\begin{code}
module TcType (
- TcTyVar, TcBox,
+ TcTyVar,
TcTyVarSet,
- newTcTyVar,
- newTyVarTy, -- Kind -> NF_TcM s (TcType s)
- newTyVarTys, -- Int -> Kind -> NF_TcM s [TcType s]
+ newTyVar,
+ newTyVarTy, -- Kind -> NF_TcM s TcType
+ newTyVarTys, -- Int -> Kind -> NF_TcM s [TcType]
+
+ newTyVarTy_OpenKind, -- NF_TcM s TcType
+ newOpenTypeKind, -- NF_TcM s TcKind
-----------------------------------------
- TcType, TcMaybe(..),
- TcTauType, TcThetaType, TcRhoType,
+ TcType, TcTauType, TcThetaType, TcRhoType,
-- Find the type to which a type variable is bound
- tcWriteTyVar, -- :: TcTyVar s -> TcType s -> NF_TcM (TcType s)
- tcReadTyVar, -- :: TcTyVar s -> NF_TcM (TcMaybe s)
+ tcPutTyVar, -- :: TcTyVar -> TcType -> NF_TcM TcType
+ tcGetTyVar, -- :: TcTyVar -> NF_TcM (Maybe TcType) does shorting out
tcSplitRhoTy,
typeToTcType,
+ tcTypeKind, -- :: TcType -> NF_TcM s TcKind
--------------------------------
TcKind,
newKindVar, newKindVars,
-- friends:
-import PprType ()
-import Type ( Type, Kind, ThetaType, GenType(..), TyNote(..),
- mkAppTy,
+import PprType ( pprType )
+import Type ( Type(..), Kind, ThetaType, TyNote(..),
+ mkAppTy, mkTyConApp,
splitDictTy_maybe, splitForAllTys,
- isTyVarTy, mkTyVarTys,
- fullSubstTy, substFlexiTy,
- boxedTypeKind, superKind
+ isTyVarTy, mkTyVarTy, mkTyVarTys,
+ fullSubstTy, substTopTy,
+ typeCon, openTypeKind, boxedTypeKind, boxedKind, superKind, superBoxity
)
+import TyCon ( tyConKind, mkPrimTyCon )
+import PrimRep ( PrimRep(VoidRep) )
import VarEnv
import VarSet ( emptyVarSet )
-import Var ( TyVar, GenTyVar, tyVarKind, tyVarFlexi, tyVarName,
- mkFlexiTyVar, removeTyVarFlexi, isFlexiTyVar, isTyVar
- )
+import Var ( TyVar, tyVarKind, tyVarName, isTyVar, isMutTyVar, mkTyVar )
-- others:
import TcMonad
-import Name ( changeUnique )
-
import TysWiredIn ( voidTy )
-import Name ( NamedThing(..), changeUnique, mkSysLocalName )
-import Unique ( Unique )
+import Name ( NamedThing(..), setNameUnique, mkSysLocalName,
+ mkDerivedName, mkDerivedTyConOcc
+ )
+import Unique ( Unique, Uniquable(..) )
import Util ( nOfThem )
import Outputable
\end{code}
-Data types
+Coercions
~~~~~~~~~~
-See TcMonad.lhs
+Type definitions are in TcMonad.lhs
\begin{code}
-tcTyVarToTyVar :: TcTyVar s -> TyVar
-tcTyVarToTyVar = removeTyVarFlexi
+typeToTcType :: Type -> TcType
+typeToTcType ty = ty
+
+kindToTcKind :: Kind -> TcKind
+kindToTcKind kind = kind
\end{code}
Utility functions
to a for-all type.
\begin{code}
-tcSplitRhoTy :: TcType s -> NF_TcM s (TcThetaType s, TcType s)
+tcSplitRhoTy :: TcType -> NF_TcM s (TcThetaType, TcType)
tcSplitRhoTy t
= go t t []
where
Just pair -> go res res (pair:ts)
Nothing -> returnNF_Tc (reverse ts, syn_t)
go syn_t (NoteTy _ t) ts = go syn_t t ts
- go syn_t (TyVarTy tv) ts = tcReadTyVar tv `thenNF_Tc` \ maybe_ty ->
+ go syn_t (TyVarTy tv) ts = tcGetTyVar tv `thenNF_Tc` \ maybe_ty ->
case maybe_ty of
- BoundTo ty | not (isTyVarTy ty) -> go syn_t ty ts
- other -> returnNF_Tc (reverse ts, syn_t)
+ Just ty | not (isTyVarTy ty) -> go syn_t ty ts
+ other -> returnNF_Tc (reverse ts, syn_t)
go syn_t t ts = returnNF_Tc (reverse ts, syn_t)
\end{code}
-New type variables
-~~~~~~~~~~~~~~~~~~
+%************************************************************************
+%* *
+\subsection{New type variables}
+%* *
+%************************************************************************
\begin{code}
-newTcTyVar :: Kind -> NF_TcM s (TcTyVar s)
-newTcTyVar kind
+newTyVar :: Kind -> NF_TcM s TcTyVar
+newTyVar kind
= tcGetUnique `thenNF_Tc` \ uniq ->
- tcNewMutVar UnBound `thenNF_Tc` \ box ->
- let
- name = mkSysLocalName uniq
- in
- returnNF_Tc (mkFlexiTyVar name kind box)
+ tcNewMutTyVar (mkSysLocalName uniq SLIT("t")) kind
-newTyVarTy :: Kind -> NF_TcM s (TcType s)
+newTyVarTy :: Kind -> NF_TcM s TcType
newTyVarTy kind
- = newTcTyVar kind `thenNF_Tc` \ tc_tyvar ->
+ = newTyVar kind `thenNF_Tc` \ tc_tyvar ->
returnNF_Tc (TyVarTy tc_tyvar)
-newTyVarTys :: Int -> Kind -> NF_TcM s [TcType s]
+newTyVarTys :: Int -> Kind -> NF_TcM s [TcType]
newTyVarTys n kind = mapNF_Tc newTyVarTy (nOfThem n kind)
-newKindVar :: NF_TcM s (TcKind s)
-newKindVar = newTyVarTy superKind
+newKindVar :: NF_TcM s TcKind
+newKindVar
+ = tcGetUnique `thenNF_Tc` \ uniq ->
+ tcNewMutTyVar (mkSysLocalName uniq SLIT("k")) superKind `thenNF_Tc` \ kv ->
+ returnNF_Tc (TyVarTy kv)
-newKindVars :: Int -> NF_TcM s [TcKind s]
+newKindVars :: Int -> NF_TcM s [TcKind]
newKindVars n = mapNF_Tc (\ _ -> newKindVar) (nOfThem n ())
+
+-- Returns a type variable of kind (Type bv) where bv is a new boxity var
+-- Used when you need a type variable that's definitely a , but you don't know
+-- what kind of type (boxed or unboxed).
+newTyVarTy_OpenKind :: NF_TcM s TcType
+newTyVarTy_OpenKind = newOpenTypeKind `thenNF_Tc` \ kind ->
+ newTyVarTy kind
+
+newOpenTypeKind :: NF_TcM s TcKind
+newOpenTypeKind = newTyVarTy superBoxity `thenNF_Tc` \ bv ->
+ returnNF_Tc (mkTyConApp typeCon [bv])
\end{code}
-Type instantiation
-~~~~~~~~~~~~~~~~~~
+
+%************************************************************************
+%* *
+\subsection{Type instantiation}
+%* *
+%************************************************************************
Instantiating a bunch of type variables
\begin{code}
-tcInstTyVars :: [GenTyVar flexi]
- -> NF_TcM s ([TcTyVar s], [TcType s], TyVarEnv (TcType s))
+tcInstTyVars :: [TyVar]
+ -> NF_TcM s ([TcTyVar], [TcType], TyVarEnv TcType)
tcInstTyVars tyvars
= mapNF_Tc inst_tyvar tyvars `thenNF_Tc` \ tc_tyvars ->
inst_tyvar tyvar -- Could use the name from the tyvar?
= tcGetUnique `thenNF_Tc` \ uniq ->
- tcNewMutVar UnBound `thenNF_Tc` \ box ->
let
- name = changeUnique (tyVarName tyvar) uniq
+ kind = tyVarKind tyvar
+ name = setNameUnique (tyVarName tyvar) uniq
-- Note that we don't change the print-name
-- This won't confuse the type checker but there's a chance
-- that two different tyvars will print the same way
-- Better watch out for this. If worst comes to worst, just
-- use mkSysLocalName.
in
- returnNF_Tc (mkFlexiTyVar name (tyVarKind tyvar) box)
+ tcNewMutTyVar name kind
\end{code}
@tcInstTcType@ instantiates the outer-level for-alls of a TcType with
fresh type variables, returning them and the instantiated body of the for-all.
-
\begin{code}
-tcInstTcType :: TcType s -> NF_TcM s ([TcTyVar s], TcType s)
+tcInstTcType :: TcType -> NF_TcM s ([TcTyVar], TcType)
tcInstTcType ty
- = let
- (tyvars, rho) = splitForAllTys ty
- in
- case tyvars of
- [] -> returnNF_Tc ([], ty) -- Nothing to do
- other -> tcInstTyVars tyvars `thenNF_Tc` \ (tyvars', _, tenv) ->
- returnNF_Tc (tyvars', fullSubstTy tenv emptyVarSet rho)
+ = case splitForAllTys ty of
+ ([], _) -> returnNF_Tc ([], ty) -- Nothing to do
+ (tyvars, rho) -> tcInstTyVars tyvars `thenNF_Tc` \ (tyvars', _, tenv) ->
+ returnNF_Tc (tyvars', fullSubstTy tenv emptyVarSet rho)
-- Since the tyvars are freshly made,
-- they cannot possibly be captured by
-- any existing for-alls. Hence emptyVarSet
\end{code}
-Sometimes we have to convert a Type to a TcType. I wonder whether we could
-do this less than we do?
-\begin{code}
-typeToTcType :: Type -> TcType s
-typeToTcType t = substFlexiTy emptyVarEnv t
-kindToTcKind :: Kind -> TcKind s
-kindToTcKind = typeToTcType
-\end{code}
+%************************************************************************
+%* *
+\subsection{Putting and getting mutable type variables}
+%* *
+%************************************************************************
-
-Reading and writing TcTyVars
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~
\begin{code}
-tcWriteTyVar :: TcTyVar s -> TcType s -> NF_TcM s ()
-tcReadTyVar :: TcTyVar s -> NF_TcM s (TcMaybe s)
+tcPutTyVar :: TcTyVar -> TcType -> NF_TcM s TcType
+tcGetTyVar :: TcTyVar -> NF_TcM s (Maybe TcType)
\end{code}
-Writing is easy:
+Putting is easy:
\begin{code}
-tcWriteTyVar tyvar ty = tcWriteMutVar (tyVarFlexi tyvar) (BoundTo ty)
+tcPutTyVar tyvar ty = tcWriteMutTyVar tyvar (Just ty) `thenNF_Tc_`
+ returnNF_Tc ty
\end{code}
-Reading is more interesting. The easy thing to do is just to read, thus:
+Getting is more interesting. The easy thing to do is just to read, thus:
+
\begin{verbatim}
-tcReadTyVar tyvar = tcReadMutVar (tyVarFlexi tyvar)
+tcGetTyVar tyvar = tcReadMutTyVar tyvar
\end{verbatim}
But it's more fun to short out indirections on the way: If this
We return Nothing iff the original box was unbound.
\begin{code}
-tcReadTyVar tyvar
- = tcReadMutVar box `thenNF_Tc` \ maybe_ty ->
+tcGetTyVar tyvar
+ = ASSERT2( isMutTyVar tyvar, ppr tyvar )
+ tcReadMutTyVar tyvar `thenNF_Tc` \ maybe_ty ->
case maybe_ty of
- BoundTo ty -> short_out ty `thenNF_Tc` \ ty' ->
- tcWriteMutVar box (BoundTo ty') `thenNF_Tc_`
- returnNF_Tc (BoundTo ty')
+ Just ty -> short_out ty `thenNF_Tc` \ ty' ->
+ tcWriteMutTyVar tyvar (Just ty') `thenNF_Tc_`
+ returnNF_Tc (Just ty')
- other -> returnNF_Tc other
- where
- box = tyVarFlexi tyvar
+ Nothing -> returnNF_Tc Nothing
-short_out :: TcType s -> NF_TcM s (TcType s)
+short_out :: TcType -> NF_TcM s TcType
short_out ty@(TyVarTy tyvar)
- = tcReadMutVar box `thenNF_Tc` \ maybe_ty ->
+ | not (isMutTyVar tyvar)
+ = returnNF_Tc ty
+
+ | otherwise
+ = tcReadMutTyVar tyvar `thenNF_Tc` \ maybe_ty ->
case maybe_ty of
- BoundTo ty' -> short_out ty' `thenNF_Tc` \ ty' ->
- tcWriteMutVar box (BoundTo ty') `thenNF_Tc_`
- returnNF_Tc ty'
+ Just ty' -> short_out ty' `thenNF_Tc` \ ty' ->
+ tcWriteMutTyVar tyvar (Just ty') `thenNF_Tc_`
+ returnNF_Tc ty'
- other -> returnNF_Tc ty
- where
- box = tyVarFlexi tyvar
+ other -> returnNF_Tc ty
short_out other_ty = returnNF_Tc other_ty
\end{code}
-Zonking Tc types to Tc types
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-\begin{code}
-zonkTcTyVars :: [TcTyVar s] -> NF_TcM s [TcType s]
-zonkTcTyVars tyvars = mapNF_Tc zonkTcTyVar tyvars
+%************************************************************************
+%* *
+\subsection{Zonking -- the exernal interfaces}
+%* *
+%************************************************************************
-zonkTcTyVar :: TcTyVar s -> NF_TcM s (TcType s)
-zonkTcTyVar tyvar
- | not (isFlexiTyVar tyvar) -- Not a flexi tyvar. This can happen when
- -- zonking a forall type, when the bound type variable
- -- needn't be a flexi.
- = ASSERT( isTyVar tyvar )
- returnNF_Tc (TyVarTy tyvar)
+----------------- Type variables
- | otherwise -- Is a flexi tyvar
- = tcReadTyVar tyvar `thenNF_Tc` \ maybe_ty ->
- case maybe_ty of
- BoundTo ty@(TyVarTy tyvar') -> returnNF_Tc ty -- tcReadTyVar never returns a bound tyvar
- BoundTo other -> zonkTcType other
- other -> returnNF_Tc (TyVarTy tyvar)
+\begin{code}
+zonkTcTyVars :: [TcTyVar] -> NF_TcM s [TcType]
+zonkTcTyVars tyvars = mapNF_Tc zonkTcTyVar tyvars
-zonkTcTyVarBndr :: TcTyVar s -> NF_TcM s (TcTyVar s)
+zonkTcTyVarBndr :: TcTyVar -> NF_TcM s TcTyVar
zonkTcTyVarBndr tyvar
= zonkTcTyVar tyvar `thenNF_Tc` \ (TyVarTy tyvar') ->
returnNF_Tc tyvar'
-zonkTcTypes :: [TcType s] -> NF_TcM s [TcType s]
+zonkTcTyVar :: TcTyVar -> NF_TcM s TcType
+zonkTcTyVar tyvar = zonkTyVar (\ tv -> returnNF_Tc (TyVarTy tv)) tyvar
+\end{code}
+
+----------------- Types
+
+\begin{code}
+zonkTcType :: TcType -> NF_TcM s TcType
+zonkTcType ty = zonkType (\ tv -> returnNF_Tc (TyVarTy tv)) ty
+
+zonkTcTypes :: [TcType] -> NF_TcM s [TcType]
zonkTcTypes tys = mapNF_Tc zonkTcType tys
-zonkTcThetaType :: TcThetaType s -> NF_TcM s (TcThetaType s)
+zonkTcThetaType :: TcThetaType -> NF_TcM s TcThetaType
zonkTcThetaType theta = mapNF_Tc zonk theta
where
- zonk (c,ts) = zonkTcTypes ts `thenNF_Tc` \ new_ts ->
- returnNF_Tc (c, new_ts)
+ zonk (c,ts) = zonkTcTypes ts `thenNF_Tc` \ new_ts ->
+ returnNF_Tc (c, new_ts)
-zonkTcKind :: TcKind s -> NF_TcM s (TcKind s)
+zonkTcKind :: TcKind -> NF_TcM s TcKind
zonkTcKind = zonkTcType
+\end{code}
-zonkTcType :: TcType s -> NF_TcM s (TcType s)
-
-zonkTcType (TyVarTy tyvar) = zonkTcTyVar tyvar
-
-zonkTcType (AppTy ty1 ty2)
- = zonkTcType ty1 `thenNF_Tc` \ ty1' ->
- zonkTcType ty2 `thenNF_Tc` \ ty2' ->
- returnNF_Tc (mkAppTy ty1' ty2')
-
-zonkTcType (TyConApp tc tys)
- = mapNF_Tc zonkTcType tys `thenNF_Tc` \ tys' ->
- returnNF_Tc (TyConApp tc tys')
-
-zonkTcType (NoteTy (SynNote ty1) ty2)
- = zonkTcType ty1 `thenNF_Tc` \ ty1' ->
- zonkTcType ty2 `thenNF_Tc` \ ty2' ->
- returnNF_Tc (NoteTy (SynNote ty1') ty2')
+------------------- These ...ToType, ...ToKind versions
+ are used at the end of type checking
-zonkTcType (NoteTy (FTVNote _) ty2) = zonkTcType ty2
+\begin{code}
+zonkTcKindToKind :: TcKind -> NF_TcM s Kind
+zonkTcKindToKind kind = zonkType zonk_unbound_kind_var kind
+ where
+ -- Zonk a mutable but unbound kind variable to
+ -- (Type Boxed) if it has kind superKind
+ -- Boxed if it has kind superBoxity
+ zonk_unbound_kind_var kv
+ | super_kind == superKind = tcPutTyVar kv boxedTypeKind
+ | otherwise = ASSERT( super_kind == superBoxity )
+ tcPutTyVar kv boxedKind
+ where
+ super_kind = tyVarKind kv
+
+
+zonkTcTypeToType :: TcType -> NF_TcM s Type
+zonkTcTypeToType ty = zonkType zonk_unbound_tyvar ty
+ where
+ -- Zonk a mutable but unbound type variable to
+ -- Void if it has kind (Type Boxed)
+ -- Voidxxx otherwise
+ zonk_unbound_tyvar tv
+ = zonkTcKindToKind (tyVarKind tv) `thenNF_Tc` \ kind ->
+ if kind == boxedTypeKind then
+ tcPutTyVar tv voidTy -- Just to avoid creating a new tycon in
+ -- this vastly common case
+ else
+ tcPutTyVar tv (TyConApp (mk_void_tycon tv kind) [])
+
+ mk_void_tycon tv kind -- Make a new TyCon with the same kind as the
+ -- type variable tv. Same name too, apart from
+ -- making it start with a colon (sigh)
+ = mkPrimTyCon tc_name kind 0 VoidRep
+ where
+ tc_name = mkDerivedName mkDerivedTyConOcc (getName tv) (getUnique tv)
+
+-- zonkTcTyVarToTyVar is applied to the *binding* occurrence
+-- of a type variable, at the *end* of type checking.
+-- It zonks the type variable, to get a mutable, but unbound, tyvar, tv;
+-- zonks its kind, and then makes an immutable version of tv and binds tv to it.
+-- Now any bound occurences of the original type variable will get
+-- zonked to the immutable version.
+
+zonkTcTyVarToTyVar :: TcTyVar -> NF_TcM s TyVar
+zonkTcTyVarToTyVar tv
+ = zonkTcKindToKind (tyVarKind tv) `thenNF_Tc` \ kind ->
+ let
+ -- Make an immutable version
+ immut_tv = mkTyVar (tyVarName tv) kind
+ immut_tv_ty = mkTyVarTy immut_tv
+
+ zap tv = tcPutTyVar tv immut_tv_ty
+ -- Bind the mutable version to the immutable one
+ in
+ -- If the type variable is mutable, then bind it to immut_tv_ty
+ -- so that all other occurrences of the tyvar will get zapped too
+ zonkTyVar zap tv `thenNF_Tc` \ ty2 ->
+ ASSERT2( immut_tv_ty == ty2, ppr tv $$ ppr immut_tv $$ ppr ty2 )
+
+ returnNF_Tc immut_tv
+\end{code}
-zonkTcType (ForAllTy tv ty)
- = zonkTcTyVar tv `thenNF_Tc` \ tv_ty ->
- zonkTcType ty `thenNF_Tc` \ ty' ->
- case tv_ty of -- Should be a tyvar!
- TyVarTy tv' -> returnNF_Tc (ForAllTy tv' ty')
- _ -> panic "zonkTcType"
- -- pprTrace "zonkTcType:ForAllTy:" (hsep [ppr tv, ppr tv_ty]) $
- -- returnNF_Tc (ForAllTy tv{-(tcTyVarToTyVar tv)-} ty')
-zonkTcType (FunTy ty1 ty2)
- = zonkTcType ty1 `thenNF_Tc` \ ty1' ->
- zonkTcType ty2 `thenNF_Tc` \ ty2' ->
- returnNF_Tc (FunTy ty1' ty2')
-\end{code}
+%************************************************************************
+%* *
+\subsection{Zonking -- the main work-horses: zonkType, zonkTyVar}
+%* *
+%* For internal use only! *
+%* *
+%************************************************************************
-Zonking Tc types to Type/Kind
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
\begin{code}
-zonkTcKindToKind :: TcKind s -> NF_TcM s Kind
-zonkTcKindToKind kind = zonkTcToType boxedTypeKind emptyVarEnv kind
+-- zonkType is used for Kinds as well
-zonkTcTypeToType :: TyVarEnv Type -> TcType s -> NF_TcM s Type
-zonkTcTypeToType env ty = zonkTcToType voidTy env ty
-
-zonkTcTyVarToTyVar :: TcTyVar s -> NF_TcM s TyVar
-zonkTcTyVarToTyVar tv
- = zonkTcTyVarBndr tv `thenNF_Tc` \ tv' ->
- returnNF_Tc (tcTyVarToTyVar tv')
+-- For unbound, mutable tyvars, zonkType uses the function given to it
+-- For tyvars bound at a for-all, zonkType zonks them to an immutable
+-- type variable and zonks the kind too
--- zonkTcToType is used for Kinds as well
-zonkTcToType :: Type -> TyVarEnv Type -> TcType s -> NF_TcM s Type
-zonkTcToType unbound_var_ty env ty
+zonkType :: (TcTyVar -> NF_TcM s Type) -- What to do with unbound mutable type variables
+ -- see zonkTcType, and zonkTcTypeToType
+ -> TcType
+ -> NF_TcM s Type
+zonkType unbound_var_fn ty
= go ty
where
go (TyConApp tycon tys) = mapNF_Tc go tys `thenNF_Tc` \ tys' ->
returnNF_Tc (mkAppTy fun' arg')
-- The two interesting cases!
- -- c.f. zonkTcTyVar
- go (TyVarTy tyvar)
- | not (isFlexiTyVar tyvar) = lookup env tyvar
-
- | otherwise = tcReadTyVar tyvar `thenNF_Tc` \ maybe_ty ->
- case maybe_ty of
- BoundTo (TyVarTy tyvar') -> lookup env tyvar'
- BoundTo other_ty -> go other_ty
- other -> lookup env tyvar
+ go (TyVarTy tyvar) = zonkTyVar unbound_var_fn tyvar
go (ForAllTy tyvar ty)
= zonkTcTyVarToTyVar tyvar `thenNF_Tc` \ tyvar' ->
- let
- new_env = extendVarEnv env tyvar (TyVarTy tyvar')
- in
- zonkTcToType unbound_var_ty new_env ty `thenNF_Tc` \ ty' ->
+ go ty `thenNF_Tc` \ ty' ->
returnNF_Tc (ForAllTy tyvar' ty')
- lookup env tyvar = returnNF_Tc (case lookupVarEnv env tyvar of
- Just ty -> ty
- Nothing -> unbound_var_ty)
+zonkTyVar :: (TcTyVar -> NF_TcM s Type) -- What to do for an unbound mutable variable
+ -> TcTyVar -> NF_TcM s TcType
+zonkTyVar unbound_var_fn tyvar
+ | not (isMutTyVar tyvar) -- Not a mutable tyvar. This can happen when
+ -- zonking a forall type, when the bound type variable
+ -- needn't be mutable
+ = ASSERT( isTyVar tyvar ) -- Should not be any immutable kind vars
+ returnNF_Tc (TyVarTy tyvar)
+
+ | otherwise
+ = tcGetTyVar tyvar `thenNF_Tc` \ maybe_ty ->
+ case maybe_ty of
+ Nothing -> unbound_var_fn tyvar -- Mutable and unbound
+ Just other_ty -> zonkType unbound_var_fn other_ty -- Bound
\end{code}
+%************************************************************************
+%* *
+\subsection{tcTypeKind}
+%* *
+%************************************************************************
+
+Sadly, we need a Tc version of typeKind, that looks though mutable
+kind variables. See the notes with Type.typeKind for the typeKindF nonsense
+
+This is pretty gruesome.
+\begin{code}
+tcTypeKind :: TcType -> NF_TcM s TcKind
+
+tcTypeKind (TyVarTy tyvar) = returnNF_Tc (tyVarKind tyvar)
+tcTypeKind (TyConApp tycon tys) = foldlTc (\k _ -> tcFunResultTy k) (tyConKind tycon) tys
+tcTypeKind (NoteTy _ ty) = tcTypeKind ty
+tcTypeKind (AppTy fun arg) = tcTypeKind fun `thenNF_Tc` \ fun_kind ->
+ tcFunResultTy fun_kind
+tcTypeKind (FunTy fun arg) = tcTypeKindF arg
+tcTypeKind (ForAllTy _ ty) = tcTypeKindF ty
+
+tcTypeKindF :: TcType -> NF_TcM s TcKind
+tcTypeKindF (NoteTy _ ty) = tcTypeKindF ty
+tcTypeKindF (FunTy _ ty) = tcTypeKindF ty
+tcTypeKindF (ForAllTy _ ty) = tcTypeKindF ty
+tcTypeKindF other = tcTypeKind other `thenNF_Tc` \ kind ->
+ fix_up kind
+ where
+ fix_up (TyConApp kc _) | kc == typeCon = returnNF_Tc boxedTypeKind
+ -- Functions at the type level are always boxed
+ fix_up (NoteTy _ kind) = fix_up kind
+ fix_up kind@(TyVarTy tv) = tcGetTyVar tv `thenNF_Tc` \ maybe_ty ->
+ case maybe_ty of
+ Just kind' -> fix_up kind'
+ Nothing -> returnNF_Tc kind
+ fix_up kind = returnNF_Tc kind
+
+tcFunResultTy (NoteTy _ ty) = tcFunResultTy ty
+tcFunResultTy (FunTy arg res) = returnNF_Tc res
+tcFunResultTy (TyVarTy tv) = tcGetTyVar tv `thenNF_Tc` \ maybe_ty ->
+ case maybe_ty of
+ Just ty' -> tcFunResultTy ty'
+ -- The Nothing case, and the other cases for tcFunResultTy
+ -- should never happen... pattern match failure
+\end{code}