X-Git-Url: http://git.megacz.com/?p=ghc-hetmet.git;a=blobdiff_plain;f=compiler%2Ftypecheck%2FTcInstDcls.lhs;h=954471f8c3955816c5cb6ce79eb715850f9b1ccc;hp=16ae6410f298ae8e92961ec697285a887e089311;hb=febf1ced754a3996ac1a5877dcded87828560d1c;hpb=a3bab0506498db41853543558c52a4fda0d183af diff --git a/compiler/typecheck/TcInstDcls.lhs b/compiler/typecheck/TcInstDcls.lhs index 16ae641..954471f 100644 --- a/compiler/typecheck/TcInstDcls.lhs +++ b/compiler/typecheck/TcInstDcls.lhs @@ -13,26 +13,27 @@ import TcBinds import TcTyClsDecls import TcClassDcl import TcPat( addInlinePrags ) -import TcSimplify( simplifyTop ) import TcRnMonad import TcMType import TcType +import BuildTyCl import Inst import InstEnv import FamInst import FamInstEnv -import MkCore ( nO_METHOD_BINDING_ERROR_ID ) import TcDeriv import TcEnv import RnSource ( addTcgDUs ) import TcHsType import TcUnify +import MkCore ( nO_METHOD_BINDING_ERROR_ID ) import Type import Coercion import TyCon import DataCon import Class import Var +import Pair import VarSet import CoreUtils ( mkPiTypes ) import CoreUnfold ( mkDFunUnfolding ) @@ -183,13 +184,14 @@ Instead we use a cunning trick. Note [Single-method classes] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~ If the class has just one method (or, more accurately, just one element -of {superclasses + methods}), then we still use the *same* strategy +of {superclasses + methods}), then we use a different strategy. class C a where op :: a -> a instance C a => C [a] where op = -We translate the class decl into a newtype, which just gives -a top-level axiom: +We translate the class decl into a newtype, which just gives a +top-level axiom. The "constructor" MkC expands to a cast, as does the +class-op selector. axiom Co:C a :: C a ~ (a->a) @@ -199,44 +201,82 @@ a top-level axiom: MkC :: forall a. (a->a) -> C a MkC = /\a.\op. op |> (sym Co:C a) - df :: forall a. C a => C [a] - {-# NOINLINE df DFun[ $cop_list ] #-} - df = /\a. \d. MkC ($cop_list a d) +The clever RULE stuff doesn't work now, because ($df a d) isn't +a constructor application, so exprIsConApp_maybe won't return +Just . - $cop_list :: forall a. C a => [a] -> [a] - $cop_list = +Instead, we simply rely on the fact that casts are cheap: -The "constructor" MkC expands to a cast, as does the class-op selector. -The RULE works just like for multi-field dictionaries: + $df :: forall a. C a => C [a] + {-# INLINE df #} -- NB: INLINE this + $df = /\a. \d. MkC [a] ($cop_list a d) + = $cop_list |> forall a. C a -> (sym (Co:C [a])) - * (df a d) returns (Just (MkC,..,[$cop_list a d])) - to exprIsConApp_Maybe + $cop_list :: forall a. C a => [a] -> [a] + $cop_list = - * The RULE for op picks the right result +So if we see + (op ($df a d)) +we'll inline 'op' and '$df', since both are simply casts, and +good things happen. -This is a bit of a hack, because (df a d) isn't *really* a constructor -application. But it works just fine in this case, exprIsConApp_maybe -is otherwise used only when we hit a case expression which will have -a real data constructor in it. +Why do we use this different strategy? Because otherwise we +end up with non-inlined dictionaries that look like + $df = $cop |> blah +which adds an extra indirection to every use, which seems stupid. See +Trac #4138 for an example (although the regression reported there +wasn't due to the indirction). -The biggest reason for doing it this way, apart from uniformity, is -that we want to be very careful when we have +There is an awkward wrinkle though: we want to be very +careful when we have instance C a => C [a] where {-# INLINE op #-} op = ... then we'll get an INLINE pragma on $cop_list but it's important that $cop_list only inlines when it's applied to *two* arguments (the -dictionary and the list argument +dictionary and the list argument). So we nust not eta-expand $df +above. We ensure that this doesn't happen by putting an INLINE +pragma on the dfun itself; after all, it ends up being just a cast. + +There is one more dark corner to the INLINE story, even more deeply +buried. Consider this (Trac #3772): + + class DeepSeq a => C a where + gen :: Int -> a + + instance C a => C [a] where + gen n = ... + + class DeepSeq a where + deepSeq :: a -> b -> b + + instance DeepSeq a => DeepSeq [a] where + {-# INLINE deepSeq #-} + deepSeq xs b = foldr deepSeq b xs + +That gives rise to these defns: + + $cdeepSeq :: DeepSeq a -> [a] -> b -> b + -- User INLINE( 3 args )! + $cdeepSeq a (d:DS a) b (x:[a]) (y:b) = ... + + $fDeepSeq[] :: DeepSeq a -> DeepSeq [a] + -- DFun (with auto INLINE pragma) + $fDeepSeq[] a d = $cdeepSeq a d |> blah + + $cp1 a d :: C a => DeepSep [a] + -- We don't want to eta-expand this, lest + -- $cdeepSeq gets inlined in it! + $cp1 a d = $fDeepSep[] a (scsel a d) -The danger is that we'll get something like - op_list :: C a => [a] -> [a] - op_list = /\a.\d. $cop_list a d -and then we'll eta expand, and then we'll inline TOO EARLY. This happened in -Trac #3772 and I spent far too long fiddling around trying to fix it. -Look at the test for Trac #3772. + $fC[] :: C a => C [a] + -- Ordinary DFun + $fC[] a d = MkC ($cp1 a d) ($cgen a d) - (Note: re-reading the above, I can't see how using the - uniform story solves the problem.) +Here $cp1 is the code that generates the superclass for C [a]. The +issue is this: we must not eta-expand $cp1 either, or else $fDeepSeq[] +and then $cdeepSeq will inline there, which is definitely wrong. Like +on the dfun, we solve this by adding an INLINE pragma to $cp1. Note [Subtle interaction of recursion and overlap] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ @@ -332,7 +372,7 @@ tcInstDecls1 tycl_decls inst_decls deriv_decls ; let { (local_info, at_tycons_s) = unzip local_info_tycons ; at_idx_tycons = concat at_tycons_s ++ idx_tycons - ; clas_decls = filter (isClassDecl.unLoc) tycl_decls + ; clas_decls = filter (isClassDecl . unLoc) tycl_decls ; implicit_things = concatMap implicitTyThings at_idx_tycons ; aux_binds = mkRecSelBinds at_idx_tycons } @@ -511,8 +551,8 @@ tcLocalInstDecl1 (L loc (InstDecl poly_ty binds uprags ats)) | isTyVarTy ty = return () | otherwise = addErrTc $ mustBeVarArgErr ty checkIndex ty (Just instTy) - | ty `tcEqType` instTy = return () - | otherwise = addErrTc $ wrongATArgErr ty instTy + | ty `eqType` instTy = return () + | otherwise = addErrTc $ wrongATArgErr ty instTy listToNameSet = addListToNameSet emptyNameSet @@ -525,7 +565,183 @@ tcLocalInstDecl1 (L loc (InstDecl poly_ty binds uprags ats)) tv1 `sameLexeme` tv2 = nameOccName (tyVarName tv1) == nameOccName (tyVarName tv2) in - extendTvSubst (substSameTyVar tvs replacingTvs) tv replacement + TcType.extendTvSubst (substSameTyVar tvs replacingTvs) tv replacement +\end{code} + + +%************************************************************************ +%* * + Type checking family instances +%* * +%************************************************************************ + +Family instances are somewhat of a hybrid. They are processed together with +class instance heads, but can contain data constructors and hence they share a +lot of kinding and type checking code with ordinary algebraic data types (and +GADTs). + +\begin{code} +tcFamInstDecl :: TopLevelFlag -> LTyClDecl Name -> TcM TyThing +tcFamInstDecl top_lvl (L loc decl) + = -- Prime error recovery, set source location + setSrcSpan loc $ + tcAddDeclCtxt decl $ + do { -- type family instances require -XTypeFamilies + -- and can't (currently) be in an hs-boot file + ; type_families <- xoptM Opt_TypeFamilies + ; is_boot <- tcIsHsBoot -- Are we compiling an hs-boot file? + ; checkTc type_families $ badFamInstDecl (tcdLName decl) + ; checkTc (not is_boot) $ badBootFamInstDeclErr + + -- Perform kind and type checking + ; tc <- tcFamInstDecl1 decl + ; checkValidTyCon tc -- Remember to check validity; + -- no recursion to worry about here + + -- Check that toplevel type instances are not for associated types. + ; when (isTopLevel top_lvl && isAssocFamily tc) + (addErr $ assocInClassErr (tcdName decl)) + + ; return (ATyCon tc) } + +isAssocFamily :: TyCon -> Bool -- Is an assocaited type +isAssocFamily tycon + = case tyConFamInst_maybe tycon of + Nothing -> panic "isAssocFamily: no family?!?" + Just (fam, _) -> isTyConAssoc fam + +assocInClassErr :: Name -> SDoc +assocInClassErr name + = ptext (sLit "Associated type") <+> quotes (ppr name) <+> + ptext (sLit "must be inside a class instance") + + + +tcFamInstDecl1 :: TyClDecl Name -> TcM TyCon + + -- "type instance" +tcFamInstDecl1 (decl@TySynonym {tcdLName = L loc tc_name}) + = kcIdxTyPats decl $ \k_tvs k_typats resKind family -> + do { -- check that the family declaration is for a synonym + checkTc (isFamilyTyCon family) (notFamily family) + ; checkTc (isSynTyCon family) (wrongKindOfFamily family) + + ; -- (1) kind check the right-hand side of the type equation + ; k_rhs <- kcCheckLHsType (tcdSynRhs decl) (EK resKind EkUnk) + -- ToDo: the ExpKind could be better + + -- we need the exact same number of type parameters as the family + -- declaration + ; let famArity = tyConArity family + ; checkTc (length k_typats == famArity) $ + wrongNumberOfParmsErr famArity + + -- (2) type check type equation + ; tcTyVarBndrs k_tvs $ \t_tvs -> do { -- turn kinded into proper tyvars + ; t_typats <- mapM tcHsKindedType k_typats + ; t_rhs <- tcHsKindedType k_rhs + + -- (3) check the well-formedness of the instance + ; checkValidTypeInst t_typats t_rhs + + -- (4) construct representation tycon + ; rep_tc_name <- newFamInstTyConName tc_name t_typats loc + ; buildSynTyCon rep_tc_name t_tvs (SynonymTyCon t_rhs) + (typeKind t_rhs) + NoParentTyCon (Just (family, t_typats)) + }} + + -- "newtype instance" and "data instance" +tcFamInstDecl1 (decl@TyData {tcdND = new_or_data, tcdLName = L loc tc_name, + tcdCons = cons}) + = kcIdxTyPats decl $ \k_tvs k_typats resKind fam_tycon -> + do { -- check that the family declaration is for the right kind + checkTc (isFamilyTyCon fam_tycon) (notFamily fam_tycon) + ; checkTc (isAlgTyCon fam_tycon) (wrongKindOfFamily fam_tycon) + + ; -- (1) kind check the data declaration as usual + ; k_decl <- kcDataDecl decl k_tvs + ; let k_ctxt = tcdCtxt k_decl + k_cons = tcdCons k_decl + + -- result kind must be '*' (otherwise, we have too few patterns) + ; checkTc (isLiftedTypeKind resKind) $ tooFewParmsErr (tyConArity fam_tycon) + + -- (2) type check indexed data type declaration + ; tcTyVarBndrs k_tvs $ \t_tvs -> do { -- turn kinded into proper tyvars + ; unbox_strict <- doptM Opt_UnboxStrictFields + + -- kind check the type indexes and the context + ; t_typats <- mapM tcHsKindedType k_typats + ; stupid_theta <- tcHsKindedContext k_ctxt + + -- (3) Check that + -- (a) left-hand side contains no type family applications + -- (vanilla synonyms are fine, though, and we checked for + -- foralls earlier) + ; mapM_ checkTyFamFreeness t_typats + + ; dataDeclChecks tc_name new_or_data stupid_theta k_cons + + -- (4) construct representation tycon + ; rep_tc_name <- newFamInstTyConName tc_name t_typats loc + ; let ex_ok = True -- Existentials ok for type families! + ; fixM (\ rep_tycon -> do + { let orig_res_ty = mkTyConApp fam_tycon t_typats + ; data_cons <- tcConDecls unbox_strict ex_ok rep_tycon + (t_tvs, orig_res_ty) k_cons + ; tc_rhs <- + case new_or_data of + DataType -> return (mkDataTyConRhs data_cons) + NewType -> ASSERT( not (null data_cons) ) + mkNewTyConRhs rep_tc_name rep_tycon (head data_cons) + ; buildAlgTyCon rep_tc_name t_tvs stupid_theta tc_rhs Recursive + False h98_syntax NoParentTyCon (Just (fam_tycon, t_typats)) + -- We always assume that indexed types are recursive. Why? + -- (1) Due to their open nature, we can never be sure that a + -- further instance might not introduce a new recursive + -- dependency. (2) They are always valid loop breakers as + -- they involve a coercion. + }) + }} + where + h98_syntax = case cons of -- All constructors have same shape + L _ (ConDecl { con_res = ResTyGADT _ }) : _ -> False + _ -> True + +tcFamInstDecl1 d = pprPanic "tcFamInstDecl1" (ppr d) + +-- Kind checking of indexed types +-- - + +-- Kind check type patterns and kind annotate the embedded type variables. +-- +-- * Here we check that a type instance matches its kind signature, but we do +-- not check whether there is a pattern for each type index; the latter +-- check is only required for type synonym instances. + +kcIdxTyPats :: TyClDecl Name + -> ([LHsTyVarBndr Name] -> [LHsType Name] -> Kind -> TyCon -> TcM a) + -- ^^kinded tvs ^^kinded ty pats ^^res kind + -> TcM a +kcIdxTyPats decl thing_inside + = kcHsTyVars (tcdTyVars decl) $ \tvs -> + do { let tc_name = tcdLName decl + ; fam_tycon <- tcLookupLocatedTyCon tc_name + ; let { (kinds, resKind) = splitKindFunTys (tyConKind fam_tycon) + ; hs_typats = fromJust $ tcdTyPats decl } + + -- we may not have more parameters than the kind indicates + ; checkTc (length kinds >= length hs_typats) $ + tooManyParmsErr (tcdLName decl) + + -- type functions can have a higher-kinded result + ; let resultKind = mkArrowKinds (drop (length hs_typats) kinds) resKind + ; typats <- zipWithM kcCheckLHsType hs_typats + [ EK kind (EkArg (ppr tc_name) n) + | (kind,n) <- kinds `zip` [1..]] + ; thing_inside tvs typats resultKind fam_tycon + } \end{code} @@ -582,7 +798,10 @@ tcInstDecl2 (InstInfo { iSpec = ispec, iBinds = ibinds }) setSrcSpan loc $ addErrCtxt (instDeclCtxt2 (idType dfun_id)) $ do { -- Instantiate the instance decl with skolem constants - ; (inst_tyvars, dfun_theta, inst_head) <- tcSkolSigType skol_info (idType dfun_id) + ; (inst_tyvars, dfun_theta, inst_head) <- tcSkolDFunType (idType dfun_id) + -- We instantiate the dfun_id with superSkolems. + -- See Note [Subtle interaction of recursion and overlap] + -- and Note [Binding when looking up instances] ; let (clas, inst_tys) = tcSplitDFunHead inst_head (class_tyvars, sc_theta, _, op_items) = classBigSig clas sc_theta' = substTheta (zipOpenTvSubst class_tyvars inst_tys) sc_theta @@ -594,20 +813,19 @@ tcInstDecl2 (InstInfo { iSpec = ispec, iBinds = ibinds }) ; orig_ev_vars <- newEvVars orig_theta ; let dfun_ev_vars = silent_ev_vars ++ orig_ev_vars - ; (sc_binds, sc_dicts, sc_args) - <- mapAndUnzip3M (tcSuperClass n_ty_args dfun_ev_vars) sc_theta' + ; (sc_dicts, sc_args) + <- mapAndUnzipM (tcSuperClass n_ty_args dfun_ev_vars) sc_theta' -- Check that any superclasses gotten from a silent arguemnt -- can be deduced from the originally-specified dfun arguments ; ct_loc <- getCtLoc ScOrigin ; _ <- checkConstraints skol_info inst_tyvars orig_ev_vars $ - emitConstraints $ listToBag $ - [ WcEvVar (WantedEvVar sc ct_loc) - | sc <- sc_dicts, isSilentEvVar sc ] + emitFlats $ listToBag $ + [ mkEvVarX sc ct_loc | sc <- sc_dicts, isSilentEvVar sc ] -- Deal with 'SPECIALISE instance' pragmas -- See Note [SPECIALISE instance pragmas] - ; spec_info <- tcSpecInstPrags dfun_id ibinds + ; spec_info@(spec_inst_prags,_) <- tcSpecInstPrags dfun_id ibinds -- Typecheck the methods ; (meth_ids, meth_binds) @@ -621,18 +839,19 @@ tcInstDecl2 (InstInfo { iSpec = ispec, iBinds = ibinds }) -- Create the result bindings ; self_dict <- newEvVar (ClassP clas inst_tys) - ; let dict_constr = classDataCon clas - dict_bind = mkVarBind self_dict dict_rhs - dict_rhs = foldl mk_app inst_constr $ - map HsVar sc_dicts ++ map (wrapId arg_wrapper) meth_ids - inst_constr = L loc $ wrapId (mkWpTyApps inst_tys) - (dataConWrapId dict_constr) + ; let class_tc = classTyCon clas + [dict_constr] = tyConDataCons class_tc + dict_bind = mkVarBind self_dict dict_rhs + dict_rhs = foldl mk_app inst_constr $ + map HsVar sc_dicts ++ map (wrapId arg_wrapper) meth_ids + inst_constr = L loc $ wrapId (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. + -- member) are dealt with by the common MkId.mkDataConWrapId + -- code rather than needing to be repeated here. mk_app :: LHsExpr Id -> HsExpr Id -> LHsExpr Id mk_app fun arg = L loc (HsApp fun (L loc arg)) @@ -642,50 +861,46 @@ tcInstDecl2 (InstInfo { iSpec = ispec, iBinds = ibinds }) -- Do not inline the dfun; instead give it a magic DFunFunfolding -- See Note [ClassOp/DFun selection] -- See also note [Single-method classes] - dfun_id_w_fun = dfun_id - `setIdUnfolding` mkDFunUnfolding dfun_ty (sc_args ++ meth_args) - `setInlinePragma` dfunInlinePragma + dfun_id_w_fun + | isNewTyCon class_tc + = dfun_id `setInlinePragma` alwaysInlinePragma { inl_sat = Just 0 } + | otherwise + = dfun_id `setIdUnfolding` mkDFunUnfolding dfun_ty (sc_args ++ meth_args) + `setInlinePragma` dfunInlinePragma meth_args = map (DFunPolyArg . Var) meth_ids main_bind = AbsBinds { abs_tvs = inst_tyvars , abs_ev_vars = dfun_ev_vars , abs_exports = [(inst_tyvars, dfun_id_w_fun, self_dict, - SpecPrags [] {- spec_inst_prags -})] + SpecPrags spec_inst_prags)] , abs_ev_binds = emptyTcEvBinds , abs_binds = unitBag dict_bind } ; return (unitBag (L loc main_bind) `unionBags` - unionManyBags sc_binds `unionBags` listToBag meth_binds) } where - skol_info = InstSkol -- See Note [Subtle interaction of recursion and overlap] + skol_info = InstSkol dfun_ty = idType dfun_id dfun_id = instanceDFunId ispec loc = getSrcSpan dfun_id ------------------------------ -tcSuperClass :: Int -> [EvVar] -> PredType -> TcM (LHsBinds Id, Id, DFunArg CoreExpr) +tcSuperClass :: Int -> [EvVar] -> PredType -> TcM (EvVar, DFunArg CoreExpr) +-- All superclasses should be either +-- (a) be one of the arguments to the dfun, of +-- (b) be a constant, soluble at top level tcSuperClass n_ty_args ev_vars pred | Just (ev, i) <- find n_ty_args ev_vars - = return (emptyBag, ev, DFunLamArg i) + = return (ev, DFunLamArg i) | otherwise - = ASSERT2( isEmptyVarSet (tyVarsOfPred pred), ppr pred) - do { sc_dict <- newWantedEvVar pred - ; loc <- getCtLoc ScOrigin - ; ev_binds <- simplifyTop (unitBag (WcEvVar (WantedEvVar sc_dict loc))) - ; let ev_wrap = WpLet (EvBinds ev_binds) - sc_bind = mkVarBind sc_dict (noLoc $ (wrapId ev_wrap sc_dict)) - ; return (unitBag sc_bind, sc_dict, DFunConstArg (Var sc_dict)) } - -- It's very important to solve the superclass constraint *in isolation* - -- so that it isn't generated by superclass selection from something else - -- We then generate the (also rather degenerate) top-level binding: - -- sc_dict = let sc_dict = in sc_dict - -- where is generated by solving the implication constraint + = ASSERT2( isEmptyVarSet (tyVarsOfPred pred), ppr pred) -- Constant! + do { sc_dict <- emitWanted ScOrigin pred + ; return (sc_dict, DFunConstArg (Var sc_dict)) } where find _ [] = Nothing - find i (ev:evs) | pred `tcEqPred` evVarPred ev = Just (ev, i) - | otherwise = find (i+1) evs + find i (ev:evs) | pred `eqPred` evVarPred ev = Just (ev, i) + | otherwise = find (i+1) evs ------------------------------ tcSpecInstPrags :: DFunId -> InstBindings Name @@ -820,7 +1035,7 @@ tcSpecInst dfun_id prag@(SpecInstSig hs_ty) ; (tyvars, theta, clas, tys) <- tcHsInstHead hs_ty ; let (_, spec_dfun_ty) = mkDictFunTy tyvars theta clas tys - ; co_fn <- tcSubType (SpecPragOrigin name) (SigSkol SpecInstCtxt) + ; co_fn <- tcSubType (SpecPragOrigin name) SpecInstCtxt (idType dfun_id) spec_dfun_ty ; return (SpecPrag dfun_id co_fn defaultInlinePragma) } where @@ -1008,13 +1223,12 @@ tcInstanceMethods dfun_id clas tyvars dfun_ev_vars inst_tys inst_tvs = fst (tcSplitForAllTys (idType dfun_id)) Just (init_inst_tys, _) = snocView inst_tys - rep_ty = fst (coercionKind co) -- [p] + rep_ty = pFst (coercionKind co) -- [p] rep_pred = mkClassPred clas (init_inst_tys ++ [rep_ty]) -- co : [p] ~ T p - co = substTyWith inst_tvs (mkTyVarTys tyvars) $ - case coi of { IdCo ty -> ty ; - ACo co -> mkSymCoercion co } + co = substCoWithTys inst_tvs (mkTyVarTys tyvars) $ + mkSymCo coi ---------------- tc_item :: (TcEvBinds, EvVar) -> (Id, DefMeth) -> TcM (TcId, LHsBind TcId) @@ -1038,7 +1252,8 @@ tcInstanceMethods dfun_id clas tyvars dfun_ev_vars inst_tys ---------------- mk_op_wrapper :: Id -> EvVar -> HsWrapper mk_op_wrapper sel_id rep_d - = WpCast (substTyWith sel_tvs (init_inst_tys ++ [co]) local_meth_ty) + = WpCast (liftCoSubstWith sel_tvs (map mkReflCo init_inst_tys ++ [co]) + local_meth_ty) <.> WpEvApp (EvId rep_d) <.> mkWpTyApps (init_inst_tys ++ [rep_ty]) where @@ -1206,7 +1421,7 @@ instDeclCtxt2 :: Type -> SDoc instDeclCtxt2 dfun_ty = inst_decl_ctxt (ppr (mkClassPred cls tys)) where - (_,cls,tys) = tcSplitDFunTy dfun_ty + (_,_,cls,tys) = tcSplitDFunTy dfun_ty inst_decl_ctxt :: SDoc -> SDoc inst_decl_ctxt doc = ptext (sLit "In the instance declaration for") <+> quotes doc @@ -1228,4 +1443,37 @@ wrongATArgErr ty instTy = , ptext (sLit "Found") <+> quotes (ppr ty) <+> ptext (sLit "but expected") <+> quotes (ppr instTy) ] + +tooManyParmsErr :: Located Name -> SDoc +tooManyParmsErr tc_name + = ptext (sLit "Family instance has too many parameters:") <+> + quotes (ppr tc_name) + +tooFewParmsErr :: Arity -> SDoc +tooFewParmsErr arity + = ptext (sLit "Family instance has too few parameters; expected") <+> + ppr arity + +wrongNumberOfParmsErr :: Arity -> SDoc +wrongNumberOfParmsErr exp_arity + = ptext (sLit "Number of parameters must match family declaration; expected") + <+> ppr exp_arity + +badBootFamInstDeclErr :: SDoc +badBootFamInstDeclErr + = ptext (sLit "Illegal family instance in hs-boot file") + +notFamily :: TyCon -> SDoc +notFamily tycon + = vcat [ ptext (sLit "Illegal family instance for") <+> quotes (ppr tycon) + , nest 2 $ parens (ppr tycon <+> ptext (sLit "is not an indexed type family"))] + +wrongKindOfFamily :: TyCon -> SDoc +wrongKindOfFamily family + = ptext (sLit "Wrong category of family instance; declaration was for a") + <+> kindOfFamily + where + kindOfFamily | isSynTyCon family = ptext (sLit "type synonym") + | isAlgTyCon family = ptext (sLit "data type") + | otherwise = pprPanic "wrongKindOfFamily" (ppr family) \end{code}