X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Fcompiler%2Ftypecheck%2FTcExpr.lhs;h=cf94f27f19c2157dcbe917e09508dcd825735453;hb=c5a65b1704212e3f4354841ff480c660a3b51fb6;hp=f622d1cb266eabeef6e458b7420a7e259dcc99ff;hpb=6c872fff42025a842e8500ddbb13fdcca60eaf75;p=ghc-hetmet.git diff --git a/ghc/compiler/typecheck/TcExpr.lhs b/ghc/compiler/typecheck/TcExpr.lhs index f622d1c..cf94f27 100644 --- a/ghc/compiler/typecheck/TcExpr.lhs +++ b/ghc/compiler/typecheck/TcExpr.lhs @@ -4,88 +4,71 @@ \section[TcExpr]{Typecheck an expression} \begin{code} -module TcExpr ( tcApp, tcExpr, tcPolyExpr, tcId ) where +module TcExpr ( tcCheckSigma, tcCheckRho, tcInferRho, tcMonoExpr ) where #include "HsVersions.h" -import HsSyn ( HsExpr(..), HsLit(..), ArithSeqInfo(..), - HsBinds(..), MonoBinds(..), Stmt(..), StmtCtxt(..), - mkMonoBind, nullMonoBinds - ) -import RnHsSyn ( RenamedHsExpr, RenamedRecordBinds ) -import TcHsSyn ( TcExpr, TcRecordBinds, mkHsConApp, - mkHsTyApp, mkHsLet, maybeBoxedPrimType - ) - -import TcMonad -import BasicTypes ( RecFlag(..) ) - -import Inst ( Inst, InstOrigin(..), OverloadedLit(..), - LIE, emptyLIE, unitLIE, consLIE, plusLIE, plusLIEs, - lieToList, listToLIE, - newOverloadedLit, newMethod, newIPDict, - instOverloadedFun, newDicts, newClassDicts, - getIPsOfLIE, instToId, ipToId +#ifdef GHCI /* Only if bootstrapped */ +import {-# SOURCE #-} TcSplice( tcSpliceExpr, tcBracket ) +import Id ( Id ) +import TcType ( isTauTy ) +import TcEnv ( checkWellStaged ) +import HsSyn ( nlHsApp ) +import qualified DsMeta +#endif + +import HsSyn ( HsExpr(..), LHsExpr, HsLit(..), ArithSeqInfo(..), recBindFields, + HsMatchContext(..), HsRecordBinds, mkHsApp, nlHsVar ) +import TcHsSyn ( hsLitType, mkHsDictApp, mkHsTyApp, (<$>) ) +import TcRnMonad +import TcUnify ( Expected(..), newHole, zapExpectedType, zapExpectedTo, tcSubExp, tcGen, + unifyFunTy, zapToListTy, zapToPArrTy, zapToTupleTy ) +import BasicTypes ( isMarkedStrict ) +import Inst ( InstOrigin(..), + newOverloadedLit, newMethodFromName, newIPDict, + newDicts, newMethodWithGivenTy, + instToId, tcInstCall, tcInstDataCon ) import TcBinds ( tcBindsAndThen ) -import TcEnv ( tcInstId, - tcLookupValue, tcLookupClassByKey, - tcLookupValueByKey, - tcExtendGlobalTyVars, tcLookupValueMaybe, - tcLookupTyCon, tcLookupDataCon +import TcEnv ( tcLookup, tcLookupId, checkProcLevel, + tcLookupDataCon, tcLookupGlobalId ) -import TcMatches ( tcMatchesCase, tcMatchLambda, tcStmts ) -import TcMonoType ( tcHsSigType, checkSigTyVars, sigCtxt ) +import TcArrows ( tcProc ) +import TcMatches ( tcMatchesCase, tcMatchLambda, tcDoStmts, tcThingWithSig, TcMatchCtxt(..) ) +import TcHsType ( tcHsSigType, UserTypeCtxt(..) ) import TcPat ( badFieldCon ) -import TcSimplify ( tcSimplify, tcSimplifyAndCheck, partitionPredsOfLIE ) -import TcType ( TcType, TcTauType, - tcInstTyVars, - tcInstTcType, tcSplitRhoTy, - newTyVarTy, newTyVarTy_OpenKind, zonkTcType ) - -import Class ( Class ) -import FieldLabel ( FieldLabel, fieldLabelName, fieldLabelType - ) -import Id ( idType, recordSelectorFieldLabel, - isRecordSelector, - Id, mkVanillaId - ) -import DataCon ( dataConFieldLabels, dataConSig, - dataConStrictMarks, StrictnessMark(..) +import TcMType ( tcInstTyVars, tcInstType, newTyVarTy, zonkTcType ) +import TcType ( TcType, TcSigmaType, TcRhoType, TyVarDetails(VanillaTv), + tcSplitFunTys, tcSplitTyConApp, mkTyVarTys, + isSigmaTy, mkFunTy, mkFunTys, + mkTyConApp, tyVarsOfTypes, isLinearPred, + tcSplitSigmaTy, tidyOpenType ) -import Name ( Name, getName ) -import Type ( mkFunTy, mkAppTy, mkTyVarTy, mkTyVarTys, - ipName_maybe, - splitFunTy_maybe, splitFunTys, isNotUsgTy, - mkTyConApp, - splitForAllTys, splitRhoTy, - isTauTy, tyVarsOfType, tyVarsOfTypes, - isForAllTy, splitAlgTyConApp, splitAlgTyConApp_maybe, - boxedTypeKind, mkArrowKind, - tidyOpenType +import Kind ( openTypeKind, liftedTypeKind, argTypeKind ) + +import FieldLabel ( FieldLabel, fieldLabelName, fieldLabelType, fieldLabelTyCon ) +import Id ( idType, recordSelectorFieldLabel, isRecordSelector ) +import DataCon ( DataCon, dataConFieldLabels, dataConStrictMarks, dataConWrapId ) +import Name ( Name ) +import TyCon ( TyCon, tyConTyVars, tyConTheta, tyConDataCons ) +import Subst ( mkTopTyVarSubst, substTheta, substTy ) +import VarSet ( emptyVarSet, elemVarSet ) +import TysWiredIn ( boolTy ) +import PrelNames ( enumFromName, enumFromThenName, + enumFromToName, enumFromThenToName, + enumFromToPName, enumFromThenToPName ) -import Subst ( mkTopTyVarSubst, substClasses ) -import UsageSPUtils ( unannotTy ) -import VarSet ( emptyVarSet, unionVarSet, elemVarSet, mkVarSet ) -import TyCon ( tyConDataCons ) -import TysPrim ( intPrimTy, charPrimTy, doublePrimTy, - floatPrimTy, addrPrimTy - ) -import TysWiredIn ( boolTy, charTy, stringTy ) -import PrelInfo ( ioTyCon_NAME ) -import TcUnify ( unifyTauTy, unifyFunTy, unifyListTy, unifyTupleTy, - unifyUnboxedTupleTy ) -import Unique ( cCallableClassKey, cReturnableClassKey, - enumFromClassOpKey, enumFromThenClassOpKey, - enumFromToClassOpKey, enumFromThenToClassOpKey, - thenMClassOpKey, failMClassOpKey, returnMClassOpKey - ) -import Outputable -import Maybes ( maybeToBool, mapMaybe ) import ListSetOps ( minusList ) +import CmdLineOpts +import HscTypes ( TyThing(..) ) +import SrcLoc ( Located(..), unLoc, getLoc ) import Util -import CmdLineOpts ( opt_WarnMissingFields ) +import Outputable +import FastString +#ifdef DEBUG +import TyCon ( isAlgTyCon ) +#endif \end{code} %************************************************************************ @@ -95,182 +78,106 @@ import CmdLineOpts ( opt_WarnMissingFields ) %************************************************************************ \begin{code} -tcExpr :: RenamedHsExpr -- Expession to type check - -> TcType -- Expected type (could be a polytpye) - -> TcM s (TcExpr, LIE) - -tcExpr expr ty | isForAllTy ty = -- Polymorphic case - tcPolyExpr expr ty `thenTc` \ (expr', lie, _, _, _) -> - returnTc (expr', lie) - - | otherwise = -- Monomorphic case - tcMonoExpr expr ty +-- tcCheckSigma does type *checking*; it's passed the expected type of the result +tcCheckSigma :: LHsExpr Name -- Expession to type check + -> TcSigmaType -- Expected type (could be a polytpye) + -> TcM (LHsExpr TcId) -- Generalised expr with expected type + +tcCheckSigma expr expected_ty + = traceTc (text "tcExpr" <+> (ppr expected_ty $$ ppr expr)) `thenM_` + tc_expr' expr expected_ty + +tc_expr' expr sigma_ty + | isSigmaTy sigma_ty + = tcGen sigma_ty emptyVarSet ( + \ rho_ty -> tcCheckRho expr rho_ty + ) `thenM` \ (gen_fn, expr') -> + returnM (L (getLoc expr') (gen_fn <$> unLoc expr')) + +tc_expr' expr rho_ty -- Monomorphic case + = tcCheckRho expr rho_ty \end{code} - -%************************************************************************ -%* * -\subsection{@tcPolyExpr@ typchecks an application} -%* * -%************************************************************************ +Typecheck expression which in most cases will be an Id. +The expression can return a higher-ranked type, such as + (forall a. a->a) -> Int +so we must create a hole to pass in as the expected tyvar. \begin{code} --- tcPolyExpr is like tcMonoExpr, except that the expected type --- can be a polymorphic one. -tcPolyExpr :: RenamedHsExpr - -> TcType -- Expected type - -> TcM s (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, - -- An example of rank-2 polymorphism. - - -- 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 - tcInstTcType expected_arg_ty `thenNF_Tc` \ (sig_tyvars, sig_rho) -> - let - (sig_theta, sig_tau) = splitRhoTy sig_rho - in - -- Type-check the arg and unify with expected type - tcMonoExpr arg sig_tau `thenTc` \ (arg', lie_arg) -> - - -- 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) - -- Here, if we don't make a check, we'll get a type (ST s (MutVar s Bool)) - -- for (newVar True), with s fresh. Then we unify with the runST's arg type - -- forall s'. ST s' a. That unifies s' with s, and a with MutVar s Bool. - -- So now s' isn't unconstrained because it's linked to a. - -- Conclusion: include the free vars of the expected arg type in the - -- list of "free vars" for the signature check. - - tcExtendGlobalTyVars (tyVarsOfType expected_arg_ty) $ - tcAddErrCtxtM (sigCtxt sig_msg expected_arg_ty) $ - - checkSigTyVars sig_tyvars `thenTc` \ zonked_sig_tyvars -> - - newDicts SignatureOrigin sig_theta `thenNF_Tc` \ (sig_dicts, dict_ids) -> - -- ToDo: better origin - tcSimplifyAndCheck - (text "the type signature of an expression") - (mkVarSet zonked_sig_tyvars) - sig_dicts lie_arg `thenTc` \ (free_insts, inst_binds) -> - - 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 $ - mkHsLet inst_binds $ - arg' - in - returnTc ( generalised_arg, free_insts, - arg', sig_tau, lie_arg ) - where - sig_msg ty = sep [ptext SLIT("In an expression with expected type:"), - nest 4 (ppr ty)] +tcCheckRho :: LHsExpr Name -> TcRhoType -> TcM (LHsExpr TcId) +tcCheckRho expr rho_ty = tcMonoExpr expr (Check rho_ty) + +tcInferRho :: LHsExpr Name -> TcM (LHsExpr TcId, TcRhoType) +tcInferRho (L loc (HsVar name)) = addSrcSpan loc $ + do { (e,ty) <- tcId name; return (L loc e, ty)} +tcInferRho expr = newHole `thenM` \ hole -> + tcMonoExpr expr (Infer hole) `thenM` \ expr' -> + readMutVar hole `thenM` \ rho_ty -> + returnM (expr', rho_ty) \end{code} + + %************************************************************************ %* * -\subsection{The TAUT rules for variables} +\subsection{The TAUT rules for variables}TcExpr %* * %************************************************************************ \begin{code} -tcMonoExpr :: RenamedHsExpr -- Expession to type check - -> TcTauType -- Expected type (could be a type variable) - -> TcM s (TcExpr, LIE) - -tcMonoExpr (HsVar name) res_ty - = tcId name `thenNF_Tc` \ (expr', lie, id_ty) -> - unifyTauTy res_ty id_ty `thenTc_` - - -- 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 id_ty) - (lurkingRank2Err name id_ty) `thenTc_` - - returnTc (expr', lie) +tcMonoExpr :: LHsExpr Name -- Expession to type check + -> Expected TcRhoType -- Expected type (could be a type variable) + -- Definitely no foralls at the top + -- Can be a 'hole'. + -> TcM (LHsExpr TcId) + +tcMonoExpr (L loc expr) res_ty + = addSrcSpan loc (do { expr' <- tc_expr expr res_ty + ; return (L loc expr') }) + +tc_expr :: HsExpr Name -> Expected TcRhoType -> TcM (HsExpr TcId) +tc_expr (HsVar name) res_ty + = tcId name `thenM` \ (expr', id_ty) -> + tcSubExp res_ty id_ty `thenM` \ co_fn -> + returnM (co_fn <$> expr') + +tc_expr (HsIPVar ip) res_ty + = -- Implicit parameters must have a *tau-type* not a + -- type scheme. We enforce this by creating a fresh + -- type variable as its type. (Because res_ty may not + -- be a tau-type.) + newTyVarTy argTypeKind `thenM` \ ip_ty -> + -- argTypeKind: it can't be an unboxed tuple + newIPDict (IPOccOrigin ip) ip ip_ty `thenM` \ (ip', inst) -> + extendLIE inst `thenM_` + tcSubExp res_ty ip_ty `thenM` \ co_fn -> + returnM (co_fn <$> HsIPVar ip') \end{code} -\begin{code} -tcMonoExpr (HsIPVar name) res_ty - -- ZZ What's the `id' used for here... - = let id = mkVanillaId name res_ty in - tcGetInstLoc (OccurrenceOf id) `thenNF_Tc` \ loc -> - newIPDict name res_ty loc `thenNF_Tc` \ ip -> - returnNF_Tc (HsIPVar (instToId ip), unitLIE ip) -\end{code} %************************************************************************ %* * -\subsection{Literals} +\subsection{Expressions type signatures} %* * %************************************************************************ -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 -> - newClassDicts (LitLitOrigin (_UNPK_ s)) - [(cCallableClass,[res_ty])] `thenNF_Tc` \ (dicts, _) -> - returnTc (HsLitOut lit res_ty, dicts) +tc_expr in_expr@(ExprWithTySig expr poly_ty) res_ty + = addErrCtxt (exprCtxt in_expr) $ + tcHsSigType ExprSigCtxt poly_ty `thenM` \ sig_tc_ty -> + tcThingWithSig sig_tc_ty (tcCheckRho expr) res_ty `thenM` \ (co_fn, expr') -> + returnM (co_fn <$> unLoc expr') + -- ToDo: nasty unLoc + +tc_expr (HsType ty) res_ty + = failWithTc (text "Can't handle type argument:" <+> ppr ty) + -- This is the syntax for type applications that I was planning + -- but there are difficulties (e.g. what order for type args) + -- so it's not enabled yet. + -- Can't eliminate it altogether from the parser, because the + -- same parser parses *patterns*. \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) -\end{code} %************************************************************************ %* * @@ -279,34 +186,30 @@ 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 (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 (HsLam match) res_ty - = tcMatchLambda match res_ty `thenTc` \ (match',lie) -> - returnTc (HsLam match', lie) - -tcMonoExpr (HsApp e1 e2) res_ty = accum e1 [e2] - where - accum (HsApp e1 e2) args = accum e1 (e2:args) - accum fun args - = tcApp fun args res_ty `thenTc` \ (fun', args', lie) -> - returnTc (foldl HsApp fun' args', lie) - --- equivalent to (op e1) e2: -tcMonoExpr (OpApp arg1 op fix arg2) res_ty - = tcApp op [arg1,arg2] res_ty `thenTc` \ (op', [arg1', arg2'], lie) -> - returnTc (OpApp arg1' op' fix arg2', lie) +tc_expr (HsPar expr) res_ty = tcMonoExpr expr res_ty `thenM` \ expr' -> + returnM (HsPar expr') +tc_expr (HsSCC lbl expr) res_ty = tcMonoExpr expr res_ty `thenM` \ expr' -> + returnM (HsSCC lbl expr') +tc_expr (HsCoreAnn lbl expr) res_ty = tcMonoExpr expr res_ty `thenM` \ expr' -> -- hdaume: core annotation + returnM (HsCoreAnn lbl expr') + +tc_expr (HsLit lit) res_ty = tcLit lit res_ty + +tc_expr (HsOverLit lit) res_ty + = zapExpectedType res_ty liftedTypeKind `thenM` \ res_ty' -> + newOverloadedLit (LiteralOrigin lit) lit res_ty' `thenM` \ lit_expr -> + returnM (unLoc lit_expr) -- ToDo: nasty unLoc + +tc_expr (NegApp expr neg_name) res_ty + = tc_expr (HsApp (nlHsVar neg_name) expr) res_ty + -- ToDo: use tcSyntaxName + +tc_expr (HsLam match) res_ty + = tcMatchLambda match res_ty `thenM` \ match' -> + returnM (HsLam match') + +tc_expr (HsApp e1 e2) res_ty + = tcApp e1 [e2] res_ty \end{code} Note that the operators in sections are expected to be binary, and @@ -320,100 +223,48 @@ a type error will occur if they aren't. -- or just -- op e -tcMonoExpr in_expr@(SectionL arg op) res_ty - = tcApp op [arg] res_ty `thenTc` \ (op', [arg'], lie) -> - - -- Check that res_ty is a function type - -- Without this check we barf in the desugarer on - -- f op = (3 `op`) - -- because it tries to desugar to - -- f op = \r -> 3 op r - -- so (3 `op`) had better be a function! - tcAddErrCtxt (sectionLAppCtxt in_expr) $ - unifyFunTy res_ty `thenTc_` - - returnTc (SectionL arg' op', lie) +tc_expr in_expr@(SectionL arg1 op) res_ty + = tcInferRho op `thenM` \ (op', op_ty) -> + split_fun_ty op_ty 2 {- two args -} `thenM` \ ([arg1_ty, arg2_ty], op_res_ty) -> + tcArg op (arg1, arg1_ty, 1) `thenM` \ arg1' -> + addErrCtxt (exprCtxt in_expr) $ + tcSubExp res_ty (mkFunTy arg2_ty op_res_ty) `thenM` \ co_fn -> + returnM (co_fn <$> SectionL arg1' op') -- Right sections, equivalent to \ x -> x op expr, or -- \ x -> op x expr -tcMonoExpr in_expr@(SectionR op expr) res_ty - = tcExpr_id op `thenTc` \ (op', lie1, op_ty) -> - tcAddErrCtxt (sectionRAppCtxt in_expr) $ - split_fun_ty op_ty 2 {- two args -} `thenTc` \ ([arg1_ty, arg2_ty], op_res_ty) -> - tcMonoExpr expr arg2_ty `thenTc` \ (expr',lie2) -> - unifyTauTy res_ty (mkFunTy arg1_ty op_res_ty) `thenTc_` - returnTc (SectionR op' expr', lie1 `plusLIE` lie2) -\end{code} - -The interesting thing about @ccall@ is that it is just a template -which we instantiate by filling in details about the types of its -argument and result (ie minimal typechecking is performed). So, the -basic story is that we allocate a load of type variables (to hold the -arg/result types); unify them with the args/result; and store them for -later use. +tc_expr in_expr@(SectionR op arg2) res_ty + = tcInferRho op `thenM` \ (op', op_ty) -> + split_fun_ty op_ty 2 {- two args -} `thenM` \ ([arg1_ty, arg2_ty], op_res_ty) -> + tcArg op (arg2, arg2_ty, 2) `thenM` \ arg2' -> + addErrCtxt (exprCtxt in_expr) $ + tcSubExp res_ty (mkFunTy arg1_ty op_res_ty) `thenM` \ co_fn -> + returnM (co_fn <$> SectionR op' arg2') -\begin{code} -tcMonoExpr (HsCCall 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 `thenNF_Tc` \ ioTyCon -> - let - new_arg_dict (arg, arg_ty) - = newClassDicts (CCallOrigin (_UNPK_ lbl) (Just arg)) - [(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 - let n_args = length args - tv_idxs | n_args == 0 = [] - | otherwise = [1..n_args] - in - mapNF_Tc (\ _ -> newTyVarTy_OpenKind) tv_idxs `thenNF_Tc` \ arg_tys -> - tcMonoExprs args arg_tys `thenTc` \ (args', args_lie) -> +-- equivalent to (op e1) e2: - -- The argument types can be unboxed or boxed; the result - -- type must, however, be boxed since it's an argument to the IO - -- type constructor. - newTyVarTy boxedTypeKind `thenNF_Tc` \ result_ty -> - let - io_result_ty = mkTyConApp ioTyCon [result_ty] - [ioDataCon] = tyConDataCons ioTyCon - in - 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 arg_tys) `thenNF_Tc` \ ccarg_dicts_s -> - newClassDicts result_origin [(cReturnableClass, [result_ty])] `thenNF_Tc` \ (ccres_dict, _) -> - returnTc (mkHsConApp ioDataCon [result_ty] [HsCCall 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) +tc_expr in_expr@(OpApp arg1 op fix arg2) res_ty + = tcInferRho op `thenM` \ (op', op_ty) -> + split_fun_ty op_ty 2 {- two args -} `thenM` \ ([arg1_ty, arg2_ty], op_res_ty) -> + tcArg op (arg1, arg1_ty, 1) `thenM` \ arg1' -> + tcArg op (arg2, arg2_ty, 2) `thenM` \ arg2' -> + addErrCtxt (exprCtxt in_expr) $ + tcSubExp res_ty op_res_ty `thenM` \ co_fn -> + returnM (OpApp arg1' op' fix arg2') \end{code} \begin{code} -tcMonoExpr (HsSCC lbl expr) res_ty - = tcMonoExpr expr res_ty `thenTc` \ (expr', lie) -> - returnTc (HsSCC lbl expr', lie) - -tcMonoExpr (HsLet binds expr) res_ty +tc_expr (HsLet binds (L loc expr)) res_ty = tcBindsAndThen - combiner + glue binds -- Bindings to check - tc_expr `thenTc` \ (expr', lie) -> - returnTc (expr', lie) + (tc_expr expr res_ty) where - tc_expr = tcMonoExpr expr res_ty `thenTc` \ (expr', lie) -> - returnTc (expr', lie) - combiner is_rec bind expr = HsLet (mkMonoBind bind [] is_rec) expr + glue bind expr = HsLet [bind] (L loc expr) -tcMonoExpr in_expr@(HsCase scrut matches src_loc) res_ty - = tcAddSrcLoc src_loc $ - tcAddErrCtxt (caseCtxt in_expr) $ +tc_expr in_expr@(HsCase scrut matches) res_ty + = addErrCtxt (caseCtxt in_expr) $ -- Typecheck the case alternatives first. -- The case patterns tend to give good type info to use @@ -421,95 +272,99 @@ 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 matches res_ty `thenTc` \ (scrut_ty, matches', lie2) -> - - tcAddErrCtxt (caseScrutCtxt scrut) ( - tcMonoExpr scrut scrut_ty - ) `thenTc` \ (scrut',lie1) -> - - returnTc (HsCase scrut' matches' src_loc, plusLIE lie1 lie2) - -tcMonoExpr (HsIf pred b1 b2 src_loc) res_ty - = tcAddSrcLoc src_loc $ - tcAddErrCtxt (predCtxt pred) ( - tcMonoExpr pred boolTy ) `thenTc` \ (pred',lie1) -> - - tcMonoExpr b1 res_ty `thenTc` \ (b1',lie2) -> - tcMonoExpr b2 res_ty `thenTc` \ (b2',lie3) -> - returnTc (HsIf pred' b1' b2' src_loc, plusLIE lie1 (plusLIE lie2 lie3)) -\end{code} -\begin{code} -tcMonoExpr expr@(HsDo do_or_lc stmts src_loc) res_ty - = tcDoStmts do_or_lc stmts src_loc res_ty -\end{code} + tcMatchesCase match_ctxt matches res_ty `thenM` \ (scrut_ty, matches') -> -\begin{code} -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) + addErrCtxt (caseScrutCtxt scrut) ( + tcCheckRho scrut scrut_ty + ) `thenM` \ scrut' -> + + returnM (HsCase scrut' matches') + where + match_ctxt = MC { mc_what = CaseAlt, + mc_body = tcMonoExpr } + +tc_expr (HsIf pred b1 b2) res_ty + = addErrCtxt (predCtxt pred) ( + tcCheckRho pred boolTy ) `thenM` \ pred' -> + + zapExpectedType res_ty openTypeKind `thenM` \ res_ty' -> + -- C.f. the call to zapToType in TcMatches.tcMatches + + tcCheckRho b1 res_ty' `thenM` \ b1' -> + tcCheckRho b2 res_ty' `thenM` \ b2' -> + returnM (HsIf pred' b1' b2') + +tc_expr (HsDo do_or_lc stmts method_names _) res_ty + = zapExpectedType res_ty liftedTypeKind `thenM` \ res_ty' -> + -- All comprehensions yield a monotype of kind * + tcDoStmts do_or_lc stmts method_names res_ty' `thenM` \ (stmts', methods') -> + returnM (HsDo do_or_lc stmts' methods' res_ty') + +tc_expr in_expr@(ExplicitList _ exprs) res_ty -- Non-empty list + = zapToListTy res_ty `thenM` \ elt_ty -> + mappM (tc_elt elt_ty) exprs `thenM` \ exprs' -> + returnM (ExplicitList elt_ty exprs') + where + tc_elt elt_ty expr + = addErrCtxt (listCtxt expr) $ + tcCheckRho expr elt_ty + +tc_expr in_expr@(ExplicitPArr _ exprs) res_ty -- maybe empty + = zapToPArrTy res_ty `thenM` \ elt_ty -> + mappM (tc_elt elt_ty) exprs `thenM` \ exprs' -> + returnM (ExplicitPArr elt_ty exprs') where tc_elt elt_ty expr - = tcAddErrCtxt (listCtxt expr) $ - tcMonoExpr expr elt_ty - -tcMonoExpr (ExplicitTuple exprs boxed) res_ty - = (if boxed - then unifyTupleTy (length exprs) res_ty - else unifyUnboxedTupleTy (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' boxed, plusLIEs lies) - -tcMonoExpr expr@(RecordCon con_name rbinds) res_ty - = tcAddErrCtxt (recordConCtxt expr) $ - tcId con_name `thenNF_Tc` \ (con_expr, con_lie, con_tau) -> + = addErrCtxt (parrCtxt expr) $ + tcCheckRho expr elt_ty + +tc_expr (ExplicitTuple exprs boxity) res_ty + = zapToTupleTy boxity (length exprs) res_ty `thenM` \ arg_tys -> + tcCheckRhos exprs arg_tys `thenM` \ exprs' -> + returnM (ExplicitTuple exprs' boxity) + +tc_expr (HsProc pat cmd) res_ty + = tcProc pat cmd res_ty `thenM` \ (pat', cmd') -> + returnM (HsProc pat' cmd') +\end{code} + +%************************************************************************ +%* * + Record construction and update +%* * +%************************************************************************ + +\begin{code} +tc_expr expr@(RecordCon con@(L _ con_name) rbinds) res_ty + = addErrCtxt (recordConCtxt expr) $ + addLocM tcId con `thenM` \ (con_expr, con_tau) -> let - (_, record_ty) = splitFunTys con_tau + (_, record_ty) = tcSplitFunTys con_tau + (tycon, ty_args) = tcSplitTyConApp record_ty in - ASSERT( maybeToBool (splitAlgTyConApp_maybe record_ty ) ) - unifyTauTy res_ty record_ty `thenTc_` + ASSERT( isAlgTyCon tycon ) + zapExpectedTo res_ty record_ty `thenM_` -- Check that the record bindings match the constructor -- con_name is syntactically constrained to be a data constructor - tcLookupDataCon con_name `thenTc` \ (data_con, _, _) -> + tcLookupDataCon con_name `thenM` \ data_con -> let bad_fields = badFields rbinds data_con in - 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 + if notNull bad_fields then + mappM (addErrTc . badFieldCon data_con) bad_fields `thenM_` + failM -- Fail now, because tcRecordBinds will crash on a bad field else -- Typecheck the record bindings - tcRecordBinds record_ty rbinds `thenTc` \ (rbinds', rbinds_lie) -> + tcRecordBinds tycon ty_args rbinds `thenM` \ rbinds' -> - let - missing_s_fields = missingStrictFields rbinds data_con - in - checkTcM (null missing_s_fields) - (mapNF_Tc (addErrTc . missingStrictFieldCon con_name) missing_s_fields `thenNF_Tc_` - returnNF_Tc ()) `thenNF_Tc_` - let - missing_fields = missingFields rbinds data_con - in - checkTcM (not (opt_WarnMissingFields && not (null missing_fields))) - (mapNF_Tc ((warnTc True) . missingFieldCon con_name) missing_fields `thenNF_Tc_` - returnNF_Tc ()) `thenNF_Tc_` + -- Check for missing fields + checkMissingFields data_con rbinds `thenM_` - returnTc (RecordConOut data_con con_expr rbinds', con_lie `plusLIE` rbinds_lie) + getSrcSpanM `thenM` \ loc -> + returnM (RecordConOut data_con (L loc con_expr) rbinds') -- The main complication with RecordUpd is that we need to explicitly -- handle the *non-updated* fields. Consider: @@ -537,45 +392,43 @@ tcMonoExpr expr@(RecordCon con_name rbinds) res_ty -- -- All this is done in STEP 4 below. -tcMonoExpr expr@(RecordUpd record_expr rbinds) res_ty - = tcAddErrCtxt (recordUpdCtxt expr) $ +tc_expr expr@(RecordUpd record_expr rbinds) res_ty + = addErrCtxt (recordUpdCtxt expr) $ -- STEP 0 -- Check that the field names are really field names - ASSERT( not (null rbinds) ) + ASSERT( notNull rbinds ) let - field_names = [field_name | (field_name, _, _) <- rbinds] + field_names = map fst rbinds in - mapNF_Tc tcLookupValueMaybe field_names `thenNF_Tc` \ maybe_sel_ids -> + mappM (tcLookupGlobalId.unLoc) field_names `thenM` \ sel_ids -> + -- The renamer has already checked that they + -- are all in scope let - bad_guys = [field_name | (field_name, maybe_sel_id) <- field_names `zip` maybe_sel_ids, - case maybe_sel_id of - Nothing -> True - Just sel_id -> not (isRecordSelector sel_id) + bad_guys = [ addSrcSpan loc $ addErrTc (notSelector field_name) + | (L loc field_name, sel_id) <- field_names `zip` sel_ids, + not (isRecordSelector sel_id) -- Excludes class ops ] in - mapNF_Tc (addErrTc . notSelector) bad_guys `thenTc_` - if not (null bad_guys) then - failTc - else + checkM (null bad_guys) (sequenceM bad_guys `thenM_` failM) `thenM_` -- STEP 1 -- Figure out the tycon and data cons from the first field name let - (Just sel_id : _) = maybe_sel_ids - (_, tau) = ASSERT( isNotUsgTy (idType sel_id) ) - 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) + sel_id : _ = sel_ids + field_lbl = recordSelectorFieldLabel sel_id -- We've failed already if + tycon = fieldLabelTyCon field_lbl -- it's not a field label + data_cons = tyConDataCons tycon + tycon_tyvars = tyConTyVars tycon -- The data cons use the same type vars in - tcInstTyVars con_tyvars `thenNF_Tc` \ (_, result_inst_tys, _) -> + tcInstTyVars VanillaTv tycon_tyvars `thenM` \ (_, result_inst_tys, inst_env) -> -- STEP 2 -- 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_` + (badFieldsUpd rbinds) `thenM_` -- STEP 3 -- Typecheck the update bindings. @@ -584,8 +437,8 @@ tcMonoExpr expr@(RecordUpd record_expr rbinds) res_ty let 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) -> + zapExpectedTo res_ty result_record_ty `thenM_` + tcRecordBinds tycon result_inst_tys rbinds `thenM` \ rbinds' -> -- STEP 4 -- Use the un-updated fields to find a vector of booleans saying @@ -594,7 +447,7 @@ tcMonoExpr expr@(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 | (sel_id, _, _) <- rbinds'] + upd_field_lbls = map recordSelectorFieldLabel (recBindFields rbinds') con_field_lbls_s = map dataConFieldLabels data_cons -- A constructor is only relevant to this process if @@ -606,193 +459,141 @@ tcMonoExpr expr@(RecordUpd record_expr rbinds) res_ty common_tyvars = tyVarsOfTypes (map fieldLabelType non_upd_field_lbls) mk_inst_ty (tyvar, result_inst_ty) - | tyvar `elemVarSet` common_tyvars = returnNF_Tc result_inst_ty -- Same as result type - | otherwise = newTyVarTy boxedTypeKind -- Fresh type + | tyvar `elemVarSet` common_tyvars = returnM 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 -> + mappM mk_inst_ty (zip tycon_tyvars result_inst_tys) `thenM` \ inst_tys -> -- STEP 5 -- Typecheck the expression to be updated let record_ty = mkTyConApp tycon inst_tys in - tcMonoExpr record_expr record_ty `thenTc` \ (record_expr', record_lie) -> + tcCheckRho record_expr record_ty `thenM` \ record_expr' -> -- 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. + -- do pattern matching over the data cons. -- - -- 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. + -- What dictionaries do we need? + -- We just take the context of the type constructor let - (tyvars, theta, _, _, _, _) = dataConSig (head data_cons) - inst_env = mkTopTyVarSubst tyvars result_inst_tys - theta' = substClasses inst_env theta + theta' = substTheta inst_env (tyConTheta tycon) in - newClassDicts RecordUpdOrigin theta' `thenNF_Tc` \ (con_lie, dicts) -> + newDicts RecordUpdOrigin theta' `thenM` \ dicts -> + extendLIEs dicts `thenM_` -- Phew! - returnTc (RecordUpdOut record_expr' result_record_ty dicts rbinds', - con_lie `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) -> - - tcLookupValueByKey enumFromClassOpKey `thenNF_Tc` \ sel_id -> - newMethod (ArithSeqOrigin seq) - sel_id [elt_ty] `thenNF_Tc` \ (lie2, enum_from_id) -> - - returnTc (ArithSeqOut (HsVar enum_from_id) (From expr'), - lie1 `plusLIE` lie2) - -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) -> - tcLookupValueByKey enumFromThenClassOpKey `thenNF_Tc` \ sel_id -> - newMethod (ArithSeqOrigin seq) - sel_id [elt_ty] `thenNF_Tc` \ (lie3, enum_from_then_id) -> - - returnTc (ArithSeqOut (HsVar enum_from_then_id) - (FromThen expr1' expr2'), - lie1 `plusLIE` lie2 `plusLIE` lie3) - -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) -> - tcLookupValueByKey enumFromToClassOpKey `thenNF_Tc` \ sel_id -> - newMethod (ArithSeqOrigin seq) - sel_id [elt_ty] `thenNF_Tc` \ (lie3, enum_from_to_id) -> - - returnTc (ArithSeqOut (HsVar enum_from_to_id) - (FromTo expr1' expr2'), - lie1 `plusLIE` lie2 `plusLIE` lie3) - -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) -> - tcLookupValueByKey enumFromThenToClassOpKey `thenNF_Tc` \ sel_id -> - newMethod (ArithSeqOrigin seq) - 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) + returnM (RecordUpdOut record_expr' record_ty result_record_ty rbinds') \end{code} + %************************************************************************ %* * -\subsection{Expressions type signatures} + Arithmetic sequences e.g. [a,b..] + and their parallel-array counterparts e.g. [: a,b.. :] + %* * %************************************************************************ \begin{code} -tcMonoExpr in_expr@(ExprWithTySig expr poly_ty) res_ty - = tcSetErrCtxt (exprSigCtxt in_expr) $ - tcHsSigType poly_ty `thenTc` \ sig_tc_ty -> - - if not (isForAllTy sig_tc_ty) then - -- Easy case - unifyTauTy sig_tc_ty res_ty `thenTc_` - tcMonoExpr expr sig_tc_ty - - else -- Signature is polymorphic - tcPolyExpr expr sig_tc_ty `thenTc` \ (_, _, expr, expr_ty, lie) -> - - -- Now match the signature type with res_ty. - -- We must not do this earlier, because res_ty might well - -- mention variables free in the environment, and we'd get - -- bogus complaints about not being able to for-all the - -- sig_tyvars - unifyTauTy res_ty expr_ty `thenTc_` - - -- 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 - -- resolution it may have done, which is recorded in the - -- substitution. - returnTc (expr, lie) +tc_expr (ArithSeqIn seq@(From expr)) res_ty + = zapToListTy res_ty `thenM` \ elt_ty -> + tcCheckRho expr elt_ty `thenM` \ expr' -> + + newMethodFromName (ArithSeqOrigin seq) + elt_ty enumFromName `thenM` \ enum_from -> + + returnM (ArithSeqOut (nlHsVar enum_from) (From expr')) + +tc_expr in_expr@(ArithSeqIn seq@(FromThen expr1 expr2)) res_ty + = addErrCtxt (arithSeqCtxt in_expr) $ + zapToListTy res_ty `thenM` \ elt_ty -> + tcCheckRho expr1 elt_ty `thenM` \ expr1' -> + tcCheckRho expr2 elt_ty `thenM` \ expr2' -> + newMethodFromName (ArithSeqOrigin seq) + elt_ty enumFromThenName `thenM` \ enum_from_then -> + + returnM (ArithSeqOut (nlHsVar enum_from_then) (FromThen expr1' expr2')) + + +tc_expr in_expr@(ArithSeqIn seq@(FromTo expr1 expr2)) res_ty + = addErrCtxt (arithSeqCtxt in_expr) $ + zapToListTy res_ty `thenM` \ elt_ty -> + tcCheckRho expr1 elt_ty `thenM` \ expr1' -> + tcCheckRho expr2 elt_ty `thenM` \ expr2' -> + newMethodFromName (ArithSeqOrigin seq) + elt_ty enumFromToName `thenM` \ enum_from_to -> + + returnM (ArithSeqOut (nlHsVar enum_from_to) (FromTo expr1' expr2')) + +tc_expr in_expr@(ArithSeqIn seq@(FromThenTo expr1 expr2 expr3)) res_ty + = addErrCtxt (arithSeqCtxt in_expr) $ + zapToListTy res_ty `thenM` \ elt_ty -> + tcCheckRho expr1 elt_ty `thenM` \ expr1' -> + tcCheckRho expr2 elt_ty `thenM` \ expr2' -> + tcCheckRho expr3 elt_ty `thenM` \ expr3' -> + newMethodFromName (ArithSeqOrigin seq) + elt_ty enumFromThenToName `thenM` \ eft -> + + returnM (ArithSeqOut (nlHsVar eft) (FromThenTo expr1' expr2' expr3')) + +tc_expr in_expr@(PArrSeqIn seq@(FromTo expr1 expr2)) res_ty + = addErrCtxt (parrSeqCtxt in_expr) $ + zapToPArrTy res_ty `thenM` \ elt_ty -> + tcCheckRho expr1 elt_ty `thenM` \ expr1' -> + tcCheckRho expr2 elt_ty `thenM` \ expr2' -> + newMethodFromName (PArrSeqOrigin seq) + elt_ty enumFromToPName `thenM` \ enum_from_to -> + + returnM (PArrSeqOut (nlHsVar enum_from_to) (FromTo expr1' expr2')) + +tc_expr in_expr@(PArrSeqIn seq@(FromThenTo expr1 expr2 expr3)) res_ty + = addErrCtxt (parrSeqCtxt in_expr) $ + zapToPArrTy res_ty `thenM` \ elt_ty -> + tcCheckRho expr1 elt_ty `thenM` \ expr1' -> + tcCheckRho expr2 elt_ty `thenM` \ expr2' -> + tcCheckRho expr3 elt_ty `thenM` \ expr3' -> + newMethodFromName (PArrSeqOrigin seq) + elt_ty enumFromThenToPName `thenM` \ eft -> + + returnM (PArrSeqOut (nlHsVar eft) (FromThenTo expr1' expr2' expr3')) + +tc_expr (PArrSeqIn _) _ + = panic "TcExpr.tcMonoExpr: Infinite parallel array!" + -- the parser shouldn't have generated it and the renamer shouldn't have + -- let it through \end{code} -Implicit Parameter bindings. + +%************************************************************************ +%* * + Template Haskell +%* * +%************************************************************************ \begin{code} -tcMonoExpr (HsWith expr binds) res_ty - = tcMonoExpr expr res_ty `thenTc` \ (expr', lie) -> - tcIPBinds binds `thenTc` \ (binds', types, lie2) -> - partitionPredsOfLIE isBound lie `thenTc` \ (ips, lie', dict_binds) -> - pprTrace "tcMonoExpr With" (ppr (ips, lie', dict_binds)) $ - let expr'' = if nullMonoBinds dict_binds - then expr' - else HsLet (mkMonoBind (revBinds dict_binds) [] NonRecursive) - expr' - in - tcCheckIPBinds binds' types ips `thenTc_` - returnTc (HsWith expr'' binds', lie' `plusLIE` lie2) - where isBound p - = case ipName_maybe p of - Just n -> n `elem` names - Nothing -> False - names = map fst binds - -- revBinds is used because tcSimplify outputs the bindings - -- out-of-order. it's not a problem elsewhere because these - -- bindings are normally used in a recursive let - -- ZZ probably need to find a better solution - revBinds (b1 `AndMonoBinds` b2) = - (revBinds b2) `AndMonoBinds` (revBinds b1) - revBinds b = b - -tcIPBinds ((name, expr) : binds) - = newTyVarTy_OpenKind `thenTc` \ ty -> - tcGetSrcLoc `thenTc` \ loc -> - let id = ipToId name ty loc in - tcMonoExpr expr ty `thenTc` \ (expr', lie) -> - zonkTcType ty `thenTc` \ ty' -> - tcIPBinds binds `thenTc` \ (binds', types, lie2) -> - returnTc ((id, expr') : binds', ty : types, lie `plusLIE` lie2) -tcIPBinds [] = returnTc ([], [], emptyLIE) - -tcCheckIPBinds binds types ips - = foldrTc tcCheckIPBind (getIPsOfLIE ips) (zip binds types) - --- ZZ how do we use the loc? -tcCheckIPBind bt@((v, _), t1) ((n, t2) : ips) | getName v == n - = unifyTauTy t1 t2 `thenTc_` - tcCheckIPBind bt ips `thenTc` \ ips' -> - returnTc ips' -tcCheckIPBind bt (ip : ips) - = tcCheckIPBind bt ips `thenTc` \ ips' -> - returnTc (ip : ips') -tcCheckIPBind bt [] - = returnTc [] +#ifdef GHCI /* Only if bootstrapped */ + -- Rename excludes these cases otherwise +tc_expr (HsSpliceE splice) res_ty = tcSpliceExpr splice res_ty +tc_expr (HsBracket brack) res_ty = do { e <- tcBracket brack res_ty + ; return (unLoc e) } +#endif /* GHCI */ \end{code} -Typecheck expression which in most cases will be an Id. + +%************************************************************************ +%* * + Catch-all +%* * +%************************************************************************ \begin{code} -tcExpr_id :: RenamedHsExpr - -> TcM s (TcExpr, - LIE, - TcType) -tcExpr_id id_expr - = case id_expr of - HsVar name -> tcId name `thenNF_Tc` \ stuff -> - returnTc stuff - other -> newTyVarTy_OpenKind `thenNF_Tc` \ id_ty -> - tcMonoExpr id_expr id_ty `thenTc` \ (id_expr', lie_id) -> - returnTc (id_expr', lie_id, id_ty) +tc_expr other _ = pprPanic "tcMonoExpr" (ppr other) \end{code} + %************************************************************************ %* * \subsection{@tcApp@ typchecks an application} @@ -801,79 +602,100 @@ tcExpr_id id_expr \begin{code} -tcApp :: RenamedHsExpr -> [RenamedHsExpr] -- Function and args - -> TcType -- Expected result type of application - -> TcM s (TcExpr, [TcExpr], -- Translated fun and args - LIE) +tcApp :: LHsExpr Name -> [LHsExpr Name] -- Function and args + -> Expected TcRhoType -- Expected result type of application + -> TcM (HsExpr TcId) -- Translated fun and args + +tcApp (L _ (HsApp e1 e2)) args res_ty + = tcApp e1 (e2:args) res_ty -- Accumulate the arguments tcApp fun args res_ty = -- First type-check the function - tcExpr_id fun `thenTc` \ (fun', lie_fun, fun_ty) -> + tcInferRho fun `thenM` \ (fun', fun_ty) -> - tcAddErrCtxt (wrongArgsCtxt "too many" fun args) ( + addErrCtxt (wrongArgsCtxt "too many" fun args) ( + traceTc (text "tcApp" <+> (ppr fun $$ ppr fun_ty)) `thenM_` split_fun_ty fun_ty (length args) - ) `thenTc` \ (expected_arg_tys, actual_result_ty) -> + ) `thenM` \ (expected_arg_tys, actual_result_ty) -> + + -- Unify with expected result before (was: after) type-checking the args + -- so that the info from res_ty (was: args) percolates to args (was actual_result_ty). + -- This is when we might detect a too-few args situation. + -- (One can think of cases when the opposite order would give + -- a better error message.) + -- [March 2003: I'm experimenting with putting this first. Here's an + -- example where it actually makes a real difference + -- class C t a b | t a -> b + -- instance C Char a Bool + -- + -- data P t a = forall b. (C t a b) => MkP b + -- data Q t = MkQ (forall a. P t a) + + -- f1, f2 :: Q Char; + -- f1 = MkQ (MkP True) + -- f2 = MkQ (MkP True :: forall a. P Char a) + -- + -- With the change, f1 will type-check, because the 'Char' info from + -- the signature is propagated into MkQ's argument. With the check + -- in the other order, the extra signature in f2 is reqd.] - -- Unify with expected result before type-checking the args - -- This is when we might detect a too-few args situation - tcAddErrCtxtM (checkArgsCtxt fun args res_ty actual_result_ty) ( - unifyTauTy res_ty actual_result_ty - ) `thenTc_` + addErrCtxtM (checkArgsCtxt fun args res_ty actual_result_ty) + (tcSubExp res_ty actual_result_ty) `thenM` \ co_fn -> -- Now typecheck the args - mapAndUnzipTc (tcArg fun) - (zip3 args expected_arg_tys [1..]) `thenTc` \ (args', lie_args_s) -> - - -- 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_` + mappM (tcArg fun) + (zip3 args expected_arg_tys [1..]) `thenM` \ args' -> - returnTc (fun', args', lie_fun `plusLIE` plusLIEs lie_args_s) + returnM (co_fn <$> unLoc (foldl mkHsApp fun' args')) -- 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 tidy_env - = zonkTcType expected_res_ty `thenNF_Tc` \ exp_ty' -> - zonkTcType actual_res_ty `thenNF_Tc` \ act_ty' -> +-- and say so. +-- The ~(Check...) is because in the Infer case the tcSubExp +-- definitely won't fail, so we can be certain we're in the Check branch +checkArgsCtxt fun args ~(Check expected_res_ty) actual_res_ty tidy_env + = zonkTcType expected_res_ty `thenM` \ exp_ty' -> + zonkTcType actual_res_ty `thenM` \ act_ty' -> let (env1, exp_ty'') = tidyOpenType tidy_env exp_ty' (env2, act_ty'') = tidyOpenType env1 act_ty' - (exp_args, _) = splitFunTys exp_ty'' - (act_args, _) = splitFunTys act_ty'' + (exp_args, _) = tcSplitFunTys exp_ty'' + (act_args, _) = tcSplitFunTys act_ty'' + + len_act_args = length act_args + len_exp_args = length exp_args - 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 + message | len_exp_args < len_act_args = wrongArgsCtxt "too few" fun args + | len_exp_args > len_act_args = wrongArgsCtxt "too many" fun args + | otherwise = appCtxt fun args in - returnNF_Tc (env2, message) + returnM (env2, message) -split_fun_ty :: TcType -- The type of the function - -> Int -- Number of arguments - -> TcM s ([TcType], -- Function argument types - TcType) -- Function result types +split_fun_ty :: TcRhoType -- The type of the function + -> Int -- Number of arguments + -> TcM ([TcType], -- Function argument types + TcType) -- Function result types split_fun_ty fun_ty 0 - = returnTc ([], fun_ty) + = returnM ([], fun_ty) split_fun_ty fun_ty n = -- Expect the function to have type A->B - unifyFunTy fun_ty `thenTc` \ (arg_ty, res_ty) -> - split_fun_ty res_ty (n-1) `thenTc` \ (arg_tys, final_res_ty) -> - returnTc (arg_ty:arg_tys, final_res_ty) + unifyFunTy fun_ty `thenM` \ (arg_ty, res_ty) -> + split_fun_ty res_ty (n-1) `thenM` \ (arg_tys, final_res_ty) -> + returnM (arg_ty:arg_tys, final_res_ty) \end{code} \begin{code} -tcArg :: RenamedHsExpr -- The function (for error messages) - -> (RenamedHsExpr, TcType, Int) -- Actual argument and expected arg type - -> TcM s (TcExpr, LIE) -- Resulting argument and LIE +tcArg :: LHsExpr Name -- The function (for error messages) + -> (LHsExpr Name, TcSigmaType, Int) -- Actual argument and expected arg type + -> TcM (LHsExpr TcId) -- Resulting argument tcArg the_fun (arg, expected_arg_ty, arg_no) - = tcAddErrCtxt (funAppCtxt the_fun arg arg_no) $ - tcExpr arg expected_arg_ty + = addErrCtxt (funAppCtxt the_fun arg arg_no) $ + tcCheckSigma arg expected_arg_ty \end{code} @@ -883,99 +705,140 @@ tcArg the_fun (arg, expected_arg_ty, arg_no) %* * %************************************************************************ -Between the renamer and the first invocation of the UsageSP inference, -identifiers read from interface files will have usage information in -their types, whereas other identifiers will not. The unannotTy here -in @tcId@ prevents this information from pointlessly propagating -further prior to the first usage inference. +tcId instantiates an occurrence of an Id. +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)} + +The -fno-method-sharing flag controls what happens so far as the LIE +is concerned. The default case is that for an overloaded function we +generate a "method" Id, and add the Method Inst to the LIE. So you get +something like + f :: Num a => a -> a + f = /\a (d:Num a) -> let m = (+) a d in \ (x:a) -> m x x +If you specify -fno-method-sharing, the dictionary application +isn't shared, so we get + f :: Num a => a -> a + f = /\a (d:Num a) (x:a) -> (+) a d x x +This gets a bit less sharing, but + a) it's better for RULEs involving overloaded functions + b) perhaps fewer separated lambdas \begin{code} -tcId :: Name -> NF_TcM s (TcExpr, LIE, TcType) - -tcId name - = -- Look up the Id and instantiate its type - tcLookupValueMaybe name `thenNF_Tc` \ maybe_local -> - - case maybe_local of - Just tc_id -> instantiate_it (OccurrenceOf tc_id) (HsVar tc_id) (unannotTy (idType tc_id)) - - Nothing -> tcLookupValue name `thenNF_Tc` \ id -> - tcInstId id `thenNF_Tc` \ (tyvars, theta, tau) -> - instantiate_it2 (OccurrenceOf id) (HsVar id) tyvars theta tau - +tcId :: Name -> TcM (HsExpr TcId, TcRhoType) +tcId name -- Look up the Id and instantiate its type + = -- First check whether it's a DataCon + -- Reason: we must not forget to chuck in the + -- constraints from their "silly context" + tcLookup name `thenM` \ thing -> + case thing of { + AGlobal (ADataCon data_con) -> inst_data_con data_con + ; AGlobal (AnId id) -> loop (HsVar id) (idType id) + -- A global cannot possibly be ill-staged + -- nor does it need the 'lifting' treatment + + ; ATcId id th_level proc_level -> tc_local_id id th_level proc_level + ; other -> pprPanic "tcId" (ppr name $$ ppr thing) + } 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 orig fun ty - = tcInstTcType ty `thenNF_Tc` \ (tyvars, rho) -> - tcSplitRhoTy rho `thenNF_Tc` \ (theta, tau) -> - instantiate_it2 orig fun tyvars theta tau - - instantiate_it2 orig fun tyvars theta tau - = if null theta then -- Is it overloaded? - returnNF_Tc (mkHsTyApp fun arg_tys, emptyLIE, tau) - else - -- Yes, it's overloaded - instOverloadedFun orig fun arg_tys theta tau `thenNF_Tc` \ (fun', lie1) -> - instantiate_it orig fun' tau `thenNF_Tc` \ (expr, lie2, final_tau) -> - returnNF_Tc (expr, lie1 `plusLIE` lie2, final_tau) - - where - arg_tys = mkTyVarTys tyvars -\end{code} - -%************************************************************************ -%* * -\subsection{@tcDoStmts@ typechecks a {\em list} of do statements} -%* * -%************************************************************************ -\begin{code} -tcDoStmts do_or_lc stmts src_loc res_ty - = -- get the Monad and MonadZero classes - -- create type consisting of a fresh monad tyvar - ASSERT( not (null stmts) ) - tcAddSrcLoc src_loc $ - - newTyVarTy (mkArrowKind boxedTypeKind boxedTypeKind) `thenNF_Tc` \ m -> - newTyVarTy boxedTypeKind `thenNF_Tc` \ elt_ty -> - unifyTauTy res_ty (mkAppTy m elt_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_` returnTc () - _ -> returnTc ()) `thenTc_` - - tcStmts do_or_lc (mkAppTy m) stmts elt_ty `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, - -- 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. - -- - tcLookupValueByKey returnMClassOpKey `thenNF_Tc` \ return_sel_id -> - tcLookupValueByKey thenMClassOpKey `thenNF_Tc` \ then_sel_id -> - tcLookupValueByKey failMClassOpKey `thenNF_Tc` \ fail_sel_id -> - newMethod DoOrigin return_sel_id [m] `thenNF_Tc` \ (return_lie, return_id) -> - newMethod DoOrigin then_sel_id [m] `thenNF_Tc` \ (then_lie, then_id) -> - newMethod DoOrigin fail_sel_id [m] `thenNF_Tc` \ (fail_lie, fail_id) -> - let - monad_lie = then_lie `plusLIE` return_lie `plusLIE` fail_lie - in - returnTc (HsDoOut do_or_lc stmts' return_id then_id fail_id res_ty src_loc, - stmts_lie `plusLIE` monad_lie) +#ifndef GHCI + tc_local_id id th_bind_lvl proc_lvl -- Non-TH case + = checkProcLevel id proc_lvl `thenM_` + loop (HsVar id) (idType id) + +#else /* GHCI and TH is on */ + tc_local_id id th_bind_lvl proc_lvl -- TH case + = checkProcLevel id proc_lvl `thenM_` + + -- Check for cross-stage lifting + getStage `thenM` \ use_stage -> + case use_stage of + Brack use_lvl ps_var lie_var + | use_lvl > th_bind_lvl + -> -- E.g. \x -> [| h x |] + -- We must behave as if the reference to x was + + -- h $(lift x) + -- We use 'x' itself as the splice proxy, used by + -- the desugarer to stitch it all back together. + -- If 'x' occurs many times we may get many identical + -- bindings of the same splice proxy, but that doesn't + -- matter, although it's a mite untidy. + let + id_ty = idType id + in + checkTc (isTauTy id_ty) (polySpliceErr id) `thenM_` + -- If x is polymorphic, its occurrence sites might + -- have different instantiations, so we can't use plain + -- 'x' as the splice proxy name. I don't know how to + -- solve this, and it's probably unimportant, so I'm + -- just going to flag an error for now + + setLIEVar lie_var ( + newMethodFromName orig id_ty DsMeta.liftName `thenM` \ lift -> + -- Put the 'lift' constraint into the right LIE + + -- Update the pending splices + readMutVar ps_var `thenM` \ ps -> + writeMutVar ps_var ((name, nlHsApp (nlHsVar lift) (nlHsVar id)) : ps) `thenM_` + + returnM (HsVar id, id_ty)) + + other -> + checkWellStaged (quotes (ppr id)) th_bind_lvl use_stage `thenM_` + loop (HsVar id) (idType id) +#endif /* GHCI */ + + loop (HsVar fun_id) fun_ty + | want_method_inst fun_ty + = tcInstType VanillaTv fun_ty `thenM` \ (tyvars, theta, tau) -> + newMethodWithGivenTy orig fun_id + (mkTyVarTys tyvars) theta tau `thenM` \ meth_id -> + loop (HsVar meth_id) tau + + loop fun fun_ty + | isSigmaTy fun_ty + = tcInstCall orig fun_ty `thenM` \ (inst_fn, tau) -> + loop (inst_fn <$> fun) tau + + | otherwise + = returnM (fun, fun_ty) + + -- Hack Alert (want_method_inst)! + -- If f :: (%x :: T) => Int -> Int + -- Then if we have two separate calls, (f 3, f 4), we cannot + -- make a method constraint that then gets shared, thus: + -- let m = f %x in (m 3, m 4) + -- because that loses the linearity of the constraint. + -- The simplest thing to do is never to construct a method constraint + -- in the first place that has a linear implicit parameter in it. + want_method_inst fun_ty + | opt_NoMethodSharing = False + | otherwise = case tcSplitSigmaTy fun_ty of + (_,[],_) -> False -- Not overloaded + (_,theta,_) -> not (any isLinearPred theta) + + + -- We treat data constructors differently, because we have to generate + -- constraints for their silly theta, which no longer appears in + -- the type of dataConWrapId (see note on "stupid context" in DataCon.lhs + -- It's dual to TcPat.tcConstructor + inst_data_con data_con + = tcInstDataCon orig data_con `thenM` \ (ty_args, ex_dicts, arg_tys, result_ty, _) -> + extendLIEs ex_dicts `thenM_` + getSrcSpanM `thenM` \ loc -> + returnM (unLoc (mkHsDictApp (mkHsTyApp (L loc (HsVar (dataConWrapId data_con))) ty_args) + (map instToId ex_dicts)), + mkFunTys arg_tys result_ty) + -- ToDo: nasty loc/unloc stuff here + + orig = OccurrenceOf name \end{code} - %************************************************************************ %* * \subsection{Record bindings} @@ -984,180 +847,178 @@ 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 -- Expected type of whole record - -> RenamedRecordBinds - -> TcM s (TcRecordBinds, LIE) + :: TyCon -- Type constructor for the record + -> [TcType] -- Args of this type constructor + -> HsRecordBinds Name + -> TcM (HsRecordBinds TcId) -tcRecordBinds expected_record_ty rbinds - = mapAndUnzipTc do_bind rbinds `thenTc` \ (rbinds', lies) -> - returnTc (rbinds', plusLIEs lies) +tcRecordBinds tycon ty_args rbinds + = mappM do_bind rbinds where - do_bind (field_label, rhs, pun_flag) - = tcLookupValue field_label `thenNF_Tc` \ sel_id -> + tenv = mkTopTyVarSubst (tyConTyVars tycon) ty_args + + do_bind (L loc field_lbl_name, rhs) + = addErrCtxt (fieldCtxt field_lbl_name) $ + tcLookupId field_lbl_name `thenM` \ 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) -> + tcCheckSigma rhs field_ty `thenM` \ rhs' -> - -- 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 ((sel_id, rhs', pun_flag), lie) + returnM (L loc sel_id, rhs') badFields rbinds data_con - = [field_name | (field_name, _, _) <- rbinds, - not (field_name `elem` field_names) - ] + = filter (not . (`elem` field_names)) (recBindFields rbinds) where field_names = map fieldLabelName (dataConFieldLabels data_con) -missingStrictFields rbinds data_con - = [ fn | fn <- strict_field_names, - not (fn `elem` field_names_used) - ] - where - field_names_used = [ field_name | (field_name, _, _) <- rbinds ] - strict_field_names = mapMaybe isStrict field_info - - isStrict (fl, MarkedStrict) = Just (fieldLabelName fl) - isStrict _ = Nothing +checkMissingFields :: DataCon -> HsRecordBinds Name -> TcM () +checkMissingFields data_con rbinds + | null field_labels -- Not declared as a record; + -- But C{} is still valid if no strict fields + = if any isMarkedStrict field_strs then + -- Illegal if any arg is strict + addErrTc (missingStrictFields data_con []) + else + returnM () + + | otherwise -- A record + = checkM (null missing_s_fields) + (addErrTc (missingStrictFields data_con missing_s_fields)) `thenM_` - field_info = zip (dataConFieldLabels data_con) - (dataConStrictMarks data_con) + doptM Opt_WarnMissingFields `thenM` \ warn -> + checkM (not (warn && notNull missing_ns_fields)) + (warnTc True (missingFields data_con missing_ns_fields)) -missingFields rbinds data_con - = [ fn | fn <- non_strict_field_names, not (fn `elem` field_names_used) ] where - field_names_used = [ field_name | (field_name, _, _) <- rbinds ] - - -- missing strict fields have already been flagged as - -- being so, so leave them out here. - non_strict_field_names = mapMaybe isn'tStrict field_info - - isn'tStrict (fl, MarkedStrict) = Nothing - isn'tStrict (fl, _) = Just (fieldLabelName fl) - - field_info = zip (dataConFieldLabels data_con) - (dataConStrictMarks data_con) - + missing_s_fields + = [ fl | (fl, str) <- field_info, + isMarkedStrict str, + not (fieldLabelName fl `elem` field_names_used) + ] + missing_ns_fields + = [ fl | (fl, str) <- field_info, + not (isMarkedStrict str), + not (fieldLabelName fl `elem` field_names_used) + ] + + field_names_used = recBindFields rbinds + field_labels = dataConFieldLabels data_con + + field_info = zipEqual "missingFields" + field_labels + field_strs + + field_strs = dataConStrictMarks data_con \end{code} %************************************************************************ %* * -\subsection{@tcMonoExprs@ typechecks a {\em list} of expressions} +\subsection{@tcCheckRhos@ typechecks a {\em list} of expressions} %* * %************************************************************************ \begin{code} -tcMonoExprs :: [RenamedHsExpr] -> [TcType] -> TcM s ([TcExpr], LIE) +tcCheckRhos :: [LHsExpr Name] -> [TcType] -> TcM [LHsExpr TcId] -tcMonoExprs [] [] = returnTc ([], emptyLIE) -tcMonoExprs (expr:exprs) (ty:tys) - = tcMonoExpr expr ty `thenTc` \ (expr', lie1) -> - tcMonoExprs exprs tys `thenTc` \ (exprs', lie2) -> - returnTc (expr':exprs', lie1 `plusLIE` lie2) +tcCheckRhos [] [] = returnM [] +tcCheckRhos (expr:exprs) (ty:tys) + = tcCheckRho expr ty `thenM` \ expr' -> + tcCheckRhos exprs tys `thenM` \ exprs' -> + returnM (expr':exprs') \end{code} -% ================================================= +%************************************************************************ +%* * +\subsection{Literals} +%* * +%************************************************************************ -Errors and contexts -~~~~~~~~~~~~~~~~~~~ +Overloaded literals. -Mini-utils: \begin{code} -pp_nest_hang :: String -> SDoc -> SDoc -pp_nest_hang lbl stuff = nest 2 (hang (text lbl) 4 stuff) +tcLit :: HsLit -> Expected TcRhoType -> TcM (HsExpr TcId) +tcLit lit res_ty + = zapExpectedTo res_ty (hsLitType lit) `thenM_` + returnM (HsLit lit) \end{code} + +%************************************************************************ +%* * +\subsection{Errors and contexts} +%* * +%************************************************************************ + Boring and alphabetical: \begin{code} arithSeqCtxt expr = hang (ptext SLIT("In an arithmetic sequence:")) 4 (ppr expr) +parrSeqCtxt expr + = hang (ptext SLIT("In a parallel array sequence:")) 4 (ppr expr) + caseCtxt expr = hang (ptext SLIT("In the case expression:")) 4 (ppr expr) caseScrutCtxt expr = hang (ptext SLIT("In the scrutinee of a case expression:")) 4 (ppr expr) -exprSigCtxt expr - = hang (ptext SLIT("In an expression with a type signature:")) - 4 (ppr expr) - -listCtxt expr - = hang (ptext SLIT("In the list element:")) 4 (ppr expr) - -predCtxt expr - = hang (ptext SLIT("In the predicate expression:")) 4 (ppr expr) - -sectionRAppCtxt expr - = hang (ptext SLIT("In the right section:")) 4 (ppr expr) +exprCtxt expr + = hang (ptext SLIT("In the expression:")) 4 (ppr expr) -sectionLAppCtxt expr - = hang (ptext SLIT("In the left section:")) 4 (ppr expr) +fieldCtxt field_name + = ptext SLIT("In the") <+> quotes (ppr field_name) <+> ptext SLIT("field of a record") funAppCtxt fun arg arg_no = hang (hsep [ ptext SLIT("In the"), speakNth arg_no, ptext SLIT("argument of"), quotes (ppr fun) <> text ", namely"]) 4 (quotes (ppr arg)) -wrongArgsCtxt too_many_or_few fun args - = 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)) - where - the_app = foldl HsApp fun args -- Used in error messages +listCtxt expr + = hang (ptext SLIT("In the list element:")) 4 (ppr expr) + +parrCtxt expr + = hang (ptext SLIT("In the parallel array element:")) 4 (ppr expr) + +predCtxt expr + = hang (ptext SLIT("In the predicate expression:")) 4 (ppr expr) appCtxt fun args = 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 + the_app = foldl mkHsApp fun args -- Used in error messages badFieldsUpd rbinds = hang (ptext SLIT("No constructor has all these fields:")) - 4 (pprQuotedList fields) - where - fields = [field | (field, _, _) <- rbinds] + 4 (pprQuotedList (recBindFields rbinds)) recordUpdCtxt expr = ptext SLIT("In the record update:") <+> ppr expr recordConCtxt expr = ptext SLIT("In the record construction:") <+> ppr expr @@ -1165,22 +1026,33 @@ recordConCtxt expr = ptext SLIT("In the record construction:") <+> ppr expr notSelector field = hsep [quotes (ppr field), ptext SLIT("is not a record selector")] -illegalCcallTyErr isArg ty - = hang (hsep [ptext SLIT("Unacceptable"), arg_or_res, ptext SLIT("type in _ccall_ or _casm_:")]) - 4 (hsep [ppr ty]) +missingStrictFields :: DataCon -> [FieldLabel] -> SDoc +missingStrictFields con fields + = header <> rest where - arg_or_res - | isArg = ptext SLIT("argument") - | otherwise = ptext SLIT("result") - + rest | null fields = empty -- Happens for non-record constructors + -- with strict fields + | otherwise = colon <+> pprWithCommas ppr fields + + header = ptext SLIT("Constructor") <+> quotes (ppr con) <+> + ptext SLIT("does not have the required strict field(s)") + +missingFields :: DataCon -> [FieldLabel] -> SDoc +missingFields con fields + = ptext SLIT("Fields of") <+> quotes (ppr con) <+> ptext SLIT("not initialised:") + <+> pprWithCommas ppr fields -missingStrictFieldCon :: Name -> Name -> SDoc -missingStrictFieldCon con field - = hsep [ptext SLIT("Constructor") <+> quotes (ppr con), - ptext SLIT("does not have the required strict field"), quotes (ppr field)] +wrongArgsCtxt too_many_or_few fun args + = 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)) + where + the_app = foldl mkHsApp fun args -- Used in error messages -missingFieldCon :: Name -> Name -> SDoc -missingFieldCon con field - = hsep [ptext SLIT("Field") <+> quotes (ppr field), - ptext SLIT("is not initialised")] +#ifdef GHCI +polySpliceErr :: Id -> SDoc +polySpliceErr id + = ptext SLIT("Can't splice the polymorphic local variable") <+> quotes (ppr id) +#endif \end{code}