X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Fcompiler%2Ftypecheck%2FTcExpr.lhs;h=cb57efdc2868e993e3f00978abc040d958eca901;hb=d75105426df54cf78cf5827ed307a64b51a0f428;hp=0e719a9e5ff247d4b47c7e031a242a8dfbdd195e;hpb=51d9f5df468fdc09ea97d116c71cd7b95fcfe0fe;p=ghc-hetmet.git diff --git a/ghc/compiler/typecheck/TcExpr.lhs b/ghc/compiler/typecheck/TcExpr.lhs index 0e719a9..cb57efd 100644 --- a/ghc/compiler/typecheck/TcExpr.lhs +++ b/ghc/compiler/typecheck/TcExpr.lhs @@ -1,83 +1,71 @@ % -% (c) The GRASP/AQUA Project, Glasgow University, 1992-1996 +% (c) The GRASP/AQUA Project, Glasgow University, 1992-1998 % \section[TcExpr]{Typecheck an expression} \begin{code} -module TcExpr ( tcExpr, tcId ) where +module TcExpr ( tcApp, tcExpr, tcMonoExpr, tcPolyExpr, tcId ) where #include "HsVersions.h" import HsSyn ( HsExpr(..), HsLit(..), ArithSeqInfo(..), - HsBinds(..), Stmt(..), DoOrListComp(..), - failureFreePat, collectPatBinders - ) -import RnHsSyn ( RenamedHsExpr, - RenamedStmt, RenamedRecordBinds - ) -import TcHsSyn ( TcExpr, TcStmt, - TcRecordBinds, - mkHsTyApp + HsMatchContext(..), HsDoContext(..), mkMonoBind ) +import RnHsSyn ( RenamedHsExpr, RenamedRecordBinds ) +import TcHsSyn ( TcExpr, TcRecordBinds, mkHsLet ) import TcMonad -import BasicTypes ( RecFlag(..) ) - -import Inst ( Inst, InstOrigin(..), OverloadedLit(..), - LIE, emptyLIE, plusLIE, plusLIEs, newOverloadedLit, - newMethod, newMethodWithGivenTy, newDicts ) -import TcBinds ( tcBindsAndThen, checkSigTyVars ) -import TcEnv ( TcIdOcc(..), tcInstId, - tcLookupLocalValue, tcLookupGlobalValue, tcLookupClassByKey, - tcLookupGlobalValueByKey, newMonoIds, - tcExtendGlobalTyVars, tcLookupGlobalValueMaybe, - tcLookupTyCon +import BasicTypes ( RecFlag(..), isMarkedStrict ) +import Inst ( InstOrigin(..), + LIE, mkLIE, emptyLIE, unitLIE, plusLIE, plusLIEs, + newOverloadedLit, newMethod, newIPDict, + newDicts, + instToId, tcInstId ) -import TcMatches ( tcMatchesCase, tcMatchExpected ) -import TcGRHSs ( tcStmt ) -import TcMonoType ( tcHsType ) -import TcPat ( tcPat ) -import TcSimplify ( tcSimplifyAndCheck ) -import TcType ( TcType, TcTauType, TcMaybe(..), - tcInstType, tcInstSigTcType, tcInstTyVars, - tcInstSigType, tcInstTcType, tcInstTheta, tcSplitRhoTy, - newTyVarTy, newTyVarTys, zonkTcType ) -import TcKind ( TcKind ) - -import Class ( Class ) -import FieldLabel ( FieldLabel, fieldLabelName, fieldLabelType ) -import Id ( idType, dataConFieldLabels, dataConSig, recordSelectorFieldLabel, - isRecordSelector, - Id +import TcBinds ( tcBindsAndThen ) +import TcEnv ( tcLookupClass, tcLookupGlobalId, tcLookupGlobal_maybe, + tcLookupTyCon, tcLookupDataCon, tcLookupId, + tcExtendGlobalTyVars ) -import Kind ( Kind, mkBoxedTypeKind, mkTypeKind, mkArrowKind ) -import Name ( Name{-instance Eq-} ) -import Type ( mkFunTy, mkAppTy, mkTyVarTy, mkTyVarTys, - splitFunTy_maybe, splitFunTys, - mkTyConApp, - splitForAllTys, splitRhoTy, splitSigmaTy, - isTauTy, tyVarsOfType, tyVarsOfTypes, - isForAllTy, splitAlgTyConApp, splitAlgTyConApp_maybe +import TcMatches ( tcMatchesCase, tcMatchLambda, tcStmts ) +import TcMonoType ( tcHsSigType, UserTypeCtxt(..), checkSigTyVars, sigCtxt ) +import TcPat ( badFieldCon, simpleHsLitTy ) +import TcSimplify ( tcSimplifyCheck, tcSimplifyIPs ) +import TcMType ( tcInstTyVars, tcInstType, + newTyVarTy, newTyVarTys, zonkTcType, + unifyTauTy, unifyFunTy, unifyListTy, unifyTupleTy ) -import TyVar ( emptyTyVarEnv, zipTyVarEnv, - elementOfTyVarSet, mkTyVarSet, tyVarSetToList +import TcType ( tcSplitFunTys, tcSplitTyConApp, + isQualifiedTy, + mkFunTy, mkAppTy, mkTyConTy, + mkTyConApp, mkClassPred, tcFunArgTy, + isTauTy, tyVarsOfType, tyVarsOfTypes, + liftedTypeKind, openTypeKind, mkArrowKind, + tcSplitSigmaTy, tcTyConAppTyCon, + tidyOpenType ) -import TyCon ( tyConDataCons ) -import TysPrim ( intPrimTy, charPrimTy, doublePrimTy, - floatPrimTy, addrPrimTy +import FieldLabel ( FieldLabel, fieldLabelName, fieldLabelType, fieldLabelTyCon ) +import Id ( idType, recordSelectorFieldLabel, isRecordSelector ) +import DataCon ( dataConFieldLabels, dataConSig, + dataConStrictMarks ) -import TysWiredIn ( boolTy, charTy, stringTy ) -import PrelInfo ( ioTyCon_NAME ) -import Unify ( unifyTauTy, unifyFunTy, unifyListTy, unifyTupleTy ) -import Unique ( Unique, cCallableClassKey, cReturnableClassKey, - enumFromClassOpKey, enumFromThenClassOpKey, - enumFromToClassOpKey, enumFromThenToClassOpKey, - thenMClassOpKey, zeroClassOpKey, returnMClassOpKey +import Name ( Name ) +import TyCon ( TyCon, tyConTyVars, isAlgTyCon, tyConDataCons ) +import Subst ( mkTopTyVarSubst, substTheta, substTy ) +import VarSet ( elemVarSet ) +import TysWiredIn ( boolTy, mkListTy, listTyCon ) +import PrelNames ( cCallableClassName, + cReturnableClassName, + enumFromName, enumFromThenName, + enumFromToName, enumFromThenToName, + thenMName, failMName, returnMName, ioTyConName ) import Outputable -import Maybes ( maybeToBool ) import ListSetOps ( minusList ) import Util +import CmdLineOpts +import HscTypes ( TyThing(..) ) + \end{code} %************************************************************************ @@ -87,16 +75,16 @@ import Util %************************************************************************ \begin{code} -tcExpr :: RenamedHsExpr -- Expession to type check - -> TcType s -- Expected type (could be a polytpye) - -> TcM s (TcExpr s, LIE s) +tcExpr :: RenamedHsExpr -- Expession to type check + -> TcType -- Expected type (could be a polytpye) + -> TcM (TcExpr, LIE) -tcExpr expr ty | isForAllTy ty = -- Polymorphic case - tcPolyExpr expr ty `thenTc` \ (expr', lie, _, _, _) -> - returnTc (expr', lie) +tcExpr expr ty | isQualifiedTy ty = -- Polymorphic case + tcPolyExpr expr ty `thenTc` \ (expr', lie, _, _, _) -> + returnTc (expr', lie) - | otherwise = -- Monomorphic case - tcMonoExpr expr ty + | otherwise = -- Monomorphic case + tcMonoExpr expr ty \end{code} @@ -110,9 +98,9 @@ tcExpr expr ty | isForAllTy ty = -- Polymorphic case -- tcPolyExpr is like tcMonoExpr, except that the expected type -- can be a polymorphic one. tcPolyExpr :: RenamedHsExpr - -> TcType s -- Expected type - -> TcM s (TcExpr s, LIE s, -- Generalised expr with expected type, and LIE - TcExpr s, TcTauType s, LIE s) -- Same thing, but instantiated; tau-type returned + -> TcType -- Expected type + -> TcM (TcExpr, LIE, -- Generalised expr with expected type, and LIE + TcExpr, TcTauType, LIE) -- Same thing, but instantiated; tau-type returned tcPolyExpr arg expected_arg_ty = -- Ha! The argument type of the function is a for-all type, @@ -120,16 +108,14 @@ tcPolyExpr arg expected_arg_ty -- To ensure that the forall'd type variables don't get unified with each -- other or any other types, we make fresh copy of the alleged type - tcInstSigTcType expected_arg_ty `thenNF_Tc` \ (sig_tyvars, sig_rho) -> + tcInstType expected_arg_ty `thenNF_Tc` \ (sig_tyvars, sig_theta, sig_tau) -> let - (sig_theta, sig_tau) = splitRhoTy sig_rho + free_tvs = tyVarsOfType expected_arg_ty in -- Type-check the arg and unify with expected type - tcExtendGlobalTyVars sig_tyvars ( - tcMonoExpr arg sig_tau - ) `thenTc` \ (arg', lie_arg) -> + tcMonoExpr arg sig_tau `thenTc` \ (arg', lie_arg) -> - -- Check that the arg_tyvars havn't been constrained + -- Check that the sig_tyvars havn't been constrained -- The interesting bit here is that we must include the free variables -- of the expected arg ty. Here's an example: -- runST (newVar True) @@ -140,28 +126,30 @@ tcPolyExpr arg expected_arg_ty -- Conclusion: include the free vars of the expected arg type in the -- list of "free vars" for the signature check. - tcExtendGlobalTyVars (tyVarSetToList (tyVarsOfType expected_arg_ty)) $ + tcExtendGlobalTyVars free_tvs $ + tcAddErrCtxtM (sigCtxt sig_msg sig_tyvars sig_theta sig_tau) $ - checkSigTyVars sig_tyvars sig_tau `thenTc` \ zonked_sig_tyvars -> - newDicts SignatureOrigin sig_theta `thenNF_Tc` \ (sig_dicts, dict_ids) -> - -- ToDo: better origin + newDicts SignatureOrigin sig_theta `thenNF_Tc` \ sig_dicts -> + tcSimplifyCheck + (text "the type signature of an expression") + sig_tyvars + sig_dicts lie_arg `thenTc` \ (free_insts, inst_binds) -> - tcSimplifyAndCheck - (text "tcPolyExpr") - (mkTyVarSet zonked_sig_tyvars) - sig_dicts lie_arg `thenTc` \ (free_insts, inst_binds) -> + checkSigTyVars sig_tyvars free_tvs `thenTc` \ zonked_sig_tyvars -> let -- This HsLet binds any Insts which came out of the simplification. -- It's a bit out of place here, but using AbsBind involves inventing -- a couple of new names which seems worse. generalised_arg = TyLam zonked_sig_tyvars $ - DictLam dict_ids $ - HsLet (MonoBind inst_binds [] Recursive) + DictLam (map instToId sig_dicts) $ + mkHsLet inst_binds $ arg' in returnTc ( generalised_arg, free_insts, arg', sig_tau, lie_arg ) + where + sig_msg = ptext SLIT("When checking an expression type signature") \end{code} %************************************************************************ @@ -172,8 +160,8 @@ tcPolyExpr arg expected_arg_ty \begin{code} tcMonoExpr :: RenamedHsExpr -- Expession to type check - -> TcTauType s -- Expected type (could be a type variable) - -> TcM s (TcExpr s, LIE s) + -> TcTauType -- Expected type (could be a type variable) + -> TcM (TcExpr, LIE) tcMonoExpr (HsVar name) res_ty = tcId name `thenNF_Tc` \ (expr', lie, id_ty) -> @@ -188,69 +176,10 @@ tcMonoExpr (HsVar name) res_ty returnTc (expr', lie) \end{code} -%************************************************************************ -%* * -\subsection{Literals} -%* * -%************************************************************************ - -Overloaded literals. - -\begin{code} -tcMonoExpr (HsLit (HsInt i)) res_ty - = newOverloadedLit (LiteralOrigin (HsInt i)) - (OverloadedIntegral i) - res_ty `thenNF_Tc` \ stuff -> - returnTc stuff - -tcMonoExpr (HsLit (HsFrac f)) res_ty - = newOverloadedLit (LiteralOrigin (HsFrac f)) - (OverloadedFractional f) - res_ty `thenNF_Tc` \ stuff -> - returnTc stuff - - -tcMonoExpr (HsLit lit@(HsLitLit s)) res_ty - = tcLookupClassByKey cCallableClassKey `thenNF_Tc` \ cCallableClass -> - newDicts (LitLitOrigin (_UNPK_ s)) - [(cCallableClass, [res_ty])] `thenNF_Tc` \ (dicts, _) -> - returnTc (HsLitOut lit res_ty, dicts) -\end{code} - -Primitive literals: - -\begin{code} -tcMonoExpr (HsLit lit@(HsCharPrim c)) res_ty - = unifyTauTy res_ty charPrimTy `thenTc_` - returnTc (HsLitOut lit charPrimTy, emptyLIE) - -tcMonoExpr (HsLit lit@(HsStringPrim s)) res_ty - = unifyTauTy res_ty addrPrimTy `thenTc_` - returnTc (HsLitOut lit addrPrimTy, emptyLIE) - -tcMonoExpr (HsLit lit@(HsIntPrim i)) res_ty - = unifyTauTy res_ty intPrimTy `thenTc_` - returnTc (HsLitOut lit intPrimTy, emptyLIE) - -tcMonoExpr (HsLit lit@(HsFloatPrim f)) res_ty - = unifyTauTy res_ty floatPrimTy `thenTc_` - returnTc (HsLitOut lit floatPrimTy, emptyLIE) - -tcMonoExpr (HsLit lit@(HsDoublePrim d)) res_ty - = unifyTauTy res_ty doublePrimTy `thenTc_` - returnTc (HsLitOut lit doublePrimTy, emptyLIE) -\end{code} - -Unoverloaded literals: - \begin{code} -tcMonoExpr (HsLit lit@(HsChar c)) res_ty - = unifyTauTy res_ty charTy `thenTc_` - returnTc (HsLitOut lit charTy, emptyLIE) - -tcMonoExpr (HsLit lit@(HsString str)) res_ty - = unifyTauTy res_ty stringTy `thenTc_` - returnTc (HsLitOut lit stringTy, emptyLIE) +tcMonoExpr (HsIPVar name) res_ty + = newIPDict (IPOcc name) name res_ty `thenNF_Tc` \ ip -> + returnNF_Tc (HsIPVar (instToId ip), unitLIE ip) \end{code} %************************************************************************ @@ -260,21 +189,15 @@ tcMonoExpr (HsLit lit@(HsString str)) res_ty %************************************************************************ \begin{code} -tcMonoExpr (HsPar expr) res_ty -- preserve parens so printing needn't guess where they go - = tcMonoExpr expr res_ty - --- perform the negate *before* overloading the integer, since the case --- of minBound on Ints fails otherwise. Could be done elsewhere, but --- convenient to do it here. +tcMonoExpr (HsLit lit) res_ty = tcLit lit res_ty +tcMonoExpr (HsOverLit lit) res_ty = newOverloadedLit (LiteralOrigin lit) lit res_ty +tcMonoExpr (HsPar expr) res_ty = tcMonoExpr expr res_ty -tcMonoExpr (NegApp (HsLit (HsInt i)) neg) res_ty - = tcMonoExpr (HsLit (HsInt (-i))) res_ty - -tcMonoExpr (NegApp expr neg) res_ty - = tcMonoExpr (HsApp neg expr) res_ty +tcMonoExpr (NegApp expr neg_name) res_ty + = tcMonoExpr (HsApp (HsVar neg_name) expr) res_ty tcMonoExpr (HsLam match) res_ty - = tcMatchExpected [] res_ty match `thenTc` \ (match',lie) -> + = tcMatchLambda match res_ty `thenTc` \ (match',lie) -> returnTc (HsLam match', lie) tcMonoExpr (HsApp e1 e2) res_ty = accum e1 [e2] @@ -335,51 +258,59 @@ arg/result types); unify them with the args/result; and store them for later use. \begin{code} -tcMonoExpr (CCall lbl args may_gc is_asm ignored_fake_result_ty) res_ty - = -- Get the callable and returnable classes. - tcLookupClassByKey cCallableClassKey `thenNF_Tc` \ cCallableClass -> - tcLookupClassByKey cReturnableClassKey `thenNF_Tc` \ cReturnableClass -> - tcLookupTyCon ioTyCon_NAME `thenTc` \ (_,_,ioTyCon) -> +tcMonoExpr e0@(HsCCall lbl args may_gc is_casm ignored_fake_result_ty) res_ty + + = getDOptsTc `thenNF_Tc` \ dflags -> + + checkTc (not (is_casm && dopt_HscLang dflags /= HscC)) + (vcat [text "_casm_ is only supported when compiling via C (-fvia-C).", + text "Either compile with -fvia-C, or, better, rewrite your code", + text "to use the foreign function interface. _casm_s are deprecated", + text "and support for them may one day disappear."]) + `thenTc_` + -- Get the callable and returnable classes. + tcLookupClass cCallableClassName `thenNF_Tc` \ cCallableClass -> + tcLookupClass cReturnableClassName `thenNF_Tc` \ cReturnableClass -> + tcLookupTyCon ioTyConName `thenNF_Tc` \ ioTyCon -> let new_arg_dict (arg, arg_ty) = newDicts (CCallOrigin (_UNPK_ lbl) (Just arg)) - [(cCallableClass, [arg_ty])] `thenNF_Tc` \ (arg_dicts, _) -> + [mkClassPred cCallableClass [arg_ty]] `thenNF_Tc` \ arg_dicts -> returnNF_Tc arg_dicts -- Actually a singleton bag result_origin = CCallOrigin (_UNPK_ lbl) Nothing {- Not an arg -} in -- Arguments - mapNF_Tc (\ _ -> newTyVarTy mkTypeKind) [1..(length args)] `thenNF_Tc` \ ty_vars -> - tcMonoExprs args ty_vars `thenTc` \ (args', args_lie) -> + let n_args = length args + tv_idxs | n_args == 0 = [] + | otherwise = [1..n_args] + in + newTyVarTys (length tv_idxs) openTypeKind `thenNF_Tc` \ arg_tys -> + tcMonoExprs args arg_tys `thenTc` \ (args', args_lie) -> - -- The argument types can be unboxed or boxed; the result - -- type must, however, be boxed since it's an argument to the IO + -- The argument types can be unlifted or lifted; the result + -- type must, however, be lifted since it's an argument to the IO -- type constructor. - newTyVarTy mkBoxedTypeKind `thenNF_Tc` \ result_ty -> + newTyVarTy liftedTypeKind `thenNF_Tc` \ result_ty -> let io_result_ty = mkTyConApp ioTyCon [result_ty] in - case tyConDataCons ioTyCon of { [ioDataCon] -> unifyTauTy res_ty io_result_ty `thenTc_` -- Construct the extra insts, which encode the -- constraints on the argument and result types. - mapNF_Tc new_arg_dict (zipEqual "tcMonoExpr:CCall" args ty_vars) `thenNF_Tc` \ ccarg_dicts_s -> - newDicts result_origin [(cReturnableClass, [result_ty])] `thenNF_Tc` \ (ccres_dict, _) -> - - returnTc (HsApp (HsVar (RealId ioDataCon) `TyApp` [result_ty]) - (CCall lbl args' may_gc is_asm io_result_ty), - -- do the wrapping in the newtype constructor here - foldr plusLIE ccres_dict ccarg_dicts_s `plusLIE` args_lie) - } + mapNF_Tc new_arg_dict (zipEqual "tcMonoExpr:CCall" args arg_tys) `thenNF_Tc` \ ccarg_dicts_s -> + newDicts result_origin [mkClassPred cReturnableClass [result_ty]] `thenNF_Tc` \ ccres_dict -> + returnTc (HsCCall lbl args' may_gc is_casm io_result_ty, + mkLIE (ccres_dict ++ concat ccarg_dicts_s) `plusLIE` args_lie) \end{code} \begin{code} -tcMonoExpr (HsSCC label expr) res_ty +tcMonoExpr (HsSCC lbl expr) res_ty = tcMonoExpr expr res_ty `thenTc` \ (expr', lie) -> - returnTc (HsSCC label expr', lie) + returnTc (HsSCC lbl expr', lie) tcMonoExpr (HsLet binds expr) res_ty = tcBindsAndThen @@ -390,7 +321,7 @@ tcMonoExpr (HsLet binds expr) res_ty where tc_expr = tcMonoExpr expr res_ty `thenTc` \ (expr', lie) -> returnTc (expr', lie) - combiner is_rec bind expr = HsLet (MonoBind bind [] is_rec) expr + combiner is_rec bind expr = HsLet (mkMonoBind bind [] is_rec) expr tcMonoExpr in_expr@(HsCase scrut matches src_loc) res_ty = tcAddSrcLoc src_loc $ @@ -402,8 +333,16 @@ tcMonoExpr in_expr@(HsCase scrut matches src_loc) res_ty -- case (map f) of -- (x:xs) -> ... -- will report that map is applied to too few arguments + -- + -- Not only that, but it's better to check the matches on their + -- own, so that we get the expected results for scoped type variables. + -- f x = case x of + -- (p::a, q::b) -> (q,p) + -- The above should work: the match (p,q) -> (q,p) is polymorphic as + -- claimed by the pattern signatures. But if we typechecked the + -- match with x in scope and x's type as the expected type, we'd be hosed. - tcMatchesCase res_ty matches `thenTc` \ (scrut_ty, matches', lie2) -> + tcMatchesCase matches res_ty `thenTc` \ (scrut_ty, matches', lie2) -> tcAddErrCtxt (caseScrutCtxt scrut) ( tcMonoExpr scrut scrut_ty @@ -427,45 +366,58 @@ tcMonoExpr expr@(HsDo do_or_lc stmts src_loc) res_ty \end{code} \begin{code} -tcMonoExpr in_expr@(ExplicitList exprs) res_ty -- Non-empty list +tcMonoExpr in_expr@(ExplicitList _ exprs) res_ty -- Non-empty list = unifyListTy res_ty `thenTc` \ elt_ty -> mapAndUnzipTc (tc_elt elt_ty) exprs `thenTc` \ (exprs', lies) -> - returnTc (ExplicitListOut elt_ty exprs', plusLIEs lies) + returnTc (ExplicitList elt_ty exprs', plusLIEs lies) where tc_elt elt_ty expr = tcAddErrCtxt (listCtxt expr) $ tcMonoExpr expr elt_ty -tcMonoExpr (ExplicitTuple exprs) res_ty - = unifyTupleTy (length exprs) res_ty `thenTc` \ arg_tys -> +tcMonoExpr (ExplicitTuple exprs boxity) res_ty + = unifyTupleTy boxity (length exprs) res_ty `thenTc` \ arg_tys -> mapAndUnzipTc (\ (expr, arg_ty) -> tcMonoExpr expr arg_ty) (exprs `zip` arg_tys) -- we know they're of equal length. - `thenTc` \ (exprs', lies) -> - returnTc (ExplicitTuple exprs', plusLIEs lies) + `thenTc` \ (exprs', lies) -> + returnTc (ExplicitTuple exprs' boxity, plusLIEs lies) -tcMonoExpr (RecordCon con_name _ rbinds) res_ty - = tcLookupGlobalValue con_name `thenNF_Tc` \ con_id -> +tcMonoExpr expr@(RecordCon con_name rbinds) res_ty + = tcAddErrCtxt (recordConCtxt expr) $ tcId con_name `thenNF_Tc` \ (con_expr, con_lie, con_tau) -> let - (_, record_ty) = splitFunTys con_tau + (_, record_ty) = tcSplitFunTys con_tau + (tycon, ty_args) = tcSplitTyConApp record_ty in - -- Con is syntactically constrained to be a data constructor - ASSERT( maybeToBool (splitAlgTyConApp_maybe record_ty ) ) + ASSERT( isAlgTyCon tycon ) unifyTauTy res_ty record_ty `thenTc_` -- Check that the record bindings match the constructor + -- con_name is syntactically constrained to be a data constructor + tcLookupDataCon con_name `thenTc` \ data_con -> let - bad_fields = badFields rbinds con_id + bad_fields = badFields rbinds data_con in - checkTc (null bad_fields) (badFieldsCon con_id bad_fields) `thenTc_` + if not (null bad_fields) then + mapNF_Tc (addErrTc . badFieldCon con_name) bad_fields `thenNF_Tc_` + failTc -- Fail now, because tcRecordBinds will crash on a bad field + else -- 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 (RealId con_id) con_expr rbinds', con_lie `plusLIE` rbinds_lie) + tcRecordBinds tycon ty_args rbinds `thenTc` \ (rbinds', rbinds_lie) -> + + let + (missing_s_fields, missing_fields) = missingFields rbinds data_con + in + checkTcM (null missing_s_fields) + (mapNF_Tc (addErrTc . missingStrictFieldCon con_name) missing_s_fields `thenNF_Tc_` + returnNF_Tc ()) `thenNF_Tc_` + doptsTc Opt_WarnMissingFields `thenNF_Tc` \ warn -> + checkTcM (not (warn && not (null missing_fields))) + (mapNF_Tc ((warnTc True) . missingFieldCon con_name) missing_fields `thenNF_Tc_` + returnNF_Tc ()) `thenNF_Tc_` + returnTc (RecordConOut data_con con_expr rbinds', con_lie `plusLIE` rbinds_lie) -- The main complication with RecordUpd is that we need to explicitly -- handle the *non-updated* fields. Consider: @@ -493,32 +445,46 @@ tcMonoExpr (RecordCon con_name _ rbinds) res_ty -- -- All this is done in STEP 4 below. -tcMonoExpr (RecordUpd record_expr rbinds) res_ty - = tcAddErrCtxt recordUpdCtxt $ +tcMonoExpr expr@(RecordUpd record_expr rbinds) res_ty + = tcAddErrCtxt (recordUpdCtxt expr) $ - -- STEP 1 - -- Figure out the tycon and data cons from the first field name + -- STEP 0 + -- Check that the field names are really field names ASSERT( not (null rbinds) ) let - ((first_field_name, _, _) : rest) = rbinds + field_names = [field_name | (field_name, _, _) <- rbinds] + in + mapNF_Tc tcLookupGlobal_maybe field_names `thenNF_Tc` \ maybe_sel_ids -> + let + bad_guys = [ addErrTc (notSelector field_name) + | (field_name, maybe_sel_id) <- field_names `zip` maybe_sel_ids, + case maybe_sel_id of + Just (AnId sel_id) -> not (isRecordSelector sel_id) + other -> True + ] 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 -> failWithTc (notSelector first_field_name) - ) `thenTc` \ sel_id -> + checkTcM (null bad_guys) (listNF_Tc bad_guys `thenNF_Tc_` failTc) `thenTc_` + + -- STEP 1 + -- Figure out the tycon and data cons from the first field name let - (_, tau) = splitForAllTys (idType sel_id) - Just (data_ty, _) = splitFunTy_maybe tau -- Must succeed since sel_id is a selector - (tycon, _, data_cons) = splitAlgTyConApp data_ty - (con_tyvars, theta, _, _, _, _) = dataConSig (head data_cons) + -- It's OK to use the non-tc splitters here (for a selector) + (Just (AnId sel_id) : _) = maybe_sel_ids + (_, _, tau) = tcSplitSigmaTy (idType sel_id) -- Selectors can be overloaded + -- when the data type has a context + data_ty = tcFunArgTy tau -- Must succeed since sel_id is a selector + tycon = tcTyConAppTyCon data_ty + data_cons = tyConDataCons tycon + (con_tyvars, _, _, _, _, _) = dataConSig (head data_cons) in tcInstTyVars con_tyvars `thenNF_Tc` \ (_, result_inst_tys, _) -> -- STEP 2 - -- Check for bad fields + -- Check that at least one constructor has all the named fields + -- i.e. has an empty set of bad fields returned by badFields checkTc (any (null . badFields rbinds) data_cons) (badFieldsUpd rbinds) `thenTc_` + -- STEP 3 -- Typecheck the update bindings. -- (Do this after checking for bad fields in case there's a field that @@ -527,7 +493,7 @@ tcMonoExpr (RecordUpd record_expr rbinds) res_ty result_record_ty = mkTyConApp tycon result_inst_tys in unifyTauTy res_ty result_record_ty `thenTc_` - tcRecordBinds result_record_ty rbinds `thenTc` \ (rbinds', rbinds_lie) -> + tcRecordBinds tycon result_inst_tys rbinds `thenTc` \ (rbinds', rbinds_lie) -> -- STEP 4 -- Use the un-updated fields to find a vector of booleans saying @@ -536,7 +502,7 @@ tcMonoExpr (RecordUpd record_expr rbinds) res_ty -- 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'] + upd_field_lbls = [recordSelectorFieldLabel sel_id | (sel_id, _, _) <- rbinds'] con_field_lbls_s = map dataConFieldLabels data_cons -- A constructor is only relevant to this process if @@ -548,8 +514,8 @@ tcMonoExpr (RecordUpd record_expr rbinds) res_ty 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 + | tyvar `elemVarSet` common_tyvars = returnNF_Tc result_inst_ty -- Same as result type + | otherwise = newTyVarTy liftedTypeKind -- Fresh type in mapNF_Tc mk_inst_ty (zip con_tyvars result_inst_tys) `thenNF_Tc` \ inst_tys -> @@ -571,65 +537,62 @@ tcMonoExpr (RecordUpd record_expr rbinds) res_ty -- union the ones that could participate in the update. let (tyvars, theta, _, _, _, _) = dataConSig (head data_cons) - inst_env = zipTyVarEnv tyvars result_inst_tys + inst_env = mkTopTyVarSubst tyvars result_inst_tys + theta' = substTheta inst_env theta in - tcInstTheta inst_env theta `thenNF_Tc` \ theta' -> - newDicts RecordUpdOrigin theta' `thenNF_Tc` \ (con_lie, dicts) -> + newDicts RecordUpdOrigin theta' `thenNF_Tc` \ dicts -> -- Phew! - returnTc (RecordUpdOut record_expr' result_record_ty dicts rbinds', - con_lie `plusLIE` record_lie `plusLIE` rbinds_lie) + returnTc (RecordUpdOut record_expr' record_ty result_record_ty (map instToId dicts) rbinds', + mkLIE dicts `plusLIE` record_lie `plusLIE` rbinds_lie) tcMonoExpr (ArithSeqIn seq@(From expr)) res_ty - = unifyListTy res_ty `thenTc` \ elt_ty -> - tcMonoExpr expr elt_ty `thenTc` \ (expr', lie1) -> + = unifyListTy res_ty `thenTc` \ elt_ty -> + tcMonoExpr expr elt_ty `thenTc` \ (expr', lie1) -> - tcLookupGlobalValueByKey enumFromClassOpKey `thenNF_Tc` \ sel_id -> + tcLookupGlobalId enumFromName `thenNF_Tc` \ sel_id -> newMethod (ArithSeqOrigin seq) - (RealId sel_id) [elt_ty] `thenNF_Tc` \ (lie2, enum_from_id) -> + sel_id [elt_ty] `thenNF_Tc` \ enum_from -> - returnTc (ArithSeqOut (HsVar enum_from_id) (From expr'), - lie1 `plusLIE` lie2) + returnTc (ArithSeqOut (HsVar (instToId enum_from)) (From expr'), + lie1 `plusLIE` unitLIE enum_from) tcMonoExpr in_expr@(ArithSeqIn seq@(FromThen expr1 expr2)) res_ty = tcAddErrCtxt (arithSeqCtxt in_expr) $ - unifyListTy res_ty `thenTc` \ elt_ty -> - tcMonoExpr expr1 elt_ty `thenTc` \ (expr1',lie1) -> - tcMonoExpr expr2 elt_ty `thenTc` \ (expr2',lie2) -> - tcLookupGlobalValueByKey enumFromThenClassOpKey `thenNF_Tc` \ sel_id -> - newMethod (ArithSeqOrigin seq) - (RealId sel_id) [elt_ty] `thenNF_Tc` \ (lie3, enum_from_then_id) -> + unifyListTy res_ty `thenTc` \ elt_ty -> + tcMonoExpr expr1 elt_ty `thenTc` \ (expr1',lie1) -> + tcMonoExpr expr2 elt_ty `thenTc` \ (expr2',lie2) -> + tcLookupGlobalId enumFromThenName `thenNF_Tc` \ sel_id -> + newMethod (ArithSeqOrigin seq) sel_id [elt_ty] `thenNF_Tc` \ enum_from_then -> - returnTc (ArithSeqOut (HsVar enum_from_then_id) - (FromThen expr1' expr2'), - lie1 `plusLIE` lie2 `plusLIE` lie3) + returnTc (ArithSeqOut (HsVar (instToId enum_from_then)) + (FromThen expr1' expr2'), + lie1 `plusLIE` lie2 `plusLIE` unitLIE enum_from_then) tcMonoExpr in_expr@(ArithSeqIn seq@(FromTo expr1 expr2)) res_ty = tcAddErrCtxt (arithSeqCtxt in_expr) $ - unifyListTy res_ty `thenTc` \ elt_ty -> - tcMonoExpr expr1 elt_ty `thenTc` \ (expr1',lie1) -> - tcMonoExpr expr2 elt_ty `thenTc` \ (expr2',lie2) -> - tcLookupGlobalValueByKey enumFromToClassOpKey `thenNF_Tc` \ sel_id -> - newMethod (ArithSeqOrigin seq) - (RealId sel_id) [elt_ty] `thenNF_Tc` \ (lie3, enum_from_to_id) -> + unifyListTy res_ty `thenTc` \ elt_ty -> + tcMonoExpr expr1 elt_ty `thenTc` \ (expr1',lie1) -> + tcMonoExpr expr2 elt_ty `thenTc` \ (expr2',lie2) -> + tcLookupGlobalId enumFromToName `thenNF_Tc` \ sel_id -> + newMethod (ArithSeqOrigin seq) sel_id [elt_ty] `thenNF_Tc` \ enum_from_to -> - returnTc (ArithSeqOut (HsVar enum_from_to_id) + returnTc (ArithSeqOut (HsVar (instToId enum_from_to)) (FromTo expr1' expr2'), - lie1 `plusLIE` lie2 `plusLIE` lie3) + lie1 `plusLIE` lie2 `plusLIE` unitLIE enum_from_to) tcMonoExpr in_expr@(ArithSeqIn seq@(FromThenTo expr1 expr2 expr3)) res_ty = tcAddErrCtxt (arithSeqCtxt in_expr) $ - unifyListTy res_ty `thenTc` \ elt_ty -> - tcMonoExpr expr1 elt_ty `thenTc` \ (expr1',lie1) -> - tcMonoExpr expr2 elt_ty `thenTc` \ (expr2',lie2) -> - tcMonoExpr expr3 elt_ty `thenTc` \ (expr3',lie3) -> - tcLookupGlobalValueByKey enumFromThenToClassOpKey `thenNF_Tc` \ sel_id -> - newMethod (ArithSeqOrigin seq) - (RealId sel_id) [elt_ty] `thenNF_Tc` \ (lie4, eft_id) -> - - returnTc (ArithSeqOut (HsVar eft_id) - (FromThenTo expr1' expr2' expr3'), - lie1 `plusLIE` lie2 `plusLIE` lie3 `plusLIE` lie4) + unifyListTy res_ty `thenTc` \ elt_ty -> + tcMonoExpr expr1 elt_ty `thenTc` \ (expr1',lie1) -> + tcMonoExpr expr2 elt_ty `thenTc` \ (expr2',lie2) -> + tcMonoExpr expr3 elt_ty `thenTc` \ (expr3',lie3) -> + tcLookupGlobalId enumFromThenToName `thenNF_Tc` \ sel_id -> + newMethod (ArithSeqOrigin seq) sel_id [elt_ty] `thenNF_Tc` \ eft -> + + returnTc (ArithSeqOut (HsVar (instToId eft)) + (FromThenTo expr1' expr2' expr3'), + lie1 `plusLIE` lie2 `plusLIE` lie3 `plusLIE` unitLIE eft) \end{code} %************************************************************************ @@ -640,11 +603,10 @@ tcMonoExpr in_expr@(ArithSeqIn seq@(FromThenTo expr1 expr2 expr3)) res_ty \begin{code} tcMonoExpr in_expr@(ExprWithTySig expr poly_ty) res_ty - = tcSetErrCtxt (exprSigCtxt in_expr) $ - tcHsType poly_ty `thenTc` \ sig_ty -> - tcInstSigType sig_ty `thenNF_Tc` \ sig_tc_ty -> + = tcHsSigType ExprSigCtxt poly_ty `thenTc` \ sig_tc_ty -> - if not (isForAllTy sig_tc_ty) then + tcAddErrCtxt (exprSigCtxt in_expr) $ + if not (isQualifiedTy sig_tc_ty) then -- Easy case unifyTauTy sig_tc_ty res_ty `thenTc_` tcMonoExpr expr sig_tc_ty @@ -661,26 +623,34 @@ tcMonoExpr in_expr@(ExprWithTySig expr poly_ty) res_ty -- If everything is ok, return the stuff unchanged, except for -- the effect of any substutions etc. We simply discard the - -- result of the tcSimplifyAndCheck (inside tcPolyExpr), except for any default + -- result of the tcSimplifyCheck (inside tcPolyExpr), except for any default -- resolution it may have done, which is recorded in the -- substitution. returnTc (expr, lie) \end{code} -Typecheck expression which in most cases will be an Id. +Implicit Parameter bindings. \begin{code} -tcExpr_id :: RenamedHsExpr - -> TcM s (TcExpr s, - LIE s, - TcType s) -tcExpr_id id_expr - = case id_expr of - HsVar name -> tcId name `thenNF_Tc` \ stuff -> - returnTc stuff - other -> newTyVarTy mkTypeKind `thenNF_Tc` \ id_ty -> - tcMonoExpr id_expr id_ty `thenTc` \ (id_expr', lie_id) -> - returnTc (id_expr', lie_id, id_ty) +tcMonoExpr (HsWith expr binds) res_ty + = tcMonoExpr expr res_ty `thenTc` \ (expr', expr_lie) -> + mapAndUnzipTc tcIPBind binds `thenTc` \ (pairs, bind_lies) -> + + -- If the binding binds ?x = E, we must now + -- discharge any ?x constraints in expr_lie + tcSimplifyIPs (map fst pairs) expr_lie `thenTc` \ (expr_lie', dict_binds) -> + let + binds' = [(instToId ip, rhs) | (ip,rhs) <- pairs] + expr'' = HsLet (mkMonoBind dict_binds [] Recursive) expr' + in + returnTc (HsWith expr'' binds', expr_lie' `plusLIE` plusLIEs bind_lies) + +tcIPBind (name, expr) + = newTyVarTy openTypeKind `thenTc` \ ty -> + tcGetSrcLoc `thenTc` \ loc -> + newIPDict (IPBind name) name ty `thenNF_Tc` \ ip -> + tcMonoExpr expr ty `thenTc` \ (expr', lie) -> + returnTc ((ip, expr'), lie) \end{code} %************************************************************************ @@ -691,10 +661,10 @@ tcExpr_id id_expr \begin{code} -tcApp :: RenamedHsExpr -> [RenamedHsExpr] -- Function and args - -> TcType s -- Expected result type of application - -> TcM s (TcExpr s, [TcExpr s], -- Translated fun and args - LIE s) +tcApp :: RenamedHsExpr -> [RenamedHsExpr] -- Function and args + -> TcType -- Expected result type of application + -> TcM (TcExpr, [TcExpr], -- Translated fun and args + LIE) tcApp fun args res_ty = -- First type-check the function @@ -717,7 +687,7 @@ tcApp fun args res_ty -- Check that the result type doesn't have any nested for-alls. -- For example, a "build" on its own is no good; it must be applied to something. checkTc (isTauTy actual_result_ty) - (lurkingRank2Err fun fun_ty) `thenTc_` + (lurkingRank2Err fun actual_result_ty) `thenTc_` returnTc (fun', args', lie_fun `plusLIE` plusLIEs lie_args_s) @@ -725,23 +695,26 @@ tcApp fun args res_ty -- If an error happens we try to figure out whether the -- function has been given too many or too few arguments, -- and say so -checkArgsCtxt fun args expected_res_ty actual_res_ty +checkArgsCtxt fun args expected_res_ty actual_res_ty tidy_env = zonkTcType expected_res_ty `thenNF_Tc` \ exp_ty' -> zonkTcType actual_res_ty `thenNF_Tc` \ act_ty' -> let - (exp_args, _) = splitFunTys exp_ty' - (act_args, _) = splitFunTys act_ty' + (env1, exp_ty'') = tidyOpenType tidy_env exp_ty' + (env2, act_ty'') = tidyOpenType env1 act_ty' + (exp_args, _) = tcSplitFunTys exp_ty'' + (act_args, _) = tcSplitFunTys act_ty'' + message | length exp_args < length act_args = wrongArgsCtxt "too few" fun args | length exp_args > length act_args = wrongArgsCtxt "too many" fun args | otherwise = appCtxt fun args in - returnNF_Tc message + returnNF_Tc (env2, message) -split_fun_ty :: TcType s -- The type of the function +split_fun_ty :: TcType -- The type of the function -> Int -- Number of arguments - -> TcM s ([TcType s], -- Function argument types - TcType s) -- Function result types + -> TcM ([TcType], -- Function argument types + TcType) -- Function result types split_fun_ty fun_ty 0 = returnTc ([], fun_ty) @@ -755,8 +728,8 @@ split_fun_ty fun_ty n \begin{code} tcArg :: RenamedHsExpr -- The function (for error messages) - -> (RenamedHsExpr, TcType s, Int) -- Actual argument and expected arg type - -> TcM s (TcExpr s, LIE s) -- Resulting argument and LIE + -> (RenamedHsExpr, TcType, Int) -- Actual argument and expected arg type + -> TcM (TcExpr, LIE) -- Resulting argument and LIE tcArg the_fun (arg, expected_arg_ty, arg_no) = tcAddErrCtxt (funAppCtxt the_fun arg arg_no) $ @@ -771,48 +744,23 @@ tcArg the_fun (arg, expected_arg_ty, arg_no) %************************************************************************ \begin{code} -tcId :: Name -> NF_TcM s (TcExpr s, LIE s, TcType s) - -tcId name - = -- Look up the Id and instantiate its type - tcLookupLocalValue name `thenNF_Tc` \ maybe_local -> - - case maybe_local of - Just tc_id -> instantiate_it (TcId tc_id) (idType tc_id) +tcId :: Name -> NF_TcM (TcExpr, LIE, TcType) +tcId name -- Look up the Id and instantiate its type + = tcLookupId name `thenNF_Tc` \ id -> + tcInstId id +\end{code} - Nothing -> tcLookupGlobalValue name `thenNF_Tc` \ id -> - tcInstType emptyTyVarEnv (idType id) `thenNF_Tc` \ inst_ty -> - let - (tyvars, rho) = splitForAllTys inst_ty - in - instantiate_it2 (RealId id) tyvars rho +Typecheck expression which in most cases will be an Id. - where - -- The instantiate_it loop runs round instantiating the Id. - -- It has to be a loop because we are now prepared to entertain - -- types like - -- f:: forall a. Eq a => forall b. Baz b => tau - -- We want to instantiate this to - -- f2::tau {f2 = f1 b (Baz b), f1 = f a (Eq a)} - instantiate_it tc_id_occ ty - = tcInstTcType ty `thenNF_Tc` \ (tyvars, rho) -> - instantiate_it2 tc_id_occ tyvars rho - - instantiate_it2 tc_id_occ tyvars rho - = 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 theta tau `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 - arg_tys = mkTyVarTys tyvars +\begin{code} +tcExpr_id :: RenamedHsExpr -> TcM (TcExpr, LIE, TcType) +tcExpr_id (HsVar name) = tcId name +tcExpr_id expr = newTyVarTy openTypeKind `thenNF_Tc` \ id_ty -> + tcMonoExpr expr id_ty `thenTc` \ (expr', lie_id) -> + returnTc (expr', lie_id, id_ty) \end{code} + %************************************************************************ %* * \subsection{@tcDoStmts@ typechecks a {\em list} of do statements} @@ -825,20 +773,21 @@ tcDoStmts do_or_lc stmts src_loc res_ty -- 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 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) -> - unifyTauTy res_ty result_ty `thenTc_` + -- If it's a comprehension we're dealing with, + -- force it to be a list comprehension. + -- (as of Haskell 98, monad comprehensions are no more.) + (case do_or_lc of + ListComp -> unifyListTy res_ty `thenTc` \ elt_ty -> + returnNF_Tc (mkTyConTy listTyCon, (mkListTy, elt_ty)) + + _ -> newTyVarTy (mkArrowKind liftedTypeKind liftedTypeKind) `thenNF_Tc` \ m_ty -> + newTyVarTy liftedTypeKind `thenNF_Tc` \ elt_ty -> + unifyTauTy res_ty (mkAppTy m_ty elt_ty) `thenTc_` + returnNF_Tc (m_ty, (mkAppTy m_ty, elt_ty)) + ) `thenNF_Tc` \ (tc_ty, m_ty) -> + + tcStmts (DoCtxt do_or_lc) m_ty stmts `thenTc` \ (stmts', stmts_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, @@ -848,27 +797,19 @@ tcDoStmts do_or_lc stmts src_loc res_ty -- 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 return_sel_id) [m] `thenNF_Tc` \ (return_lie, return_id) -> - newMethod DoOrigin - (RealId then_sel_id) [m] `thenNF_Tc` \ (then_lie, then_id) -> - newMethod DoOrigin - (RealId zero_sel_id) [m] `thenNF_Tc` \ (zero_lie, zero_id) -> + tcLookupGlobalId returnMName `thenNF_Tc` \ return_sel_id -> + tcLookupGlobalId thenMName `thenNF_Tc` \ then_sel_id -> + tcLookupGlobalId failMName `thenNF_Tc` \ fail_sel_id -> + newMethod DoOrigin return_sel_id [tc_ty] `thenNF_Tc` \ return_inst -> + newMethod DoOrigin then_sel_id [tc_ty] `thenNF_Tc` \ then_inst -> + newMethod DoOrigin fail_sel_id [tc_ty] `thenNF_Tc` \ fail_inst -> let - 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 + monad_lie = mkLIE [return_inst, then_inst, fail_inst] in - returnTc (HsDoOut do_or_lc stmts' return_id then_id zero_id res_ty src_loc, - final_lie `plusLIE` monad_lie) - + returnTc (HsDoOut do_or_lc stmts' + (instToId return_inst) (instToId then_inst) (instToId fail_inst) + res_ty src_loc, + stmts_lie `plusLIE` monad_lie) \end{code} @@ -880,55 +821,51 @@ tcDoStmts do_or_lc stmts src_loc res_ty Game plan for record bindings ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -For each binding - field = value -1. look up "field", to find its selector Id, which must have type - forall a1..an. T a1 .. an -> tau - where tau is the type of the field. +1. Find the TyCon for the bindings, from the first field label. + +2. Instantiate its tyvars and unify (T a1 .. an) with expected_ty. -2. Instantiate this type +For each binding field = value -3. Unify the (T a1 .. an) part with the "expected result type", which - is passed in. This checks that all the field labels come from the - same type. +3. Instantiate the field type (from the field label) using the type + envt from step 2. -4. Type check the value using tcArg, passing tau as the expected - argument type. +4 Type check the value using tcArg, passing the field type as + the expected argument type. This extends OK when the field types are universally quantified. -Actually, to save excessive creation of fresh type variables, -we \begin{code} tcRecordBinds - :: TcType s -- Expected type of whole record + :: TyCon -- Type constructor for the record + -> [TcType] -- Args of this type constructor -> RenamedRecordBinds - -> TcM s (TcRecordBinds s, LIE s) + -> TcM (TcRecordBinds, LIE) -tcRecordBinds expected_record_ty rbinds +tcRecordBinds tycon ty_args rbinds = mapAndUnzipTc do_bind rbinds `thenTc` \ (rbinds', lies) -> returnTc (rbinds', plusLIEs lies) where - do_bind (field_label, rhs, pun_flag) - = tcLookupGlobalValue field_label `thenNF_Tc` \ sel_id -> + tenv = mkTopTyVarSubst (tyConTyVars tycon) ty_args + + do_bind (field_lbl_name, rhs, pun_flag) + = tcLookupGlobalId field_lbl_name `thenNF_Tc` \ sel_id -> + let + field_lbl = recordSelectorFieldLabel sel_id + field_ty = substTy tenv (fieldLabelType field_lbl) + in ASSERT( isRecordSelector sel_id ) -- This lookup and assertion will surely succeed, because -- we check that the fields are indeed record selectors -- before calling tcRecordBinds + ASSERT2( fieldLabelTyCon field_lbl == tycon, ppr field_lbl ) + -- The caller of tcRecordBinds has already checked + -- that all the fields come from the same type - tcInstId sel_id `thenNF_Tc` \ (_, _, tau) -> + tcPolyExpr rhs field_ty `thenTc` \ (rhs', lie, _, _, _) -> - -- Record selectors all have type - -- forall a1..an. T a1 .. an -> tau - ASSERT( maybeToBool (splitFunTy_maybe tau) ) - let - -- Selector must have type RecordType -> FieldType - Just (record_ty, field_ty) = splitFunTy_maybe tau - in - unifyTauTy expected_record_ty record_ty `thenTc_` - tcPolyExpr rhs field_ty `thenTc` \ (rhs', lie, _, _, _) -> - returnTc ((RealId sel_id, rhs', pun_flag), lie) + returnTc ((sel_id, rhs', pun_flag), lie) badFields rbinds data_con = [field_name | (field_name, _, _) <- rbinds, @@ -936,6 +873,33 @@ badFields rbinds data_con ] where field_names = map fieldLabelName (dataConFieldLabels data_con) + +missingFields rbinds data_con + | null field_labels = ([], []) -- Not declared as a record; + -- But C{} is still valid + | otherwise + = (missing_strict_fields, other_missing_fields) + where + missing_strict_fields + = [ fl | (fl, str) <- field_info, + isMarkedStrict str, + not (fieldLabelName fl `elem` field_names_used) + ] + other_missing_fields + = [ fl | (fl, str) <- field_info, + not (isMarkedStrict str), + not (fieldLabelName fl `elem` field_names_used) + ] + + field_names_used = [ field_name | (field_name, _, _) <- rbinds ] + field_labels = dataConFieldLabels data_con + + field_info = zipEqual "missingFields" + field_labels + (drop (length ex_theta) (dataConStrictMarks data_con)) + -- The 'drop' is because dataConStrictMarks + -- includes the existential dictionaries + (_, _, _, ex_theta, _, _) = dataConSig data_con \end{code} %************************************************************************ @@ -945,7 +909,7 @@ badFields rbinds data_con %************************************************************************ \begin{code} -tcMonoExprs :: [RenamedHsExpr] -> [TcType s] -> TcM s ([TcExpr s], LIE s) +tcMonoExprs :: [RenamedHsExpr] -> [TcType] -> TcM ([TcExpr], LIE) tcMonoExprs [] [] = returnTc ([], emptyLIE) tcMonoExprs (expr:exprs) (ty:tys) @@ -955,17 +919,36 @@ tcMonoExprs (expr:exprs) (ty:tys) \end{code} -% ================================================= +%************************************************************************ +%* * +\subsection{Literals} +%* * +%************************************************************************ -Errors and contexts -~~~~~~~~~~~~~~~~~~~ +Overloaded literals. -Mini-utils: \begin{code} -pp_nest_hang :: String -> SDoc -> SDoc -pp_nest_hang label stuff = nest 2 (hang (text label) 4 stuff) +tcLit :: HsLit -> TcType -> TcM (TcExpr, LIE) +tcLit (HsLitLit s _) res_ty + = tcLookupClass cCallableClassName `thenNF_Tc` \ cCallableClass -> + newDicts (LitLitOrigin (_UNPK_ s)) + [mkClassPred cCallableClass [res_ty]] `thenNF_Tc` \ dicts -> + returnTc (HsLit (HsLitLit s res_ty), mkLIE dicts) + +tcLit lit res_ty + = unifyTauTy res_ty (simpleHsLitTy lit) `thenTc_` + returnTc (HsLit lit, emptyLIE) \end{code} + +%************************************************************************ +%* * +\subsection{Errors and contexts} +%* * +%************************************************************************ + +Mini-utils: + Boring and alphabetical: \begin{code} arithSeqCtxt expr @@ -999,7 +982,7 @@ funAppCtxt fun arg arg_no 4 (quotes (ppr arg)) wrongArgsCtxt too_many_or_few fun args - = hang (ptext SLIT("Probable cause:") <+> ppr fun + = hang (ptext SLIT("Probable cause:") <+> quotes (ppr fun) <+> ptext SLIT("is applied to") <+> text too_many_or_few <+> ptext SLIT("arguments in the call")) 4 (parens (ppr the_app)) @@ -1007,17 +990,14 @@ wrongArgsCtxt too_many_or_few fun args the_app = foldl HsApp fun args -- Used in error messages appCtxt fun args - = ptext SLIT("In the application") <+> (ppr the_app) + = ptext SLIT("In the application") <+> quotes (ppr the_app) where the_app = foldl HsApp fun args -- Used in error messages lurkingRank2Err fun fun_ty = hang (hsep [ptext SLIT("Illegal use of"), quotes (ppr fun)]) 4 (vcat [ptext SLIT("It is applied to too few arguments"), - ptext SLIT("so that the result type has for-alls in it")]) - -rank2ArgCtxt arg expected_arg_ty - = ptext SLIT("In a polymorphic function argument:") <+> ppr arg + ptext SLIT("so that the result type has for-alls in it:") <+> ppr fun_ty]) badFieldsUpd rbinds = hang (ptext SLIT("No constructor has all these fields:")) @@ -1025,12 +1005,19 @@ badFieldsUpd rbinds where fields = [field | (field, _, _) <- rbinds] -recordUpdCtxt = ptext SLIT("In a record update construct") - -badFieldsCon con fields - = hsep [ptext SLIT("Constructor"), ppr con, - ptext SLIT("does not have field(s):"), pprQuotedList fields] +recordUpdCtxt expr = ptext SLIT("In the record update:") <+> ppr expr +recordConCtxt expr = ptext SLIT("In the record construction:") <+> ppr expr notSelector field = hsep [quotes (ppr field), ptext SLIT("is not a record selector")] + +missingStrictFieldCon :: Name -> FieldLabel -> SDoc +missingStrictFieldCon con field + = hsep [ptext SLIT("Constructor") <+> quotes (ppr con), + ptext SLIT("does not have the required strict field"), quotes (ppr field)] + +missingFieldCon :: Name -> FieldLabel -> SDoc +missingFieldCon con field + = hsep [ptext SLIT("Field") <+> quotes (ppr field), + ptext SLIT("is not initialised")] \end{code}