X-Git-Url: http://git.megacz.com/?p=ghc-hetmet.git;a=blobdiff_plain;f=compiler%2Ftypecheck%2FTcClassDcl.lhs;h=4f1f32c0f9f8176ba5d889f1e2a520506cbbd291;hp=c3edcc4ca752ceeb97eb4296ab0082cecc8b1eff;hb=9d0c8f842e35dde3d570580cf62a32779f66a6de;hpb=f16dbbbe59cf3aa19c5fd384560a1b89076d7bc8 diff --git a/compiler/typecheck/TcClassDcl.lhs b/compiler/typecheck/TcClassDcl.lhs index c3edcc4..4f1f32c 100644 --- a/compiler/typecheck/TcClassDcl.lhs +++ b/compiler/typecheck/TcClassDcl.lhs @@ -7,7 +7,7 @@ Typechecking class declarations \begin{code} module TcClassDcl ( tcClassSigs, tcClassDecl2, - findMethodBind, tcMethodBind, + findMethodBind, tcInstanceMethodBody, mkGenericDefMethBind, getGenericInstances, mkDefMethRdrName, tcAddDeclCtxt, badMethodErr, badATErr, omittedATWarn ) where @@ -22,6 +22,7 @@ import Inst import InstEnv import TcEnv import TcBinds +import TcSimplify import TcHsType import TcMType import TcType @@ -167,8 +168,8 @@ tcClassDecl2 :: LTyClDecl Name -- The class declaration tcClassDecl2 (L loc (ClassDecl {tcdLName = class_name, tcdSigs = sigs, tcdMeths = default_binds})) = recoverM (return (emptyLHsBinds, [])) $ - setSrcSpan loc $ do - clas <- tcLookupLocatedClass class_name + setSrcSpan loc $ + do { clas <- tcLookupLocatedClass class_name -- We make a separate binding for each default method. -- At one time I used a single AbsBinds for all of them, thus @@ -178,59 +179,59 @@ tcClassDecl2 (L loc (ClassDecl {tcdLName = class_name, tcdSigs = sigs, -- dm1 = \d -> case ds d of (a,b,c) -> a -- And since ds is big, it doesn't get inlined, so we don't get good -- default methods. Better to make separate AbsBinds for each - let - (tyvars, _, _, op_items) = classBigSig clas - rigid_info = ClsSkol clas - prag_fn = mkPragFun sigs - sig_fn = mkTcSigFun sigs - clas_tyvars = tcSkolSigTyVars rigid_info tyvars - tc_dm = tcDefMeth clas_tyvars default_binds - sig_fn prag_fn - -- tc_dm is called only for a sel_id - -- that has a binding in default_binds - - dm_sel_ids = [sel_id | (sel_id, DefMeth) <- op_items] - -- Generate code for polymorphic default methods only - -- (Generic default methods have turned into instance decls by now.) - -- This is incompatible with Hugs, which expects a polymorphic - -- default method for every class op, regardless of whether or not - -- the programmer supplied an explicit default decl for the class. - -- (If necessary we can fix that, but we don't have a convenient Id to hand.) - - (defm_binds, dm_ids) <- mapAndUnzipM tc_dm dm_sel_ids - return (unionManyBags defm_binds, dm_ids) + ; let + (tyvars, _, _, op_items) = classBigSig clas + rigid_info = ClsSkol clas + prag_fn = mkPragFun sigs + sig_fn = mkTcSigFun sigs + clas_tyvars = tcSkolSigTyVars rigid_info tyvars + pred = mkClassPred clas (mkTyVarTys clas_tyvars) + ; inst_loc <- getInstLoc (SigOrigin rigid_info) + ; this_dict <- newDictBndr inst_loc pred + + ; let tc_dm = tcDefMeth rigid_info clas clas_tyvars [pred] + this_dict default_binds + sig_fn prag_fn + -- tc_dm is called only for a sel_id + -- that has a binding in default_binds + + dm_sel_ids = [sel_id | (sel_id, DefMeth) <- op_items] + -- Generate code for polymorphic default methods only (hence DefMeth) + -- (Generic default methods have turned into instance decls by now.) + -- This is incompatible with Hugs, which expects a polymorphic + -- default method for every class op, regardless of whether or not + -- the programmer supplied an explicit default decl for the class. + -- (If necessary we can fix that, but we don't have a convenient Id to hand.) + + ; (defm_binds, dm_ids) <- tcExtendTyVarEnv clas_tyvars $ + mapAndUnzipM tc_dm dm_sel_ids + + ; return (unionManyBags defm_binds, dm_ids) } + tcClassDecl2 d = pprPanic "tcClassDecl2" (ppr d) -tcDefMeth :: [TyVar] -> LHsBinds Name +tcDefMeth :: SkolemInfo -> Class -> [TyVar] -> ThetaType -> Inst -> LHsBinds Name -> TcSigFun -> TcPragFun -> Id -> TcM (LHsBinds Id, Id) -tcDefMeth tyvars binds_in sig_fn prag_fn sel_id +tcDefMeth rigid_info clas tyvars theta this_dict binds_in sig_fn prag_fn sel_id = do { let sel_name = idName sel_id - ; dm_name <- lookupTopBndrRn (mkDefMethRdrName sel_name) - ; uniq <- newUnique - ; let dm_ty = idType sel_id -- Same as dict selector! - local_dm_name = setNameUnique sel_name uniq - local_dm_id = mkLocalId local_dm_name dm_ty - top_dm_id = mkDefaultMethodId dm_name dm_ty - all_tvs = map tyVarName tyvars ++ (sig_fn sel_name `orElse` []) - -- Tyvars in scope are *both* the ones from the - -- class decl *and* ones from the method sig - + ; local_dm_name <- newLocalName sel_name ; let meth_bind = findMethodBind sel_name local_dm_name binds_in `orElse` pprPanic "tcDefMeth" (ppr sel_id) -- We only call tcDefMeth on selectors for which -- there is a binding in binds_in - ; tc_meth_bind <- tcMethodBind all_tvs (prag_fn sel_name) - local_dm_id meth_bind + meth_sig_fn _ = sig_fn sel_name + meth_prag_fn _ = prag_fn sel_name - -- See Note [Silly default-method bind] - ; let loc = getLoc meth_bind - top_bind = L loc $ VarBind top_dm_id $ - L loc $ HsWrap (WpLet tc_meth_bind) $ - HsVar local_dm_id + ; (top_dm_id, bind) <- tcInstanceMethodBody rigid_info + clas tyvars [this_dict] theta (mkTyVarTys tyvars) + Nothing sel_id + local_dm_name + meth_sig_fn meth_prag_fn + meth_bind - ; return (unitBag top_bind, top_dm_id) } + ; return (bind, top_dm_id) } mkDefMethRdrName :: Name -> RdrName mkDefMethRdrName sel_name = mkDerivedRdrName sel_name mkDefaultMethodOcc @@ -249,29 +250,64 @@ findMethodBind sel_name meth_name binds = Just (L loc1 (bind { fun_id = L loc2 meth_name })) f _other = Nothing ---------------------------- -tcMethodBind :: [Name] -> [LSig Name] -> Id - -> LHsBind Name -> TcM (LHsBinds Id) -tcMethodBind tyvars prags meth_id bind - = do { let sig_fn _ = Just tyvars - prag_fn _ = prags +--------------- +tcInstanceMethodBody :: SkolemInfo -> Class -> [TcTyVar] -> [Inst] + -> TcThetaType -> [TcType] + -> Maybe (Inst, LHsBind Id) -> Id + -> Name -- The local method name + -> TcSigFun -> TcPragFun -> LHsBind Name + -> TcM (Id, LHsBinds Id) +tcInstanceMethodBody rigid_info clas tyvars dfun_dicts theta inst_tys + mb_this_bind sel_id local_meth_name + sig_fn prag_fn bind@(L loc _) + = do { let (sel_tyvars,sel_rho) = tcSplitForAllTys (idType sel_id) + rho_ty = ASSERT( length sel_tyvars == length inst_tys ) + substTyWith sel_tyvars inst_tys sel_rho + + (first_pred, local_meth_ty) = tcSplitPredFunTy_maybe rho_ty + `orElse` pprPanic "tcInstanceMethod" (ppr sel_id) + + local_meth_id = mkLocalId local_meth_name local_meth_ty + meth_ty = mkSigmaTy tyvars theta local_meth_ty + sel_name = idName sel_id + + -- The first predicate should be of form (C a b) + -- where C is the class in question + ; MASSERT( case getClassPredTys_maybe first_pred of + { Just (clas1, _tys) -> clas == clas1 ; Nothing -> False } ) -- Typecheck the binding, first extending the envt - -- so that when tcInstSig looks up the meth_id to find - -- its signature, we'll find it in the environment - -- - -- If scoped type variables is on, they are brought - -- into scope by tcPolyBinds (via sig_fn) - -- - -- See Note [Polymorphic methods] - ; traceTc (text "tcMethodBind" <+> ppr meth_id <+> ppr tyvars) - ; (tc_binds, ids) <- tcExtendIdEnv [meth_id] $ - tcPolyBinds TopLevel sig_fn prag_fn - NonRecursive NonRecursive - (unitBag bind) - - ; ASSERT( ids == [meth_id] ) -- Binding for ONE method - return (unionManyBags tc_binds) } + -- so that when tcInstSig looks up the local_meth_id to find + -- its signature, we'll find it in the environment + ; ((tc_bind, _), lie) <- getLIE $ + tcExtendIdEnv [local_meth_id] $ + tcPolyBinds TopLevel sig_fn prag_fn + NonRecursive NonRecursive + (unitBag bind) + + ; meth_id <- case rigid_info of + ClsSkol _ -> do { dm_name <- lookupTopBndrRn (mkDefMethRdrName sel_name) + ; return (mkDefaultMethodId dm_name meth_ty) } + _other -> do { meth_name <- newLocalName sel_name + ; return (mkLocalId meth_name meth_ty) } + + ; let (avails, this_dict_bind) + = case mb_this_bind of + Nothing -> (dfun_dicts, emptyBag) + Just (this, bind) -> (this : dfun_dicts, unitBag bind) + + ; inst_loc <- getInstLoc (SigOrigin rigid_info) + ; lie_binds <- tcSimplifyCheck inst_loc tyvars avails lie + + ; let full_bind = L loc $ + AbsBinds tyvars dfun_lam_vars + [(tyvars, meth_id, local_meth_id, [])] + (this_dict_bind `unionBags` lie_binds + `unionBags` tc_bind) + + dfun_lam_vars = map instToVar dfun_dicts -- Includes equalities + + ; return (meth_id, unitBag full_bind) } \end{code} Note [Polymorphic methods] @@ -294,8 +330,9 @@ Note [Silly default-method bind] When we pass the default method binding to the type checker, it must look like op2 = e not $dmop2 = e -otherwise the "$dm" stuff comes out in the interface file. So we -typecheck the former, and wrap it in a let, thus +otherwise the "$dm" stuff comes out error messages. But we want the +"$dm" to come out in the interface file. So we typecheck the former, +and wrap it in a let, thus $dmop2 = let op2 = e in op2 This makes the error messages right. @@ -415,7 +452,7 @@ get_generics decl@(ClassDecl {tcdLName = class_name, tcdMeths = def_methods}) group `lengthExceeds` 1] get_uniq (tc,_) = getUnique tc - mapM (addErrTc . dupGenericInsts) bad_groups + mapM_ (addErrTc . dupGenericInsts) bad_groups -- Check that there is an InstInfo for each generic type constructor let