zonkTcType, zonkTcTypes, zonkTcThetaType,
zonkTcKindToKind, zonkTcKind,
zonkImplication, zonkWanted, zonkEvVar, zonkWantedEvVar,
+ zonkTcTypeAndSubst,
tcGetGlobalTyVars,
readKindVar, writeKindVar
newMetaTyVar :: MetaInfo -> Kind -> TcM TcTyVar
-- Make a new meta tyvar out of thin air
newMetaTyVar meta_info kind
- = do { uniq <- newUnique
+ = do { uniq <- newMetaUnique
; ref <- newMutVar Flexi
; let name = mkSysTvName uniq fs
fs = case meta_info of
-- Make a new meta tyvar whose Name and Kind
-- come from an existing TyVar
instMetaTyVar meta_info tyvar
- = do { uniq <- newUnique
+ = do { uniq <- newMetaUnique
; ref <- newMutVar Flexi
; let name = setNameUnique (tyVarName tyvar) uniq
kind = tyVarKind tyvar
tcGetGlobalTyVars
= do { (TcLclEnv {tcl_tyvars = gtv_var}) <- getLclEnv
; gbl_tvs <- readMutVar gtv_var
- ; gbl_tvs' <- zonkTcTyVarsAndFV (varSetElems gbl_tvs)
+ ; gbl_tvs' <- zonkTcTyVarsAndFV gbl_tvs
; writeMutVar gtv_var gbl_tvs'
; return gbl_tvs' }
\end{code}
zonkTcTyVars :: [TcTyVar] -> TcM [TcType]
zonkTcTyVars tyvars = mapM zonkTcTyVar tyvars
-zonkTcTyVarsAndFV :: [TcTyVar] -> TcM TcTyVarSet
-zonkTcTyVarsAndFV tyvars = tyVarsOfTypes <$> mapM zonkTcTyVar tyvars
+zonkTcTyVarsAndFV :: TcTyVarSet -> TcM TcTyVarSet
+zonkTcTyVarsAndFV tyvars = tyVarsOfTypes <$> mapM zonkTcTyVar (varSetElems tyvars)
----------------- Types
zonkTcTypeCarefully :: TcType -> TcM TcType
+-- Do not zonk type variables free in the environment
zonkTcTypeCarefully ty
= do { env_tvs <- tcGetGlobalTyVars
- ; zonkType (zonkTcTyVarCarefully env_tvs) ty }
-
-
-zonkTcTyVarCarefully :: TcTyVarSet -> TcTyVar -> TcM TcType
--- Do not zonk type variables free in the environment
-zonkTcTyVarCarefully env_tvs tv
- | tv `elemVarSet` env_tvs
- = return (TyVarTy tv)
- | otherwise
- = ASSERT( isTcTyVar tv )
- case tcTyVarDetails tv of
- SkolemTv {} -> return (TyVarTy tv)
- FlatSkol ty -> zonkType (zonkTcTyVarCarefully env_tvs) ty
- MetaTv _ ref -> do { cts <- readMutVar ref
- ; case cts of
- Flexi -> return (TyVarTy tv)
- Indirect ty -> zonkType (zonkTcTyVarCarefully env_tvs) ty }
+ ; zonkType (zonk_tv env_tvs) ty }
+ where
+ zonk_tv env_tvs tv
+ | tv `elemVarSet` env_tvs
+ = return (TyVarTy tv)
+ | otherwise
+ = ASSERT( isTcTyVar tv )
+ case tcTyVarDetails tv of
+ SkolemTv {} -> return (TyVarTy tv)
+ FlatSkol ty -> zonkType (zonk_tv env_tvs) ty
+ MetaTv _ ref -> do { cts <- readMutVar ref
+ ; case cts of
+ Flexi -> return (TyVarTy tv)
+ Indirect ty -> zonkType (zonk_tv env_tvs) ty }
zonkTcType :: TcType -> TcM TcType
-- Simply look through all Flexis
zonkTcTyVar tv
= ASSERT2( isTcTyVar tv, ppr tv )
case tcTyVarDetails tv of
- SkolemTv {} -> return (TyVarTy tv)
+ SkolemTv {} -> return (TyVarTy tv)
FlatSkol ty -> zonkTcType ty
- MetaTv _ ref -> do { cts <- readMutVar ref
- ; case cts of
- Flexi -> return (TyVarTy tv)
- Indirect ty -> zonkTcType ty }
+ MetaTv _ ref -> do { cts <- readMutVar ref
+ ; case cts of
+ Flexi -> return (TyVarTy tv)
+ Indirect ty -> zonkTcType ty }
+
+zonkTcTypeAndSubst :: TvSubst -> TcType -> TcM TcType
+-- Zonk, and simultaneously apply a non-necessarily-idempotent substitution
+zonkTcTypeAndSubst subst ty = zonkType zonk_tv ty
+ where
+ zonk_tv tv
+ = case tcTyVarDetails tv of
+ SkolemTv {} -> return (TyVarTy tv)
+ FlatSkol ty -> zonkType zonk_tv ty
+ MetaTv _ ref -> do { cts <- readMutVar ref
+ ; case cts of
+ Flexi -> zonk_flexi tv
+ Indirect ty -> zonkType zonk_tv ty }
+ zonk_flexi tv
+ = case lookupTyVar subst tv of
+ Just ty -> zonkType zonk_tv ty
+ Nothing -> return (TyVarTy tv)
zonkTcTypes :: [TcType] -> TcM [TcType]
zonkTcTypes tys = mapM zonkTcType tys
-- Create the new, frozen, skolem type variable
-- We zonk to a skolem, not to a regular TcVar
-- See Note [Zonking to Skolem]
+ ; uniq <- newUnique -- Remove it from TcMetaTyVar unique land
; let final_kind = defaultKind (tyVarKind tv)
- final_tv = mkSkolTyVar (tyVarName tv) final_kind UnkSkol
+ final_name = setNameUnique (tyVarName tv) uniq
+ final_tv = mkSkolTyVar final_name final_kind UnkSkol
-- Bind the meta tyvar to the new tyvar
; case details of
\begin{code}
zonkImplication :: Implication -> TcM Implication
-zonkImplication implic@(Implic { ic_env_tvs = env_tvs, ic_given = given
+zonkImplication implic@(Implic { ic_given = given
, ic_wanted = wanted })
- = do { env_tvs' <- zonkTcTyVarsAndFV (varSetElems env_tvs)
- ; given' <- mapM zonkEvVar given
+ = do { given' <- mapM zonkEvVar given
; wanted' <- mapBagM zonkWanted wanted
- ; return (implic { ic_env_tvs = env_tvs', ic_given = given'
- , ic_wanted = wanted' }) }
+ ; return (implic { ic_given = given', ic_wanted = wanted' }) }
zonkEvVar :: EvVar -> TcM EvVar
zonkEvVar var = do { ty' <- zonkTcType (varType var)
mkZonkTcTyVar unbound_var_fn tyvar
= ASSERT( isTcTyVar tyvar )
case tcTyVarDetails tyvar of
- SkolemTv {} -> return (TyVarTy tyvar)
- FlatSkol ty -> zonkType (mkZonkTcTyVar unbound_var_fn) ty
- MetaTv _ ref -> do { cts <- readMutVar ref
- ; case cts of
- Flexi -> unbound_var_fn tyvar
- Indirect ty -> zonkType (mkZonkTcTyVar unbound_var_fn) ty }
+ SkolemTv {} -> return (TyVarTy tyvar)
+ FlatSkol ty -> zonkType (mkZonkTcTyVar unbound_var_fn) ty
+ MetaTv _ ref -> do { cts <- readMutVar ref
+ ; case cts of
+ Flexi -> unbound_var_fn tyvar
+ Indirect ty -> zonkType (mkZonkTcTyVar unbound_var_fn) ty }
-- Zonk the kind of a non-TC tyvar in case it is a coercion variable
-- (their kind contains types).
-- Size of a predicate
--
--- Equalities are a special case. The equality itself doesn't contribute to the
--- size and as we do not count class predicates, we have to start with one less.
--- This is easy to see considering that, given
--- class C a b | a -> b
--- type family F a
--- constraints (C a b) and (F a ~ b) are equivalent in size.
+-- We are considering whether *class* constraints terminate
+-- Once we get into an implicit parameter or equality we
+-- can't get back to a class constraint, so it's safe
+-- to say "size 0". See Trac #4200.
sizePred :: PredType -> Int
sizePred (ClassP _ tys') = sizeTypes tys'
-sizePred (IParam _ ty) = sizeType ty
-sizePred (EqPred ty1 ty2) = sizeType ty1 + sizeType ty2 - 1
+sizePred (IParam {}) = 0
+sizePred (EqPred {}) = 0
\end{code}
projects / ghc-hetmet.git / blobdiff