MarkedUnboxed ty = zipEqual "computeRep" (dataConRepStrictness arg_dc) arg_tys - where - (_tycon, _tycon_args, arg_dc, arg_tys) - = deepSplitProductType "unbox_strict_arg_ty" ty + unbox HsNoBang ty = [(NotMarkedStrict, ty)] + unbox HsStrict ty = [(MarkedStrict, ty)] + unbox HsUnpackFailed ty = [(MarkedStrict, ty)] + unbox HsUnpack ty = zipEqual "computeRep" (dataConRepStrictness arg_dc) arg_tys + where + (_tycon, _tycon_args, arg_dc, arg_tys) + = deepSplitProductType "unbox_strict_arg_ty" ty \end{code}