\begin{code}
module TyCon(
- TyCon, ArgVrcs,
+ TyCon, ArgVrcs, FieldLabel,
PrimRep(..),
tyConPrimRep,
AlgTyConRhs(..), visibleDataCons,
- isFunTyCon, isUnLiftedTyCon, isProductTyCon, isAbstractTyCon,
+ isFunTyCon, isUnLiftedTyCon, isProductTyCon,
isAlgTyCon, isDataTyCon, isSynTyCon, isNewTyCon, isPrimTyCon,
isEnumerationTyCon,
isTupleTyCon, isUnboxedTupleTyCon, isBoxedTupleTyCon, tupleTyConBoxity,
- isRecursiveTyCon, newTyConRep, newTyConRhs, isHiBootTyCon,
+ isRecursiveTyCon, newTyConRep, newTyConRhs,
+ isHiBootTyCon,
+
+ tcExpandTyCon_maybe, coreExpandTyCon_maybe,
+
+ makeTyConAbstract, isAbstractTyCon,
mkForeignTyCon, isForeignTyCon,
tyConArgVrcs,
algTyConRhs, tyConDataCons, tyConDataCons_maybe, tyConFamilySize,
tyConSelIds,
- tyConTheta,
+ tyConStupidTheta,
tyConArity,
isClassTyCon, tyConClass_maybe,
- getSynTyConDefn,
+ synTyConDefn, synTyConRhs,
tyConExtName, -- External name for foreign types
maybeTyConSingleCon,
-- Should just be Type(Type), but this fails due to bug present up to
-- and including 4.02 involving slurping of hi-boot files. Bug is now fixed.
-import {-# SOURCE #-} DataCon ( DataCon, isExistentialDataCon )
+import {-# SOURCE #-} DataCon ( DataCon, isVanillaDataCon )
import Var ( TyVar, Id )
tyConKind :: Kind,
tyConArity :: Arity,
- tyConTyVars :: [TyVar],
- argVrcs :: ArgVrcs,
- algTyConTheta :: [PredType],
+ tyConTyVars :: [TyVar], -- Scopes over (a) the [PredType] in AlgTyConRhs.DataTyCon
+ -- (b) the cached types in AlgTyConRhs.NewTyCon
+ -- But not over the data constructors
+ argVrcs :: ArgVrcs,
+
+ algTcSelIds :: [Id], -- Its record selectors (empty if none):
- selIds :: [Id], -- Its record selectors (if any)
+ algTcStupidTheta :: [PredType], -- The "stupid theta" for the data type
+ -- (always empty for GADTs)
- algRhs :: AlgTyConRhs, -- Data constructors in here
+ algTcRhs :: AlgTyConRhs, -- Data constructors in here
- algTyConRec :: RecFlag, -- Tells whether the data type is part of
+ algTcRec :: RecFlag, -- Tells whether the data type is part of
-- a mutually-recursive group or not
hasGenerics :: Bool, -- True <=> generic to/from functions are available
- -- (in the exports of the data type's source module)
+ -- (in the exports of the data type's source module)
- algTyConClass :: Maybe Class
+ algTcClass :: Maybe Class
-- Just cl if this tycon came from a class declaration
}
tyConArity :: Arity,
tyConTyVars :: [TyVar], -- Bound tyvars
- synTyConDefn :: Type, -- Right-hand side, mentioning these type vars.
+ synTcRhs :: Type, -- Right-hand side, mentioning these type vars.
-- Acts as a template for the expansion when
-- the tycon is applied to some types.
argVrcs :: ArgVrcs
}
+type FieldLabel = Name
+
type ArgVrcs = [(Bool,Bool)] -- Tyvar variance info: [(occPos,occNeg)]
-- [] means "no information, assume the worst"
-- Used when we export a data type abstractly into
-- an hi file
- | DataTyCon
- [DataCon] -- The constructors; can be empty if the user declares
+ | DataTyCon {
+ data_cons :: [DataCon],
+ -- The constructors; can be empty if the user declares
-- the type to have no constructors
- Bool -- Cached: True <=> an enumeration type
+ -- INVARIANT: Kept in order of increasing tag
+ -- (see the tag assignment in DataCon.mkDataCon)
+ is_enum :: Bool -- Cached: True <=> an enumeration type
+ } -- Includes data types with no constructors.
+
+ | NewTyCon {
+ data_con :: DataCon, -- The unique constructor; it has no existentials
- | NewTyCon -- Newtypes always have exactly one constructor
- DataCon -- The unique constructor; it has no existentials
- Type -- Cached: the argument type of the constructor
- -- = the representation type of the tycon
+ nt_rhs :: Type, -- Cached: the argument type of the constructor
+ -- = the representation type of the tycon
- Type -- Cached: the *ultimate* representation type
- -- By 'ultimate' I mean that the rep type is not itself
- -- a newtype or type synonym.
+ nt_etad_rhs :: ([TyVar], Type) ,
+ -- The same again, but this time eta-reduced
+ -- hence the [TyVar] which may be shorter than the declared
+ -- arity of the TyCon. See Note [Newtype eta]
+
+ nt_rep :: Type -- Cached: the *ultimate* representation type
+ -- By 'ultimate' I mean that the top-level constructor
+ -- of the rep type is not itself a newtype or type synonym.
-- The rep type isn't entirely simple:
-- for a recursive newtype we pick () as the rep type
-- newtype T = MkT T
- --
- -- The rep type has free type variables the tyConTyVars
+ --
+ -- This one does not need to be eta reduced; hence its
+ -- free type variables are conveniently tyConTyVars
-- Thus:
-- newtype T a = MkT [(a,Int)]
-- The rep type is [(a,Int)]
- -- NB: the rep type isn't necessarily the original RHS of the
- -- newtype decl, because the rep type looks through other
- -- newtypes.
+ -- NB: the rep type isn't necessarily the original RHS of the
+ -- newtype decl, because the rep type looks through other
+ } -- newtypes.
visibleDataCons :: AlgTyConRhs -> [DataCon]
-visibleDataCons AbstractTyCon = []
-visibleDataCons (DataTyCon cs _) = cs
-visibleDataCons (NewTyCon c _ _) = [c]
+visibleDataCons AbstractTyCon = []
+visibleDataCons (DataTyCon{ data_cons = cs }) = cs
+visibleDataCons (NewTyCon{ data_con = c }) = [c]
\end{code}
+Note [Newtype eta]
+~~~~~~~~~~~~~~~~~~
+Consider
+ newtype Parser m a = MkParser (Foogle m a)
+Are these two types equal (to Core)?
+ Monad (Parser m)
+ Monad (Foogle m)
+Well, yes. But to see that easily we eta-reduce the RHS type of
+Parser, in this case to ([], Froogle), so that even unsaturated applications
+of Parser will work right. This eta reduction is done when the type
+constructor is built, and cached in NewTyCon. The cached field is
+only used in coreExpandTyCon_maybe.
+
+Here's an example that I think showed up in practice
+Source code:
+ newtype T a = MkT [a]
+ newtype Foo m = MkFoo (forall a. m a -> Int)
+
+ w1 :: Foo []
+ w1 = ...
+
+ w2 :: Foo T
+ w2 = MkFoo (\(MkT x) -> case w1 of MkFoo f -> f x)
+
+After desugaring, and discading the data constructors for the newtypes,
+we get:
+ w2 :: Foo T
+ w2 = w1
+And now Lint complains unless Foo T == Foo [], and that requires T==[]
+
+
%************************************************************************
%* *
\subsection{PrimRep}
-- This is the making of a TyCon. Just the same as the old mkAlgTyCon,
-- but now you also have to pass in the generic information about the type
-- constructor - you can get hold of it easily (see Generics module)
-mkAlgTyCon name kind tyvars theta argvrcs rhs sels is_rec gen_info
+mkAlgTyCon name kind tyvars argvrcs stupid rhs sel_ids is_rec gen_info
= AlgTyCon {
- tyConName = name,
- tyConUnique = nameUnique name,
- tyConKind = kind,
- tyConArity = length tyvars,
- tyConTyVars = tyvars,
- argVrcs = argvrcs,
- algTyConTheta = theta,
- algRhs = rhs,
- selIds = sels,
- algTyConClass = Nothing,
- algTyConRec = is_rec,
- hasGenerics = gen_info
+ tyConName = name,
+ tyConUnique = nameUnique name,
+ tyConKind = kind,
+ tyConArity = length tyvars,
+ tyConTyVars = tyvars,
+ argVrcs = argvrcs,
+ algTcStupidTheta = stupid,
+ algTcRhs = rhs,
+ algTcSelIds = sel_ids,
+ algTcClass = Nothing,
+ algTcRec = is_rec,
+ hasGenerics = gen_info
}
mkClassTyCon name kind tyvars argvrcs rhs clas is_rec
= AlgTyCon {
- tyConName = name,
- tyConUnique = nameUnique name,
- tyConKind = kind,
- tyConArity = length tyvars,
- tyConTyVars = tyvars,
- argVrcs = argvrcs,
- algTyConTheta = [],
- algRhs = rhs,
- selIds = [],
- algTyConClass = Just clas,
- algTyConRec = is_rec,
- hasGenerics = False
+ tyConName = name,
+ tyConUnique = nameUnique name,
+ tyConKind = kind,
+ tyConArity = length tyvars,
+ tyConTyVars = tyvars,
+ argVrcs = argvrcs,
+ algTcStupidTheta = [],
+ algTcRhs = rhs,
+ algTcSelIds = [],
+ algTcClass = Just clas,
+ algTcRec = is_rec,
+ hasGenerics = False
}
tyConKind = kind,
tyConArity = length tyvars,
tyConTyVars = tyvars,
- synTyConDefn = rhs,
+ synTcRhs = rhs,
argVrcs = argvrcs
}
\end{code}
isFunTyCon _ = False
isAbstractTyCon :: TyCon -> Bool
-isAbstractTyCon (AlgTyCon { algRhs = AbstractTyCon }) = True
+isAbstractTyCon (AlgTyCon { algTcRhs = AbstractTyCon }) = True
isAbstractTyCon _ = False
+makeTyConAbstract :: TyCon -> TyCon
+makeTyConAbstract tc@(AlgTyCon {}) = tc { algTcRhs = AbstractTyCon }
+makeTyConAbstract tc = pprPanic "makeTyConAbstract" (ppr tc)
+
isPrimTyCon :: TyCon -> Bool
isPrimTyCon (PrimTyCon {}) = True
isPrimTyCon _ = False
isAlgTyCon (TupleTyCon {}) = True
isAlgTyCon other = False
-algTyConRhs :: TyCon -> AlgTyConRhs
-algTyConRhs (AlgTyCon {algRhs = rhs}) = rhs
-algTyConRhs (TupleTyCon {dataCon = dc}) = DataTyCon [dc] False
-
isDataTyCon :: TyCon -> Bool
-- isDataTyCon returns True for data types that are represented by
-- heap-allocated constructors.
-- True for all @data@ types
-- False for newtypes
-- unboxed tuples
-isDataTyCon (AlgTyCon {algRhs = rhs})
+isDataTyCon tc@(AlgTyCon {algTcRhs = rhs})
= case rhs of
- DataTyCon _ _ -> True
- NewTyCon _ _ _ -> False
- AbstractTyCon -> panic "isDataTyCon"
+ DataTyCon {} -> True
+ NewTyCon {} -> False
+ AbstractTyCon -> pprPanic "isDataTyCon" (ppr tc)
isDataTyCon (TupleTyCon {tyConBoxed = boxity}) = isBoxed boxity
isDataTyCon other = False
isNewTyCon :: TyCon -> Bool
-isNewTyCon (AlgTyCon {algRhs = NewTyCon _ _ _}) = True
-isNewTyCon other = False
+isNewTyCon (AlgTyCon {algTcRhs = NewTyCon {}}) = True
+isNewTyCon other = False
isProductTyCon :: TyCon -> Bool
-- A "product" tycon
-- may be DataType or NewType,
-- may be unboxed or not,
-- may be recursive or not
-isProductTyCon tc@(AlgTyCon {}) = case algRhs tc of
- DataTyCon [data_con] _ -> not (isExistentialDataCon data_con)
- NewTyCon _ _ _ -> True
- other -> False
+isProductTyCon tc@(AlgTyCon {}) = case algTcRhs tc of
+ DataTyCon{ data_cons = [data_con] }
+ -> isVanillaDataCon data_con
+ NewTyCon {} -> True
+ other -> False
isProductTyCon (TupleTyCon {}) = True
isProductTyCon other = False
isSynTyCon _ = False
isEnumerationTyCon :: TyCon -> Bool
-isEnumerationTyCon (AlgTyCon {algRhs = DataTyCon _ is_enum}) = is_enum
-isEnumerationTyCon other = False
+isEnumerationTyCon (AlgTyCon {algTcRhs = DataTyCon { is_enum = res }}) = res
+isEnumerationTyCon other = False
isTupleTyCon :: TyCon -> Bool
-- The unit tycon didn't used to be classed as a tuple tycon
-- but I thought that was silly so I've undone it
-- If it can't be for some reason, it should be a AlgTyCon
+--
+-- NB: when compiling Data.Tuple, the tycons won't reply True to
+-- isTupleTyCon, becuase they are built as AlgTyCons. However they
+-- get spat into the interface file as tuple tycons, so I don't think
+-- it matters.
isTupleTyCon (TupleTyCon {}) = True
isTupleTyCon other = False
tupleTyConBoxity tc = tyConBoxed tc
isRecursiveTyCon :: TyCon -> Bool
-isRecursiveTyCon (AlgTyCon {algTyConRec = Recursive}) = True
+isRecursiveTyCon (AlgTyCon {algTcRec = Recursive}) = True
isRecursiveTyCon other = False
isHiBootTyCon :: TyCon -> Bool
-- Used for knot-tying in hi-boot files
-isHiBootTyCon (AlgTyCon {algRhs = AbstractTyCon}) = True
-isHiBootTyCon other = False
+isHiBootTyCon (AlgTyCon {algTcRhs = AbstractTyCon}) = True
+isHiBootTyCon other = False
isForeignTyCon :: TyCon -> Bool
-- isForeignTyCon identifies foreign-imported type constructors
isForeignTyCon other = False
\end{code}
+
+-----------------------------------------------
+-- Expand type-constructor applications
+-----------------------------------------------
+
+\begin{code}
+tcExpandTyCon_maybe, coreExpandTyCon_maybe
+ :: TyCon
+ -> [Type] -- Args to tycon
+ -> Maybe ([(TyVar,Type)], -- Substitution
+ Type, -- Body type (not yet substituted)
+ [Type]) -- Leftover args
+
+-- For the *typechecker* view, we expand synonyms only
+tcExpandTyCon_maybe (SynTyCon {tyConTyVars = tvs, synTcRhs = rhs }) tys
+ = expand tvs rhs tys
+tcExpandTyCon_maybe other_tycon tys = Nothing
+
+---------------
+-- For the *Core* view, we expand synonyms *and* non-recursive newtypes
+coreExpandTyCon_maybe (AlgTyCon {algTcRec = NonRecursive, -- Not recursive
+ algTcRhs = NewTyCon { nt_etad_rhs = etad_rhs }}) tys
+ = case etad_rhs of -- Don't do this in the pattern match, lest we accidentally
+ -- match the etad_rhs of a *recursive* newtype
+ (tvs,rhs) -> expand tvs rhs tys
+
+coreExpandTyCon_maybe tycon tys = tcExpandTyCon_maybe tycon tys
+
+----------------
+expand :: [TyVar] -> Type -- Template
+ -> [Type] -- Args
+ -> Maybe ([(TyVar,Type)], Type, [Type]) -- Expansion
+expand tvs rhs tys
+ = case n_tvs `compare` length tys of
+ LT -> Just (tvs `zip` tys, rhs, drop n_tvs tys)
+ EQ -> Just (tvs `zip` tys, rhs, [])
+ GT -> Nothing
+ where
+ n_tvs = length tvs
+\end{code}
+
\begin{code}
tyConHasGenerics :: TyCon -> Bool
tyConHasGenerics (AlgTyCon {hasGenerics = hg}) = hg
tyConDataCons tycon = tyConDataCons_maybe tycon `orElse` []
tyConDataCons_maybe :: TyCon -> Maybe [DataCon]
-tyConDataCons_maybe (AlgTyCon {algRhs = DataTyCon cons _}) = Just cons
-tyConDataCons_maybe (AlgTyCon {algRhs = NewTyCon con _ _}) = Just [con]
-tyConDataCons_maybe (TupleTyCon {dataCon = con}) = Just [con]
-tyConDataCons_maybe other = Nothing
+tyConDataCons_maybe (AlgTyCon {algTcRhs = DataTyCon { data_cons = cons }}) = Just cons
+tyConDataCons_maybe (AlgTyCon {algTcRhs = NewTyCon { data_con = con }}) = Just [con]
+tyConDataCons_maybe (TupleTyCon {dataCon = con}) = Just [con]
+tyConDataCons_maybe other = Nothing
tyConFamilySize :: TyCon -> Int
-tyConFamilySize (AlgTyCon {algRhs = DataTyCon cons _}) = length cons
-tyConFamilySize (AlgTyCon {algRhs = NewTyCon _ _ _}) = 1
-tyConFamilySize (TupleTyCon {}) = 1
+tyConFamilySize (AlgTyCon {algTcRhs = DataTyCon { data_cons = cons }}) = length cons
+tyConFamilySize (AlgTyCon {algTcRhs = NewTyCon {}}) = 1
+tyConFamilySize (TupleTyCon {}) = 1
#ifdef DEBUG
tyConFamilySize other = pprPanic "tyConFamilySize:" (ppr other)
#endif
tyConSelIds :: TyCon -> [Id]
-tyConSelIds (AlgTyCon {selIds = sels}) = sels
-tyConSelIds other_tycon = []
+tyConSelIds (AlgTyCon {algTcSelIds = fs}) = fs
+tyConSelIds other_tycon = []
+
+algTyConRhs :: TyCon -> AlgTyConRhs
+algTyConRhs (AlgTyCon {algTcRhs = rhs}) = rhs
+algTyConRhs (TupleTyCon {dataCon = con}) = DataTyCon { data_cons = [con], is_enum = False }
+algTyConRhs other = pprPanic "algTyConRhs" (ppr other)
\end{code}
\begin{code}
-newTyConRep :: TyCon -> ([TyVar], Type)
-newTyConRep (AlgTyCon {tyConTyVars = tvs, algRhs = NewTyCon _ _ rep}) = (tvs, rep)
-
newTyConRhs :: TyCon -> ([TyVar], Type)
-newTyConRhs (AlgTyCon {tyConTyVars = tvs, algRhs = NewTyCon _ rhs _}) = (tvs, rhs)
-\end{code}
+newTyConRhs (AlgTyCon {tyConTyVars = tvs, algTcRhs = NewTyCon { nt_rhs = rhs }}) = (tvs, rhs)
+newTyConRhs tycon = pprPanic "newTyConRhs" (ppr tycon)
+
+newTyConRep :: TyCon -> ([TyVar], Type)
+newTyConRep (AlgTyCon {tyConTyVars = tvs, algTcRhs = NewTyCon { nt_rep = rep }}) = (tvs, rep)
+newTyConRep tycon = pprPanic "newTyConRep" (ppr tycon)
-\begin{code}
tyConPrimRep :: TyCon -> PrimRep
tyConPrimRep (PrimTyCon {primTyConRep = rep}) = rep
tyConPrimRep tc = ASSERT(not (isUnboxedTupleTyCon tc)) PtrRep
\end{code}
\begin{code}
-tyConTheta :: TyCon -> [PredType]
-tyConTheta (AlgTyCon {algTyConTheta = theta}) = theta
-tyConTheta (TupleTyCon {}) = []
--- shouldn't ask about anything else
+tyConStupidTheta :: TyCon -> [PredType]
+tyConStupidTheta (AlgTyCon {algTcStupidTheta = stupid}) = stupid
+tyConStupidTheta (TupleTyCon {}) = []
+tyConStupidTheta tycon = pprPanic "tyConStupidTheta" (ppr tycon)
\end{code}
@tyConArgVrcs_maybe@ gives a list of (occPos,occNeg) flags, one for
\end{code}
\begin{code}
-getSynTyConDefn :: TyCon -> ([TyVar], Type)
-getSynTyConDefn (SynTyCon {tyConTyVars = tyvars, synTyConDefn = ty}) = (tyvars,ty)
+synTyConDefn :: TyCon -> ([TyVar], Type)
+synTyConDefn (SynTyCon {tyConTyVars = tyvars, synTcRhs = ty}) = (tyvars,ty)
+synTyConDefn tycon = pprPanic "getSynTyConDefn" (ppr tycon)
+
+synTyConRhs :: TyCon -> Type
+synTyConRhs tc = synTcRhs tc
\end{code}
\begin{code}
maybeTyConSingleCon :: TyCon -> Maybe DataCon
-maybeTyConSingleCon (AlgTyCon {algRhs = DataTyCon [c] _}) = Just c
-maybeTyConSingleCon (AlgTyCon {algRhs = NewTyCon c _ _}) = Just c
-maybeTyConSingleCon (AlgTyCon {}) = Nothing
-maybeTyConSingleCon (TupleTyCon {dataCon = con}) = Just con
-maybeTyConSingleCon (PrimTyCon {}) = Nothing
-maybeTyConSingleCon (FunTyCon {}) = Nothing -- case at funty
+maybeTyConSingleCon (AlgTyCon {algTcRhs = DataTyCon {data_cons = [c] }}) = Just c
+maybeTyConSingleCon (AlgTyCon {algTcRhs = NewTyCon { data_con = c }}) = Just c
+maybeTyConSingleCon (AlgTyCon {}) = Nothing
+maybeTyConSingleCon (TupleTyCon {dataCon = con}) = Just con
+maybeTyConSingleCon (PrimTyCon {}) = Nothing
+maybeTyConSingleCon (FunTyCon {}) = Nothing -- case at funty
maybeTyConSingleCon tc = pprPanic "maybeTyConSingleCon: unexpected tycon " $ ppr tc
\end{code}
\begin{code}
isClassTyCon :: TyCon -> Bool
-isClassTyCon (AlgTyCon {algTyConClass = Just _}) = True
+isClassTyCon (AlgTyCon {algTcClass = Just _}) = True
isClassTyCon other_tycon = False
tyConClass_maybe :: TyCon -> Maybe Class
-tyConClass_maybe (AlgTyCon {algTyConClass = maybe_clas}) = maybe_clas
+tyConClass_maybe (AlgTyCon {algTcClass = maybe_clas}) = maybe_clas
tyConClass_maybe ther_tycon = Nothing
\end{code}
projects / ghc-hetmet.git / blobdiff