getFunTy_maybe, getFunTyExpandingDicts_maybe,
mkTyConTy, getTyCon_maybe, applyTyCon,
mkSynTy,
- mkForAllTy, mkForAllTys, getForAllTy_maybe, getForAllTyExpandingDicts_maybe, splitForAllTy,
+ mkForAllTy, mkForAllTys, getForAllTy_maybe, getForAllTyExpandingDicts_maybe, splitForAllTy, splitForAllTyExpandingDicts,
mkForAllUsageTy, getForAllUsageTy,
applyTy,
#ifdef DEBUG
) where
IMP_Ubiq()
---IMPORT_DELOOPER(IdLoop) -- for paranoia checking
+#if defined(__GLASGOW_HASKELL__) && __GLASGOW_HASKELL__ <= 201
+IMPORT_DELOOPER(IdLoop) -- for paranoia checking
IMPORT_DELOOPER(TyLoop)
--IMPORT_DELOOPER(PrelLoop) -- for paranoia checking
+#else
+import {-# SOURCE #-} Id ( Id, dataConArgTys )
+import {-# SOURCE #-} TysPrim ( voidTy )
+import {-# SOURCE #-} TysWiredIn ( tupleTyCon )
+#endif
-- friends:
-import Class ( classSig, classOpLocalType, GenClass{-instances-} )
+import Class ( classSig, classOpLocalType, GenClass{-instances-}, SYN_IE(Class) )
import Kind ( mkBoxedTypeKind, resultKind, notArrowKind, Kind )
import TyCon ( mkFunTyCon, isFunTyCon, isEnumerationTyCon, isTupleTyCon, maybeTyConSingleCon,
- isPrimTyCon, isDataTyCon, isSynTyCon, maybeNewTyCon, isNewTyCon,
+ isPrimTyCon, isAlgTyCon, isDataTyCon, isSynTyCon, maybeNewTyCon, isNewTyCon,
tyConKind, tyConDataCons, getSynTyConDefn, TyCon )
import TyVar ( tyVarKind, GenTyVar{-instances-}, SYN_IE(GenTyVarSet),
emptyTyVarSet, unionTyVarSets, minusTyVarSet,
import Maybes ( maybeToBool, assocMaybe )
import PrimRep ( PrimRep(..) )
import Unique -- quite a few *Keys
+import UniqFM ( Uniquable(..) )
import Util ( thenCmp, zipEqual, assoc,
panic, panic#, assertPanic, pprPanic,
Ord3(..){-instances-}
-- PprStyle
--import {-mumble-}
-- PprType --(pprType )
---import {-mumble-}
--- UniqFM (ufmToList )
---import {-mumble-}
--- Outputable
--import PprEnv
\end{code}
\end{code}
+Notes on type synonyms
+~~~~~~~~~~~~~~~~~~~~~~
+The various "split" functions (splitFunTy, splitRhoTy, splitForAllTy) try
+to return type synonyms whereever possible. Thus
+
+ type Foo a = a -> a
+
+we want
+ splitFunTys (a -> Foo a) = ([a], Foo a)
+not ([a], a -> a)
+
+The reason is that we then get better (shorter) type signatures in
+interfaces. Notably this plays a role in tcTySigs in TcBinds.lhs.
+
+
Expand abbreviations
~~~~~~~~~~~~~~~~~~~~
Removes just the top level of any abbreviations.
-- ToDo: NUKE when we do dicts via newtype
getFunTy_maybe :: GenType t u -> Maybe (GenType t u, GenType t u)
-getFunTy_maybe (FunTy arg result _) = Just (arg,result)
-getFunTy_maybe (AppTy (AppTy (TyConTy tycon _) arg) res)
+getFunTy_maybe t
+ = go t t
+ where
+ -- See notes on type synonyms above
+ go syn_t (FunTy arg result _) = Just (arg,result)
+ go syn_t (AppTy (AppTy (TyConTy tycon _) arg) res)
| isFunTyCon tycon = Just (arg, res)
-getFunTy_maybe (SynTy _ _ t) = getFunTy_maybe t
-getFunTy_maybe other = Nothing
+ go syn_t (SynTy _ _ t) = go syn_t t
+ go syn_t other = Nothing
getFunTyExpandingDicts_maybe :: Bool -- True <=> peek inside newtype applicatons
-> Type
getFunTyExpandingDicts_maybe True (ForAllTy _ ty) = getFunTyExpandingDicts_maybe True ty
-- Ignore for-alls when peeking. See note with defn of getFunTyExpandingDictsAndPeeking
+
+{- This is a truly disgusting bit of code.
+ It's used by the code generator to look at the rep of a newtype.
+ The code gen will have thrown away coercions involving that newtype, so
+ this is the other side of the coin.
+ Gruesome in the extreme.
+-}
+
getFunTyExpandingDicts_maybe peek other
| not peek = Nothing -- that was easy
| otherwise
= case (maybeAppTyCon other) of
- Nothing -> Nothing
Just (tc, arg_tys)
- | not (isNewTyCon tc) -> Nothing
- | otherwise ->
- let
- [newtype_con] = tyConDataCons tc -- there must be exactly one...
- [inside_ty] = dataConArgTys newtype_con arg_tys
- in
- getFunTyExpandingDicts_maybe peek inside_ty
+ | isNewTyCon tc && not (null data_cons)
+ -> getFunTyExpandingDicts_maybe peek inside_ty
+ where
+ data_cons = tyConDataCons tc
+ [the_con] = data_cons
+ [inside_ty] = dataConArgTys the_con arg_tys
+
+ other -> Nothing
+
splitFunTy :: GenType t u -> ([GenType t u], GenType t u)
splitFunTyExpandingDicts :: Type -> ([Type], Type)
splitFunTyExpandingDictsAndPeeking t = split_fun_ty (getFunTyExpandingDicts_maybe True) t
-- This "peeking" stuff is used only by the code generator.
-- It's interested in the representation type of things, ignoring:
- -- newtype
+ -- newtype Why??? Nuked SLPJ May 97. We may not know the
+ -- rep of an abstractly imported newtype
-- foralls
-- expanding dictionary reps
-- synonyms, of course
splitRhoTy :: GenType t u -> ([(Class,GenType t u)], GenType t u)
splitRhoTy t =
- go t []
+ go t t []
where
- go (FunTy (DictTy c t _) r _) ts = go r ((c,t):ts)
- go (AppTy (AppTy (TyConTy tycon _) (DictTy c t _)) r) ts
+ -- See notes on type synonyms above
+ go syn_t (FunTy (DictTy c t _) r _) ts = go r r ((c,t):ts)
+ go syn_t (AppTy (AppTy (TyConTy tycon _) (DictTy c t _)) r) ts
| isFunTyCon tycon
- = go r ((c,t):ts)
- go (SynTy _ _ t) ts = go t ts
- go t ts = (reverse ts, t)
+ = go r r ((c,t):ts)
+ go syn_t (SynTy _ _ t) ts = go syn_t t ts
+ go syn_t t ts = (reverse ts, syn_t)
mkTheta :: [Type] -> ThetaType
getForAllTyExpandingDicts_maybe ty@(DictTy _ _ _) = getForAllTyExpandingDicts_maybe (expandTy ty)
getForAllTyExpandingDicts_maybe _ = Nothing
-splitForAllTy :: GenType t u-> ([t], GenType t u)
-splitForAllTy t = go t []
+splitForAllTy :: GenType t u -> ([t], GenType t u)
+splitForAllTy t = go t t []
where
- go (ForAllTy tv t) tvs = go t (tv:tvs)
- go (SynTy _ _ t) tvs = go t tvs
- go t tvs = (reverse tvs, t)
+ -- See notes on type synonyms above
+ go syn_t (ForAllTy tv t) tvs = go t t (tv:tvs)
+ go syn_t (SynTy _ _ t) tvs = go syn_t t tvs
+ go syn_t t tvs = (reverse tvs, syn_t)
+
+splitForAllTyExpandingDicts :: Type -> ([TyVar], Type)
+splitForAllTyExpandingDicts ty
+ = go [] ty
+ where
+ go tvs ty = case getForAllTyExpandingDicts_maybe ty of
+ Just (tv, ty') -> go (tv:tvs) ty'
+ Nothing -> (reverse tvs, ty)
\end{code}
\begin{code}
Applied data tycons (give back constrs)
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+Nota Bene: all these functions suceed for @newtype@ applications too!
+
\begin{code}
maybeAppDataTyCon
:: GenType (GenTyVar any) uvar
(app_ty, arg_tys) = splitAppTys expanded_ty
in
case (getTyCon_maybe app_ty) of
- Just tycon | --pprTrace "maybe_app:" (ppCat [ppr PprDebug (isDataTyCon tycon), ppr PprDebug (notArrowKind (typeKind expanded_ty))]) $
- isDataTyCon tycon &&
+ Just tycon | isAlgTyCon tycon && -- NB "Alg"; succeeds for newtype too
notArrowKind (typeKind expanded_ty)
-- Must be saturated for ty to be a data type
-> Just (tycon, arg_tys, tyConDataCons tycon)
maybeBoxedPrimType :: Type -> Maybe (Id, Type)
maybeBoxedPrimType ty
- = case (maybeAppDataTyCon ty) of -- Data type,
- Just (tycon, tys_applied, [data_con]) -- with exactly one constructor
+ = case (maybeAppDataTyCon ty) of -- Data type,
+ Just (tycon, tys_applied, [data_con]) | isDataTyCon tycon -- with exactly one constructor
-> case (dataConArgTys data_con tys_applied) of
[data_con_arg_ty] -- Applied to exactly one type,
| isPrimType data_con_arg_ty -- which is primitive
else
\x->x) ForAllTy (deflt_forall_tv tv) (go ty)
+instantiateTy [] ty = ty
+
instantiateTy tenv ty
= instant_help ty lookup_tv deflt_tv choose_tycon
if_usage if_forall bound_forall_tv_BAD deflt_forall_tv
projects / ghc-hetmet.git / blobdiff