X-Git-Url: http://git.megacz.com/?p=ghc-hetmet.git;a=blobdiff_plain;f=compiler%2Frename%2FRnEnv.lhs;h=c3b5592834f2ac5855cc1707fd281fa5b65ea0b7;hp=94c90ac90bcf46afbfb592b862f752d8a135532d;hb=f1cc3eb980a634e62f2739a7a25387c902fa9d8a;hpb=432b38b66700d243369df5b76e5c5c01b5e197ff diff --git a/compiler/rename/RnEnv.lhs b/compiler/rename/RnEnv.lhs index 94c90ac..c3b5592 100644 --- a/compiler/rename/RnEnv.lhs +++ b/compiler/rename/RnEnv.lhs @@ -1,4 +1,4 @@ -\% +% % (c) The GRASP/AQUA Project, Glasgow University, 1992-2006 % \section[RnEnv]{Environment manipulation for the renamer monad} @@ -6,31 +6,31 @@ \begin{code} module RnEnv ( newTopSrcBinder, lookupFamInstDeclBndr, - lookupLocatedBndrRn, lookupBndrRn, lookupBndrRn_maybe, lookupLocatedTopBndrRn, lookupTopBndrRn, lookupLocatedOccRn, lookupOccRn, - lookupLocatedGlobalOccRn, lookupGlobalOccRn, - lookupLocalDataTcNames, lookupSrcOcc_maybe, + lookupLocatedGlobalOccRn, + lookupGlobalOccRn, lookupGlobalOccRn_maybe, + lookupLocalDataTcNames, lookupSigOccRn, lookupFixityRn, lookupTyFixityRn, - lookupInstDeclBndr, lookupRecordBndr, lookupConstructorFields, - lookupSyntaxName, lookupSyntaxTable, lookupImportedName, + lookupInstDeclBndr, lookupSubBndr, lookupConstructorFields, + lookupSyntaxName, lookupSyntaxTable, lookupGreRn, lookupGreLocalRn, lookupGreRn_maybe, - getLookupOccRn, + getLookupOccRn, addUsedRdrNames, - newLocalsRn, newIPNameRn, - bindLocalNames, bindLocalNamesFV, + newLocalBndrRn, newLocalBndrsRn, newIPNameRn, + bindLocalName, bindLocalNames, bindLocalNamesFV, MiniFixityEnv, emptyFsEnv, extendFsEnv, lookupFsEnv, bindLocalNamesFV_WithFixities, bindLocatedLocalsFV, bindLocatedLocalsRn, bindSigTyVarsFV, bindPatSigTyVars, bindPatSigTyVarsFV, bindTyVarsRn, extendTyVarEnvFVRn, - checkDupRdrNames, checkDupNames, checkShadowedNames, - checkDupAndShadowedRdrNames, - mapFvRn, mapFvRnCPS, + checkDupRdrNames, checkDupAndShadowedRdrNames, + checkDupNames, checkDupAndShadowedNames, + addFvRn, mapFvRn, mapMaybeFvRn, mapFvRnCPS, warnUnusedMatches, warnUnusedModules, warnUnusedImports, warnUnusedTopBinds, warnUnusedLocalBinds, - dataTcOccs, unknownNameErr + dataTcOccs, unknownNameErr, kindSigErr, perhapsForallMsg ) where #include "HsVersions.h" @@ -41,8 +41,9 @@ import HsSyn import RdrHsSyn ( extractHsTyRdrTyVars ) import RdrName import HscTypes ( availNames, ModIface(..), FixItem(..), lookupFixity) -import TcEnv ( tcLookupDataCon ) +import TcEnv ( tcLookupDataCon, tcLookupField, isBrackStage ) import TcRnMonad +import Id ( isRecordSelector ) import Name ( Name, nameIsLocalOrFrom, mkInternalName, isWiredInName, nameSrcLoc, nameSrcSpan, nameOccName, nameModule, isExternalName ) import NameSet @@ -52,39 +53,26 @@ import DataCon ( dataConFieldLabels ) import OccName import Module ( Module, ModuleName ) import PrelNames ( mkUnboundName, rOOT_MAIN, iNTERACTIVE, - consDataConKey, hasKey, forall_tv_RDR ) -import UniqSupply -import BasicTypes ( IPName, mapIPName, Fixity ) + consDataConKey, forall_tv_RDR ) +import Unique +import BasicTypes +import ErrUtils ( Message ) import SrcLoc import Outputable import Util import Maybes import ListSetOps ( removeDups ) -import List ( nubBy ) import DynFlags import FastString import Control.Monad +import Data.List +import qualified Data.Set as Set \end{code} \begin{code} -- XXX thenM :: Monad a => a b -> (b -> a c) -> a c thenM = (>>=) - -thenM_ :: Monad a => a b -> a c -> a c -thenM_ = (>>) - -returnM :: Monad m => a -> m a -returnM = return - -mappM :: (Monad m) => (a -> m b) -> [a] -> m [b] -mappM = mapM - -mappM_ :: (Monad m) => (a -> m b) -> [a] -> m () -mappM_ = mapM_ - -checkM :: Monad m => Bool -> m () -> m () -checkM = unless \end{code} %********************************************************* @@ -107,13 +95,13 @@ newTopSrcBinder this_mod (L loc rdr_name) -- data T = (,) Int Int -- unless we are in GHC.Tup ASSERT2( isExternalName name, ppr name ) - do { checkM (this_mod == nameModule name) + do { unless (this_mod == nameModule name) (addErrAt loc (badOrigBinding rdr_name)) ; return name } | Just (rdr_mod, rdr_occ) <- isOrig_maybe rdr_name - = do { checkM (rdr_mod == this_mod || rdr_mod == rOOT_MAIN) + = do { unless (rdr_mod == this_mod || rdr_mod == rOOT_MAIN) (addErrAt loc (badOrigBinding rdr_name)) -- When reading External Core we get Orig names as binders, -- but they should agree with the module gotten from the monad @@ -136,11 +124,20 @@ newTopSrcBinder this_mod (L loc rdr_name) --TODO, should pass the whole span | otherwise - = do { checkM (not (isQual rdr_name)) + = do { unless (not (isQual rdr_name)) (addErrAt loc (badQualBndrErr rdr_name)) -- Binders should not be qualified; if they are, and with a different -- module name, we we get a confusing "M.T is not in scope" error later - ; newGlobalBinder this_mod (rdrNameOcc rdr_name) loc } + + ; stage <- getStage + ; if isBrackStage stage then + -- We are inside a TH bracket, so make an *Internal* name + -- See Note [Top-level Names in Template Haskell decl quotes] in RnNames + do { uniq <- newUnique + ; return (mkInternalName uniq (rdrNameOcc rdr_name) loc) } + else + -- Normal case + newGlobalBinder this_mod (rdrNameOcc rdr_name) loc } \end{code} %********************************************************* @@ -151,17 +148,19 @@ newTopSrcBinder this_mod (L loc rdr_name) Looking up a name in the RnEnv. -\begin{code} -lookupLocatedBndrRn :: Located RdrName -> RnM (Located Name) -lookupLocatedBndrRn = wrapLocM lookupBndrRn - -lookupBndrRn :: RdrName -> RnM Name -lookupBndrRn n = do nopt <- lookupBndrRn_maybe n - case nopt of - Just n' -> return n' - Nothing -> do traceRn $ text "lookupTopBndrRn" - unboundName n +Note [Type and class operator definitions] +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +We want to reject all of these unless we have -XTypeOperators (Trac #3265) + data a :*: b = ... + class a :*: b where ... + data (:*:) a b = .... + class (:*:) a b where ... +The latter two mean that we are not just looking for a +*syntactically-infix* declaration, but one that uses an operator +OccName. We use OccName.isSymOcc to detect that case, which isn't +terribly efficient, but there seems to be no better way. +\begin{code} lookupTopBndrRn :: RdrName -> RnM Name lookupTopBndrRn n = do nopt <- lookupTopBndrRn_maybe n case nopt of @@ -169,14 +168,6 @@ lookupTopBndrRn n = do nopt <- lookupTopBndrRn_maybe n Nothing -> do traceRn $ text "lookupTopBndrRn" unboundName n -lookupBndrRn_maybe :: RdrName -> RnM (Maybe Name) --- NOTE: assumes that the SrcSpan of the binder has already been setSrcSpan'd -lookupBndrRn_maybe rdr_name - = getLocalRdrEnv `thenM` \ local_env -> - case lookupLocalRdrEnv local_env rdr_name of - Just name -> returnM (Just name) - Nothing -> lookupTopBndrRn_maybe rdr_name - lookupLocatedTopBndrRn :: Located RdrName -> RnM (Located Name) lookupLocatedTopBndrRn = wrapLocM lookupTopBndrRn @@ -199,7 +190,7 @@ lookupTopBndrRn_maybe :: RdrName -> RnM (Maybe Name) lookupTopBndrRn_maybe rdr_name | Just name <- isExact_maybe rdr_name - = returnM (Just name) + = return (Just name) | Just (rdr_mod, rdr_occ) <- isOrig_maybe rdr_name -- This deals with the case of derived bindings, where @@ -210,14 +201,21 @@ lookupTopBndrRn_maybe rdr_name ; return (Just n)} | otherwise - = do { mb_gre <- lookupGreLocalRn rdr_name + = do { -- Check for operators in type or class declarations + -- See Note [Type and class operator definitions] + let occ = rdrNameOcc rdr_name + ; when (isTcOcc occ && isSymOcc occ) + (do { op_ok <- doptM Opt_TypeOperators + ; unless op_ok (addErr (opDeclErr rdr_name)) }) + + ; mb_gre <- lookupGreLocalRn rdr_name ; case mb_gre of - Nothing -> returnM Nothing - Just gre -> returnM (Just $ gre_name gre) } + Nothing -> return Nothing + Just gre -> return (Just $ gre_name gre) } ----------------------------------------------- -lookupInstDeclBndr :: Name -> Located RdrName -> RnM (Located Name) +lookupInstDeclBndr :: Name -> RdrName -> RnM Name -- This is called on the method name on the left-hand side of an -- instance declaration binding. eg. instance Functor T where -- fmap = ... @@ -229,33 +227,17 @@ lookupInstDeclBndr :: Name -> Located RdrName -> RnM (Located Name) -- name is only in scope qualified. I.e. even if method op is -- in scope as M.op, we still allow plain 'op' on the LHS of -- an instance decl -lookupInstDeclBndr cls rdr = lookup_located_sub_bndr is_op doc rdr +lookupInstDeclBndr cls rdr + = do { when (isQual rdr) + (addErr (badQualBndrErr rdr)) + -- In an instance decl you aren't allowed + -- to use a qualified name for the method + -- (Although it'd make perfect sense.) + ; lookupSubBndr (ParentIs cls) doc rdr } where doc = ptext (sLit "method of class") <+> quotes (ppr cls) - is_op (GRE {gre_par = ParentIs n}) = n == cls - is_op _ = False ----------------------------------------------- -lookupRecordBndr :: Maybe (Located Name) -> Located RdrName -> RnM (Located Name) --- Used for record construction and pattern matching --- When the -fdisambiguate-record-fields flag is on, take account of the --- constructor name to disambiguate which field to use; it's just the --- same as for instance decls -lookupRecordBndr Nothing rdr_name - = lookupLocatedGlobalOccRn rdr_name -lookupRecordBndr (Just (L _ data_con)) rdr_name - = do { flag_on <- doptM Opt_DisambiguateRecordFields - ; if not flag_on - then lookupLocatedGlobalOccRn rdr_name - else do { - fields <- lookupConstructorFields data_con - ; let is_field gre = gre_name gre `elem` fields - ; lookup_located_sub_bndr is_field doc rdr_name - }} - where - doc = ptext (sLit "field of constructor") <+> quotes (ppr data_con) - - lookupConstructorFields :: Name -> RnM [Name] -- Look up the fields of a given constructor -- * For constructors from this module, use the record field env, @@ -269,66 +251,103 @@ lookupConstructorFields :: Name -> RnM [Name] lookupConstructorFields con_name = do { this_mod <- getModule ; if nameIsLocalOrFrom this_mod con_name then - do { field_env <- getRecFieldEnv + do { RecFields field_env _ <- getRecFieldEnv ; return (lookupNameEnv field_env con_name `orElse` []) } else do { con <- tcLookupDataCon con_name ; return (dataConFieldLabels con) } } ----------------------------------------------- -lookup_located_sub_bndr :: (GlobalRdrElt -> Bool) - -> SDoc -> Located RdrName - -> RnM (Located Name) -lookup_located_sub_bndr is_good doc rdr_name - = wrapLocM (lookup_sub_bndr is_good doc) rdr_name - -lookup_sub_bndr :: (GlobalRdrElt -> Bool) -> SDoc -> RdrName -> RnM Name -lookup_sub_bndr is_good doc rdr_name - | isUnqual rdr_name -- Find all the things the rdr-name maps to - = do { -- and pick the one with the right parent name +-- Used for record construction and pattern matching +-- When the -XDisambiguateRecordFields flag is on, take account of the +-- constructor name to disambiguate which field to use; it's just the +-- same as for instance decls +-- +-- NB: Consider this: +-- module Foo where { data R = R { fld :: Int } } +-- module Odd where { import Foo; fld x = x { fld = 3 } } +-- Arguably this should work, because the reference to 'fld' is +-- unambiguous because there is only one field id 'fld' in scope. +-- But currently it's rejected. + +lookupSubBndr :: Parent -- NoParent => just look it up as usual + -- ParentIs p => use p to disambiguate + -> SDoc -> RdrName + -> RnM Name +lookupSubBndr parent doc rdr_name + | Just n <- isExact_maybe rdr_name -- This happens in derived code + = return n + + | Just (rdr_mod, rdr_occ) <- isOrig_maybe rdr_name + = lookupOrig rdr_mod rdr_occ + + | otherwise -- Find all the things the rdr-name maps to + = do { -- and pick the one with the right parent name ; env <- getGlobalRdrEnv - ; case filter is_good (lookupGlobalRdrEnv env (rdrNameOcc rdr_name)) of + ; let gres = lookupGlobalRdrEnv env (rdrNameOcc rdr_name) + ; case pick parent gres of -- NB: lookupGlobalRdrEnv, not lookupGRE_RdrName! -- The latter does pickGREs, but we want to allow 'x' -- even if only 'M.x' is in scope - [gre] -> return (gre_name gre) + [gre] -> do { addUsedRdrNames (used_rdr_names gre) + ; return (gre_name gre) } [] -> do { addErr (unknownSubordinateErr doc rdr_name) - ; traceRn (text "RnEnv.lookup_sub_bndr" <+> ppr rdr_name) + ; traceRn (text "RnEnv.lookup_sub_bndr" <+> (ppr rdr_name $$ ppr gres)) ; return (mkUnboundName rdr_name) } gres -> do { addNameClashErrRn rdr_name gres - ; return (gre_name (head gres)) } - } - - | otherwise -- Occurs in derived instances, where we just - -- refer directly to the right method - = ASSERT2( not (isQual rdr_name), ppr rdr_name ) - -- NB: qualified names are rejected by the parser - lookupImportedName rdr_name + ; return (gre_name (head gres)) } } + where + pick NoParent gres -- Normal lookup + = pickGREs rdr_name gres + pick (ParentIs p) gres -- Disambiguating lookup + | isUnqual rdr_name = filter (right_parent p) gres + | otherwise = filter (right_parent p) (pickGREs rdr_name gres) + + right_parent p (GRE { gre_par = ParentIs p' }) = p==p' + right_parent _ _ = False + + -- Note [Usage for sub-bndrs] + used_rdr_names gre + | isQual rdr_name = [rdr_name] + | otherwise = case gre_prov gre of + LocalDef -> [rdr_name] + Imported is -> map mk_qual_rdr is + mk_qual_rdr imp_spec = mkRdrQual (is_as (is_decl imp_spec)) rdr_occ + rdr_occ = rdrNameOcc rdr_name newIPNameRn :: IPName RdrName -> TcRnIf m n (IPName Name) newIPNameRn ip_rdr = newIPName (mapIPName rdrNameOcc ip_rdr) --- Looking up family names in type instances is a subtle affair. The family --- may be imported, in which case we need to lookup the occurence of a global --- name. Alternatively, the family may be in the same binding group (and in --- fact in a declaration processed later), and we need to create a new top --- source binder. +-- If the family is declared locally, it will not yet be in the main +-- environment; hence, we pass in an extra one here, which we check first. +-- See "Note [Looking up family names in family instances]" in 'RnNames'. -- --- So, also this is strictly speaking an occurence, we cannot raise an error --- message yet for instances without a family declaration. This will happen --- during renaming the type instance declaration in RnSource.rnTyClDecl. --- -lookupFamInstDeclBndr :: Module -> Located RdrName -> RnM Name -lookupFamInstDeclBndr mod lrdr_name@(L _ rdr_name) - = do { mb_gre <- lookupGreRn_maybe rdr_name - ; case mb_gre of - Just gre -> returnM (gre_name gre) - Nothing -> newTopSrcBinder mod lrdr_name } +lookupFamInstDeclBndr :: GlobalRdrEnv -> Located RdrName -> RnM Name +lookupFamInstDeclBndr tyclGroupEnv (L loc rdr_name) + = setSrcSpan loc $ + case lookupGRE_RdrName rdr_name tyclGroupEnv of + (gre:_) -> return $ gre_name gre + -- if there is more than one, an error will be raised elsewhere + [] -> lookupOccRn rdr_name +\end{code} + +Note [Usage for sub-bndrs] +~~~~~~~~~~~~~~~~~~~~~~~~~~ +If you have this + import qualified M( C( f ) ) + intance M.C T where + f x = x +then is the qualified import M.f used? Obviously yes. +But the RdrName used in the instance decl is unqualified. In effect, +we fill in the qualification by looking for f's whose class is M.C +But when adding to the UsedRdrNames we must make that qualification +explicit, otherwise we get "Redundant import of M.C". -------------------------------------------------- -- Occurrences -------------------------------------------------- +\begin{code} getLookupOccRn :: RnM (Name -> Maybe Name) getLookupOccRn = getLocalRdrEnv `thenM` \ local_env -> @@ -342,7 +361,7 @@ lookupOccRn :: RdrName -> RnM Name lookupOccRn rdr_name = getLocalRdrEnv `thenM` \ local_env -> case lookupLocalRdrEnv local_env rdr_name of - Just name -> returnM name + Just name -> return name Nothing -> lookupGlobalOccRn rdr_name lookupLocatedGlobalOccRn :: Located RdrName -> RnM (Located Name) @@ -350,51 +369,43 @@ lookupLocatedGlobalOccRn = wrapLocM lookupGlobalOccRn lookupGlobalOccRn :: RdrName -> RnM Name -- lookupGlobalOccRn is like lookupOccRn, except that it looks in the global --- environment. It's used only for --- record field names --- class op names in class and instance decls +-- environment. Adds an error message if the RdrName is not in scope. +-- Also has a special case for GHCi. lookupGlobalOccRn rdr_name - | not (isSrcRdrName rdr_name) - = lookupImportedName rdr_name + = do { -- First look up the name in the normal environment. + mb_name <- lookupGlobalOccRn_maybe rdr_name + ; case mb_name of { + Just n -> return n ; + Nothing -> do + + { -- We allow qualified names on the command line to refer to + -- *any* name exported by any module in scope, just as if there + -- was an "import qualified M" declaration for every module. + allow_qual <- doptM Opt_ImplicitImportQualified + ; mod <- getModule + -- This test is not expensive, + -- and only happens for failed lookups + ; if isQual rdr_name && allow_qual && mod == iNTERACTIVE + then lookupQualifiedName rdr_name + else unboundName rdr_name } } } + +lookupGlobalOccRn_maybe :: RdrName -> RnM (Maybe Name) +-- No filter function; does not report an error on failure + +lookupGlobalOccRn_maybe rdr_name + | Just n <- isExact_maybe rdr_name -- This happens in derived code + = return (Just n) - | otherwise - = -- First look up the name in the normal environment. - lookupGreRn_maybe rdr_name `thenM` \ mb_gre -> - case mb_gre of { - Just gre -> returnM (gre_name gre) ; - Nothing -> - - -- We allow qualified names on the command line to refer to - -- *any* name exported by any module in scope, just as if - -- there was an "import qualified M" declaration for every - -- module. - getModule `thenM` \ mod -> - if isQual rdr_name && mod == iNTERACTIVE then - -- This test is not expensive, - lookupQualifiedName rdr_name -- and only happens for failed lookups - else do - traceRn $ text "lookupGlobalOccRn" - unboundName rdr_name } - -lookupImportedName :: RdrName -> TcRnIf m n Name --- Lookup the occurrence of an imported name --- The RdrName is *always* qualified or Exact --- Treat it as an original name, and conjure up the Name --- Usually it's Exact or Orig, but it can be Qual if it --- comes from an hi-boot file. (This minor infelicity is --- just to reduce duplication in the parser.) -lookupImportedName rdr_name - | Just n <- isExact_maybe rdr_name - -- This happens in derived code - = returnM n - - -- Always Orig, even when reading a .hi-boot file | Just (rdr_mod, rdr_occ) <- isOrig_maybe rdr_name - = lookupOrig rdr_mod rdr_occ + = do { n <- lookupOrig rdr_mod rdr_occ; return (Just n) } | otherwise - = pprPanic "RnEnv.lookupImportedName" (ppr rdr_name) + = do { mb_gre <- lookupGreRn_maybe rdr_name + ; case mb_gre of + Nothing -> return Nothing + Just gre -> return (Just (gre_name gre)) } + unboundName :: RdrName -> RnM Name unboundName rdr_name @@ -403,21 +414,12 @@ unboundName rdr_name ; traceRn (vcat [unknownNameErr rdr_name, ptext (sLit "Global envt is:"), nest 3 (pprGlobalRdrEnv env)]) - ; returnM (mkUnboundName rdr_name) } + ; return (mkUnboundName rdr_name) } -------------------------------------------------- -- Lookup in the Global RdrEnv of the module -------------------------------------------------- -lookupSrcOcc_maybe :: RdrName -> RnM (Maybe Name) --- No filter function; does not report an error on failure -lookupSrcOcc_maybe rdr_name - = do { mb_gre <- lookupGreRn_maybe rdr_name - ; case mb_gre of - Nothing -> returnM Nothing - Just gre -> returnM (Just (gre_name gre)) } - -------------------------- lookupGreRn_maybe :: RdrName -> RnM (Maybe GlobalRdrElt) -- Just look up the RdrName in the GlobalRdrEnv lookupGreRn_maybe rdr_name @@ -450,10 +452,28 @@ lookupGreRn_help :: RdrName -- Only used in error message lookupGreRn_help rdr_name lookup = do { env <- getGlobalRdrEnv ; case lookup env of - [] -> returnM Nothing - [gre] -> returnM (Just gre) + [] -> return Nothing + [gre] -> do { addUsedRdrName gre rdr_name + ; return (Just gre) } gres -> do { addNameClashErrRn rdr_name gres - ; returnM (Just (head gres)) } } + ; return (Just (head gres)) } } + +addUsedRdrName :: GlobalRdrElt -> RdrName -> RnM () +-- Record usage of imported RdrNames +addUsedRdrName gre rdr + | isLocalGRE gre = return () + | otherwise = do { env <- getGblEnv + ; updMutVar (tcg_used_rdrnames env) + (\s -> Set.insert rdr s) } + +addUsedRdrNames :: [RdrName] -> RnM () +-- Record used sub-binders +-- We don't check for imported-ness here, because it's inconvenient +-- and not stritly necessary. +addUsedRdrNames rdrs + = do { env <- getGblEnv + ; updMutVar (tcg_used_rdrnames env) + (\s -> foldr Set.insert s rdrs) } ------------------------------ -- GHCi support @@ -466,7 +486,7 @@ lookupQualifiedName rdr_name | Just (mod,occ) <- isQual_maybe rdr_name -- Note: we want to behave as we would for a source file import here, -- and respect hiddenness of modules/packages, hence loadSrcInterface. - = loadSrcInterface doc mod False `thenM` \ iface -> + = loadSrcInterface doc mod False Nothing `thenM` \ iface -> case [ (mod,occ) | (mod,avails) <- mi_exports iface, @@ -483,6 +503,120 @@ lookupQualifiedName rdr_name doc = ptext (sLit "Need to find") <+> ppr rdr_name \end{code} +lookupSigOccRn is used for type signatures and pragmas +Is this valid? + module A + import M( f ) + f :: Int -> Int + f x = x +It's clear that the 'f' in the signature must refer to A.f +The Haskell98 report does not stipulate this, but it will! +So we must treat the 'f' in the signature in the same way +as the binding occurrence of 'f', using lookupBndrRn + +However, consider this case: + import M( f ) + f :: Int -> Int + g x = x +We don't want to say 'f' is out of scope; instead, we want to +return the imported 'f', so that later on the reanamer will +correctly report "misplaced type sig". + +\begin{code} +lookupSigOccRn :: Maybe NameSet -- Just ns => source file; these are the binders + -- in the same group + -- Nothing => hs-boot file; signatures without + -- binders are expected + -> Sig RdrName + -> Located RdrName -> RnM (Located Name) +lookupSigOccRn mb_bound_names sig + = wrapLocM $ \ rdr_name -> + do { mb_name <- lookupBindGroupOcc mb_bound_names (hsSigDoc sig) rdr_name + ; case mb_name of + Left err -> do { addErr err; return (mkUnboundName rdr_name) } + Right name -> return name } + +lookupBindGroupOcc :: Maybe NameSet -- Just ns => source file; these are the binders + -- in the same group + -- Nothing => hs-boot file; signatures without + -- binders are expected + -> SDoc + -> RdrName -> RnM (Either Message Name) +-- Looks up the RdrName, expecting it to resolve to one of the +-- bound names passed in. If not, return an appropriate error message +lookupBindGroupOcc mb_bound_names what rdr_name + = do { local_env <- getLocalRdrEnv + ; case lookupLocalRdrEnv local_env rdr_name of + Just n -> check_local_name n + Nothing -> do -- Not defined in a nested scope + + { env <- getGlobalRdrEnv + ; let gres = lookupGlobalRdrEnv env (rdrNameOcc rdr_name) + ; case (filter isLocalGRE gres) of + (gre:_) -> check_local_name (gre_name gre) + -- If there is more than one local GRE for the + -- same OccName, that will be reported separately + [] | null gres -> bale_out_with empty + | otherwise -> bale_out_with import_msg + }} + where + check_local_name name -- The name is in scope, and not imported + = case mb_bound_names of + Just bound_names | not (name `elemNameSet` bound_names) + -> bale_out_with local_msg + _other -> return (Right name) + + bale_out_with msg + = return (Left (sep [ ptext (sLit "The") <+> what + <+> ptext (sLit "for") <+> quotes (ppr rdr_name) + , nest 2 $ ptext (sLit "lacks an accompanying binding")] + $$ nest 2 msg)) + + local_msg = parens $ ptext (sLit "The") <+> what <+> ptext (sLit "must be given where") + <+> quotes (ppr rdr_name) <+> ptext (sLit "is declared") + + import_msg = parens $ ptext (sLit "You cannot give a") <+> what + <+> ptext (sLit "for an imported value") + +--------------- +lookupLocalDataTcNames :: NameSet -> SDoc -> RdrName -> RnM [Name] +-- GHC extension: look up both the tycon and data con +-- for con-like things +-- Complain if neither is in scope +lookupLocalDataTcNames bound_names what rdr_name + | Just n <- isExact_maybe rdr_name + -- Special case for (:), which doesn't get into the GlobalRdrEnv + = return [n] -- For this we don't need to try the tycon too + | otherwise + = do { mb_gres <- mapM (lookupBindGroupOcc (Just bound_names) what) + (dataTcOccs rdr_name) + ; let (errs, names) = splitEithers mb_gres + ; when (null names) (addErr (head errs)) -- Bleat about one only + ; return names } + +dataTcOccs :: RdrName -> [RdrName] +-- If the input is a data constructor, return both it and a type +-- constructor. This is useful when we aren't sure which we are +-- looking at. +dataTcOccs rdr_name + | Just n <- isExact_maybe rdr_name -- Ghastly special case + , n `hasKey` consDataConKey = [rdr_name] -- see note below + | isDataOcc occ = [rdr_name, rdr_name_tc] + | otherwise = [rdr_name] + where + occ = rdrNameOcc rdr_name + rdr_name_tc = setRdrNameSpace rdr_name tcName + +-- If the user typed "[]" or "(,,)", we'll generate an Exact RdrName, +-- and setRdrNameSpace generates an Orig, which is fine +-- But it's not fine for (:), because there *is* no corresponding type +-- constructor. If we generate an Orig tycon for GHC.Base.(:), it'll +-- appear to be in scope (because Orig's simply allocate a new name-cache +-- entry) and then we get an error when we use dataTcOccs in +-- TcRnDriver.tcRnGetInfo. Large sigh. +\end{code} + + %********************************************************* %* * Fixities @@ -517,7 +651,6 @@ type MiniFixityEnv = FastStringEnv (Located Fixity) -------------------------------- -- Used for nested fixity decls to bind names along with their fixities. -- the fixities are given as a UFM from an OccName's FastString to a fixity decl --- Also check for unused binders bindLocalNamesFV_WithFixities :: [Name] -> MiniFixityEnv -> RnM (a, FreeVars) -> RnM (a, FreeVars) @@ -580,7 +713,7 @@ lookupFixityRn name loadInterfaceForName doc name `thenM` \ iface -> do { traceRn (text "lookupFixityRn: looking up name in iface cache and found:" <+> vcat [ppr name, ppr $ mi_fix_fn iface (nameOccName name)]); - returnM (mi_fix_fn iface (nameOccName name)) + return (mi_fix_fn iface (nameOccName name)) } where doc = ptext (sLit "Checking fixity for") <+> ppr name @@ -589,45 +722,6 @@ lookupFixityRn name lookupTyFixityRn :: Located Name -> RnM Fixity lookupTyFixityRn (L _ n) = lookupFixityRn n ---------------- -lookupLocalDataTcNames :: RdrName -> RnM [Name] --- GHC extension: look up both the tycon and data con --- for con-like things --- Complain if neither is in scope -lookupLocalDataTcNames rdr_name - | Just n <- isExact_maybe rdr_name - -- Special case for (:), which doesn't get into the GlobalRdrEnv - = return [n] -- For this we don't need to try the tycon too - | otherwise - = do { mb_gres <- mapM lookupGreLocalRn (dataTcOccs rdr_name) - ; case [gre_name gre | Just gre <- mb_gres] of - [] -> do { - -- run for error reporting - ; unboundName rdr_name - ; return [] } - names -> return names - } - -dataTcOccs :: RdrName -> [RdrName] --- If the input is a data constructor, return both it and a type --- constructor. This is useful when we aren't sure which we are --- looking at. -dataTcOccs rdr_name - | Just n <- isExact_maybe rdr_name -- Ghastly special case - , n `hasKey` consDataConKey = [rdr_name] -- see note below - | isDataOcc occ = [rdr_name_tc, rdr_name] - | otherwise = [rdr_name] - where - occ = rdrNameOcc rdr_name - rdr_name_tc = setRdrNameSpace rdr_name tcName - --- If the user typed "[]" or "(,,)", we'll generate an Exact RdrName, --- and setRdrNameSpace generates an Orig, which is fine --- But it's not fine for (:), because there *is* no corresponding type --- constructor. If we generate an Orig tycon for GHC.Base.(:), it'll --- appear to be in scope (because Orig's simply allocate a new name-cache --- entry) and then we get an error when we use dataTcOccs in --- TcRnDriver.tcRnGetInfo. Large sigh. \end{code} %************************************************************************ @@ -678,9 +772,9 @@ lookupSyntaxName std_name else -- Get the similarly named thing from the local environment lookupOccRn (mkRdrUnqual (nameOccName std_name)) `thenM` \ usr_name -> - returnM (HsVar usr_name, unitFV usr_name) + return (HsVar usr_name, unitFV usr_name) where - normal_case = returnM (HsVar std_name, emptyFVs) + normal_case = return (HsVar std_name, emptyFVs) lookupSyntaxTable :: [Name] -- Standard names -> RnM (SyntaxTable Name, FreeVars) -- See comments with HsExpr.ReboundNames @@ -689,11 +783,11 @@ lookupSyntaxTable std_names if implicit_prelude then normal_case else -- Get the similarly named thing from the local environment - mappM (lookupOccRn . mkRdrUnqual . nameOccName) std_names `thenM` \ usr_names -> + mapM (lookupOccRn . mkRdrUnqual . nameOccName) std_names `thenM` \ usr_names -> - returnM (std_names `zip` map HsVar usr_names, mkFVs usr_names) + return (std_names `zip` map HsVar usr_names, mkFVs usr_names) where - normal_case = returnM (std_names `zip` map HsVar std_names, emptyFVs) + normal_case = return (std_names `zip` map HsVar std_names, emptyFVs) \end{code} @@ -704,74 +798,77 @@ lookupSyntaxTable std_names %********************************************************* \begin{code} -newLocalsRn :: [Located RdrName] -> RnM [Name] -newLocalsRn rdr_names_w_loc - = newUniqueSupply `thenM` \ us -> - returnM (zipWith mk rdr_names_w_loc (uniqsFromSupply us)) - where - mk (L loc rdr_name) uniq - | Just name <- isExact_maybe rdr_name = name - -- This happens in code generated by Template Haskell - | otherwise = ASSERT2( isUnqual rdr_name, ppr rdr_name ) - -- We only bind unqualified names here - -- lookupRdrEnv doesn't even attempt to look up a qualified RdrName - mkInternalName uniq (rdrNameOcc rdr_name) loc +newLocalBndrRn :: Located RdrName -> RnM Name +-- Used for non-top-level binders. These should +-- never be qualified. +newLocalBndrRn (L loc rdr_name) + | Just name <- isExact_maybe rdr_name + = return name -- This happens in code generated by Template Haskell + -- although I'm not sure why. Perhpas it's the call + -- in RnPat.newName LetMk? + | otherwise + = do { unless (isUnqual rdr_name) + (addErrAt loc (badQualBndrErr rdr_name)) + ; uniq <- newUnique + ; return (mkInternalName uniq (rdrNameOcc rdr_name) loc) } ---------------------- -checkDupAndShadowedRdrNames :: SDoc -> [Located RdrName] -> RnM () -checkDupAndShadowedRdrNames doc loc_rdr_names - = do { checkDupRdrNames doc loc_rdr_names - ; envs <- getRdrEnvs - ; checkShadowedNames doc envs - [(loc,rdrNameOcc rdr) | L loc rdr <- loc_rdr_names] } +newLocalBndrsRn :: [Located RdrName] -> RnM [Name] +newLocalBndrsRn = mapM newLocalBndrRn --------------------- -bindLocatedLocalsRn :: SDoc -- Documentation string for error message - -> [Located RdrName] +bindLocatedLocalsRn :: [Located RdrName] -> ([Name] -> RnM a) -> RnM a -bindLocatedLocalsRn doc_str rdr_names_w_loc enclosed_scope - = checkDupAndShadowedRdrNames doc_str rdr_names_w_loc `thenM_` +bindLocatedLocalsRn rdr_names_w_loc enclosed_scope + = do { checkDupAndShadowedRdrNames rdr_names_w_loc -- Make fresh Names and extend the environment - newLocalsRn rdr_names_w_loc `thenM` \names -> - bindLocalNames names (enclosed_scope names) + ; names <- newLocalBndrsRn rdr_names_w_loc + ; bindLocalNames names (enclosed_scope names) } bindLocalNames :: [Name] -> RnM a -> RnM a bindLocalNames names enclosed_scope - = getLocalRdrEnv `thenM` \ name_env -> - setLocalRdrEnv (extendLocalRdrEnv name_env names) - enclosed_scope + = do { name_env <- getLocalRdrEnv + ; setLocalRdrEnv (extendLocalRdrEnvList name_env names) + enclosed_scope } + +bindLocalName :: Name -> RnM a -> RnM a +bindLocalName name enclosed_scope + = do { name_env <- getLocalRdrEnv + ; setLocalRdrEnv (extendLocalRdrEnv name_env name) + enclosed_scope } bindLocalNamesFV :: [Name] -> RnM (a, FreeVars) -> RnM (a, FreeVars) bindLocalNamesFV names enclosed_scope = do { (result, fvs) <- bindLocalNames names enclosed_scope - ; returnM (result, delListFromNameSet fvs names) } + ; return (result, delListFromNameSet fvs names) } ------------------------------------- -- binLocalsFVRn is the same as bindLocalsRn -- except that it deals with free vars -bindLocatedLocalsFV :: SDoc -> [Located RdrName] +bindLocatedLocalsFV :: [Located RdrName] -> ([Name] -> RnM (a,FreeVars)) -> RnM (a, FreeVars) -bindLocatedLocalsFV doc rdr_names enclosed_scope - = bindLocatedLocalsRn doc rdr_names $ \ names -> +bindLocatedLocalsFV rdr_names enclosed_scope + = bindLocatedLocalsRn rdr_names $ \ names -> enclosed_scope names `thenM` \ (thing, fvs) -> - returnM (thing, delListFromNameSet fvs names) + return (thing, delListFromNameSet fvs names) ------------------------------------- -bindTyVarsRn :: SDoc -> [LHsTyVarBndr RdrName] +bindTyVarsRn :: [LHsTyVarBndr RdrName] -> ([LHsTyVarBndr Name] -> RnM a) -> RnM a -- Haskell-98 binding of type variables; e.g. within a data type decl -bindTyVarsRn doc_str tyvar_names enclosed_scope - = let - located_tyvars = hsLTyVarLocNames tyvar_names - in - bindLocatedLocalsRn doc_str located_tyvars $ \ names -> - enclosed_scope (zipWith replace tyvar_names names) - where - replace (L loc n1) n2 = L loc (replaceTyVarName n1 n2) +bindTyVarsRn tyvar_names enclosed_scope + = bindLocatedLocalsRn located_tyvars $ \ names -> + do { kind_sigs_ok <- doptM Opt_KindSignatures + ; unless (null kinded_tyvars || kind_sigs_ok) + (mapM_ (addErr . kindSigErr) kinded_tyvars) + ; enclosed_scope (zipWith replace tyvar_names names) } + where + replace (L loc n1) n2 = L loc (replaceTyVarName n1 n2) + located_tyvars = hsLTyVarLocNames tyvar_names + kinded_tyvars = [n | L _ (KindedTyVar n _) <- tyvar_names] bindPatSigTyVars :: [LHsType RdrName] -> ([Name] -> RnM a) -> RnM a -- Find the type variables in the pattern type @@ -790,9 +887,7 @@ bindPatSigTyVars tys thing_inside -- f (x :: t) (y :: t) = .... -- We don't want to complain about binding t twice! - ; bindLocatedLocalsRn doc_sig nubbed_tvs thing_inside }} - where - doc_sig = text "In a pattern type-signature" + ; bindLocatedLocalsRn nubbed_tvs thing_inside }} bindPatSigTyVarsFV :: [LHsType RdrName] -> RnM (a, FreeVars) @@ -800,7 +895,7 @@ bindPatSigTyVarsFV :: [LHsType RdrName] bindPatSigTyVarsFV tys thing_inside = bindPatSigTyVars tys $ \ tvs -> thing_inside `thenM` \ (result,fvs) -> - returnM (result, fvs `delListFromNameSet` tvs) + return (result, fvs `delListFromNameSet` tvs) bindSigTyVarsFV :: [Name] -> RnM (a, FreeVars) @@ -817,41 +912,72 @@ extendTyVarEnvFVRn :: [Name] -> RnM (a, FreeVars) -> RnM (a, FreeVars) extendTyVarEnvFVRn tyvars thing_inside = bindLocalNamesFV tyvars thing_inside ------------------------------------- -checkDupRdrNames :: SDoc - -> [Located RdrName] - -> RnM () -checkDupRdrNames doc_str rdr_names_w_loc +checkDupRdrNames :: [Located RdrName] -> RnM () +checkDupRdrNames rdr_names_w_loc = -- Check for duplicated names in a binding group - mappM_ (dupNamesErr getLoc doc_str) dups + mapM_ (dupNamesErr getLoc) dups where (_, dups) = removeDups (\n1 n2 -> unLoc n1 `compare` unLoc n2) rdr_names_w_loc -checkDupNames :: SDoc - -> [Name] - -> RnM () -checkDupNames doc_str names +checkDupNames :: [Name] -> RnM () +checkDupNames names = -- Check for duplicated names in a binding group - mappM_ (dupNamesErr nameSrcSpan doc_str) dups + mapM_ (dupNamesErr nameSrcSpan) dups where (_, dups) = removeDups (\n1 n2 -> nameOccName n1 `compare` nameOccName n2) names +--------------------- +checkDupAndShadowedRdrNames :: [Located RdrName] -> RnM () +checkDupAndShadowedRdrNames loc_rdr_names + = do { checkDupRdrNames loc_rdr_names + ; envs <- getRdrEnvs + ; checkShadowedOccs envs loc_occs } + where + loc_occs = [(loc,rdrNameOcc rdr) | L loc rdr <- loc_rdr_names] + +checkDupAndShadowedNames :: (GlobalRdrEnv, LocalRdrEnv) -> [Name] -> RnM () +checkDupAndShadowedNames envs names + = do { checkDupNames names + ; checkShadowedOccs envs loc_occs } + where + loc_occs = [(nameSrcSpan name, nameOccName name) | name <- names] + ------------------------------------- -checkShadowedNames :: SDoc -> (GlobalRdrEnv, LocalRdrEnv) -> [(SrcSpan,OccName)] -> RnM () -checkShadowedNames doc_str (global_env,local_env) loc_rdr_names +checkShadowedOccs :: (GlobalRdrEnv, LocalRdrEnv) -> [(SrcSpan,OccName)] -> RnM () +checkShadowedOccs (global_env,local_env) loc_occs = ifOptM Opt_WarnNameShadowing $ - do { traceRn (text "shadow" <+> ppr loc_rdr_names) - ; mappM_ check_shadow loc_rdr_names } + do { traceRn (text "shadow" <+> ppr loc_occs) + ; mapM_ check_shadow loc_occs } where check_shadow (loc, occ) + | startsWithUnderscore occ = return () -- Do not report shadowing for "_x" + -- See Trac #3262 | Just n <- mb_local = complain [ptext (sLit "bound at") <+> ppr (nameSrcLoc n)] - | not (null gres) = complain (map pprNameProvenance gres) - | otherwise = return () + | otherwise = do { gres' <- filterM is_shadowed_gre gres + ; complain (map pprNameProvenance gres') } where - complain pp_locs = addWarnAt loc (shadowedNameWarn doc_str occ pp_locs) + complain [] = return () + complain pp_locs = addWarnAt loc (shadowedNameWarn occ pp_locs) mb_local = lookupLocalRdrOcc local_env occ gres = lookupGRE_RdrName (mkRdrUnqual occ) global_env -- Make an Unqualified RdrName and look that up, so that -- we don't find any GREs that are in scope qualified-only + + is_shadowed_gre :: GlobalRdrElt -> RnM Bool + -- Returns False for record selectors that are shadowed, when + -- punning or wild-cards are on (cf Trac #2723) + is_shadowed_gre gre@(GRE { gre_par = ParentIs _ }) + = do { dflags <- getDOpts + ; if (dopt Opt_RecordPuns dflags || dopt Opt_RecordWildCards dflags) + then do { is_fld <- is_rec_fld gre; return (not is_fld) } + else return True } + is_shadowed_gre _other = return True + + is_rec_fld gre -- Return True for record selector ids + | isLocalGRE gre = do { RecFields _ fld_set <- getRecFieldEnv + ; return (gre_name gre `elemNameSet` fld_set) } + | otherwise = do { sel_id <- tcLookupField (gre_name gre) + ; return (isRecordSelector sel_id) } \end{code} @@ -863,12 +989,18 @@ checkShadowedNames doc_str (global_env,local_env) loc_rdr_names \begin{code} -- A useful utility +addFvRn :: FreeVars -> RnM (thing, FreeVars) -> RnM (thing, FreeVars) +addFvRn fvs1 thing_inside = do { (res, fvs2) <- thing_inside + ; return (res, fvs1 `plusFV` fvs2) } + mapFvRn :: (a -> RnM (b, FreeVars)) -> [a] -> RnM ([b], FreeVars) -mapFvRn f xs = mappM f xs `thenM` \ stuff -> - let - (ys, fvs_s) = unzip stuff - in - returnM (ys, plusFVs fvs_s) +mapFvRn f xs = do stuff <- mapM f xs + case unzip stuff of + (ys, fvs_s) -> return (ys, plusFVs fvs_s) + +mapMaybeFvRn :: (a -> RnM (b, FreeVars)) -> Maybe a -> RnM (Maybe b, FreeVars) +mapMaybeFvRn _ Nothing = return (Nothing, emptyFVs) +mapMaybeFvRn f (Just x) = do { (y, fvs) <- f x; return (Just y, fvs) } -- because some of the rename functions are CPSed: -- maps the function across the list from left to right; @@ -892,7 +1024,7 @@ mapFvRnCPS f (x:xs) cont = f x $ \ x' -> \begin{code} warnUnusedModules :: [(ModuleName,SrcSpan)] -> RnM () warnUnusedModules mods - = ifOptM Opt_WarnUnusedImports (mappM_ bleat mods) + = ifOptM Opt_WarnUnusedImports (mapM_ bleat mods) where bleat (mod,loc) = addWarnAt loc (mk_warn mod) mk_warn m = vcat [ptext (sLit "Module") <+> quotes (ppr m) @@ -926,18 +1058,18 @@ warnUnusedLocals names = warnUnusedBinds [(n,LocalDef) | n<-names] warnUnusedBinds :: [(Name,Provenance)] -> RnM () -warnUnusedBinds names = mappM_ warnUnusedName (filter reportable names) +warnUnusedBinds names = mapM_ warnUnusedName (filter reportable names) where reportable (name,_) | isWiredInName name = False -- Don't report unused wired-in names -- Otherwise we get a zillion warnings -- from Data.Tuple - | otherwise = reportIfUnused (nameOccName name) + | otherwise = not (startsWithUnderscore (nameOccName name)) ------------------------- warnUnusedName :: (Name, Provenance) -> RnM () warnUnusedName (name, LocalDef) - = addUnusedWarning name (srcLocSpan (nameSrcLoc name)) + = addUnusedWarning name (nameSrcSpan name) (ptext (sLit "Defined but not used")) warnUnusedName (name, Imported is) @@ -968,12 +1100,11 @@ addNameClashErrRn rdr_name names msgs = [ptext (sLit " or") <+> mk_ref np | np <- nps] mk_ref gre = quotes (ppr (gre_name gre)) <> comma <+> pprNameProvenance gre -shadowedNameWarn :: SDoc -> OccName -> [SDoc] -> SDoc -shadowedNameWarn doc occ shadowed_locs +shadowedNameWarn :: OccName -> [SDoc] -> SDoc +shadowedNameWarn occ shadowed_locs = sep [ptext (sLit "This binding for") <+> quotes (ppr occ) <+> ptext (sLit "shadows the existing binding") <> plural shadowed_locs, nest 2 (vcat shadowed_locs)] - $$ doc unknownNameErr :: RdrName -> SDoc unknownNameErr rdr_name @@ -982,9 +1113,13 @@ unknownNameErr rdr_name <+> quotes (ppr rdr_name)) , extra ] where - extra | rdr_name == forall_tv_RDR - = ptext (sLit "Perhaps you intended to use -XRankNTypes or similar flag") - | otherwise = empty + extra | rdr_name == forall_tv_RDR = perhapsForallMsg + | otherwise = empty + +perhapsForallMsg :: SDoc +perhapsForallMsg + = vcat [ ptext (sLit "Perhaps you intended to use -XExplicitForAll or similar flag") + , ptext (sLit "to enable explicit-forall syntax: forall . ")] unknownSubordinateErr :: SDoc -> RdrName -> SDoc unknownSubordinateErr doc op -- Doc is "method of class" or @@ -996,20 +1131,28 @@ badOrigBinding name = ptext (sLit "Illegal binding of built-in syntax:") <+> ppr (rdrNameOcc name) -- The rdrNameOcc is because we don't want to print Prelude.(,) -dupNamesErr :: Outputable n => (n -> SrcSpan) -> SDoc -> [n] -> RnM () -dupNamesErr get_loc descriptor names +dupNamesErr :: Outputable n => (n -> SrcSpan) -> [n] -> RnM () +dupNamesErr get_loc names = addErrAt big_loc $ vcat [ptext (sLit "Conflicting definitions for") <+> quotes (ppr (head names)), - locations, descriptor] + locations] where locs = map get_loc names big_loc = foldr1 combineSrcSpans locs - one_line = isOneLineSpan big_loc - locations | one_line = empty - | otherwise = ptext (sLit "Bound at:") <+> - vcat (map ppr (sortLe (<=) locs)) + locations = ptext (sLit "Bound at:") <+> vcat (map ppr (sortLe (<=) locs)) + +kindSigErr :: Outputable a => a -> SDoc +kindSigErr thing + = hang (ptext (sLit "Illegal kind signature for") <+> quotes (ppr thing)) + 2 (ptext (sLit "Perhaps you intended to use -XKindSignatures")) + badQualBndrErr :: RdrName -> SDoc badQualBndrErr rdr_name = ptext (sLit "Qualified name in binding position:") <+> ppr rdr_name + +opDeclErr :: RdrName -> SDoc +opDeclErr n + = hang (ptext (sLit "Illegal declaration of a type or class operator") <+> quotes (ppr n)) + 2 (ptext (sLit "Use -XTypeOperators to declare operators in type and declarations")) \end{code}