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-rw-r--r--ghc/compiler/typecheck/TcUnify.lhs131
1 files changed, 60 insertions, 71 deletions
diff --git a/ghc/compiler/typecheck/TcUnify.lhs b/ghc/compiler/typecheck/TcUnify.lhs
index d5323d82b9..cb4f73b32d 100644
--- a/ghc/compiler/typecheck/TcUnify.lhs
+++ b/ghc/compiler/typecheck/TcUnify.lhs
@@ -11,7 +11,7 @@ module TcUnify (
-- Various unifications
unifyTauTy, unifyTauTyList, unifyTauTyLists,
- unifyKind, unifyKinds, unifyOpenTypeKind, unifyFunKind,
+ unifyKind, unifyKinds, unifyTypeKind, unifyFunKind,
--------------------------------
-- Holes
@@ -30,12 +30,12 @@ module TcUnify (
import HsSyn ( HsExpr(..) )
import TcHsSyn ( mkHsLet,
ExprCoFn, idCoercion, isIdCoercion, mkCoercion, (<.>), (<$>) )
-import TypeRep ( Type(..), SourceType(..), TyNote(..), openKindCon )
+import TypeRep ( Type(..), PredType(..), TyNote(..), typeCon, openKindCon )
import TcRnMonad -- TcType, amongst others
import TcType ( TcKind, TcType, TcSigmaType, TcRhoType, TcTyVar, TcTauType,
TcTyVarSet, TcThetaType, TyVarDetails(SigTv),
- isTauTy, isSigmaTy, mkFunTys,
+ isTauTy, isSigmaTy, mkFunTys, mkTyConApp,
tcSplitAppTy_maybe, tcSplitTyConApp_maybe,
tcGetTyVar_maybe, tcGetTyVar,
mkFunTy, tyVarsOfType, mkPhiTy,
@@ -47,12 +47,12 @@ import TcType ( TcKind, TcType, TcSigmaType, TcRhoType, TcTyVar, TcTauType,
)
import Inst ( newDicts, instToId, tcInstCall )
import TcMType ( getTcTyVar, putTcTyVar, tcInstType, newKindVar,
- newTyVarTy, newTyVarTys, newOpenTypeKind,
+ newTyVarTy, newTyVarTys, newBoxityVar,
zonkTcType, zonkTcTyVars, zonkTcTyVarsAndFV )
import TcSimplify ( tcSimplifyCheck )
-import TysWiredIn ( listTyCon, parrTyCon, mkListTy, mkPArrTy, mkTupleTy )
+import TysWiredIn ( listTyCon, parrTyCon, tupleTyCon )
import TcEnv ( tcGetGlobalTyVars, findGlobals )
-import TyCon ( tyConArity, isTupleTyCon, tupleTyConBoxity )
+import TyCon ( TyCon, tyConArity, isTupleTyCon, tupleTyConBoxity )
import PprType ( pprType )
import Id ( Id, mkSysLocal )
import Var ( Var, varName, tyVarKind )
@@ -185,60 +185,46 @@ unify_fun_ty_help ty -- Special cases failed, so revert to ordinary unification
\end{code}
\begin{code}
-zapToListTy :: Expected TcType -- expected list type
- -> TcM TcType -- list element type
-
-zapToListTy (Check ty) = unifyListTy ty
-zapToListTy (Infer hole) = do { elt_ty <- newTyVarTy liftedTypeKind ;
- writeMutVar hole (mkListTy elt_ty) ;
+----------------------
+zapToListTy, zapToPArrTy :: Expected TcType -- expected list type
+ -> TcM TcType -- list element type
+unifyListTy, unifyPArrTy :: TcType -> TcM TcType
+zapToListTy = zapToXTy listTyCon
+unifyListTy = unifyXTy listTyCon
+zapToPArrTy = zapToXTy parrTyCon
+unifyPArrTy = unifyXTy parrTyCon
+
+----------------------
+zapToXTy :: TyCon -- T :: *->*
+ -> Expected TcType -- Expected type (T a)
+ -> TcM TcType -- Element type, a
+
+zapToXTy tc (Check ty) = unifyXTy tc ty
+zapToXTy tc (Infer hole) = do { elt_ty <- newTyVarTy liftedTypeKind ;
+ writeMutVar hole (mkTyConApp tc [elt_ty]) ;
return elt_ty }
-unifyListTy :: TcType -> TcM TcType
-unifyListTy ty@(TyVarTy tyvar)
+----------------------
+unifyXTy :: TyCon -> TcType -> TcM TcType
+unifyXTy tc ty@(TyVarTy tyvar)
= getTcTyVar tyvar `thenM` \ maybe_ty ->
case maybe_ty of
- Just ty' -> unifyListTy ty'
- other -> unify_list_ty_help ty
-
-unifyListTy ty
- = case tcSplitTyConApp_maybe ty of
- Just (tycon, [arg_ty]) | tycon == listTyCon -> returnM arg_ty
- other -> unify_list_ty_help ty
-
-unify_list_ty_help ty -- Revert to ordinary unification
- = newTyVarTy liftedTypeKind `thenM` \ elt_ty ->
- unifyTauTy ty (mkListTy elt_ty) `thenM_`
- returnM elt_ty
-
--- variant for parallel arrays
---
-zapToPArrTy :: Expected TcType -- Expected list type
- -> TcM TcType -- List element type
-
-zapToPArrTy (Check ty) = unifyPArrTy ty
-zapToPArrTy (Infer hole) = do { elt_ty <- newTyVarTy liftedTypeKind ;
- writeMutVar hole (mkPArrTy elt_ty) ;
- return elt_ty }
+ Just ty' -> unifyXTy tc ty'
+ other -> unify_x_ty_help tc ty
-unifyPArrTy :: TcType -> TcM TcType
-
-unifyPArrTy ty@(TyVarTy tyvar)
- = getTcTyVar tyvar `thenM` \ maybe_ty ->
- case maybe_ty of
- Just ty' -> unifyPArrTy ty'
- _ -> unify_parr_ty_help ty
-unifyPArrTy ty
+unifyXTy tc ty
= case tcSplitTyConApp_maybe ty of
- Just (tycon, [arg_ty]) | tycon == parrTyCon -> returnM arg_ty
- _ -> unify_parr_ty_help ty
+ Just (tycon, [arg_ty]) | tycon == tc -> returnM arg_ty
+ other -> unify_x_ty_help tc ty
-unify_parr_ty_help ty -- Revert to ordinary unification
- = newTyVarTy liftedTypeKind `thenM` \ elt_ty ->
- unifyTauTy ty (mkPArrTy elt_ty) `thenM_`
+unify_x_ty_help tc ty -- Revert to ordinary unification
+ = newTyVarTy liftedTypeKind `thenM` \ elt_ty ->
+ unifyTauTy ty (mkTyConApp tc [elt_ty]) `thenM_`
returnM elt_ty
\end{code}
\begin{code}
+----------------------
zapToTupleTy :: Boxity -> Arity -> Expected TcType -> TcM [TcType]
zapToTupleTy boxity arity (Check ty) = unifyTupleTy boxity arity ty
zapToTupleTy boxity arity (Infer hole) = do { (tup_ty, arg_tys) <- new_tuple_ty boxity arity ;
@@ -267,8 +253,9 @@ unify_tuple_ty_help boxity arity ty
new_tuple_ty boxity arity
= newTyVarTys arity kind `thenM` \ arg_tys ->
- return (mkTupleTy boxity arity arg_tys, arg_tys)
+ return (mkTyConApp tup_tc arg_tys, arg_tys)
where
+ tup_tc = tupleTyCon boxity arity
kind | isBoxed boxity = liftedTypeKind
| otherwise = openTypeKind
\end{code}
@@ -626,18 +613,20 @@ uTys ps_ty1 ty1 ps_ty2 (TyVarTy tyvar2) = uVar True tyvar2 ps_ty1 ty1
-- "True" means args swapped
-- Predicates
-uTys _ (SourceTy (IParam n1 t1)) _ (SourceTy (IParam n2 t2))
+uTys _ (PredTy (IParam n1 t1)) _ (PredTy (IParam n2 t2))
| n1 == n2 = uTys t1 t1 t2 t2
-uTys _ (SourceTy (ClassP c1 tys1)) _ (SourceTy (ClassP c2 tys2))
+uTys _ (PredTy (ClassP c1 tys1)) _ (PredTy (ClassP c2 tys2))
| c1 == c2 = unifyTauTyLists tys1 tys2
-uTys _ (SourceTy (NType tc1 tys1)) _ (SourceTy (NType tc2 tys2))
- | tc1 == tc2 = unifyTauTyLists tys1 tys2
-- Functions; just check the two parts
uTys _ (FunTy fun1 arg1) _ (FunTy fun2 arg2)
= uTys fun1 fun1 fun2 fun2 `thenM_` uTys arg1 arg1 arg2 arg2
- -- Type constructors must match
+ -- NewType constructors must match
+uTys _ (NewTcApp tc1 tys1) _ (NewTcApp tc2 tys2)
+ | tc1 == tc2 = unifyTauTyLists tys1 tys2
+
+ -- Ordinary type constructors must match
uTys ps_ty1 (TyConApp con1 tys1) ps_ty2 (TyConApp con2 tys2)
| con1 == con2 && equalLength tys1 tys2
= unifyTauTyLists tys1 tys2
@@ -646,7 +635,7 @@ uTys ps_ty1 (TyConApp con1 tys1) ps_ty2 (TyConApp con2 tys2)
-- When we are doing kind checking, we might match a kind '?'
-- against a kind '*' or '#'. Notably, CCallable :: ? -> *, and
-- (CCallable Int) and (CCallable Int#) are both OK
- = unifyOpenTypeKind ps_ty2
+ = unifyTypeKind ps_ty2
-- Applications need a bit of care!
-- They can match FunTy and TyConApp, so use splitAppTy_maybe
@@ -887,8 +876,9 @@ okToUnifyWith tv ty
ok (AppTy t1 t2) = ok t1 `and` ok t2
ok (FunTy t1 t2) = ok t1 `and` ok t2
ok (TyConApp _ ts) = oks ts
+ ok (NewTcApp _ ts) = oks ts
ok (ForAllTy _ _) = Just NotMonoType
- ok (SourceTy st) = ok_st st
+ ok (PredTy st) = ok_st st
ok (NoteTy (FTVNote _) t) = ok t
ok (NoteTy (SynNote t1) t2) = ok t1 `and` ok t2
-- Type variables may be free in t1 but not t2
@@ -898,7 +888,6 @@ okToUnifyWith tv ty
ok_st (ClassP _ ts) = oks ts
ok_st (IParam _ t) = ok t
- ok_st (NType _ ts) = oks ts
Nothing `and` m = m
Just p `and` m = Just p
@@ -924,23 +913,23 @@ unifyKinds _ _ = panic "unifyKinds: length mis-match"
\end{code}
\begin{code}
-unifyOpenTypeKind :: TcKind -> TcM ()
--- Ensures that the argument kind is of the form (Type bx)
--- for some boxity bx
+unifyTypeKind :: TcKind -> TcM ()
+-- Ensures that the argument kind is a liftedTypeKind or unliftedTypeKind
+-- If it's a kind variable, make it (Type bx), for a fresh boxity variable bx
-unifyOpenTypeKind ty@(TyVarTy tyvar)
+unifyTypeKind ty@(TyVarTy tyvar)
= getTcTyVar tyvar `thenM` \ maybe_ty ->
case maybe_ty of
- Just ty' -> unifyOpenTypeKind ty'
- other -> unify_open_kind_help ty
-
-unifyOpenTypeKind ty
+ Just ty' -> unifyTypeKind ty'
+ Nothing -> newBoxityVar `thenM` \ bx_var ->
+ putTcTyVar tyvar (mkTyConApp typeCon [bx_var]) `thenM_`
+ returnM ()
+
+unifyTypeKind ty
| isTypeKind ty = returnM ()
- | otherwise = unify_open_kind_help ty
-
-unify_open_kind_help ty -- Revert to ordinary unification
- = newOpenTypeKind `thenM` \ open_kind ->
- unifyKind ty open_kind
+ | otherwise -- Failure
+ = zonkTcType ty `thenM` \ ty1 ->
+ failWithTc (ptext SLIT("Type expected but") <+> quotes (ppr ty1) <+> ptext SLIT("found"))
\end{code}
\begin{code}
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