X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;ds=sidebyside;f=ghc%2Fcompiler%2Ftypecheck%2FTcExpr.lhs;h=9c59b43d7414cdc433afd980693c0168c7e20e09;hb=5eb1c77c795f92ed0f4c8023847e9d4be1a4fd0d;hp=15b67291bdaab4944394da158b4b624e430e7e34;hpb=10521d8418fd3a1cf32882718b5bd28992db36fd;p=ghc-hetmet.git diff --git a/ghc/compiler/typecheck/TcExpr.lhs b/ghc/compiler/typecheck/TcExpr.lhs index 15b6729..9c59b43 100644 --- a/ghc/compiler/typecheck/TcExpr.lhs +++ b/ghc/compiler/typecheck/TcExpr.lhs @@ -1,63 +1,84 @@ % -% (c) The GRASP/AQUA Project, Glasgow University, 1992-1995 +% (c) The GRASP/AQUA Project, Glasgow University, 1992-1996 % -\section[TcExpr]{TcExpr} +\section[TcExpr]{Typecheck an expression} \begin{code} #include "HsVersions.h" -module TcExpr ( - tcExpr -#ifdef DPH - , tcExprs -#endif - ) where - -import TcMonad -- typechecking monad machinery -import TcMonadFns ( newPolyTyVarTy, newOpenTyVarTy, - newDict, newMethod, newOverloadedLit, - applyTcSubstAndCollectTyVars, - mkIdsWithPolyTyVarTys - ) -import AbsSyn -- the stuff being typechecked +module TcExpr ( tcExpr ) where +IMP_Ubiq() -import AbsPrel ( intPrimTy, charPrimTy, doublePrimTy, - floatPrimTy, addrPrimTy, addrTy, - boolTy, charTy, stringTy, mkFunTy, mkListTy, - mkTupleTy, mkPrimIoTy -#ifdef DPH - ,mkProcessorTy, mkPodTy,toPodId, - processorClass,pidClass -#endif {- Data Parallel Haskell -} +import HsSyn ( HsExpr(..), Qualifier(..), Stmt(..), + HsBinds(..), Bind(..), MonoBinds(..), + ArithSeqInfo(..), HsLit(..), Sig, GRHSsAndBinds, + Match, Fake, InPat, OutPat, PolyType, + failureFreePat, collectPatBinders ) +import RnHsSyn ( SYN_IE(RenamedHsExpr), SYN_IE(RenamedQual), + SYN_IE(RenamedStmt), SYN_IE(RenamedRecordBinds), + RnName{-instance Outputable-} + ) +import TcHsSyn ( SYN_IE(TcExpr), SYN_IE(TcQual), SYN_IE(TcStmt), + TcIdOcc(..), SYN_IE(TcRecordBinds), + mkHsTyApp ) -import AbsUniType -import E -import CE ( lookupCE ) -import Errors -import GenSpecEtc ( checkSigTyVars ) -import Id ( mkInstId, getIdUniType, Id ) -import Inst -import LIE ( nullLIE, unitLIE, plusLIE, unMkLIE, mkLIE, LIE ) -import ListSetOps ( unionLists ) -import Maybes ( Maybe(..) ) -import TVE ( nullTVE, TVE(..) ) -import Spec ( specId, specTy ) -import TcBinds ( tcLocalBindsAndThen ) +import TcMonad hiding ( rnMtoTcM ) +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 SpecEnv ( SpecEnv ) import TcMatches ( tcMatchesCase, tcMatch ) -import TcPolyType ( tcPolyType ) -import TcQuals ( tcQuals ) +import TcMonoType ( tcPolyType ) +import TcPat ( tcPat ) import TcSimplify ( tcSimplifyAndCheck, tcSimplifyRank2 ) -#ifdef DPH -import TcParQuals -#endif {- Data Parallel Haskell -} -import Unify ( unifyTauTy, unifyTauTyList, unifyTauTyLists ) -import UniqFM ( emptyUFM ) -- profiling, pragmas only -import Unique -- *Key stuff +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 TyVar ( GenTyVar, SYN_IE(TyVarSet), unionTyVarSets, mkTyVarSet ) +import TysPrim ( intPrimTy, charPrimTy, doublePrimTy, + floatPrimTy, addrPrimTy, realWorldTy + ) +import TysWiredIn ( addrTy, + boolTy, charTy, stringTy, mkListTy, + mkTupleTy, mkPrimIoTy, stDataCon + ) +import Unify ( unifyTauTy, unifyTauTyList, unifyTauTyLists, unifyFunTy ) +import Unique ( Unique, cCallableClassKey, cReturnableClassKey, + enumFromClassOpKey, enumFromThenClassOpKey, + enumFromToClassOpKey, enumFromThenToClassOpKey, + thenMClassOpKey, zeroClassOpKey + ) +import Outputable ( interpp'SP ) +import PprType ( GenType, GenTyVar ) -- Instances +import Maybes ( maybeToBool ) +import Pretty import Util +\end{code} -tcExpr :: E -> RenamedExpr -> TcM (TypecheckedExpr, LIE, UniType) +\begin{code} +tcExpr :: RenamedHsExpr -> TcM s (TcExpr s, LIE s, TcType s) \end{code} %************************************************************************ @@ -67,17 +88,16 @@ tcExpr :: E -> RenamedExpr -> TcM (TypecheckedExpr, LIE, UniType) %************************************************************************ \begin{code} -tcExpr e (Var name) - = specId (lookupE_Value e name) `thenNF_Tc` \ stuff@(expr, lie, ty) -> +tcExpr (HsVar name) + = tcId name `thenNF_Tc` \ (expr', lie, res_ty) -> - -- Check that there's no lurking rank-2 polymorphism - -- isTauTy is over-paranoid, because we don't expect - -- any submerged polymorphism other than rank-2 polymorphism + -- 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_` - getSrcLocTc `thenNF_Tc` \ loc -> - checkTc (not (isTauTy ty)) (lurkingRank2Err name ty loc) `thenTc_` - - returnTc stuff + returnTc (expr', lie, res_ty) \end{code} %************************************************************************ @@ -89,75 +109,59 @@ tcExpr e (Var name) Overloaded literals. \begin{code} -tcExpr e (Lit lit@(IntLit i)) - = getSrcLocTc `thenNF_Tc` \ loc -> - newPolyTyVarTy `thenNF_Tc` \ ty -> - let - from_int = lookupE_ClassOpByKey e numClassKey SLIT("fromInt") - from_integer = lookupE_ClassOpByKey e numClassKey SLIT("fromInteger") - in - newOverloadedLit (LiteralOrigin lit loc) - (OverloadedIntegral i from_int from_integer) - ty - `thenNF_Tc` \ over_lit -> +tcExpr (HsLit (HsInt i)) + = newTyVarTy mkBoxedTypeKind `thenNF_Tc` \ ty -> - returnTc (Var (mkInstId over_lit), unitLIE over_lit, ty) + newOverloadedLit (LiteralOrigin (HsInt i)) + (OverloadedIntegral i) + ty `thenNF_Tc` \ (lie, over_lit_id) -> -tcExpr e (Lit lit@(FracLit f)) - = getSrcLocTc `thenNF_Tc` \ loc -> - newPolyTyVarTy `thenNF_Tc` \ ty -> - let - from_rational = lookupE_ClassOpByKey e fractionalClassKey SLIT("fromRational") - in - newOverloadedLit (LiteralOrigin lit loc) - (OverloadedFractional f from_rational) - ty - `thenNF_Tc` \ over_lit -> + returnTc (HsVar over_lit_id, lie, ty) - returnTc (Var (mkInstId over_lit), unitLIE over_lit, ty) +tcExpr (HsLit (HsFrac f)) + = newTyVarTy mkBoxedTypeKind `thenNF_Tc` \ ty -> -tcExpr e (Lit lit@(LitLitLitIn s)) - = getSrcLocTc `thenNF_Tc` \ loc -> - let - -- Get the callable class. Rather turgid and a HACK (ToDo). - ce = getE_CE e - cCallableClass = lookupCE ce (PreludeClass cCallableClassKey bottom) - bottom = panic "tcExpr:LitLitLit" - in - newPolyTyVarTy `thenNF_Tc` \ ty -> - - newDict (LitLitOrigin loc (_UNPK_ s)) cCallableClass ty `thenNF_Tc` \ dict -> + newOverloadedLit (LiteralOrigin (HsFrac f)) + (OverloadedFractional f) + ty `thenNF_Tc` \ (lie, over_lit_id) -> + + returnTc (HsVar over_lit_id, lie, ty) - returnTc (Lit (LitLitLit s ty), mkLIE [dict], 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) \end{code} Primitive literals: \begin{code} -tcExpr e (Lit (CharPrimLit c)) - = returnTc (Lit (CharPrimLit c), nullLIE, charPrimTy) +tcExpr (HsLit lit@(HsCharPrim c)) + = returnTc (HsLitOut lit charPrimTy, emptyLIE, charPrimTy) -tcExpr e (Lit (StringPrimLit s)) - = returnTc (Lit (StringPrimLit s), nullLIE, addrPrimTy) +tcExpr (HsLit lit@(HsStringPrim s)) + = returnTc (HsLitOut lit addrPrimTy, emptyLIE, addrPrimTy) -tcExpr e (Lit (IntPrimLit i)) - = returnTc (Lit (IntPrimLit i), nullLIE, intPrimTy) +tcExpr (HsLit lit@(HsIntPrim i)) + = returnTc (HsLitOut lit intPrimTy, emptyLIE, intPrimTy) -tcExpr e (Lit (FloatPrimLit f)) - = returnTc (Lit (FloatPrimLit f), nullLIE, floatPrimTy) +tcExpr (HsLit lit@(HsFloatPrim f)) + = returnTc (HsLitOut lit floatPrimTy, emptyLIE, floatPrimTy) -tcExpr e (Lit (DoublePrimLit d)) - = returnTc (Lit (DoublePrimLit d), nullLIE, doublePrimTy) +tcExpr (HsLit lit@(HsDoublePrim d)) + = returnTc (HsLitOut lit doublePrimTy, emptyLIE, doublePrimTy) \end{code} Unoverloaded literals: \begin{code} -tcExpr e (Lit (CharLit c)) - = returnTc (Lit (CharLit c), nullLIE, charTy) +tcExpr (HsLit lit@(HsChar c)) + = returnTc (HsLitOut lit charTy, emptyLIE, charTy) -tcExpr e (Lit (StringLit str)) - = returnTc (Lit (StringLit str), nullLIE, stringTy) +tcExpr (HsLit lit@(HsString str)) + = returnTc (HsLitOut lit stringTy, emptyLIE, stringTy) \end{code} %************************************************************************ @@ -167,49 +171,68 @@ tcExpr e (Lit (StringLit str)) %************************************************************************ \begin{code} -tcExpr e (Lam match) - = tcMatch e match `thenTc` \ (match',lie,ty) -> - returnTc (Lam match',lie,ty) +tcExpr (HsPar expr) -- preserve parens so printing needn't guess where they go + = tcExpr expr -tcExpr e (App e1 e2) = accum e1 [e2] - where - accum (App e1 e2) args = accum e1 (e2:args) - accum fun args = tcApp (foldl App) e fun args +tcExpr (NegApp expr neg) = tcExpr (HsApp neg expr) + +tcExpr (HsLam match) + = tcMatch match `thenTc` \ (match',lie,ty) -> + returnTc (HsLam match', lie, 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) -- equivalent to (op e1) e2: -tcExpr e (OpApp e1 op e2) - = tcApp (\fun [arg1,arg2] -> OpApp arg1 fun arg2) e 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) \end{code} Note that the operators in sections are expected to be binary, and a type error will occur if they aren't. \begin{code} --- equivalent to --- \ x -> e op x, +-- Left sections, equivalent to +-- \ x -> e op x, -- or --- \ x -> op e x, +-- \ x -> op e x, -- or just -- op e -tcExpr e (SectionL expr op) - = tcApp (\ fun [arg] -> SectionL arg fun) e op [expr] +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) --- equivalent to \ x -> x op expr, or +-- Right sections, equivalent to \ x -> x op expr, or -- \ x -> op x expr -tcExpr e (SectionR op expr) - = tcExpr e op `thenTc` \ (op', lie1, op_ty) -> - tcExpr e expr `thenTc` \ (expr',lie2, expr_ty) -> - newOpenTyVarTy `thenNF_Tc` \ ty1 -> - newOpenTyVarTy `thenNF_Tc` \ ty2 -> - let - result_ty = mkFunTy ty1 ty2 - in - unifyTauTy op_ty (mkFunTy ty1 (mkFunTy expr_ty ty2)) - (SectionRAppCtxt op expr) `thenTc_` +tcExpr in_expr@(SectionR op expr) + = tcExpr op `thenTc` \ (op', lie1, op_ty) -> + tcExpr expr `thenTc` \ (expr',lie2, expr_ty) -> - returnTc (SectionR op' expr', plusLIE lie1 lie2, result_ty) + newTyVarTy mkTypeKind `thenNF_Tc` \ ty1 -> + newTyVarTy mkTypeKind `thenNF_Tc` \ ty2 -> + tcAddErrCtxt (sectionRAppCtxt in_expr) $ + unifyTauTy (mkFunTys [ty1, expr_ty] ty2) op_ty `thenTc_` + + returnTc (SectionR op' expr', lie1 `plusLIE` lie2, mkFunTy ty1 ty2) \end{code} The interesting thing about @ccall@ is that it is just a template @@ -220,164 +243,215 @@ arg/result types); unify them with the args/result; and store them for later use. \begin{code} -tcExpr e (CCall lbl args may_gc is_asm ignored_fake_result_ty) - = getSrcLocTc `thenNF_Tc` \ src_loc -> - let - -- Get the callable and returnable classes. Rather turgid (ToDo). - ce = getE_CE e - cCallableClass = lookupCE ce (PreludeClass cCallableClassKey bottom) - cReturnableClass = lookupCE ce (PreludeClass cReturnableClassKey bottom) - bottom = panic "tcExpr:CCall" +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 -> - new_arg_dict (arg, arg_ty) = newDict (CCallOrigin src_loc (_UNPK_ lbl) (Just arg)) - cCallableClass arg_ty + let + new_arg_dict (arg, arg_ty) + = newDicts (CCallOrigin (_UNPK_ lbl) (Just arg)) + [(cCallableClass, arg_ty)] `thenNF_Tc` \ (arg_dicts, _) -> + returnNF_Tc arg_dicts -- Actually a singleton bag - result_origin = CCallOrigin src_loc (_UNPK_ lbl) Nothing {- Not an arg -} + result_origin = CCallOrigin (_UNPK_ lbl) Nothing {- Not an arg -} in - + -- Arguments - tcExprs e args `thenTc` \ (args', args_lie, arg_tys) -> + tcExprs args `thenTc` \ (args', args_lie, arg_tys) -> -- 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 PrimIO -- type constructor. - newPolyTyVarTy `thenNF_Tc` \ result_ty -> + newTyVarTy mkBoxedTypeKind `thenNF_Tc` \ result_ty -> -- 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` \ arg_dicts -> - newDict result_origin cReturnableClass result_ty `thenNF_Tc` \ res_dict -> - - returnTc (CCall lbl args' may_gc is_asm result_ty, - args_lie `plusLIE` mkLIE (res_dict : arg_dicts), + 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 (HsCon stDataCon [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) \end{code} \begin{code} -tcExpr e (SCC label expr) - = tcExpr e expr `thenTc` \ (expr', lie, expr_ty) -> +tcExpr (HsSCC label expr) + = tcExpr expr `thenTc` \ (expr', lie, expr_ty) -> -- No unification. Give SCC the type of expr - returnTc (SCC label expr', lie, expr_ty) + returnTc (HsSCC label expr', lie, expr_ty) -tcExpr e (Let binds expr) - = tcLocalBindsAndThen e - Let -- The combiner - binds -- Bindings to check - (\ e -> tcExpr e expr) -- Typechecker for the expression +tcExpr (HsLet binds expr) + = tcBindsAndThen + HsLet -- The combiner + binds -- Bindings to check + (tcExpr expr) -- Typechecker for the expression -tcExpr e (Case expr matches) - = tcExpr e expr `thenTc` \ (expr',lie1,expr_ty) -> - tcMatchesCase e matches `thenTc` \ (matches',lie2,match_ty) -> - newOpenTyVarTy `thenNF_Tc` \ result_ty -> +tcExpr in_expr@(HsCase expr matches src_loc) + = tcAddSrcLoc src_loc $ + tcExpr expr `thenTc` \ (expr',lie1,expr_ty) -> + newTyVarTy mkTypeKind `thenNF_Tc` \ result_ty -> - unifyTauTy (mkFunTy expr_ty result_ty) match_ty - (CaseCtxt expr matches) `thenTc_` + tcAddErrCtxt (caseCtxt in_expr) $ + tcMatchesCase (mkFunTy expr_ty result_ty) matches + `thenTc` \ (matches',lie2) -> - returnTc (Case expr' matches', plusLIE lie1 lie2, result_ty) + returnTc (HsCase expr' matches' src_loc, plusLIE lie1 lie2, result_ty) -tcExpr e (If pred b1 b2) - = tcExpr e pred `thenTc` \ (pred',lie1,predTy) -> +tcExpr (HsIf pred b1 b2 src_loc) + = tcAddSrcLoc src_loc $ + tcExpr pred `thenTc` \ (pred',lie1,predTy) -> - unifyTauTy predTy boolTy (PredCtxt pred) `thenTc_` + tcAddErrCtxt (predCtxt pred) ( + unifyTauTy boolTy predTy + ) `thenTc_` - tcExpr e b1 `thenTc` \ (b1',lie2,result_ty) -> - tcExpr e b2 `thenTc` \ (b2',lie3,b2Ty) -> + tcExpr b1 `thenTc` \ (b1',lie2,result_ty) -> + tcExpr b2 `thenTc` \ (b2',lie3,b2Ty) -> - unifyTauTy result_ty b2Ty (BranchCtxt b1 b2) `thenTc_` + tcAddErrCtxt (branchCtxt b1 b2) $ + unifyTauTy result_ty b2Ty `thenTc_` - returnTc (If pred' b1' b2', plusLIE lie1 (plusLIE lie2 lie3), result_ty) + returnTc (HsIf pred' b1' b2' src_loc, plusLIE lie1 (plusLIE lie2 lie3), result_ty) -tcExpr e (ListComp expr quals) - = mkIdsWithPolyTyVarTys binders `thenNF_Tc` \ lve -> - -- Binders of a list comprehension must be boxed. - let - new_e = growE_LVE e lve - in - tcQuals new_e quals `thenTc` \ (quals',lie1) -> - tcExpr new_e expr `thenTc` \ (expr', lie2, ty) -> - returnTc (ListComp expr' quals', plusLIE lie1 lie2, mkListTy ty) - where - binders = collectQualBinders quals +tcExpr (ListComp expr quals) + = tcListComp expr quals `thenTc` \ ((expr',quals'), lie, ty) -> + returnTc (ListComp expr' quals', lie, ty) \end{code} \begin{code} -tcExpr e (ExplicitList []) - = newPolyTyVarTy `thenNF_Tc` \ tyvar_ty -> - returnTc (ExplicitListOut tyvar_ty [], nullLIE, mkListTy tyvar_ty) +tcExpr expr@(HsDo stmts src_loc) + = tcDoStmts stmts src_loc +\end{code} + +\begin{code} +tcExpr (ExplicitList []) + = newTyVarTy mkBoxedTypeKind `thenNF_Tc` \ tyvar_ty -> + returnTc (ExplicitListOut tyvar_ty [], emptyLIE, mkListTy tyvar_ty) -tcExpr e (ExplicitList exprs) -- Non-empty list - = tcExprs e exprs `thenTc` \ (exprs', lie, tys@(elt_ty:_)) -> - unifyTauTyList tys (ListCtxt exprs) `thenTc_` +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 e (ExplicitTuple exprs) - = tcExprs e exprs `thenTc` \ (exprs', lie, tys) -> +tcExpr (ExplicitTuple exprs) + = tcExprs exprs `thenTc` \ (exprs', lie, tys) -> returnTc (ExplicitTuple exprs', lie, mkTupleTy (length tys) tys) -tcExpr e (ArithSeqIn seq@(From expr)) - = getSrcLocTc `thenNF_Tc` \ loc -> - tcExpr e expr `thenTc` \ (expr', lie, ty) -> +tcExpr (RecordCon (HsVar con) rbinds) + = tcId con `thenNF_Tc` \ (con_expr, con_lie, con_tau) -> let - enum_from_id = lookupE_ClassOpByKey e enumClassKey SLIT("enumFrom") + (_, record_ty) = splitFunTy con_tau in - newMethod (ArithSeqOrigin seq loc) - enum_from_id [ty] `thenNF_Tc` \ enum_from -> + -- Con is syntactically constrained to be a data constructor + ASSERT( maybeToBool (maybeAppDataTyCon record_ty ) ) + + tcRecordBinds record_ty rbinds `thenTc` \ (rbinds', rbinds_lie) -> + + -- Check that the record bindings match the constructor + tcLookupGlobalValue con `thenNF_Tc` \ con_id -> + checkTc (checkRecordFields rbinds con_id) + (badFieldsCon con rbinds) `thenTc_` - returnTc (ArithSeqOut (Var (mkInstId enum_from)) (From expr'), - plusLIE (unitLIE enum_from) lie, - mkListTy ty) + returnTc (RecordCon con_expr rbinds', con_lie `plusLIE` rbinds_lie, record_ty) -tcExpr e (ArithSeqIn seq@(FromThen expr1 expr2)) - = getSrcLocTc `thenNF_Tc` \ loc -> - tcExpr e expr1 `thenTc` \ (expr1',lie1,ty1) -> - tcExpr e expr2 `thenTc` \ (expr2',lie2,ty2) -> +-- 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. - unifyTauTyList [ty1, ty2] (ArithSeqCtxt (ArithSeqIn seq)) `thenTc_` +tcExpr (RecordUpd record_expr rbinds) + = ASSERT( not (null rbinds) ) + tcAddErrCtxt recordUpdCtxt $ + + tcExpr record_expr `thenTc` \ (record_expr', record_lie, record_ty) -> + tcRecordBinds record_ty rbinds `thenTc` \ (rbinds', rbinds_lie) -> + + -- Check that the field names are plausible + zonkTcType record_ty `thenNF_Tc` \ record_ty' -> let - enum_from_then_id = lookupE_ClassOpByKey e enumClassKey SLIT("enumFromThen") + (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) in - newMethod (ArithSeqOrigin seq loc) - enum_from_then_id [ty1] `thenNF_Tc` \ enum_from_then -> + 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) -> + + tcLookupGlobalValueByKey enumFromClassOpKey `thenNF_Tc` \ sel_id -> + newMethod (ArithSeqOrigin seq) + (RealId sel_id) [ty] `thenNF_Tc` \ (lie2, enum_from_id) -> - returnTc (ArithSeqOut (Var (mkInstId enum_from_then)) + 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 -> + newMethod (ArithSeqOrigin seq) + (RealId sel_id) [ty1] `thenNF_Tc` \ (lie3, enum_from_then_id) -> + + returnTc (ArithSeqOut (HsVar enum_from_then_id) (FromThen expr1' expr2'), - (unitLIE enum_from_then) `plusLIE` lie1 `plusLIE` lie2, + lie1 `plusLIE` lie2 `plusLIE` lie3, mkListTy ty1) -tcExpr e (ArithSeqIn seq@(FromTo expr1 expr2)) - = getSrcLocTc `thenNF_Tc` \ loc -> - tcExpr e expr1 `thenTc` \ (expr1',lie1,ty1) -> - tcExpr e expr2 `thenTc` \ (expr2',lie2,ty2) -> +tcExpr in_expr@(ArithSeqIn seq@(FromTo expr1 expr2)) + = tcExpr expr1 `thenTc` \ (expr1',lie1,ty1) -> + tcExpr expr2 `thenTc` \ (expr2',lie2,ty2) -> - unifyTauTyList [ty1,ty2] (ArithSeqCtxt (ArithSeqIn seq)) `thenTc_` - let - enum_from_to_id = lookupE_ClassOpByKey e enumClassKey SLIT("enumFromTo") - in - newMethod (ArithSeqOrigin seq loc) - enum_from_to_id [ty1] `thenNF_Tc` \ enum_from_to -> - returnTc (ArithSeqOut (Var (mkInstId enum_from_to)) - (FromTo expr1' expr2'), - (unitLIE enum_from_to) `plusLIE` lie1 `plusLIE` lie2, + tcAddErrCtxt (arithSeqCtxt in_expr) $ + unifyTauTyList [ty1,ty2] `thenTc_` + + tcLookupGlobalValueByKey enumFromToClassOpKey `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) + (FromTo expr1' expr2'), + lie1 `plusLIE` lie2 `plusLIE` lie3, mkListTy ty1) -tcExpr e (ArithSeqIn seq@(FromThenTo expr1 expr2 expr3)) - = getSrcLocTc `thenNF_Tc` \ loc -> - tcExpr e expr1 `thenTc` \ (expr1',lie1,ty1) -> - tcExpr e expr2 `thenTc` \ (expr2',lie2,ty2) -> - tcExpr e expr3 `thenTc` \ (expr3',lie3,ty3) -> +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) -> - unifyTauTyList [ty1,ty2,ty3] (ArithSeqCtxt (ArithSeqIn seq)) `thenTc_` - let - enum_from_then_to_id = lookupE_ClassOpByKey e enumClassKey SLIT("enumFromThenTo") - in - newMethod (ArithSeqOrigin seq loc) - enum_from_then_to_id [ty1] `thenNF_Tc` \ enum_from_then_to -> + tcAddErrCtxt (arithSeqCtxt in_expr) $ + unifyTauTyList [ty1,ty2,ty3] `thenTc_` - returnTc (ArithSeqOut (Var (mkInstId enum_from_then_to)) + 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'), - (unitLIE enum_from_then_to) `plusLIE` lie1 `plusLIE` lie2 `plusLIE` lie3, - mkListTy ty1) + lie1 `plusLIE` lie2 `plusLIE` lie3 `plusLIE` lie4, + mkListTy ty1) \end{code} %************************************************************************ @@ -387,25 +461,26 @@ tcExpr e (ArithSeqIn seq@(FromThenTo expr1 expr2 expr3)) %************************************************************************ \begin{code} -tcExpr e (ExprWithTySig expr poly_ty) - = tcExpr e expr `thenTc` \ (texpr, lie, tau_ty) -> - babyTcMtoTcM (tcPolyType (getE_CE e) (getE_TCE e) nullTVE poly_ty) `thenTc` \ sigma_sig -> +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 - specTy SignatureOrigin sigma_sig `thenNF_Tc` \ (sig_tyvars, sig_dicts, sig_tau) -> - unifyTauTy tau_ty sig_tau (ExprSigCtxt expr sig_tau) `thenTc_` + 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 - applyTcSubstAndCollectTyVars (tvOfE e) `thenNF_Tc` \ env_tyvars -> - checkSigTyVars env_tyvars sig_tyvars sig_tau tau_ty (ExprSigCtxt expr sig_tau) - `thenTc` \ sig_tyvars' -> + checkSigTyVars sig_tyvars' sig_tau' `thenTc_` -- Check overloading constraints + newDicts SignatureOrigin sig_theta' `thenNF_Tc` \ (sig_dicts, _) -> tcSimplifyAndCheck - False {- Not top level -} - env_tyvars sig_tyvars' - sig_dicts (unMkLIE lie) - (ExprSigCtxt expr sigma_sig) `thenTc_` + (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 @@ -417,281 +492,478 @@ tcExpr e (ExprWithTySig expr poly_ty) %************************************************************************ %* * -\subsection{Data Parallel Expressions (DPH only)} +\subsection{@tcApp@ typchecks an application} %* * %************************************************************************ -Constraints enforced by the Static semantics for ParallelZF -$exp_1$ = << $exp_2$ | quals >> +\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 -\begin{enumerate} -\item The type of the expression $exp_1$ is <<$exp_2$>> -\item The type of $exp_2$ must be in the class {\tt Processor} -\end{enumerate} +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) -> -\begin{code} -#ifdef DPH -tcExpr e (ParallelZF expr quals) - = let binders = collectParQualBinders quals in - mkIdsWithPolyTyVarTys binders `thenNF_Tc` (\ lve -> - let e' = growE_LVE e lve in - tcParQuals e' quals `thenTc` (\ (quals',lie1) -> - tcExpr e' expr `thenTc` (\ (expr', lie2,ty) -> - getSrcLocTc `thenNF_Tc` (\ src_loc -> - if (isProcessorTy ty) then - returnTc (ParallelZF expr' quals', - plusLIE lie1 lie2 , - mkPodTy ty) - else - failTc (podCompLhsError ty src_loc) - )))) -#endif {- Data Parallel Haskell -} -\end{code} + tcApp_help fun 1 fun_ty args `thenTc` \ (args', lie_args, res_ty) -> -Constraints enforced by the Static semantics for Explicit Pods -exp = << $exp_1$ ... $exp_n$>> (where $n >= 0$) + -- 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_` -\begin{enumerate} -\item The type of the all the expressions in the Pod must be the same. -\item The type of an expression in a POD must be in class {\tt Processor} -\end{enumerate} + returnTc (fun', args', lie_fun `plusLIE` lie_args, res_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) + +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) -> + + -- 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) -> + + -- Done + returnTc (arg':args', lie_arg `plusLIE` lie_args, res_ty) -\begin{code} -#ifdef DPH -tcExpr e (ExplicitPodIn exprs) - = panic "Ignoring explicit PODs for the time being" -{- - = tcExprs e exprs `thenTc` (\ (exprs',lie,tys) -> - newPolyTyVarTy `thenNF_Tc` (\ elt_ty -> - newDict processorClass elt_ty `thenNF_Tc` (\ procDict -> - let - procLie = mkLIEFromDicts procDict - in - unifyTauTyList (elt_ty:tys) (PodCtxt exprs) `thenTc_` - - returnTc ((App - (DictApp - (TyApp (Var toPodId) [elt_ty]) - procDict) - (ExplicitListOut elt_ty exprs')), - plusLIE procLie lie, - mkPodTy elt_ty) - ))) -} -#endif {- Data Parallel Haskell -} \end{code} \begin{code} -#ifdef DPH -tcExpr e (ExplicitProcessor exprs expr) - = tcPidExprs e exprs `thenTc` (\ (exprs',lie1,tys) -> - tcExpr e expr `thenTc` (\ (expr',lie2,ty) -> - returnTc (ExplicitProcessor exprs' expr', - plusLIE lie1 lie2, - mkProcessorTy tys ty) - )) -#endif {- Data Parallel Haskell -} +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) + + -- 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 \end{code} %************************************************************************ %* * -\subsection{@tcExprs@ typechecks a {\em list} of expressions} +\subsection{@tcId@ typchecks an identifier occurrence} %* * %************************************************************************ -ToDo: Possibly find a version of a listTc TcM which would pass the -appropriate functions for the LIE. +\begin{code} +tcId :: RnName -> 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 +\end{code} + +%************************************************************************ +%* * +\subsection{@tcQuals@ typechecks list-comprehension qualifiers} +%* * +%************************************************************************ \begin{code} -tcExprs :: E -> [RenamedExpr] -> TcM ([TypecheckedExpr],LIE,[TauType]) +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 -tcExprs e [] = returnTc ([], nullLIE, []) -tcExprs e (expr:exprs) - = tcExpr e expr `thenTc` \ (expr', lie1, ty) -> - tcExprs e exprs `thenTc` \ (exprs', lie2, tys) -> - returnTc (expr':exprs', plusLIE lie1 lie2, ty:tys) +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') \end{code} %************************************************************************ %* * -\subsection{@tcApp@ typchecks an application} +\subsection{@tcDoStmts@ typechecks a {\em list} of do statements} %* * %************************************************************************ \begin{code} -tcApp :: (TypecheckedExpr -> [TypecheckedExpr] -> TypecheckedExpr) -- Result builder - -> E - -> RenamedExpr - -> [RenamedExpr] - -> TcM (TypecheckedExpr, LIE, UniType) - -tcApp build_result_expression e orig_fun arg_exprs - = tcExpr' e orig_fun (length arg_exprs) - `thenTc` \ (fun', lie_fun, fun_ty) -> - unify_fun 1 fun' lie_fun arg_exprs fun_ty - where - -- Used only in the error message - maybe_fun_id = case orig_fun of - Var name -> Just (lookupE_Value e name) - other -> Nothing - - unify_args :: Int -- Current argument number - -> TypecheckedExpr -- Current rebuilt expression - -> LIE -- Corresponding LIE - -> [RenamedExpr] -- Remaining args - -> [TauType] -- Remaining arg types - -> TauType -- result type - -> TcM (TypecheckedExpr, LIE, UniType) - - unify_args arg_no fun lie (arg:args) (arg_ty:arg_tys) fun_res_ty - = tcExpr e arg `thenTc` \ (arg', lie_arg, actual_arg_ty) -> - - -- These applyTcSubstToTy's are just to improve the error message... - applyTcSubstToTy actual_arg_ty `thenNF_Tc` \ actual_arg_ty' -> - applyTcSubstToTy arg_ty `thenNF_Tc` \ arg_ty' -> - let - err_ctxt = FunAppCtxt orig_fun maybe_fun_id arg arg_ty' actual_arg_ty' arg_no - in - matchArgTy e arg_ty' arg' lie_arg actual_arg_ty' err_ctxt - `thenTc` \ (arg'', lie_arg') -> +tcDoStmts stmts src_loc + = -- get the Monad and MonadZero classes + -- create type consisting of a fresh monad tyvar + tcAddSrcLoc src_loc $ + newTyVarTy (mkArrowKind mkBoxedTypeKind mkBoxedTypeKind) `thenNF_Tc` \ m -> + + + -- 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) -> + + 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' + in - unify_args (arg_no+1) (App fun arg'') (lie `plusLIE` lie_arg') args arg_tys fun_res_ty + go stmts `thenTc` \ (stmts', final_lie, final_ty) -> + returnTc (HsDoOut stmts' then_id zero_id src_loc, + final_lie, + final_ty) +\end{code} + +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. + +2. Instantiate this type + +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. + +4. Type check the value using tcArg, passing tau 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 + -> RenamedRecordBinds + -> TcM s (TcRecordBinds s, LIE s) + +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 -> + tcInstId sel_id `thenNF_Tc` \ (_, _, tau) -> - unify_args arg_no fun lie [] arg_tys fun_res_ty - = -- We've run out of actual arguments. Check that none of - -- arg_tys has a for-all at the top. For example, "build" on - -- its own is no good; it must be applied to something. + -- Record selectors all have type + -- forall a1..an. T a1 .. an -> tau + ASSERT( maybeToBool (getFunTy_maybe tau) ) let - result_ty = glueTyArgs arg_tys fun_res_ty + -- Selector must have type RecordType -> FieldType + Just (record_ty, field_ty) = getFunTy_maybe tau in - getSrcLocTc `thenNF_Tc` \ loc -> - checkTc (not (isTauTy result_ty)) - (underAppliedTyErr result_ty loc) `thenTc_` - returnTc (fun, lie, result_ty) + unifyTauTy expected_record_ty record_ty `thenTc_` + tcArg field_ty rhs `thenTc` \ (rhs', lie) -> + returnTc ((RealId sel_id, rhs', pun_flag), lie) - -- When we run out of arg_tys we go back to unify_fun in the hope - -- that our unification work may have shown up some more arguments - unify_args arg_no fun lie args [] fun_res_ty - = unify_fun arg_no fun lie args fun_res_ty +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 - unify_fun :: Int -- Current argument number - -> TypecheckedExpr -- Current rebuilt expression - -> LIE -- Corresponding LIE - -> [RenamedExpr] -- Remaining args - -> TauType -- Remaining function type - -> TcM (TypecheckedExpr, LIE, UniType) - - unify_fun arg_no fun lie args fun_ty - = -- Find out as much as possible about the function - applyTcSubstToTy fun_ty `thenNF_Tc` \ fun_ty' -> + match field_name field_label = field_name == fieldLabelName field_label +\end{code} - -- Now see whether it has any arguments - case (splitTyArgs fun_ty') of +%************************************************************************ +%* * +\subsection{@tcExprs@ typechecks a {\em list} of expressions} +%* * +%************************************************************************ - ([], _) -> -- Function has no arguments left +\begin{code} +tcExprs :: [RenamedHsExpr] -> TcM s ([TcExpr s], LIE s, [TcType s]) - newOpenTyVarTy `thenNF_Tc` \ result_ty -> - tcExprs e args `thenTc` \ (args', lie_args, arg_tys) -> +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) +\end{code} - -- At this point, a unification error must mean the function is - -- being applied to too many arguments. - unifyTauTy fun_ty' (glueTyArgs arg_tys result_ty) - (TooManyArgsCtxt orig_fun) `thenTc_` - returnTc (build_result_expression fun args', - lie `plusLIE` lie_args, - result_ty) +% ================================================= - (fun_arg_tys, fun_res_ty) -> -- Function has non-empty list of argument types +Errors and contexts +~~~~~~~~~~~~~~~~~~~ - unify_args arg_no fun lie args fun_arg_tys fun_res_ty +Mini-utils: +\begin{code} +pp_nest_hang :: String -> Pretty -> Pretty +pp_nest_hang label stuff = ppNest 2 (ppHang (ppStr label) 4 stuff) \end{code} +Boring and alphabetical: \begin{code} -matchArgTy :: E - -> UniType -- Expected argument type - -> TypecheckedExpr -- Type checked argument - -> LIE -- Actual argument LIE - -> UniType -- Actual argument type - -> UnifyErrContext - -> TcM (TypecheckedExpr, -- The incoming type checked arg, - -- possibly wrapped in a big lambda - LIE) -- Possibly reduced somewhat +arithSeqCtxt expr sty + = ppHang (ppStr "In an arithmetic sequence:") 4 (ppr sty expr) -matchArgTy e expected_arg_ty arg_expr actual_arg_lie actual_arg_ty err_ctxt - | isForAllTy expected_arg_ty - = -- Ha! The argument type of the function is a for-all type, - -- An example of rank-2 polymorphism. +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)] - -- This applyTcSubstToTy is just to improve the error message.. +caseCtxt expr sty + = ppHang (ppStr "In a case expression:") 4 (ppr sty expr) - applyTcSubstToTy actual_arg_ty `thenNF_Tc` \ actual_arg_ty' -> +exprSigCtxt expr sty + = ppHang (ppStr "In an expression with a type signature:") + 4 (ppr sty expr) - -- Instantiate the argument type - -- ToDo: give this a real origin - specTy UnknownOrigin expected_arg_ty `thenNF_Tc` \ (arg_tyvars, arg_lie, arg_tau) -> +listCtxt expr sty + = ppHang (ppStr "In a list expression:") 4 (ppr sty expr) - if not (null arg_lie) then - -- Paranoia check - panic "Non-null overloading in tcApp" - else - -- Assert: arg_lie = [] +predCtxt expr sty + = ppHang (ppStr "In a predicate expression:") 4 (ppr sty expr) - unifyTauTy arg_tau actual_arg_ty' err_ctxt `thenTc_` +sectionRAppCtxt expr sty + = ppHang (ppStr "In a right section:") 4 (ppr sty expr) - -- 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. - applyTcSubstAndCollectTyVars - (tvOfE e `unionLists` - extractTyVarsFromTy expected_arg_ty) `thenNF_Tc` \ free_tyvars -> - checkSigTyVars free_tyvars arg_tyvars arg_tau actual_arg_ty rank2_err_ctxt - `thenTc` \ arg_tyvars' -> - - -- Check that there's no overloading involved - -- Even if there isn't, there may be some Insts which mention the arg_tyvars, - -- but which, on simplification, don't actually need a dictionary involving - -- the tyvar. So we have to do a proper simplification right here. - let insts = unMkLIE actual_arg_lie - in - applyTcSubstToInsts insts `thenNF_Tc` \ insts' -> +sectionLAppCtxt expr sty + = ppHang (ppStr "In a left section:") 4 (ppr sty expr) - tcSimplifyRank2 arg_tyvars' insts' rank2_err_ctxt `thenTc` \ (free_insts, inst_binds) -> +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]) - -- This Let 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 arg_tyvars' (Let (mk_binds inst_binds) arg_expr), mkLIE free_insts) +qualCtxt qual sty + = ppHang (ppStr "In a list-comprehension qualifer:") + 4 (ppr sty qual) - | otherwise - = -- The ordinary, non-rank-2 polymorphic case - unifyTauTy expected_arg_ty actual_arg_ty err_ctxt `thenTc_` - returnTc (arg_expr, actual_arg_lie) +stmtCtxt stmt sty + = ppHang (ppStr "In a do statement:") + 4 (ppr sty stmt) - where - rank2_err_ctxt = Rank2ArgCtxt arg_expr expected_arg_ty +tooManyArgsCtxt f sty + = ppHang (ppStr "Too many arguments in an application of the function") + 4 (ppr sty f) - mk_binds [] = EmptyBinds - mk_binds ((inst,rhs):inst_binds) = (SingleBind (NonRecBind (VarMonoBind (mkInstId inst) rhs))) - `ThenBinds` - mk_binds inst_binds -\end{code} +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"]) -This version only does not check for 2nd order if it is applied. +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]) -\begin{code} -tcExpr' :: E -> RenamedExpr -> Int -> TcM (TypecheckedExpr,LIE,UniType) +badFieldsUpd rbinds sty + = ppHang (ppStr "No constructor has all these fields:") + 4 (interpp'SP sty fields) + where + fields = [field | (field, _, _) <- rbinds] -tcExpr' e v@(Var name) n - | n > 0 = specId (lookupE_Value e name) `thenNF_Tc` \ (expr, lie, ty) -> - returnTc (expr, lie, ty) -tcExpr' e exp n = tcExpr e exp +recordUpdCtxt sty = ppStr "In a record update construct" + +badFieldsCon con rbinds sty + = ppHang (ppBesides [ppStr "Inconsistent constructor:", ppr sty con]) + 4 (ppBesides [ppStr "and fields:", interpp'SP sty fields]) + where + fields = [field | (field, _, _) <- rbinds] \end{code}