X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Fcompiler%2Ftypecheck%2FTcExpr.lhs;h=7aecdaaf81061d0ed2b46ca7a47a652039bbfbd0;hb=3ca33229d4b9c1ed2829318631e73e748154f3ff;hp=809e08f9ff0fa8fafcdcf19af89658994f00c7ea;hpb=7b0181919416d8f04324575b7e17031ca692f5b0;p=ghc-hetmet.git diff --git a/ghc/compiler/typecheck/TcExpr.lhs b/ghc/compiler/typecheck/TcExpr.lhs index 809e08f..7aecdaa 100644 --- a/ghc/compiler/typecheck/TcExpr.lhs +++ b/ghc/compiler/typecheck/TcExpr.lhs @@ -1,79 +1,177 @@ % -% (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 ) where +module TcExpr ( tcApp, tcExpr, tcPolyExpr, tcId ) where -import Ubiq +#include "HsVersions.h" -import HsSyn ( HsExpr(..), Qual(..), Stmt(..), - HsBinds(..), Bind(..), MonoBinds(..), - ArithSeqInfo(..), HsLit(..), Sig, GRHSsAndBinds, - Match, Fake, InPat, OutPat, PolyType, - irrefutablePat, collectPatBinders ) -import RnHsSyn ( RenamedHsExpr(..), RenamedQual(..), - RenamedStmt(..), RenamedRecordBinds(..), - RnName{-instance Outputable-} +import HsSyn ( HsExpr(..), HsLit(..), ArithSeqInfo(..), + HsBinds(..), Stmt(..), StmtCtxt(..), + mkMonoBind, nullMonoBinds ) -import TcHsSyn ( TcExpr(..), TcQual(..), TcStmt(..), - TcIdOcc(..), TcRecordBinds(..), - mkHsTyApp +import RnHsSyn ( RenamedHsExpr, RenamedRecordBinds ) +import TcHsSyn ( TcExpr, TcRecordBinds, + mkHsTyApp, mkHsLet, maybeBoxedPrimType ) import TcMonad +import BasicTypes ( RecFlag(..) ) + import Inst ( Inst, InstOrigin(..), OverloadedLit(..), - LIE(..), emptyLIE, plusLIE, plusLIEs, newOverloadedLit, - newMethod, newMethodWithGivenTy, newDicts ) + LIE, emptyLIE, unitLIE, consLIE, plusLIE, plusLIEs, + lieToList, listToLIE, tyVarsOfLIE, zonkLIE, + newOverloadedLit, newMethod, newIPDict, + instOverloadedFun, newDicts, newClassDicts, + partitionLIEbyMeth, getIPsOfLIE, instToId, ipToId + ) import TcBinds ( tcBindsAndThen ) -import TcEnv ( tcLookupLocalValue, tcLookupGlobalValue, tcLookupClassByKey, - tcLookupGlobalValueByKey, newMonoIds, tcGetGlobalTyVars +import TcEnv ( tcInstId, + tcLookupValue, tcLookupClassByKey, + tcLookupValueByKey, + tcExtendGlobalTyVars, tcLookupValueMaybe, + tcLookupTyCon, tcLookupDataCon + ) +import TcMatches ( tcMatchesCase, tcMatchLambda, tcStmts ) +import TcMonoType ( tcHsType, checkSigTyVars, sigCtxt ) +import TcPat ( badFieldCon ) +import TcSimplify ( tcSimplify, tcSimplifyAndCheck ) +import TcType ( TcType, TcTauType, + tcInstTyVars, + tcInstTcType, tcSplitRhoTy, + newTyVarTy, newTyVarTy_OpenKind, zonkTcType ) + +import Class ( Class ) +import FieldLabel ( FieldLabel, fieldLabelName, fieldLabelType + ) +import Id ( idType, recordSelectorFieldLabel, + isRecordSelector, + Id, mkVanillaId ) -import TcMatches ( tcMatchesCase, tcMatch ) -import TcMonoType ( tcPolyType ) -import TcPat ( tcPat ) -import TcSimplify ( tcSimplifyAndCheck, tcSimplifyRank2 ) -import TcType ( TcType(..), TcMaybe(..), - tcInstId, tcInstType, tcInstTheta, tcInstTcType, tcInstTyVars, - newTyVarTy, zonkTcTyVars, zonkTcType ) -import TcKind ( TcKind ) - -import Class ( Class(..), getClassSig ) -import FieldLabel ( fieldLabelName ) -import Id ( Id(..), GenId, idType, dataConFieldLabels, dataConSig ) -import Kind ( Kind, mkBoxedTypeKind, mkTypeKind, mkArrowKind ) -import GenSpecEtc ( checkSigTyVars, checkSigTyVarsGivenGlobals ) -import Name ( Name{-instance Eq-} ) -import PrelInfo ( intPrimTy, charPrimTy, doublePrimTy, - floatPrimTy, addrPrimTy, addrTy, - boolTy, charTy, stringTy, mkListTy, - mkTupleTy, mkPrimIoTy ) +import DataCon ( dataConFieldLabels, dataConSig, dataConId, + dataConStrictMarks, StrictnessMark(..) + ) +import Name ( Name, getName ) import Type ( mkFunTy, mkAppTy, mkTyVarTy, mkTyVarTys, - getTyVar_maybe, getFunTy_maybe, - splitForAllTy, splitRhoTy, splitSigmaTy, splitFunTy, - isTauTy, mkFunTys, tyVarsOfType, getForAllTy_maybe, - getAppDataTyCon, maybeAppDataTyCon + ipName_maybe, + splitFunTy_maybe, splitFunTys, isNotUsgTy, + mkTyConApp, + splitForAllTys, splitRhoTy, + isTauTy, tyVarsOfType, tyVarsOfTypes, + isForAllTy, splitAlgTyConApp, splitAlgTyConApp_maybe, + boxedTypeKind, mkArrowKind, + tidyOpenType + ) +import Subst ( mkTopTyVarSubst, substClasses ) +import UsageSPUtils ( unannotTy ) +import VarSet ( emptyVarSet, unionVarSet, elemVarSet, mkVarSet ) +import TyCon ( tyConDataCons ) +import TysPrim ( intPrimTy, charPrimTy, doublePrimTy, + floatPrimTy, addrPrimTy ) -import TyVar ( GenTyVar, TyVarSet(..), unionTyVarSets, mkTyVarSet ) -import Unify ( unifyTauTy, unifyTauTyList, unifyTauTyLists, unifyFunTy ) -import Unique ( Unique, cCallableClassKey, cReturnableClassKey, +import TysWiredIn ( boolTy, charTy, stringTy ) +import PrelInfo ( ioTyCon_NAME ) +import TcUnify ( unifyTauTy, unifyFunTy, unifyListTy, unifyTupleTy, + unifyUnboxedTupleTy ) +import Unique ( cCallableClassKey, cReturnableClassKey, enumFromClassOpKey, enumFromThenClassOpKey, enumFromToClassOpKey, enumFromThenToClassOpKey, - monadClassKey, monadZeroClassKey ) - ---import Name ( Name ) -- Instance -import Outputable ( interpp'SP ) -import PprType ( GenType, GenTyVar ) -- Instances -import Maybes ( maybeToBool ) -import Pretty + thenMClassOpKey, failMClassOpKey, returnMClassOpKey + ) +import Outputable +import Maybes ( maybeToBool, mapMaybe ) +import ListSetOps ( minusList ) import Util +import CmdLineOpts ( opt_WarnMissingFields ) + \end{code} +%************************************************************************ +%* * +\subsection{Main wrappers} +%* * +%************************************************************************ + +\begin{code} +tcExpr :: RenamedHsExpr -- Expession to type check + -> TcType -- Expected type (could be a polytpye) + -> TcM s (TcExpr, LIE) + +tcExpr expr ty | isForAllTy ty = -- Polymorphic case + tcPolyExpr expr ty `thenTc` \ (expr', lie, _, _, _) -> + returnTc (expr', lie) + + | otherwise = -- Monomorphic case + tcMonoExpr expr ty +\end{code} + + +%************************************************************************ +%* * +\subsection{@tcPolyExpr@ typchecks an application} +%* * +%************************************************************************ + \begin{code} -tcExpr :: RenamedHsExpr -> TcM s (TcExpr s, LIE s, TcType s) +-- tcPolyExpr is like tcMonoExpr, except that the expected type +-- can be a polymorphic one. +tcPolyExpr :: RenamedHsExpr + -> TcType -- Expected type + -> TcM s (TcExpr, LIE, -- Generalised expr with expected type, and LIE + TcExpr, TcTauType, LIE) -- Same thing, but instantiated; tau-type returned + +tcPolyExpr arg expected_arg_ty + = -- Ha! The argument type of the function is a for-all type, + -- An example of rank-2 polymorphism. + + -- To ensure that the forall'd type variables don't get unified with each + -- other or any other types, we make fresh copy of the alleged type + tcInstTcType expected_arg_ty `thenNF_Tc` \ (sig_tyvars, sig_rho) -> + let + (sig_theta, sig_tau) = splitRhoTy sig_rho + in + -- Type-check the arg and unify with expected type + tcMonoExpr arg sig_tau `thenTc` \ (arg', lie_arg) -> + + -- Check that the sig_tyvars havn't been constrained + -- The interesting bit here is that we must include the free variables + -- of the expected arg ty. Here's an example: + -- runST (newVar True) + -- Here, if we don't make a check, we'll get a type (ST s (MutVar s Bool)) + -- for (newVar True), with s fresh. Then we unify with the runST's arg type + -- forall s'. ST s' a. That unifies s' with s, and a with MutVar s Bool. + -- So now s' isn't unconstrained because it's linked to a. + -- Conclusion: include the free vars of the expected arg type in the + -- list of "free vars" for the signature check. + + tcExtendGlobalTyVars (tyVarsOfType expected_arg_ty) $ + tcAddErrCtxtM (sigCtxt sig_msg expected_arg_ty) $ + + checkSigTyVars sig_tyvars `thenTc` \ zonked_sig_tyvars -> + + newDicts SignatureOrigin sig_theta `thenNF_Tc` \ (sig_dicts, dict_ids) -> + -- ToDo: better origin + tcSimplifyAndCheck + (text "the type signature of an expression") + (mkVarSet zonked_sig_tyvars) + sig_dicts lie_arg `thenTc` \ (free_insts, inst_binds) -> + + let + -- This HsLet binds any Insts which came out of the simplification. + -- It's a bit out of place here, but using AbsBind involves inventing + -- a couple of new names which seems worse. + generalised_arg = TyLam zonked_sig_tyvars $ + DictLam dict_ids $ + mkHsLet inst_binds $ + arg' + in + returnTc ( generalised_arg, free_insts, + arg', sig_tau, lie_arg ) + where + sig_msg ty = sep [ptext SLIT("In an expression with expected type:"), + nest 4 (ppr ty)] \end{code} %************************************************************************ @@ -83,16 +181,30 @@ tcExpr :: RenamedHsExpr -> TcM s (TcExpr s, LIE s, TcType s) %************************************************************************ \begin{code} -tcExpr (HsVar name) - = tcId name `thenNF_Tc` \ (expr', lie, res_ty) -> +tcMonoExpr :: RenamedHsExpr -- Expession to type check + -> TcTauType -- Expected type (could be a type variable) + -> TcM s (TcExpr, LIE) + +tcMonoExpr (HsVar name) res_ty + = tcId name `thenNF_Tc` \ (expr', lie, id_ty) -> + unifyTauTy res_ty id_ty `thenTc_` -- Check that the result type doesn't have any nested for-alls. -- For example, a "build" on its own is no good; it must be -- applied to something. - checkTc (isTauTy res_ty) - (lurkingRank2Err name res_ty) `thenTc_` + checkTc (isTauTy id_ty) + (lurkingRank2Err name id_ty) `thenTc_` - returnTc (expr', lie, res_ty) + returnTc (expr', lie) +\end{code} + +\begin{code} +tcMonoExpr (HsIPVar name) res_ty + -- ZZ What's the `id' used for here... + = let id = mkVanillaId name res_ty in + tcGetInstLoc (OccurrenceOf id) `thenNF_Tc` \ loc -> + newIPDict name res_ty loc `thenNF_Tc` \ ip -> + returnNF_Tc (HsIPVar (instToId ip), unitLIE ip) \end{code} %************************************************************************ @@ -104,59 +216,60 @@ tcExpr (HsVar name) Overloaded literals. \begin{code} -tcExpr (HsLit (HsInt i)) - = newTyVarTy mkBoxedTypeKind `thenNF_Tc` \ ty -> - - newOverloadedLit (LiteralOrigin (HsInt i)) +tcMonoExpr (HsLit (HsInt i)) res_ty + = newOverloadedLit (LiteralOrigin (HsInt i)) (OverloadedIntegral i) - ty `thenNF_Tc` \ (lie, over_lit_id) -> - - returnTc (HsVar over_lit_id, lie, ty) + res_ty `thenNF_Tc` \ stuff -> + returnTc stuff -tcExpr (HsLit (HsFrac f)) - = newTyVarTy mkBoxedTypeKind `thenNF_Tc` \ ty -> - - newOverloadedLit (LiteralOrigin (HsFrac f)) +tcMonoExpr (HsLit (HsFrac f)) res_ty + = newOverloadedLit (LiteralOrigin (HsFrac f)) (OverloadedFractional f) - ty `thenNF_Tc` \ (lie, over_lit_id) -> + res_ty `thenNF_Tc` \ stuff -> + returnTc stuff - returnTc (HsVar over_lit_id, lie, ty) -tcExpr (HsLit lit@(HsLitLit s)) +tcMonoExpr (HsLit lit@(HsLitLit s)) res_ty = 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) + newClassDicts (LitLitOrigin (_UNPK_ s)) + [(cCallableClass,[res_ty])] `thenNF_Tc` \ (dicts, _) -> + returnTc (HsLitOut lit res_ty, dicts) \end{code} Primitive literals: \begin{code} -tcExpr (HsLit lit@(HsCharPrim c)) - = returnTc (HsLitOut lit charPrimTy, emptyLIE, charPrimTy) +tcMonoExpr (HsLit lit@(HsCharPrim c)) res_ty + = unifyTauTy res_ty charPrimTy `thenTc_` + returnTc (HsLitOut lit charPrimTy, emptyLIE) -tcExpr (HsLit lit@(HsStringPrim s)) - = returnTc (HsLitOut lit addrPrimTy, emptyLIE, addrPrimTy) +tcMonoExpr (HsLit lit@(HsStringPrim s)) res_ty + = unifyTauTy res_ty addrPrimTy `thenTc_` + returnTc (HsLitOut lit addrPrimTy, emptyLIE) -tcExpr (HsLit lit@(HsIntPrim i)) - = returnTc (HsLitOut lit intPrimTy, emptyLIE, intPrimTy) +tcMonoExpr (HsLit lit@(HsIntPrim i)) res_ty + = unifyTauTy res_ty intPrimTy `thenTc_` + returnTc (HsLitOut lit intPrimTy, emptyLIE) -tcExpr (HsLit lit@(HsFloatPrim f)) - = returnTc (HsLitOut lit floatPrimTy, emptyLIE, floatPrimTy) +tcMonoExpr (HsLit lit@(HsFloatPrim f)) res_ty + = unifyTauTy res_ty floatPrimTy `thenTc_` + returnTc (HsLitOut lit floatPrimTy, emptyLIE) -tcExpr (HsLit lit@(HsDoublePrim d)) - = returnTc (HsLitOut lit doublePrimTy, emptyLIE, doublePrimTy) +tcMonoExpr (HsLit lit@(HsDoublePrim d)) res_ty + = unifyTauTy res_ty doublePrimTy `thenTc_` + returnTc (HsLitOut lit doublePrimTy, emptyLIE) \end{code} Unoverloaded literals: \begin{code} -tcExpr (HsLit lit@(HsChar c)) - = returnTc (HsLitOut lit charTy, emptyLIE, charTy) +tcMonoExpr (HsLit lit@(HsChar c)) res_ty + = unifyTauTy res_ty charTy `thenTc_` + returnTc (HsLitOut lit charTy, emptyLIE) -tcExpr (HsLit lit@(HsString str)) - = returnTc (HsLitOut lit stringTy, emptyLIE, stringTy) +tcMonoExpr (HsLit lit@(HsString str)) res_ty + = unifyTauTy res_ty stringTy `thenTc_` + returnTc (HsLitOut lit stringTy, emptyLIE) \end{code} %************************************************************************ @@ -166,21 +279,34 @@ tcExpr (HsLit lit@(HsString str)) %************************************************************************ \begin{code} -tcExpr (HsLam match) - = tcMatch match `thenTc` \ (match',lie,ty) -> - returnTc (HsLam match', lie, ty) +tcMonoExpr (HsPar expr) res_ty -- preserve parens so printing needn't guess where they go + = tcMonoExpr expr res_ty + +-- perform the negate *before* overloading the integer, since the case +-- of minBound on Ints fails otherwise. Could be done elsewhere, but +-- convenient to do it here. + +tcMonoExpr (NegApp (HsLit (HsInt i)) neg) res_ty + = tcMonoExpr (HsLit (HsInt (-i))) res_ty -tcExpr (HsApp e1 e2) = accum e1 [e2] +tcMonoExpr (NegApp expr neg) res_ty + = tcMonoExpr (HsApp neg expr) res_ty + +tcMonoExpr (HsLam match) res_ty + = tcMatchLambda match res_ty `thenTc` \ (match',lie) -> + returnTc (HsLam match', lie) + +tcMonoExpr (HsApp e1 e2) res_ty = accum e1 [e2] where accum (HsApp e1 e2) args = accum e1 (e2:args) accum fun args - = tcApp fun args `thenTc` \ (fun', args', lie, res_ty) -> - returnTc (foldl HsApp fun' args', lie, res_ty) + = tcApp fun args res_ty `thenTc` \ (fun', args', lie) -> + returnTc (foldl HsApp fun' args', lie) -- equivalent to (op e1) e2: -tcExpr (OpApp arg1 op arg2) - = tcApp op [arg1,arg2] `thenTc` \ (op', [arg1', arg2'], lie, res_ty) -> - returnTc (OpApp arg1' op' arg2', lie, res_ty) +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) \end{code} Note that the operators in sections are expected to be binary, and @@ -194,8 +320,8 @@ 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) -> +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 @@ -203,26 +329,21 @@ tcExpr in_expr@(SectionL arg 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_` + unifyFunTy res_ty `thenTc_` - returnTc (SectionL arg' op', lie, res_ty) + returnTc (SectionL arg' op', lie) -- 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) -> - - newTyVarTy mkTypeKind `thenNF_Tc` \ ty1 -> - newTyVarTy mkTypeKind `thenNF_Tc` \ ty2 -> +tcMonoExpr in_expr@(SectionR op expr) res_ty + = tcExpr_id op `thenTc` \ (op', lie1, op_ty) -> tcAddErrCtxt (sectionRAppCtxt in_expr) $ - unifyTauTy op_ty (mkFunTys [ty1, expr_ty] ty2) `thenTc_` - - returnTc (SectionR op' expr', lie1 `plusLIE` lie2, mkFunTy ty1 ty2) + split_fun_ty op_ty 2 {- two args -} `thenTc` \ ([arg1_ty, arg2_ty], op_res_ty) -> + tcMonoExpr expr arg2_ty `thenTc` \ (expr',lie2) -> + unifyTauTy res_ty (mkFunTy arg1_ty op_res_ty) `thenTc_` + returnTc (SectionR op' expr', lie1 `plusLIE` lie2) \end{code} The interesting thing about @ccall@ is that it is just a template @@ -233,237 +354,341 @@ 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) +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 `thenNF_Tc` \ ioTyCon -> let new_arg_dict (arg, arg_ty) - = newDicts (CCallOrigin (_UNPK_ lbl) (Just arg)) - [(cCallableClass, arg_ty)] `thenNF_Tc` \ (arg_dicts, _) -> + = newClassDicts (CCallOrigin (_UNPK_ lbl) (Just arg)) + [(cCallableClass, [arg_ty])] `thenNF_Tc` \ (arg_dicts, _) -> returnNF_Tc arg_dicts -- Actually a singleton bag result_origin = CCallOrigin (_UNPK_ lbl) Nothing {- Not an arg -} in -- Arguments - tcExprs args `thenTc` \ (args', args_lie, arg_tys) -> + let n_args = length args + tv_idxs | n_args == 0 = [] + | otherwise = [1..n_args] + in + mapNF_Tc (\ _ -> newTyVarTy_OpenKind) tv_idxs `thenNF_Tc` \ arg_tys -> + tcMonoExprs args arg_tys `thenTc` \ (args', args_lie) -> -- The argument types can be unboxed or boxed; the result - -- type must, however, be boxed since it's an argument to the PrimIO + -- type must, however, be boxed since it's an argument to the IO -- type constructor. - newTyVarTy mkBoxedTypeKind `thenNF_Tc` \ result_ty -> + newTyVarTy boxedTypeKind `thenNF_Tc` \ result_ty -> + let + io_result_ty = mkTyConApp ioTyCon [result_ty] + [ioDataCon] = tyConDataCons ioTyCon + in + unifyTauTy res_ty io_result_ty `thenTc_` -- Construct the extra insts, which encode the -- constraints on the argument and result types. - mapNF_Tc new_arg_dict (args `zip` arg_tys) `thenNF_Tc` \ ccarg_dicts_s -> - newDicts result_origin [(cReturnableClass, result_ty)] `thenNF_Tc` \ (ccres_dict, _) -> - - returnTc (CCall lbl args' may_gc is_asm result_ty, - 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 -> + newClassDicts result_origin [(cReturnableClass, [result_ty])] `thenNF_Tc` \ (ccres_dict, _) -> + returnTc (HsApp (HsVar (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) \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 predTy boolTy - ) `thenTc_` - - tcExpr b1 `thenTc` \ (b1',lie2,result_ty) -> - tcExpr b2 `thenTc` \ (b2',lie3,b2Ty) -> + tcMonoExpr pred boolTy ) `thenTc` \ (pred',lie1) -> - tcAddErrCtxt (branchCtxt b1 b2) $ - unifyTauTy result_ty b2Ty `thenTc_` - - returnTc (HsIf pred' b1' b2' src_loc, plusLIE lie1 (plusLIE lie2 lie3), result_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} -tcExpr (ListComp expr quals) - = tcListComp expr quals `thenTc` \ ((expr',quals'), lie, ty) -> - returnTc (ListComp expr' quals', lie, ty) +\begin{code} +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 (HsDo stmts src_loc) - = -- get the Monad and MonadZero classes - -- create type consisting of a fresh monad tyvar - tcAddSrcLoc src_loc $ - newTyVarTy monadKind `thenNF_Tc` \ m -> - tcDoStmts False m stmts `thenTc` \ ((stmts',monad,mzero), lie, do_ty) -> +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) + where + tc_elt elt_ty expr + = tcAddErrCtxt (listCtxt expr) $ + tcMonoExpr expr elt_ty + +tcMonoExpr (ExplicitTuple exprs boxed) res_ty + = (if boxed + then unifyTupleTy (length exprs) res_ty + else unifyUnboxedTupleTy (length exprs) res_ty + ) `thenTc` \ arg_tys -> + mapAndUnzipTc (\ (expr, arg_ty) -> tcMonoExpr expr arg_ty) + (exprs `zip` arg_tys) -- we know they're of equal length. + `thenTc` \ (exprs', lies) -> + returnTc (ExplicitTuple exprs' boxed, plusLIEs lies) + +tcMonoExpr expr@(RecordCon con_name rbinds) res_ty + = tcAddErrCtxt (recordConCtxt expr) $ + tcId con_name `thenNF_Tc` \ (con_expr, con_lie, con_tau) -> + let + (_, record_ty) = splitFunTys con_tau + in + -- Con is syntactically constrained to be a data constructor + ASSERT( maybeToBool (splitAlgTyConApp_maybe record_ty ) ) + unifyTauTy res_ty record_ty `thenTc_` - -- create dictionaries for monad and possibly monadzero - (if monad then - tcLookupClassByKey monadClassKey `thenNF_Tc` \ monadClass -> - newDicts DoOrigin [(monadClass, m)] + -- Check that the record bindings match the 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 - returnNF_Tc (emptyLIE, [panic "TcExpr: MonadZero dictionary"]) - ) `thenNF_Tc` \ (m_lie, [m_id]) -> - (if mzero then - tcLookupClassByKey monadZeroClassKey `thenNF_Tc` \ monadZeroClass -> - newDicts DoOrigin [(monadZeroClass, m)] - else - returnNF_Tc (emptyLIE, [panic "TcExpr: MonadZero dictionary"]) - ) `thenNF_Tc` \ (mz_lie, [mz_id]) -> - - returnTc (HsDoOut stmts' m_id mz_id src_loc, - lie `plusLIE` m_lie `plusLIE` mz_lie, - do_ty) - where - monadKind = mkArrowKind mkBoxedTypeKind mkBoxedTypeKind -\end{code} -\begin{code} -tcExpr (ExplicitList []) - = newTyVarTy mkBoxedTypeKind `thenNF_Tc` \ tyvar_ty -> - returnTc (ExplicitListOut tyvar_ty [], emptyLIE, mkListTy tyvar_ty) + -- Typecheck the record bindings + tcRecordBinds record_ty rbinds `thenTc` \ (rbinds', rbinds_lie) -> + + let + missing_s_fields = missingStrictFields rbinds data_con + in + checkTcM (null missing_s_fields) + (mapNF_Tc (addErrTc . missingStrictFieldCon con_name) missing_s_fields `thenNF_Tc_` + returnNF_Tc ()) `thenNF_Tc_` + let + missing_fields = missingFields rbinds data_con + in + checkTcM (not (opt_WarnMissingFields && not (null missing_fields))) + (mapNF_Tc ((warnTc True) . missingFieldCon con_name) missing_fields `thenNF_Tc_` + returnNF_Tc ()) `thenNF_Tc_` + returnTc (RecordConOut data_con con_expr rbinds', con_lie `plusLIE` rbinds_lie) -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) +-- The main complication with RecordUpd is that we need to explicitly +-- handle the *non-updated* fields. Consider: +-- +-- 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 (ExplicitTuple exprs) - = tcExprs exprs `thenTc` \ (exprs', lie, tys) -> - returnTc (ExplicitTuple exprs', lie, mkTupleTy (length tys) tys) +tcMonoExpr expr@(RecordUpd record_expr rbinds) res_ty + = tcAddErrCtxt (recordUpdCtxt expr) $ -tcExpr (RecordCon (HsVar con) rbinds) - = tcId con `thenNF_Tc` \ (con_expr, con_lie, con_tau) -> + -- 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 tcLookupValueMaybe field_names `thenNF_Tc` \ maybe_sel_ids -> let - (_, record_ty) = splitFunTy con_tau + bad_guys = [field_name | (field_name, maybe_sel_id) <- field_names `zip` maybe_sel_ids, + case maybe_sel_id of + Nothing -> True + Just sel_id -> not (isRecordSelector sel_id) + ] in - -- Con is syntactically constrained to be a data constructor - ASSERT( maybeToBool (maybeAppDataTyCon record_ty ) ) - - tcRecordBinds record_ty rbinds `thenTc` \ (rbinds', rbinds_lie) -> + mapNF_Tc (addErrTc . notSelector) bad_guys `thenTc_` + if not (null bad_guys) then + failTc + else + + -- STEP 1 + -- Figure out the tycon and data cons from the first field name + let + (Just sel_id : _) = maybe_sel_ids + (_, tau) = ASSERT( isNotUsgTy (idType sel_id) ) + splitForAllTys (idType sel_id) + Just (data_ty, _) = splitFunTy_maybe tau -- Must succeed since sel_id is a selector + (tycon, _, data_cons) = splitAlgTyConApp data_ty + (con_tyvars, theta, _, _, _, _) = dataConSig (head data_cons) + in + tcInstTyVars con_tyvars `thenNF_Tc` \ (_, result_inst_tys, _) -> - -- Check that the record bindings match the constructor - tcLookupGlobalValue con `thenNF_Tc` \ con_id -> - checkTc (checkRecordFields rbinds con_id) - (badFieldsCon con rbinds) `thenTc_` + -- 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 (RecordCon con_expr rbinds', con_lie `plusLIE` rbinds_lie, record_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 result_record_ty 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 --- 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. --- --- 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. + -- 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 -tcExpr (RecordUpd record_expr rbinds) - = ASSERT( not (null rbinds) ) - tcAddErrCtxt recordUpdCtxt $ + non_upd_field_lbls = concat relevant_field_lbls_s `minusList` upd_field_lbls + common_tyvars = tyVarsOfTypes (map fieldLabelType non_upd_field_lbls) - tcExpr record_expr `thenTc` \ (record_expr', record_lie, record_ty) -> - tcRecordBinds record_ty rbinds `thenTc` \ (rbinds', rbinds_lie) -> + 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 + in + mapNF_Tc mk_inst_ty (zip con_tyvars result_inst_tys) `thenNF_Tc` \ inst_tys -> - -- Check that the field names are plausible - zonkTcType record_ty `thenNF_Tc` \ record_ty' -> + -- STEP 5 + -- Typecheck the expression to be updated let - (tycon, inst_tys, data_cons) = 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) + record_ty = mkTyConApp tycon inst_tys in - tcInstTheta (tyvars `zipEqual` inst_tys) theta `thenNF_Tc` \ theta' -> - newDicts RecordUpdOrigin theta' `thenNF_Tc` \ (con_lie, dicts) -> - checkTc (any (checkRecordFields rbinds) data_cons) - (badFieldsUpd rbinds) `thenTc_` + 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' = substClasses inst_env theta + in + newClassDicts RecordUpdOrigin theta' `thenNF_Tc` \ (con_lie, dicts) -> - returnTc (RecordUpdOut record_expr' dicts rbinds', - con_lie `plusLIE` record_lie `plusLIE` rbinds_lie, - record_ty) + -- Phew! + returnTc (RecordUpdOut record_expr' result_record_ty dicts rbinds', + con_lie `plusLIE` record_lie `plusLIE` rbinds_lie) -tcExpr (ArithSeqIn seq@(From expr)) - = tcExpr expr `thenTc` \ (expr', lie1, ty) -> +tcMonoExpr (ArithSeqIn seq@(From expr)) res_ty + = unifyListTy res_ty `thenTc` \ elt_ty -> + tcMonoExpr expr elt_ty `thenTc` \ (expr', lie1) -> - tcLookupGlobalValueByKey enumFromClassOpKey `thenNF_Tc` \ sel_id -> + tcLookupValueByKey enumFromClassOpKey `thenNF_Tc` \ sel_id -> newMethod (ArithSeqOrigin seq) - (RealId sel_id) [ty] `thenNF_Tc` \ (lie2, enum_from_id) -> + sel_id [elt_ty] `thenNF_Tc` \ (lie2, enum_from_id) -> returnTc (ArithSeqOut (HsVar enum_from_id) (From expr'), - lie1 `plusLIE` lie2, - mkListTy ty) - -tcExpr in_expr@(ArithSeqIn seq@(FromThen expr1 expr2)) - = tcExpr expr1 `thenTc` \ (expr1',lie1,ty1) -> - tcExpr expr2 `thenTc` \ (expr2',lie2,ty2) -> - - tcAddErrCtxt (arithSeqCtxt in_expr) $ - unifyTauTyList [ty1, ty2] `thenTc_` - - tcLookupGlobalValueByKey enumFromThenClassOpKey `thenNF_Tc` \ sel_id -> + lie1 `plusLIE` lie2) + +tcMonoExpr in_expr@(ArithSeqIn seq@(FromThen expr1 expr2)) res_ty + = tcAddErrCtxt (arithSeqCtxt in_expr) $ + unifyListTy res_ty `thenTc` \ elt_ty -> + tcMonoExpr expr1 elt_ty `thenTc` \ (expr1',lie1) -> + tcMonoExpr expr2 elt_ty `thenTc` \ (expr2',lie2) -> + tcLookupValueByKey enumFromThenClassOpKey `thenNF_Tc` \ sel_id -> newMethod (ArithSeqOrigin seq) - (RealId sel_id) [ty1] `thenNF_Tc` \ (lie3, enum_from_then_id) -> + sel_id [elt_ty] `thenNF_Tc` \ (lie3, enum_from_then_id) -> returnTc (ArithSeqOut (HsVar enum_from_then_id) (FromThen expr1' expr2'), - lie1 `plusLIE` lie2 `plusLIE` lie3, - mkListTy ty1) - -tcExpr in_expr@(ArithSeqIn seq@(FromTo expr1 expr2)) - = tcExpr expr1 `thenTc` \ (expr1',lie1,ty1) -> - tcExpr expr2 `thenTc` \ (expr2',lie2,ty2) -> - - tcAddErrCtxt (arithSeqCtxt in_expr) $ - unifyTauTyList [ty1,ty2] `thenTc_` - - tcLookupGlobalValueByKey enumFromToClassOpKey `thenNF_Tc` \ sel_id -> + lie1 `plusLIE` lie2 `plusLIE` lie3) + +tcMonoExpr in_expr@(ArithSeqIn seq@(FromTo expr1 expr2)) res_ty + = tcAddErrCtxt (arithSeqCtxt in_expr) $ + unifyListTy res_ty `thenTc` \ elt_ty -> + tcMonoExpr expr1 elt_ty `thenTc` \ (expr1',lie1) -> + tcMonoExpr expr2 elt_ty `thenTc` \ (expr2',lie2) -> + tcLookupValueByKey enumFromToClassOpKey `thenNF_Tc` \ sel_id -> newMethod (ArithSeqOrigin seq) - (RealId sel_id) [ty1] `thenNF_Tc` \ (lie3, enum_from_to_id) -> + sel_id [elt_ty] `thenNF_Tc` \ (lie3, enum_from_to_id) -> returnTc (ArithSeqOut (HsVar enum_from_to_id) (FromTo expr1' expr2'), - lie1 `plusLIE` lie2 `plusLIE` lie3, - 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 -> + lie1 `plusLIE` lie2 `plusLIE` lie3) + +tcMonoExpr in_expr@(ArithSeqIn seq@(FromThenTo expr1 expr2 expr3)) res_ty + = tcAddErrCtxt (arithSeqCtxt in_expr) $ + unifyListTy res_ty `thenTc` \ elt_ty -> + tcMonoExpr expr1 elt_ty `thenTc` \ (expr1',lie1) -> + tcMonoExpr expr2 elt_ty `thenTc` \ (expr2',lie2) -> + tcMonoExpr expr3 elt_ty `thenTc` \ (expr3',lie3) -> + tcLookupValueByKey enumFromThenToClassOpKey `thenNF_Tc` \ sel_id -> newMethod (ArithSeqOrigin seq) - (RealId sel_id) [ty1] `thenNF_Tc` \ (lie4, eft_id) -> + 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, - mkListTy ty1) + lie1 `plusLIE` lie2 `plusLIE` lie3 `plusLIE` lie4) \end{code} %************************************************************************ @@ -473,33 +698,92 @@ tcExpr in_expr@(ArithSeqIn seq@(FromThenTo expr1 expr2 expr3)) %************************************************************************ \begin{code} -tcExpr in_expr@(ExprWithTySig expr poly_ty) - = tcExpr expr `thenTc` \ (texpr, lie, tau_ty) -> - tcPolyType poly_ty `thenTc` \ sigma_sig -> - - -- Check the tau-type part - tcSetErrCtxt (exprSigCtxt in_expr) $ - tcInstType [] sigma_sig `thenNF_Tc` \ sigma_sig' -> - let - (sig_tyvars', sig_theta', sig_tau') = splitSigmaTy sigma_sig' - in - unifyTauTy tau_ty sig_tau' `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 in_expr@(ExprWithTySig expr poly_ty) res_ty + = tcSetErrCtxt (exprSigCtxt in_expr) $ + tcHsType 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} + +Implicit Parameter bindings. + +\begin{code} +tcMonoExpr (HsWith expr binds) res_ty + = tcMonoExpr expr res_ty `thenTc` \ (expr', lie) -> + tcIPBinds binds `thenTc` \ (binds', types, lie2) -> + partitionLIEbyMeth isBound lie `thenTc` \ (ips, lie') -> + zonkLIE ips `thenTc` \ ips' -> + tcSimplify (text "With!") (tyVarsOfLIE ips') ips' `thenTc` \ res@(_, dict_binds, _) -> + let expr'' = if nullMonoBinds dict_binds + then expr' + else HsLet (MonoBind dict_binds [] NonRecursive) expr' in + tcCheckIPBinds binds' types ips' `thenTc_` + returnTc (HsWith expr'' binds', lie' `plusLIE` lie2) + where isBound p + = case ipName_maybe p of + Just n -> n `elem` names + Nothing -> False + names = map fst binds + +tcIPBinds ((name, expr) : binds) + = newTyVarTy_OpenKind `thenTc` \ ty -> + tcGetSrcLoc `thenTc` \ loc -> + let id = ipToId name ty loc in + tcMonoExpr expr ty `thenTc` \ (expr', lie) -> + zonkTcType ty `thenTc` \ ty' -> + tcIPBinds binds `thenTc` \ (binds', types, lie2) -> + returnTc ((id, expr') : binds', ty : types, lie `plusLIE` lie2) +tcIPBinds [] = returnTc ([], [], emptyLIE) + +tcCheckIPBinds binds types ips + = foldrTc tcCheckIPBind (getIPsOfLIE ips) (zip binds types) + +-- ZZ how do we use the loc? +tcCheckIPBind bt@((v, _), t1) ((n, t2) : ips) | getName v == n + = unifyTauTy t1 t2 `thenTc_` + tcCheckIPBind bt ips `thenTc` \ ips' -> + returnTc ips' +tcCheckIPBind bt (ip : ips) + = tcCheckIPBind bt ips `thenTc` \ ips' -> + returnTc (ip : ips') +tcCheckIPBind bt [] + = returnTc [] +\end{code} + +Typecheck expression which in most cases will be an Id. + +\begin{code} +tcExpr_id :: RenamedHsExpr + -> TcM s (TcExpr, + LIE, + TcType) +tcExpr_id id_expr + = case id_expr of + HsVar name -> tcId name `thenNF_Tc` \ stuff -> + returnTc stuff + other -> newTyVarTy_OpenKind `thenNF_Tc` \ id_ty -> + tcMonoExpr id_expr id_ty `thenTc` \ (id_expr', lie_id) -> + returnTc (id_expr', lie_id, id_ty) \end{code} %************************************************************************ @@ -509,291 +793,188 @@ 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 +tcApp :: RenamedHsExpr -> [RenamedHsExpr] -- Function and args + -> TcType -- Expected result type of application + -> TcM s (TcExpr, [TcExpr], -- Translated fun and args + LIE) + +tcApp fun args res_ty = -- 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) -> + tcExpr_id fun `thenTc` \ (fun', lie_fun, fun_ty) -> - tcApp_help fun 1 fun_ty args `thenTc` \ (args', lie_args, res_ty) -> + tcAddErrCtxt (wrongArgsCtxt "too many" fun args) ( + split_fun_ty fun_ty (length args) + ) `thenTc` \ (expected_arg_tys, actual_result_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_` + -- 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_` - returnTc (fun', args', lie_fun `plusLIE` lie_args, res_ty) + -- 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_` -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 + returnTc (fun', args', lie_fun `plusLIE` plusLIEs lie_args_s) -tcApp_help orig_fun arg_no fun_ty [] - = returnTc ([], emptyLIE, fun_ty) -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) -> +-- 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, _) = 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 + 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 s ([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) - - | 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) - let - (expected_tyvars, expected_theta, expected_tau) = splitSigmaTy expected_arg_ty - in - ASSERT( null expected_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 expected_tau actual_arg_ty `thenTc_` ( +tcArg :: RenamedHsExpr -- The function (for error messages) + -> (RenamedHsExpr, TcType, Int) -- Actual argument and expected arg type + -> TcM s (TcExpr, LIE) -- Resulting argument and LIE - -- 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) $ - tcGetGlobalTyVars `thenNF_Tc` \ env_tyvars -> - zonkTcTyVars (tyVarsOfType expected_arg_ty) `thenNF_Tc` \ free_tyvars -> - checkSigTyVarsGivenGlobals - (env_tyvars `unionTyVarSets` free_tyvars) - expected_tyvars expected_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 expected_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 expected_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} %* * %************************************************************************ +Between the renamer and the first invocation of the UsageSP inference, +identifiers read from interface files will have usage information in +their types, whereas other identifiers will not. The unannotTy here +in @tcId@ prevents this information from pointlessly propagating +further prior to the first usage inference. + \begin{code} -tcId :: RnName -> NF_TcM s (TcExpr s, LIE s, TcType s) +tcId :: Name -> NF_TcM s (TcExpr, LIE, TcType) tcId name = -- Look up the Id and instantiate its type - tcLookupLocalValue name `thenNF_Tc` \ maybe_local -> - - (case maybe_local of - Just tc_id -> let - (tyvars, rho) = splitForAllTy (idType tc_id) - in - tcInstTyVars tyvars `thenNF_Tc` \ (tyvars', arg_tys', tenv) -> - tcInstTcType tenv rho `thenNF_Tc` \ rho' -> - returnNF_Tc (TcId tc_id, arg_tys', rho') - - Nothing -> tcLookupGlobalValue name `thenNF_Tc` \ id -> - let - (tyvars, rho) = splitForAllTy (idType id) - in - tcInstTyVars tyvars `thenNF_Tc` \ (tyvars', arg_tys, tenv) -> - tcInstType tenv rho `thenNF_Tc` \ rho' -> - returnNF_Tc (RealId id, arg_tys, rho') - - ) `thenNF_Tc` \ (tc_id_occ, arg_tys, rho) -> - - -- Is it overloaded? - case splitRhoTy rho of - ([], tau) -> -- Not overloaded, so just make a type application - returnNF_Tc (mkHsTyApp (HsVar tc_id_occ) arg_tys, emptyLIE, tau) - - (theta, tau) -> -- Overloaded, so make a Method inst - newMethodWithGivenTy (OccurrenceOf tc_id_occ) - tc_id_occ arg_tys rho `thenNF_Tc` \ (lie, meth_id) -> - returnNF_Tc (HsVar meth_id, lie, tau) -\end{code} + tcLookupValueMaybe name `thenNF_Tc` \ maybe_local -> + + case maybe_local of + Just tc_id -> instantiate_it (OccurrenceOf tc_id) (HsVar tc_id) (unannotTy (idType tc_id)) + Nothing -> tcLookupValue name `thenNF_Tc` \ id -> + tcInstId id `thenNF_Tc` \ (tyvars, theta, tau) -> + instantiate_it2 (OccurrenceOf id) (HsVar id) tyvars theta tau + where + -- The instantiate_it loop runs round instantiating the Id. + -- It has to be a loop because we are now prepared to entertain + -- types like + -- f:: forall a. Eq a => forall b. Baz b => tau + -- We want to instantiate this to + -- f2::tau {f2 = f1 b (Baz b), f1 = f a (Eq a)} + instantiate_it orig fun ty + = tcInstTcType ty `thenNF_Tc` \ (tyvars, rho) -> + tcSplitRhoTy rho `thenNF_Tc` \ (theta, tau) -> + instantiate_it2 orig fun tyvars theta tau + + instantiate_it2 orig fun tyvars theta tau + = if null theta then -- Is it overloaded? + returnNF_Tc (mkHsTyApp fun arg_tys, emptyLIE, tau) + else + -- Yes, it's overloaded + instOverloadedFun orig fun arg_tys theta tau `thenNF_Tc` \ (fun', lie1) -> + instantiate_it orig fun' tau `thenNF_Tc` \ (expr, lie2, final_tau) -> + returnNF_Tc (expr, lie1 `plusLIE` lie2, final_tau) + + where + arg_tys = mkTyVarTys tyvars +\end{code} %************************************************************************ %* * -\subsection{@tcQuals@ typchecks list comprehension qualifiers} +\subsection{@tcDoStmts@ typechecks a {\em list} of do statements} %* * %************************************************************************ \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) -> - 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 +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 $ -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') + newTyVarTy (mkArrowKind boxedTypeKind boxedTypeKind) `thenNF_Tc` \ m -> + newTyVarTy boxedTypeKind `thenNF_Tc` \ elt_ty -> + unifyTauTy res_ty (mkAppTy m elt_ty) `thenTc_` + + -- If it's a comprehension we're dealing with, + -- force it to be a list comprehension. + -- (as of Haskell 98, monad comprehensions are no more.) + (case do_or_lc of + ListComp -> unifyListTy res_ty `thenTc_` returnTc () + _ -> returnTc ()) `thenTc_` + + tcStmts do_or_lc (mkAppTy m) stmts elt_ty `thenTc` \ (stmts', stmts_lie) -> + + -- Build the then and zero methods in case we need them + -- It's important that "then" and "return" appear just once in the final LIE, + -- not only for typechecker efficiency, but also because otherwise during + -- simplification we end up with silly stuff like + -- then = case d of (t,r) -> t + -- then = then + -- where the second "then" sees that it already exists in the "available" stuff. + -- + tcLookupValueByKey returnMClassOpKey `thenNF_Tc` \ return_sel_id -> + tcLookupValueByKey thenMClassOpKey `thenNF_Tc` \ then_sel_id -> + tcLookupValueByKey failMClassOpKey `thenNF_Tc` \ fail_sel_id -> + newMethod DoOrigin return_sel_id [m] `thenNF_Tc` \ (return_lie, return_id) -> + newMethod DoOrigin then_sel_id [m] `thenNF_Tc` \ (then_lie, then_id) -> + newMethod DoOrigin fail_sel_id [m] `thenNF_Tc` \ (fail_lie, fail_id) -> + let + monad_lie = then_lie `plusLIE` return_lie `plusLIE` fail_lie + in + returnTc (HsDoOut do_or_lc stmts' return_id then_id fail_id res_ty src_loc, + stmts_lie `plusLIE` monad_lie) \end{code} %************************************************************************ %* * -\subsection{@tcDoStmts@ typechecks a {\em list} of do statements} +\subsection{Record bindings} %* * %************************************************************************ -\begin{code} -tcDoStmts :: Bool -- True => require a monad - -> TcType s -- m - -> [RenamedStmt] - -> TcM s (([TcStmt s], - Bool, -- True => Monad - Bool), -- True => MonadZero - LIE s, - TcType s) - -tcDoStmts monad m [stmt@(ExprStmt exp src_loc)] - = tcAddSrcLoc src_loc $ - tcSetErrCtxt (stmtCtxt stmt) $ - tcExpr exp `thenTc` \ (exp', exp_lie, exp_ty) -> - (if monad then - newTyVarTy mkTypeKind `thenNF_Tc` \ a -> - unifyTauTy (mkAppTy m a) exp_ty - else - returnTc () - ) `thenTc_` - returnTc (([ExprStmt exp' src_loc], monad, False), exp_lie, exp_ty) - -tcDoStmts _ m (stmt@(ExprStmt exp src_loc) : stmts) - = tcAddSrcLoc src_loc ( - tcSetErrCtxt (stmtCtxt stmt) ( - tcExpr exp `thenTc` \ (exp', exp_lie, exp_ty) -> - newTyVarTy mkTypeKind `thenNF_Tc` \ a -> - unifyTauTy (mkAppTy m a) exp_ty `thenTc_` - returnTc (ExprStmt exp' src_loc, exp_lie) - )) `thenTc` \ (stmt', stmt_lie) -> - tcDoStmts True m stmts `thenTc` \ ((stmts', _, mzero), stmts_lie, stmts_ty) -> - returnTc ((stmt':stmts', True, mzero), - stmt_lie `plusLIE` stmts_lie, - stmts_ty) - -tcDoStmts _ m (stmt@(BindStmt pat exp src_loc) : stmts) - = tcAddSrcLoc src_loc ( - tcSetErrCtxt (stmtCtxt stmt) ( - tcPat pat `thenTc` \ (pat', pat_lie, pat_ty) -> - tcExpr exp `thenTc` \ (exp', exp_lie, exp_ty) -> - newTyVarTy mkTypeKind `thenNF_Tc` \ a -> - unifyTauTy a pat_ty `thenTc_` - unifyTauTy (mkAppTy m a) exp_ty `thenTc_` - returnTc (BindStmt pat' exp' src_loc, pat_lie `plusLIE` exp_lie, irrefutablePat pat') - )) `thenTc` \ (stmt', stmt_lie, failure_free) -> - tcDoStmts True m stmts `thenTc` \ ((stmts', _, mzero), stmts_lie, stmts_ty) -> - returnTc ((stmt':stmts', True, mzero || not failure_free), - stmt_lie `plusLIE` stmts_lie, - stmts_ty) - -tcDoStmts monad m (LetStmt binds : stmts) - = tcBindsAndThen -- No error context, but a binding group is - combine -- rather a large thing for an error context anyway - binds - (tcDoStmts monad m stmts) - where - combine binds' (stmts', monad, mzero) = ((LetStmt binds' : stmts'), monad, mzero) - -\end{code} - Game plan for record bindings ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ For each binding @@ -818,56 +999,86 @@ we \begin{code} tcRecordBinds - :: TcType s -- Expected type of whole record + :: TcType -- Expected type of whole record -> RenamedRecordBinds - -> TcM s (TcRecordBinds s, LIE s) + -> TcM s (TcRecordBinds, LIE) tcRecordBinds expected_record_ty 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 -> + = tcLookupValue field_label `thenNF_Tc` \ sel_id -> + ASSERT( isRecordSelector sel_id ) + -- This lookup and assertion will surely succeed, because + -- we check that the fields are indeed record selectors + -- before calling tcRecordBinds + tcInstId sel_id `thenNF_Tc` \ (_, _, tau) -> -- Record selectors all have type -- forall a1..an. T a1 .. an -> tau - ASSERT( maybeToBool (getFunTy_maybe tau) ) + ASSERT( maybeToBool (splitFunTy_maybe tau) ) let -- Selector must have type RecordType -> FieldType - Just (record_ty, field_ty) = getFunTy_maybe tau + Just (record_ty, field_ty) = splitFunTy_maybe tau in unifyTauTy expected_record_ty record_ty `thenTc_` - tcArg field_ty rhs `thenTc` \ (rhs', lie) -> - returnTc ((RealId sel_id, rhs', pun_flag), lie) + tcPolyExpr 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) -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 +missingStrictFields rbinds data_con + = [ fn | fn <- strict_field_names, + not (fn `elem` field_names_used) + ] + where + field_names_used = [ field_name | (field_name, _, _) <- rbinds ] + strict_field_names = mapMaybe isStrict field_info + + isStrict (fl, MarkedStrict) = Just (fieldLabelName fl) + isStrict _ = Nothing - ok (field_name, _, _) = any (match (getName field_name)) data_con_fields + field_info = zip (dataConFieldLabels data_con) + (dataConStrictMarks data_con) + +missingFields rbinds data_con + = [ fn | fn <- non_strict_field_names, not (fn `elem` field_names_used) ] + where + field_names_used = [ field_name | (field_name, _, _) <- rbinds ] + + -- missing strict fields have already been flagged as + -- being so, so leave them out here. + non_strict_field_names = mapMaybe isn'tStrict field_info + + isn'tStrict (fl, MarkedStrict) = Nothing + isn'tStrict (fl, _) = Just (fieldLabelName fl) + + field_info = zip (dataConFieldLabels data_con) + (dataConStrictMarks data_con) - match field_name field_label = field_name == fieldLabelName field_label \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 s ([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} @@ -878,76 +1089,91 @@ Errors and contexts Mini-utils: \begin{code} -pp_nest_hang :: String -> Pretty -> Pretty -pp_nest_hang label stuff = ppNest 2 (ppHang (ppStr label) 4 stuff) +pp_nest_hang :: String -> SDoc -> SDoc +pp_nest_hang lbl stuff = nest 2 (hang (text lbl) 4 stuff) \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)] +arithSeqCtxt expr + = hang (ptext SLIT("In an arithmetic sequence:")) 4 (ppr expr) -caseCtxt expr sty - = ppHang (ppStr "In a case expression:") 4 (ppr sty expr) +caseCtxt expr + = hang (ptext SLIT("In the case expression:")) 4 (ppr expr) -exprSigCtxt expr sty - = ppHang (ppStr "In an expression with a type signature:") - 4 (ppr sty expr) +caseScrutCtxt expr + = hang (ptext SLIT("In the scrutinee of a case expression:")) 4 (ppr expr) -listCtxt expr sty - = ppHang (ppStr "In a list expression:") 4 (ppr sty expr) +exprSigCtxt expr + = hang (ptext SLIT("In an expression with a type signature:")) + 4 (ppr expr) -predCtxt expr sty - = ppHang (ppStr "In a predicate expression:") 4 (ppr sty expr) +listCtxt expr + = hang (ptext SLIT("In the list element:")) 4 (ppr expr) -sectionRAppCtxt expr sty - = ppHang (ppStr "In a right section:") 4 (ppr sty expr) +predCtxt expr + = hang (ptext SLIT("In the predicate expression:")) 4 (ppr expr) -sectionLAppCtxt expr sty - = ppHang (ppStr "In a left section:") 4 (ppr sty expr) +sectionRAppCtxt expr + = hang (ptext SLIT("In the right section:")) 4 (ppr expr) -funAppCtxt fun arg_no arg sty - = ppHang (ppCat [ ppStr "In the", speakNth arg_no, ppStr "argument of", ppr sty fun]) - 4 (ppCat [ppStr "namely", ppr sty arg]) +sectionLAppCtxt expr + = hang (ptext SLIT("In the left section:")) 4 (ppr expr) -qualCtxt qual sty - = ppHang (ppStr "In a list-comprehension qualifer:") - 4 (ppr sty qual) +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)) -stmtCtxt stmt sty - = ppHang (ppStr "In a do statement:") - 4 (ppr sty stmt) +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 -tooManyArgsCtxt f sty - = ppHang (ppStr "Too many arguments in an application of the function") - 4 (ppr sty f) +appCtxt fun args + = ptext SLIT("In the application") <+> quotes (ppr the_app) + where + the_app = foldl HsApp fun args -- Used in error messages -lurkingRank2Err fun fun_ty 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"]) +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 sty - = ppHang (ppStr "In a polymorphic function argument:") - 4 (ppSep [ppBeside (ppr sty arg) (ppStr " ::"), - ppr sty expected_arg_ty]) +rank2ArgCtxt arg expected_arg_ty + = ptext SLIT("In a polymorphic function argument:") <+> ppr arg -badFieldsUpd rbinds sty - = ppHang (ppStr "No constructor has all these fields:") - 4 (interpp'SP sty fields) +badFieldsUpd rbinds + = hang (ptext SLIT("No constructor has all these fields:")) + 4 (pprQuotedList fields) where fields = [field | (field, _, _) <- rbinds] -recordUpdCtxt sty = ppStr "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")] -badFieldsCon con rbinds sty - = ppHang (ppBesides [ppStr "Inconsistent constructor:", ppr sty con]) - 4 (ppBesides [ppStr "and fields:", interpp'SP sty fields]) +illegalCcallTyErr isArg ty + = hang (hsep [ptext SLIT("Unacceptable"), arg_or_res, ptext SLIT("type in _ccall_ or _casm_:")]) + 4 (hsep [ppr ty]) where - fields = [field | (field, _, _) <- rbinds] + arg_or_res + | isArg = ptext SLIT("argument") + | otherwise = ptext SLIT("result") + + +missingStrictFieldCon :: Name -> Name -> SDoc +missingStrictFieldCon con field + = hsep [ptext SLIT("Constructor") <+> quotes (ppr con), + ptext SLIT("does not have the required strict field"), quotes (ppr field)] + +missingFieldCon :: Name -> Name -> SDoc +missingFieldCon con field + = hsep [ptext SLIT("Field") <+> quotes (ppr field), + ptext SLIT("is not initialised")] \end{code}