X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Fcompiler%2Ftypecheck%2FTcExpr.lhs;h=56fc0e37a6582775da321dad9cd56a1a1f319413;hb=10fcd78ccde892feccda3f5eacd221c1de75feea;hp=a0f8ef32b00cf63aa7bd30ae4ed59e6d0c43af20;hpb=438596897ebbe25a07e1c82085cfbc5bdb00f09e;p=ghc-hetmet.git diff --git a/ghc/compiler/typecheck/TcExpr.lhs b/ghc/compiler/typecheck/TcExpr.lhs index a0f8ef3..56fc0e3 100644 --- a/ghc/compiler/typecheck/TcExpr.lhs +++ b/ghc/compiler/typecheck/TcExpr.lhs @@ -4,78 +4,68 @@ \section[TcExpr]{Typecheck an expression} \begin{code} -module TcExpr ( tcExpr, tcPolyExpr, tcId ) where +module TcExpr ( tcExpr, tcMonoExpr, tcId ) where #include "HsVersions.h" import HsSyn ( HsExpr(..), HsLit(..), ArithSeqInfo(..), - HsBinds(..), Stmt(..), StmtCtxt(..), - failureFreePat + HsMatchContext(..), HsDoContext(..), mkMonoBind ) import RnHsSyn ( RenamedHsExpr, RenamedRecordBinds ) -import TcHsSyn ( TcExpr, TcRecordBinds, - mkHsTyApp - ) +import TcHsSyn ( TcExpr, TcRecordBinds, simpleHsLitTy ) import TcMonad -import BasicTypes ( RecFlag(..) ) - -import Inst ( Inst, InstOrigin(..), OverloadedLit(..), - LIE, emptyLIE, unitLIE, plusLIE, plusLIEs, newOverloadedLit, - newMethod, newMethodWithGivenTy, newDicts, instToId ) +import TcUnify ( tcSub, tcGen, (<$>), + unifyTauTy, unifyFunTy, unifyListTy, unifyPArrTy, + unifyTupleTy ) +import BasicTypes ( RecFlag(..), isMarkedStrict ) +import Inst ( InstOrigin(..), + LIE, mkLIE, emptyLIE, unitLIE, plusLIE, plusLIEs, + newOverloadedLit, newMethod, newIPDict, + newDicts, + instToId, tcInstId + ) import TcBinds ( tcBindsAndThen ) -import TcEnv ( TcIdOcc(..), tcInstId, tidyType, - tcLookupLocalValue, tcLookupGlobalValue, tcLookupClassByKey, - tcLookupGlobalValueByKey, - tcExtendGlobalTyVars, tcLookupGlobalValueMaybe, - tcLookupTyCon, tcLookupDataCon +import TcEnv ( tcLookupClass, tcLookupGlobalId, tcLookupGlobal_maybe, + tcLookupTyCon, tcLookupDataCon, tcLookupId ) -import TcMatches ( tcMatchesCase, tcMatchExpected ) -import TcGRHSs ( tcStmts ) -import TcMonoType ( tcHsTcType, checkSigTyVars, sigCtxt ) +import TcMatches ( tcMatchesCase, tcMatchLambda, tcStmts ) +import TcMonoType ( tcHsSigType, UserTypeCtxt(..) ) import TcPat ( badFieldCon ) -import TcSimplify ( tcSimplifyAndCheck ) -import TcType ( TcType, TcTauType, TcMaybe(..), - tcInstTyVars, - tcInstTcType, tcSplitRhoTy, - newTyVarTy, zonkTcType ) - -import Class ( Class ) -import FieldLabel ( FieldLabel, fieldLabelName, fieldLabelType ) -import Id ( idType, recordSelectorFieldLabel, - isRecordSelector, - Id - ) -import DataCon ( dataConFieldLabels, dataConSig, dataConId ) -import Name ( Name ) -import Type ( mkFunTy, mkAppTy, mkTyVarTy, mkTyVarTys, - splitFunTy_maybe, splitFunTys, - mkTyConApp, - splitForAllTys, splitRhoTy, - isTauTy, tyVarsOfType, tyVarsOfTypes, - isForAllTy, splitAlgTyConApp, splitAlgTyConApp_maybe, - boxedTypeKind, openTypeKind, mkArrowKind, - substFlexiTheta +import TcSimplify ( tcSimplifyIPs ) +import TcMType ( tcInstTyVars, newTyVarTy, newTyVarTys, zonkTcType ) +import TcType ( TcType, TcSigmaType, TcPhiType, + tcSplitFunTys, tcSplitTyConApp, + isSigmaTy, mkFunTy, mkAppTy, mkTyConTy, + mkTyConApp, mkClassPred, tcFunArgTy, + tyVarsOfTypes, + liftedTypeKind, openTypeKind, mkArrowKind, + tcSplitSigmaTy, tcTyConAppTyCon, + tidyOpenType ) -import VarEnv ( zipVarEnv ) -import VarSet ( elemVarSet, mkVarSet ) -import TyCon ( tyConDataCons ) -import TysPrim ( intPrimTy, charPrimTy, doublePrimTy, - floatPrimTy, addrPrimTy +import FieldLabel ( FieldLabel, fieldLabelName, fieldLabelType, fieldLabelTyCon ) +import Id ( idType, recordSelectorFieldLabel, isRecordSelector ) +import DataCon ( dataConFieldLabels, dataConSig, + dataConStrictMarks ) -import TysWiredIn ( boolTy, charTy, stringTy ) -import PrelInfo ( ioTyCon_NAME ) -import TcUnify ( unifyTauTy, unifyFunTy, unifyListTy, unifyTupleTy, - unifyUnboxedTupleTy ) -import Unique ( cCallableClassKey, cReturnableClassKey, - enumFromClassOpKey, enumFromThenClassOpKey, - enumFromToClassOpKey, enumFromThenToClassOpKey, - thenMClassOpKey, zeroClassOpKey, returnMClassOpKey +import Name ( Name ) +import TyCon ( TyCon, tyConTyVars, isAlgTyCon, tyConDataCons ) +import Subst ( mkTopTyVarSubst, substTheta, substTy ) +import VarSet ( elemVarSet ) +import TysWiredIn ( boolTy, mkListTy, mkPArrTy, listTyCon, parrTyCon ) +import PrelNames ( cCallableClassName, + cReturnableClassName, + enumFromName, enumFromThenName, + enumFromToName, enumFromThenToName, + enumFromToPName, enumFromThenToPName, + thenMName, failMName, returnMName, ioTyConName ) import Outputable -import Maybes ( maybeToBool ) import ListSetOps ( minusList ) import Util +import CmdLineOpts +import HscTypes ( TyThing(..) ) + \end{code} %************************************************************************ @@ -86,171 +76,64 @@ import Util \begin{code} tcExpr :: RenamedHsExpr -- Expession to type check - -> TcType s -- Expected type (could be a polytpye) - -> TcM s (TcExpr s, LIE s) + -> TcSigmaType -- Expected type (could be a polytpye) + -> TcM (TcExpr, LIE) -- Generalised expr with expected type, and LIE -tcExpr expr ty | isForAllTy ty = -- Polymorphic case - tcPolyExpr expr ty `thenTc` \ (expr', lie, _, _, _) -> - returnTc (expr', lie) +tcExpr expr expected_ty + | not (isSigmaTy expected_ty) -- Monomorphic case + = tcMonoExpr expr expected_ty - | otherwise = -- Monomorphic case - tcMonoExpr expr ty + | otherwise + = tcGen expected_ty (tcMonoExpr expr) `thenTc` \ (gen_fn, expr', lie) -> + returnTc (gen_fn <$> expr', lie) \end{code} %************************************************************************ %* * -\subsection{@tcPolyExpr@ typchecks an application} -%* * -%************************************************************************ - -\begin{code} --- tcPolyExpr is like tcMonoExpr, except that the expected type --- can be a polymorphic one. -tcPolyExpr :: RenamedHsExpr - -> TcType s -- Expected type - -> TcM s (TcExpr s, LIE s, -- Generalised expr with expected type, and LIE - TcExpr s, TcTauType s, LIE s) -- Same thing, but instantiated; tau-type returned - -tcPolyExpr arg expected_arg_ty - = -- Ha! The argument type of the function is a for-all type, - -- An example of rank-2 polymorphism. - - -- To ensure that the forall'd type variables don't get unified with each - -- other or any other types, we make fresh copy of the alleged type - tcInstTcType expected_arg_ty `thenNF_Tc` \ (sig_tyvars, sig_rho) -> - let - (sig_theta, sig_tau) = splitRhoTy sig_rho - in - -- Type-check the arg and unify with expected type - tcExtendGlobalTyVars (mkVarSet sig_tyvars) ( - tcMonoExpr arg sig_tau - ) `thenTc` \ (arg', lie_arg) -> - - -- Check that the arg_tyvars havn't been constrained - -- The interesting bit here is that we must include the free variables - -- of the expected arg ty. Here's an example: - -- runST (newVar True) - -- Here, if we don't make a check, we'll get a type (ST s (MutVar s Bool)) - -- for (newVar True), with s fresh. Then we unify with the runST's arg type - -- forall s'. ST s' a. That unifies s' with s, and a with MutVar s Bool. - -- So now s' isn't unconstrained because it's linked to a. - -- Conclusion: include the free vars of the expected arg type in the - -- list of "free vars" for the signature check. - - tcExtendGlobalTyVars (tyVarsOfType expected_arg_ty) $ - tcAddErrCtxtM (sigCtxt (text "an expression") sig_tau) $ - - checkSigTyVars sig_tyvars `thenTc` \ zonked_sig_tyvars -> - - newDicts SignatureOrigin sig_theta `thenNF_Tc` \ (sig_dicts, dict_ids) -> - -- ToDo: better origin - tcSimplifyAndCheck - (text "tcPolyExpr") - (mkVarSet zonked_sig_tyvars) - sig_dicts lie_arg `thenTc` \ (free_insts, inst_binds) -> - - let - -- This HsLet binds any Insts which came out of the simplification. - -- It's a bit out of place here, but using AbsBind involves inventing - -- a couple of new names which seems worse. - generalised_arg = TyLam zonked_sig_tyvars $ - DictLam dict_ids $ - HsLet (MonoBind inst_binds [] Recursive) - arg' - in - returnTc ( generalised_arg, free_insts, - arg', sig_tau, lie_arg ) -\end{code} - -%************************************************************************ -%* * \subsection{The TAUT rules for variables} %* * %************************************************************************ \begin{code} tcMonoExpr :: RenamedHsExpr -- Expession to type check - -> TcTauType s -- Expected type (could be a type variable) - -> TcM s (TcExpr s, LIE s) + -> TcPhiType -- Expected type (could be a type variable) + -- Definitely no foralls at the top + -- Can be a 'hole'. + -> TcM (TcExpr, LIE) tcMonoExpr (HsVar name) res_ty - = tcId name `thenNF_Tc` \ (expr', lie, id_ty) -> - unifyTauTy res_ty id_ty `thenTc_` - - -- Check that the result type doesn't have any nested for-alls. - -- For example, a "build" on its own is no good; it must be - -- applied to something. - checkTc (isTauTy id_ty) - (lurkingRank2Err name id_ty) `thenTc_` - - returnTc (expr', lie) + = tcId name `thenNF_Tc` \ (expr', lie1, id_ty) -> + tcSub res_ty id_ty `thenTc` \ (co_fn, lie2) -> + returnTc (co_fn <$> expr', lie1 `plusLIE` lie2) + +tcMonoExpr (HsIPVar ip) res_ty + = -- Implicit parameters must have a *tau-type* not a + -- type scheme. We enforce this by creating a fresh + -- type variable as its type. (Because res_ty may not + -- be a tau-type.) + newTyVarTy openTypeKind `thenNF_Tc` \ ip_ty -> + newIPDict (IPOcc ip) ip ip_ty `thenNF_Tc` \ (ip', inst) -> + tcSub res_ty ip_ty `thenTc` \ (co_fn, lie) -> + returnNF_Tc (co_fn <$> HsIPVar ip', lie `plusLIE` unitLIE inst) \end{code} + %************************************************************************ %* * -\subsection{Literals} +\subsection{Expressions type signatures} %* * %************************************************************************ -Overloaded literals. - -\begin{code} -tcMonoExpr (HsLit (HsInt i)) res_ty - = newOverloadedLit (LiteralOrigin (HsInt i)) - (OverloadedIntegral i) - res_ty `thenNF_Tc` \ stuff -> - returnTc stuff - -tcMonoExpr (HsLit (HsFrac f)) res_ty - = newOverloadedLit (LiteralOrigin (HsFrac f)) - (OverloadedFractional f) - res_ty `thenNF_Tc` \ stuff -> - returnTc stuff - - -tcMonoExpr (HsLit lit@(HsLitLit s)) res_ty - = tcLookupClassByKey cCallableClassKey `thenNF_Tc` \ cCallableClass -> - newDicts (LitLitOrigin (_UNPK_ s)) - [(cCallableClass, [res_ty])] `thenNF_Tc` \ (dicts, _) -> - returnTc (HsLitOut lit res_ty, dicts) -\end{code} - -Primitive literals: - \begin{code} -tcMonoExpr (HsLit lit@(HsCharPrim c)) res_ty - = unifyTauTy res_ty charPrimTy `thenTc_` - returnTc (HsLitOut lit charPrimTy, emptyLIE) - -tcMonoExpr (HsLit lit@(HsStringPrim s)) res_ty - = unifyTauTy res_ty addrPrimTy `thenTc_` - returnTc (HsLitOut lit addrPrimTy, emptyLIE) - -tcMonoExpr (HsLit lit@(HsIntPrim i)) res_ty - = unifyTauTy res_ty intPrimTy `thenTc_` - returnTc (HsLitOut lit intPrimTy, emptyLIE) - -tcMonoExpr (HsLit lit@(HsFloatPrim f)) res_ty - = unifyTauTy res_ty floatPrimTy `thenTc_` - returnTc (HsLitOut lit floatPrimTy, emptyLIE) - -tcMonoExpr (HsLit lit@(HsDoublePrim d)) res_ty - = unifyTauTy res_ty doublePrimTy `thenTc_` - returnTc (HsLitOut lit doublePrimTy, emptyLIE) +tcMonoExpr in_expr@(ExprWithTySig expr poly_ty) res_ty + = tcHsSigType ExprSigCtxt poly_ty `thenTc` \ sig_tc_ty -> + tcAddErrCtxt (exprSigCtxt in_expr) $ + tcExpr expr sig_tc_ty `thenTc` \ (expr', lie1) -> + tcSub res_ty sig_tc_ty `thenTc` \ (co_fn, lie2) -> + returnTc (co_fn <$> expr', lie1 `plusLIE` lie2) \end{code} -Unoverloaded literals: - -\begin{code} -tcMonoExpr (HsLit lit@(HsChar c)) res_ty - = unifyTauTy res_ty charTy `thenTc_` - returnTc (HsLitOut lit charTy, emptyLIE) - -tcMonoExpr (HsLit lit@(HsString str)) res_ty - = unifyTauTy res_ty stringTy `thenTc_` - returnTc (HsLitOut lit stringTy, emptyLIE) -\end{code} %************************************************************************ %* * @@ -259,34 +142,19 @@ tcMonoExpr (HsLit lit@(HsString str)) res_ty %************************************************************************ \begin{code} -tcMonoExpr (HsPar expr) res_ty -- preserve parens so printing needn't guess where they go - = tcMonoExpr expr res_ty +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 --- perform the negate *before* overloading the integer, since the case --- of minBound on Ints fails otherwise. Could be done elsewhere, but --- convenient to do it here. - -tcMonoExpr (NegApp (HsLit (HsInt i)) neg) res_ty - = tcMonoExpr (HsLit (HsInt (-i))) res_ty - -tcMonoExpr (NegApp expr neg) res_ty - = tcMonoExpr (HsApp neg expr) res_ty +tcMonoExpr (NegApp expr neg_name) res_ty + = tcMonoExpr (HsApp (HsVar neg_name) expr) res_ty tcMonoExpr (HsLam match) res_ty - = tcMatchExpected match res_ty LambdaBody `thenTc` \ (match',lie) -> + = tcMatchLambda match res_ty `thenTc` \ (match',lie) -> returnTc (HsLam match', lie) -tcMonoExpr (HsApp e1 e2) res_ty = accum e1 [e2] - where - accum (HsApp e1 e2) args = accum e1 (e2:args) - accum fun args - = tcApp fun args res_ty `thenTc` \ (fun', args', lie) -> - returnTc (foldl HsApp fun' args', lie) - --- equivalent to (op e1) e2: -tcMonoExpr (OpApp arg1 op fix arg2) res_ty - = tcApp op [arg1,arg2] res_ty `thenTc` \ (op', [arg1', arg2'], lie) -> - returnTc (OpApp arg1' op' fix arg2', lie) +tcMonoExpr (HsApp e1 e2) res_ty + = tcApp e1 [e2] res_ty \end{code} Note that the operators in sections are expected to be binary, and @@ -300,30 +168,36 @@ a type error will occur if they aren't. -- or just -- op e -tcMonoExpr in_expr@(SectionL arg op) res_ty - = tcApp op [arg] res_ty `thenTc` \ (op', [arg'], lie) -> - - -- Check that res_ty is a function type - -- Without this check we barf in the desugarer on - -- f op = (3 `op`) - -- because it tries to desugar to - -- f op = \r -> 3 op r - -- so (3 `op`) had better be a function! - tcAddErrCtxt (sectionLAppCtxt in_expr) $ - unifyFunTy res_ty `thenTc_` - - returnTc (SectionL arg' op', lie) +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) $ + tcSub res_ty (mkFunTy arg2_ty op_res_ty) `thenTc` \ (co_fn, lie3) -> + returnTc (co_fn <$> SectionL arg1' op', lie1 `plusLIE` lie2 `plusLIE` lie3) -- Right sections, equivalent to \ x -> x op expr, or -- \ x -> op x expr -tcMonoExpr in_expr@(SectionR op expr) res_ty - = tcExpr_id op `thenTc` \ (op', lie1, op_ty) -> - tcAddErrCtxt (sectionRAppCtxt in_expr) $ - split_fun_ty op_ty 2 {- two args -} `thenTc` \ ([arg1_ty, arg2_ty], op_res_ty) -> - tcMonoExpr expr arg2_ty `thenTc` \ (expr',lie2) -> - unifyTauTy res_ty (mkFunTy arg1_ty op_res_ty) `thenTc_` - returnTc (SectionR op' expr', lie1 `plusLIE` lie2) +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) $ + tcSub res_ty (mkFunTy arg1_ty op_res_ty) `thenTc` \ (co_fn, lie3) -> + returnTc (co_fn <$> SectionR op' arg2', lie1 `plusLIE` lie2 `plusLIE` lie3) + +-- 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) $ + tcSub res_ty op_res_ty `thenTc` \ (co_fn, lie3) -> + returnTc (OpApp arg1' op' fix arg2', + lie1 `plusLIE` lie2a `plusLIE` lie2b `plusLIE` lie3) \end{code} The interesting thing about @ccall@ is that it is just a template @@ -334,50 +208,58 @@ arg/result types); unify them with the args/result; and store them for later use. \begin{code} -tcMonoExpr (CCall lbl args may_gc is_asm ignored_fake_result_ty) res_ty - = -- Get the callable and returnable classes. - tcLookupClassByKey cCallableClassKey `thenNF_Tc` \ cCallableClass -> - tcLookupClassByKey cReturnableClassKey `thenNF_Tc` \ cReturnableClass -> - tcLookupTyCon ioTyCon_NAME `thenTc` \ (_,_,ioTyCon) -> +tcMonoExpr e0@(HsCCall lbl args may_gc is_casm ignored_fake_result_ty) res_ty + + = getDOptsTc `thenNF_Tc` \ dflags -> + + checkTc (not (is_casm && dopt_HscLang dflags /= HscC)) + (vcat [text "_casm_ is only supported when compiling via C (-fvia-C).", + text "Either compile with -fvia-C, or, better, rewrite your code", + text "to use the foreign function interface. _casm_s are deprecated", + text "and support for them may one day disappear."]) + `thenTc_` + + -- Get the callable and returnable classes. + tcLookupClass cCallableClassName `thenNF_Tc` \ cCallableClass -> + tcLookupClass cReturnableClassName `thenNF_Tc` \ cReturnableClass -> + tcLookupTyCon ioTyConName `thenNF_Tc` \ ioTyCon -> let new_arg_dict (arg, arg_ty) = newDicts (CCallOrigin (_UNPK_ lbl) (Just arg)) - [(cCallableClass, [arg_ty])] `thenNF_Tc` \ (arg_dicts, _) -> + [mkClassPred cCallableClass [arg_ty]] `thenNF_Tc` \ arg_dicts -> returnNF_Tc arg_dicts -- Actually a singleton bag result_origin = CCallOrigin (_UNPK_ lbl) Nothing {- Not an arg -} in -- Arguments - mapNF_Tc (\ _ -> newTyVarTy openTypeKind) - [1..(length args)] `thenNF_Tc` \ ty_vars -> - tcMonoExprs args ty_vars `thenTc` \ (args', args_lie) -> + 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 unboxed or boxed; the result - -- type must, however, be boxed since it's an argument to the IO + -- The argument types can be unlifted or lifted; the result + -- type must, however, be lifted since it's an argument to the IO -- type constructor. - newTyVarTy boxedTypeKind `thenNF_Tc` \ result_ty -> + newTyVarTy liftedTypeKind `thenNF_Tc` \ result_ty -> let io_result_ty = mkTyConApp ioTyCon [result_ty] - [ioDataCon] = tyConDataCons ioTyCon in unifyTauTy res_ty io_result_ty `thenTc_` -- Construct the extra insts, which encode the -- constraints on the argument and result types. - mapNF_Tc new_arg_dict (zipEqual "tcMonoExpr:CCall" args ty_vars) `thenNF_Tc` \ ccarg_dicts_s -> - newDicts result_origin [(cReturnableClass, [result_ty])] `thenNF_Tc` \ (ccres_dict, _) -> - - returnTc (HsApp (HsVar (RealId (dataConId ioDataCon)) `TyApp` [result_ty]) - (CCall lbl args' may_gc is_asm result_ty), - -- do the wrapping in the newtype constructor here - foldr plusLIE ccres_dict ccarg_dicts_s `plusLIE` args_lie) + mapNF_Tc new_arg_dict (zipEqual "tcMonoExpr:CCall" args arg_tys) `thenNF_Tc` \ ccarg_dicts_s -> + newDicts result_origin [mkClassPred cReturnableClass [result_ty]] `thenNF_Tc` \ ccres_dict -> + returnTc (HsCCall lbl args' may_gc is_casm io_result_ty, + mkLIE (ccres_dict ++ concat ccarg_dicts_s) `plusLIE` args_lie) \end{code} \begin{code} -tcMonoExpr (HsSCC label expr) res_ty +tcMonoExpr (HsSCC lbl expr) res_ty = tcMonoExpr expr res_ty `thenTc` \ (expr', lie) -> - returnTc (HsSCC label expr', lie) + returnTc (HsSCC lbl expr', lie) tcMonoExpr (HsLet binds expr) res_ty = tcBindsAndThen @@ -388,7 +270,7 @@ tcMonoExpr (HsLet binds expr) res_ty where tc_expr = tcMonoExpr expr res_ty `thenTc` \ (expr', lie) -> returnTc (expr', lie) - combiner is_rec bind expr = HsLet (MonoBind bind [] is_rec) expr + combiner is_rec bind expr = HsLet (mkMonoBind bind [] is_rec) expr tcMonoExpr in_expr@(HsCase scrut matches src_loc) res_ty = tcAddSrcLoc src_loc $ @@ -400,8 +282,16 @@ tcMonoExpr in_expr@(HsCase scrut matches src_loc) res_ty -- case (map f) of -- (x:xs) -> ... -- will report that map is applied to too few arguments + -- + -- Not only that, but it's better to check the matches on their + -- own, so that we get the expected results for scoped type variables. + -- f x = case x of + -- (p::a, q::b) -> (q,p) + -- The above should work: the match (p,q) -> (q,p) is polymorphic as + -- claimed by the pattern signatures. But if we typechecked the + -- match with x in scope and x's type as the expected type, we'd be hosed. - tcMatchesCase res_ty matches `thenTc` \ (scrut_ty, matches', lie2) -> + tcMatchesCase matches res_ty `thenTc` \ (scrut_ty, matches', lie2) -> tcAddErrCtxt (caseScrutCtxt scrut) ( tcMonoExpr scrut scrut_ty @@ -425,49 +315,68 @@ tcMonoExpr expr@(HsDo do_or_lc stmts src_loc) res_ty \end{code} \begin{code} -tcMonoExpr in_expr@(ExplicitList exprs) res_ty -- Non-empty list +tcMonoExpr in_expr@(ExplicitList _ exprs) res_ty -- Non-empty list = unifyListTy res_ty `thenTc` \ elt_ty -> mapAndUnzipTc (tc_elt elt_ty) exprs `thenTc` \ (exprs', lies) -> - returnTc (ExplicitListOut elt_ty exprs', plusLIEs lies) + returnTc (ExplicitList elt_ty exprs', plusLIEs lies) where tc_elt elt_ty expr = tcAddErrCtxt (listCtxt expr) $ tcMonoExpr expr elt_ty -tcMonoExpr (ExplicitTuple exprs boxed) res_ty - = (if boxed - then unifyTupleTy (length exprs) res_ty - else unifyUnboxedTupleTy (length exprs) res_ty - ) `thenTc` \ arg_tys -> +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' boxed, plusLIEs lies) + returnTc (ExplicitTuple exprs' boxity, plusLIEs lies) -tcMonoExpr (RecordCon con_name rbinds) res_ty - = tcId con_name `thenNF_Tc` \ (con_expr, con_lie, con_tau) -> +tcMonoExpr expr@(RecordCon con_name rbinds) res_ty + = tcAddErrCtxt (recordConCtxt expr) $ + tcId con_name `thenNF_Tc` \ (con_expr, con_lie, con_tau) -> let - (_, record_ty) = splitFunTys con_tau + (_, record_ty) = tcSplitFunTys con_tau + (tycon, ty_args) = tcSplitTyConApp record_ty in - -- Con is syntactically constrained to be a data constructor - ASSERT( maybeToBool (splitAlgTyConApp_maybe record_ty ) ) + ASSERT( isAlgTyCon tycon ) unifyTauTy res_ty record_ty `thenTc_` -- Check that the record bindings match the constructor - tcLookupDataCon con_name `thenTc` \ (data_con, _, _) -> + -- con_name is syntactically constrained to be a data constructor + tcLookupDataCon con_name `thenTc` \ data_con -> let bad_fields = badFields rbinds data_con in - mapNF_Tc (addErrTc . badFieldCon con_name) bad_fields `thenNF_Tc_` + if not (null bad_fields) then + mapNF_Tc (addErrTc . badFieldCon con_name) bad_fields `thenNF_Tc_` + failTc -- Fail now, because tcRecordBinds will crash on a bad field + else -- Typecheck the record bindings - -- (Do this after checkRecordFields in case there's a field that - -- doesn't match the constructor.) - tcRecordBinds record_ty rbinds `thenTc` \ (rbinds', rbinds_lie) -> + tcRecordBinds tycon ty_args rbinds `thenTc` \ (rbinds', rbinds_lie) -> + + let + (missing_s_fields, missing_fields) = missingFields rbinds data_con + in + checkTcM (null missing_s_fields) + (mapNF_Tc (addErrTc . missingStrictFieldCon con_name) missing_s_fields `thenNF_Tc_` + returnNF_Tc ()) `thenNF_Tc_` + doptsTc Opt_WarnMissingFields `thenNF_Tc` \ warn -> + checkTcM (not (warn && not (null missing_fields))) + (mapNF_Tc ((warnTc True) . missingFieldCon con_name) missing_fields `thenNF_Tc_` + returnNF_Tc ()) `thenNF_Tc_` returnTc (RecordConOut data_con con_expr rbinds', con_lie `plusLIE` rbinds_lie) - -- The main complication with RecordUpd is that we need to explicitly -- handle the *non-updated* fields. Consider: -- @@ -494,32 +403,46 @@ tcMonoExpr (RecordCon con_name rbinds) res_ty -- -- All this is done in STEP 4 below. -tcMonoExpr (RecordUpd record_expr rbinds) res_ty - = tcAddErrCtxt recordUpdCtxt $ +tcMonoExpr expr@(RecordUpd record_expr rbinds) res_ty + = tcAddErrCtxt (recordUpdCtxt expr) $ - -- STEP 1 - -- Figure out the tycon and data cons from the first field name + -- STEP 0 + -- Check that the field names are really field names ASSERT( not (null rbinds) ) let - ((first_field_name, _, _) : rest) = rbinds + field_names = [field_name | (field_name, _, _) <- rbinds] + in + mapNF_Tc tcLookupGlobal_maybe field_names `thenNF_Tc` \ maybe_sel_ids -> + let + bad_guys = [ addErrTc (notSelector field_name) + | (field_name, maybe_sel_id) <- field_names `zip` maybe_sel_ids, + case maybe_sel_id of + Just (AnId sel_id) -> not (isRecordSelector sel_id) + other -> True + ] in - tcLookupGlobalValueMaybe first_field_name `thenNF_Tc` \ maybe_sel_id -> - (case maybe_sel_id of - Just sel_id | isRecordSelector sel_id -> returnTc sel_id - other -> failWithTc (notSelector first_field_name) - ) `thenTc` \ sel_id -> + checkTcM (null bad_guys) (listNF_Tc bad_guys `thenNF_Tc_` failTc) `thenTc_` + + -- STEP 1 + -- Figure out the tycon and data cons from the first field name let - (_, tau) = splitForAllTys (idType sel_id) - Just (data_ty, _) = splitFunTy_maybe tau -- Must succeed since sel_id is a selector - (tycon, _, data_cons) = splitAlgTyConApp data_ty - (con_tyvars, theta, _, _, _, _) = dataConSig (head data_cons) + -- It's OK to use the non-tc splitters here (for a selector) + (Just (AnId sel_id) : _) = maybe_sel_ids + (_, _, tau) = tcSplitSigmaTy (idType sel_id) -- Selectors can be overloaded + -- when the data type has a context + data_ty = tcFunArgTy tau -- Must succeed since sel_id is a selector + tycon = tcTyConAppTyCon data_ty + data_cons = tyConDataCons tycon + (con_tyvars, _, _, _, _, _) = dataConSig (head data_cons) in tcInstTyVars con_tyvars `thenNF_Tc` \ (_, result_inst_tys, _) -> -- STEP 2 - -- Check for bad fields + -- Check that at least one constructor has all the named fields + -- i.e. has an empty set of bad fields returned by badFields checkTc (any (null . badFields rbinds) data_cons) (badFieldsUpd rbinds) `thenTc_` + -- STEP 3 -- Typecheck the update bindings. -- (Do this after checking for bad fields in case there's a field that @@ -528,7 +451,7 @@ tcMonoExpr (RecordUpd record_expr rbinds) res_ty result_record_ty = mkTyConApp tycon result_inst_tys in unifyTauTy res_ty result_record_ty `thenTc_` - tcRecordBinds result_record_ty rbinds `thenTc` \ (rbinds', rbinds_lie) -> + tcRecordBinds tycon result_inst_tys rbinds `thenTc` \ (rbinds', rbinds_lie) -> -- STEP 4 -- Use the un-updated fields to find a vector of booleans saying @@ -537,7 +460,7 @@ tcMonoExpr (RecordUpd record_expr rbinds) res_ty -- WARNING: this code assumes that all data_cons in a common tycon -- have FieldLabels abstracted over the same tyvars. let - upd_field_lbls = [recordSelectorFieldLabel sel_id | (RealId sel_id, _, _) <- rbinds'] + upd_field_lbls = [recordSelectorFieldLabel sel_id | (sel_id, _, _) <- rbinds'] con_field_lbls_s = map dataConFieldLabels data_cons -- A constructor is only relevant to this process if @@ -550,7 +473,7 @@ tcMonoExpr (RecordUpd record_expr rbinds) res_ty mk_inst_ty (tyvar, result_inst_ty) | tyvar `elemVarSet` common_tyvars = returnNF_Tc result_inst_ty -- Same as result type - | otherwise = newTyVarTy boxedTypeKind -- Fresh type + | otherwise = newTyVarTy liftedTypeKind -- Fresh type in mapNF_Tc mk_inst_ty (zip con_tyvars result_inst_tys) `thenNF_Tc` \ inst_tys -> @@ -572,115 +495,119 @@ tcMonoExpr (RecordUpd record_expr rbinds) res_ty -- union the ones that could participate in the update. let (tyvars, theta, _, _, _, _) = dataConSig (head data_cons) - inst_env = zipVarEnv tyvars result_inst_tys - theta' = substFlexiTheta inst_env theta + inst_env = mkTopTyVarSubst tyvars result_inst_tys + theta' = substTheta inst_env theta in - newDicts RecordUpdOrigin theta' `thenNF_Tc` \ (con_lie, dicts) -> + newDicts RecordUpdOrigin theta' `thenNF_Tc` \ dicts -> -- Phew! - returnTc (RecordUpdOut record_expr' result_record_ty dicts rbinds', - con_lie `plusLIE` record_lie `plusLIE` rbinds_lie) + returnTc (RecordUpdOut record_expr' record_ty result_record_ty (map instToId dicts) rbinds', + mkLIE dicts `plusLIE` record_lie `plusLIE` rbinds_lie) tcMonoExpr (ArithSeqIn seq@(From expr)) res_ty - = unifyListTy res_ty `thenTc` \ elt_ty -> - tcMonoExpr expr elt_ty `thenTc` \ (expr', lie1) -> + = unifyListTy res_ty `thenTc` \ elt_ty -> + tcMonoExpr expr elt_ty `thenTc` \ (expr', lie1) -> - tcLookupGlobalValueByKey enumFromClassOpKey `thenNF_Tc` \ sel_id -> + tcLookupGlobalId enumFromName `thenNF_Tc` \ sel_id -> newMethod (ArithSeqOrigin seq) - (RealId sel_id) [elt_ty] `thenNF_Tc` \ (lie2, enum_from_id) -> + sel_id [elt_ty] `thenNF_Tc` \ enum_from -> - returnTc (ArithSeqOut (HsVar enum_from_id) (From expr'), - lie1 `plusLIE` lie2) + returnTc (ArithSeqOut (HsVar (instToId enum_from)) (From expr'), + lie1 `plusLIE` unitLIE enum_from) tcMonoExpr in_expr@(ArithSeqIn seq@(FromThen expr1 expr2)) res_ty = tcAddErrCtxt (arithSeqCtxt in_expr) $ - unifyListTy res_ty `thenTc` \ elt_ty -> - tcMonoExpr expr1 elt_ty `thenTc` \ (expr1',lie1) -> - tcMonoExpr expr2 elt_ty `thenTc` \ (expr2',lie2) -> - tcLookupGlobalValueByKey enumFromThenClassOpKey `thenNF_Tc` \ sel_id -> - newMethod (ArithSeqOrigin seq) - (RealId sel_id) [elt_ty] `thenNF_Tc` \ (lie3, enum_from_then_id) -> + unifyListTy res_ty `thenTc` \ elt_ty -> + tcMonoExpr expr1 elt_ty `thenTc` \ (expr1',lie1) -> + tcMonoExpr expr2 elt_ty `thenTc` \ (expr2',lie2) -> + tcLookupGlobalId enumFromThenName `thenNF_Tc` \ sel_id -> + newMethod (ArithSeqOrigin seq) sel_id [elt_ty] `thenNF_Tc` \ enum_from_then -> - returnTc (ArithSeqOut (HsVar enum_from_then_id) - (FromThen expr1' expr2'), - lie1 `plusLIE` lie2 `plusLIE` lie3) + returnTc (ArithSeqOut (HsVar (instToId enum_from_then)) + (FromThen expr1' expr2'), + lie1 `plusLIE` lie2 `plusLIE` unitLIE enum_from_then) tcMonoExpr in_expr@(ArithSeqIn seq@(FromTo expr1 expr2)) res_ty = tcAddErrCtxt (arithSeqCtxt in_expr) $ - unifyListTy res_ty `thenTc` \ elt_ty -> - tcMonoExpr expr1 elt_ty `thenTc` \ (expr1',lie1) -> - tcMonoExpr expr2 elt_ty `thenTc` \ (expr2',lie2) -> - tcLookupGlobalValueByKey enumFromToClassOpKey `thenNF_Tc` \ sel_id -> - newMethod (ArithSeqOrigin seq) - (RealId sel_id) [elt_ty] `thenNF_Tc` \ (lie3, enum_from_to_id) -> + unifyListTy res_ty `thenTc` \ elt_ty -> + tcMonoExpr expr1 elt_ty `thenTc` \ (expr1',lie1) -> + tcMonoExpr expr2 elt_ty `thenTc` \ (expr2',lie2) -> + tcLookupGlobalId enumFromToName `thenNF_Tc` \ sel_id -> + newMethod (ArithSeqOrigin seq) sel_id [elt_ty] `thenNF_Tc` \ enum_from_to -> - returnTc (ArithSeqOut (HsVar enum_from_to_id) + returnTc (ArithSeqOut (HsVar (instToId enum_from_to)) (FromTo expr1' expr2'), - lie1 `plusLIE` lie2 `plusLIE` lie3) + lie1 `plusLIE` lie2 `plusLIE` unitLIE enum_from_to) tcMonoExpr in_expr@(ArithSeqIn seq@(FromThenTo expr1 expr2 expr3)) res_ty = tcAddErrCtxt (arithSeqCtxt in_expr) $ - unifyListTy res_ty `thenTc` \ elt_ty -> - tcMonoExpr expr1 elt_ty `thenTc` \ (expr1',lie1) -> - tcMonoExpr expr2 elt_ty `thenTc` \ (expr2',lie2) -> - tcMonoExpr expr3 elt_ty `thenTc` \ (expr3',lie3) -> - tcLookupGlobalValueByKey enumFromThenToClassOpKey `thenNF_Tc` \ sel_id -> - newMethod (ArithSeqOrigin seq) - (RealId sel_id) [elt_ty] `thenNF_Tc` \ (lie4, eft_id) -> - - returnTc (ArithSeqOut (HsVar eft_id) - (FromThenTo expr1' expr2' expr3'), - lie1 `plusLIE` lie2 `plusLIE` lie3 `plusLIE` lie4) + unifyListTy res_ty `thenTc` \ elt_ty -> + tcMonoExpr expr1 elt_ty `thenTc` \ (expr1',lie1) -> + tcMonoExpr expr2 elt_ty `thenTc` \ (expr2',lie2) -> + tcMonoExpr expr3 elt_ty `thenTc` \ (expr3',lie3) -> + tcLookupGlobalId enumFromThenToName `thenNF_Tc` \ sel_id -> + newMethod (ArithSeqOrigin seq) sel_id [elt_ty] `thenNF_Tc` \ eft -> + + returnTc (ArithSeqOut (HsVar (instToId eft)) + (FromThenTo expr1' expr2' expr3'), + lie1 `plusLIE` lie2 `plusLIE` lie3 `plusLIE` unitLIE eft) + +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) -> + tcLookupGlobalId enumFromToPName `thenNF_Tc` \ sel_id -> + newMethod (PArrSeqOrigin seq) sel_id [elt_ty] `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) -> + tcLookupGlobalId enumFromThenToPName `thenNF_Tc` \ sel_id -> + newMethod (PArrSeqOrigin seq) sel_id [elt_ty] `thenNF_Tc` \ eft -> + + returnTc (PArrSeqOut (HsVar (instToId eft)) + (FromThenTo expr1' expr2' expr3'), + lie1 `plusLIE` lie2 `plusLIE` lie3 `plusLIE` unitLIE eft) + +tcMonoExpr (PArrSeqIn _) _ + = panic "TcExpr.tcMonoExpr: Infinite parallel array!" + -- the parser shouldn't have generated it and the renamer shouldn't have + -- let it through \end{code} %************************************************************************ %* * -\subsection{Expressions type signatures} +\subsection{Implicit Parameter bindings} %* * %************************************************************************ \begin{code} -tcMonoExpr in_expr@(ExprWithTySig expr poly_ty) res_ty - = tcSetErrCtxt (exprSigCtxt in_expr) $ - tcHsTcType poly_ty `thenTc` \ sig_tc_ty -> - - if not (isForAllTy sig_tc_ty) then - -- Easy case - unifyTauTy sig_tc_ty res_ty `thenTc_` - tcMonoExpr expr sig_tc_ty - - else -- Signature is polymorphic - tcPolyExpr expr sig_tc_ty `thenTc` \ (_, _, expr, expr_ty, lie) -> - - -- Now match the signature type with res_ty. - -- We must not do this earlier, because res_ty might well - -- mention variables free in the environment, and we'd get - -- bogus complaints about not being able to for-all the - -- sig_tyvars - unifyTauTy res_ty expr_ty `thenTc_` - - -- If everything is ok, return the stuff unchanged, except for - -- the effect of any substutions etc. We simply discard the - -- result of the tcSimplifyAndCheck (inside tcPolyExpr), except for any default - -- resolution it may have done, which is recorded in the - -- substitution. - returnTc (expr, lie) -\end{code} +tcMonoExpr (HsWith expr binds) res_ty + = tcMonoExpr expr res_ty `thenTc` \ (expr', expr_lie) -> + mapAndUnzip3Tc tcIPBind binds `thenTc` \ (avail_ips, binds', bind_lies) -> -Typecheck expression which in most cases will be an Id. - -\begin{code} -tcExpr_id :: RenamedHsExpr - -> TcM s (TcExpr s, - LIE s, - TcType s) -tcExpr_id id_expr - = case id_expr of - HsVar name -> tcId name `thenNF_Tc` \ stuff -> - returnTc stuff - other -> newTyVarTy openTypeKind `thenNF_Tc` \ id_ty -> - tcMonoExpr id_expr id_ty `thenTc` \ (id_expr', lie_id) -> - returnTc (id_expr', lie_id, id_ty) + -- 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', 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) \end{code} %************************************************************************ @@ -691,10 +618,12 @@ tcExpr_id id_expr \begin{code} -tcApp :: RenamedHsExpr -> [RenamedHsExpr] -- Function and args - -> TcType s -- Expected result type of application - -> TcM s (TcExpr s, [TcExpr s], -- Translated fun and args - LIE s) +tcApp :: RenamedHsExpr -> [RenamedHsExpr] -- Function and args + -> TcType -- Expected result type of application + -> TcM (TcExpr, LIE) -- Translated fun and args + +tcApp (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 @@ -704,22 +633,20 @@ tcApp fun args res_ty split_fun_ty fun_ty (length args) ) `thenTc` \ (expected_arg_tys, actual_result_ty) -> - -- Unify with expected result before type-checking the args - -- This is when we might detect a too-few args situation - tcAddErrCtxtM (checkArgsCtxt fun args res_ty actual_result_ty) ( - unifyTauTy res_ty actual_result_ty - ) `thenTc_` - -- Now typecheck the args mapAndUnzipTc (tcArg fun) (zip3 args expected_arg_tys [1..]) `thenTc` \ (args', lie_args_s) -> - -- Check that the result type doesn't have any nested for-alls. - -- For example, a "build" on its own is no good; it must be applied to something. - checkTc (isTauTy actual_result_ty) - (lurkingRank2Err fun fun_ty) `thenTc_` + -- 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) + (tcSub res_ty actual_result_ty) `thenTc` \ (co_fn, lie_res) -> - returnTc (fun', args', lie_fun `plusLIE` plusLIEs lie_args_s) + returnTc (co_fn <$> foldl HsApp fun' args', + lie_res `plusLIE` lie_fun `plusLIE` plusLIEs lie_args_s) -- If an error happens we try to figure out whether the @@ -729,22 +656,25 @@ checkArgsCtxt fun args expected_res_ty actual_res_ty tidy_env = zonkTcType expected_res_ty `thenNF_Tc` \ exp_ty' -> zonkTcType actual_res_ty `thenNF_Tc` \ act_ty' -> let - (env1, exp_ty'') = tidyType tidy_env exp_ty' - (env2, act_ty'') = tidyType env1 act_ty' - (exp_args, _) = splitFunTys exp_ty'' - (act_args, _) = splitFunTys act_ty'' - - message | length exp_args < length act_args = wrongArgsCtxt "too few" fun args - | length exp_args > length act_args = wrongArgsCtxt "too many" fun args - | otherwise = appCtxt fun args + (env1, exp_ty'') = tidyOpenType tidy_env exp_ty' + (env2, act_ty'') = tidyOpenType env1 act_ty' + (exp_args, _) = tcSplitFunTys exp_ty'' + (act_args, _) = tcSplitFunTys act_ty'' + + len_act_args = length act_args + len_exp_args = length exp_args + + message | len_exp_args < len_act_args = wrongArgsCtxt "too few" fun args + | len_exp_args > len_act_args = wrongArgsCtxt "too many" fun args + | otherwise = appCtxt fun args in returnNF_Tc (env2, message) -split_fun_ty :: TcType s -- The type of the function - -> Int -- Number of arguments - -> TcM s ([TcType s], -- Function argument types - TcType s) -- Function result types +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) @@ -757,9 +687,9 @@ split_fun_ty fun_ty n \end{code} \begin{code} -tcArg :: RenamedHsExpr -- The function (for error messages) - -> (RenamedHsExpr, TcType s, Int) -- Actual argument and expected arg type - -> TcM s (TcExpr s, LIE s) -- Resulting argument and LIE +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) $ @@ -774,45 +704,23 @@ tcArg the_fun (arg, expected_arg_ty, arg_no) %************************************************************************ \begin{code} -tcId :: Name -> NF_TcM s (TcExpr s, LIE s, TcType s) - -tcId name - = -- Look up the Id and instantiate its type - tcLookupLocalValue name `thenNF_Tc` \ maybe_local -> - - case maybe_local of - Just tc_id -> instantiate_it (TcId tc_id) (idType tc_id) +tcId :: Name -> NF_TcM (TcExpr, LIE, TcType) +tcId name -- Look up the Id and instantiate its type + = tcLookupId name `thenNF_Tc` \ id -> + tcInstId id +\end{code} - Nothing -> tcLookupGlobalValue name `thenNF_Tc` \ id -> - tcInstId id `thenNF_Tc` \ (tyvars, theta, tau) -> - instantiate_it2 (RealId id) tyvars theta tau +Typecheck expression which in most cases will be an Id. - where - -- The instantiate_it loop runs round instantiating the Id. - -- It has to be a loop because we are now prepared to entertain - -- types like - -- f:: forall a. Eq a => forall b. Baz b => tau - -- We want to instantiate this to - -- f2::tau {f2 = f1 b (Baz b), f1 = f a (Eq a)} - instantiate_it tc_id_occ ty - = tcInstTcType ty `thenNF_Tc` \ (tyvars, rho) -> - tcSplitRhoTy rho `thenNF_Tc` \ (theta, tau) -> - instantiate_it2 tc_id_occ tyvars theta tau - - instantiate_it2 tc_id_occ tyvars theta tau - = if null theta then -- Is it overloaded? - returnNF_Tc (mkHsTyApp (HsVar tc_id_occ) arg_tys, emptyLIE, tau) - else - -- Yes, it's overloaded - newMethodWithGivenTy (OccurrenceOf tc_id_occ) - tc_id_occ arg_tys theta tau `thenNF_Tc` \ inst -> - instantiate_it (instToId inst) tau `thenNF_Tc` \ (expr, lie2, final_tau) -> - returnNF_Tc (expr, unitLIE inst `plusLIE` lie2, final_tau) - - where - arg_tys = mkTyVarTys tyvars +\begin{code} +tcExpr_id :: RenamedHsExpr -> TcM (TcExpr, LIE, TcType) +tcExpr_id (HsVar name) = tcId name +tcExpr_id expr = newTyVarTy openTypeKind `thenNF_Tc` \ id_ty -> + tcMonoExpr expr id_ty `thenTc` \ (expr', lie_id) -> + returnTc (expr', lie_id, id_ty) \end{code} + %************************************************************************ %* * \subsection{@tcDoStmts@ typechecks a {\em list} of do statements} @@ -820,17 +728,51 @@ tcId name %************************************************************************ \begin{code} +-- I don't like this lumping together of do expression and list/array +-- comprehensions; creating the monad instances is entirely pointless in the +-- latter case; I'll leave the list case as it is for the moment, but handle +-- arrays extra (would be better to handle arrays and lists together, though) +-- -=chak +-- +tcDoStmts PArrComp stmts src_loc res_ty + = + ASSERT( not (null stmts) ) + tcAddSrcLoc src_loc $ + + unifyPArrTy res_ty `thenTc` \elt_ty -> + let tc_ty = mkTyConTy parrTyCon + m_ty = (mkPArrTy, elt_ty) + in + tcStmts (DoCtxt PArrComp) m_ty stmts `thenTc` \(stmts', stmts_lie) -> + returnTc (HsDoOut PArrComp stmts' + undefined undefined undefined -- don't touch! + res_ty src_loc, + stmts_lie) + tcDoStmts do_or_lc stmts src_loc res_ty = -- get the Monad and MonadZero classes -- create type consisting of a fresh monad tyvar ASSERT( not (null stmts) ) tcAddSrcLoc src_loc $ - newTyVarTy (mkArrowKind boxedTypeKind boxedTypeKind) `thenNF_Tc` \ m -> - newTyVarTy boxedTypeKind `thenNF_Tc` \ elt_ty -> - unifyTauTy res_ty (mkAppTy m elt_ty) `thenTc_` + -- If it's a comprehension we're dealing with, + -- force it to be a list comprehension. + -- (as of Haskell 98, monad comprehensions are no more.) + -- Similarily, array comprehensions must involve parallel arrays types + -- -=chak + (case do_or_lc of + ListComp -> unifyListTy res_ty `thenTc` \ elt_ty -> + returnNF_Tc (mkTyConTy listTyCon, (mkListTy, elt_ty)) + + PArrComp -> panic "TcExpr.tcDoStmts: How did we get here?!?" + + _ -> newTyVarTy (mkArrowKind liftedTypeKind liftedTypeKind) `thenNF_Tc` \ m_ty -> + newTyVarTy liftedTypeKind `thenNF_Tc` \ elt_ty -> + unifyTauTy res_ty (mkAppTy m_ty elt_ty) `thenTc_` + returnNF_Tc (m_ty, (mkAppTy m_ty, elt_ty)) + ) `thenNF_Tc` \ (tc_ty, m_ty) -> - tcStmts do_or_lc (mkAppTy m) stmts elt_ty `thenTc` \ (stmts', stmts_lie) -> + tcStmts (DoCtxt do_or_lc) m_ty stmts `thenTc` \ (stmts', stmts_lie) -> -- Build the then and zero methods in case we need them -- It's important that "then" and "return" appear just once in the final LIE, @@ -840,25 +782,18 @@ tcDoStmts do_or_lc stmts src_loc res_ty -- then = then -- where the second "then" sees that it already exists in the "available" stuff. -- - tcLookupGlobalValueByKey returnMClassOpKey `thenNF_Tc` \ return_sel_id -> - tcLookupGlobalValueByKey thenMClassOpKey `thenNF_Tc` \ then_sel_id -> - tcLookupGlobalValueByKey zeroClassOpKey `thenNF_Tc` \ zero_sel_id -> - newMethod DoOrigin - (RealId return_sel_id) [m] `thenNF_Tc` \ (return_lie, return_id) -> - newMethod DoOrigin - (RealId then_sel_id) [m] `thenNF_Tc` \ (then_lie, then_id) -> - newMethod DoOrigin - (RealId zero_sel_id) [m] `thenNF_Tc` \ (zero_lie, zero_id) -> + tcLookupGlobalId returnMName `thenNF_Tc` \ return_sel_id -> + tcLookupGlobalId thenMName `thenNF_Tc` \ then_sel_id -> + tcLookupGlobalId failMName `thenNF_Tc` \ fail_sel_id -> + newMethod DoOrigin return_sel_id [tc_ty] `thenNF_Tc` \ return_inst -> + newMethod DoOrigin then_sel_id [tc_ty] `thenNF_Tc` \ then_inst -> + newMethod DoOrigin fail_sel_id [tc_ty] `thenNF_Tc` \ fail_inst -> let - monad_lie = then_lie `plusLIE` return_lie `plusLIE` perhaps_zero_lie - perhaps_zero_lie | all failure_free stmts' = emptyLIE - | otherwise = zero_lie - - failure_free (BindStmt pat _ _) = failureFreePat pat - failure_free (GuardStmt _ _) = False - failure_free other_stmt = True + monad_lie = mkLIE [return_inst, then_inst, fail_inst] in - returnTc (HsDoOut do_or_lc stmts' return_id then_id zero_id res_ty src_loc, + returnTc (HsDoOut do_or_lc stmts' + (instToId return_inst) (instToId then_inst) (instToId fail_inst) + res_ty src_loc, stmts_lie `plusLIE` monad_lie) \end{code} @@ -871,55 +806,51 @@ tcDoStmts do_or_lc stmts src_loc res_ty Game plan for record bindings ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -For each binding - field = value -1. look up "field", to find its selector Id, which must have type - forall a1..an. T a1 .. an -> tau - where tau is the type of the field. +1. Find the TyCon for the bindings, from the first field label. + +2. Instantiate its tyvars and unify (T a1 .. an) with expected_ty. -2. Instantiate this type +For each binding field = value -3. Unify the (T a1 .. an) part with the "expected result type", which - is passed in. This checks that all the field labels come from the - same type. +3. Instantiate the field type (from the field label) using the type + envt from step 2. -4. Type check the value using tcArg, passing tau as the expected - argument type. +4 Type check the value using tcArg, passing the field type as + the expected argument type. This extends OK when the field types are universally quantified. -Actually, to save excessive creation of fresh type variables, -we \begin{code} tcRecordBinds - :: TcType s -- Expected type of whole record + :: TyCon -- Type constructor for the record + -> [TcType] -- Args of this type constructor -> RenamedRecordBinds - -> TcM s (TcRecordBinds s, LIE s) + -> TcM (TcRecordBinds, LIE) -tcRecordBinds expected_record_ty rbinds +tcRecordBinds tycon ty_args rbinds = mapAndUnzipTc do_bind rbinds `thenTc` \ (rbinds', lies) -> returnTc (rbinds', plusLIEs lies) where - do_bind (field_label, rhs, pun_flag) - = tcLookupGlobalValue field_label `thenNF_Tc` \ sel_id -> + tenv = mkTopTyVarSubst (tyConTyVars tycon) ty_args + + do_bind (field_lbl_name, rhs, pun_flag) + = tcLookupGlobalId field_lbl_name `thenNF_Tc` \ sel_id -> + let + field_lbl = recordSelectorFieldLabel sel_id + field_ty = substTy tenv (fieldLabelType field_lbl) + in ASSERT( isRecordSelector sel_id ) -- This lookup and assertion will surely succeed, because -- we check that the fields are indeed record selectors -- before calling tcRecordBinds + ASSERT2( fieldLabelTyCon field_lbl == tycon, ppr field_lbl ) + -- The caller of tcRecordBinds has already checked + -- that all the fields come from the same type - tcInstId sel_id `thenNF_Tc` \ (_, _, tau) -> + tcExpr rhs field_ty `thenTc` \ (rhs', lie) -> - -- Record selectors all have type - -- forall a1..an. T a1 .. an -> tau - ASSERT( maybeToBool (splitFunTy_maybe tau) ) - let - -- Selector must have type RecordType -> FieldType - Just (record_ty, field_ty) = splitFunTy_maybe tau - in - unifyTauTy expected_record_ty record_ty `thenTc_` - tcPolyExpr rhs field_ty `thenTc` \ (rhs', lie, _, _, _) -> - returnTc ((RealId sel_id, rhs', pun_flag), lie) + returnTc ((sel_id, rhs', pun_flag), lie) badFields rbinds data_con = [field_name | (field_name, _, _) <- rbinds, @@ -927,6 +858,33 @@ badFields rbinds data_con ] where field_names = map fieldLabelName (dataConFieldLabels data_con) + +missingFields rbinds data_con + | null field_labels = ([], []) -- Not declared as a record; + -- But C{} is still valid + | otherwise + = (missing_strict_fields, other_missing_fields) + where + missing_strict_fields + = [ fl | (fl, str) <- field_info, + isMarkedStrict str, + not (fieldLabelName fl `elem` field_names_used) + ] + other_missing_fields + = [ fl | (fl, str) <- field_info, + not (isMarkedStrict str), + not (fieldLabelName fl `elem` field_names_used) + ] + + field_names_used = [ field_name | (field_name, _, _) <- rbinds ] + field_labels = dataConFieldLabels data_con + + field_info = zipEqual "missingFields" + field_labels + (dropList ex_theta (dataConStrictMarks data_con)) + -- The 'drop' is because dataConStrictMarks + -- includes the existential dictionaries + (_, _, _, ex_theta, _, _) = dataConSig data_con \end{code} %************************************************************************ @@ -936,7 +894,7 @@ badFields rbinds data_con %************************************************************************ \begin{code} -tcMonoExprs :: [RenamedHsExpr] -> [TcType s] -> TcM s ([TcExpr s], LIE s) +tcMonoExprs :: [RenamedHsExpr] -> [TcType] -> TcM ([TcExpr], LIE) tcMonoExprs [] [] = returnTc ([], emptyLIE) tcMonoExprs (expr:exprs) (ty:tys) @@ -946,22 +904,44 @@ tcMonoExprs (expr:exprs) (ty:tys) \end{code} -% ================================================= +%************************************************************************ +%* * +\subsection{Literals} +%* * +%************************************************************************ -Errors and contexts -~~~~~~~~~~~~~~~~~~~ +Overloaded literals. -Mini-utils: \begin{code} -pp_nest_hang :: String -> SDoc -> SDoc -pp_nest_hang label stuff = nest 2 (hang (text label) 4 stuff) +tcLit :: HsLit -> TcType -> TcM (TcExpr, LIE) +tcLit (HsLitLit s _) res_ty + = tcLookupClass cCallableClassName `thenNF_Tc` \ cCallableClass -> + newDicts (LitLitOrigin (_UNPK_ s)) + [mkClassPred cCallableClass [res_ty]] `thenNF_Tc` \ dicts -> + returnTc (HsLit (HsLitLit s res_ty), mkLIE dicts) + +tcLit lit res_ty + = unifyTauTy res_ty (simpleHsLitTy lit) `thenTc_` + returnTc (HsLit lit, emptyLIE) \end{code} + +%************************************************************************ +%* * +\subsection{Errors and contexts} +%* * +%************************************************************************ + +Mini-utils: + Boring and alphabetical: \begin{code} arithSeqCtxt expr = hang (ptext SLIT("In an arithmetic sequence:")) 4 (ppr expr) +parrSeqCtxt expr + = hang (ptext SLIT("In a parallel array sequence:")) 4 (ppr expr) + caseCtxt expr = hang (ptext SLIT("In the case expression:")) 4 (ppr expr) @@ -975,14 +955,14 @@ exprSigCtxt expr listCtxt expr = hang (ptext SLIT("In the list element:")) 4 (ppr expr) +parrCtxt expr + = hang (ptext SLIT("In the parallel array element:")) 4 (ppr expr) + predCtxt expr = hang (ptext SLIT("In the predicate expression:")) 4 (ppr expr) -sectionRAppCtxt expr - = hang (ptext SLIT("In the right section:")) 4 (ppr expr) - -sectionLAppCtxt expr - = hang (ptext SLIT("In the left section:")) 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"), @@ -998,17 +978,14 @@ wrongArgsCtxt too_many_or_few fun args the_app = foldl HsApp fun args -- Used in error messages appCtxt fun args - = ptext SLIT("In the application") <+> (ppr the_app) + = ptext SLIT("In the application") <+> quotes (ppr the_app) where the_app = foldl HsApp fun args -- Used in error messages lurkingRank2Err fun fun_ty = hang (hsep [ptext SLIT("Illegal use of"), quotes (ppr fun)]) 4 (vcat [ptext SLIT("It is applied to too few arguments"), - ptext SLIT("so that the result type has for-alls in it")]) - -rank2ArgCtxt arg expected_arg_ty - = ptext SLIT("In a polymorphic function argument:") <+> ppr arg + ptext SLIT("so that the result type has for-alls in it:") <+> ppr fun_ty]) badFieldsUpd rbinds = hang (ptext SLIT("No constructor has all these fields:")) @@ -1016,8 +993,19 @@ badFieldsUpd rbinds where fields = [field | (field, _, _) <- rbinds] -recordUpdCtxt = ptext SLIT("In a record update construct") +recordUpdCtxt expr = ptext SLIT("In the record update:") <+> ppr expr +recordConCtxt expr = ptext SLIT("In the record construction:") <+> ppr expr notSelector field = hsep [quotes (ppr field), ptext SLIT("is not a record selector")] + +missingStrictFieldCon :: Name -> FieldLabel -> SDoc +missingStrictFieldCon con field + = hsep [ptext SLIT("Constructor") <+> quotes (ppr con), + ptext SLIT("does not have the required strict field"), quotes (ppr field)] + +missingFieldCon :: Name -> FieldLabel -> SDoc +missingFieldCon con field + = hsep [ptext SLIT("Field") <+> quotes (ppr field), + ptext SLIT("is not initialised")] \end{code}