X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Fcompiler%2Ftypecheck%2FTcExpr.lhs;h=1eb18f0f01e7dab364a9f5aaa53ba5981bf9fc6c;hb=ce82461fe2c76eb0df07e1f55d743f5d5afcec07;hp=9ae4e040fbd19625732c63a6d6ed510ae6629a72;hpb=f8d1d20eb4779a42e72b6a06c47d6e0f13075bf4;p=ghc-hetmet.git diff --git a/ghc/compiler/typecheck/TcExpr.lhs b/ghc/compiler/typecheck/TcExpr.lhs index 9ae4e04..1eb18f0 100644 --- a/ghc/compiler/typecheck/TcExpr.lhs +++ b/ghc/compiler/typecheck/TcExpr.lhs @@ -20,7 +20,7 @@ import RnHsSyn ( SYN_IE(RenamedHsExpr), SYN_IE(RenamedStmt), SYN_IE(RenamedRecordBinds) ) import TcHsSyn ( SYN_IE(TcExpr), SYN_IE(TcStmt), - TcIdOcc(..), SYN_IE(TcRecordBinds), + SYN_IE(TcRecordBinds), mkHsTyApp ) @@ -34,17 +34,17 @@ import TcEnv ( tcLookupLocalValue, tcLookupGlobalValue, tcLookupClassByKey, tcExtendGlobalTyVars, tcLookupGlobalValueMaybe ) import SpecEnv ( SpecEnv ) -import TcMatches ( tcMatchesCase, tcMatch ) +import TcMatches ( tcMatchesCase, tcMatchExpected ) import TcMonoType ( tcHsType ) import TcPat ( tcPat ) import TcSimplify ( tcSimplifyAndCheck, tcSimplifyRank2 ) -import TcType ( SYN_IE(TcType), TcMaybe(..), +import TcType ( TcIdOcc(..), SYN_IE(TcType), TcMaybe(..), tcInstId, tcInstType, tcInstSigTcType, tcInstTyVars, tcInstSigType, tcInstTcType, tcInstTheta, tcSplitRhoTy, newTyVarTy, newTyVarTys, zonkTcTyVars, zonkTcType ) import TcKind ( TcKind ) -import Class ( SYN_IE(Class), classSig ) +import Class ( SYN_IE(Class) ) import FieldLabel ( FieldLabel, fieldLabelName, fieldLabelType ) import Id ( idType, dataConFieldLabels, dataConSig, recordSelectorFieldLabel, isRecordSelector, @@ -66,7 +66,9 @@ import TysWiredIn ( addrTy, boolTy, charTy, stringTy, mkListTy, mkTupleTy, mkPrimIoTy, stDataCon ) -import Unify ( unifyTauTy, unifyTauTyList, unifyTauTyLists, unifyFunTy ) +import Unify ( unifyTauTy, unifyTauTyList, unifyTauTyLists, + unifyFunTy, unifyListTy, unifyTupleTy + ) import Unique ( Unique, cCallableClassKey, cReturnableClassKey, enumFromClassOpKey, enumFromThenClassOpKey, enumFromToClassOpKey, enumFromThenToClassOpKey, @@ -81,7 +83,9 @@ import Util \end{code} \begin{code} -tcExpr :: RenamedHsExpr -> TcM s (TcExpr s, LIE s, TcType s) +tcExpr :: RenamedHsExpr -- Expession to type check + -> TcType s -- Expected type (could be a type variable) + -> TcM s (TcExpr s, LIE s) \end{code} %************************************************************************ @@ -91,16 +95,17 @@ tcExpr :: RenamedHsExpr -> TcM s (TcExpr s, LIE s, TcType s) %************************************************************************ \begin{code} -tcExpr (HsVar name) - = tcId name `thenNF_Tc` \ (expr', lie, res_ty) -> +tcExpr (HsVar name) res_ty + = tcId name `thenNF_Tc` \ (expr', lie, id_ty) -> + unifyTauTy id_ty res_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} %************************************************************************ @@ -112,59 +117,60 @@ tcExpr (HsVar name) Overloaded literals. \begin{code} -tcExpr (HsLit (HsInt i)) - = newTyVarTy mkBoxedTypeKind `thenNF_Tc` \ ty -> - - newOverloadedLit (LiteralOrigin (HsInt i)) +tcExpr (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)) +tcExpr (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)) +tcExpr (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) + [(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) +tcExpr (HsLit lit@(HsCharPrim c)) res_ty + = unifyTauTy charPrimTy res_ty `thenTc_` + returnTc (HsLitOut lit charPrimTy, emptyLIE) -tcExpr (HsLit lit@(HsStringPrim s)) - = returnTc (HsLitOut lit addrPrimTy, emptyLIE, addrPrimTy) +tcExpr (HsLit lit@(HsStringPrim s)) res_ty + = unifyTauTy addrPrimTy res_ty `thenTc_` + returnTc (HsLitOut lit addrPrimTy, emptyLIE) -tcExpr (HsLit lit@(HsIntPrim i)) - = returnTc (HsLitOut lit intPrimTy, emptyLIE, intPrimTy) +tcExpr (HsLit lit@(HsIntPrim i)) res_ty + = unifyTauTy intPrimTy res_ty `thenTc_` + returnTc (HsLitOut lit intPrimTy, emptyLIE) -tcExpr (HsLit lit@(HsFloatPrim f)) - = returnTc (HsLitOut lit floatPrimTy, emptyLIE, floatPrimTy) +tcExpr (HsLit lit@(HsFloatPrim f)) res_ty + = unifyTauTy floatPrimTy res_ty `thenTc_` + returnTc (HsLitOut lit floatPrimTy, emptyLIE) -tcExpr (HsLit lit@(HsDoublePrim d)) - = returnTc (HsLitOut lit doublePrimTy, emptyLIE, doublePrimTy) +tcExpr (HsLit lit@(HsDoublePrim d)) res_ty + = unifyTauTy doublePrimTy res_ty `thenTc_` + returnTc (HsLitOut lit doublePrimTy, emptyLIE) \end{code} Unoverloaded literals: \begin{code} -tcExpr (HsLit lit@(HsChar c)) - = returnTc (HsLitOut lit charTy, emptyLIE, charTy) +tcExpr (HsLit lit@(HsChar c)) res_ty + = unifyTauTy charTy res_ty `thenTc_` + returnTc (HsLitOut lit charTy, emptyLIE) -tcExpr (HsLit lit@(HsString str)) - = returnTc (HsLitOut lit stringTy, emptyLIE, stringTy) +tcExpr (HsLit lit@(HsString str)) res_ty + = unifyTauTy stringTy res_ty `thenTc_` + returnTc (HsLitOut lit stringTy, emptyLIE) \end{code} %************************************************************************ @@ -174,26 +180,26 @@ tcExpr (HsLit lit@(HsString str)) %************************************************************************ \begin{code} -tcExpr (HsPar expr) -- preserve parens so printing needn't guess where they go - = tcExpr expr +tcExpr (HsPar expr) res_ty -- preserve parens so printing needn't guess where they go + = tcExpr expr res_ty -tcExpr (NegApp expr neg) = tcExpr (HsApp neg expr) +tcExpr (NegApp expr neg) res_ty = tcExpr (HsApp neg expr) res_ty -tcExpr (HsLam match) - = tcMatch match `thenTc` \ (match',lie,ty) -> - returnTc (HsLam match', lie, ty) +tcExpr (HsLam match) res_ty + = tcMatchExpected res_ty match `thenTc` \ (match',lie) -> + returnTc (HsLam match', lie) -tcExpr (HsApp e1 e2) = accum e1 [e2] +tcExpr (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 fix arg2) - = tcApp op [arg1,arg2] `thenTc` \ (op', [arg1', arg2'], lie, res_ty) -> - returnTc (OpApp arg1' op' fix arg2', lie, res_ty) +tcExpr (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 @@ -207,8 +213,8 @@ 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) -> +tcExpr 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 @@ -216,26 +222,21 @@ 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 -> +tcExpr in_expr@(SectionR op expr) res_ty + = tcExpr_id op `thenTc` \ (op', lie1, op_ty) -> tcAddErrCtxt (sectionRAppCtxt in_expr) $ - unifyTauTy (mkFunTys [ty1, expr_ty] ty2) op_ty `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) -> + tcExpr expr arg2_ty `thenTc` \ (expr',lie2) -> + unifyTauTy (mkFunTy arg1_ty op_res_ty) res_ty `thenTc_` + returnTc (SectionR op' expr', lie1 `plusLIE` lie2) \end{code} The interesting thing about @ccall@ is that it is just a template @@ -246,7 +247,7 @@ 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) +tcExpr (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 -> @@ -261,101 +262,97 @@ tcExpr (CCall lbl args may_gc is_asm ignored_fake_result_ty) in -- Arguments - tcExprs args `thenTc` \ (args', args_lie, arg_tys) -> + mapNF_Tc (\ _ -> newTyVarTy mkTypeKind) [1..(length args)] `thenNF_Tc` \ ty_vars -> + tcExprs args ty_vars `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 constructor. newTyVarTy mkBoxedTypeKind `thenNF_Tc` \ result_ty -> + unifyTauTy (mkPrimIoTy result_ty) res_ty `thenTc_` -- Construct the extra insts, which encode the -- constraints on the argument and result types. - mapNF_Tc new_arg_dict (zipEqual "tcExpr:CCall" args arg_tys) `thenNF_Tc` \ ccarg_dicts_s -> + mapNF_Tc new_arg_dict (zipEqual "tcExpr:CCall" args ty_vars) `thenNF_Tc` \ ccarg_dicts_s -> newDicts result_origin [(cReturnableClass, result_ty)] `thenNF_Tc` \ (ccres_dict, _) -> returnTc (HsApp (HsVar (RealId stDataCon) `TyApp` [realWorldTy, result_ty]) (CCall lbl args' may_gc is_asm result_ty), -- do the wrapping in the newtype constructor here - foldr plusLIE ccres_dict ccarg_dicts_s `plusLIE` args_lie, - mkPrimIoTy result_ty) + 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) +tcExpr (HsSCC label expr) res_ty + = tcExpr expr res_ty `thenTc` \ (expr', lie) -> + returnTc (HsSCC label expr', lie) -tcExpr (HsLet binds expr) +tcExpr (HsLet binds expr) res_ty = tcBindsAndThen combiner binds -- Bindings to check - (tc_expr expr) `thenTc` \ ((expr', ty), lie) -> - returnTc (expr', lie, ty) + (tc_expr) `thenTc` \ (expr', lie) -> + returnTc (expr', lie) where - tc_expr expr = tcExpr expr `thenTc` \ (expr', lie, ty) -> - returnTc ((expr',ty), lie) - combiner bind (expr, ty) = (HsLet bind expr, ty) + tc_expr = tcExpr expr res_ty `thenTc` \ (expr', lie) -> + returnTc (expr', lie) + combiner is_rec bind expr = HsLet (MonoBind bind [] is_rec) expr -tcExpr in_expr@(HsCase expr matches src_loc) +tcExpr in_expr@(HsCase expr matches src_loc) res_ty = tcAddSrcLoc src_loc $ - tcExpr expr `thenTc` \ (expr',lie1,expr_ty) -> - newTyVarTy mkTypeKind `thenNF_Tc` \ result_ty -> + newTyVarTy mkTypeKind `thenNF_Tc` \ expr_ty -> + tcExpr expr expr_ty `thenTc` \ (expr',lie1) -> tcAddErrCtxt (caseCtxt in_expr) $ - tcMatchesCase (mkFunTy expr_ty result_ty) matches + tcMatchesCase (mkFunTy expr_ty res_ty) matches `thenTc` \ (matches',lie2) -> - returnTc (HsCase expr' matches' src_loc, plusLIE lie1 lie2, result_ty) + returnTc (HsCase expr' matches' src_loc, plusLIE lie1 lie2) -tcExpr (HsIf pred b1 b2 src_loc) +tcExpr (HsIf pred b1 b2 src_loc) res_ty = tcAddSrcLoc src_loc $ - tcExpr pred `thenTc` \ (pred',lie1,predTy) -> - tcAddErrCtxt (predCtxt pred) ( - unifyTauTy boolTy predTy - ) `thenTc_` - - tcExpr b1 `thenTc` \ (b1',lie2,result_ty) -> - tcExpr b2 `thenTc` \ (b2',lie3,b2Ty) -> + tcExpr 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) + tcExpr b1 res_ty `thenTc` \ (b1',lie2) -> + tcExpr b2 res_ty `thenTc` \ (b2',lie3) -> + returnTc (HsIf pred' b1' b2' src_loc, plusLIE lie1 (plusLIE lie2 lie3)) \end{code} \begin{code} -tcExpr expr@(HsDo do_or_lc stmts src_loc) - = tcDoStmts do_or_lc stmts src_loc +tcExpr expr@(HsDo do_or_lc stmts src_loc) res_ty + = tcDoStmts do_or_lc stmts src_loc res_ty \end{code} \begin{code} -tcExpr (ExplicitList []) - = newTyVarTy mkBoxedTypeKind `thenNF_Tc` \ tyvar_ty -> - returnTc (ExplicitListOut tyvar_ty [], emptyLIE, mkListTy tyvar_ty) - - -tcExpr in_expr@(ExplicitList exprs) -- Non-empty list - = tcExprs exprs `thenTc` \ (exprs', lie, tys@(elt_ty:_)) -> - tcAddErrCtxt (listCtxt in_expr) $ - unifyTauTyList tys `thenTc_` - returnTc (ExplicitListOut elt_ty exprs', lie, mkListTy elt_ty) - -tcExpr (ExplicitTuple exprs) - = tcExprs exprs `thenTc` \ (exprs', lie, tys) -> - returnTc (ExplicitTuple exprs', lie, mkTupleTy (length tys) tys) - -tcExpr (RecordCon (HsVar con) rbinds) - = tcId con `thenNF_Tc` \ (con_expr, con_lie, con_tau) -> +tcExpr 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) $ + tcExpr expr elt_ty + +tcExpr (ExplicitTuple exprs) res_ty + = unifyTupleTy (length exprs) res_ty `thenTc` \ arg_tys -> + mapAndUnzipTc (\ (expr, arg_ty) -> tcExpr expr arg_ty) + (exprs `zip` arg_tys) -- we know they're of equal length. + `thenTc` \ (exprs', lies) -> + returnTc (ExplicitTuple exprs', plusLIEs lies) + +tcExpr (RecordCon con rbinds) res_ty + = tcLookupGlobalValue con `thenNF_Tc` \ con_id -> + tcId con `thenNF_Tc` \ (con_expr, con_lie, con_tau) -> let (_, record_ty) = splitFunTy con_tau in -- Con is syntactically constrained to be a data constructor ASSERT( maybeToBool (maybeAppDataTyCon record_ty ) ) + unifyTauTy record_ty res_ty `thenTc_` -- Check that the record bindings match the constructor - tcLookupGlobalValue con `thenNF_Tc` \ con_id -> let bad_fields = badFields rbinds con_id in @@ -366,7 +363,7 @@ tcExpr (RecordCon (HsVar con) rbinds) -- doesn't match the constructor.) tcRecordBinds record_ty rbinds `thenTc` \ (rbinds', rbinds_lie) -> - returnTc (RecordCon con_expr rbinds', con_lie `plusLIE` rbinds_lie, record_ty) + returnTc (RecordConOut (RealId con_id) con_expr rbinds', con_lie `plusLIE` rbinds_lie) -- The main complication with RecordUpd is that we need to explicitly @@ -395,7 +392,7 @@ tcExpr (RecordCon (HsVar con) rbinds) -- -- All this is done in STEP 4 below. -tcExpr (RecordUpd record_expr rbinds) +tcExpr (RecordUpd record_expr rbinds) res_ty = tcAddErrCtxt recordUpdCtxt $ -- STEP 1 @@ -428,6 +425,7 @@ tcExpr (RecordUpd record_expr rbinds) let result_record_ty = applyTyCon tycon result_inst_tys in + unifyTauTy result_record_ty res_ty `thenTc_` tcRecordBinds result_record_ty rbinds `thenTc` \ (rbinds', rbinds_lie) -> -- STEP 4 @@ -456,9 +454,10 @@ tcExpr (RecordUpd record_expr rbinds) -- STEP 5 -- Typecheck the expression to be updated - tcExpr record_expr `thenTc` \ (record_expr', record_lie, record_ty) -> - unifyTauTy (applyTyCon tycon inst_tys) record_ty `thenTc_` - + let + record_ty = applyTyCon tycon inst_tys + in + tcExpr record_expr record_ty `thenTc` \ (record_expr', record_lie) -> -- STEP 6 -- Figure out the LIE we need. We have to generate some @@ -478,69 +477,58 @@ tcExpr (RecordUpd record_expr rbinds) -- Phew! returnTc (RecordUpdOut record_expr' result_record_ty dicts rbinds', - con_lie `plusLIE` record_lie `plusLIE` rbinds_lie, - result_record_ty) - + con_lie `plusLIE` record_lie `plusLIE` rbinds_lie) -tcExpr (ArithSeqIn seq@(From expr)) - = tcExpr expr `thenTc` \ (expr', lie1, ty) -> +tcExpr (ArithSeqIn seq@(From expr)) res_ty + = unifyListTy res_ty `thenTc` \ elt_ty -> + tcExpr expr elt_ty `thenTc` \ (expr', lie1) -> tcLookupGlobalValueByKey enumFromClassOpKey `thenNF_Tc` \ sel_id -> newMethod (ArithSeqOrigin seq) - (RealId sel_id) [ty] `thenNF_Tc` \ (lie2, enum_from_id) -> + (RealId 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_` + lie1 `plusLIE` lie2) +tcExpr in_expr@(ArithSeqIn seq@(FromThen expr1 expr2)) res_ty + = tcAddErrCtxt (arithSeqCtxt in_expr) $ + unifyListTy res_ty `thenTc` \ elt_ty -> + tcExpr expr1 elt_ty `thenTc` \ (expr1',lie1) -> + tcExpr expr2 elt_ty `thenTc` \ (expr2',lie2) -> tcLookupGlobalValueByKey enumFromThenClassOpKey `thenNF_Tc` \ sel_id -> newMethod (ArithSeqOrigin seq) - (RealId sel_id) [ty1] `thenNF_Tc` \ (lie3, enum_from_then_id) -> + (RealId 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_` + lie1 `plusLIE` lie2 `plusLIE` lie3) +tcExpr in_expr@(ArithSeqIn seq@(FromTo expr1 expr2)) res_ty + = tcAddErrCtxt (arithSeqCtxt in_expr) $ + unifyListTy res_ty `thenTc` \ elt_ty -> + tcExpr expr1 elt_ty `thenTc` \ (expr1',lie1) -> + tcExpr expr2 elt_ty `thenTc` \ (expr2',lie2) -> tcLookupGlobalValueByKey enumFromToClassOpKey `thenNF_Tc` \ sel_id -> newMethod (ArithSeqOrigin seq) - (RealId sel_id) [ty1] `thenNF_Tc` \ (lie3, enum_from_to_id) -> + (RealId 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_` - + lie1 `plusLIE` lie2 `plusLIE` lie3) + +tcExpr in_expr@(ArithSeqIn seq@(FromThenTo expr1 expr2 expr3)) res_ty + = tcAddErrCtxt (arithSeqCtxt in_expr) $ + unifyListTy res_ty `thenTc` \ elt_ty -> + tcExpr expr1 elt_ty `thenTc` \ (expr1',lie1) -> + tcExpr expr2 elt_ty `thenTc` \ (expr2',lie2) -> + tcExpr expr3 elt_ty `thenTc` \ (expr3',lie3) -> tcLookupGlobalValueByKey enumFromThenToClassOpKey `thenNF_Tc` \ sel_id -> newMethod (ArithSeqOrigin seq) - (RealId sel_id) [ty1] `thenNF_Tc` \ (lie4, eft_id) -> + (RealId sel_id) [elt_ty] `thenNF_Tc` \ (lie4, eft_id) -> returnTc (ArithSeqOut (HsVar eft_id) (FromThenTo expr1' expr2' expr3'), - lie1 `plusLIE` lie2 `plusLIE` lie3 `plusLIE` lie4, - mkListTy ty1) + lie1 `plusLIE` lie2 `plusLIE` lie3 `plusLIE` lie4) \end{code} %************************************************************************ @@ -550,19 +538,21 @@ 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) -> +tcExpr in_expr@(ExprWithTySig expr poly_ty) res_ty + = tcSetErrCtxt (exprSigCtxt in_expr) $ tcHsType poly_ty `thenTc` \ sigma_sig -> -- Check the tau-type part - tcSetErrCtxt (exprSigCtxt in_expr) $ tcInstSigType sigma_sig `thenNF_Tc` \ sigma_sig' -> let (sig_tyvars', sig_theta', sig_tau') = splitSigmaTy sigma_sig' in - unifyTauTy sig_tau' tau_ty `thenTc_` - -- Check the type variables of the signature + -- Type check the expression, expecting the signature type + tcExpr expr sig_tau' `thenTc` \ (texpr, lie) -> + + -- Check the type variables of the signature, + -- *after* typechecking the expression checkSigTyVars sig_tyvars' sig_tau' `thenTc_` -- Check overloading constraints @@ -571,12 +561,36 @@ tcExpr in_expr@(ExprWithTySig expr poly_ty) (mkTyVarSet sig_tyvars') sig_dicts lie `thenTc_` + -- 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 sig_tau' res_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, except for any default -- resolution it may have done, which is recorded in the -- substitution. - returnTc (texpr, lie, tau_ty) + returnTc (texpr, lie) + +\end{code} + +Typecheck expression which in most cases will be an Id. + +\begin{code} +tcExpr_id :: RenamedHsExpr + -> TcM s (TcExpr s, + LIE s, + TcType s) +tcExpr_id id_expr + = case id_expr of + HsVar name -> tcId name `thenNF_Tc` \ stuff -> + returnTc stuff + other -> newTyVarTy mkTypeKind `thenNF_Tc` \ id_ty -> + tcExpr id_expr id_ty `thenTc` \ (id_expr', lie_id) -> + returnTc (id_expr', lie_id, id_ty) \end{code} %************************************************************************ @@ -586,70 +600,65 @@ tcExpr in_expr@(ExprWithTySig expr poly_ty) %************************************************************************ \begin{code} + tcApp :: RenamedHsExpr -> [RenamedHsExpr] -- Function and args + -> TcType s -- Expected result type of application -> TcM s (TcExpr s, [TcExpr s], -- Translated fun and args - LIE s, - TcType s) -- Type of the application + LIE s) -tcApp fun args +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) -> + + tcAddErrCtxt (tooManyArgsCtxt fun) ( + split_fun_ty fun_ty (length args) + ) `thenTc` \ (expected_arg_tys, actual_result_ty) -> - tcApp_help fun 1 fun_ty args `thenTc` \ (args', lie_args, res_ty) -> + -- Unify with expected result before type-checking the args + unifyTauTy res_ty actual_result_ty `thenTc_` + + -- Now typecheck the args + mapAndUnzipTc (tcArg fun) + (zip3 args expected_arg_tys [1..]) `thenTc` \ (args', lie_args_s) -> -- Check that the result type doesn't have any nested for-alls. -- For example, a "build" on its own is no good; it must be applied to something. - checkTc (isTauTy res_ty) - (lurkingRank2Err fun fun_ty) `thenTc_` + checkTc (isTauTy actual_result_ty) + (lurkingRank2Err fun fun_ty) `thenTc_` - returnTc (fun', args', lie_fun `plusLIE` lie_args, res_ty) + returnTc (fun', args', lie_fun `plusLIE` plusLIEs lie_args_s) -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 +split_fun_ty :: TcType s -- The type of the function + -> Int -- Number of arguments + -> TcM s ([TcType s], -- Function argument types + TcType s) -- Function result types -tcApp_help orig_fun arg_no fun_ty [] - = returnTc ([], emptyLIE, fun_ty) +split_fun_ty fun_ty 0 + = returnTc ([], fun_ty) -tcApp_help orig_fun arg_no fun_ty all_args@(arg:args) +split_fun_ty fun_ty n = -- 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) - + 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 +tcArg :: RenamedHsExpr -- The function (for error messages) + -> (RenamedHsExpr, TcType s, Int) -- Actual argument and expected arg type -> TcM s (TcExpr s, LIE s) -- Resulting argument and LIE +tcArg the_fun (arg, expected_arg_ty, arg_no) + = tcAddErrCtxt (funAppCtxt the_fun arg arg_no) $ + tcPolyExpr arg expected_arg_ty + -tcArg expected_arg_ty arg +-- tcPolyExpr is like tcExpr, except that the expected type +-- can be a polymorphic one. +tcPolyExpr arg expected_arg_ty | 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) + tcExpr arg expected_arg_ty | otherwise = -- Ha! The argument type of the function is a for-all type, @@ -670,8 +679,7 @@ tcArg expected_arg_ty arg 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_` + tcExpr arg sig_tau `thenTc` \ (arg', lie_arg) -> -- Check that the arg_tyvars havn't been constrained -- The interesting bit here is that we must include the free variables @@ -761,7 +769,7 @@ tcId name %************************************************************************ \begin{code} -tcDoStmts do_or_lc stmts src_loc +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) ) @@ -778,7 +786,8 @@ tcDoStmts do_or_lc stmts src_loc combine_stmts stmt _ ([], _) = panic "Bad last stmt tcDoStmts" combine_stmts stmt _ (stmts, ty) = (stmt:stmts, ty) in - tc_stmts stmts `thenTc` \ ((stmts', result_ty), final_lie) -> + tc_stmts stmts `thenTc` \ ((stmts', result_ty), final_lie) -> + unifyTauTy result_ty res_ty `thenTc_` -- 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, @@ -806,13 +815,13 @@ tcDoStmts do_or_lc stmts src_loc failure_free (GuardStmt _ _) = False failure_free other_stmt = True in - returnTc (HsDoOut do_or_lc stmts' return_id then_id zero_id result_ty src_loc, - final_lie `plusLIE` monad_lie, - result_ty) + returnTc (HsDoOut do_or_lc stmts' return_id then_id zero_id res_ty src_loc, + final_lie `plusLIE` monad_lie) + \end{code} \begin{code} -tcStmt :: (RenamedHsExpr -> TcM s (TcExpr s, LIE s, TcType s)) -- This is tcExpr +tcStmt :: (RenamedHsExpr -> TcType s -> TcM s (TcExpr s, LIE s)) -- This is tcExpr -- The sole, disgusting, reason for this parameter -- is to get the effect of polymorphic recursion -- ToDo: rm when booting with Haskell 1.3 @@ -824,9 +833,10 @@ tcStmt :: (RenamedHsExpr -> TcM s (TcExpr s, LIE s, TcType s)) -- This is tcExpr -> TcM s (thing, LIE s) tcStmt tc_expr do_or_lc m combine stmt@(ReturnStmt exp) do_next - = ASSERT( case do_or_lc of { DoStmt -> False; ListComp -> True } ) + = ASSERT( case do_or_lc of { DoStmt -> False; ListComp -> True; Guard -> True } ) tcSetErrCtxt (stmtCtxt do_or_lc stmt) ( - tc_expr exp `thenTc` \ (exp', exp_lie, exp_ty) -> + newTyVarTy mkTypeKind `thenNF_Tc` \ exp_ty -> + tc_expr exp exp_ty `thenTc` \ (exp', exp_lie) -> returnTc (ReturnStmt exp', exp_lie, m exp_ty) ) `thenTc` \ (stmt', stmt_lie, stmt_ty) -> do_next `thenTc` \ (thing', thing_lie) -> @@ -834,11 +844,11 @@ tcStmt tc_expr do_or_lc m combine stmt@(ReturnStmt exp) do_next stmt_lie `plusLIE` thing_lie) tcStmt tc_expr do_or_lc m combine stmt@(GuardStmt exp src_loc) do_next - = ASSERT( case do_or_lc of { DoStmt -> False; ListComp -> True } ) + = ASSERT( case do_or_lc of { DoStmt -> False; ListComp -> True; Guard -> True } ) + newTyVarTy mkTypeKind `thenNF_Tc` \ exp_ty -> tcAddSrcLoc src_loc ( tcSetErrCtxt (stmtCtxt do_or_lc stmt) ( - tc_expr exp `thenTc` \ (exp', exp_lie, exp_ty) -> - unifyTauTy boolTy exp_ty `thenTc_` + tc_expr exp boolTy `thenTc` \ (exp', exp_lie) -> returnTc (GuardStmt exp' src_loc, exp_lie) )) `thenTc` \ (stmt', stmt_lie) -> do_next `thenTc` \ (thing', thing_lie) -> @@ -846,13 +856,16 @@ tcStmt tc_expr do_or_lc m combine stmt@(GuardStmt exp src_loc) do_next stmt_lie `plusLIE` thing_lie) tcStmt tc_expr do_or_lc m combine stmt@(ExprStmt exp src_loc) do_next - = ASSERT( case do_or_lc of { DoStmt -> True; ListComp -> False } ) + = ASSERT( case do_or_lc of { DoStmt -> True; ListComp -> False; Guard -> False } ) + newTyVarTy mkTypeKind `thenNF_Tc` \ exp_ty -> tcAddSrcLoc src_loc ( tcSetErrCtxt (stmtCtxt do_or_lc stmt) ( - tc_expr exp `thenTc` \ (exp', exp_lie, exp_ty) -> - -- Check that exp has type (m tau) for some tau (doesn't matter what) newTyVarTy mkTypeKind `thenNF_Tc` \ tau -> - unifyTauTy (m tau) exp_ty `thenTc_` + let + -- exp has type (m tau) for some tau (doesn't matter what) + exp_ty = m tau + in + tc_expr exp exp_ty `thenTc` \ (exp', exp_lie) -> returnTc (ExprStmt exp' src_loc, exp_lie, exp_ty) )) `thenTc` \ (stmt', stmt_lie, stmt_ty) -> do_next `thenTc` \ (thing', thing_lie) -> @@ -864,8 +877,7 @@ tcStmt tc_expr do_or_lc m combine stmt@(BindStmt pat exp src_loc) do_next tcAddSrcLoc src_loc ( tcSetErrCtxt (stmtCtxt do_or_lc stmt) ( tcPat pat `thenTc` \ (pat', pat_lie, pat_ty) -> - tc_expr exp `thenTc` \ (exp', exp_lie, exp_ty) -> - unifyTauTy (m pat_ty) exp_ty `thenTc_` + tc_expr exp (m pat_ty) `thenTc` \ (exp', exp_lie) -> -- NB: the environment has been extended with the new binders -- which the rhs can't "see", but the renamer should have made @@ -885,7 +897,7 @@ tcStmt tc_expr do_or_lc m combine (LetStmt binds) do_next binds do_next where - combine' binds' thing' = combine (LetStmt binds') Nothing thing' + combine' is_rec binds' thing' = combine (LetStmt (MonoBind binds' [] is_rec)) Nothing thing' \end{code} %************************************************************************ @@ -943,7 +955,7 @@ tcRecordBinds expected_record_ty rbinds Just (record_ty, field_ty) = getFunTy_maybe tau in unifyTauTy expected_record_ty record_ty `thenTc_` - tcArg field_ty rhs `thenTc` \ (rhs', lie) -> + tcPolyExpr rhs field_ty `thenTc` \ (rhs', lie) -> returnTc ((RealId sel_id, rhs', pun_flag), lie) badFields rbinds data_con @@ -961,13 +973,13 @@ badFields rbinds data_con %************************************************************************ \begin{code} -tcExprs :: [RenamedHsExpr] -> TcM s ([TcExpr s], LIE s, [TcType s]) +tcExprs :: [RenamedHsExpr] -> [TcType s] -> TcM s ([TcExpr s], LIE s) -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) +tcExprs [] [] = returnTc ([], emptyLIE) +tcExprs (expr:exprs) (ty:tys) + = tcExpr expr ty `thenTc` \ (expr', lie1) -> + tcExprs exprs tys `thenTc` \ (exprs', lie2) -> + returnTc (expr':exprs', lie1 `plusLIE` lie2) \end{code} @@ -993,50 +1005,49 @@ branchCtxt b1 b2 sty pp_nest_hang "`else' branch:" (ppr sty b2)] caseCtxt expr sty - = hang (ptext SLIT("In a case expression:")) 4 (ppr sty expr) + = hang (ptext SLIT("In the case expression")) 4 (ppr sty expr) exprSigCtxt expr sty = hang (ptext SLIT("In an expression with a type signature:")) 4 (ppr sty expr) listCtxt expr sty - = hang (ptext SLIT("In a list expression:")) 4 (ppr sty expr) + = hang (ptext SLIT("In the list element")) 4 (ppr sty expr) predCtxt expr sty - = hang (ptext SLIT("In a predicate expression:")) 4 (ppr sty expr) + = hang (ptext SLIT("In the predicate expression")) 4 (ppr sty expr) sectionRAppCtxt expr sty - = hang (ptext SLIT("In a right section:")) 4 (ppr sty expr) + = hang (ptext SLIT("In the right section")) 4 (ppr sty expr) sectionLAppCtxt expr sty - = hang (ptext SLIT("In a left section:")) 4 (ppr sty expr) + = hang (ptext SLIT("In the left section")) 4 (ppr sty expr) -funAppCtxt fun arg_no arg sty - = hang (hsep [ ptext SLIT("In the"), speakNth arg_no, ptext SLIT("argument of"), - ppr sty fun <> text ", namely"]) - 4 (pprParendExpr sty arg) - -stmtCtxt ListComp stmt sty - = hang (ptext SLIT("In a list-comprehension qualifer:")) - 4 (ppr sty stmt) - -stmtCtxt DoStmt stmt sty - = hang (ptext SLIT("In a do statement:")) +stmtCtxt do_or_lc stmt sty + = hang (ptext SLIT("In a") <+> whatever <> colon) 4 (ppr sty stmt) + where + whatever = case do_or_lc of + ListComp -> ptext SLIT("list-comprehension qualifier") + DoStmt -> ptext SLIT("do statement") + Guard -> ptext SLIT("guard") tooManyArgsCtxt f sty = hang (ptext SLIT("Too many arguments in an application of the function")) 4 (ppr sty f) +funAppCtxt fun arg arg_no sty + = hang (hsep [ptext SLIT("In the"), speakNth arg_no, ptext SLIT("argument of"), + ppr sty fun <> text ", namely"]) + 4 (ppr sty arg) + lurkingRank2Err fun fun_ty sty = hang (hsep [ptext SLIT("Illegal use of"), ppr sty fun]) 4 (vcat [text "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 - = hang (ptext SLIT("In a polymorphic function argument:")) - 4 (sep [(<>) (ppr sty arg) (ptext SLIT(" ::")), - ppr sty expected_arg_ty]) + = ptext SLIT("In a polymorphic function argument") <+> ppr sty arg badFieldsUpd rbinds sty = hang (ptext SLIT("No constructor has all these fields:"))