X-Git-Url: http://git.megacz.com/?p=ghc-hetmet.git;a=blobdiff_plain;f=compiler%2Ftypecheck%2FTcUnify.lhs;h=0dfe3941c53d0f2c9eafe18cbf2cca60414e7d9f;hp=4fc50b33256e642b0331aad8a57854d9d44a0a8a;hb=fdf8656855d26105ff36bdd24d41827b05037b91;hpb=a52ff7619e8b7d74a9d933d922eeea49f580bca8 diff --git a/compiler/typecheck/TcUnify.lhs b/compiler/typecheck/TcUnify.lhs index 4fc50b3..0dfe394 100644 --- a/compiler/typecheck/TcUnify.lhs +++ b/compiler/typecheck/TcUnify.lhs @@ -28,7 +28,7 @@ module TcUnify ( import HsSyn import TypeRep import CoreUtils( mkPiTypes ) -import TcErrors ( unifyCtxt ) +import TcErrors ( unifyCtxt ) import TcMType import TcIface import TcRnMonad @@ -44,7 +44,6 @@ import VarEnv import Name import ErrUtils import BasicTypes - import Maybes ( allMaybes ) import Util import Outputable @@ -103,7 +102,7 @@ expected type, becuase it expects that to have been done already matchExpectedFunTys :: SDoc -- See Note [Herald for matchExpectedFunTys] -> Arity -> TcRhoType - -> TcM (CoercionI, [TcSigmaType], TcRhoType) + -> TcM (Coercion, [TcSigmaType], TcRhoType) -- If matchExpectFunTys n ty = (co, [t1,..,tn], ty_r) -- then co : ty ~ (t1 -> ... -> tn -> ty_r) @@ -122,7 +121,7 @@ matchExpectedFunTys herald arity orig_ty -- then co : ty ~ t1 -> .. -> tn -> ty_r go n_req ty - | n_req == 0 = return (IdCo ty, [], ty) + | n_req == 0 = return (mkReflCo ty, [], ty) go n_req ty | Just ty' <- tcView ty = go n_req ty' @@ -130,7 +129,7 @@ matchExpectedFunTys herald arity orig_ty go n_req (FunTy arg_ty res_ty) | not (isPredTy arg_ty) = do { (coi, tys, ty_r) <- go (n_req-1) res_ty - ; return (mkFunTyCoI (IdCo arg_ty) coi, arg_ty:tys, ty_r) } + ; return (mkFunCo (mkReflCo arg_ty) coi, arg_ty:tys, ty_r) } go _ (TyConApp tc _) -- A common case | not (isSynFamilyTyCon tc) @@ -173,14 +172,14 @@ matchExpectedFunTys herald arity orig_ty \begin{code} ---------------------- -matchExpectedListTy :: TcRhoType -> TcM (CoercionI, TcRhoType) +matchExpectedListTy :: TcRhoType -> TcM (Coercion, TcRhoType) -- Special case for lists matchExpectedListTy exp_ty = do { (coi, [elt_ty]) <- matchExpectedTyConApp listTyCon exp_ty ; return (coi, elt_ty) } ---------------------- -matchExpectedPArrTy :: TcRhoType -> TcM (CoercionI, TcRhoType) +matchExpectedPArrTy :: TcRhoType -> TcM (Coercion, TcRhoType) -- Special case for parrs matchExpectedPArrTy exp_ty = do { (coi, [elt_ty]) <- matchExpectedTyConApp parrTyCon exp_ty @@ -189,7 +188,7 @@ matchExpectedPArrTy exp_ty ---------------------- matchExpectedTyConApp :: TyCon -- T :: k1 -> ... -> kn -> * -> TcRhoType -- orig_ty - -> TcM (CoercionI, -- T a b c ~ orig_ty + -> TcM (Coercion, -- T a b c ~ orig_ty [TcSigmaType]) -- Element types, a b c -- It's used for wired-in tycons, so we call checkWiredInTyCon @@ -200,7 +199,7 @@ matchExpectedTyConApp tc orig_ty = do { checkWiredInTyCon tc ; go (tyConArity tc) orig_ty [] } where - go :: Int -> TcRhoType -> [TcSigmaType] -> TcM (CoercionI, [TcSigmaType]) + go :: Int -> TcRhoType -> [TcSigmaType] -> TcM (Coercion, [TcSigmaType]) -- If go n ty tys = (co, [t1..tn] ++ tys) -- then co : T t1..tn ~ ty @@ -217,12 +216,12 @@ matchExpectedTyConApp tc orig_ty go n_req ty@(TyConApp tycon args) tys | tc == tycon = ASSERT( n_req == length args) -- ty::* - return (IdCo ty, args ++ tys) + return (mkReflCo ty, args ++ tys) go n_req (AppTy fun arg) tys | n_req > 0 = do { (coi, args) <- go (n_req - 1) fun (arg : tys) - ; return (mkAppTyCoI coi (IdCo arg), args) } + ; return (mkAppCo coi (mkReflCo arg), args) } go n_req ty tys = defer n_req ty tys @@ -236,7 +235,7 @@ matchExpectedTyConApp tc orig_ty ---------------------- matchExpectedAppTy :: TcRhoType -- orig_ty - -> TcM (CoercionI, -- m a ~ orig_ty + -> TcM (Coercion, -- m a ~ orig_ty (TcSigmaType, TcSigmaType)) -- Returns m, a -- If the incoming type is a mutable type variable of kind k, then -- matchExpectedAppTy returns a new type variable (m: * -> k); note the *. @@ -248,7 +247,7 @@ matchExpectedAppTy orig_ty | Just ty' <- tcView ty = go ty' | Just (fun_ty, arg_ty) <- tcSplitAppTy_maybe ty - = return (IdCo orig_ty, (fun_ty, arg_ty)) + = return (mkReflCo orig_ty, (fun_ty, arg_ty)) go (TyVarTy tv) | ASSERT( isTcTyVar tv) isMetaTyVar tv @@ -306,14 +305,14 @@ tcSubType origin ctxt ty_actual ty_expected <- tcGen ctxt ty_expected $ \ _ sk_rho -> do { (in_wrap, in_rho) <- deeplyInstantiate origin ty_actual ; coi <- unifyType in_rho sk_rho - ; return (coiToHsWrapper coi <.> in_wrap) } + ; return (coToHsWrapper coi <.> in_wrap) } ; return (sk_wrap <.> inst_wrap) } | otherwise -- Urgh! It seems deeply weird to have equality -- when actual is not a polytype, and it makes a big -- difference e.g. tcfail104 = do { coi <- unifyType ty_actual ty_expected - ; return (coiToHsWrapper coi) } + ; return (coToHsWrapper coi) } tcInfer :: (TcType -> TcM a) -> TcM (a, TcType) tcInfer tc_infer = do { ty <- newFlexiTyVarTy openTypeKind @@ -325,7 +324,7 @@ tcWrapResult :: HsExpr TcId -> TcRhoType -> TcRhoType -> TcM (HsExpr TcId) tcWrapResult expr actual_ty res_ty = do { coi <- unifyType actual_ty res_ty -- Both types are deeply skolemised - ; return (mkHsWrapCoI coi expr) } + ; return (mkHsWrapCo coi expr) } ----------------------------------- wrapFunResCoercion @@ -451,18 +450,18 @@ non-exported generic functions. \begin{code} --------------- -unifyType :: TcTauType -> TcTauType -> TcM CoercionI +unifyType :: TcTauType -> TcTauType -> TcM Coercion -- Actual and expected types -- Returns a coercion : ty1 ~ ty2 unifyType ty1 ty2 = uType [] ty1 ty2 --------------- -unifyPred :: PredType -> PredType -> TcM CoercionI +unifyPred :: PredType -> PredType -> TcM Coercion -- Actual and expected types unifyPred p1 p2 = uPred [UnifyOrigin (mkPredTy p1) (mkPredTy p2)] p1 p2 --------------- -unifyTheta :: TcThetaType -> TcThetaType -> TcM [CoercionI] +unifyTheta :: TcThetaType -> TcThetaType -> TcM [Coercion] -- Actual and expected types unifyTheta theta1 theta2 = do { checkTc (equalLength theta1 theta2) @@ -513,7 +512,7 @@ uType, uType_np, uType_defer :: [EqOrigin] -> TcType -- ty1 is the *actual* type -> TcType -- ty2 is the *expected* type - -> TcM CoercionI + -> TcM Coercion -------------- -- It is always safe to defer unification to the main constraint solver @@ -529,7 +528,7 @@ uType_defer (item : origin) ty1 ty2 ; doc <- mkErrInfo emptyTidyEnv ctxt ; traceTc "utype_defer" (vcat [ppr co_var, ppr ty1, ppr ty2, ppr origin, doc]) - ; return $ ACo $ mkTyVarTy co_var } + ; return $ mkCoVarCo co_var } uType_defer [] _ _ = panic "uType_defer" @@ -545,15 +544,15 @@ uType_np origin orig_ty1 orig_ty2 [ sep [ ppr orig_ty1, text "~", ppr orig_ty2] , ppr origin] ; coi <- go orig_ty1 orig_ty2 - ; case coi of - ACo co -> traceTc "u_tys yields coercion:" (ppr co) - IdCo _ -> traceTc "u_tys yields no coercion" empty + ; if isReflCo coi + then traceTc "u_tys yields no coercion" empty + else traceTc "u_tys yields coercion:" (ppr coi) ; return coi } where bale_out :: [EqOrigin] -> TcM a bale_out origin = failWithMisMatch origin - go :: TcType -> TcType -> TcM CoercionI + go :: TcType -> TcType -> TcM Coercion -- The arguments to 'go' are always semantically identical -- to orig_ty{1,2} except for looking through type synonyms @@ -579,24 +578,14 @@ uType_np origin orig_ty1 orig_ty2 | Just ty1' <- tcView ty1 = go ty1' ty2 | Just ty2' <- tcView ty2 = go ty1 ty2' - -- Predicates go (PredTy p1) (PredTy p2) = uPred origin p1 p2 - -- Coercion functions: (t1a ~ t1b) => t1c ~ (t2a ~ t2b) => t2c - go ty1 ty2 - | Just (t1a,t1b,t1c) <- splitCoPredTy_maybe ty1, - Just (t2a,t2b,t2c) <- splitCoPredTy_maybe ty2 - = do { co1 <- uType origin t1a t2a - ; co2 <- uType origin t1b t2b - ; co3 <- uType origin t1c t2c - ; return $ mkCoPredCoI co1 co2 co3 } - -- Functions (or predicate functions) just check the two parts go (FunTy fun1 arg1) (FunTy fun2 arg2) = do { coi_l <- uType origin fun1 fun2 ; coi_r <- uType origin arg1 arg2 - ; return $ mkFunTyCoI coi_l coi_r } + ; return $ mkFunCo coi_l coi_r } -- Always defer if a type synonym family (type function) -- is involved. (Data families behave rigidly.) @@ -608,20 +597,20 @@ uType_np origin orig_ty1 orig_ty2 go (TyConApp tc1 tys1) (TyConApp tc2 tys2) | tc1 == tc2 -- See Note [TyCon app] = do { cois <- uList origin uType tys1 tys2 - ; return $ mkTyConAppCoI tc1 cois } + ; return $ mkTyConAppCo tc1 cois } -- See Note [Care with type applications] go (AppTy s1 t1) ty2 | Just (s2,t2) <- tcSplitAppTy_maybe ty2 = do { coi_s <- uType_np origin s1 s2 -- See Note [Unifying AppTy] ; coi_t <- uType origin t1 t2 - ; return $ mkAppTyCoI coi_s coi_t } + ; return $ mkAppCo coi_s coi_t } go ty1 (AppTy s2 t2) | Just (s1,t1) <- tcSplitAppTy_maybe ty1 = do { coi_s <- uType_np origin s1 s2 ; coi_t <- uType origin t1 t2 - ; return $ mkAppTyCoI coi_s coi_t } + ; return $ mkAppCo coi_s coi_t } go ty1 ty2 | tcIsForAllTy ty1 || tcIsForAllTy ty2 @@ -630,7 +619,7 @@ uType_np origin orig_ty1 orig_ty2 -- Anything else fails go _ _ = bale_out origin -unifySigmaTy :: [EqOrigin] -> TcType -> TcType -> TcM CoercionI +unifySigmaTy :: [EqOrigin] -> TcType -> TcType -> TcM Coercion unifySigmaTy origin ty1 ty2 = do { let (tvs1, body1) = tcSplitForAllTys ty1 (tvs2, body2) = tcSplitForAllTys ty2 @@ -639,9 +628,8 @@ unifySigmaTy origin ty1 ty2 -- Get location from monad, not from tvs1 ; let tys = mkTyVarTys skol_tvs in_scope = mkInScopeSet (mkVarSet skol_tvs) - phi1 = substTy (mkTvSubst in_scope (zipTyEnv tvs1 tys)) body1 - phi2 = substTy (mkTvSubst in_scope (zipTyEnv tvs2 tys)) body2 --- untch = tyVarsOfType ty1 `unionVarSet` tyVarsOfType ty2 + phi1 = Type.substTy (mkTvSubst in_scope (zipTyEnv tvs1 tys)) body1 + phi2 = Type.substTy (mkTvSubst in_scope (zipTyEnv tvs2 tys)) body2 ; ((coi, _untch), lie) <- captureConstraints $ captureUntouchables $ @@ -656,23 +644,24 @@ unifySigmaTy origin ty1 ty2 (failWithMisMatch origin) -- ToDo: give details from bad_lie ; emitConstraints lie - ; return (foldr mkForAllTyCoI coi skol_tvs) } + ; return (foldr mkForAllCo coi skol_tvs) } ---------- -uPred :: [EqOrigin] -> PredType -> PredType -> TcM CoercionI +uPred :: [EqOrigin] -> PredType -> PredType -> TcM Coercion uPred origin (IParam n1 t1) (IParam n2 t2) | n1 == n2 = do { coi <- uType origin t1 t2 - ; return $ mkIParamPredCoI n1 coi } + ; return $ mkPredCo $ IParam n1 coi } uPred origin (ClassP c1 tys1) (ClassP c2 tys2) | c1 == c2 = do { cois <- uList origin uType tys1 tys2 -- Guaranteed equal lengths because the kinds check - ; return $ mkClassPPredCoI c1 cois } + ; return $ mkPredCo $ ClassP c1 cois } + uPred origin (EqPred ty1a ty1b) (EqPred ty2a ty2b) - = do { coia <- uType origin ty1a ty2a - ; coib <- uType origin ty1b ty2b - ; return $ mkEqPredCoI coia coib } + = do { coa <- uType origin ty1a ty2a + ; cob <- uType origin ty1b ty2b + ; return $ mkPredCo $ EqPred coa cob } uPred origin _ _ = failWithMisMatch origin @@ -816,7 +805,7 @@ of the substitution; rather, notice that @uVar@ (defined below) nips back into @uTys@ if it turns out that the variable is already bound. \begin{code} -uVar :: [EqOrigin] -> SwapFlag -> TcTyVar -> TcTauType -> TcM CoercionI +uVar :: [EqOrigin] -> SwapFlag -> TcTyVar -> TcTauType -> TcM Coercion uVar origin swapped tv1 ty2 = do { traceTc "uVar" (vcat [ ppr origin , ppr swapped @@ -834,13 +823,13 @@ uUnfilledVar :: [EqOrigin] -> SwapFlag -> TcTyVar -> TcTyVarDetails -- Tyvar 1 -> TcTauType -- Type 2 - -> TcM CoercionI + -> TcM Coercion -- "Unfilled" means that the variable is definitely not a filled-in meta tyvar -- It might be a skolem, or untouchable, or meta uUnfilledVar origin swapped tv1 details1 (TyVarTy tv2) | tv1 == tv2 -- Same type variable => no-op - = return (IdCo (mkTyVarTy tv1)) + = return (mkReflCo (mkTyVarTy tv1)) | otherwise -- Distinct type variables = do { lookup2 <- lookupTcTyVar tv2 @@ -874,7 +863,7 @@ uUnfilledVars :: [EqOrigin] -> SwapFlag -> TcTyVar -> TcTyVarDetails -- Tyvar 1 -> TcTyVar -> TcTyVarDetails -- Tyvar 2 - -> TcM CoercionI + -> TcM Coercion -- Invarant: The type variables are distinct, -- Neither is filled in yet @@ -1053,10 +1042,10 @@ lookupTcTyVar tyvar details = ASSERT2( isTcTyVar tyvar, ppr tyvar ) tcTyVarDetails tyvar -updateMeta :: TcTyVar -> TcRef MetaDetails -> TcType -> TcM CoercionI +updateMeta :: TcTyVar -> TcRef MetaDetails -> TcType -> TcM Coercion updateMeta tv1 ref1 ty2 = do { writeMetaTyVarRef tv1 ref1 ty2 - ; return (IdCo ty2) } + ; return (mkReflCo ty2) } \end{code} Note [Unifying untouchables]