X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Fcompiler%2Ftypecheck%2FTcBinds.lhs;h=35f3923352eb88f46a70dc4b4fe7c909e6c4c2d0;hb=525aeb93903b0bc968915f3df4f7df755e24e8c7;hp=6c0ec0305b84c20b7794c6db546f7f701b465473;hpb=9e93335020e64a811dbbb223e1727c76933a93ae;p=ghc-hetmet.git diff --git a/ghc/compiler/typecheck/TcBinds.lhs b/ghc/compiler/typecheck/TcBinds.lhs index 6c0ec03..35f3923 100644 --- a/ghc/compiler/typecheck/TcBinds.lhs +++ b/ghc/compiler/typecheck/TcBinds.lhs @@ -15,7 +15,8 @@ import {-# SOURCE #-} TcExpr ( tcExpr ) import CmdLineOpts ( opt_NoMonomorphismRestriction ) import HsSyn ( HsExpr(..), HsBinds(..), MonoBinds(..), Sig(..), Match(..), HsMatchContext(..), - collectMonoBinders, andMonoBinds + collectMonoBinders, andMonoBinds, + collectSigTysFromMonoBinds ) import RnHsSyn ( RenamedHsBinds, RenamedSig, RenamedMonoBinds ) import TcHsSyn ( TcMonoBinds, TcId, zonkId, mkHsLet ) @@ -24,18 +25,16 @@ import TcMonad import Inst ( LIE, emptyLIE, mkLIE, plusLIE, InstOrigin(..), newDicts, instToId ) -import TcEnv ( tcExtendLocalValEnv, - newSpecPragmaId, newLocalId - ) +import TcEnv ( tcExtendLocalValEnv, newLocalName ) +import TcUnify ( unifyTauTyLists, checkSigTyVars, sigCtxt ) import TcSimplify ( tcSimplifyInfer, tcSimplifyInferCheck, tcSimplifyRestricted, tcSimplifyToDicts ) -import TcMonoType ( tcHsSigType, UserTypeCtxt(..), checkSigTyVars, - TcSigInfo(..), tcTySig, maybeSig, sigCtxt +import TcMonoType ( tcHsSigType, UserTypeCtxt(..), + TcSigInfo(..), tcTySig, maybeSig, tcAddScopedTyVars ) -import TcPat ( tcPat ) +import TcPat ( tcPat, tcSubPat, tcMonoPatBndr ) import TcSimplify ( bindInstsOfLocalFuns ) -import TcMType ( newTyVarTy, newTyVar, - zonkTcTyVarToTyVar, - unifyTauTy, unifyTauTyLists +import TcMType ( newTyVar, newTyVarTy, newHoleTyVarTy, + zonkTcTyVarToTyVar ) import TcType ( mkTyVarTy, mkForAllTys, mkFunTys, tyVarsOfType, mkPredTy, mkForAllTy, isUnLiftedType, @@ -43,9 +42,9 @@ import TcType ( mkTyVarTy, mkForAllTys, mkFunTys, tyVarsOfType, ) import CoreFVs ( idFreeTyVars ) -import Id ( mkLocalId, setInlinePragma ) +import Id ( mkLocalId, mkSpecPragmaId, setInlinePragma ) import Var ( idType, idName ) -import Name ( Name, getOccName, getSrcLoc ) +import Name ( Name, getSrcLoc ) import NameSet import Var ( tyVarKind ) import VarSet @@ -118,7 +117,14 @@ tc_binds_and_then top_lvl combiner (ThenBinds b1 b2) do_next do_next tc_binds_and_then top_lvl combiner (MonoBind bind sigs is_rec) do_next - = -- TYPECHECK THE SIGNATURES + = -- BRING ANY SCOPED TYPE VARIABLES INTO SCOPE + -- Notice that they scope over + -- a) the type signatures in the binding group + -- b) the bindings in the group + -- c) the scope of the binding group (the "in" part) + tcAddScopedTyVars (collectSigTysFromMonoBinds bind) $ + + -- TYPECHECK THE SIGNATURES mapTc tcTySig [sig | sig@(Sig name _ _) <- sigs] `thenTc` \ tc_ty_sigs -> tcBindWithSigs top_lvl bind tc_ty_sigs @@ -249,12 +255,10 @@ tcBindWithSigs top_lvl mbind tc_ty_sigs inline_sigs is_rec mapNF_Tc zonkId dict_ids `thenNF_Tc` \ zonked_dict_ids -> mapNF_Tc zonkId mono_ids `thenNF_Tc` \ zonked_mono_ids -> - -- CHECK FOR BOGUS UNLIFTED BINDINGS - checkUnliftedBinds top_lvl is_rec real_tyvars_to_gen mbind zonked_mono_ids `thenTc_` - -- BUILD THE POLYMORPHIC RESULT IDs let exports = zipWith mk_export binder_names zonked_mono_ids + poly_ids = [poly_id | (_, poly_id, _) <- exports] dict_tys = map idType zonked_dict_ids inlines = mkNameSet [name | InlineSig True name _ loc <- inline_sigs] @@ -275,8 +279,8 @@ tcBindWithSigs top_lvl mbind tc_ty_sigs inline_sigs is_rec new_poly_id = mkLocalId binder_name poly_ty poly_ty = mkForAllTys real_tyvars_to_gen - $ mkFunTys dict_tys - $ idType zonked_mono_id + $ mkFunTys dict_tys + $ idType zonked_mono_id -- It's important to build a fully-zonked poly_ty, because -- we'll slurp out its free type variables when extending the -- local environment (tcExtendLocalValEnv); if it's not zonked @@ -285,17 +289,28 @@ tcBindWithSigs top_lvl mbind tc_ty_sigs inline_sigs is_rec in traceTc (text "binding:" <+> ppr ((zonked_dict_ids, dict_binds), - exports, [idType poly_id | (_, poly_id, _) <- exports])) `thenTc_` + exports, map idType poly_ids)) `thenTc_` + + -- Check for an unlifted, non-overloaded group + -- In that case we must make extra checks + if any (isUnLiftedType . idType) zonked_mono_ids && null zonked_dict_ids + then -- Some bindings are unlifted + checkUnliftedBinds top_lvl is_rec real_tyvars_to_gen mbind `thenTc_` + + returnTc ( + AbsBinds [] [] exports inlines mbind', + lie_req, -- Do not generate even any x=y bindings + poly_ids + ) - -- BUILD RESULTS + else -- The normal case returnTc ( AbsBinds real_tyvars_to_gen zonked_dict_ids exports inlines (dict_binds `andMonoBinds` mbind'), - lie_free, - [poly_id | (_, poly_id, _) <- exports] + lie_free, poly_ids ) attachNoInlinePrag no_inlines bndr @@ -303,7 +318,13 @@ attachNoInlinePrag no_inlines bndr Just prag -> bndr `setInlinePragma` prag Nothing -> bndr -checkUnliftedBinds top_lvl is_rec real_tyvars_to_gen mbind zonked_mono_ids +-- Check that non-overloaded unlifted bindings are +-- a) non-recursive, +-- b) not top level, +-- c) non-polymorphic +-- d) not a multiple-binding group (more or less implied by (a)) + +checkUnliftedBinds top_lvl is_rec real_tyvars_to_gen mbind = ASSERT( not (any ((eqKind unliftedTypeKind) . tyVarKind) real_tyvars_to_gen) ) -- The instCantBeGeneralised stuff in tcSimplify should have -- already raised an error if we're trying to generalise an @@ -312,34 +333,19 @@ checkUnliftedBinds top_lvl is_rec real_tyvars_to_gen mbind zonked_mono_ids -- because we have more precise origin information. -- That's why we just use an ASSERT here. - -- Check that pattern-bound variables are not unlifted - (if or [ (idName id `elem` pat_binders) && isUnLiftedType (idType id) - | id <- zonked_mono_ids ] then - addErrTc (unliftedBindErr "Pattern" mbind) - else - returnTc () - ) `thenTc_` - - -- Unlifted bindings must be non-recursive, - -- not top level, non-polymorphic, and not pattern bound - if any (isUnLiftedType . idType) zonked_mono_ids then - checkTc (isNotTopLevel top_lvl) - (unliftedBindErr "Top-level" mbind) `thenTc_` - checkTc (isNonRec is_rec) - (unliftedBindErr "Recursive" mbind) `thenTc_` - checkTc (null real_tyvars_to_gen) - (unliftedBindErr "Polymorphic" mbind) - else - returnTc () + checkTc (isNotTopLevel top_lvl) + (unliftedBindErr "Top-level" mbind) `thenTc_` + checkTc (isNonRec is_rec) + (unliftedBindErr "Recursive" mbind) `thenTc_` + checkTc (single_bind mbind) + (unliftedBindErr "Multiple" mbind) `thenTc_` + checkTc (null real_tyvars_to_gen) + (unliftedBindErr "Polymorphic" mbind) where - pat_binders :: [Name] - pat_binders = collectMonoBinders (justPatBindings mbind EmptyMonoBinds) - - justPatBindings bind@(PatMonoBind _ _ _) binds = bind `andMonoBinds` binds - justPatBindings (AndMonoBinds b1 b2) binds = - justPatBindings b1 (justPatBindings b2 binds) - justPatBindings other_bind binds = binds + single_bind (PatMonoBind _ _ _) = True + single_bind (FunMonoBind _ _ _ _) = True + single_bind other = False \end{code} @@ -481,11 +487,11 @@ checkSigsCtxts sigs@(TySigInfo _ id1 sig_tvs theta1 _ _ _ src_loc : other_sigs) checkSigsTyVars sigs = mapTc_ check_one sigs where check_one (TySigInfo _ id sig_tyvars sig_theta sig_tau _ _ src_loc) - = tcAddSrcLoc src_loc $ - tcAddErrCtxtM (sigCtxt (sig_msg id) sig_tyvars sig_theta sig_tau) $ + = tcAddSrcLoc src_loc $ + tcAddErrCtxt (ptext SLIT("When checking the type signature for") + <+> quotes (ppr id)) $ + tcAddErrCtxtM (sigCtxt sig_tyvars sig_theta sig_tau) $ checkSigTyVars sig_tyvars (idFreeTyVars id) - - sig_msg id = ptext SLIT("When checking the type signature for") <+> quotes (ppr id) \end{code} @getTyVarsToGen@ decides what type variables to generalise over. @@ -536,14 +542,14 @@ is_elem v vs = isIn "isUnResMono" v vs isUnRestrictedGroup sigs (PatMonoBind other _ _) = False isUnRestrictedGroup sigs (VarMonoBind v _) = v `is_elem` sigs -isUnRestrictedGroup sigs (FunMonoBind v _ matches _) = any isUnRestrictedMatch matches || +isUnRestrictedGroup sigs (FunMonoBind v _ matches _) = isUnRestrictedMatch matches || v `is_elem` sigs isUnRestrictedGroup sigs (AndMonoBinds mb1 mb2) = isUnRestrictedGroup sigs mb1 && isUnRestrictedGroup sigs mb2 isUnRestrictedGroup sigs EmptyMonoBinds = True -isUnRestrictedMatch (Match _ [] Nothing _) = False -- No args, no signature -isUnRestrictedMatch other = True -- Some args or a signature +isUnRestrictedMatch (Match [] _ _ : _) = False -- No args => like a pattern binding +isUnRestrictedMatch other = True -- Some args => a function binding \end{code} @@ -601,23 +607,6 @@ tcMonoBinds mbinds tc_ty_sigs is_rec returnTc (mbinds', lie_req_pat `plusLIE` lie_req_rhss, names, mono_ids) where - -- This function is used when dealing with a LHS binder; - -- we make a monomorphic version of the Id. - -- We check for a type signature; if there is one, we use the mono_id - -- from the signature. This is how we make sure the tau part of the - -- signature actually maatches the type of the LHS; then tc_mb_pats - -- ensures the LHS and RHS have the same type - - tc_pat_bndr name pat_ty - = case maybeSig tc_ty_sigs name of - Nothing - -> newLocalId (getOccName name) pat_ty (getSrcLoc name) - - Just (TySigInfo _ _ _ _ _ mono_id _ _) - -> tcAddSrcLoc (getSrcLoc name) $ - unifyTauTy (idType mono_id) pat_ty `thenTc_` - returnTc mono_id - mk_bind (name, mono_id) = case maybeSig tc_ty_sigs name of Nothing -> (name, mono_id) Just (TySigInfo name poly_id _ _ _ _ _ _) -> (name, poly_id) @@ -640,9 +629,18 @@ tcMonoBinds mbinds tc_ty_sigs is_rec lie_avail1 `plusLIE` lie_avail2) tc_mb_pats (FunMonoBind name inf matches locn) - = newTyVarTy kind `thenNF_Tc` \ bndr_ty -> - tc_pat_bndr name bndr_ty `thenTc` \ bndr_id -> + = (case maybeSig tc_ty_sigs name of + Just (TySigInfo _ _ _ _ _ mono_id _ _) + -> returnNF_Tc mono_id + Nothing -> newLocalName name `thenNF_Tc` \ bndr_name -> + newTyVarTy openTypeKind `thenNF_Tc` \ bndr_ty -> + -- NB: not a 'hole' tyvar; since there is no type + -- signature, we revert to ordinary H-M typechecking + -- which means the variable gets an inferred tau-type + returnNF_Tc (mkLocalId bndr_name bndr_ty) + ) `thenNF_Tc` \ bndr_id -> let + bndr_ty = idType bndr_id complete_it xve = tcAddSrcLoc locn $ tcMatchesFun xve name bndr_ty matches `thenTc` \ (matches', lie) -> returnTc (FunMonoBind bndr_id inf matches' locn, lie) @@ -651,19 +649,16 @@ tcMonoBinds mbinds tc_ty_sigs is_rec tc_mb_pats bind@(PatMonoBind pat grhss locn) = tcAddSrcLoc locn $ - newTyVarTy kind `thenNF_Tc` \ pat_ty -> + newHoleTyVarTy `thenNF_Tc` \ pat_ty -> -- Now typecheck the pattern - -- We don't support binding fresh (not-already-in-scope) scoped + -- We do now support binding fresh (not-already-in-scope) scoped -- type variables in the pattern of a pattern binding. - -- For example, this is illegal: + -- For example, this is now legal: -- (x::a, y::b) = e - -- whereas this is ok - -- (x::Int, y::Bool) = e - -- - -- We don't check explicitly for this problem. Instead, we simply - -- type check the pattern with tcPat. If the pattern mentions any - -- fresh tyvars we simply get an out-of-scope type variable error + -- The type variables are brought into scope in tc_binds_and_then, + -- so we don't have to do anything here. + tcPat tc_pat_bndr pat pat_ty `thenTc` \ (pat', lie_req, tvs, ids, lie_avail) -> let complete_it xve = tcAddSrcLoc locn $ @@ -674,11 +669,24 @@ tcMonoBinds mbinds tc_ty_sigs is_rec in returnTc (complete_it, lie_req, tvs, ids, lie_avail) - -- Figure out the appropriate kind for the pattern, - -- and generate a suitable type variable - kind = case is_rec of - Recursive -> liftedTypeKind -- Recursive, so no unlifted types - NonRecursive -> openTypeKind -- Non-recursive, so we permit unlifted types + -- tc_pat_bndr is used when dealing with a LHS binder in a pattern. + -- If there was a type sig for that Id, we want to make it much + -- as if that type signature had been on the binder as a SigPatIn. + -- We check for a type signature; if there is one, we use the mono_id + -- from the signature. This is how we make sure the tau part of the + -- signature actually matches the type of the LHS; then tc_mb_pats + -- ensures the LHS and RHS have the same type + + tc_pat_bndr name pat_ty + = case maybeSig tc_ty_sigs name of + Nothing + -> newLocalName name `thenNF_Tc` \ bndr_name -> + tcMonoPatBndr bndr_name pat_ty + + Just (TySigInfo _ _ _ _ _ mono_id _ _) + -> tcAddSrcLoc (getSrcLoc name) $ + tcSubPat pat_ty (idType mono_id) `thenTc` \ (co_fn, lie) -> + returnTc (co_fn, lie, mono_id) \end{code} @@ -743,11 +751,15 @@ tcSpecSigs (SpecSig name poly_ty src_loc : sigs) -- Just specialise "f" by building a SpecPragmaId binding -- It is the thing that makes sure we don't prematurely -- dead-code-eliminate the binding we are really interested in. - newSpecPragmaId name sig_ty `thenNF_Tc` \ spec_id -> + newLocalName name `thenNF_Tc` \ spec_name -> + let + spec_bind = VarMonoBind (mkSpecPragmaId spec_name sig_ty) + (mkHsLet spec_binds spec_expr) + in -- Do the rest and combine tcSpecSigs sigs `thenTc` \ (binds_rest, lie_rest) -> - returnTc (binds_rest `andMonoBinds` VarMonoBind spec_id (mkHsLet spec_binds spec_expr), + returnTc (binds_rest `andMonoBinds` spec_bind, lie_rest `plusLIE` mkLIE spec_dicts) tcSpecSigs (other_sig : sigs) = tcSpecSigs sigs @@ -802,5 +814,7 @@ genCtxt binder_names = ptext SLIT("When generalising the type(s) for") <+> pprBinders binder_names -- Used in error messages -pprBinders bndrs = pprWithCommas ppr bndrs +-- Use quotes for a single one; they look a bit "busy" for several +pprBinders [bndr] = quotes (ppr bndr) +pprBinders bndrs = pprWithCommas ppr bndrs \end{code}