X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Fcompiler%2Ftypecheck%2FTcExpr.lhs;h=56fc0e37a6582775da321dad9cd56a1a1f319413;hb=10fcd78ccde892feccda3f5eacd221c1de75feea;hp=65738ee6f9b0b12aeb9f55c7a966b2323802cc93;hpb=8de16184643ea3c2f9f30b5eaed18db6ef247760;p=ghc-hetmet.git diff --git a/ghc/compiler/typecheck/TcExpr.lhs b/ghc/compiler/typecheck/TcExpr.lhs index 65738ee..56fc0e3 100644 --- a/ghc/compiler/typecheck/TcExpr.lhs +++ b/ghc/compiler/typecheck/TcExpr.lhs @@ -1,168 +1,140 @@ % -% (c) The GRASP/AQUA Project, Glasgow University, 1992-1996 +% (c) The GRASP/AQUA Project, Glasgow University, 1992-1998 % \section[TcExpr]{Typecheck an expression} \begin{code} -#include "HsVersions.h" - -module TcExpr ( tcExpr, tcId ) where +module TcExpr ( tcExpr, tcMonoExpr, tcId ) where -IMP_Ubiq() +#include "HsVersions.h" -import HsSyn ( HsExpr(..), Qualifier(..), Stmt(..), - HsBinds(..), Bind(..), MonoBinds(..), - ArithSeqInfo(..), HsLit(..), Sig, GRHSsAndBinds, - Match, Fake, InPat, OutPat, HsType, Fixity, - pprParendExpr, failureFreePat, collectPatBinders ) -import RnHsSyn ( SYN_IE(RenamedHsExpr), SYN_IE(RenamedQual), - SYN_IE(RenamedStmt), SYN_IE(RenamedRecordBinds) - ) -import TcHsSyn ( SYN_IE(TcExpr), SYN_IE(TcQual), SYN_IE(TcStmt), - TcIdOcc(..), SYN_IE(TcRecordBinds), - mkHsTyApp +import HsSyn ( HsExpr(..), HsLit(..), ArithSeqInfo(..), + HsMatchContext(..), HsDoContext(..), mkMonoBind ) +import RnHsSyn ( RenamedHsExpr, RenamedRecordBinds ) +import TcHsSyn ( TcExpr, TcRecordBinds, simpleHsLitTy ) import TcMonad -import Inst ( Inst, InstOrigin(..), OverloadedLit(..), - SYN_IE(LIE), emptyLIE, plusLIE, plusLIEs, newOverloadedLit, - newMethod, newMethodWithGivenTy, newDicts ) -import TcBinds ( tcBindsAndThen ) -import TcEnv ( tcLookupLocalValue, tcLookupGlobalValue, tcLookupClassByKey, - tcLookupGlobalValueByKey, newMonoIds, tcGetGlobalTyVars, - tcExtendGlobalTyVars +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 SpecEnv ( SpecEnv ) -import TcMatches ( tcMatchesCase, tcMatch ) -import TcMonoType ( tcHsType ) -import TcPat ( tcPat ) -import TcSimplify ( tcSimplifyAndCheck, tcSimplifyRank2 ) -import TcType ( SYN_IE(TcType), TcMaybe(..), - tcInstId, tcInstType, tcInstSigTcType, - tcInstSigType, tcInstTcType, tcInstTheta, - newTyVarTy, zonkTcTyVars, zonkTcType ) -import TcKind ( TcKind ) - -import Class ( SYN_IE(Class), classSig ) -import FieldLabel ( fieldLabelName ) -import Id ( idType, dataConFieldLabels, dataConSig, SYN_IE(Id), GenId ) -import Kind ( Kind, mkBoxedTypeKind, mkTypeKind, mkArrowKind ) -import GenSpecEtc ( checkSigTyVars ) -import Name ( Name{-instance Eq-} ) -import Type ( mkFunTy, mkAppTy, mkTyVarTy, mkTyVarTys, mkRhoTy, - getTyVar_maybe, getFunTy_maybe, instantiateTy, - splitForAllTy, splitRhoTy, splitSigmaTy, splitFunTy, - isTauTy, mkFunTys, tyVarsOfType, getForAllTy_maybe, - getAppDataTyCon, maybeAppDataTyCon +import TcBinds ( tcBindsAndThen ) +import TcEnv ( tcLookupClass, tcLookupGlobalId, tcLookupGlobal_maybe, + tcLookupTyCon, tcLookupDataCon, tcLookupId ) -import TyVar ( GenTyVar, SYN_IE(TyVarSet), unionTyVarSets, mkTyVarSet ) -import TysPrim ( intPrimTy, charPrimTy, doublePrimTy, - floatPrimTy, addrPrimTy, realWorldTy +import TcMatches ( tcMatchesCase, tcMatchLambda, tcStmts ) +import TcMonoType ( tcHsSigType, UserTypeCtxt(..) ) +import TcPat ( badFieldCon ) +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 TysWiredIn ( addrTy, - boolTy, charTy, stringTy, mkListTy, - mkTupleTy, mkPrimIoTy, stDataCon +import FieldLabel ( FieldLabel, fieldLabelName, fieldLabelType, fieldLabelTyCon ) +import Id ( idType, recordSelectorFieldLabel, isRecordSelector ) +import DataCon ( dataConFieldLabels, dataConSig, + dataConStrictMarks ) -import Unify ( unifyTauTy, unifyTauTyList, unifyTauTyLists, unifyFunTy ) -import Unique ( Unique, cCallableClassKey, cReturnableClassKey, - enumFromClassOpKey, enumFromThenClassOpKey, - enumFromToClassOpKey, enumFromThenToClassOpKey, - thenMClassOpKey, zeroClassOpKey +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 ( interpp'SP ) -import PprType ( GenType, GenTyVar ) -- Instances -import Maybes ( maybeToBool ) -import Pretty +import Outputable +import ListSetOps ( minusList ) import Util -\end{code} +import CmdLineOpts +import HscTypes ( TyThing(..) ) -\begin{code} -tcExpr :: RenamedHsExpr -> TcM s (TcExpr s, LIE s, TcType s) \end{code} %************************************************************************ %* * -\subsection{The TAUT rules for variables} +\subsection{Main wrappers} %* * %************************************************************************ \begin{code} -tcExpr (HsVar name) - = tcId name `thenNF_Tc` \ (expr', lie, res_ty) -> +tcExpr :: RenamedHsExpr -- Expession to type check + -> TcSigmaType -- Expected type (could be a polytpye) + -> TcM (TcExpr, LIE) -- Generalised expr with expected type, and LIE - -- 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 res_ty) - (lurkingRank2Err name res_ty) `thenTc_` +tcExpr expr expected_ty + | not (isSigmaTy expected_ty) -- Monomorphic case + = tcMonoExpr expr expected_ty - returnTc (expr', lie, res_ty) + | otherwise + = tcGen expected_ty (tcMonoExpr expr) `thenTc` \ (gen_fn, expr', lie) -> + returnTc (gen_fn <$> expr', lie) \end{code} + %************************************************************************ %* * -\subsection{Literals} +\subsection{The TAUT rules for variables} %* * %************************************************************************ -Overloaded literals. - \begin{code} -tcExpr (HsLit (HsInt i)) - = newTyVarTy mkBoxedTypeKind `thenNF_Tc` \ ty -> - - newOverloadedLit (LiteralOrigin (HsInt i)) - (OverloadedIntegral i) - ty `thenNF_Tc` \ (lie, over_lit_id) -> - - returnTc (HsVar over_lit_id, lie, ty) - -tcExpr (HsLit (HsFrac f)) - = newTyVarTy mkBoxedTypeKind `thenNF_Tc` \ ty -> - - newOverloadedLit (LiteralOrigin (HsFrac f)) - (OverloadedFractional f) - ty `thenNF_Tc` \ (lie, over_lit_id) -> - - returnTc (HsVar over_lit_id, lie, ty) - -tcExpr (HsLit lit@(HsLitLit s)) - = tcLookupClassByKey cCallableClassKey `thenNF_Tc` \ cCallableClass -> - newTyVarTy mkBoxedTypeKind `thenNF_Tc` \ ty -> - newDicts (LitLitOrigin (_UNPK_ s)) - [(cCallableClass, ty)] `thenNF_Tc` \ (dicts, _) -> - returnTc (HsLitOut lit ty, dicts, ty) +tcMonoExpr :: RenamedHsExpr -- Expession to type check + -> 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', 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} -Primitive literals: -\begin{code} -tcExpr (HsLit lit@(HsCharPrim c)) - = returnTc (HsLitOut lit charPrimTy, emptyLIE, charPrimTy) - -tcExpr (HsLit lit@(HsStringPrim s)) - = returnTc (HsLitOut lit addrPrimTy, emptyLIE, addrPrimTy) - -tcExpr (HsLit lit@(HsIntPrim i)) - = returnTc (HsLitOut lit intPrimTy, emptyLIE, intPrimTy) - -tcExpr (HsLit lit@(HsFloatPrim f)) - = returnTc (HsLitOut lit floatPrimTy, emptyLIE, floatPrimTy) - -tcExpr (HsLit lit@(HsDoublePrim d)) - = returnTc (HsLitOut lit doublePrimTy, emptyLIE, doublePrimTy) -\end{code} - -Unoverloaded literals: +%************************************************************************ +%* * +\subsection{Expressions type signatures} +%* * +%************************************************************************ \begin{code} -tcExpr (HsLit lit@(HsChar c)) - = returnTc (HsLitOut lit charTy, emptyLIE, charTy) - -tcExpr (HsLit lit@(HsString str)) - = returnTc (HsLitOut lit stringTy, emptyLIE, stringTy) +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} + %************************************************************************ %* * \subsection{Other expression forms} @@ -170,26 +142,19 @@ tcExpr (HsLit lit@(HsString str)) %************************************************************************ \begin{code} -tcExpr (HsPar expr) -- preserve parens so printing needn't guess where they go - = tcExpr expr - -tcExpr (NegApp expr neg) = tcExpr (HsApp neg expr) +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 -tcExpr (HsLam match) - = tcMatch match `thenTc` \ (match',lie,ty) -> - returnTc (HsLam match', lie, ty) +tcMonoExpr (NegApp expr neg_name) res_ty + = tcMonoExpr (HsApp (HsVar neg_name) expr) res_ty -tcExpr (HsApp e1 e2) = accum e1 [e2] - where - accum (HsApp e1 e2) args = accum e1 (e2:args) - accum fun args - = tcApp fun args `thenTc` \ (fun', args', lie, res_ty) -> - returnTc (foldl HsApp fun' args', lie, res_ty) +tcMonoExpr (HsLam match) res_ty + = tcMatchLambda match res_ty `thenTc` \ (match',lie) -> + returnTc (HsLam match', lie) --- equivalent to (op e1) e2: -tcExpr (OpApp arg1 op fix arg2) - = tcApp op [arg1,arg2] `thenTc` \ (op', [arg1', arg2'], lie, res_ty) -> - returnTc (OpApp arg1' op' fix arg2', lie, res_ty) +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 @@ -203,35 +168,36 @@ a type error will occur if they aren't. -- or just -- op e -tcExpr in_expr@(SectionL arg op) - = tcApp op [arg] `thenTc` \ (op', [arg'], lie, res_ty) -> - - -- 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! - newTyVarTy mkTypeKind `thenNF_Tc` \ ty1 -> - newTyVarTy mkTypeKind `thenNF_Tc` \ ty2 -> - tcAddErrCtxt (sectionLAppCtxt in_expr) $ - unifyTauTy (mkFunTy ty1 ty2) res_ty `thenTc_` - - returnTc (SectionL arg' op', lie, res_ty) +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 -tcExpr in_expr@(SectionR op expr) - = tcExpr op `thenTc` \ (op', lie1, op_ty) -> - tcExpr expr `thenTc` \ (expr',lie2, expr_ty) -> +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) - newTyVarTy mkTypeKind `thenNF_Tc` \ ty1 -> - newTyVarTy mkTypeKind `thenNF_Tc` \ ty2 -> - tcAddErrCtxt (sectionRAppCtxt in_expr) $ - unifyTauTy (mkFunTys [ty1, expr_ty] ty2) op_ty `thenTc_` +-- equivalent to (op e1) e2: - returnTc (SectionR op' expr', lie1 `plusLIE` lie2, mkFunTy ty1 ty2) +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 @@ -242,252 +208,406 @@ arg/result types); unify them with the args/result; and store them for later use. \begin{code} -tcExpr (CCall lbl args may_gc is_asm ignored_fake_result_ty) - = -- Get the callable and returnable classes. - tcLookupClassByKey cCallableClassKey `thenNF_Tc` \ cCallableClass -> - tcLookupClassByKey cReturnableClassKey `thenNF_Tc` \ cReturnableClass -> +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 - tcExprs args `thenTc` \ (args', args_lie, arg_tys) -> + 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 PrimIO + -- The argument types can be unlifted or lifted; the result + -- type must, however, be lifted since it's an argument to the IO -- type constructor. - newTyVarTy mkBoxedTypeKind `thenNF_Tc` \ result_ty -> + newTyVarTy liftedTypeKind `thenNF_Tc` \ result_ty -> + let + io_result_ty = mkTyConApp ioTyCon [result_ty] + in + 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 "tcExpr:CCall" args arg_tys) `thenNF_Tc` \ ccarg_dicts_s -> - newDicts result_origin [(cReturnableClass, result_ty)] `thenNF_Tc` \ (ccres_dict, _) -> - - returnTc (HsApp (HsVar (RealId stDataCon) `TyApp` [realWorldTy, 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, - mkPrimIoTy result_ty) + 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} -tcExpr (HsSCC label expr) - = tcExpr expr `thenTc` \ (expr', lie, expr_ty) -> - -- No unification. Give SCC the type of expr - returnTc (HsSCC label expr', lie, expr_ty) +tcMonoExpr (HsSCC lbl expr) res_ty + = tcMonoExpr expr res_ty `thenTc` \ (expr', lie) -> + returnTc (HsSCC lbl expr', lie) -tcExpr (HsLet binds expr) +tcMonoExpr (HsLet binds expr) res_ty = tcBindsAndThen - HsLet -- The combiner + combiner binds -- Bindings to check - (tcExpr expr) -- Typechecker for the expression - -tcExpr in_expr@(HsCase expr matches src_loc) - = tcAddSrcLoc src_loc $ - tcExpr expr `thenTc` \ (expr',lie1,expr_ty) -> - newTyVarTy mkTypeKind `thenNF_Tc` \ result_ty -> - - tcAddErrCtxt (caseCtxt in_expr) $ - tcMatchesCase (mkFunTy expr_ty result_ty) matches - `thenTc` \ (matches',lie2) -> - - returnTc (HsCase expr' matches' src_loc, plusLIE lie1 lie2, result_ty) - -tcExpr (HsIf pred b1 b2 src_loc) + tc_expr `thenTc` \ (expr', lie) -> + returnTc (expr', lie) + where + tc_expr = tcMonoExpr expr res_ty `thenTc` \ (expr', lie) -> + returnTc (expr', lie) + combiner is_rec bind expr = HsLet (mkMonoBind bind [] is_rec) expr + +tcMonoExpr in_expr@(HsCase scrut matches src_loc) res_ty + = tcAddSrcLoc src_loc $ + tcAddErrCtxt (caseCtxt in_expr) $ + + -- Typecheck the case alternatives first. + -- The case patterns tend to give good type info to use + -- when typechecking the scrutinee. For example + -- case (map f) of + -- (x:xs) -> ... + -- will report that map is applied to too few arguments + -- + -- Not only that, but it's better to check the matches on their + -- own, so that we get the expected results for scoped type variables. + -- f x = case x of + -- (p::a, q::b) -> (q,p) + -- The above should work: the match (p,q) -> (q,p) is polymorphic as + -- claimed by the pattern signatures. But if we typechecked the + -- match with x in scope and x's type as the expected type, we'd be hosed. + + tcMatchesCase matches res_ty `thenTc` \ (scrut_ty, matches', lie2) -> + + tcAddErrCtxt (caseScrutCtxt scrut) ( + tcMonoExpr scrut scrut_ty + ) `thenTc` \ (scrut',lie1) -> + + returnTc (HsCase scrut' matches' src_loc, plusLIE lie1 lie2) + +tcMonoExpr (HsIf pred b1 b2 src_loc) res_ty = tcAddSrcLoc src_loc $ - tcExpr pred `thenTc` \ (pred',lie1,predTy) -> - tcAddErrCtxt (predCtxt pred) ( - unifyTauTy boolTy predTy - ) `thenTc_` - - tcExpr b1 `thenTc` \ (b1',lie2,result_ty) -> - tcExpr b2 `thenTc` \ (b2',lie3,b2Ty) -> - - tcAddErrCtxt (branchCtxt b1 b2) $ - unifyTauTy result_ty b2Ty `thenTc_` + tcMonoExpr pred boolTy ) `thenTc` \ (pred',lie1) -> - returnTc (HsIf pred' b1' b2' src_loc, plusLIE lie1 (plusLIE lie2 lie3), result_ty) - -tcExpr (ListComp expr quals) - = tcListComp expr quals `thenTc` \ ((expr',quals'), lie, ty) -> - returnTc (ListComp expr' quals', lie, ty) + tcMonoExpr b1 res_ty `thenTc` \ (b1',lie2) -> + tcMonoExpr b2 res_ty `thenTc` \ (b2',lie3) -> + returnTc (HsIf pred' b1' b2' src_loc, plusLIE lie1 (plusLIE lie2 lie3)) \end{code} \begin{code} -tcExpr expr@(HsDo stmts src_loc) - = tcDoStmts stmts src_loc +tcMonoExpr expr@(HsDo do_or_lc stmts src_loc) res_ty + = tcDoStmts do_or_lc stmts src_loc res_ty \end{code} \begin{code} -tcExpr (ExplicitList []) - = newTyVarTy mkBoxedTypeKind `thenNF_Tc` \ tyvar_ty -> - returnTc (ExplicitListOut tyvar_ty [], emptyLIE, mkListTy tyvar_ty) - - -tcExpr in_expr@(ExplicitList exprs) -- Non-empty list - = tcExprs exprs `thenTc` \ (exprs', lie, tys@(elt_ty:_)) -> - tcAddErrCtxt (listCtxt in_expr) $ - unifyTauTyList tys `thenTc_` - returnTc (ExplicitListOut elt_ty exprs', lie, mkListTy elt_ty) - -tcExpr (ExplicitTuple exprs) - = tcExprs exprs `thenTc` \ (exprs', lie, tys) -> - returnTc (ExplicitTuple exprs', lie, mkTupleTy (length tys) tys) - -tcExpr (RecordCon (HsVar con) rbinds) - = tcId con `thenNF_Tc` \ (con_expr, con_lie, con_tau) -> +tcMonoExpr in_expr@(ExplicitList _ exprs) res_ty -- Non-empty list + = unifyListTy res_ty `thenTc` \ elt_ty -> + mapAndUnzipTc (tc_elt elt_ty) exprs `thenTc` \ (exprs', lies) -> + returnTc (ExplicitList elt_ty exprs', plusLIEs lies) + where + tc_elt elt_ty expr + = tcAddErrCtxt (listCtxt expr) $ + tcMonoExpr expr elt_ty + +tcMonoExpr in_expr@(ExplicitPArr _ exprs) res_ty -- maybe empty + = unifyPArrTy res_ty `thenTc` \ elt_ty -> + mapAndUnzipTc (tc_elt elt_ty) exprs `thenTc` \ (exprs', lies) -> + returnTc (ExplicitPArr elt_ty exprs', plusLIEs lies) + where + tc_elt elt_ty expr + = tcAddErrCtxt (parrCtxt expr) $ + tcMonoExpr expr elt_ty + +tcMonoExpr (ExplicitTuple exprs boxity) res_ty + = unifyTupleTy boxity (length exprs) res_ty `thenTc` \ arg_tys -> + mapAndUnzipTc (\ (expr, arg_ty) -> tcMonoExpr expr arg_ty) + (exprs `zip` arg_tys) -- we know they're of equal length. + `thenTc` \ (exprs', lies) -> + returnTc (ExplicitTuple exprs' boxity, plusLIEs lies) + +tcMonoExpr expr@(RecordCon con_name rbinds) res_ty + = tcAddErrCtxt (recordConCtxt expr) $ + tcId con_name `thenNF_Tc` \ (con_expr, con_lie, con_tau) -> let - (_, record_ty) = splitFunTy 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 (maybeAppDataTyCon record_ty ) ) - - tcRecordBinds record_ty rbinds `thenTc` \ (rbinds', rbinds_lie) -> + ASSERT( isAlgTyCon tycon ) + unifyTauTy res_ty record_ty `thenTc_` -- Check that the record bindings match the constructor - tcLookupGlobalValue con `thenNF_Tc` \ con_id -> - checkTc (checkRecordFields rbinds con_id) - (badFieldsCon con rbinds) `thenTc_` - - returnTc (RecordCon con_expr rbinds', con_lie `plusLIE` rbinds_lie, record_ty) - --- One small complication in RecordUpd is that we have to generate some --- dictionaries for the data type context, since we are going to --- do some construction. + -- con_name is syntactically constrained to be a data constructor + tcLookupDataCon con_name `thenTc` \ data_con -> + let + bad_fields = badFields rbinds data_con + in + if 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 + 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: -- --- What dictionaries do we need? For the moment we assume that all --- data constructors have the same context, and grab it from the first --- constructor. If they have varying contexts then we'd have to --- union the ones that could participate in the update. - -tcExpr (RecordUpd record_expr rbinds) - = ASSERT( not (null rbinds) ) - tcAddErrCtxt recordUpdCtxt $ +-- data T a b = MkT1 { fa :: a, fb :: b } +-- | MkT2 { fa :: a, fc :: Int -> Int } +-- | MkT3 { fd :: a } +-- +-- upd :: T a b -> c -> T a c +-- upd t x = t { fb = x} +-- +-- The type signature on upd is correct (i.e. the result should not be (T a b)) +-- because upd should be equivalent to: +-- +-- upd t x = case t of +-- MkT1 p q -> MkT1 p x +-- MkT2 a b -> MkT2 p b +-- MkT3 d -> error ... +-- +-- So we need to give a completely fresh type to the result record, +-- and then constrain it by the fields that are *not* updated ("p" above). +-- +-- Note that because MkT3 doesn't contain all the fields being updated, +-- its RHS is simply an error, so it doesn't impose any type constraints +-- +-- All this is done in STEP 4 below. - tcExpr record_expr `thenTc` \ (record_expr', record_lie, record_ty) -> - tcRecordBinds record_ty rbinds `thenTc` \ (rbinds', rbinds_lie) -> +tcMonoExpr expr@(RecordUpd record_expr rbinds) res_ty + = tcAddErrCtxt (recordUpdCtxt expr) $ - -- Check that the field names are plausible - zonkTcType record_ty `thenNF_Tc` \ record_ty' -> + -- STEP 0 + -- Check that the field names are really field names + ASSERT( not (null rbinds) ) + let + field_names = [field_name | (field_name, _, _) <- rbinds] + in + mapNF_Tc tcLookupGlobal_maybe field_names `thenNF_Tc` \ maybe_sel_ids -> let - (tycon, inst_tys, data_cons) = --trace "TcExpr.getAppDataTyCon" $ - getAppDataTyCon record_ty' - -- The record binds are non-empty (syntax); so at least one field - -- label will have been unified with record_ty by tcRecordBinds; - -- field labels must be of data type; hencd the getAppDataTyCon must succeed. - (tyvars, theta, _, _) = dataConSig (head data_cons) + 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 - tcInstTheta (zipEqual "tcExpr:RecordUpd" tyvars inst_tys) theta `thenNF_Tc` \ theta' -> - newDicts RecordUpdOrigin theta' `thenNF_Tc` \ (con_lie, dicts) -> - checkTc (any (checkRecordFields rbinds) data_cons) - (badFieldsUpd rbinds) `thenTc_` - - returnTc (RecordUpdOut record_expr' dicts rbinds', - con_lie `plusLIE` record_lie `plusLIE` rbinds_lie, - record_ty) - -tcExpr (ArithSeqIn seq@(From expr)) - = tcExpr expr `thenTc` \ (expr', lie1, ty) -> + 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 + -- 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, _) -> - tcLookupGlobalValueByKey enumFromClassOpKey `thenNF_Tc` \ sel_id -> - newMethod (ArithSeqOrigin seq) - (RealId sel_id) [ty] `thenNF_Tc` \ (lie2, enum_from_id) -> + -- STEP 2 + -- Check that at least one constructor has all the named fields + -- i.e. has an empty set of bad fields returned by badFields + checkTc (any (null . badFields rbinds) data_cons) + (badFieldsUpd rbinds) `thenTc_` - returnTc (ArithSeqOut (HsVar enum_from_id) (From expr'), - lie1 `plusLIE` lie2, - mkListTy ty) + -- STEP 3 + -- Typecheck the update bindings. + -- (Do this after checking for bad fields in case there's a field that + -- doesn't match the constructor.) + let + result_record_ty = mkTyConApp tycon result_inst_tys + in + unifyTauTy res_ty result_record_ty `thenTc_` + tcRecordBinds tycon result_inst_tys rbinds `thenTc` \ (rbinds', rbinds_lie) -> + + -- STEP 4 + -- Use the un-updated fields to find a vector of booleans saying + -- which type arguments must be the same in updatee and result. + -- + -- WARNING: this code assumes that all data_cons in a common tycon + -- have FieldLabels abstracted over the same tyvars. + let + upd_field_lbls = [recordSelectorFieldLabel sel_id | (sel_id, _, _) <- rbinds'] + con_field_lbls_s = map dataConFieldLabels data_cons -tcExpr in_expr@(ArithSeqIn seq@(FromThen expr1 expr2)) - = tcExpr expr1 `thenTc` \ (expr1',lie1,ty1) -> - tcExpr expr2 `thenTc` \ (expr2',lie2,ty2) -> + -- A constructor is only relevant to this process if + -- it contains all the fields that are being updated + relevant_field_lbls_s = filter is_relevant con_field_lbls_s + is_relevant con_field_lbls = all (`elem` con_field_lbls) upd_field_lbls - tcAddErrCtxt (arithSeqCtxt in_expr) $ - unifyTauTyList [ty1, ty2] `thenTc_` + non_upd_field_lbls = concat relevant_field_lbls_s `minusList` upd_field_lbls + common_tyvars = tyVarsOfTypes (map fieldLabelType non_upd_field_lbls) - tcLookupGlobalValueByKey enumFromThenClassOpKey `thenNF_Tc` \ sel_id -> - newMethod (ArithSeqOrigin seq) - (RealId sel_id) [ty1] `thenNF_Tc` \ (lie3, enum_from_then_id) -> + mk_inst_ty (tyvar, result_inst_ty) + | tyvar `elemVarSet` common_tyvars = returnNF_Tc result_inst_ty -- Same as result type + | otherwise = newTyVarTy liftedTypeKind -- Fresh type + in + mapNF_Tc mk_inst_ty (zip con_tyvars result_inst_tys) `thenNF_Tc` \ inst_tys -> - returnTc (ArithSeqOut (HsVar enum_from_then_id) - (FromThen expr1' expr2'), - lie1 `plusLIE` lie2 `plusLIE` lie3, - mkListTy ty1) + -- STEP 5 + -- Typecheck the expression to be updated + let + record_ty = mkTyConApp tycon inst_tys + in + tcMonoExpr record_expr record_ty `thenTc` \ (record_expr', record_lie) -> + + -- STEP 6 + -- Figure out the LIE we need. We have to generate some + -- dictionaries for the data type context, since we are going to + -- do some construction. + -- + -- What dictionaries do we need? For the moment we assume that all + -- data constructors have the same context, and grab it from the first + -- constructor. If they have varying contexts then we'd have to + -- union the ones that could participate in the update. + let + (tyvars, theta, _, _, _, _) = dataConSig (head data_cons) + inst_env = mkTopTyVarSubst tyvars result_inst_tys + theta' = substTheta inst_env theta + in + newDicts RecordUpdOrigin theta' `thenNF_Tc` \ dicts -> -tcExpr in_expr@(ArithSeqIn seq@(FromTo expr1 expr2)) - = tcExpr expr1 `thenTc` \ (expr1',lie1,ty1) -> - tcExpr expr2 `thenTc` \ (expr2',lie2,ty2) -> + -- Phew! + returnTc (RecordUpdOut record_expr' record_ty result_record_ty (map instToId dicts) rbinds', + mkLIE dicts `plusLIE` record_lie `plusLIE` rbinds_lie) - tcAddErrCtxt (arithSeqCtxt in_expr) $ - unifyTauTyList [ty1,ty2] `thenTc_` +tcMonoExpr (ArithSeqIn seq@(From expr)) res_ty + = unifyListTy res_ty `thenTc` \ elt_ty -> + tcMonoExpr expr elt_ty `thenTc` \ (expr', lie1) -> - tcLookupGlobalValueByKey enumFromToClassOpKey `thenNF_Tc` \ sel_id -> + tcLookupGlobalId enumFromName `thenNF_Tc` \ sel_id -> newMethod (ArithSeqOrigin seq) - (RealId sel_id) [ty1] `thenNF_Tc` \ (lie3, enum_from_to_id) -> - - returnTc (ArithSeqOut (HsVar enum_from_to_id) + sel_id [elt_ty] `thenNF_Tc` \ enum_from -> + + 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) -> + tcLookupGlobalId enumFromThenName `thenNF_Tc` \ sel_id -> + newMethod (ArithSeqOrigin seq) sel_id [elt_ty] `thenNF_Tc` \ enum_from_then -> + + 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) -> + tcLookupGlobalId enumFromToName `thenNF_Tc` \ sel_id -> + newMethod (ArithSeqOrigin seq) sel_id [elt_ty] `thenNF_Tc` \ enum_from_to -> + + returnTc (ArithSeqOut (HsVar (instToId enum_from_to)) (FromTo expr1' expr2'), - lie1 `plusLIE` lie2 `plusLIE` lie3, - mkListTy ty1) - -tcExpr in_expr@(ArithSeqIn seq@(FromThenTo expr1 expr2 expr3)) - = tcExpr expr1 `thenTc` \ (expr1',lie1,ty1) -> - tcExpr expr2 `thenTc` \ (expr2',lie2,ty2) -> - tcExpr expr3 `thenTc` \ (expr3',lie3,ty3) -> - - tcAddErrCtxt (arithSeqCtxt in_expr) $ - unifyTauTyList [ty1,ty2,ty3] `thenTc_` - - tcLookupGlobalValueByKey enumFromThenToClassOpKey `thenNF_Tc` \ sel_id -> - newMethod (ArithSeqOrigin seq) - (RealId sel_id) [ty1] `thenNF_Tc` \ (lie4, eft_id) -> - - returnTc (ArithSeqOut (HsVar eft_id) - (FromThenTo expr1' expr2' expr3'), - lie1 `plusLIE` lie2 `plusLIE` lie3 `plusLIE` lie4, - mkListTy ty1) + 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) -> + 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} -tcExpr in_expr@(ExprWithTySig expr poly_ty) - = tcExpr expr `thenTc` \ (texpr, lie, tau_ty) -> - tcHsType poly_ty `thenTc` \ sigma_sig -> - - -- Check the tau-type part - tcSetErrCtxt (exprSigCtxt in_expr) $ - tcInstSigType sigma_sig `thenNF_Tc` \ sigma_sig' -> - let - (sig_tyvars', sig_theta', sig_tau') = splitSigmaTy sigma_sig' - in - unifyTauTy sig_tau' tau_ty `thenTc_` - - -- Check the type variables of the signature - checkSigTyVars sig_tyvars' sig_tau' `thenTc_` - - -- Check overloading constraints - newDicts SignatureOrigin sig_theta' `thenNF_Tc` \ (sig_dicts, _) -> - tcSimplifyAndCheck - (mkTyVarSet sig_tyvars') - sig_dicts lie `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, except for any default - -- resolution it may have done, which is recorded in the - -- substitution. - returnTc (texpr, lie, tau_ty) +tcMonoExpr (HsWith expr binds) res_ty + = tcMonoExpr expr res_ty `thenTc` \ (expr', expr_lie) -> + mapAndUnzip3Tc tcIPBind binds `thenTc` \ (avail_ips, binds', bind_lies) -> + + -- 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} %************************************************************************ @@ -497,129 +617,86 @@ tcExpr in_expr@(ExprWithTySig expr poly_ty) %************************************************************************ \begin{code} -tcApp :: RenamedHsExpr -> [RenamedHsExpr] -- Function and args - -> TcM s (TcExpr s, [TcExpr s], -- Translated fun and args - LIE s, - TcType s) -- Type of the application - -tcApp fun args - = -- First type-check the function - -- In the HsVar case we go straight to tcId to avoid hitting the - -- rank-2 check, which we check later here anyway - (case fun of - HsVar name -> tcId name `thenNF_Tc` \ stuff -> returnTc stuff - other -> tcExpr fun - ) `thenTc` \ (fun', lie_fun, fun_ty) -> - - tcApp_help fun 1 fun_ty args `thenTc` \ (args', lie_args, res_ty) -> - -- Check that the result type doesn't have any nested for-alls. - -- For example, a "build" on its own is no good; it must be applied to something. - checkTc (isTauTy res_ty) - (lurkingRank2Err fun fun_ty) `thenTc_` +tcApp :: RenamedHsExpr -> [RenamedHsExpr] -- Function and args + -> TcType -- Expected result type of application + -> TcM (TcExpr, LIE) -- Translated fun and args - returnTc (fun', args', lie_fun `plusLIE` lie_args, res_ty) +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 + tcExpr_id fun `thenTc` \ (fun', lie_fun, fun_ty) -> + + tcAddErrCtxt (wrongArgsCtxt "too many" fun args) ( + split_fun_ty fun_ty (length args) + ) `thenTc` \ (expected_arg_tys, actual_result_ty) -> + + -- Now typecheck the args + mapAndUnzipTc (tcArg fun) + (zip3 args expected_arg_tys [1..]) `thenTc` \ (args', lie_args_s) -> + + -- Unify with expected result after type-checking the args + -- so that the info from args percolates to actual_result_ty. + -- This is when we might detect a too-few args situation. + -- (One can think of cases when the opposite order would give + -- a better error message.) + tcAddErrCtxtM (checkArgsCtxt fun args res_ty actual_result_ty) + (tcSub res_ty actual_result_ty) `thenTc` \ (co_fn, lie_res) -> + + returnTc (co_fn <$> foldl HsApp fun' args', + lie_res `plusLIE` lie_fun `plusLIE` plusLIEs lie_args_s) + + +-- If an error happens we try to figure out whether the +-- function has been given too many or too few arguments, +-- and say so +checkArgsCtxt fun args expected_res_ty actual_res_ty tidy_env + = zonkTcType expected_res_ty `thenNF_Tc` \ exp_ty' -> + zonkTcType actual_res_ty `thenNF_Tc` \ act_ty' -> + let + (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'' -tcApp_help :: RenamedHsExpr -> Int -- Function and arg position, used in error message(s) - -> TcType s -- The type of the function - -> [RenamedHsExpr] -- Arguments - -> TcM s ([TcExpr s], -- Typechecked args - LIE s, - TcType s) -- Result type of the application - -tcApp_help orig_fun arg_no fun_ty [] - = returnTc ([], emptyLIE, fun_ty) + len_act_args = length act_args + len_exp_args = length exp_args -tcApp_help orig_fun arg_no fun_ty all_args@(arg:args) - = -- Expect the function to have type A->B - tcAddErrCtxt (tooManyArgsCtxt orig_fun) ( - unifyFunTy fun_ty - ) `thenTc` \ (expected_arg_ty, result_ty) -> + 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) - -- Type check the argument - tcAddErrCtxt (funAppCtxt orig_fun arg_no arg) ( - tcArg expected_arg_ty arg - ) `thenTc` \ (arg', lie_arg) -> - -- Do the other args - tcApp_help orig_fun (arg_no+1) result_ty args `thenTc` \ (args', lie_args, res_ty) -> +split_fun_ty :: TcType -- The type of the function + -> Int -- Number of arguments + -> TcM ([TcType], -- Function argument types + TcType) -- Function result types - -- Done - returnTc (arg':args', lie_arg `plusLIE` lie_args, res_ty) +split_fun_ty fun_ty 0 + = returnTc ([], fun_ty) +split_fun_ty fun_ty n + = -- Expect the function to have type A->B + unifyFunTy fun_ty `thenTc` \ (arg_ty, res_ty) -> + split_fun_ty res_ty (n-1) `thenTc` \ (arg_tys, final_res_ty) -> + returnTc (arg_ty:arg_tys, final_res_ty) \end{code} \begin{code} -tcArg :: TcType s -- Expected arg type - -> RenamedHsExpr -- Actual argument - -> TcM s (TcExpr s, LIE s) -- Resulting argument and LIE - -tcArg expected_arg_ty arg - | not (maybeToBool (getForAllTy_maybe expected_arg_ty)) - = -- The ordinary, non-rank-2 polymorphic case - tcExpr arg `thenTc` \ (arg', lie_arg, actual_arg_ty) -> - unifyTauTy expected_arg_ty actual_arg_ty `thenTc_` - returnTc (arg', lie_arg) +tcArg :: RenamedHsExpr -- The function (for error messages) + -> (RenamedHsExpr, TcSigmaType, Int) -- Actual argument and expected arg type + -> TcM (TcExpr, LIE) -- Resulting argument and LIE - | otherwise - = -- Ha! The argument type of the function is a for-all type, - -- An example of rank-2 polymorphism. - - -- No need to instantiate the argument type... it's must be the result - -- of instantiating a function involving rank-2 polymorphism, so there - -- isn't any danger of using the same tyvars twice - -- The argument type shouldn't be overloaded type (hence ASSERT) - - -- To ensure that the forall'd type variables don't get unified with each - -- other or any other types, we make fresh *signature* type variables - -- and unify them with the tyvars. - tcInstSigTcType expected_arg_ty `thenNF_Tc` \ (sig_tyvars, sig_rho) -> - let - (sig_theta, sig_tau) = splitRhoTy sig_rho - in - ASSERT( null sig_theta ) -- And expected_tyvars are all DontBind things - - -- Type-check the arg and unify with expected type - tcExpr arg `thenTc` \ (arg', lie_arg, actual_arg_ty) -> - unifyTauTy sig_tau actual_arg_ty `thenTc_` - - -- 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. - - tcAddErrCtxt (rank2ArgCtxt arg expected_arg_ty) ( - tcExtendGlobalTyVars (tyVarsOfType expected_arg_ty) ( - checkSigTyVars sig_tyvars sig_tau - ) `thenTc_` - - -- Check that there's no overloading involved - -- Even if there isn't, there may be some Insts which mention the expected_tyvars, - -- but which, on simplification, don't actually need a dictionary involving - -- the tyvar. So we have to do a proper simplification right here. - tcSimplifyRank2 (mkTyVarSet sig_tyvars) - lie_arg `thenTc` \ (free_insts, inst_binds) -> - - -- 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. - returnTc (TyLam sig_tyvars (HsLet (mk_binds inst_binds) arg'), free_insts) - ) - where - - mk_binds [] = EmptyBinds - mk_binds ((inst,rhs):inst_binds) - = (SingleBind (NonRecBind (VarMonoBind inst rhs))) `ThenBinds` - mk_binds inst_binds +tcArg the_fun (arg, expected_arg_ty, arg_no) + = tcAddErrCtxt (funAppCtxt the_fun arg arg_no) $ + tcExpr arg expected_arg_ty \end{code} + %************************************************************************ %* * \subsection{@tcId@ typchecks an identifier occurrence} @@ -627,105 +704,20 @@ tcArg expected_arg_ty arg %************************************************************************ \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) - - Nothing -> tcLookupGlobalValue name `thenNF_Tc` \ id -> - tcInstType [] (idType id) `thenNF_Tc` \ inst_ty -> - let - (tyvars, rho) = splitForAllTy inst_ty - in - instantiate_it2 (RealId id) tyvars rho - - where - -- The instantiate_it loop runs round instantiating the Id. - -- It has to be a loop because we are now prepared to entertain - -- types like - -- f:: forall a. Eq a => forall b. Baz b => tau - -- We want to instantiate this to - -- f2::tau {f2 = f1 b (Baz b), f1 = f a (Eq a)} - instantiate_it tc_id_occ ty - = tcInstTcType ty `thenNF_Tc` \ (tyvars, rho) -> - instantiate_it2 tc_id_occ tyvars rho - - instantiate_it2 tc_id_occ tyvars rho - | null theta -- Is it overloaded? - = returnNF_Tc (mkHsTyApp (HsVar tc_id_occ) arg_tys, emptyLIE, tau) - - | otherwise -- Yes, it's overloaded - = newMethodWithGivenTy (OccurrenceOf tc_id_occ) - tc_id_occ arg_tys rho `thenNF_Tc` \ (lie1, meth_id) -> - instantiate_it meth_id tau `thenNF_Tc` \ (expr, lie2, final_tau) -> - returnNF_Tc (expr, lie1 `plusLIE` lie2, final_tau) - - where - (theta, tau) = splitRhoTy rho - arg_tys = mkTyVarTys tyvars +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} -%************************************************************************ -%* * -\subsection{@tcQuals@ typechecks list-comprehension qualifiers} -%* * -%************************************************************************ +Typecheck expression which in most cases will be an Id. \begin{code} -tcListComp expr [] - = tcExpr expr `thenTc` \ (expr', lie, ty) -> - returnTc ((expr',[]), lie, mkListTy ty) - -tcListComp expr (qual@(FilterQual filter) : quals) - = tcAddErrCtxt (qualCtxt qual) ( - tcExpr filter `thenTc` \ (filter', filter_lie, filter_ty) -> - unifyTauTy boolTy filter_ty `thenTc_` - returnTc (FilterQual filter', filter_lie) - ) `thenTc` \ (qual', qual_lie) -> - - tcListComp expr quals `thenTc` \ ((expr',quals'), rest_lie, res_ty) -> - - returnTc ((expr', qual' : quals'), - qual_lie `plusLIE` rest_lie, - res_ty) - -tcListComp expr (qual@(GeneratorQual pat rhs) : quals) - = newMonoIds binder_names mkBoxedTypeKind (\ ids -> - - tcAddErrCtxt (qualCtxt qual) ( - tcPat pat `thenTc` \ (pat', lie_pat, pat_ty) -> - tcExpr rhs `thenTc` \ (rhs', lie_rhs, rhs_ty) -> - -- NB: the environment has been extended with the new binders - -- which the rhs can't "see", but the renamer should have made - -- sure that everything is distinct by now, so there's no problem. - -- Putting the tcExpr before the newMonoIds messes up the nesting - -- of error contexts, so I didn't bother - - unifyTauTy (mkListTy pat_ty) rhs_ty `thenTc_` - returnTc (GeneratorQual pat' rhs', - lie_pat `plusLIE` lie_rhs) - ) `thenTc` \ (qual', lie_qual) -> - - tcListComp expr quals `thenTc` \ ((expr',quals'), lie_rest, res_ty) -> - - returnTc ((expr', qual' : quals'), - lie_qual `plusLIE` lie_rest, - res_ty) - ) - where - binder_names = collectPatBinders pat - -tcListComp expr (LetQual binds : quals) - = tcBindsAndThen -- No error context, but a binding group is - combine -- rather a large thing for an error context anyway - binds - (tcListComp expr quals) - where - combine binds' (expr',quals') = (expr', LetQual binds' : quals') +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} @@ -736,235 +728,284 @@ tcListComp expr (LetQual binds : quals) %************************************************************************ \begin{code} -tcDoStmts stmts src_loc +-- 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 mkBoxedTypeKind mkBoxedTypeKind) `thenNF_Tc` \ m -> + -- 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)) - -- Build the then and zero methods in case we need them - tcLookupGlobalValueByKey thenMClassOpKey `thenNF_Tc` \ then_sel_id -> - tcLookupGlobalValueByKey zeroClassOpKey `thenNF_Tc` \ zero_sel_id -> - newMethod DoOrigin - (RealId then_sel_id) [m] `thenNF_Tc` \ (m_lie, then_id) -> - newMethod DoOrigin - (RealId zero_sel_id) [m] `thenNF_Tc` \ (mz_lie, zero_id) -> + 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 (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, + -- not only for typechecker efficiency, but also because otherwise during + -- simplification we end up with silly stuff like + -- then = case d of (t,r) -> t + -- then = then + -- where the second "then" sees that it already exists in the "available" stuff. + -- + 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 - get_m_arg ty - = newTyVarTy mkTypeKind `thenNF_Tc` \ arg_ty -> - unifyTauTy (mkAppTy m arg_ty) ty `thenTc_` - returnTc arg_ty - - go [stmt@(ExprStmt exp src_loc)] - = tcAddSrcLoc src_loc $ - tcSetErrCtxt (stmtCtxt stmt) $ - tcExpr exp `thenTc` \ (exp', exp_lie, exp_ty) -> - returnTc ([ExprStmt exp' src_loc], exp_lie, exp_ty) - - go (stmt@(ExprStmt exp src_loc) : stmts) - = tcAddSrcLoc src_loc ( - tcSetErrCtxt (stmtCtxt stmt) ( - tcExpr exp `thenTc` \ (exp', exp_lie, exp_ty) -> - get_m_arg exp_ty `thenTc` \ a -> - returnTc (a, exp', exp_lie) - )) `thenTc` \ (a, exp', exp_lie) -> - go stmts `thenTc` \ (stmts', stmts_lie, stmts_ty) -> - get_m_arg stmts_ty `thenTc` \ b -> - returnTc (ExprStmtOut exp' src_loc a b : stmts', - exp_lie `plusLIE` stmts_lie `plusLIE` m_lie, - stmts_ty) - - go (stmt@(BindStmt pat exp src_loc) : stmts) - = newMonoIds (collectPatBinders pat) mkBoxedTypeKind $ \ _ -> - tcAddSrcLoc src_loc ( - tcSetErrCtxt (stmtCtxt stmt) ( - tcPat pat `thenTc` \ (pat', pat_lie, pat_ty) -> - tcExpr exp `thenTc` \ (exp', exp_lie, exp_ty) -> - -- See comments with tcListComp on GeneratorQual - - get_m_arg exp_ty `thenTc` \ a -> - unifyTauTy pat_ty a `thenTc_` - returnTc (a, pat', exp', pat_lie `plusLIE` exp_lie) - )) `thenTc` \ (a, pat', exp', stmt_lie) -> - go stmts `thenTc` \ (stmts', stmts_lie, stmts_ty) -> - get_m_arg stmts_ty `thenTc` \ b -> - returnTc (BindStmtOut pat' exp' src_loc a b : stmts', - stmt_lie `plusLIE` stmts_lie `plusLIE` m_lie `plusLIE` - (if failureFreePat pat' then emptyLIE else mz_lie), - stmts_ty) - - go (LetStmt binds : stmts) - = tcBindsAndThen -- No error context, but a binding group is - combine -- rather a large thing for an error context anyway - binds - (go stmts) - where - combine binds' stmts' = LetStmt binds' : stmts' + monad_lie = mkLIE [return_inst, then_inst, fail_inst] in - - go stmts `thenTc` \ (stmts', final_lie, final_ty) -> - returnTc (HsDoOut stmts' then_id zero_id src_loc, - final_lie, - final_ty) + 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} + +%************************************************************************ +%* * +\subsection{Record bindings} +%* * +%************************************************************************ + 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 -> - tcInstId sel_id `thenNF_Tc` \ (_, _, tau) -> + tenv = mkTopTyVarSubst (tyConTyVars tycon) ty_args - -- Record selectors all have type - -- forall a1..an. T a1 .. an -> tau - ASSERT( maybeToBool (getFunTy_maybe tau) ) + do_bind (field_lbl_name, rhs, pun_flag) + = tcLookupGlobalId field_lbl_name `thenNF_Tc` \ sel_id -> let - -- Selector must have type RecordType -> FieldType - Just (record_ty, field_ty) = getFunTy_maybe tau + field_lbl = recordSelectorFieldLabel sel_id + field_ty = substTy tenv (fieldLabelType field_lbl) in - unifyTauTy expected_record_ty record_ty `thenTc_` - tcArg field_ty rhs `thenTc` \ (rhs', lie) -> - returnTc ((RealId sel_id, rhs', pun_flag), lie) - -checkRecordFields :: RenamedRecordBinds -> Id -> Bool -- True iff all the fields in - -- RecordBinds are field of the - -- specified constructor -checkRecordFields rbinds data_con - = all ok rbinds - where - data_con_fields = dataConFieldLabels data_con - - ok (field_name, _, _) = any (match (getName field_name)) data_con_fields + ASSERT( isRecordSelector sel_id ) + -- This lookup and assertion will surely succeed, because + -- we check that the fields are indeed record selectors + -- before calling tcRecordBinds + ASSERT2( fieldLabelTyCon field_lbl == tycon, ppr field_lbl ) + -- The caller of tcRecordBinds has already checked + -- that all the fields come from the same type + + tcExpr rhs field_ty `thenTc` \ (rhs', lie) -> + + returnTc ((sel_id, rhs', pun_flag), lie) + +badFields rbinds data_con + = [field_name | (field_name, _, _) <- rbinds, + not (field_name `elem` field_names) + ] + where + field_names = map fieldLabelName (dataConFieldLabels data_con) - match field_name field_label = field_name == fieldLabelName field_label +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} %************************************************************************ %* * -\subsection{@tcExprs@ typechecks a {\em list} of expressions} +\subsection{@tcMonoExprs@ typechecks a {\em list} of expressions} %* * %************************************************************************ \begin{code} -tcExprs :: [RenamedHsExpr] -> TcM s ([TcExpr s], LIE s, [TcType s]) +tcMonoExprs :: [RenamedHsExpr] -> [TcType] -> TcM ([TcExpr], LIE) -tcExprs [] = returnTc ([], emptyLIE, []) -tcExprs (expr:exprs) - = tcExpr expr `thenTc` \ (expr', lie1, ty) -> - tcExprs exprs `thenTc` \ (exprs', lie2, tys) -> - returnTc (expr':exprs', lie1 `plusLIE` lie2, ty:tys) +tcMonoExprs [] [] = returnTc ([], emptyLIE) +tcMonoExprs (expr:exprs) (ty:tys) + = tcMonoExpr expr ty `thenTc` \ (expr', lie1) -> + tcMonoExprs exprs tys `thenTc` \ (exprs', lie2) -> + returnTc (expr':exprs', lie1 `plusLIE` lie2) \end{code} -% ================================================= +%************************************************************************ +%* * +\subsection{Literals} +%* * +%************************************************************************ -Errors and contexts -~~~~~~~~~~~~~~~~~~~ +Overloaded literals. -Mini-utils: \begin{code} -pp_nest_hang :: String -> Pretty -> Pretty -pp_nest_hang label stuff = ppNest 2 (ppHang (ppStr 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} -Boring and alphabetical: -\begin{code} -arithSeqCtxt expr sty - = ppHang (ppStr "In an arithmetic sequence:") 4 (ppr sty expr) -branchCtxt b1 b2 sty - = ppSep [ppStr "In the branches of a conditional:", - pp_nest_hang "`then' branch:" (ppr sty b1), - pp_nest_hang "`else' branch:" (ppr sty b2)] +%************************************************************************ +%* * +\subsection{Errors and contexts} +%* * +%************************************************************************ -caseCtxt expr sty - = ppHang (ppStr "In a case expression:") 4 (ppr sty expr) +Mini-utils: -exprSigCtxt expr sty - = ppHang (ppStr "In an expression with a type signature:") - 4 (ppr sty expr) +Boring and alphabetical: +\begin{code} +arithSeqCtxt expr + = hang (ptext SLIT("In an arithmetic sequence:")) 4 (ppr expr) -listCtxt expr sty - = ppHang (ppStr "In a list expression:") 4 (ppr sty expr) +parrSeqCtxt expr + = hang (ptext SLIT("In a parallel array sequence:")) 4 (ppr expr) -predCtxt expr sty - = ppHang (ppStr "In a predicate expression:") 4 (ppr sty expr) +caseCtxt expr + = hang (ptext SLIT("In the case expression:")) 4 (ppr expr) -sectionRAppCtxt expr sty - = ppHang (ppStr "In a right section:") 4 (ppr sty expr) +caseScrutCtxt expr + = hang (ptext SLIT("In the scrutinee of a case expression:")) 4 (ppr expr) -sectionLAppCtxt expr sty - = ppHang (ppStr "In a left section:") 4 (ppr sty expr) +exprSigCtxt expr + = hang (ptext SLIT("In an expression with a type signature:")) + 4 (ppr expr) -funAppCtxt fun arg_no arg sty - = ppHang (ppCat [ ppStr "In the", speakNth arg_no, ppStr "argument of", - ppr sty fun `ppBeside` ppStr ", namely"]) - 4 (pprParendExpr sty arg) +listCtxt expr + = hang (ptext SLIT("In the list element:")) 4 (ppr expr) -qualCtxt qual sty - = ppHang (ppStr "In a list-comprehension qualifer:") - 4 (ppr sty qual) +parrCtxt expr + = hang (ptext SLIT("In the parallel array element:")) 4 (ppr expr) -stmtCtxt stmt sty - = ppHang (ppStr "In a do statement:") - 4 (ppr sty stmt) +predCtxt expr + = hang (ptext SLIT("In the predicate expression:")) 4 (ppr expr) -tooManyArgsCtxt f sty - = ppHang (ppStr "Too many arguments in an application of the function") - 4 (ppr sty f) +exprCtxt expr + = hang (ptext SLIT("In the expression:")) 4 (ppr expr) -lurkingRank2Err fun fun_ty sty - = ppHang (ppCat [ppStr "Illegal use of", ppr sty fun]) - 4 (ppAboves [ppStr "It is applied to too few arguments,", - ppStr "so that the result type has for-alls in it"]) +funAppCtxt fun arg arg_no + = hang (hsep [ ptext SLIT("In the"), speakNth arg_no, ptext SLIT("argument of"), + quotes (ppr fun) <> text ", namely"]) + 4 (quotes (ppr arg)) -rank2ArgCtxt arg expected_arg_ty sty - = ppHang (ppStr "In a polymorphic function argument:") - 4 (ppSep [ppBeside (ppr sty arg) (ppStr " ::"), - ppr sty expected_arg_ty]) +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 -badFieldsUpd rbinds sty - = ppHang (ppStr "No constructor has all these fields:") - 4 (interpp'SP sty fields) +appCtxt fun args + = ptext SLIT("In the application") <+> quotes (ppr the_app) where - fields = [field | (field, _, _) <- rbinds] + the_app = foldl HsApp fun args -- Used in error messages -recordUpdCtxt sty = ppStr "In a record update construct" +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]) -badFieldsCon con rbinds sty - = ppHang (ppBesides [ppStr "Inconsistent constructor:", ppr sty con]) - 4 (ppBesides [ppStr "and fields:", interpp'SP sty fields]) +badFieldsUpd rbinds + = hang (ptext SLIT("No constructor has all these fields:")) + 4 (pprQuotedList fields) where fields = [field | (field, _, _) <- rbinds] + +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}