X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Fcompiler%2Ftypecheck%2FTcExpr.lhs;h=7b53c42f89aedccb02913cf1d645d57237d75ccf;hb=dfe408f871469d9ad057228149cc66c38299f0c9;hp=d3860c7e9f63582ddf8140b47b481c8d4f0f11e3;hpb=26741ec416bae2c502ef00a2ba0e79050a32cb67;p=ghc-hetmet.git diff --git a/ghc/compiler/typecheck/TcExpr.lhs b/ghc/compiler/typecheck/TcExpr.lhs index d3860c7..7b53c42 100644 --- a/ghc/compiler/typecheck/TcExpr.lhs +++ b/ghc/compiler/typecheck/TcExpr.lhs @@ -6,73 +6,78 @@ \begin{code} #include "HsVersions.h" -module TcExpr ( tcExpr ) where +module TcExpr ( tcExpr, tcStmt, tcId ) where IMP_Ubiq() -import HsSyn ( HsExpr(..), Qualifier(..), Stmt(..), - HsBinds(..), Bind(..), MonoBinds(..), +import HsSyn ( HsExpr(..), Stmt(..), DoOrListComp(..), + HsBinds(..), MonoBinds(..), + SYN_IE(RecFlag), nonRecursive, ArithSeqInfo(..), HsLit(..), Sig, GRHSsAndBinds, - Match, Fake, InPat, OutPat, PolyType, - failureFreePat, collectPatBinders ) -import RnHsSyn ( RenamedHsExpr(..), RenamedQual(..), - RenamedStmt(..), RenamedRecordBinds(..), - RnName{-instance Outputable-} + Match, Fake, InPat, OutPat, HsType, Fixity, + pprParendExpr, failureFreePat, collectPatBinders ) +import RnHsSyn ( SYN_IE(RenamedHsExpr), + SYN_IE(RenamedStmt), SYN_IE(RenamedRecordBinds) ) -import TcHsSyn ( TcExpr(..), TcQual(..), TcStmt(..), - TcIdOcc(..), TcRecordBinds(..), +import TcHsSyn ( SYN_IE(TcExpr), SYN_IE(TcStmt), + TcIdOcc(..), SYN_IE(TcRecordBinds), mkHsTyApp ) -import TcMonad hiding ( rnMtoTcM ) +import TcMonad import Inst ( Inst, InstOrigin(..), OverloadedLit(..), - LIE(..), emptyLIE, plusLIE, plusLIEs, newOverloadedLit, + SYN_IE(LIE), emptyLIE, plusLIE, plusLIEs, newOverloadedLit, newMethod, newMethodWithGivenTy, newDicts ) -import TcBinds ( tcBindsAndThen ) +import TcBinds ( tcBindsAndThen, checkSigTyVars ) import TcEnv ( tcLookupLocalValue, tcLookupGlobalValue, tcLookupClassByKey, tcLookupGlobalValueByKey, newMonoIds, tcGetGlobalTyVars, - tcExtendGlobalTyVars + tcExtendGlobalTyVars, tcLookupGlobalValueMaybe ) +import SpecEnv ( SpecEnv ) import TcMatches ( tcMatchesCase, tcMatch ) -import TcMonoType ( tcPolyType ) +import TcMonoType ( tcHsType ) import TcPat ( tcPat ) import TcSimplify ( tcSimplifyAndCheck, tcSimplifyRank2 ) -import TcType ( TcType(..), TcMaybe(..), - tcInstId, tcInstType, tcInstSigTcType, - tcInstSigType, tcInstTcType, tcInstTheta, - newTyVarTy, zonkTcTyVars, zonkTcType ) +import TcType ( SYN_IE(TcType), TcMaybe(..), + tcInstId, tcInstType, tcInstSigTcType, tcInstTyVars, + tcInstSigType, tcInstTcType, tcInstTheta, tcSplitRhoTy, + newTyVarTy, newTyVarTys, zonkTcTyVars, zonkTcType ) import TcKind ( TcKind ) import Class ( SYN_IE(Class), classSig ) -import FieldLabel ( fieldLabelName ) -import Id ( idType, dataConFieldLabels, dataConSig, SYN_IE(Id), GenId ) +import FieldLabel ( fieldLabelName, fieldLabelType ) +import Id ( idType, dataConFieldLabels, dataConSig, recordSelectorFieldLabel, + isRecordSelector, + SYN_IE(Id), GenId + ) +import FieldLabel ( FieldLabel ) import Kind ( Kind, mkBoxedTypeKind, mkTypeKind, mkArrowKind ) -import GenSpecEtc ( checkSigTyVars ) import Name ( Name{-instance Eq-} ) import Type ( mkFunTy, mkAppTy, mkTyVarTy, mkTyVarTys, mkRhoTy, - getTyVar_maybe, getFunTy_maybe, instantiateTy, + getTyVar_maybe, getFunTy_maybe, instantiateTy, applyTyCon, splitForAllTy, splitRhoTy, splitSigmaTy, splitFunTy, - isTauTy, mkFunTys, tyVarsOfType, getForAllTy_maybe, + isTauTy, mkFunTys, tyVarsOfType, tyVarsOfTypes, getForAllTy_maybe, getAppDataTyCon, maybeAppDataTyCon ) -import TyVar ( GenTyVar, SYN_IE(TyVarSet), unionTyVarSets, mkTyVarSet ) +import TyVar ( GenTyVar, SYN_IE(TyVarSet), unionTyVarSets, elementOfTyVarSet, mkTyVarSet ) import TysPrim ( intPrimTy, charPrimTy, doublePrimTy, - floatPrimTy, addrPrimTy + floatPrimTy, addrPrimTy, realWorldTy ) import TysWiredIn ( addrTy, boolTy, charTy, stringTy, mkListTy, - mkTupleTy, mkPrimIoTy, primIoDataCon + mkTupleTy, mkPrimIoTy, stDataCon ) import Unify ( unifyTauTy, unifyTauTyList, unifyTauTyLists, unifyFunTy ) import Unique ( Unique, cCallableClassKey, cReturnableClassKey, enumFromClassOpKey, enumFromThenClassOpKey, enumFromToClassOpKey, enumFromThenToClassOpKey, - thenMClassOpKey, zeroClassOpKey + thenMClassOpKey, zeroClassOpKey, returnMClassOpKey ) -import Outputable ( interpp'SP ) +import Outputable ( speakNth, interpp'SP, Outputable(..) ) import PprType ( GenType, GenTyVar ) -- Instances import Maybes ( maybeToBool ) import Pretty +import ListSetOps ( minusList ) import Util \end{code} @@ -187,9 +192,9 @@ tcExpr (HsApp e1 e2) = accum e1 [e2] returnTc (foldl HsApp fun' args', lie, res_ty) -- equivalent to (op e1) e2: -tcExpr (OpApp arg1 op arg2) +tcExpr (OpApp arg1 op fix arg2) = tcApp op [arg1,arg2] `thenTc` \ (op', [arg1', arg2'], lie, res_ty) -> - returnTc (OpApp arg1' op' arg2', lie, res_ty) + returnTc (OpApp arg1' op' fix arg2', lie, res_ty) \end{code} Note that the operators in sections are expected to be binary, and @@ -229,7 +234,7 @@ tcExpr in_expr@(SectionR op expr) newTyVarTy mkTypeKind `thenNF_Tc` \ ty1 -> newTyVarTy mkTypeKind `thenNF_Tc` \ ty2 -> tcAddErrCtxt (sectionRAppCtxt in_expr) $ - unifyTauTy op_ty (mkFunTys [ty1, expr_ty] ty2) `thenTc_` + unifyTauTy (mkFunTys [ty1, expr_ty] ty2) op_ty `thenTc_` returnTc (SectionR op' expr', lie1 `plusLIE` lie2, mkFunTy ty1 ty2) \end{code} @@ -269,8 +274,9 @@ tcExpr (CCall lbl args may_gc is_asm ignored_fake_result_ty) mapNF_Tc new_arg_dict (zipEqual "tcExpr:CCall" args arg_tys) `thenNF_Tc` \ ccarg_dicts_s -> newDicts result_origin [(cReturnableClass, result_ty)] `thenNF_Tc` \ (ccres_dict, _) -> - returnTc (HsCon primIoDataCon [result_ty] [CCall lbl args' may_gc is_asm result_ty], - -- do the wrapping in the newtype constructor here + returnTc (HsApp (HsVar (RealId stDataCon) `TyApp` [realWorldTy, result_ty]) + (CCall lbl args' may_gc is_asm result_ty), + -- do the wrapping in the newtype constructor here foldr plusLIE ccres_dict ccarg_dicts_s `plusLIE` args_lie, mkPrimIoTy result_ty) \end{code} @@ -283,9 +289,14 @@ tcExpr (HsSCC label expr) tcExpr (HsLet binds expr) = tcBindsAndThen - HsLet -- The combiner + combiner binds -- Bindings to check - (tcExpr expr) -- Typechecker for the expression + (tc_expr expr) `thenTc` \ ((expr', ty), lie) -> + returnTc (expr', lie, ty) + where + tc_expr expr = tcExpr expr `thenTc` \ (expr', lie, ty) -> + returnTc ((expr',ty), lie) + combiner bind (expr, ty) = (HsLet bind expr, ty) tcExpr in_expr@(HsCase expr matches src_loc) = tcAddSrcLoc src_loc $ @@ -303,7 +314,7 @@ tcExpr (HsIf pred b1 b2 src_loc) tcExpr pred `thenTc` \ (pred',lie1,predTy) -> tcAddErrCtxt (predCtxt pred) ( - unifyTauTy predTy boolTy + unifyTauTy boolTy predTy ) `thenTc_` tcExpr b1 `thenTc` \ (b1',lie2,result_ty) -> @@ -313,15 +324,11 @@ tcExpr (HsIf pred b1 b2 src_loc) unifyTauTy result_ty b2Ty `thenTc_` returnTc (HsIf pred' b1' b2' src_loc, plusLIE lie1 (plusLIE lie2 lie3), result_ty) - -tcExpr (ListComp expr quals) - = tcListComp expr quals `thenTc` \ ((expr',quals'), lie, ty) -> - returnTc (ListComp expr' quals', lie, ty) \end{code} \begin{code} -tcExpr expr@(HsDo stmts src_loc) - = tcDoStmts stmts src_loc +tcExpr expr@(HsDo do_or_lc stmts src_loc) + = tcDoStmts do_or_lc stmts src_loc \end{code} \begin{code} @@ -348,48 +355,134 @@ tcExpr (RecordCon (HsVar con) rbinds) -- Con is syntactically constrained to be a data constructor ASSERT( maybeToBool (maybeAppDataTyCon record_ty ) ) - tcRecordBinds record_ty rbinds `thenTc` \ (rbinds', rbinds_lie) -> - -- Check that the record bindings match the constructor - tcLookupGlobalValue con `thenNF_Tc` \ con_id -> - checkTc (checkRecordFields rbinds con_id) - (badFieldsCon con rbinds) `thenTc_` + tcLookupGlobalValue con `thenNF_Tc` \ con_id -> + let + bad_fields = badFields rbinds con_id + in + checkTc (null bad_fields) (badFieldsCon con bad_fields) `thenTc_` + + -- Typecheck the record bindings + -- (Do this after checkRecordFields in case there's a field that + -- doesn't match the constructor.) + tcRecordBinds record_ty rbinds `thenTc` \ (rbinds', rbinds_lie) -> returnTc (RecordCon con_expr rbinds', con_lie `plusLIE` rbinds_lie, record_ty) --- One small complication in RecordUpd is that we have to generate some --- dictionaries for the data type context, since we are going to --- do some construction. + +-- The main complication with RecordUpd is that we need to explicitly +-- handle the *non-updated* fields. Consider: +-- +-- data T a b = MkT1 { fa :: a, fb :: b } +-- | MkT2 { fa :: a, fc :: Int -> Int } +-- | MkT3 { fd :: a } +-- +-- upd :: T a b -> c -> T a c +-- upd t x = t { fb = x} +-- +-- The type signature on upd is correct (i.e. the result should not be (T a b)) +-- because upd should be equivalent to: -- --- What dictionaries do we need? For the moment we assume that all --- data constructors have the same context, and grab it from the first --- constructor. If they have varying contexts then we'd have to --- union the ones that could participate in the update. +-- upd t x = case t of +-- MkT1 p q -> MkT1 p x +-- MkT2 a b -> MkT2 p b +-- MkT3 d -> error ... +-- +-- So we need to give a completely fresh type to the result record, +-- and then constrain it by the fields that are *not* updated ("p" above). +-- +-- Note that because MkT3 doesn't contain all the fields being updated, +-- its RHS is simply an error, so it doesn't impose any type constraints +-- +-- All this is done in STEP 4 below. tcExpr (RecordUpd record_expr rbinds) - = ASSERT( not (null rbinds) ) - tcAddErrCtxt recordUpdCtxt $ - - tcExpr record_expr `thenTc` \ (record_expr', record_lie, record_ty) -> - tcRecordBinds record_ty rbinds `thenTc` \ (rbinds', rbinds_lie) -> + = tcAddErrCtxt recordUpdCtxt $ - -- Check that the field names are plausible - zonkTcType record_ty `thenNF_Tc` \ record_ty' -> + -- STEP 1 + -- Figure out the tycon and data cons from the first field name + ASSERT( not (null rbinds) ) + let + ((first_field_name, _, _) : rest) = rbinds + in + tcLookupGlobalValueMaybe first_field_name `thenNF_Tc` \ maybe_sel_id -> + (case maybe_sel_id of + Just sel_id | isRecordSelector sel_id -> returnTc sel_id + other -> failTc (notSelector first_field_name) + ) `thenTc` \ sel_id -> let - (tycon, inst_tys, data_cons) = trace "TcExpr.getAppDataTyCon" $ getAppDataTyCon record_ty' - -- The record binds are non-empty (syntax); so at least one field - -- label will have been unified with record_ty by tcRecordBinds; - -- field labels must be of data type; hencd the getAppDataTyCon must succeed. - (tyvars, theta, _, _) = dataConSig (head data_cons) + (_, tau) = splitForAllTy (idType sel_id) + Just (data_ty, _) = getFunTy_maybe tau -- Must succeed since sel_id is a selector + (tycon, _, data_cons) = getAppDataTyCon data_ty + (con_tyvars, theta, _, _, _, _) = dataConSig (head data_cons) in - tcInstTheta (zipEqual "tcExpr:RecordUpd" tyvars inst_tys) theta `thenNF_Tc` \ theta' -> - newDicts RecordUpdOrigin theta' `thenNF_Tc` \ (con_lie, dicts) -> - checkTc (any (checkRecordFields rbinds) data_cons) + tcInstTyVars con_tyvars `thenNF_Tc` \ (_, result_inst_tys, result_inst_env) -> + + -- STEP 2 + -- Check for bad fields + checkTc (any (null . badFields rbinds) data_cons) (badFieldsUpd rbinds) `thenTc_` - returnTc (RecordUpdOut record_expr' dicts rbinds', + -- STEP 3 + -- Typecheck the update bindings. + -- (Do this after checking for bad fields in case there's a field that + -- doesn't match the constructor.) + let + result_record_ty = applyTyCon tycon result_inst_tys + in + tcRecordBinds result_record_ty rbinds `thenTc` \ (rbinds', rbinds_lie) -> + + -- STEP 4 + -- Use the un-updated fields to find a vector of booleans saying + -- which type arguments must be the same in updatee and result. + -- + -- WARNING: this code assumes that all data_cons in a common tycon + -- have FieldLabels abstracted over the same tyvars. + let + upd_field_lbls = [recordSelectorFieldLabel sel_id | (RealId sel_id, _, _) <- rbinds'] + con_field_lbls_s = map dataConFieldLabels data_cons + + -- A constructor is only relevant to this process if + -- it contains all the fields that are being updated + relevant_field_lbls_s = filter is_relevant con_field_lbls_s + is_relevant con_field_lbls = all (`elem` con_field_lbls) upd_field_lbls + + non_upd_field_lbls = concat relevant_field_lbls_s `minusList` upd_field_lbls + common_tyvars = tyVarsOfTypes (map fieldLabelType non_upd_field_lbls) + + mk_inst_ty (tyvar, result_inst_ty) + | tyvar `elementOfTyVarSet` common_tyvars = returnNF_Tc result_inst_ty -- Same as result type + | otherwise = newTyVarTy mkBoxedTypeKind -- Fresh type + in + mapNF_Tc mk_inst_ty (zip con_tyvars result_inst_tys) `thenNF_Tc` \ inst_tys -> + + -- STEP 5 + -- Typecheck the expression to be updated + tcExpr record_expr `thenTc` \ (record_expr', record_lie, record_ty) -> + unifyTauTy (applyTyCon tycon inst_tys) record_ty `thenTc_` + + + -- STEP 6 + -- Figure out the LIE we need. We have to generate some + -- dictionaries for the data type context, since we are going to + -- do some construction. + -- + -- What dictionaries do we need? For the moment we assume that all + -- data constructors have the same context, and grab it from the first + -- constructor. If they have varying contexts then we'd have to + -- union the ones that could participate in the update. + let + (tyvars, theta, _, _, _, _) = dataConSig (head data_cons) + inst_env = zipEqual "tcExpr:RecordUpd" tyvars result_inst_tys + in + tcInstTheta inst_env theta `thenNF_Tc` \ theta' -> + newDicts RecordUpdOrigin theta' `thenNF_Tc` \ (con_lie, dicts) -> + + -- Phew! + returnTc (RecordUpdOut record_expr' result_record_ty dicts rbinds', con_lie `plusLIE` record_lie `plusLIE` rbinds_lie, - record_ty) + result_record_ty) + tcExpr (ArithSeqIn seq@(From expr)) = tcExpr expr `thenTc` \ (expr', lie1, ty) -> @@ -461,7 +554,7 @@ tcExpr in_expr@(ArithSeqIn seq@(FromThenTo expr1 expr2 expr3)) \begin{code} tcExpr in_expr@(ExprWithTySig expr poly_ty) = tcExpr expr `thenTc` \ (texpr, lie, tau_ty) -> - tcPolyType poly_ty `thenTc` \ sigma_sig -> + tcHsType poly_ty `thenTc` \ sigma_sig -> -- Check the tau-type part tcSetErrCtxt (exprSigCtxt in_expr) $ @@ -469,7 +562,7 @@ tcExpr in_expr@(ExprWithTySig expr poly_ty) let (sig_tyvars', sig_theta', sig_tau') = splitSigmaTy sigma_sig' in - unifyTauTy tau_ty sig_tau' `thenTc_` + unifyTauTy sig_tau' tau_ty `thenTc_` -- Check the type variables of the signature checkSigTyVars sig_tyvars' sig_tau' `thenTc_` @@ -611,11 +704,7 @@ tcArg expected_arg_ty arg returnTc (TyLam sig_tyvars (HsLet (mk_binds inst_binds) arg'), free_insts) ) where - - mk_binds [] = EmptyBinds - mk_binds ((inst,rhs):inst_binds) - = (SingleBind (NonRecBind (VarMonoBind inst rhs))) `ThenBinds` - mk_binds inst_binds + mk_binds inst_binds = MonoBind inst_binds [] nonRecursive \end{code} %************************************************************************ @@ -625,7 +714,7 @@ tcArg expected_arg_ty arg %************************************************************************ \begin{code} -tcId :: RnName -> NF_TcM s (TcExpr s, LIE s, TcType s) +tcId :: Name -> NF_TcM s (TcExpr s, LIE s, TcType s) tcId name = -- Look up the Id and instantiate its type @@ -653,161 +742,160 @@ tcId name instantiate_it2 tc_id_occ tyvars rho instantiate_it2 tc_id_occ tyvars rho - | null theta -- Is it overloaded? - = returnNF_Tc (mkHsTyApp (HsVar tc_id_occ) arg_tys, emptyLIE, tau) - - | otherwise -- Yes, it's overloaded - = newMethodWithGivenTy (OccurrenceOf tc_id_occ) + = tcSplitRhoTy rho `thenNF_Tc` \ (theta, tau) -> + if null theta then -- Is it overloaded? + returnNF_Tc (mkHsTyApp (HsVar tc_id_occ) arg_tys, emptyLIE, tau) + else + -- Yes, it's overloaded + newMethodWithGivenTy (OccurrenceOf tc_id_occ) tc_id_occ arg_tys rho `thenNF_Tc` \ (lie1, meth_id) -> instantiate_it meth_id tau `thenNF_Tc` \ (expr, lie2, final_tau) -> returnNF_Tc (expr, lie1 `plusLIE` lie2, final_tau) where - (theta, tau) = splitRhoTy rho arg_tys = mkTyVarTys tyvars \end{code} %************************************************************************ %* * -\subsection{@tcQuals@ typechecks list-comprehension qualifiers} -%* * -%************************************************************************ - -\begin{code} -tcListComp expr [] - = tcExpr expr `thenTc` \ (expr', lie, ty) -> - returnTc ((expr',[]), lie, mkListTy ty) - -tcListComp expr (qual@(FilterQual filter) : quals) - = tcAddErrCtxt (qualCtxt qual) ( - tcExpr filter `thenTc` \ (filter', filter_lie, filter_ty) -> - unifyTauTy boolTy filter_ty `thenTc_` - returnTc (FilterQual filter', filter_lie) - ) `thenTc` \ (qual', qual_lie) -> - - tcListComp expr quals `thenTc` \ ((expr',quals'), rest_lie, res_ty) -> - - returnTc ((expr', qual' : quals'), - qual_lie `plusLIE` rest_lie, - res_ty) - -tcListComp expr (qual@(GeneratorQual pat rhs) : quals) - = newMonoIds binder_names mkBoxedTypeKind (\ ids -> - - tcAddErrCtxt (qualCtxt qual) ( - tcPat pat `thenTc` \ (pat', lie_pat, pat_ty) -> - tcExpr rhs `thenTc` \ (rhs', lie_rhs, rhs_ty) -> - -- NB: the environment has been extended with the new binders - -- which the rhs can't "see", but the renamer should have made - -- sure that everything is distinct by now, so there's no problem. - -- Putting the tcExpr before the newMonoIds messes up the nesting - -- of error contexts, so I didn't bother - - unifyTauTy (mkListTy pat_ty) rhs_ty `thenTc_` - returnTc (GeneratorQual pat' rhs', - lie_pat `plusLIE` lie_rhs) - ) `thenTc` \ (qual', lie_qual) -> - - tcListComp expr quals `thenTc` \ ((expr',quals'), lie_rest, res_ty) -> - - returnTc ((expr', qual' : quals'), - lie_qual `plusLIE` lie_rest, - res_ty) - ) - where - binder_names = collectPatBinders pat - -tcListComp expr (LetQual binds : quals) - = tcBindsAndThen -- No error context, but a binding group is - combine -- rather a large thing for an error context anyway - binds - (tcListComp expr quals) - where - combine binds' (expr',quals') = (expr', LetQual binds' : quals') -\end{code} - - -%************************************************************************ -%* * \subsection{@tcDoStmts@ typechecks a {\em list} of do statements} %* * %************************************************************************ \begin{code} -tcDoStmts stmts src_loc +tcDoStmts do_or_lc stmts src_loc = -- get the Monad and MonadZero classes -- create type consisting of a fresh monad tyvar + ASSERT( not (null stmts) ) tcAddSrcLoc src_loc $ newTyVarTy (mkArrowKind mkBoxedTypeKind mkBoxedTypeKind) `thenNF_Tc` \ m -> + let + tc_stmts [] = returnTc (([], error "tc_stmts"), emptyLIE) + tc_stmts (stmt:stmts) = tcStmt tcExpr do_or_lc (mkAppTy m) combine_stmts stmt $ + tc_stmts stmts + + combine_stmts stmt@(ReturnStmt _) (Just ty) ([], _) = ([stmt], ty) + combine_stmts stmt@(ExprStmt e _) (Just ty) ([], _) = ([stmt], ty) + combine_stmts stmt _ ([], _) = panic "Bad last stmt tcDoStmts" + combine_stmts stmt _ (stmts, ty) = (stmt:stmts, ty) + in + tc_stmts stmts `thenTc` \ ((stmts', result_ty), final_lie) -> -- Build the then and zero methods in case we need them + -- It's important that "then" and "return" appear just once in the final LIE, + -- not only for typechecker efficiency, but also because otherwise during + -- simplification we end up with silly stuff like + -- then = case d of (t,r) -> t + -- then = then + -- where the second "then" sees that it already exists in the "available" stuff. + -- + tcLookupGlobalValueByKey returnMClassOpKey `thenNF_Tc` \ return_sel_id -> tcLookupGlobalValueByKey thenMClassOpKey `thenNF_Tc` \ then_sel_id -> tcLookupGlobalValueByKey zeroClassOpKey `thenNF_Tc` \ zero_sel_id -> newMethod DoOrigin - (RealId then_sel_id) [m] `thenNF_Tc` \ (m_lie, then_id) -> + (RealId return_sel_id) [m] `thenNF_Tc` \ (return_lie, return_id) -> newMethod DoOrigin - (RealId zero_sel_id) [m] `thenNF_Tc` \ (mz_lie, zero_id) -> - + (RealId then_sel_id) [m] `thenNF_Tc` \ (then_lie, then_id) -> + newMethod DoOrigin + (RealId zero_sel_id) [m] `thenNF_Tc` \ (zero_lie, zero_id) -> let - get_m_arg ty - = newTyVarTy mkTypeKind `thenNF_Tc` \ arg_ty -> - unifyTauTy (mkAppTy m arg_ty) ty `thenTc_` - returnTc arg_ty - - go [stmt@(ExprStmt exp src_loc)] - = tcAddSrcLoc src_loc $ - tcSetErrCtxt (stmtCtxt stmt) $ - tcExpr exp `thenTc` \ (exp', exp_lie, exp_ty) -> - returnTc ([ExprStmt exp' src_loc], exp_lie, exp_ty) - - go (stmt@(ExprStmt exp src_loc) : stmts) - = tcAddSrcLoc src_loc ( - tcSetErrCtxt (stmtCtxt stmt) ( - tcExpr exp `thenTc` \ (exp', exp_lie, exp_ty) -> - get_m_arg exp_ty `thenTc` \ a -> - returnTc (a, exp', exp_lie) - )) `thenTc` \ (a, exp', exp_lie) -> - go stmts `thenTc` \ (stmts', stmts_lie, stmts_ty) -> - get_m_arg stmts_ty `thenTc` \ b -> - returnTc (ExprStmtOut exp' src_loc a b : stmts', - exp_lie `plusLIE` stmts_lie `plusLIE` m_lie, - stmts_ty) - - go (stmt@(BindStmt pat exp src_loc) : stmts) - = newMonoIds (collectPatBinders pat) mkBoxedTypeKind $ \ _ -> - tcAddSrcLoc src_loc ( - tcSetErrCtxt (stmtCtxt stmt) ( - tcPat pat `thenTc` \ (pat', pat_lie, pat_ty) -> - tcExpr exp `thenTc` \ (exp', exp_lie, exp_ty) -> - -- See comments with tcListComp on GeneratorQual - - get_m_arg exp_ty `thenTc` \ a -> - unifyTauTy a pat_ty `thenTc_` - returnTc (a, pat', exp', pat_lie `plusLIE` exp_lie) - )) `thenTc` \ (a, pat', exp', stmt_lie) -> - go stmts `thenTc` \ (stmts', stmts_lie, stmts_ty) -> - get_m_arg stmts_ty `thenTc` \ b -> - returnTc (BindStmtOut pat' exp' src_loc a b : stmts', - stmt_lie `plusLIE` stmts_lie `plusLIE` m_lie `plusLIE` - (if failureFreePat pat' then emptyLIE else mz_lie), - stmts_ty) - - go (LetStmt binds : stmts) - = tcBindsAndThen -- No error context, but a binding group is - combine -- rather a large thing for an error context anyway - binds - (go stmts) - where - combine binds' stmts' = LetStmt binds' : stmts' + monad_lie = then_lie `plusLIE` return_lie `plusLIE` perhaps_zero_lie + perhaps_zero_lie | all failure_free stmts' = emptyLIE + | otherwise = zero_lie + + failure_free (BindStmt pat _ _) = failureFreePat pat + failure_free (GuardStmt _ _) = False + failure_free other_stmt = True in + returnTc (HsDoOut do_or_lc stmts' return_id then_id zero_id result_ty src_loc, + final_lie `plusLIE` monad_lie, + result_ty) +\end{code} - go stmts `thenTc` \ (stmts', final_lie, final_ty) -> - returnTc (HsDoOut stmts' then_id zero_id src_loc, - final_lie, - final_ty) +\begin{code} +tcStmt :: (RenamedHsExpr -> TcM s (TcExpr s, LIE s, TcType s)) -- This is tcExpr + -- The sole, disgusting, reason for this parameter + -- is to get the effect of polymorphic recursion + -- ToDo: rm when booting with Haskell 1.3 + -> DoOrListComp + -> (TcType s -> TcType s) -- Relationship type of pat and rhs in pat <- rhs + -> (TcStmt s -> Maybe (TcType s) -> thing -> thing) + -> RenamedStmt + -> TcM s (thing, LIE s) + -> TcM s (thing, LIE s) + +tcStmt tc_expr do_or_lc m combine stmt@(ReturnStmt exp) do_next + = ASSERT( case do_or_lc of { DoStmt -> False; ListComp -> True } ) + tcSetErrCtxt (stmtCtxt do_or_lc stmt) ( + tc_expr exp `thenTc` \ (exp', exp_lie, exp_ty) -> + returnTc (ReturnStmt exp', exp_lie, m exp_ty) + ) `thenTc` \ (stmt', stmt_lie, stmt_ty) -> + do_next `thenTc` \ (thing', thing_lie) -> + returnTc (combine stmt' (Just stmt_ty) thing', + stmt_lie `plusLIE` thing_lie) + +tcStmt tc_expr do_or_lc m combine stmt@(GuardStmt exp src_loc) do_next + = ASSERT( case do_or_lc of { DoStmt -> False; ListComp -> True } ) + tcAddSrcLoc src_loc ( + tcSetErrCtxt (stmtCtxt do_or_lc stmt) ( + tc_expr exp `thenTc` \ (exp', exp_lie, exp_ty) -> + unifyTauTy boolTy exp_ty `thenTc_` + returnTc (GuardStmt exp' src_loc, exp_lie) + )) `thenTc` \ (stmt', stmt_lie) -> + do_next `thenTc` \ (thing', thing_lie) -> + returnTc (combine stmt' Nothing thing', + stmt_lie `plusLIE` thing_lie) + +tcStmt tc_expr do_or_lc m combine stmt@(ExprStmt exp src_loc) do_next + = ASSERT( case do_or_lc of { DoStmt -> True; ListComp -> False } ) + tcAddSrcLoc src_loc ( + tcSetErrCtxt (stmtCtxt do_or_lc stmt) ( + tc_expr exp `thenTc` \ (exp', exp_lie, exp_ty) -> + -- Check that exp has type (m tau) for some tau (doesn't matter what) + newTyVarTy mkTypeKind `thenNF_Tc` \ tau -> + unifyTauTy (m tau) exp_ty `thenTc_` + returnTc (ExprStmt exp' src_loc, exp_lie, exp_ty) + )) `thenTc` \ (stmt', stmt_lie, stmt_ty) -> + do_next `thenTc` \ (thing', thing_lie) -> + returnTc (combine stmt' (Just stmt_ty) thing', + stmt_lie `plusLIE` thing_lie) + +tcStmt tc_expr do_or_lc m combine stmt@(BindStmt pat exp src_loc) do_next + = newMonoIds (collectPatBinders pat) mkBoxedTypeKind $ \ _ -> + tcAddSrcLoc src_loc ( + tcSetErrCtxt (stmtCtxt do_or_lc stmt) ( + tcPat pat `thenTc` \ (pat', pat_lie, pat_ty) -> + tc_expr exp `thenTc` \ (exp', exp_lie, exp_ty) -> + unifyTauTy (m pat_ty) exp_ty `thenTc_` + + -- NB: the environment has been extended with the new binders + -- which the rhs can't "see", but the renamer should have made + -- sure that everything is distinct by now, so there's no problem. + -- Putting the tcExpr before the newMonoIds messes up the nesting + -- of error contexts, so I didn't bother + + returnTc (BindStmt pat' exp' src_loc, pat_lie `plusLIE` exp_lie) + )) `thenTc` \ (stmt', stmt_lie) -> + do_next `thenTc` \ (thing', thing_lie) -> + returnTc (combine stmt' Nothing thing', + stmt_lie `plusLIE` thing_lie) + +tcStmt tc_expr do_or_lc m combine (LetStmt binds) do_next + = tcBindsAndThen -- No error context, but a binding group is + combine' -- rather a large thing for an error context anyway + binds + do_next + where + combine' binds' thing' = combine (LetStmt binds') Nothing thing' \end{code} +%************************************************************************ +%* * +\subsection{Record bindings} +%* * +%************************************************************************ + Game plan for record bindings ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ For each binding @@ -842,6 +930,11 @@ tcRecordBinds expected_record_ty rbinds where do_bind (field_label, rhs, pun_flag) = tcLookupGlobalValue field_label `thenNF_Tc` \ sel_id -> + ASSERT( isRecordSelector sel_id ) + -- This lookup and assertion will surely succeed, because + -- we check that the fields are indeed record selectors + -- before calling tcRecordBinds + tcInstId sel_id `thenNF_Tc` \ (_, _, tau) -> -- Record selectors all have type @@ -855,17 +948,12 @@ tcRecordBinds expected_record_ty rbinds tcArg field_ty rhs `thenTc` \ (rhs', lie) -> returnTc ((RealId sel_id, rhs', pun_flag), lie) -checkRecordFields :: RenamedRecordBinds -> Id -> Bool -- True iff all the fields in - -- RecordBinds are field of the - -- specified constructor -checkRecordFields rbinds data_con - = all ok rbinds - where - data_con_fields = dataConFieldLabels data_con - - ok (field_name, _, _) = any (match (getName field_name)) data_con_fields - - match field_name field_label = field_name == fieldLabelName field_label +badFields rbinds data_con + = [field_name | (field_name, _, _) <- rbinds, + not (field_name `elem` field_names) + ] + where + field_names = map fieldLabelName (dataConFieldLabels data_con) \end{code} %************************************************************************ @@ -892,76 +980,78 @@ Errors and contexts Mini-utils: \begin{code} -pp_nest_hang :: String -> Pretty -> Pretty -pp_nest_hang label stuff = ppNest 2 (ppHang (ppStr label) 4 stuff) +pp_nest_hang :: String -> Doc -> Doc +pp_nest_hang label stuff = nest 2 (hang (text label) 4 stuff) \end{code} Boring and alphabetical: \begin{code} arithSeqCtxt expr sty - = ppHang (ppStr "In an arithmetic sequence:") 4 (ppr sty expr) + = hang (ptext SLIT("In an arithmetic sequence:")) 4 (ppr sty expr) branchCtxt b1 b2 sty - = ppSep [ppStr "In the branches of a conditional:", + = sep [ptext SLIT("In the branches of a conditional:"), pp_nest_hang "`then' branch:" (ppr sty b1), pp_nest_hang "`else' branch:" (ppr sty b2)] caseCtxt expr sty - = ppHang (ppStr "In a case expression:") 4 (ppr sty expr) + = hang (ptext SLIT("In a case expression:")) 4 (ppr sty expr) exprSigCtxt expr sty - = ppHang (ppStr "In an expression with a type signature:") + = hang (ptext SLIT("In an expression with a type signature:")) 4 (ppr sty expr) listCtxt expr sty - = ppHang (ppStr "In a list expression:") 4 (ppr sty expr) + = hang (ptext SLIT("In a list expression:")) 4 (ppr sty expr) predCtxt expr sty - = ppHang (ppStr "In a predicate expression:") 4 (ppr sty expr) + = hang (ptext SLIT("In a predicate expression:")) 4 (ppr sty expr) sectionRAppCtxt expr sty - = ppHang (ppStr "In a right section:") 4 (ppr sty expr) + = hang (ptext SLIT("In a right section:")) 4 (ppr sty expr) sectionLAppCtxt expr sty - = ppHang (ppStr "In a left section:") 4 (ppr sty expr) + = hang (ptext SLIT("In a left section:")) 4 (ppr sty expr) funAppCtxt fun arg_no arg sty - = ppHang (ppCat [ ppStr "In the", speakNth arg_no, ppStr "argument of", ppr sty fun]) - 4 (ppCat [ppStr "namely", ppr sty arg]) + = hang (hsep [ ptext SLIT("In the"), speakNth arg_no, ptext SLIT("argument of"), + ppr sty fun <> text ", namely"]) + 4 (pprParendExpr sty arg) -qualCtxt qual sty - = ppHang (ppStr "In a list-comprehension qualifer:") - 4 (ppr sty qual) +stmtCtxt ListComp stmt sty + = hang (ptext SLIT("In a list-comprehension qualifer:")) + 4 (ppr sty stmt) -stmtCtxt stmt sty - = ppHang (ppStr "In a do statement:") +stmtCtxt DoStmt stmt sty + = hang (ptext SLIT("In a do statement:")) 4 (ppr sty stmt) tooManyArgsCtxt f sty - = ppHang (ppStr "Too many arguments in an application of the function") + = hang (ptext SLIT("Too many arguments in an application of the function")) 4 (ppr sty f) lurkingRank2Err fun fun_ty sty - = ppHang (ppCat [ppStr "Illegal use of", ppr sty fun]) - 4 (ppAboves [ppStr "It is applied to too few arguments,", - ppStr "so that the result type has for-alls in it"]) + = hang (hsep [ptext SLIT("Illegal use of"), ppr sty fun]) + 4 (vcat [text "It is applied to too few arguments,", + ptext SLIT("so that the result type has for-alls in it")]) rank2ArgCtxt arg expected_arg_ty sty - = ppHang (ppStr "In a polymorphic function argument:") - 4 (ppSep [ppBeside (ppr sty arg) (ppStr " ::"), + = hang (ptext SLIT("In a polymorphic function argument:")) + 4 (sep [(<>) (ppr sty arg) (ptext SLIT(" ::")), ppr sty expected_arg_ty]) badFieldsUpd rbinds sty - = ppHang (ppStr "No constructor has all these fields:") + = hang (ptext SLIT("No constructor has all these fields:")) 4 (interpp'SP sty fields) where fields = [field | (field, _, _) <- rbinds] -recordUpdCtxt sty = ppStr "In a record update construct" +recordUpdCtxt sty = ptext SLIT("In a record update construct") -badFieldsCon con rbinds sty - = ppHang (ppBesides [ppStr "Inconsistent constructor:", ppr sty con]) - 4 (ppBesides [ppStr "and fields:", interpp'SP sty fields]) - where - fields = [field | (field, _, _) <- rbinds] +badFieldsCon con fields sty + = hsep [ptext SLIT("Constructor"), ppr sty con, + ptext SLIT("does not have field(s)"), interpp'SP sty fields] + +notSelector field sty + = hsep [ppr sty field, ptext SLIT("is not a record selector")] \end{code}