X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=compiler%2Ftypecheck%2FTcInstDcls.lhs;h=177a16f1a2d57a4d43d86364d14f0102eab61458;hb=9b69d74f05582ccf140c007128a52274aa49bd65;hp=e7c472b4751cbf3d863b209687da1596e0256eea;hpb=5e5310b3cb4f78e30cc7b90879eb016e97c214cb;p=ghc-hetmet.git diff --git a/compiler/typecheck/TcInstDcls.lhs b/compiler/typecheck/TcInstDcls.lhs index e7c472b..177a16f 100644 --- a/compiler/typecheck/TcInstDcls.lhs +++ b/compiler/typecheck/TcInstDcls.lhs @@ -21,7 +21,7 @@ import FamInst import FamInstEnv import TcDeriv import TcEnv -import RnEnv ( lookupImportedName ) +import RnEnv ( lookupGlobalOccRn ) import TcHsType import TcUnify import TcSimplify @@ -461,11 +461,11 @@ tcLocalInstDecl1 (L loc (InstDecl poly_ty binds uprags ats)) ; mapM_ (checkIndexes clas inst_tys) ats } - checkIndexes clas inst_tys (hsAT, ATyCon tycon) = + checkIndexes clas inst_tys (hsAT, ATyCon tycon) -- !!!TODO: check that this does the Right Thing for indexed synonyms, too! - checkIndexes' clas inst_tys hsAT - (tyConTyVars tycon, - snd . fromJust . tyConFamInst_maybe $ tycon) + = checkIndexes' clas inst_tys hsAT + (tyConTyVars tycon, + snd . fromJust . tyConFamInst_maybe $ tycon) checkIndexes _ _ _ = panic "checkIndexes" checkIndexes' clas (instTvs, instTys) hsAT (atTvs, atTys) @@ -475,8 +475,8 @@ tcLocalInstDecl1 (L loc (InstDecl poly_ty binds uprags ats)) addErrCtxt (atInstCtxt atName) $ case find ((atName ==) . tyConName) (classATs clas) of Nothing -> addErrTc $ badATErr clas atName -- not in this class - Just atDecl -> - case assocTyConArgPoss_maybe atDecl of + Just atycon -> + case assocTyConArgPoss_maybe atycon of Nothing -> panic "checkIndexes': AT has no args poss?!?" Just poss -> @@ -487,6 +487,13 @@ tcLocalInstDecl1 (L loc (InstDecl poly_ty binds uprags ats)) -- which must be type variables; and (3) variables in AT and -- instance head will be different `Name's even if their -- source lexemes are identical. + -- + -- e.g. class C a b c where + -- data D b a :: * -> * -- NB (1) b a, omits c + -- instance C [x] Bool Char where + -- data D Bool [x] v = MkD x [v] -- NB (2) v + -- -- NB (3) the x in 'instance C...' have differnt + -- -- Names to x's in 'data D...' -- -- Re (1), `poss' contains a permutation vector to extract the -- class parameters in the right order. @@ -557,11 +564,21 @@ tcInstDecls2 tycl_decls inst_decls unionManyBags inst_binds_s ; tcl_env <- getLclEnv -- Default method Ids in here ; return (binds, tcl_env) } + +tcInstDecl2 :: InstInfo Name -> TcM (LHsBinds Id) +tcInstDecl2 (InstInfo { iSpec = ispec, iBinds = ibinds }) + = recoverM (return emptyLHsBinds) $ + setSrcSpan loc $ + addErrCtxt (instDeclCtxt2 (idType dfun_id)) $ + tc_inst_decl2 dfun_id ibinds + where + dfun_id = instanceDFunId ispec + loc = getSrcSpan dfun_id \end{code} \begin{code} -tcInstDecl2 :: InstInfo Name -> TcM (LHsBinds Id) +tc_inst_decl2 :: Id -> InstBindings Name -> TcM (LHsBinds Id) -- Returns a binding for the dfun ------------------------ @@ -583,9 +600,8 @@ tcInstDecl2 :: InstInfo Name -> TcM (LHsBinds Id) -- If there are no superclasses, matters are simpler, because we don't need the case -- see Note [Newtype deriving superclasses] in TcDeriv.lhs -tcInstDecl2 (InstInfo { iSpec = ispec, iBinds = NewTypeDerived }) - = do { let dfun_id = instanceDFunId ispec - rigid_info = InstSkol +tc_inst_decl2 dfun_id (NewTypeDerived coi) + = do { let rigid_info = InstSkol origin = SigOrigin rigid_info inst_ty = idType dfun_id ; (inst_tvs', theta, inst_head_ty) <- tcSkolSigType rigid_info inst_ty @@ -686,103 +702,95 @@ tcInstDecl2 (InstInfo { iSpec = ispec, iBinds = NewTypeDerived }) ------------------------ -- Ordinary instances -tcInstDecl2 (InstInfo { iSpec = ispec, iBinds = VanillaInst monobinds uprags }) - = let - dfun_id = instanceDFunId ispec - rigid_info = InstSkol - inst_ty = idType dfun_id - loc = getSrcSpan dfun_id - in - -- Prime error recovery - recoverM (return emptyLHsBinds) $ - setSrcSpan loc $ - addErrCtxt (instDeclCtxt2 (idType dfun_id)) $ do +tc_inst_decl2 dfun_id (VanillaInst monobinds uprags) + = do { let rigid_info = InstSkol + inst_ty = idType dfun_id -- Instantiate the instance decl with skolem constants - (inst_tyvars', dfun_theta', inst_head') <- tcSkolSigType rigid_info inst_ty + ; (inst_tyvars', dfun_theta', inst_head') <- tcSkolSigType rigid_info inst_ty -- These inst_tyvars' scope over the 'where' part -- Those tyvars are inside the dfun_id's type, which is a bit -- bizarre, but OK so long as you realise it! - let - (clas, inst_tys') = tcSplitDFunHead inst_head' - (class_tyvars, sc_theta, _, op_items) = classBigSig clas + ; let + (clas, inst_tys') = tcSplitDFunHead inst_head' + (class_tyvars, sc_theta, _, op_items) = classBigSig clas - -- Instantiate the super-class context with inst_tys - sc_theta' = substTheta (zipOpenTvSubst class_tyvars inst_tys') sc_theta - origin = SigOrigin rigid_info + -- Instantiate the super-class context with inst_tys + sc_theta' = substTheta (zipOpenTvSubst class_tyvars inst_tys') sc_theta + origin = SigOrigin rigid_info -- Create dictionary Ids from the specified instance contexts. - sc_loc <- getInstLoc InstScOrigin - sc_dicts <- newDictOccs sc_loc sc_theta' -- These are wanted - inst_loc <- getInstLoc origin - dfun_dicts <- newDictBndrs inst_loc dfun_theta' -- Includes equalities - this_dict <- newDictBndr inst_loc (mkClassPred clas inst_tys') + ; sc_loc <- getInstLoc InstScOrigin + ; sc_dicts <- newDictOccs sc_loc sc_theta' -- These are wanted + ; inst_loc <- getInstLoc origin + ; dfun_dicts <- newDictBndrs inst_loc dfun_theta' -- Includes equalities + ; this_dict <- newDictBndr inst_loc (mkClassPred clas inst_tys') -- Default-method Ids may be mentioned in synthesised RHSs, -- but they'll already be in the environment. -- Typecheck the methods - let this_dict_id = instToId this_dict - dfun_lam_vars = map instToVar dfun_dicts -- Includes equalities - prag_fn = mkPragFun uprags - tc_meth = tcInstanceMethod loc clas inst_tyvars' - dfun_dicts - dfun_theta' inst_tys' - this_dict dfun_id - prag_fn monobinds - (meth_exprs, meth_binds) <- tcExtendTyVarEnv inst_tyvars' $ + ; let this_dict_id = instToId this_dict + dfun_lam_vars = map instToVar dfun_dicts -- Includes equalities + prag_fn = mkPragFun uprags + loc = getSrcSpan dfun_id + tc_meth = tcInstanceMethod loc clas inst_tyvars' + dfun_dicts + dfun_theta' inst_tys' + this_dict dfun_id + prag_fn monobinds + ; (meth_exprs, meth_binds) <- tcExtendTyVarEnv inst_tyvars' $ mapAndUnzipM tc_meth op_items - -- Figure out bindings for the superclass context - -- Don't include this_dict in the 'givens', else - -- sc_dicts get bound by just selecting from this_dict!! - sc_binds <- addErrCtxt superClassCtxt $ - tcSimplifySuperClasses inst_loc this_dict dfun_dicts sc_dicts + -- Figure out bindings for the superclass context + -- Don't include this_dict in the 'givens', else + -- sc_dicts get bound by just selecting from this_dict!! + ; sc_binds <- addErrCtxt superClassCtxt $ + tcSimplifySuperClasses inst_loc this_dict dfun_dicts sc_dicts -- Note [Recursive superclasses] -- It's possible that the superclass stuff might unified something -- in the envt with one of the inst_tyvars' - checkSigTyVars inst_tyvars' - - -- Deal with 'SPECIALISE instance' pragmas - prags <- tcPrags dfun_id (filter isSpecInstLSig uprags) - - -- Create the result bindings - let - dict_constr = classDataCon clas - inline_prag | null dfun_dicts = [] - | otherwise = [L loc (InlinePrag (Inline AlwaysActive True))] - -- Always inline the dfun; this is an experimental decision - -- because it makes a big performance difference sometimes. - -- Often it means we can do the method selection, and then - -- inline the method as well. Marcin's idea; see comments below. - -- - -- BUT: don't inline it if it's a constant dictionary; - -- we'll get all the benefit without inlining, and we get - -- a **lot** of code duplication if we inline it - -- - -- See Note [Inline dfuns] below - - sc_dict_vars = map instToVar sc_dicts - dict_bind = L loc (VarBind this_dict_id dict_rhs) - dict_rhs = foldl (\ f a -> L loc (HsApp f (L loc a))) inst_constr meth_exprs - inst_constr = L loc $ wrapId (mkWpApps sc_dict_vars <.> mkWpTyApps inst_tys') - (dataConWrapId dict_constr) - -- We don't produce a binding for the dict_constr; instead we - -- rely on the simplifier to unfold this saturated application - -- We do this rather than generate an HsCon directly, because - -- it means that the special cases (e.g. dictionary with only one - -- member) are dealt with by the common MkId.mkDataConWrapId code rather - -- than needing to be repeated here. - - - main_bind = noLoc $ AbsBinds - inst_tyvars' - dfun_lam_vars - [(inst_tyvars', dfun_id, this_dict_id, inline_prag ++ prags)] - (dict_bind `consBag` sc_binds) - - showLIE (text "instance") - return (main_bind `consBag` unionManyBags meth_binds) + ; checkSigTyVars inst_tyvars' + + -- Deal with 'SPECIALISE instance' pragmas + ; prags <- tcPrags dfun_id (filter isSpecInstLSig uprags) + + -- Create the result bindings + ; let dict_constr = classDataCon clas + inline_prag | null dfun_dicts = [] + | otherwise = [L loc (InlinePrag (Inline AlwaysActive True))] + -- Always inline the dfun; this is an experimental decision + -- because it makes a big performance difference sometimes. + -- Often it means we can do the method selection, and then + -- inline the method as well. Marcin's idea; see comments below. + -- + -- BUT: don't inline it if it's a constant dictionary; + -- we'll get all the benefit without inlining, and we get + -- a **lot** of code duplication if we inline it + -- + -- See Note [Inline dfuns] below + + sc_dict_vars = map instToVar sc_dicts + dict_bind = L loc (VarBind this_dict_id dict_rhs) + dict_rhs = foldl (\ f a -> L loc (HsApp f (L loc a))) inst_constr meth_exprs + inst_constr = L loc $ wrapId (mkWpApps sc_dict_vars <.> mkWpTyApps inst_tys') + (dataConWrapId dict_constr) + -- We don't produce a binding for the dict_constr; instead we + -- rely on the simplifier to unfold this saturated application + -- We do this rather than generate an HsCon directly, because + -- it means that the special cases (e.g. dictionary with only one + -- member) are dealt with by the common MkId.mkDataConWrapId code rather + -- than needing to be repeated here. + + + main_bind = noLoc $ AbsBinds + inst_tyvars' + dfun_lam_vars + [(inst_tyvars', dfun_id, this_dict_id, inline_prag ++ prags)] + (dict_bind `consBag` sc_binds) + + ; showLIE (text "instance") + ; return (main_bind `consBag` unionManyBags meth_binds) } \end{code} Note [Recursive superclasses] @@ -863,7 +871,7 @@ tcInstanceMethod loc clas tyvars dfun_dicts theta inst_tys { -- Build the typechecked version directly, -- without calling typecheck_method; -- see Note [Default methods in instances] - dm_name <- lookupImportedName (mkDefMethRdrName sel_name) + dm_name <- lookupGlobalOccRn (mkDefMethRdrName sel_name) -- Might not be imported, but will be an OrigName ; dm_id <- tcLookupId dm_name ; return (wrapId dm_wrapper dm_id, emptyBag) } } @@ -963,7 +971,7 @@ mustBeVarArgErr ty = wrongATArgErr :: Type -> Type -> SDoc wrongATArgErr ty instTy = sep [ ptext (sLit "Type indexes must match class instance head") - , ptext (sLit "Found") <+> ppr ty <+> ptext (sLit "but expected") <+> - ppr instTy + , ptext (sLit "Found") <+> quotes (ppr ty) + <+> ptext (sLit "but expected") <+> quotes (ppr instTy) ] \end{code}