tcSplitFunTy_maybe, tcSplitFunTys, tcFunArgTy, tcFunResultTy, tcSplitFunTysN,
tcSplitTyConApp, tcSplitTyConApp_maybe, tcTyConAppTyCon, tcTyConAppArgs,
tcSplitAppTy_maybe, tcSplitAppTy, tcSplitAppTys, repSplitAppTy_maybe,
- tcValidInstHeadTy, tcGetTyVar_maybe, tcGetTyVar,
+ tcInstHeadTyNotSynonym, tcInstHeadTyAppAllTyVars,
+ tcGetTyVar_maybe, tcGetTyVar,
tcSplitSigmaTy, tcMultiSplitSigmaTy,
---------------------------------
import Unify
import VarSet
import Type
+import Coercion
import TyCon
-- others:
-- or nothing if we don't have anything useful to say
pprSkolTvBinding tv
= ASSERT ( isTcTyVar tv )
- ppr_details (tcTyVarDetails tv)
+ quotes (ppr tv) <+> ppr_details (tcTyVarDetails tv)
where
- ppr_details (MetaTv TauTv _) = quotes (ppr tv) <+> ptext SLIT("is a meta type variable")
- ppr_details (MetaTv BoxTv _) = quotes (ppr tv) <+> ptext SLIT("is a boxy type variable")
+ ppr_details (MetaTv TauTv _) = ptext SLIT("is a meta type variable")
+ ppr_details (MetaTv BoxTv _) = ptext SLIT("is a boxy type variable")
ppr_details (MetaTv (SigTv info) _) = ppr_skol info
ppr_details (SkolemTv info) = ppr_skol info
- ppr_skol UnkSkol = empty -- Unhelpful; omit
- ppr_skol RuntimeUnkSkol = quotes (ppr tv) <+> ptext SLIT("is an unknown runtime type")
- ppr_skol info = quotes (ppr tv) <+> ptext SLIT("is bound by")
- <+> sep [pprSkolInfo info, nest 2 (ptext SLIT("at") <+> ppr (getSrcLoc tv))]
+ ppr_skol UnkSkol = empty -- Unhelpful; omit
+ ppr_skol RuntimeUnkSkol = ptext SLIT("is an unknown runtime type")
+ ppr_skol info = sep [ptext SLIT("is a rigid type variable bound by"),
+ sep [pprSkolInfo info,
+ nest 2 (ptext SLIT("at") <+> ppr (getSrcLoc tv))]]
pprSkolInfo :: SkolemInfo -> SDoc
pprSkolInfo (SigSkol ctxt) = pprUserTypeCtxt ctxt
(args,res') = tcSplitFunTys res
tcSplitFunTy_maybe :: Type -> Maybe (Type, Type)
-tcSplitFunTy_maybe ty | Just ty' <- tcView ty = tcSplitFunTy_maybe ty'
-tcSplitFunTy_maybe (FunTy arg res) = Just (arg, res)
-tcSplitFunTy_maybe other = Nothing
+tcSplitFunTy_maybe ty | Just ty' <- tcView ty = tcSplitFunTy_maybe ty'
+tcSplitFunTy_maybe (FunTy arg res) | not (isPredTy arg) = Just (arg, res)
+tcSplitFunTy_maybe other = Nothing
+ -- Note the (not (isPredTy arg)) guard
+ -- Consider (?x::Int) => Bool
+ -- We don't want to treat this as a function type!
+ -- A concrete example is test tc230:
+ -- f :: () -> (?p :: ()) => () -> ()
+ --
+ -- g = f () ()
tcSplitFunTysN
:: TcRhoType
Just (ClassP clas tys) -> (clas, tys)
other -> panic "tcSplitDFunHead"
-tcValidInstHeadTy :: Type -> Bool
+tcInstHeadTyNotSynonym :: Type -> Bool
-- Used in Haskell-98 mode, for the argument types of an instance head
-- These must not be type synonyms, but everywhere else type synonyms
-- are transparent, so we need a special function here
-tcValidInstHeadTy ty
+tcInstHeadTyNotSynonym ty
= case ty of
- NoteTy _ ty -> tcValidInstHeadTy ty
- TyConApp tc tys -> not (isSynTyCon tc) && ok tys
+ NoteTy _ ty -> tcInstHeadTyNotSynonym ty
+ TyConApp tc tys -> not (isSynTyCon tc)
+ _ -> True
+
+tcInstHeadTyAppAllTyVars :: Type -> Bool
+-- Used in Haskell-98 mode, for the argument types of an instance head
+-- These must be a constructor applied to type variable arguments
+tcInstHeadTyAppAllTyVars ty
+ = case ty of
+ NoteTy _ ty -> tcInstHeadTyAppAllTyVars ty
+ TyConApp _ tys -> ok tys
FunTy arg res -> ok [arg, res]
other -> False
where
predTyUnique :: PredType -> Unique
predTyUnique (IParam n _) = getUnique (ipNameName n)
predTyUnique (ClassP clas tys) = getUnique clas
+predTyUnique (EqPred a b) = pprPanic "predTyUnique" (ppr (EqPred a b))
\end{code}
go (AppTy fun arg) = go fun `unionVarSet` go arg
go (ForAllTy tyvar ty) = delVarSet (go ty) tyvar
`unionVarSet` go_tv tyvar
+ go (NoteTy _ _) = panic "exactTyVarsOfType" -- Handled by tcView
go_pred (IParam _ ty) = go ty
go_pred (ClassP _ tys) = exactTyVarsOfTypes tys
being the )
\begin{code}
-tcSplitIOType_maybe :: Type -> Maybe (TyCon, Type)
--- (isIOType t) returns (Just (IO,t')) if t is of the form (IO t'), or
--- some newtype wrapping thereof
+tcSplitIOType_maybe :: Type -> Maybe (TyCon, Type, CoercionI)
+-- (isIOType t) returns Just (IO,t',co)
+-- if co : t ~ IO t'
-- returns Nothing otherwise
tcSplitIOType_maybe ty
- | Just (io_tycon, [io_res_ty]) <- tcSplitTyConApp_maybe ty,
+ = case tcSplitTyConApp_maybe ty of
-- This split absolutely has to be a tcSplit, because we must
-- see the IO type; and it's a newtype which is transparent to splitTyConApp.
- io_tycon `hasKey` ioTyConKey
- = Just (io_tycon, io_res_ty)
- | Just ty' <- coreView ty -- Look through non-recursive newtypes
- = tcSplitIOType_maybe ty'
+ Just (io_tycon, [io_res_ty])
+ | io_tycon `hasKey` ioTyConKey
+ -> Just (io_tycon, io_res_ty, IdCo)
- | otherwise
- = Nothing
+ Just (tc, tys)
+ | not (isRecursiveTyCon tc)
+ , Just (ty, co1) <- instNewTyCon_maybe tc tys
+ -- Newtypes that require a coercion are ok
+ -> case tcSplitIOType_maybe ty of
+ Nothing -> Nothing
+ Just (tc, ty', co2) -> Just (tc, ty', co1 `mkTransCoI` co2)
+
+ other -> Nothing
isFFITy :: Type -> Bool
-- True for any TyCon that can possibly be an arg or result of an FFI call
-- it no longer does so. May need to adjust isFFIDotNetTy
-- if we do want to look through newtypes.
-isFFIDotnetObjTy ty =
- let
+isFFIDotnetObjTy ty
+ = checkRepTyCon check_tc t_ty
+ where
(_, t_ty) = tcSplitForAllTys ty
- in
- case tcSplitTyConApp_maybe (repType t_ty) of
- Just (tc, [arg_ty]) | getName tc == objectTyConName -> True
- _ -> False
+ check_tc tc = getName tc == objectTyConName
toDNType :: Type -> DNType
toDNType ty
= isUnLiftedTyCon tc || boxedMarshalableTyCon tc || tc == unitTyCon
marshalableTyCon dflags tc
- = (dopt Opt_GlasgowExts dflags && isUnLiftedTyCon tc)
+ = (dopt Opt_UnliftedFFITypes dflags
+ && isUnLiftedTyCon tc
+ && case tyConPrimRep tc of -- Note [Marshalling VoidRep]
+ VoidRep -> False
+ other -> True)
|| boxedMarshalableTyCon tc
boxedMarshalableTyCon tc
, boolTyConKey
]
\end{code}
+
+Note [Marshalling VoidRep]
+~~~~~~~~~~~~~~~~~~~~~~~~~~
+We don't treat State# (whose PrimRep is VoidRep) as marshalable.
+In turn that means you can't write
+ foreign import foo :: Int -> State# RealWorld
+
+Reason: the back end falls over with panic "primRepHint:VoidRep";
+ and there is no compelling reason to permit it