X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Fcompiler%2Ftypecheck%2FTcExpr.lhs;h=a26a106e8461af01bbb60f405627e50128404a36;hb=ca49225cd41123ab6ce229040a93cc4b993b190a;hp=c5e33f3e3fe34359c3b0ce0095333b441de46884;hpb=b2f644fa8edcf8697640c9228089b39030b8b362;p=ghc-hetmet.git diff --git a/ghc/compiler/typecheck/TcExpr.lhs b/ghc/compiler/typecheck/TcExpr.lhs index c5e33f3..a26a106 100644 --- a/ghc/compiler/typecheck/TcExpr.lhs +++ b/ghc/compiler/typecheck/TcExpr.lhs @@ -4,71 +4,75 @@ \section[TcExpr]{Typecheck an expression} \begin{code} -module TcExpr ( tcExpr, tcMonoExpr, tcId ) where +module TcExpr ( tcCheckSigma, tcCheckRho, tcInferRho, + tcMonoExpr, tcExpr, tcSyntaxOp + ) where #include "HsVersions.h" -import HsSyn ( HsExpr(..), HsLit(..), ArithSeqInfo(..), - HsMatchContext(..), HsDoContext(..), - mkMonoBind +#ifdef GHCI /* Only if bootstrapped */ +import {-# SOURCE #-} TcSplice( tcSpliceExpr, tcBracket ) +import HsSyn ( nlHsVar ) +import Id ( Id ) +import Name ( isExternalName ) +import TcType ( isTauTy ) +import TcEnv ( checkWellStaged ) +import HsSyn ( nlHsApp ) +import qualified DsMeta +#endif + +import HsSyn ( HsExpr(..), LHsExpr, HsLit(..), ArithSeqInfo(..), recBindFields, + HsMatchContext(..), HsRecordBinds, mkHsApp ) +import TcHsSyn ( hsLitType, (<$>) ) +import TcRnMonad +import TcUnify ( Expected(..), tcInfer, zapExpectedType, zapExpectedTo, + tcSubExp, tcGen, tcSub, + unifyFunTys, zapToListTy, zapToTyConApp ) +import BasicTypes ( isMarkedStrict ) +import Inst ( tcOverloadedLit, newMethodFromName, newIPDict, + newDicts, newMethodWithGivenTy, tcInstStupidTheta, tcInstCall ) +import TcBinds ( tcLocalBinds ) +import TcEnv ( tcLookup, tcLookupId, + tcLookupDataCon, tcLookupGlobalId ) -import RnHsSyn ( RenamedHsExpr, RenamedRecordBinds ) -import TcHsSyn ( TcExpr, TcRecordBinds, simpleHsLitTy, mkHsDictApp, mkHsTyApp ) - -import TcMonad -import TcUnify ( tcSubExp, tcGen, (<$>), - unifyTauTy, unifyFunTy, unifyListTy, unifyPArrTy, - unifyTupleTy ) -import BasicTypes ( RecFlag(..), isMarkedStrict ) -import Inst ( InstOrigin(..), - LIE, mkLIE, emptyLIE, unitLIE, plusLIE, plusLIEs, - newOverloadedLit, newMethodFromName, newIPDict, - newDicts, newMethodWithGivenTy, - instToId, tcInstCall, tcInstDataCon - ) -import TcBinds ( tcBindsAndThen ) -import TcEnv ( tcLookupClass, tcLookupGlobalId, tcLookupGlobal_maybe, - tcLookupTyCon, tcLookupDataCon, tcLookupId - ) -import TcMatches ( tcMatchesCase, tcMatchLambda, tcStmts ) -import TcMonoType ( tcHsSigType, UserTypeCtxt(..) ) -import TcPat ( badFieldCon ) -import TcSimplify ( tcSimplifyIPs ) -import TcMType ( tcInstTyVars, tcInstType, newHoleTyVarTy, zapToType, - newTyVarTy, newTyVarTys, zonkTcType, readHoleResult ) -import TcType ( TcType, TcSigmaType, TcRhoType, TyVarDetails(VanillaTv), - tcSplitFunTys, tcSplitTyConApp, mkTyVarTys, - isSigmaTy, mkFunTy, mkAppTy, mkFunTys, - mkTyConApp, mkClassPred, tcFunArgTy, - tyVarsOfTypes, isLinearPred, - liftedTypeKind, openTypeKind, mkArrowKind, - tcSplitSigmaTy, tcTyConAppTyCon, - tidyOpenType - ) -import FieldLabel ( FieldLabel, fieldLabelName, fieldLabelType, fieldLabelTyCon ) -import Id ( idType, recordSelectorFieldLabel, isRecordSelector, isDataConWrapId_maybe ) -import DataCon ( dataConFieldLabels, dataConSig, - dataConStrictMarks +import TcArrows ( tcProc ) +import TcMatches ( tcMatchesCase, tcMatchLambda, tcDoStmts, tcThingWithSig, TcMatchCtxt(..) ) +import TcHsType ( tcHsSigType, UserTypeCtxt(..) ) +import TcPat ( badFieldCon, refineTyVars ) +import TcMType ( tcInstTyVars, tcInstType, newTyFlexiVarTy, zonkTcType ) +import TcType ( TcTyVar, TcType, TcSigmaType, TcRhoType, + tcSplitFunTys, mkTyVarTys, + isSigmaTy, mkFunTy, mkTyConApp, tyVarsOfTypes, isLinearPred, + tcSplitSigmaTy, tidyOpenType ) +import Kind ( openTypeKind, liftedTypeKind, argTypeKind ) + +import Id ( idType, recordSelectorFieldLabel, isRecordSelector, isNaughtyRecordSelector ) +import DataCon ( DataCon, dataConFieldLabels, dataConStrictMarks, + dataConWrapId, isVanillaDataCon, dataConTyVars, dataConOrigArgTys ) import Name ( Name ) -import TyCon ( TyCon, tyConTyVars, tyConTheta, isAlgTyCon, tyConDataCons ) -import Subst ( mkTopTyVarSubst, substTheta, substTy ) +import TyCon ( FieldLabel, tyConStupidTheta, tyConDataCons ) +import Type ( substTheta, substTy ) +import Var ( tyVarKind ) import VarSet ( emptyVarSet, elemVarSet ) -import TysWiredIn ( boolTy, mkListTy, mkPArrTy ) -import PrelNames ( cCallableClassName, - cReturnableClassName, - enumFromName, enumFromThenName, +import TysWiredIn ( boolTy, parrTyCon, tupleTyCon ) +import PrelNames ( enumFromName, enumFromThenName, enumFromToName, enumFromThenToName, - enumFromToPName, enumFromThenToPName, - ioTyConName + enumFromToPName, enumFromThenToPName, negateName ) -import ListSetOps ( minusList ) -import CmdLineOpts +import DynFlags +import StaticFlags ( opt_NoMethodSharing ) import HscTypes ( TyThing(..) ) - +import SrcLoc ( Located(..), unLoc, getLoc ) import Util +import ListSetOps ( assocMaybe ) +import Maybes ( catMaybes ) import Outputable import FastString + +#ifdef DEBUG +import TyCon ( tyConArity ) +#endif \end{code} %************************************************************************ @@ -78,53 +82,86 @@ import FastString %************************************************************************ \begin{code} -tcExpr :: RenamedHsExpr -- Expession to type check - -> TcSigmaType -- Expected type (could be a polytpye) - -> TcM (TcExpr, LIE) -- Generalised expr with expected type, and LIE +-- 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 -tcExpr expr expected_ty - = traceTc (text "tcExpr" <+> (ppr expected_ty $$ ppr expr)) `thenNF_Tc_` +tcCheckSigma expr expected_ty + = -- traceTc (text "tcExpr" <+> (ppr expected_ty $$ ppr expr)) `thenM_` tc_expr' expr expected_ty -tc_expr' expr expected_ty - | not (isSigmaTy expected_ty) -- Monomorphic case - = tcMonoExpr 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 <$> unLoc expr')) - | otherwise - = tcGen expected_ty emptyVarSet ( - tcMonoExpr expr - ) `thenTc` \ (gen_fn, expr', lie) -> - returnTc (gen_fn <$> expr', lie) +tc_expr' expr rho_ty -- Monomorphic case + = tcCheckRho expr rho_ty +\end{code} + +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} +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)) = setSrcSpan loc $ do + { (e,_,ty) <- tcId (OccurrenceOf name) name + ; return (L loc e, ty) } +tcInferRho expr = tcInfer (tcMonoExpr expr) + +tcSyntaxOp :: InstOrigin -> HsExpr Name -> TcType -> TcM (HsExpr TcId) +-- Typecheck a syntax operator, checking that it has the specified type +-- The operator is always a variable at this stage (i.e. renamer output) +tcSyntaxOp orig (HsVar op) ty = do { (expr', _, id_ty) <- tcId orig op + ; co_fn <- tcSub ty id_ty + ; returnM (co_fn <$> expr') } +tcSyntaxOp orig other ty = pprPanic "tcSyntaxOp" (ppr other) \end{code} + %************************************************************************ %* * -\subsection{The TAUT rules for variables} +\subsection{The TAUT rules for variables}TcExpr %* * %************************************************************************ \begin{code} -tcMonoExpr :: RenamedHsExpr -- Expession to type check - -> TcRhoType -- Expected type (could be a type variable) +tcMonoExpr :: LHsExpr Name -- Expession to type check + -> Expected TcRhoType -- Expected type (could be a type variable) -- Definitely no foralls at the top -- Can be a 'hole'. - -> TcM (TcExpr, LIE) + -> TcM (LHsExpr TcId) + +tcMonoExpr (L loc expr) res_ty + = setSrcSpan loc (do { expr' <- tcExpr expr res_ty + ; return (L loc expr') }) -tcMonoExpr (HsVar name) res_ty - = tcId name `thenNF_Tc` \ (expr', lie1, id_ty) -> - tcSubExp res_ty id_ty `thenTc` \ (co_fn, lie2) -> - returnTc (co_fn <$> expr', lie1 `plusLIE` lie2) +tcExpr :: HsExpr Name -> Expected TcRhoType -> TcM (HsExpr TcId) +tcExpr (HsVar name) res_ty + = do { (expr', _, id_ty) <- tcId (OccurrenceOf name) name + ; co_fn <- tcSubExp res_ty id_ty + ; returnM (co_fn <$> expr') } -tcMonoExpr (HsIPVar ip) res_ty +tcExpr (HsIPVar ip) res_ty = -- Implicit parameters must have a *tau-type* not a -- type scheme. We enforce this by creating a fresh -- type variable as its type. (Because res_ty may not -- be a tau-type.) - newTyVarTy openTypeKind `thenNF_Tc` \ ip_ty -> - newIPDict (IPOcc ip) ip ip_ty `thenNF_Tc` \ (ip', inst) -> - tcSubExp res_ty ip_ty `thenTc` \ (co_fn, lie) -> - returnNF_Tc (co_fn <$> HsIPVar ip', lie `plusLIE` unitLIE inst) + newTyFlexiVarTy 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} @@ -135,20 +172,13 @@ tcMonoExpr (HsIPVar ip) res_ty %************************************************************************ \begin{code} -tcMonoExpr in_expr@(ExprWithTySig expr poly_ty) res_ty - = tcHsSigType ExprSigCtxt poly_ty `thenTc` \ sig_tc_ty -> - tcExpr expr sig_tc_ty `thenTc` \ (expr', lie1) -> - - -- Must instantiate the outer for-alls of sig_tc_ty - -- else we risk instantiating a ? res_ty to a forall-type - -- which breaks the invariant that tcMonoExpr only returns phi-types - tcAddErrCtxt (exprSigCtxt in_expr) $ - tcInstCall SignatureOrigin sig_tc_ty `thenNF_Tc` \ (inst_fn, lie2, inst_sig_ty) -> - tcSubExp res_ty inst_sig_ty `thenTc` \ (co_fn, lie3) -> +tcExpr 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 <$> ExprWithTySigOut expr' poly_ty) - returnTc (co_fn <$> inst_fn expr', lie1 `plusLIE` lie2 `plusLIE` lie3) - -tcMonoExpr (HsType ty) res_ty +tcExpr (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) @@ -165,18 +195,35 @@ tcMonoExpr (HsType ty) res_ty %************************************************************************ \begin{code} -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 expr neg_name) res_ty - = tcMonoExpr (HsApp (HsVar neg_name) 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 +tcExpr (HsPar expr) res_ty = tcMonoExpr expr res_ty `thenM` \ expr' -> + returnM (HsPar expr') +tcExpr (HsSCC lbl expr) res_ty = tcMonoExpr expr res_ty `thenM` \ expr' -> + returnM (HsSCC lbl expr') +tcExpr (HsCoreAnn lbl expr) res_ty = tcMonoExpr expr res_ty `thenM` \ expr' -> -- hdaume: core annotation + returnM (HsCoreAnn lbl expr') + +tcExpr (HsLit lit) res_ty = tcLit lit res_ty + +tcExpr (HsOverLit lit) res_ty + = zapExpectedType res_ty liftedTypeKind `thenM` \ res_ty' -> + -- Overloaded literals must have liftedTypeKind, because + -- we're instantiating an overloaded function here, + -- whereas res_ty might be openTypeKind. This was a bug in 6.2.2 + tcOverloadedLit (LiteralOrigin lit) lit res_ty' `thenM` \ lit' -> + returnM (HsOverLit lit') + +tcExpr (NegApp expr neg_expr) res_ty + = do { res_ty' <- zapExpectedType res_ty liftedTypeKind + ; neg_expr' <- tcSyntaxOp (OccurrenceOf negateName) neg_expr + (mkFunTy res_ty' res_ty') + ; expr' <- tcCheckRho expr res_ty' + ; return (NegApp expr' neg_expr') } + +tcExpr (HsLam match) res_ty + = tcMatchLambda match res_ty `thenM` \ match' -> + returnM (HsLam match') + +tcExpr (HsApp e1 e2) res_ty = tcApp e1 [e2] res_ty \end{code} @@ -191,217 +238,138 @@ a type error will occur if they aren't. -- or just -- op e -tcMonoExpr in_expr@(SectionL arg1 op) res_ty - = tcExpr_id op `thenTc` \ (op', lie1, op_ty) -> - split_fun_ty op_ty 2 {- two args -} `thenTc` \ ([arg1_ty, arg2_ty], op_res_ty) -> - tcArg op (arg1, arg1_ty, 1) `thenTc` \ (arg1',lie2) -> - tcAddErrCtxt (exprCtxt in_expr) $ - tcSubExp res_ty (mkFunTy arg2_ty op_res_ty) `thenTc` \ (co_fn, lie3) -> - returnTc (co_fn <$> SectionL arg1' op', lie1 `plusLIE` lie2 `plusLIE` lie3) +tcExpr in_expr@(SectionL arg1 op) res_ty + = tcInferRho op `thenM` \ (op', op_ty) -> + unifyInfixTy op in_expr op_ty `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 arg2) res_ty - = tcExpr_id op `thenTc` \ (op', lie1, op_ty) -> - split_fun_ty op_ty 2 {- two args -} `thenTc` \ ([arg1_ty, arg2_ty], op_res_ty) -> - tcArg op (arg2, arg2_ty, 2) `thenTc` \ (arg2',lie2) -> - tcAddErrCtxt (exprCtxt in_expr) $ - tcSubExp res_ty (mkFunTy arg1_ty op_res_ty) `thenTc` \ (co_fn, lie3) -> - returnTc (co_fn <$> SectionR op' arg2', lie1 `plusLIE` lie2 `plusLIE` lie3) +tcExpr in_expr@(SectionR op arg2) res_ty + = tcInferRho op `thenM` \ (op', op_ty) -> + unifyInfixTy op in_expr op_ty `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') -- equivalent to (op e1) e2: -tcMonoExpr in_expr@(OpApp arg1 op fix arg2) res_ty - = tcExpr_id op `thenTc` \ (op', lie1, op_ty) -> - split_fun_ty op_ty 2 {- two args -} `thenTc` \ ([arg1_ty, arg2_ty], op_res_ty) -> - tcArg op (arg1, arg1_ty, 1) `thenTc` \ (arg1',lie2a) -> - tcArg op (arg2, arg2_ty, 2) `thenTc` \ (arg2',lie2b) -> - tcAddErrCtxt (exprCtxt in_expr) $ - tcSubExp res_ty op_res_ty `thenTc` \ (co_fn, lie3) -> - returnTc (OpApp arg1' op' fix arg2', - lie1 `plusLIE` lie2a `plusLIE` lie2b `plusLIE` lie3) +tcExpr in_expr@(OpApp arg1 op fix arg2) res_ty + = tcInferRho op `thenM` \ (op', op_ty) -> + unifyInfixTy op in_expr op_ty `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 (co_fn <$> OpApp arg1' op' fix arg2') \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. - \begin{code} -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 (unpackFS lbl) (Just arg)) - [mkClassPred cCallableClass [arg_ty]] `thenNF_Tc` \ arg_dicts -> - returnNF_Tc arg_dicts -- Actually a singleton bag +tcExpr (HsLet binds expr) res_ty + = do { (binds', expr') <- tcLocalBinds binds $ + tcMonoExpr expr res_ty + ; return (HsLet binds' expr') } - result_origin = CCallOrigin (unpackFS lbl) Nothing {- Not an arg -} - in - - -- Arguments - let tv_idxs | null args = [] - | otherwise = [1..length args] - in - newTyVarTys (length tv_idxs) openTypeKind `thenNF_Tc` \ arg_tys -> - tcMonoExprs args arg_tys `thenTc` \ (args', args_lie) -> - - -- 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 liftedTypeKind `thenNF_Tc` \ result_ty -> - let - io_result_ty = mkTyConApp ioTyCon [result_ty] - 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 -> - 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 lbl expr) res_ty - = tcMonoExpr expr res_ty `thenTc` \ (expr', lie) -> - returnTc (HsSCC lbl expr', lie) - -tcMonoExpr (HsLet binds expr) res_ty - = tcBindsAndThen - combiner - binds -- Bindings to check - tc_expr `thenTc` \ (expr', lie) -> - returnTc (expr', lie) - where - tc_expr = tcMonoExpr expr res_ty `thenTc` \ (expr', lie) -> - returnTc (expr', lie) - combiner is_rec bind expr = HsLet (mkMonoBind bind [] is_rec) expr - -tcMonoExpr in_expr@(HsCase scrut matches src_loc) res_ty - = tcAddSrcLoc src_loc $ - tcAddErrCtxt (caseCtxt in_expr) $ - - -- Typecheck the case alternatives first. +tcExpr in_expr@(HsCase scrut matches) exp_ty + = -- We used to typecheck the case alternatives first. -- The case patterns tend to give good type info to use -- when typechecking the scrutinee. For example -- 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. + -- But now, in the GADT world, we need to typecheck the scrutinee + -- first, to get type info that may be refined in the case alternatives + addErrCtxt (caseScrutCtxt scrut) + (tcInferRho scrut) `thenM` \ (scrut', scrut_ty) -> + + addErrCtxt (caseCtxt in_expr) $ + tcMatchesCase match_ctxt scrut_ty matches exp_ty `thenM` \ matches' -> + returnM (HsCase scrut' matches') + where + match_ctxt = MC { mc_what = CaseAlt, + mc_body = tcMonoExpr } + +tcExpr (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 - tcMatchesCase matches res_ty `thenTc` \ (scrut_ty, matches', lie2) -> + tcCheckRho b1 res_ty' `thenM` \ b1' -> + tcCheckRho b2 res_ty' `thenM` \ b2' -> + returnM (HsIf pred' b1' b2') - tcAddErrCtxt (caseScrutCtxt scrut) ( - tcMonoExpr scrut scrut_ty - ) `thenTc` \ (scrut',lie1) -> +tcExpr (HsDo do_or_lc stmts body _) res_ty + = tcDoStmts do_or_lc stmts body res_ty - returnTc (HsCase scrut' matches' src_loc, plusLIE lie1 lie2) +tcExpr 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 -tcMonoExpr (HsIf pred b1 b2 src_loc) res_ty - = tcAddSrcLoc src_loc $ - tcAddErrCtxt (predCtxt pred) ( - tcMonoExpr pred boolTy ) `thenTc` \ (pred',lie1) -> +tcExpr in_expr@(ExplicitPArr _ exprs) res_ty -- maybe empty + = do { [elt_ty] <- zapToTyConApp parrTyCon res_ty + ; exprs' <- mappM (tc_elt elt_ty) exprs + ; return (ExplicitPArr elt_ty exprs') } + where + tc_elt elt_ty expr + = addErrCtxt (parrCtxt expr) (tcCheckRho expr elt_ty) - zapToType res_ty `thenTc` \ res_ty' -> - -- C.f. the call to zapToType in TcMatches.tcMatches +tcExpr (ExplicitTuple exprs boxity) res_ty + = do { arg_tys <- zapToTyConApp (tupleTyCon boxity (length exprs)) res_ty + ; exprs' <- tcCheckRhos exprs arg_tys + ; return (ExplicitTuple exprs' boxity) } - 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} +tcExpr (HsProc pat cmd) res_ty + = tcProc pat cmd res_ty `thenM` \ (pat', cmd') -> + returnM (HsProc pat' cmd') -\begin{code} -tcMonoExpr expr@(HsDo do_or_lc stmts method_names _ src_loc) res_ty - = tcAddSrcLoc src_loc (tcDoStmts do_or_lc stmts method_names src_loc res_ty) +tcExpr e@(HsArrApp _ _ _ _ _) _ + = failWithTc (vcat [ptext SLIT("The arrow command"), nest 2 (ppr e), + ptext SLIT("was found where an expression was expected")]) + +tcExpr e@(HsArrForm _ _ _) _ + = failWithTc (vcat [ptext SLIT("The arrow command"), nest 2 (ppr e), + ptext SLIT("was found where an expression was expected")]) \end{code} +%************************************************************************ +%* * + Record construction and update +%* * +%************************************************************************ + \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 (ExplicitList elt_ty exprs', plusLIEs lies) - where - tc_elt elt_ty expr - = tcAddErrCtxt (listCtxt expr) $ - tcMonoExpr expr elt_ty +tcExpr expr@(RecordCon (L loc con_name) _ rbinds) res_ty + = addErrCtxt (recordConCtxt expr) $ + do { (con_expr, _, con_tau) <- setSrcSpan loc $ + tcId (OccurrenceOf con_name) con_name + ; data_con <- tcLookupDataCon con_name -tcMonoExpr in_expr@(ExplicitPArr _ exprs) res_ty -- maybe empty - = unifyPArrTy res_ty `thenTc` \ elt_ty -> - mapAndUnzipTc (tc_elt elt_ty) exprs `thenTc` \ (exprs', lies) -> - returnTc (ExplicitPArr elt_ty exprs', plusLIEs lies) - where - tc_elt elt_ty expr - = tcAddErrCtxt (parrCtxt expr) $ - tcMonoExpr expr elt_ty - -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' boxity, plusLIEs lies) - -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) = tcSplitFunTys con_tau - (tycon, ty_args) = tcSplitTyConApp record_ty - in - ASSERT( isAlgTyCon tycon ) - unifyTauTy res_ty record_ty `thenTc_` + ; let (arg_tys, record_ty) = tcSplitFunTys con_tau + flds_w_tys = zipEqual "tcExpr RecordCon" (dataConFieldLabels data_con) arg_tys - -- 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 data_con - in - if notNull 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 + -- Make the result type line up + ; zapExpectedTo res_ty record_ty -- Typecheck the record bindings - tcRecordBinds tycon ty_args rbinds `thenTc` \ (rbinds', rbinds_lie) -> + ; rbinds' <- tcRecordBinds data_con flds_w_tys rbinds - 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 && notNull 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 - returnTc (RecordConOut data_con con_expr rbinds', con_lie `plusLIE` rbinds_lie) + ; returnM (RecordCon (L loc (dataConWrapId data_con)) con_expr rbinds') } -- The main complication with RecordUpd is that we need to explicitly -- handle the *non-updated* fields. Consider: @@ -428,57 +396,56 @@ tcMonoExpr expr@(RecordCon con_name rbinds) res_ty -- its RHS is simply an error, so it doesn't impose any type constraints -- -- All this is done in STEP 4 below. +-- +-- Note about GADTs +-- ~~~~~~~~~~~~~~~~ +-- For record update we require that every constructor involved in the +-- update (i.e. that has all the specified fields) is "vanilla". I +-- don't know how to do the update otherwise. + -tcMonoExpr expr@(RecordUpd record_expr rbinds) res_ty - = tcAddErrCtxt (recordUpdCtxt expr) $ +tcExpr expr@(RecordUpd record_expr rbinds _ _) res_ty + = addErrCtxt (recordUpdCtxt expr) $ -- STEP 0 -- Check that the field names are really field names ASSERT( notNull rbinds ) let - field_names = [field_name | (field_name, _, _) <- rbinds] + field_names = map fst rbinds in - mapNF_Tc tcLookupGlobal_maybe 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 = [ 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 + bad_guys = [ setSrcSpan loc $ addErrTc (notSelector field_name) + | (L loc field_name, sel_id) <- field_names `zip` sel_ids, + not (isRecordSelector sel_id) -- Excludes class ops ] in - checkTcM (null bad_guys) (listNF_Tc bad_guys `thenNF_Tc_` failTc) `thenTc_` + 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 -- 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 - tycon_tyvars = tyConTyVars tycon -- The data cons use the same type vars + upd_field_lbls = recBindFields rbinds + sel_id : _ = sel_ids + (tycon, _) = recordSelectorFieldLabel sel_id -- We've failed already if + data_cons = tyConDataCons tycon -- it's not a field label + relevant_cons = filter is_relevant data_cons + is_relevant con = all (`elem` dataConFieldLabels con) upd_field_lbls in - tcInstTyVars VanillaTv tycon_tyvars `thenNF_Tc` \ (_, 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_` + checkTc (not (null relevant_cons)) + (badFieldsUpd rbinds) `thenM_` - -- STEP 3 - -- Typecheck the update bindings. - -- (Do this after checking for bad fields in case there's a field that - -- doesn't match the constructor.) - let - result_record_ty = mkTyConApp tycon result_inst_tys - in - unifyTauTy res_ty result_record_ty `thenTc_` - tcRecordBinds tycon result_inst_tys rbinds `thenTc` \ (rbinds', rbinds_lie) -> + -- Check that all relevant data cons are vanilla. Doing record updates on + -- GADTs and/or existentials is more than my tiny brain can cope with today + checkTc (all isVanillaDataCon relevant_cons) + (nonVanillaUpd tycon) `thenM_` -- STEP 4 -- Use the un-updated fields to find a vector of booleans saying @@ -487,29 +454,43 @@ 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'] - con_field_lbls_s = map dataConFieldLabels data_cons - -- A constructor is only relevant to this process if - -- it contains all the fields that are being updated - relevant_field_lbls_s = filter is_relevant con_field_lbls_s - is_relevant con_field_lbls = all (`elem` con_field_lbls) upd_field_lbls - - non_upd_field_lbls = concat relevant_field_lbls_s `minusList` upd_field_lbls - common_tyvars = tyVarsOfTypes (map fieldLabelType non_upd_field_lbls) + -- it contains *all* the fields that are being updated + con1 = head relevant_cons -- A representative constructor + con1_tyvars = dataConTyVars con1 + con1_fld_tys = dataConFieldLabels con1 `zip` dataConOrigArgTys con1 + common_tyvars = tyVarsOfTypes [ty | (fld,ty) <- con1_fld_tys + , not (fld `elem` upd_field_lbls) ] + + is_common_tv tv = tv `elemVarSet` common_tyvars + + mk_inst_ty tv result_inst_ty + | is_common_tv tv = returnM result_inst_ty -- Same as result type + | otherwise = newTyFlexiVarTy (tyVarKind tv) -- Fresh type, of correct kind + in + tcInstTyVars con1_tyvars `thenM` \ (_, result_inst_tys, inst_env) -> + zipWithM mk_inst_ty con1_tyvars result_inst_tys `thenM` \ inst_tys -> - mk_inst_ty (tyvar, result_inst_ty) - | tyvar `elemVarSet` common_tyvars = returnNF_Tc result_inst_ty -- Same as result type - | otherwise = newTyVarTy liftedTypeKind -- Fresh type + -- STEP 3 + -- Typecheck the update bindings. + -- (Do this after checking for bad fields in case there's a field that + -- doesn't match the constructor.) + let + result_record_ty = mkTyConApp tycon result_inst_tys + inst_fld_tys = [(fld, substTy inst_env ty) | (fld, ty) <- con1_fld_tys] in - mapNF_Tc mk_inst_ty (zip tycon_tyvars result_inst_tys) `thenNF_Tc` \ inst_tys -> + zapExpectedTo res_ty result_record_ty `thenM_` + tcRecordBinds con1 inst_fld_tys rbinds `thenM` \ rbinds' -> -- STEP 5 -- Typecheck the expression to be updated let - record_ty = mkTyConApp tycon inst_tys + record_ty = ASSERT( length inst_tys == tyConArity tycon ) + mkTyConApp tycon inst_tys + -- This is one place where the isVanilla check is important + -- So that inst_tys matches the tycon 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 @@ -517,121 +498,124 @@ tcMonoExpr expr@(RecordUpd record_expr rbinds) res_ty -- do pattern matching over the data cons. -- -- What dictionaries do we need? - -- We just take the context of the type constructor + -- We just take the context of the first data constructor + -- This isn't right, but I just can't bear to union up all the relevant ones let - theta' = substTheta inst_env (tyConTheta tycon) + theta' = substTheta inst_env (tyConStupidTheta tycon) in - newDicts RecordUpdOrigin theta' `thenNF_Tc` \ dicts -> + newDicts RecordUpdOrigin theta' `thenM` \ dicts -> + extendLIEs dicts `thenM_` -- Phew! - returnTc (RecordUpdOut record_expr' record_ty result_record_ty rbinds', - mkLIE dicts `plusLIE` record_lie `plusLIE` rbinds_lie) + returnM (RecordUpd record_expr' rbinds' record_ty result_record_ty) +\end{code} + + +%************************************************************************ +%* * + Arithmetic sequences e.g. [a,b..] + and their parallel-array counterparts e.g. [: a,b.. :] + +%* * +%************************************************************************ -tcMonoExpr (ArithSeqIn seq@(From expr)) res_ty - = unifyListTy res_ty `thenTc` \ elt_ty -> - tcMonoExpr expr elt_ty `thenTc` \ (expr', lie1) -> +\begin{code} +tcExpr (ArithSeq _ seq@(From expr)) res_ty + = zapToListTy res_ty `thenM` \ elt_ty -> + tcCheckRho expr elt_ty `thenM` \ expr' -> newMethodFromName (ArithSeqOrigin seq) - elt_ty enumFromName `thenNF_Tc` \ enum_from -> + elt_ty enumFromName `thenM` \ enum_from -> - returnTc (ArithSeqOut (HsVar (instToId enum_from)) (From expr'), - lie1 `plusLIE` unitLIE enum_from) + returnM (ArithSeq (HsVar enum_from) (From expr')) -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) -> +tcExpr in_expr@(ArithSeq _ 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 `thenNF_Tc` \ enum_from_then -> + elt_ty enumFromThenName `thenM` \ enum_from_then -> - returnTc (ArithSeqOut (HsVar (instToId enum_from_then)) - (FromThen expr1' expr2'), - lie1 `plusLIE` lie2 `plusLIE` unitLIE enum_from_then) + returnM (ArithSeq (HsVar enum_from_then) (FromThen expr1' expr2')) -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) -> + +tcExpr in_expr@(ArithSeq _ 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 `thenNF_Tc` \ enum_from_to -> - - returnTc (ArithSeqOut (HsVar (instToId enum_from_to)) - (FromTo expr1' expr2'), - 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) -> + elt_ty enumFromToName `thenM` \ enum_from_to -> + + returnM (ArithSeq (HsVar enum_from_to) (FromTo expr1' expr2')) + +tcExpr in_expr@(ArithSeq _ 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 `thenNF_Tc` \ eft -> + elt_ty enumFromThenToName `thenM` \ eft -> - returnTc (ArithSeqOut (HsVar (instToId eft)) - (FromThenTo expr1' expr2' expr3'), - lie1 `plusLIE` lie2 `plusLIE` lie3 `plusLIE` unitLIE eft) + returnM (ArithSeq (HsVar eft) (FromThenTo expr1' expr2' expr3')) -tcMonoExpr in_expr@(PArrSeqIn seq@(FromTo expr1 expr2)) res_ty - = tcAddErrCtxt (parrSeqCtxt in_expr) $ - unifyPArrTy res_ty `thenTc` \ elt_ty -> - tcMonoExpr expr1 elt_ty `thenTc` \ (expr1',lie1) -> - tcMonoExpr expr2 elt_ty `thenTc` \ (expr2',lie2) -> +tcExpr in_expr@(PArrSeq _ seq@(FromTo expr1 expr2)) res_ty + = addErrCtxt (parrSeqCtxt in_expr) $ + zapToTyConApp parrTyCon res_ty `thenM` \ [elt_ty] -> + tcCheckRho expr1 elt_ty `thenM` \ expr1' -> + tcCheckRho expr2 elt_ty `thenM` \ expr2' -> newMethodFromName (PArrSeqOrigin seq) - elt_ty enumFromToPName `thenNF_Tc` \ enum_from_to -> - - returnTc (PArrSeqOut (HsVar (instToId enum_from_to)) - (FromTo expr1' expr2'), - lie1 `plusLIE` lie2 `plusLIE` unitLIE enum_from_to) - -tcMonoExpr in_expr@(PArrSeqIn seq@(FromThenTo expr1 expr2 expr3)) res_ty - = tcAddErrCtxt (parrSeqCtxt in_expr) $ - unifyPArrTy 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) -> + elt_ty enumFromToPName `thenM` \ enum_from_to -> + + returnM (PArrSeq (HsVar enum_from_to) (FromTo expr1' expr2')) + +tcExpr in_expr@(PArrSeq _ seq@(FromThenTo expr1 expr2 expr3)) res_ty + = addErrCtxt (parrSeqCtxt in_expr) $ + zapToTyConApp parrTyCon 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 `thenNF_Tc` \ eft -> + elt_ty enumFromThenToPName `thenM` \ eft -> - returnTc (PArrSeqOut (HsVar (instToId eft)) - (FromThenTo expr1' expr2' expr3'), - lie1 `plusLIE` lie2 `plusLIE` lie3 `plusLIE` unitLIE eft) + returnM (PArrSeq (HsVar eft) (FromThenTo expr1' expr2' expr3')) -tcMonoExpr (PArrSeqIn _) _ +tcExpr (PArrSeq _ _) _ = panic "TcExpr.tcMonoExpr: Infinite parallel array!" -- the parser shouldn't have generated it and the renamer shouldn't have -- let it through \end{code} + %************************************************************************ %* * -\subsection{Implicit Parameter bindings} + Template Haskell %* * %************************************************************************ \begin{code} -tcMonoExpr (HsWith expr binds is_with) res_ty - = tcMonoExpr expr res_ty `thenTc` \ (expr', expr_lie) -> - mapAndUnzip3Tc tcIPBind binds `thenTc` \ (avail_ips, binds', bind_lies) -> +#ifdef GHCI /* Only if bootstrapped */ + -- Rename excludes these cases otherwise +tcExpr (HsSpliceE splice) res_ty = tcSpliceExpr splice res_ty +tcExpr (HsBracket brack) res_ty = do { e <- tcBracket brack res_ty + ; return (unLoc e) } +#endif /* GHCI */ +\end{code} - -- If the binding binds ?x = E, we must now - -- discharge any ?x constraints in expr_lie - tcSimplifyIPs avail_ips expr_lie `thenTc` \ (expr_lie', dict_binds) -> - let - expr'' = HsLet (mkMonoBind dict_binds [] Recursive) expr' - in - returnTc (HsWith expr'' binds' is_with, expr_lie' `plusLIE` plusLIEs bind_lies) - -tcIPBind (ip, expr) - = newTyVarTy openTypeKind `thenTc` \ ty -> - tcGetSrcLoc `thenTc` \ loc -> - newIPDict (IPBind ip) ip ty `thenNF_Tc` \ (ip', ip_inst) -> - tcMonoExpr expr ty `thenTc` \ (expr', lie) -> - returnTc (ip_inst, (ip', expr'), lie) + +%************************************************************************ +%* * + Catch-all +%* * +%************************************************************************ + +\begin{code} +tcExpr other _ = pprPanic "tcMonoExpr" (ppr other) \end{code} + %************************************************************************ %* * \subsection{@tcApp@ typchecks an application} @@ -640,44 +624,112 @@ tcIPBind (ip, expr) \begin{code} -tcApp :: RenamedHsExpr -> [RenamedHsExpr] -- Function and args - -> TcType -- Expected result type of application - -> TcM (TcExpr, LIE) -- Translated fun and args +tcApp :: LHsExpr Name -> [LHsExpr Name] -- Function and args + -> Expected TcRhoType -- Expected result type of application + -> TcM (HsExpr TcId) -- Translated fun and args -tcApp (HsApp e1 e2) args res_ty +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) -> - - tcAddErrCtxt (wrongArgsCtxt "too many" fun args) ( - traceTc (text "tcApp" <+> (ppr fun $$ ppr fun_ty)) `thenNF_Tc_` - split_fun_ty fun_ty (length args) - ) `thenTc` \ (expected_arg_tys, actual_result_ty) -> - - -- Now typecheck the args - mapAndUnzipTc (tcArg fun) - (zip3 args expected_arg_tys [1..]) `thenTc` \ (args', lie_args_s) -> - - -- Unify with expected result after type-checking the args - -- so that the info from args percolates to actual_result_ty. - -- This is when we might detect a too-few args situation. - -- (One can think of cases when the opposite order would give - -- a better error message.) - tcAddErrCtxtM (checkArgsCtxt fun args res_ty actual_result_ty) - (tcSubExp res_ty actual_result_ty) `thenTc` \ (co_fn, lie_res) -> - - returnTc (co_fn <$> foldl HsApp fun' args', - lie_res `plusLIE` lie_fun `plusLIE` plusLIEs lie_args_s) - + = do { let n_args = length args + ; (fun', fun_tvs, fun_tau) <- tcFun fun -- Type-check the function + + -- Extract its argument types + ; (expected_arg_tys, actual_res_ty) + <- do { traceTc (text "tcApp" <+> (ppr fun $$ ppr fun_tau)) + ; let msg = sep [ptext SLIT("The function") <+> quotes (ppr fun), + ptext SLIT("is applied to") + <+> speakN n_args <+> ptext SLIT("arguments")] + ; unifyFunTys msg n_args fun_tau } + + ; case res_ty of + Check _ -> do -- Connect to result type first + -- See Note [Push result type in] + { co_fn <- tcResult fun args res_ty actual_res_ty + ; the_app' <- tcArgs fun fun' args expected_arg_tys + ; traceTc (text "tcApp: check" <+> vcat [ppr fun <+> ppr args, + ppr the_app', ppr actual_res_ty]) + ; returnM (co_fn <$> the_app') } + + Infer _ -> do -- Type check args first, then + -- refine result type, then do tcResult + { the_app' <- tcArgs fun fun' args expected_arg_tys + ; subst <- refineTyVars fun_tvs + ; let actual_res_ty' = substTy subst actual_res_ty + ; co_fn <- tcResult fun args res_ty actual_res_ty' + ; traceTc (text "tcApp: infer" <+> vcat [ppr fun <+> ppr args, ppr the_app', + ppr actual_res_ty, ppr actual_res_ty']) + ; returnM (co_fn <$> the_app') } + } + +-- Note [Push result type in] +-- +-- 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_res_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.] + +---------------- +tcFun :: LHsExpr Name -> TcM (LHsExpr TcId, [TcTyVar], TcRhoType) +-- Instantiate the function, returning the type variables used +-- If the function isn't simple, infer its type, and return no +-- type variables +tcFun (L loc (HsVar f)) = setSrcSpan loc $ do + { (fun', tvs, fun_tau) <- tcId (OccurrenceOf f) f + ; return (L loc fun', tvs, fun_tau) } +tcFun fun = do { (fun', fun_tau) <- tcInfer (tcMonoExpr fun) + ; return (fun', [], fun_tau) } + +---------------- +tcArgs :: LHsExpr Name -- The function (for error messages) + -> LHsExpr TcId -- The function (to build into result) + -> [LHsExpr Name] -> [TcSigmaType] -- Actual arguments and expected arg types + -> TcM (HsExpr TcId) -- Resulting application + +tcArgs fun fun' args expected_arg_tys + = do { args' <- mappM (tcArg fun) (zip3 args expected_arg_tys [1..]) + ; return (unLoc (foldl mkHsApp fun' args')) } + +tcArg :: LHsExpr Name -- The function (for error messages) + -> (LHsExpr Name, TcSigmaType, Int) -- Actual argument and expected arg type + -> TcM (LHsExpr TcId) -- Resulting argument +tcArg fun (arg, ty, arg_no) = addErrCtxt (funAppCtxt fun arg arg_no) + (tcCheckSigma arg ty) + +---------------- +tcResult fun args res_ty actual_res_ty + = addErrCtxtM (checkArgsCtxt fun args res_ty actual_res_ty) + (tcSubExp res_ty actual_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 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 (Infer _) actual_res_ty tidy_env + = return (tidy_env, ptext SLIT("Urk infer")) + +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' @@ -691,32 +743,21 @@ checkArgsCtxt fun args expected_res_ty actual_res_ty tidy_env | len_exp_args > len_act_args = wrongArgsCtxt "too many" fun args | otherwise = appCtxt fun args in - returnNF_Tc (env2, message) - - -split_fun_ty :: TcType -- 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) - -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) -\end{code} - -\begin{code} -tcArg :: RenamedHsExpr -- The function (for error messages) - -> (RenamedHsExpr, TcSigmaType, 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) $ - tcExpr arg expected_arg_ty + returnM (env2, message) + +---------------- +unifyInfixTy :: LHsExpr Name -> HsExpr Name -> TcType + -> TcM ([TcType], TcType) +-- This wrapper just prepares the error message for unifyFunTys +unifyInfixTy op expr op_ty + = unifyFunTys msg 2 op_ty + where + msg = sep [herald <+> quotes (ppr expr), + ptext SLIT("requires") <+> quotes (ppr op) + <+> ptext SLIT("to take two arguments")] + herald = case expr of + OpApp _ _ _ _ -> ptext SLIT("The infix expression") + other -> ptext SLIT("The operator section") \end{code} @@ -749,37 +790,109 @@ This gets a bit less sharing, but b) perhaps fewer separated lambdas \begin{code} -tcId :: Name -> NF_TcM (TcExpr, LIE, TcType) -tcId name -- Look up the Id and instantiate its type - = tcLookupId name `thenNF_Tc` \ id -> - case isDataConWrapId_maybe id of - Nothing -> loop (HsVar id) emptyLIE (idType id) - Just data_con -> inst_data_con id data_con +tcId :: InstOrigin -> Name -> TcM (HsExpr TcId, [TcTyVar], TcRhoType) + -- Return the type variables at which the function + -- is instantiated, as well as the translated variable and its type + +tcId orig id_name -- Look up the Id and instantiate its type + = tcLookup id_name `thenM` \ thing -> + case thing of { + AGlobal (ADataCon con) -- Similar, but instantiate the stupid theta too + -> do { (expr, tvs, tau) <- instantiate (dataConWrapId con) + ; tcInstStupidTheta con (mkTyVarTys tvs) + -- Remember to chuck in the constraints from the "silly context" + ; return (expr, tvs, tau) } + + ; AGlobal (AnId id) | isNaughtyRecordSelector id + -> failWithTc (naughtyRecordSel id) + ; AGlobal (AnId id) -> instantiate id + -- A global cannot possibly be ill-staged + -- nor does it need the 'lifting' treatment + + ; ATcId id th_level -> tc_local_id id th_level + + ; other -> failWithTc (ppr other <+> ptext SLIT("used where a value identifer was expected")) + } where - orig = OccurrenceOf name - loop (HsVar fun_id) lie fun_ty +#ifndef GHCI + tc_local_id id th_bind_lvl -- Non-TH case + = instantiate id + +#else /* GHCI and TH is on */ + tc_local_id id th_bind_lvl -- TH case + = -- 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 + -> if isExternalName id_name then + -- Top-level identifiers in this module, + -- (which have External Names) + -- are just like the imported case: + -- no need for the 'lifting' treatment + -- E.g. this is fine: + -- f x = x + -- g y = [| f 3 |] + -- But we do need to put f into the keep-alive + -- set, because after desugaring the code will + -- only mention f's *name*, not f itself. + keepAliveTc id_name `thenM_` + instantiate id + + else -- Nested identifiers, such as 'x' in + -- E.g. \x -> [| h x |] + -- We must behave as if the reference to x was + -- h $(lift x) + -- We use 'x' itself as the splice proxy, used by + -- the desugarer to stitch it all back together. + -- If 'x' occurs many times we may get many identical + -- bindings of the same splice proxy, but that doesn't + -- matter, although it's a mite untidy. + let + id_ty = idType id + in + checkTc (isTauTy id_ty) (polySpliceErr id) `thenM_` + -- If x is polymorphic, its occurrence sites might + -- have different instantiations, so we can't use plain + -- 'x' as the splice proxy name. I don't know how to + -- solve this, and it's probably unimportant, so I'm + -- just going to flag an error for now + + setLIEVar lie_var ( + newMethodFromName orig id_ty DsMeta.liftName `thenM` \ lift -> + -- Put the 'lift' constraint into the right LIE + + -- Update the pending splices + readMutVar ps_var `thenM` \ ps -> + writeMutVar ps_var ((id_name, nlHsApp (nlHsVar lift) (nlHsVar id)) : ps) `thenM_` + + returnM (HsVar id, [], id_ty)) + + other -> + checkWellStaged (quotes (ppr id)) th_bind_lvl use_stage `thenM_` + instantiate id +#endif /* GHCI */ + + instantiate :: TcId -> TcM (HsExpr TcId, [TcTyVar], TcRhoType) + instantiate fun_id = loop (HsVar fun_id) [] (idType fun_id) + + loop (HsVar fun_id) tvs fun_ty | want_method_inst fun_ty - = tcInstType VanillaTv fun_ty `thenNF_Tc` \ (tyvars, theta, tau) -> + = tcInstType fun_ty `thenM` \ (tyvars, theta, tau) -> newMethodWithGivenTy orig fun_id - (mkTyVarTys tyvars) theta tau `thenNF_Tc` \ meth -> - loop (HsVar (instToId meth)) - (unitLIE meth `plusLIE` lie) tau + (mkTyVarTys tyvars) theta tau `thenM` \ meth_id -> + loop (HsVar meth_id) (tvs ++ tyvars) tau - loop fun lie fun_ty + loop fun tvs fun_ty | isSigmaTy fun_ty - = tcInstCall orig fun_ty `thenNF_Tc` \ (inst_fn, inst_lie, tau) -> - loop (inst_fn fun) (inst_lie `plusLIE` lie) tau + = tcInstCall orig fun_ty `thenM` \ (inst_fn, new_tvs, tau) -> + loop (inst_fn <$> fun) (tvs ++ new_tvs) tau | otherwise - = returnNF_Tc (fun, lie, fun_ty) + = returnM (fun, tvs, fun_ty) - want_method_inst fun_ty - | opt_NoMethodSharing = False - | otherwise = case tcSplitSigmaTy fun_ty of - (_,[],_) -> False -- Not overloaded - (_,theta,_) -> not (any isLinearPred theta) - -- This is a slight hack. + -- 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: @@ -787,81 +900,13 @@ tcId name -- Look up the Id and instantiate its type -- 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. - - -- We treat data constructors differently, because we have to generate - -- constraints for their silly theta, which no longer appears in - -- the type of dataConWrapId. It's dual to TcPat.tcConstructor - inst_data_con id data_con - = tcInstDataCon orig data_con `thenNF_Tc` \ (ty_args, ex_dicts, arg_tys, result_ty, stupid_lie, ex_lie, _) -> - returnNF_Tc (mkHsDictApp (mkHsTyApp (HsVar id) ty_args) ex_dicts, - stupid_lie `plusLIE` ex_lie, - mkFunTys arg_tys result_ty) -\end{code} - -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 HoleTyVarTy to pass in as the expected tyvar. - -\begin{code} -tcExpr_id :: RenamedHsExpr -> TcM (TcExpr, LIE, TcType) -tcExpr_id (HsVar name) = tcId name -tcExpr_id expr = newHoleTyVarTy `thenNF_Tc` \ id_ty -> - tcMonoExpr expr id_ty `thenTc` \ (expr', lie_id) -> - readHoleResult id_ty `thenTc` \ id_ty' -> - returnTc (expr', lie_id, id_ty') -\end{code} - - -%************************************************************************ -%* * -\subsection{@tcDoStmts@ typechecks a {\em list} of do statements} -%* * -%************************************************************************ - -\begin{code} -tcDoStmts PArrComp stmts method_names src_loc res_ty - = unifyPArrTy res_ty `thenTc` \elt_ty -> - tcStmts (DoCtxt PArrComp) - (mkPArrTy, elt_ty) stmts `thenTc` \(stmts', stmts_lie) -> - returnTc (HsDo PArrComp stmts' - [] -- Unused - res_ty src_loc, - stmts_lie) - -tcDoStmts ListComp stmts method_names src_loc res_ty - = unifyListTy res_ty `thenTc` \ elt_ty -> - tcStmts (DoCtxt ListComp) - (mkListTy, elt_ty) stmts `thenTc` \ (stmts', stmts_lie) -> - returnTc (HsDo ListComp stmts' - [] -- Unused - res_ty src_loc, - stmts_lie) - -tcDoStmts DoExpr stmts method_names src_loc res_ty - = newTyVarTy (mkArrowKind liftedTypeKind liftedTypeKind) `thenNF_Tc` \ tc_ty -> - newTyVarTy liftedTypeKind `thenNF_Tc` \ elt_ty -> - unifyTauTy res_ty (mkAppTy tc_ty elt_ty) `thenTc_` - - tcStmts (DoCtxt DoExpr) (mkAppTy tc_ty, elt_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, - -- 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. - -- - mapNF_Tc (newMethodFromName DoOrigin tc_ty) method_names `thenNF_Tc` \ insts -> - - returnTc (HsDo DoExpr stmts' - (map instToId insts) - res_ty src_loc, - stmts_lie `plusLIE` mkLIE insts) + want_method_inst fun_ty + | opt_NoMethodSharing = False + | otherwise = case tcSplitSigmaTy fun_ty of + (_,[],_) -> False -- Not overloaded + (_,theta,_) -> not (any isLinearPred theta) \end{code} - %************************************************************************ %* * \subsection{Record bindings} @@ -887,84 +932,81 @@ This extends OK when the field types are universally quantified. \begin{code} tcRecordBinds - :: TyCon -- Type constructor for the record - -> [TcType] -- Args of this type constructor - -> RenamedRecordBinds - -> TcM (TcRecordBinds, LIE) - -tcRecordBinds tycon ty_args rbinds - = mapAndUnzipTc do_bind rbinds `thenTc` \ (rbinds', lies) -> - returnTc (rbinds', plusLIEs lies) - where - 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 - - tcExpr rhs field_ty `thenTc` \ (rhs', lie) -> - - returnTc ((sel_id, rhs', pun_flag), lie) - -badFields rbinds data_con - = [field_name | (field_name, _, _) <- rbinds, - not (field_name `elem` field_names) - ] + :: DataCon + -> [(FieldLabel,TcType)] -- Expected type for each field + -> HsRecordBinds Name + -> TcM (HsRecordBinds TcId) + +tcRecordBinds data_con flds_w_tys rbinds + = do { mb_binds <- mappM do_bind rbinds + ; return (catMaybes mb_binds) } where - field_names = map fieldLabelName (dataConFieldLabels data_con) + do_bind (L loc field_lbl, rhs) + | Just field_ty <- assocMaybe flds_w_tys field_lbl + = addErrCtxt (fieldCtxt field_lbl) $ + do { rhs' <- tcCheckSigma rhs field_ty + ; sel_id <- tcLookupId field_lbl + ; ASSERT( isRecordSelector sel_id ) + return (Just (L loc sel_id, rhs')) } + | otherwise + = do { addErrTc (badFieldCon data_con field_lbl) + ; return 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_` + + doptM Opt_WarnMissingFields `thenM` \ warn -> + checkM (not (warn && notNull missing_ns_fields)) + (warnTc True (missingFields data_con missing_ns_fields)) -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 + missing_s_fields = [ fl | (fl, str) <- field_info, isMarkedStrict str, - not (fieldLabelName fl `elem` field_names_used) + not (fl `elem` field_names_used) ] - other_missing_fields + missing_ns_fields = [ fl | (fl, str) <- field_info, not (isMarkedStrict str), - not (fieldLabelName fl `elem` field_names_used) + not (fl `elem` field_names_used) ] - field_names_used = [ field_name | (field_name, _, _) <- rbinds ] + field_names_used = recBindFields rbinds field_labels = dataConFieldLabels data_con field_info = zipEqual "missingFields" field_labels - (dropList ex_theta (dataConStrictMarks data_con)) - -- The 'drop' is because dataConStrictMarks - -- includes the existential dictionaries - (_, _, _, ex_theta, _, _) = dataConSig data_con + 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 ([TcExpr], LIE) - -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 :: [LHsExpr Name] -> [TcType] -> TcM [LHsExpr TcId] + +tcCheckRhos [] [] = returnM [] +tcCheckRhos (expr:exprs) (ty:tys) + = tcCheckRho expr ty `thenM` \ expr' -> + tcCheckRhos exprs tys `thenM` \ exprs' -> + returnM (expr':exprs') +tcCheckRhos exprs tys = pprPanic "tcCheckRhos" (ppr exprs $$ ppr tys) \end{code} @@ -977,16 +1019,10 @@ tcMonoExprs (expr:exprs) (ty:tys) Overloaded literals. \begin{code} -tcLit :: HsLit -> TcType -> TcM (TcExpr, LIE) -tcLit (HsLitLit s _) res_ty - = tcLookupClass cCallableClassName `thenNF_Tc` \ cCallableClass -> - newDicts (LitLitOrigin (unpackFS s)) - [mkClassPred cCallableClass [res_ty]] `thenNF_Tc` \ dicts -> - returnTc (HsLit (HsLitLit s res_ty), mkLIE dicts) - +tcLit :: HsLit -> Expected TcRhoType -> TcM (HsExpr TcId) tcLit lit res_ty - = unifyTauTy res_ty (simpleHsLitTy lit) `thenTc_` - returnTc (HsLit lit, emptyLIE) + = zapExpectedTo res_ty (hsLitType lit) `thenM_` + returnM (HsLit lit) \end{code} @@ -996,8 +1032,6 @@ tcLit lit res_ty %* * %************************************************************************ -Mini-utils: - Boring and alphabetical: \begin{code} arithSeqCtxt expr @@ -1012,9 +1046,16 @@ caseCtxt expr caseScrutCtxt expr = hang (ptext SLIT("In the scrutinee of a case expression:")) 4 (ppr expr) -exprSigCtxt expr - = hang (ptext SLIT("When checking the type signature of the expression:")) - 4 (ppr expr) +exprCtxt expr + = hang (ptext SLIT("In the expression:")) 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)) listCtxt expr = hang (ptext SLIT("In the list element:")) 4 (ppr expr) @@ -1025,51 +1066,57 @@ parrCtxt expr predCtxt expr = hang (ptext SLIT("In the predicate expression:")) 4 (ppr expr) -exprCtxt expr - = hang (ptext SLIT("In the expression:")) 4 (ppr expr) - -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 - 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:") <+> ppr fun_ty]) + the_app = foldl mkHsApp fun args -- Used in error messages +nonVanillaUpd tycon + = vcat [ptext SLIT("Record update for the non-Haskell-98 data type") <+> quotes (ppr tycon) + <+> ptext SLIT("is not (yet) supported"), + ptext SLIT("Use pattern-matching instead")] 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 +naughtyRecordSel sel_id + = ptext SLIT("Cannot use record selector") <+> quotes (ppr sel_id) <+> + ptext SLIT("as a function due to escaped type variables") $$ + ptext SLIT("Probably fix: use pattern-matching syntax instead") + 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)] +missingStrictFields :: DataCon -> [FieldLabel] -> SDoc +missingStrictFields con fields + = header <> rest + where + 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 + +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 -> FieldLabel -> 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}