X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Fcompiler%2Ftypecheck%2FTcExpr.lhs;h=cf94f27f19c2157dcbe917e09508dcd825735453;hb=c5a65b1704212e3f4354841ff480c660a3b51fb6;hp=39e7e4057f4cb8a8cc64d65622e6ea217c3e74c6;hpb=56b5a8b862d4eaeeaa941dd53e3d1009bdeadc0d;p=ghc-hetmet.git diff --git a/ghc/compiler/typecheck/TcExpr.lhs b/ghc/compiler/typecheck/TcExpr.lhs index 39e7e40..cf94f27 100644 --- a/ghc/compiler/typecheck/TcExpr.lhs +++ b/ghc/compiler/typecheck/TcExpr.lhs @@ -4,26 +4,25 @@ \section[TcExpr]{Typecheck an expression} \begin{code} -module TcExpr ( tcExpr, tcExpr_id, tcMonoExpr ) where +module TcExpr ( tcCheckSigma, tcCheckRho, tcInferRho, tcMonoExpr ) where #include "HsVersions.h" #ifdef GHCI /* Only if bootstrapped */ import {-# SOURCE #-} TcSplice( tcSpliceExpr, tcBracket ) -import HsSyn ( HsReify(..), ReifyFlavour(..) ) +import Id ( Id ) import TcType ( isTauTy ) -import TcEnv ( bracketOK, tcMetaTy, checkWellStaged, metaLevel ) -import Name ( isExternalName ) +import TcEnv ( checkWellStaged ) +import HsSyn ( nlHsApp ) import qualified DsMeta #endif -import HsSyn ( HsExpr(..), HsLit(..), ArithSeqInfo(..), recBindFields ) -import RnHsSyn ( RenamedHsExpr, RenamedRecordBinds ) -import TcHsSyn ( TcExpr, TcRecordBinds, hsLitType, mkHsDictApp, mkHsTyApp, mkHsLet ) +import HsSyn ( HsExpr(..), LHsExpr, HsLit(..), ArithSeqInfo(..), recBindFields, + HsMatchContext(..), HsRecordBinds, mkHsApp, nlHsVar ) +import TcHsSyn ( hsLitType, mkHsDictApp, mkHsTyApp, (<$>) ) import TcRnMonad -import TcUnify ( tcSubExp, tcGen, (<$>), - unifyTauTy, unifyFunTy, unifyListTy, unifyPArrTy, - unifyTupleTy ) +import TcUnify ( Expected(..), newHole, zapExpectedType, zapExpectedTo, tcSubExp, tcGen, + unifyFunTy, zapToListTy, zapToPArrTy, zapToTupleTy ) import BasicTypes ( isMarkedStrict ) import Inst ( InstOrigin(..), newOverloadedLit, newMethodFromName, newIPDict, @@ -31,44 +30,45 @@ import Inst ( InstOrigin(..), instToId, tcInstCall, tcInstDataCon ) import TcBinds ( tcBindsAndThen ) -import TcEnv ( tcLookupClass, tcLookupGlobal_maybe, tcLookupIdLvl, - tcLookupTyCon, tcLookupDataCon, tcLookupId +import TcEnv ( tcLookup, tcLookupId, checkProcLevel, + tcLookupDataCon, tcLookupGlobalId ) -import TcMatches ( tcMatchesCase, tcMatchLambda, tcDoStmts ) -import TcMonoType ( tcHsSigType, UserTypeCtxt(..) ) +import TcArrows ( tcProc ) +import TcMatches ( tcMatchesCase, tcMatchLambda, tcDoStmts, tcThingWithSig, TcMatchCtxt(..) ) +import TcHsType ( tcHsSigType, UserTypeCtxt(..) ) import TcPat ( badFieldCon ) -import TcMType ( tcInstTyVars, tcInstType, newHoleTyVarTy, zapToType, - newTyVarTy, newTyVarTys, zonkTcType, readHoleResult ) +import TcMType ( tcInstTyVars, tcInstType, newTyVarTy, zonkTcType ) import TcType ( TcType, TcSigmaType, TcRhoType, TyVarDetails(VanillaTv), tcSplitFunTys, tcSplitTyConApp, mkTyVarTys, isSigmaTy, mkFunTy, mkFunTys, - mkTyConApp, mkClassPred, tcFunArgTy, - tyVarsOfTypes, isLinearPred, - liftedTypeKind, openTypeKind, - tcSplitSigmaTy, tcTyConAppTyCon, - tidyOpenType + mkTyConApp, tyVarsOfTypes, isLinearPred, + tcSplitSigmaTy, tidyOpenType ) +import Kind ( openTypeKind, liftedTypeKind, argTypeKind ) + import FieldLabel ( FieldLabel, fieldLabelName, fieldLabelType, fieldLabelTyCon ) -import Id ( Id, idType, recordSelectorFieldLabel, isRecordSelector ) -import DataCon ( DataCon, dataConFieldLabels, dataConSig, dataConStrictMarks, dataConWrapId ) +import Id ( idType, recordSelectorFieldLabel, isRecordSelector ) +import DataCon ( DataCon, dataConFieldLabels, dataConStrictMarks, dataConWrapId ) import Name ( Name ) -import TyCon ( TyCon, tyConTyVars, tyConTheta, isAlgTyCon, tyConDataCons, isClassTyCon ) +import TyCon ( TyCon, tyConTyVars, tyConTheta, tyConDataCons ) import Subst ( mkTopTyVarSubst, substTheta, substTy ) import VarSet ( emptyVarSet, elemVarSet ) import TysWiredIn ( boolTy ) -import PrelNames ( cCallableClassName, cReturnableClassName, - enumFromName, enumFromThenName, +import PrelNames ( enumFromName, enumFromThenName, enumFromToName, enumFromThenToName, - enumFromToPName, enumFromThenToPName, - ioTyConName + enumFromToPName, enumFromThenToPName ) import ListSetOps ( minusList ) import CmdLineOpts import HscTypes ( TyThing(..) ) - +import SrcLoc ( Located(..), unLoc, getLoc ) import Util import Outputable import FastString + +#ifdef DEBUG +import TyCon ( isAlgTyCon ) +#endif \end{code} %************************************************************************ @@ -78,51 +78,77 @@ import FastString %************************************************************************ \begin{code} -tcExpr :: RenamedHsExpr -- Expession to type check - -> TcSigmaType -- Expected type (could be a polytpye) - -> TcM TcExpr -- Generalised expr with expected type +-- 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 +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 - - | otherwise - = tcGen expected_ty emptyVarSet ( - tcMonoExpr expr +tc_expr' expr sigma_ty + | isSigmaTy sigma_ty + = tcGen sigma_ty emptyVarSet ( + \ rho_ty -> tcCheckRho expr rho_ty ) `thenM` \ (gen_fn, expr') -> - returnM (gen_fn <$> expr') + returnM (L (getLoc expr') (gen_fn <$> unLoc expr')) + +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)) = 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 - -> 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 + -> TcM (LHsExpr TcId) + +tcMonoExpr (L loc expr) res_ty + = addSrcSpan loc (do { expr' <- tc_expr expr res_ty + ; return (L loc expr') }) -tcMonoExpr (HsVar name) res_ty +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') -tcMonoExpr (HsIPVar ip) res_ty +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 openTypeKind `thenM` \ ip_ty -> - newIPDict (IPOcc ip) ip ip_ty `thenM` \ (ip', inst) -> + 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') @@ -136,20 +162,14 @@ tcMonoExpr (HsIPVar ip) res_ty %************************************************************************ \begin{code} -tcMonoExpr in_expr@(ExprWithTySig expr poly_ty) res_ty - = addErrCtxt (exprSigCtxt in_expr) $ - tcHsSigType ExprSigCtxt poly_ty `thenM` \ sig_tc_ty -> - tcExpr expr sig_tc_ty `thenM` \ expr' -> - - -- 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 - tcInstCall SignatureOrigin sig_tc_ty `thenM` \ (inst_fn, inst_sig_ty) -> - tcSubExp res_ty inst_sig_ty `thenM` \ co_fn -> - - returnM (co_fn <$> inst_fn expr') - -tcMonoExpr (HsType ty) res_ty +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) @@ -166,24 +186,29 @@ 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 `thenM` \ expr' -> - returnM (HsPar expr') -tcMonoExpr (HsSCC lbl expr) res_ty = tcMonoExpr expr res_ty `thenM` \ expr' -> - returnM (HsSCC lbl expr') - -tcMonoExpr (HsCoreAnn lbl expr) res_ty = tcMonoExpr expr res_ty `thenM` \ expr' -> -- hdaume: core annotation +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') -tcMonoExpr (NegApp expr neg_name) res_ty - = tcMonoExpr (HsApp (HsVar neg_name) expr) res_ty + +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 -tcMonoExpr (HsLam match) res_ty +tc_expr (HsLam match) res_ty = tcMatchLambda match res_ty `thenM` \ match' -> returnM (HsLam match') -tcMonoExpr (HsApp e1 e2) res_ty +tc_expr (HsApp e1 e2) res_ty = tcApp e1 [e2] res_ty \end{code} @@ -198,8 +223,8 @@ a type error will occur if they aren't. -- or just -- op e -tcMonoExpr in_expr@(SectionL arg1 op) res_ty - = tcExpr_id op `thenM` \ (op', op_ty) -> +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) $ @@ -209,8 +234,8 @@ tcMonoExpr in_expr@(SectionL arg1 op) res_ty -- Right sections, equivalent to \ x -> x op expr, or -- \ x -> op x expr -tcMonoExpr in_expr@(SectionR op arg2) res_ty - = tcExpr_id op `thenM` \ (op', op_ty) -> +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) $ @@ -219,8 +244,8 @@ tcMonoExpr in_expr@(SectionR op arg2) res_ty -- equivalent to (op e1) e2: -tcMonoExpr in_expr@(OpApp arg1 op fix arg2) res_ty - = tcExpr_id op `thenM` \ (op', op_ty) -> +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' -> @@ -230,15 +255,16 @@ tcMonoExpr in_expr@(OpApp arg1 op fix arg2) res_ty \end{code} \begin{code} -tcMonoExpr (HsLet binds expr) res_ty +tc_expr (HsLet binds (L loc expr)) res_ty = tcBindsAndThen - HsLet + glue binds -- Bindings to check - (tcMonoExpr expr res_ty) + (tc_expr expr res_ty) + where + glue bind expr = HsLet [bind] (L loc expr) -tcMonoExpr in_expr@(HsCase scrut matches src_loc) res_ty - = addSrcLoc src_loc $ - addErrCtxt (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 @@ -246,128 +272,63 @@ 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 `thenM` \ (scrut_ty, matches') -> + tcMatchesCase match_ctxt matches res_ty `thenM` \ (scrut_ty, matches') -> addErrCtxt (caseScrutCtxt scrut) ( - tcMonoExpr scrut scrut_ty + tcCheckRho scrut scrut_ty ) `thenM` \ scrut' -> - returnM (HsCase scrut' matches' src_loc) + returnM (HsCase scrut' matches') + where + match_ctxt = MC { mc_what = CaseAlt, + mc_body = tcMonoExpr } -tcMonoExpr (HsIf pred b1 b2 src_loc) res_ty - = addSrcLoc src_loc $ - addErrCtxt (predCtxt pred) ( - tcMonoExpr pred boolTy ) `thenM` \ pred' -> +tc_expr (HsIf pred b1 b2) res_ty + = addErrCtxt (predCtxt pred) ( + tcCheckRho pred boolTy ) `thenM` \ pred' -> - zapToType res_ty `thenM` \ res_ty' -> + zapExpectedType res_ty openTypeKind `thenM` \ res_ty' -> -- C.f. the call to zapToType in TcMatches.tcMatches - tcMonoExpr b1 res_ty' `thenM` \ b1' -> - tcMonoExpr b2 res_ty' `thenM` \ b2' -> - returnM (HsIf pred' b1' b2' src_loc) + tcCheckRho b1 res_ty' `thenM` \ b1' -> + tcCheckRho b2 res_ty' `thenM` \ b2' -> + returnM (HsIf pred' b1' b2') -tcMonoExpr (HsDo do_or_lc stmts method_names _ src_loc) res_ty - = addSrcLoc src_loc $ - tcDoStmts do_or_lc stmts method_names res_ty `thenM` \ (binds, stmts', methods') -> - returnM (mkHsLet binds (HsDo do_or_lc stmts' methods' res_ty src_loc)) +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') -tcMonoExpr in_expr@(ExplicitList _ exprs) res_ty -- Non-empty list - = unifyListTy res_ty `thenM` \ elt_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) $ - tcMonoExpr expr elt_ty + tcCheckRho expr elt_ty -tcMonoExpr in_expr@(ExplicitPArr _ exprs) res_ty -- maybe empty - = unifyPArrTy res_ty `thenM` \ 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 = addErrCtxt (parrCtxt expr) $ - tcMonoExpr expr elt_ty + tcCheckRho expr elt_ty -tcMonoExpr (ExplicitTuple exprs boxity) res_ty - = unifyTupleTy boxity (length exprs) res_ty `thenM` \ arg_tys -> - tcMonoExprs exprs arg_tys `thenM` \ exprs' -> +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) -\end{code} - - -%************************************************************************ -%* * - Foreign calls -%* * -%************************************************************************ - -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 - - = getDOpts `thenM` \ 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."]) - `thenM_` - -- Get the callable and returnable classes. - tcLookupClass cCallableClassName `thenM` \ cCallableClass -> - tcLookupClass cReturnableClassName `thenM` \ cReturnableClass -> - tcLookupTyCon ioTyConName `thenM` \ ioTyCon -> - let - new_arg_dict (arg, arg_ty) - = newDicts (CCallOrigin (unpackFS lbl) (Just arg)) - [mkClassPred cCallableClass [arg_ty]] `thenM` \ arg_dicts -> - returnM arg_dicts -- Actually a singleton bag - - 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 `thenM` \ arg_tys -> - tcMonoExprs args arg_tys `thenM` \ args' -> - - -- 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 `thenM` \ result_ty -> - let - io_result_ty = mkTyConApp ioTyCon [result_ty] - in - unifyTauTy res_ty io_result_ty `thenM_` - - -- Construct the extra insts, which encode the - -- constraints on the argument and result types. - mappM new_arg_dict (zipEqual "tcMonoExpr:CCall" args arg_tys) `thenM` \ ccarg_dicts_s -> - newDicts result_origin [mkClassPred cReturnableClass [result_ty]] `thenM` \ ccres_dict -> - extendLIEs (ccres_dict ++ concat ccarg_dicts_s) `thenM_` - returnM (HsCCall lbl args' may_gc is_casm io_result_ty) +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 @@ -375,19 +336,19 @@ tcMonoExpr e0@(HsCCall lbl args may_gc is_casm ignored_fake_result_ty) res_ty %************************************************************************ \begin{code} -tcMonoExpr expr@(RecordCon con_name rbinds) res_ty +tc_expr expr@(RecordCon con@(L _ con_name) rbinds) res_ty = addErrCtxt (recordConCtxt expr) $ - tcId con_name `thenM` \ (con_expr, con_tau) -> + addLocM tcId con `thenM` \ (con_expr, con_tau) -> let (_, record_ty) = tcSplitFunTys con_tau (tycon, ty_args) = tcSplitTyConApp record_ty in ASSERT( isAlgTyCon tycon ) - unifyTauTy res_ty record_ty `thenM_` + 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 `thenM` \ data_con -> + tcLookupDataCon con_name `thenM` \ data_con -> let bad_fields = badFields rbinds data_con in @@ -402,7 +363,8 @@ tcMonoExpr expr@(RecordCon con_name rbinds) res_ty -- Check for missing fields checkMissingFields data_con rbinds `thenM_` - returnM (RecordConOut data_con con_expr rbinds') + 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: @@ -430,23 +392,23 @@ tcMonoExpr expr@(RecordCon con_name rbinds) res_ty -- -- All this is done in STEP 4 below. -tcMonoExpr expr@(RecordUpd record_expr rbinds) res_ty +tc_expr 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 = recBindFields rbinds + field_names = map fst rbinds in - mappM tcLookupGlobal_maybe field_names `thenM` \ 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, - not (is_selector maybe_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 ] - is_selector (Just (AnId sel_id)) = isRecordSelector sel_id -- Excludes class ops - is_selector other = False in checkM (null bad_guys) (sequenceM bad_guys `thenM_` failM) `thenM_` @@ -454,7 +416,7 @@ tcMonoExpr expr@(RecordUpd record_expr rbinds) res_ty -- 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 + 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 @@ -475,7 +437,7 @@ tcMonoExpr expr@(RecordUpd record_expr rbinds) res_ty let result_record_ty = mkTyConApp tycon result_inst_tys in - unifyTauTy res_ty result_record_ty `thenM_` + zapExpectedTo res_ty result_record_ty `thenM_` tcRecordBinds tycon result_inst_tys rbinds `thenM` \ rbinds' -> -- STEP 4 @@ -507,7 +469,7 @@ tcMonoExpr expr@(RecordUpd record_expr rbinds) res_ty let record_ty = mkTyConApp tycon inst_tys in - tcMonoExpr record_expr record_ty `thenM` \ record_expr' -> + tcCheckRho record_expr record_ty `thenM` \ record_expr' -> -- STEP 6 -- Figure out the LIE we need. We have to generate some @@ -536,69 +498,69 @@ tcMonoExpr expr@(RecordUpd record_expr rbinds) res_ty %************************************************************************ \begin{code} -tcMonoExpr (ArithSeqIn seq@(From expr)) res_ty - = unifyListTy res_ty `thenM` \ elt_ty -> - tcMonoExpr expr elt_ty `thenM` \ expr' -> +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 (HsVar enum_from) (From expr')) + returnM (ArithSeqOut (nlHsVar enum_from) (From expr')) -tcMonoExpr in_expr@(ArithSeqIn seq@(FromThen expr1 expr2)) res_ty +tc_expr in_expr@(ArithSeqIn seq@(FromThen expr1 expr2)) res_ty = addErrCtxt (arithSeqCtxt in_expr) $ - unifyListTy res_ty `thenM` \ elt_ty -> - tcMonoExpr expr1 elt_ty `thenM` \ expr1' -> - tcMonoExpr expr2 elt_ty `thenM` \ expr2' -> + 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 (HsVar enum_from_then) (FromThen expr1' expr2')) + returnM (ArithSeqOut (nlHsVar enum_from_then) (FromThen expr1' expr2')) -tcMonoExpr in_expr@(ArithSeqIn seq@(FromTo expr1 expr2)) res_ty +tc_expr in_expr@(ArithSeqIn seq@(FromTo expr1 expr2)) res_ty = addErrCtxt (arithSeqCtxt in_expr) $ - unifyListTy res_ty `thenM` \ elt_ty -> - tcMonoExpr expr1 elt_ty `thenM` \ expr1' -> - tcMonoExpr expr2 elt_ty `thenM` \ expr2' -> + 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 (HsVar enum_from_to) (FromTo expr1' expr2')) + returnM (ArithSeqOut (nlHsVar enum_from_to) (FromTo expr1' expr2')) -tcMonoExpr in_expr@(ArithSeqIn seq@(FromThenTo expr1 expr2 expr3)) res_ty +tc_expr in_expr@(ArithSeqIn seq@(FromThenTo expr1 expr2 expr3)) res_ty = addErrCtxt (arithSeqCtxt in_expr) $ - unifyListTy res_ty `thenM` \ elt_ty -> - tcMonoExpr expr1 elt_ty `thenM` \ expr1' -> - tcMonoExpr expr2 elt_ty `thenM` \ expr2' -> - tcMonoExpr expr3 elt_ty `thenM` \ expr3' -> + 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 (HsVar eft) (FromThenTo expr1' expr2' expr3')) + returnM (ArithSeqOut (nlHsVar eft) (FromThenTo expr1' expr2' expr3')) -tcMonoExpr in_expr@(PArrSeqIn seq@(FromTo expr1 expr2)) res_ty +tc_expr in_expr@(PArrSeqIn seq@(FromTo expr1 expr2)) res_ty = addErrCtxt (parrSeqCtxt in_expr) $ - unifyPArrTy res_ty `thenM` \ elt_ty -> - tcMonoExpr expr1 elt_ty `thenM` \ expr1' -> - tcMonoExpr expr2 elt_ty `thenM` \ expr2' -> + 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 (HsVar enum_from_to) (FromTo expr1' expr2')) + returnM (PArrSeqOut (nlHsVar enum_from_to) (FromTo expr1' expr2')) -tcMonoExpr in_expr@(PArrSeqIn seq@(FromThenTo expr1 expr2 expr3)) res_ty +tc_expr in_expr@(PArrSeqIn seq@(FromThenTo expr1 expr2 expr3)) res_ty = addErrCtxt (parrSeqCtxt in_expr) $ - unifyPArrTy res_ty `thenM` \ elt_ty -> - tcMonoExpr expr1 elt_ty `thenM` \ expr1' -> - tcMonoExpr expr2 elt_ty `thenM` \ expr2' -> - tcMonoExpr expr3 elt_ty `thenM` \ expr3' -> + 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 (HsVar eft) (FromThenTo expr1' expr2' expr3')) + returnM (PArrSeqOut (nlHsVar eft) (FromThenTo expr1' expr2' expr3')) -tcMonoExpr (PArrSeqIn _) _ +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 @@ -614,21 +576,10 @@ tcMonoExpr (PArrSeqIn _) _ \begin{code} #ifdef GHCI /* Only if bootstrapped */ -- Rename excludes these cases otherwise - -tcMonoExpr (HsSplice n expr loc) res_ty = addSrcLoc loc (tcSpliceExpr n expr res_ty) -tcMonoExpr (HsBracket brack loc) res_ty = addSrcLoc loc (tcBracket brack res_ty) - -tcMonoExpr (HsReify (Reify flavour name)) res_ty - = addErrCtxt (ptext SLIT("At the reification of") <+> ppr name) $ - tcMetaTy tycon_name `thenM` \ reify_ty -> - unifyTauTy res_ty reify_ty `thenM_` - returnM (HsReify (ReifyOut flavour name)) - where - tycon_name = case flavour of - ReifyDecl -> DsMeta.declTyConName - ReifyType -> DsMeta.typeTyConName - ReifyFixity -> pprPanic "tcMonoExpr: cant do reifyFixity yet" (ppr name) -#endif GHCI +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} @@ -639,7 +590,7 @@ tcMonoExpr (HsReify (Reify flavour name)) res_ty %************************************************************************ \begin{code} -tcMonoExpr other _ = pprPanic "tcMonoExpr" (ppr other) +tc_expr other _ = pprPanic "tcMonoExpr" (ppr other) \end{code} @@ -651,41 +602,59 @@ tcMonoExpr other _ = pprPanic "tcMonoExpr" (ppr other) \begin{code} -tcApp :: RenamedHsExpr -> [RenamedHsExpr] -- Function and args - -> TcType -- Expected result type of application - -> TcM TcExpr -- 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 `thenM` \ (fun', fun_ty) -> + tcInferRho fun `thenM` \ (fun', fun_ty) -> addErrCtxt (wrongArgsCtxt "too many" fun args) ( traceTc (text "tcApp" <+> (ppr fun $$ ppr fun_ty)) `thenM_` split_fun_ty fun_ty (length args) ) `thenM` \ (expected_arg_tys, actual_result_ty) -> - -- Now typecheck the args - mappM (tcArg fun) - (zip3 args expected_arg_tys [1..]) `thenM` \ args' -> - - -- Unify with expected result after type-checking the args - -- so that the info from args percolates to 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.] + addErrCtxtM (checkArgsCtxt fun args res_ty actual_result_ty) - (tcSubExp res_ty actual_result_ty) `thenM` \ co_fn -> + (tcSubExp res_ty actual_result_ty) `thenM` \ co_fn -> + + -- Now typecheck the args + mappM (tcArg fun) + (zip3 args expected_arg_tys [1..]) `thenM` \ args' -> - returnM (co_fn <$> foldl HsApp fun' args') + returnM (co_fn <$> 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 +-- 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 @@ -704,7 +673,7 @@ checkArgsCtxt fun args expected_res_ty actual_res_ty tidy_env returnM (env2, message) -split_fun_ty :: TcType -- The type of the function +split_fun_ty :: TcRhoType -- The type of the function -> Int -- Number of arguments -> TcM ([TcType], -- Function argument types TcType) -- Function result types @@ -720,13 +689,13 @@ split_fun_ty fun_ty n \end{code} \begin{code} -tcArg :: RenamedHsExpr -- The function (for error messages) - -> (RenamedHsExpr, TcSigmaType, Int) -- Actual argument and expected arg type - -> TcM TcExpr -- 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) = addErrCtxt (funAppCtxt the_fun arg arg_no) $ - tcExpr arg expected_arg_ty + tcCheckSigma arg expected_arg_ty \end{code} @@ -759,69 +728,70 @@ This gets a bit less sharing, but b) perhaps fewer separated lambdas \begin{code} -tcId :: Name -> TcM (TcExpr, TcType) +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" - tcLookupGlobal_maybe name `thenM` \ maybe_thing -> - case maybe_thing of { - Just (ADataCon data_con) -> inst_data_con data_con ; - other -> - - -- OK, so now look for ordinary Ids - tcLookupIdLvl name `thenM` \ (id, bind_lvl) -> + 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 #ifndef GHCI - loop (HsVar id) (idType id) -- Non-TH case + 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_` -#else /* GHCI is on */ -- Check for cross-stage lifting - getStage `thenM` \ use_stage -> - case use_stage of - Brack use_lvl ps_var lie_var - | use_lvl > bind_lvl && not (isExternalName name) - -> -- E.g. \x -> [| h x |] + 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. - -- - -- NB: During type-checking, isExernalName is true of - -- top level things, and false of nested bindings - -- Top-level things don't need lifting. - - let - id_ty = idType id - in - checkTc (isTauTy id_ty) (polySpliceErr id) `thenM_` + 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 + 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, HsApp (HsVar lift) (HsVar id)) : ps) `thenM_` - - returnM (HsVar id, id_ty)) - - other -> - checkWellStaged (quotes (ppr id)) bind_lvl use_stage `thenM_` - loop (HsVar id) (idType id) -#endif - } + -- 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)) - where - orig = OccurrenceOf name + 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 @@ -833,7 +803,7 @@ tcId name -- Look up the Id and instantiate its type loop fun fun_ty | isSigmaTy fun_ty = tcInstCall orig fun_ty `thenM` \ (inst_fn, tau) -> - loop (inst_fn fun) tau + loop (inst_fn <$> fun) tau | otherwise = returnM (fun, fun_ty) @@ -855,30 +825,20 @@ tcId name -- Look up the Id and instantiate its type -- 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 + -- 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_` - returnM (mkHsDictApp (mkHsTyApp (HsVar (dataConWrapId data_con)) ty_args) - (map instToId ex_dicts), + getSrcSpanM `thenM` \ loc -> + returnM (unLoc (mkHsDictApp (mkHsTyApp (L loc (HsVar (dataConWrapId data_con))) ty_args) + (map instToId ex_dicts)), 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. + -- ToDo: nasty loc/unloc stuff here -\begin{code} -tcExpr_id :: RenamedHsExpr -> TcM (TcExpr, TcType) -tcExpr_id (HsVar name) = tcId name -tcExpr_id expr = newHoleTyVarTy `thenM` \ id_ty -> - tcMonoExpr expr id_ty `thenM` \ expr' -> - readHoleResult id_ty `thenM` \ id_ty' -> - returnM (expr', id_ty') + orig = OccurrenceOf name \end{code} - %************************************************************************ %* * \subsection{Record bindings} @@ -906,17 +866,17 @@ This extends OK when the field types are universally quantified. tcRecordBinds :: TyCon -- Type constructor for the record -> [TcType] -- Args of this type constructor - -> RenamedRecordBinds - -> TcM TcRecordBinds + -> HsRecordBinds Name + -> TcM (HsRecordBinds TcId) tcRecordBinds tycon ty_args rbinds = mappM do_bind rbinds where tenv = mkTopTyVarSubst (tyConTyVars tycon) ty_args - do_bind (field_lbl_name, rhs) + do_bind (L loc field_lbl_name, rhs) = addErrCtxt (fieldCtxt field_lbl_name) $ - tcLookupId field_lbl_name `thenM` \ sel_id -> + tcLookupId field_lbl_name `thenM` \ sel_id -> let field_lbl = recordSelectorFieldLabel sel_id field_ty = substTy tenv (fieldLabelType field_lbl) @@ -929,16 +889,16 @@ tcRecordBinds tycon ty_args rbinds -- The caller of tcRecordBinds has already checked -- that all the fields come from the same type - tcExpr rhs field_ty `thenM` \ rhs' -> + tcCheckSigma rhs field_ty `thenM` \ rhs' -> - returnM (sel_id, rhs') + returnM (L loc sel_id, rhs') badFields rbinds data_con = filter (not . (`elem` field_names)) (recBindFields rbinds) where field_names = map fieldLabelName (dataConFieldLabels data_con) -checkMissingFields :: DataCon -> RenamedRecordBinds -> TcM () +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 @@ -975,25 +935,22 @@ checkMissingFields data_con rbinds field_labels field_strs - field_strs = dropList ex_theta (dataConStrictMarks data_con) - -- The 'drop' is because dataConStrictMarks - -- includes the existential dictionaries - (_, _, _, ex_theta, _, _) = dataConSig data_con + 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] +tcCheckRhos :: [LHsExpr Name] -> [TcType] -> TcM [LHsExpr TcId] -tcMonoExprs [] [] = returnM [] -tcMonoExprs (expr:exprs) (ty:tys) - = tcMonoExpr expr ty `thenM` \ expr' -> - tcMonoExprs exprs tys `thenM` \ exprs' -> +tcCheckRhos [] [] = returnM [] +tcCheckRhos (expr:exprs) (ty:tys) + = tcCheckRho expr ty `thenM` \ expr' -> + tcCheckRhos exprs tys `thenM` \ exprs' -> returnM (expr':exprs') \end{code} @@ -1007,16 +964,9 @@ tcMonoExprs (expr:exprs) (ty:tys) Overloaded literals. \begin{code} -tcLit :: HsLit -> TcType -> TcM TcExpr -tcLit (HsLitLit s _) res_ty - = tcLookupClass cCallableClassName `thenM` \ cCallableClass -> - newDicts (LitLitOrigin (unpackFS s)) - [mkClassPred cCallableClass [res_ty]] `thenM` \ dicts -> - extendLIEs dicts `thenM_` - returnM (HsLit (HsLitLit s res_ty)) - +tcLit :: HsLit -> Expected TcRhoType -> TcM (HsExpr TcId) tcLit lit res_ty - = unifyTauTy res_ty (hsLitType lit) `thenM_` + = zapExpectedTo res_ty (hsLitType lit) `thenM_` returnM (HsLit lit) \end{code} @@ -1041,10 +991,6 @@ 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) @@ -1068,12 +1014,7 @@ predCtxt 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:") <+> ppr fun_ty]) + the_app = foldl mkHsApp fun args -- Used in error messages badFieldsUpd rbinds = hang (ptext SLIT("No constructor has all these fields:")) @@ -1101,15 +1042,17 @@ missingFields con fields = ptext SLIT("Fields of") <+> quotes (ppr con) <+> ptext SLIT("not initialised:") <+> pprWithCommas ppr fields -polySpliceErr :: Id -> SDoc -polySpliceErr id - = ptext SLIT("Can't splice the polymorphic local variable") <+> quotes (ppr id) - 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 + the_app = foldl mkHsApp fun args -- Used in error messages + +#ifdef GHCI +polySpliceErr :: Id -> SDoc +polySpliceErr id + = ptext SLIT("Can't splice the polymorphic local variable") <+> quotes (ppr id) +#endif \end{code}