X-Git-Url: http://git.megacz.com/?p=ghc-hetmet.git;a=blobdiff_plain;f=compiler%2Ftypecheck%2FTcPat.lhs;h=8304a22ddbe20cdf95fb0fff6824a2543c518ee4;hp=d28e901325e6c3de4f85802248260e02bb137f16;hb=HEAD;hpb=27310213397bb89555bb03585e057ba1b017e895 diff --git a/compiler/typecheck/TcPat.lhs b/compiler/typecheck/TcPat.lhs index d28e901..8304a22 100644 --- a/compiler/typecheck/TcPat.lhs +++ b/compiler/typecheck/TcPat.lhs @@ -36,7 +36,6 @@ import PrelNames import BasicTypes hiding (SuccessFlag(..)) import DynFlags import SrcLoc -import ErrUtils import Util import Outputable import FastString @@ -149,7 +148,7 @@ data TcSigInfo instance Outputable TcSigInfo where ppr (TcSigInfo { sig_id = id, sig_tvs = tyvars, sig_theta = theta, sig_tau = tau}) - = ppr id <+> ptext (sLit "::") <+> ppr tyvars <+> pprThetaArrow theta <+> ppr tau + = ppr id <+> ptext (sLit "::") <+> ppr tyvars <+> pprThetaArrowTy theta <+> ppr tau \end{code} Note [sig_tau may be polymorphic] @@ -193,7 +192,7 @@ res_ty free vars. %************************************************************************ \begin{code} -tcPatBndr :: PatEnv -> Name -> TcSigmaType -> TcM (CoercionI, TcId) +tcPatBndr :: PatEnv -> Name -> TcSigmaType -> TcM (Coercion, TcId) -- (coi, xp) = tcPatBndr penv x pat_ty -- Then coi : pat_ty ~ typeof(xp) -- @@ -205,11 +204,11 @@ tcPatBndr (PE { pe_ctxt = LetPat lookup_sig no_gen}) bndr_name pat_ty | otherwise = do { bndr_id <- newNoSigLetBndr no_gen bndr_name pat_ty - ; return (IdCo pat_ty, bndr_id) } + ; return (mkReflCo pat_ty, bndr_id) } tcPatBndr (PE { pe_ctxt = _lam_or_proc }) bndr_name pat_ty = do { bndr <- mkLocalBinder bndr_name pat_ty - ; return (IdCo pat_ty, bndr) } + ; return (mkReflCo pat_ty, bndr) } ------------ newSigLetBndr :: LetBndrSpec -> Name -> TcSigInfo -> TcM TcId @@ -348,9 +347,9 @@ tc_lpat :: LPat Name -> TcM a -> TcM (LPat TcId, a) tc_lpat (L span pat) pat_ty penv thing_inside - = setSrcSpan span $ - maybeAddErrCtxt (patCtxt pat) $ - do { (pat', res) <- tc_pat penv pat pat_ty thing_inside + = setSrcSpan span $ + do { (pat', res) <- maybeWrapPatCtxt pat (tc_pat penv pat pat_ty) + thing_inside ; return (L span pat', res) } tc_lpats :: PatEnv @@ -373,7 +372,7 @@ tc_pat :: PatEnv tc_pat penv (VarPat name) pat_ty thing_inside = do { (coi, id) <- tcPatBndr penv name pat_ty ; res <- tcExtendIdEnv1 name id thing_inside - ; return (mkHsWrapPatCoI coi (VarPat id) pat_ty, res) } + ; return (mkHsWrapPatCo coi (VarPat id) pat_ty, res) } tc_pat penv (ParPat pat) pat_ty thing_inside = do { (pat', res) <- tc_lpat pat pat_ty penv thing_inside @@ -423,7 +422,7 @@ tc_pat penv (AsPat (L nm_loc name) pat) pat_ty thing_inside -- perhaps be fixed, but only with a bit more work. -- -- If you fix it, don't forget the bindInstsOfPatIds! - ; return (mkHsWrapPatCoI coi (AsPat (L nm_loc bndr_id) pat') pat_ty, res) } + ; return (mkHsWrapPatCo coi (AsPat (L nm_loc bndr_id) pat') pat_ty, res) } tc_pat penv vpat@(ViewPat expr pat _) overall_pat_ty thing_inside = do { checkUnboxedTuple overall_pat_ty $ @@ -448,7 +447,7 @@ tc_pat penv vpat@(ViewPat expr pat _) overall_pat_ty thing_inside -- pattern must have pat_ty ; (pat', res) <- tc_lpat pat pat_ty penv thing_inside - ; return (ViewPat (mkLHsWrapCoI expr_coi expr') pat' overall_pat_ty, res) } + ; return (ViewPat (mkLHsWrapCo expr_coi expr') pat' overall_pat_ty, res) } -- Type signatures in patterns -- See Note [Pattern coercions] below @@ -459,9 +458,6 @@ tc_pat penv (SigPatIn pat sig_ty) pat_ty thing_inside ; return (mkHsWrapPat wrap (SigPatOut pat' inner_ty) pat_ty, res) } -tc_pat _ pat@(TypePat _) _ _ - = failWithTc (badTypePat pat) - ------------------------ -- Lists, tuples, arrays tc_pat penv (ListPat pats _) pat_ty thing_inside @@ -511,7 +507,7 @@ tc_pat _ (LitPat simple_lit) pat_ty thing_inside ; coi <- unifyPatType lit_ty pat_ty -- coi is of kind: pat_ty ~ lit_ty ; res <- thing_inside - ; return ( mkHsWrapPatCoI coi (LitPat simple_lit) pat_ty + ; return ( mkHsWrapPatCo coi (LitPat simple_lit) pat_ty , res) } ------------------------ @@ -546,19 +542,19 @@ tc_pat penv (NPlusKPat (L nm_loc name) lit ge minus) pat_ty thing_inside ; instStupidTheta orig [mkClassPred icls [pat_ty']] ; res <- tcExtendIdEnv1 name bndr_id thing_inside - ; return (mkHsWrapPatCoI coi pat' pat_ty, res) } + ; return (mkHsWrapPatCo coi pat' pat_ty, res) } tc_pat _ _other_pat _ _ = panic "tc_pat" -- ConPatOut, SigPatOut ---------------- -unifyPatType :: TcType -> TcType -> TcM CoercionI +unifyPatType :: TcType -> TcType -> TcM Coercion -- In patterns we want a coercion from the -- context type (expected) to the actual pattern type -- But we don't want to reverse the args to unifyType because -- that controls the actual/expected stuff in error messages unifyPatType actual_ty expected_ty = do { coi <- unifyType actual_ty expected_ty - ; return (mkSymCoI coi) } + ; return (mkSymCo coi) } \end{code} Note [Hopping the LIE in lazy patterns] @@ -657,7 +653,7 @@ tcConPat penv (L con_span con_name) pat_ty arg_pats thing_inside = do { data_con <- tcLookupDataCon con_name ; let tycon = dataConTyCon data_con -- For data families this is the representation tycon - (univ_tvs, ex_tvs, eq_spec, eq_theta, dict_theta, arg_tys, _) + (univ_tvs, ex_tvs, eq_spec, theta, arg_tys, _) = dataConFullSig data_con -- Instantiate the constructor type variables [a->ty] @@ -679,9 +675,8 @@ tcConPat penv (L con_span con_name) pat_ty arg_pats thing_inside tenv = zipTopTvSubst (univ_tvs ++ ex_tvs) (ctxt_res_tys ++ mkTyVarTys ex_tvs') arg_tys' = substTys tenv arg_tys - full_theta = eq_theta ++ dict_theta - ; if null ex_tvs && null eq_spec && null full_theta + ; if null ex_tvs && null eq_spec && null theta then do { -- The common case; no class bindings etc -- (see Note [Arrows and patterns]) (arg_pats', res) <- tcConArgs data_con arg_tys' @@ -696,8 +691,7 @@ tcConPat penv (L con_span con_name) pat_ty arg_pats thing_inside else do -- The general case, with existential, -- and local equality constraints - { let eq_preds = [mkEqPred (mkTyVarTy tv, ty) | (tv, ty) <- eq_spec] - theta' = substTheta tenv (eq_preds ++ full_theta) + { let theta' = substTheta tenv (eqSpecPreds eq_spec ++ theta) -- order is *important* as we generate the list of -- dictionary binders from theta' no_equalities = not (any isEqPred theta') @@ -726,21 +720,21 @@ tcConPat penv (L con_span con_name) pat_ty arg_pats thing_inside } } ---------------------------- -matchExpectedPatTy :: (TcRhoType -> TcM (CoercionI, a)) +matchExpectedPatTy :: (TcRhoType -> TcM (Coercion, a)) -> TcRhoType -> TcM (HsWrapper, a) -- See Note [Matching polytyped patterns] -- Returns a wrapper : pat_ty ~ inner_ty matchExpectedPatTy inner_match pat_ty | null tvs && null theta = do { (coi, res) <- inner_match pat_ty - ; return (coiToHsWrapper (mkSymCoI coi), res) } + ; return (coToHsWrapper (mkSymCo coi), res) } -- The Sym is because the inner_match returns a coercion -- that is the other way round to matchExpectedPatTy | otherwise = do { (_, tys, subst) <- tcInstTyVars tvs ; wrap1 <- instCall PatOrigin tys (substTheta subst theta) - ; (wrap2, arg_tys) <- matchExpectedPatTy inner_match (substTy subst tau) + ; (wrap2, arg_tys) <- matchExpectedPatTy inner_match (TcType.substTy subst tau) ; return (wrap2 <.> wrap1 , arg_tys) } where (tvs, theta, tau) = tcSplitSigmaTy pat_ty @@ -749,7 +743,7 @@ matchExpectedPatTy inner_match pat_ty matchExpectedConTy :: TyCon -- The TyCon that this data -- constructor actually returns -> TcRhoType -- The type of the pattern - -> TcM (CoercionI, [TcSigmaType]) + -> TcM (Coercion, [TcSigmaType]) -- See Note [Matching constructor patterns] -- Returns a coercion : T ty1 ... tyn ~ pat_ty -- This is the same way round as matchExpectedListTy etc @@ -764,17 +758,16 @@ matchExpectedConTy data_tc pat_ty ; coi1 <- unifyType (mkTyConApp fam_tc (substTys subst fam_args)) pat_ty -- coi1 : T (ty1,ty2) ~ pat_ty - ; let coi2 = ACo (mkTyConApp co_tc tys) + ; let coi2 = mkAxInstCo co_tc tys -- coi2 : T (ty1,ty2) ~ T7 ty1 ty2 - ; return (mkTransCoI (mkSymCoI coi2) coi1, tys) } + ; return (mkTransCo (mkSymCo coi2) coi1, tys) } | otherwise = matchExpectedTyConApp data_tc pat_ty -- coi : T tys ~ pat_ty \end{code} -Noate [ Note [Matching constructor patterns] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Suppose (coi, tys) = matchExpectedConType data_tc pat_ty @@ -1006,12 +999,18 @@ sigPatCtxt pats bound_tvs pat_tys body_ty tidy_env -} \begin{code} -patCtxt :: Pat Name -> Maybe Message -- Not all patterns are worth pushing a context -patCtxt (VarPat _) = Nothing -patCtxt (ParPat _) = Nothing -patCtxt (AsPat _ _) = Nothing -patCtxt pat = Just (hang (ptext (sLit "In the pattern:")) - 2 (ppr pat)) +maybeWrapPatCtxt :: Pat Name -> (TcM a -> TcM b) -> TcM a -> TcM b +-- Not all patterns are worth pushing a context +maybeWrapPatCtxt pat tcm thing_inside + | not (worth_wrapping pat) = tcm thing_inside + | otherwise = addErrCtxt msg $ tcm $ popErrCtxt thing_inside + -- Remember to pop before doing thing_inside + where + worth_wrapping (VarPat {}) = False + worth_wrapping (ParPat {}) = False + worth_wrapping (AsPat {}) = False + worth_wrapping _ = True + msg = hang (ptext (sLit "In the pattern:")) 2 (ppr pat) ----------------------------------------------- checkExistentials :: [TyVar] -> PatEnv -> TcM () @@ -1047,9 +1046,6 @@ polyPatSig sig_ty = hang (ptext (sLit "Illegal polymorphic type signature in pattern:")) 2 (ppr sig_ty) -badTypePat :: Pat Name -> SDoc -badTypePat pat = ptext (sLit "Illegal type pattern") <+> ppr pat - lazyUnliftedPatErr :: OutputableBndr name => Pat name -> TcM () lazyUnliftedPatErr pat = failWithTc $