X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Fcompiler%2Frename%2FRnNames.lhs;h=8773732c6ddb16e406b9ec2872ce42503d1414cc;hb=3e12bb2d764b45563000ab3074dac61d22853321;hp=9b172cfabd3b16c45e52ff467e92f1160ddc485f;hpb=ef5b4b146aa172d8ac10f39b5eb3d7a0f948d8f1;p=ghc-hetmet.git diff --git a/ghc/compiler/rename/RnNames.lhs b/ghc/compiler/rename/RnNames.lhs index 9b172cf..8773732 100644 --- a/ghc/compiler/rename/RnNames.lhs +++ b/ghc/compiler/rename/RnNames.lhs @@ -5,17 +5,17 @@ \begin{code} module RnNames ( - rnImports, importsFromLocalDecls, exportsFromAvail, + rnImports, importsFromLocalDecls, reportUnusedNames, reportDeprecations, - mkModDeps, exportsToAvails + mkModDeps, exportsToAvails, exportsFromAvail ) where #include "HsVersions.h" import CmdLineOpts ( DynFlag(..) ) import HsSyn ( IE(..), ieName, ImportDecl(..), LImportDecl, - ForeignDecl(..), HsGroup(..), - collectGroupBinders, tyClDeclNames + ForeignDecl(..), HsGroup(..), HsBindGroup(..), + Sig(..), collectGroupBinders, tyClDeclNames ) import RnEnv import IfaceEnv ( lookupOrig, newGlobalBinder ) @@ -26,20 +26,21 @@ import FiniteMap import PrelNames ( pRELUDE, isUnboundName, main_RDR_Unqual ) import Module ( Module, moduleUserString, unitModuleEnv, unitModuleEnv, - lookupModuleEnv, moduleEnvElts ) + lookupModuleEnv, moduleEnvElts, foldModuleEnv ) import Name ( Name, nameSrcLoc, nameOccName, nameModule, isWiredInName, nameParent, nameParent_maybe, isExternalName, isBuiltInSyntax ) import NameSet +import NameEnv import OccName ( srcDataName, isTcOcc, occNameFlavour, OccEnv, mkOccEnv, lookupOccEnv, emptyOccEnv, extendOccEnv ) -import HscTypes ( GenAvailInfo(..), AvailInfo, Avails, GhciMode(..), +import HscTypes ( GenAvailInfo(..), AvailInfo, GhciMode(..), IfaceExport, HomePackageTable, PackageIfaceTable, - availName, availNames, availsToNameSet, unQualInScope, + availNames, unQualInScope, Deprecs(..), ModIface(..), Dependencies(..), - lookupIface, ExternalPackageState(..), - IfacePackage(..) + lookupIface, ExternalPackageState(..) ) +import Packages ( PackageIdH(..) ) import RdrName ( RdrName, rdrNameOcc, setRdrNameSpace, GlobalRdrEnv, mkGlobalRdrEnv, GlobalRdrElt(..), emptyGlobalRdrEnv, plusGlobalRdrEnv, globalRdrEnvElts, @@ -47,7 +48,7 @@ import RdrName ( RdrName, rdrNameOcc, setRdrNameSpace, Provenance(..), ImportSpec(..), isLocalGRE, pprNameProvenance ) import Outputable -import Maybes ( isNothing, catMaybes, mapCatMaybes, seqMaybe ) +import Maybes ( isNothing, catMaybes, mapCatMaybes, seqMaybe, orElse ) import SrcLoc ( noSrcLoc, Located(..), mkGeneralSrcSpan, unLoc, noLoc, srcLocSpan, combineSrcSpans, SrcSpan ) import BasicTypes ( DeprecTxt ) @@ -74,9 +75,9 @@ rnImports imports -- Do the non {- SOURCE -} ones first, so that we get a helpful -- warning for {- SOURCE -} ones that are unnecessary this_mod <- getModule - ; opt_no_prelude <- doptM Opt_NoImplicitPrelude + ; implicit_prelude <- doptM Opt_ImplicitPrelude ; let - all_imports = mk_prel_imports this_mod opt_no_prelude ++ imports + all_imports = mk_prel_imports this_mod implicit_prelude ++ imports (source, ordinary) = partition is_source_import all_imports is_source_import (L _ (ImportDecl _ is_boot _ _ _)) = is_boot @@ -100,10 +101,10 @@ rnImports imports -- NB: opt_NoImplicitPrelude is slightly different to import Prelude (); -- because the former doesn't even look at Prelude.hi for instance -- declarations, whereas the latter does. - mk_prel_imports this_mod no_prelude + mk_prel_imports this_mod implicit_prelude | this_mod == pRELUDE || explicit_prelude_import - || no_prelude + || not implicit_prelude = [] | otherwise = [preludeImportDecl] @@ -182,7 +183,6 @@ importsFromImportDecl this_mod imp_spec = ImportSpec { is_mod = imp_mod_name, is_qual = qual_only, is_loc = loc, is_as = qual_mod_name } in - -- Get the total imports, and filter them according to the import list exportsToAvails filtered_exports `thenM` \ total_avails -> filterImports iface imp_spec @@ -199,7 +199,7 @@ importsFromImportDecl this_mod (dependent_mods, dependent_pkgs) = case mi_package iface of - ThisPackage -> + HomePackage -> -- Imported module is from the home package -- Take its dependent modules and add imp_mod itself -- Take its dependent packages unchanged @@ -213,7 +213,7 @@ importsFromImportDecl this_mod -- check. See LoadIface.loadHiBootInterface ((imp_mod_name, want_boot) : dep_mods deps, dep_pkgs deps) - ExternalPackage pkg -> + ExtPackage pkg -> -- Imported module is from another package -- Dump the dependent modules -- Add the package imp_mod comes from to the dependent packages @@ -231,8 +231,7 @@ importsFromImportDecl this_mod -- module M ( module P ) where ... -- Then we must export whatever came from P unqualified. imports = ImportAvails { - imp_qual = unitModuleEnv qual_mod_name avail_env, - imp_env = avail_env, + imp_env = unitModuleEnv qual_mod_name avail_env, imp_mods = unitModuleEnv imp_mod (imp_mod, import_all, loc), imp_orphs = orphans, imp_dep_mods = mkModDeps dependent_mods, @@ -248,23 +247,33 @@ importsFromImportDecl this_mod returnM (gbl_env, imports) -exportsToAvails :: [IfaceExport] -> TcRnIf gbl lcl Avails +exportsToAvails :: [IfaceExport] -> TcRnIf gbl lcl NameSet exportsToAvails exports - = do { avails_by_module <- mappM do_one exports - ; return (concat avails_by_module) } + = foldlM do_one emptyNameSet exports where - do_one (mod_name, exports) = mapM (do_avail mod_name) exports - do_avail mod (Avail n) = do { n' <- lookupOrig mod n; - ; return (Avail n') } - do_avail mod (AvailTC n ns) = do { n' <- lookupOrig mod n - ; ns' <- mappM (lookup_sub n') ns - ; return (AvailTC n' ns') } + do_one acc (mod, exports) = foldlM (do_avail mod) acc exports + do_avail mod acc (Avail n) = do { n' <- lookupOrig mod n; + ; return (addOneToNameSet acc n') } + do_avail mod acc (AvailTC p_occ occs) + = do { p_name <- lookupOrig mod p_occ + ; ns <- mappM (lookup_sub p_name) occs + ; return (addListToNameSet acc ns) } + -- Remember that 'occs' is all the exported things, including + -- the parent. It's possible to export just class ops without + -- the class, via C( op ). If the class was exported too we'd + -- have C( C, op ) where - lookup_sub parent occ = newGlobalBinder mod occ (Just parent) noSrcLoc - -- Hack alert! Notice the newGlobalBinder. It ensures that the subordinate - -- names record their parent; and that in turn ensures that the GlobalRdrEnv - -- has the correct parent for all the names in its range. - -- For imported things, we only suck in the binding site later, if ever. + lookup_sub parent occ + = newGlobalBinder mod occ mb_parent noSrcLoc + where + mb_parent | occ == p_occ = Nothing + | otherwise = Just parent + + -- The use of newGlobalBinder here (rather than lookupOrig) + -- ensures that the subordinate names record their parent; + -- and that in turn ensures that the GlobalRdrEnv + -- has the correct parent for all the names in its range. + -- For imported things, we may only suck in the interface later, if ever. -- Reason for all this: -- Suppose module M exports type A.T, and constructor A.MkT -- Then, we know that A.MkT is a subordinate name of A.T, @@ -311,7 +320,7 @@ importsFromLocalDecls group -- printer returns False. It seems awkward to fix, unfortunately. mappM_ addDupDeclErr dups `thenM_` - doptM Opt_NoImplicitPrelude `thenM` \ implicit_prelude -> + doptM Opt_ImplicitPrelude `thenM` \ implicit_prelude -> let prov = LocalDef this_mod gbl_env = mkGlobalRdrEnv gres @@ -328,26 +337,21 @@ importsFromLocalDecls group -- It's worth doing because it makes the environment smaller for -- every module that imports the Prelude -- - -- Note: don't filter the gbl_env (hence avails, not avails' in - -- defn of gbl_env above). Stupid reason: when parsing + -- Note: don't filter the gbl_env (hence all_names, not filered_all_names + -- in defn of gres above). Stupid reason: when parsing -- data type decls, the constructors start as Exact tycon-names, -- and then get turned into data con names by zapping the name space; -- but that stops them being Exact, so they get looked up. -- Ditto in fixity decls; e.g. infix 5 : -- Sigh. It doesn't matter because it only affects the Data.Tuple really. -- The important thing is to trim down the exports. + filtered_names + | implicit_prelude = all_names + | otherwise = filter (not . isBuiltInSyntax) all_names - avails' | implicit_prelude = filter not_built_in_syntax avails - | otherwise = avails - not_built_in_syntax a = not (all isBuiltInSyntax (availNames a)) - -- Only filter it if all the names of the avail are built-in - -- In particular, lists have (:) which is not built in syntax - -- so we don't filter it out. [Sept 03: wrong: see isBuiltInSyntax] - - avail_env = mkAvailEnv avails' - imports = emptyImportAvails { - imp_qual = unitModuleEnv this_mod avail_env, - imp_env = avail_env + imports = emptyImportAvails { + imp_env = unitModuleEnv this_mod $ + mkNameSet filtered_names } in returnM (gbl_env, imports) @@ -376,12 +380,21 @@ getLocalDeclBinders mod (HsGroup {hs_valds = val_decls, -- an export indicator because they are all implicitly exported. mappM new_tc tycl_decls `thenM` \ tc_avails -> - mappM new_simple (for_hs_bndrs ++ val_hs_bndrs) `thenM` \ simple_avails -> - returnM (tc_avails ++ simple_avails) + + -- In a hs-boot file, the value binders come from the + -- *signatures*, and there should be no foreign binders + tcIsHsBoot `thenM` \ is_hs_boot -> + let val_bndrs | is_hs_boot = sig_hs_bndrs + | otherwise = for_hs_bndrs ++ val_hs_bndrs + in + mappM new_simple val_bndrs `thenM` \ names -> + + returnM (tc_avails ++ map Avail names) where - new_simple rdr_name = newTopSrcBinder mod Nothing rdr_name `thenM` \ name -> - returnM (Avail name) + new_simple rdr_name = newTopSrcBinder mod Nothing rdr_name + sig_hs_bndrs = [nm | HsBindGroup _ lsigs _ <- val_decls, + L _ (Sig nm _) <- lsigs] val_hs_bndrs = collectGroupBinders val_decls for_hs_bndrs = [nm | L _ (ForeignImport nm _ _ _) <- foreign_decls] @@ -407,63 +420,59 @@ available, and filters it through the import spec (if any). filterImports :: ModIface -> ImportSpec -- The span for the entire import decl -> Maybe (Bool, [Located (IE RdrName)]) -- Import spec; True => hiding - -> [AvailInfo] -- What's available - -> RnM (AvailEnv, -- What's imported (qualified or unqualified) + -> NameSet -- What's available + -> RnM (NameSet, -- What's imported (qualified or unqualified) GlobalRdrEnv) -- Same again, but in GRE form -- Complains if import spec mentions things that the module doesn't export -- Warns/informs if import spec contains duplicates. -mkGenericRdrEnv imp_spec avails +mkGenericRdrEnv imp_spec names = mkGlobalRdrEnv [ GRE { gre_name = name, gre_prov = Imported [imp_spec] False } - | avail <- avails, name <- availNames avail ] + | name <- nameSetToList names ] -filterImports iface imp_spec Nothing total_avails - = returnM (mkAvailEnv total_avails, - mkGenericRdrEnv imp_spec total_avails) +filterImports iface imp_spec Nothing all_names + = returnM (all_names, mkGenericRdrEnv imp_spec all_names) -filterImports iface imp_spec (Just (want_hiding, import_items)) total_avails - = mapAndUnzipM (addLocM get_item) import_items `thenM` \ (avails_s, gres) -> +filterImports iface imp_spec (Just (want_hiding, import_items)) all_names + = mappM (addLocM get_item) import_items `thenM` \ gres_s -> let - avails = concat avails_s + gres = concat gres_s + specified_names = mkNameSet (map gre_name gres) in if not want_hiding then - return (mkAvailEnv avails, - foldr plusGlobalRdrEnv emptyGlobalRdrEnv gres) + return (specified_names, mkGlobalRdrEnv gres) else - let - hidden = availsToNameSet avails - keep n = not (n `elemNameSet` hidden) - pruned_avails = pruneAvails keep total_avails - in - return (mkAvailEnv pruned_avails, - mkGenericRdrEnv imp_spec pruned_avails) + let + keep n = not (n `elemNameSet` specified_names) + pruned_avails = filterNameSet keep all_names + in + return (pruned_avails, mkGenericRdrEnv imp_spec pruned_avails) where - import_fm :: OccEnv AvailInfo - import_fm = mkOccEnv [ (nameOccName name, avail) - | avail <- total_avails, - name <- availNames avail] - -- Even though availNames returns data constructors too, + occ_env :: OccEnv Name -- Maps OccName to corresponding Name + occ_env = mkOccEnv [(nameOccName n, n) | n <- nameSetToList all_names] + -- This env will have entries for data constructors too, -- they won't make any difference because naked entities like T -- in an import list map to TcOccs, not VarOccs. - bale_out item = addErr (badImportItemErr iface imp_spec item) `thenM_` - returnM ([], emptyGlobalRdrEnv) + sub_env :: NameEnv [Name] + sub_env = mkSubNameEnv all_names + + bale_out item = addErr (badImportItemErr iface imp_spec item) `thenM_` + returnM [] - succeed_with :: Bool -> AvailInfo -> RnM ([AvailInfo], GlobalRdrEnv) - succeed_with all_explicit avail + succeed_with :: Bool -> [Name] -> RnM [GlobalRdrElt] + succeed_with all_explicit names = do { loc <- getSrcSpanM - ; returnM ([avail], - mkGlobalRdrEnv (map (mk_gre loc) (availNames avail))) } + ; returnM (map (mk_gre loc) names) } where mk_gre loc name = GRE { gre_name = name, gre_prov = Imported [this_imp_spec loc] (explicit name) } this_imp_spec loc = imp_spec { is_loc = loc } - explicit name = all_explicit || name == main_name - main_name = availName avail + explicit name = all_explicit || isNothing (nameParent_maybe name) - get_item :: IE RdrName -> RnM ([AvailInfo], GlobalRdrEnv) + get_item :: IE RdrName -> RnM [GlobalRdrElt] -- Empty result for a bad item. -- Singleton result is typical case. -- Can have two when we are hiding, and mention C which might be @@ -473,82 +482,36 @@ filterImports iface imp_spec (Just (want_hiding, import_items)) total_avails get_item item@(IEThingAll tc) = case check_item item of - Nothing -> bale_out item - Just avail@(AvailTC _ [n]) -> -- This occurs when you import T(..), but - -- only export T abstractly. The single [n] - -- in the AvailTC is the type or class itself - ifOptM Opt_WarnDodgyImports (addWarn (dodgyImportWarn tc)) `thenM_` - succeed_with False avail - Just avail -> succeed_with False avail + [] -> bale_out item + + [n] -> -- This occurs when you import T(..), but + -- only export T abstractly. The single [n] + -- in the AvailTC is the type or class itself + ifOptM Opt_WarnDodgyImports (addWarn (dodgyImportWarn tc)) `thenM_` + succeed_with False [n] + + names -> succeed_with False names get_item item@(IEThingAbs n) | want_hiding -- hiding( C ) -- Here the 'C' can be a data constructor -- *or* a type/class, or even both - = case catMaybes [check_item item, check_item (IEVar data_n)] of - [] -> bale_out item - avails -> returnM (avails, emptyGlobalRdrEnv) - -- The GlobalRdrEnv result is irrelevant when hiding + = case concat [check_item item, check_item (IEVar data_n)] of + [] -> bale_out item + names -> succeed_with True names where data_n = setRdrNameSpace n srcDataName get_item item = case check_item item of - Nothing -> bale_out item - Just avail -> succeed_with True avail - - check_item item - | isNothing maybe_in_import_avails || - isNothing maybe_filtered_avail - = Nothing - - | otherwise - = Just filtered_avail - - where - wanted_occ = rdrNameOcc (ieName item) - maybe_in_import_avails = lookupOccEnv import_fm wanted_occ - - Just avail = maybe_in_import_avails - maybe_filtered_avail = filterAvail item avail - Just filtered_avail = maybe_filtered_avail -\end{code} - -\begin{code} -filterAvail :: IE RdrName -- Wanted - -> AvailInfo -- Available - -> Maybe AvailInfo -- Resulting available; - -- Nothing if (any of the) wanted stuff isn't there - -filterAvail ie@(IEThingWith want wants) avail@(AvailTC n ns) - | sub_names_ok = Just (AvailTC n (filter is_wanted ns)) - | otherwise = Nothing - where - is_wanted name = nameOccName name `elem` wanted_occs - sub_names_ok = all (`elem` avail_occs) wanted_occs - avail_occs = map nameOccName ns - wanted_occs = map rdrNameOcc (want:wants) - -filterAvail (IEThingAbs _) (AvailTC n ns) = ASSERT( n `elem` ns ) - Just (AvailTC n [n]) - -filterAvail (IEThingAbs _) avail@(Avail n) = Just avail -- Type synonyms - -filterAvail (IEVar _) avail@(Avail n) = Just avail -filterAvail (IEVar v) avail@(AvailTC n ns) = Just (AvailTC n (filter wanted ns)) - where - wanted n = nameOccName n == occ - occ = rdrNameOcc v - -- The second equation happens if we import a class op, thus - -- import A( op ) - -- where op is a class operation - -filterAvail (IEThingAll _) avail@(AvailTC _ _) = Just avail - -- We don't complain even if the IE says T(..), but - -- no constrs/class ops of T are available - -- Instead that's caught with a warning by the caller - -filterAvail ie avail = Nothing + [] -> bale_out item + names -> succeed_with True names + + check_item :: IE RdrName -> [Name] + check_item item + = case lookupOccEnv occ_env (rdrNameOcc (ieName item)) of + Nothing -> [] + Just name -> filterAvail item name sub_env \end{code} @@ -618,16 +581,15 @@ exports_from_avail Nothing rdr_env imports | gre <- globalRdrEnvElts rdr_env, isLocalGRE gre ]) -exports_from_avail (Just export_items) rdr_env - (ImportAvails { imp_qual = mod_avail_env, - imp_env = entity_avail_env }) - = foldlM (exports_from_litem) emptyExportAccum - export_items `thenM` \ (_, _, exports) -> +exports_from_avail (Just items) rdr_env (ImportAvails { imp_env = imp_env }) + = foldlM do_litem emptyExportAccum items `thenM` \ (_, _, exports) -> returnM exports - where - exports_from_litem :: ExportAccum -> Located (IE RdrName) -> RnM ExportAccum - exports_from_litem acc = addLocM (exports_from_item acc) + sub_env :: NameEnv [Name] -- Classify each name by its parent + sub_env = mkSubNameEnv (foldModuleEnv unionNameSets emptyNameSet imp_env) + + do_litem :: ExportAccum -> Located (IE RdrName) -> RnM ExportAccum + do_litem acc = addLocM (exports_from_item acc) exports_from_item :: ExportAccum -> IE RdrName -> RnM ExportAccum exports_from_item acc@(mods, occs, exports) ie@(IEModuleContents mod) @@ -637,52 +599,62 @@ exports_from_avail (Just export_items) rdr_env returnM acc } | otherwise - = case lookupModuleEnv mod_avail_env mod of + = case lookupModuleEnv imp_env mod of Nothing -> addErr (modExportErr mod) `thenM_` returnM acc - - Just avail_env + Just names -> let - new_exports = [ name | avail <- availEnvElts avail_env, - name <- availNames avail, - inScopeUnqual rdr_env name ] + new_exports = filterNameSet (inScopeUnqual rdr_env) names in -- This check_occs not only finds conflicts between this item -- and others, but also internally within this item. That is, -- if 'M.x' is in scope in several ways, we'll have several -- members of mod_avails with the same OccName. - check_occs ie occs new_exports `thenM` \ occs' -> - returnM (mod:mods, occs', addListToNameSet exports new_exports) + check_occs ie occs (nameSetToList new_exports) `thenM` \ occs' -> + returnM (mod:mods, occs', exports `unionNameSets` new_exports) exports_from_item acc@(mods, occs, exports) ie = lookupGlobalOccRn (ieName ie) `thenM` \ name -> if isUnboundName name then returnM acc -- Avoid error cascade - else - -- Get the AvailInfo for the parent of the specified name - let - parent = nameParent name - avail = lookupAvailEnv entity_avail_env parent + else let + new_exports = filterAvail ie name sub_env in - -- Filter out the bits we want - case filterAvail ie avail of { - Nothing -> -- Not enough availability - addErr (exportItemErr ie) `thenM_` - returnM acc ; - - Just export_avail -> - - -- Phew! It's OK! Now to check the occurrence stuff! - - let - new_exports = availNames export_avail - in - checkForDodgyExport ie new_exports `thenM_` - check_occs ie occs new_exports `thenM` \ occs' -> + checkErr (not (null new_exports)) (exportItemErr ie) `thenM_` + checkForDodgyExport ie new_exports `thenM_` + check_occs ie occs new_exports `thenM` \ occs' -> returnM (mods, occs', addListToNameSet exports new_exports) - } + +------------------------------- +filterAvail :: IE RdrName -- Wanted + -> Name -- The Name of the ieName of the item + -> NameEnv [Name] -- Maps type/class names to their sub-names + -> [Name] -- Empty if even one thing reqd is missing + +filterAvail (IEVar _) n subs = [n] +filterAvail (IEThingAbs _) n subs = [n] +filterAvail (IEThingAll _) n subs = n : subNames subs n +filterAvail (IEThingWith _ rdrs) n subs + | any isNothing mb_names = [] + | otherwise = n : catMaybes mb_names + where + env = mkOccEnv [(nameOccName s, s) | s <- subNames subs n] + mb_names = map (lookupOccEnv env . rdrNameOcc) rdrs + +subNames :: NameEnv [Name] -> Name -> [Name] +subNames env n = lookupNameEnv env n `orElse` [] +mkSubNameEnv :: NameSet -> NameEnv [Name] +-- Maps types and classes to their constructors/classops respectively +-- This mapping just makes it easier to deal with A(..) export items +mkSubNameEnv names + = foldNameSet add_name emptyNameEnv names + where + add_name name env + | Just parent <- nameParent_maybe name + = extendNameEnv_C (\ns _ -> name:ns) env parent [name] + | otherwise = env ------------------------------- inScopeUnqual :: GlobalRdrEnv -> Name -> Bool @@ -692,10 +664,13 @@ inScopeUnqual env n = any unQualOK (lookupGRE_Name env n) ------------------------------- checkForDodgyExport :: IE RdrName -> [Name] -> RnM () -checkForDodgyExport (IEThingAll tc) [n] = addWarn (dodgyExportWarn tc) - -- This occurs when you import T(..), but - -- only export T abstractly. The single [n] - -- in the AvailTC is the type or class itself +checkForDodgyExport ie@(IEThingAll tc) [n] + | isTcOcc (nameOccName n) = addWarn (dodgyExportWarn tc) + -- This occurs when you export T(..), but + -- only import T abstractly, or T is a synonym. + -- The single [n] is the type or class itself + | otherwise = addErr (exportItemErr ie) + -- This happes if you export x(..), which is bogus checkForDodgyExport _ _ = return () ------------------------------- @@ -787,8 +762,9 @@ gre_is_used used_names gre = gre_name gre `elemNameSet` used_names %********************************************************* \begin{code} -reportUnusedNames :: TcGblEnv -> RnM () -reportUnusedNames gbl_env +reportUnusedNames :: Maybe [Located (IE RdrName)] -- Export list + -> TcGblEnv -> RnM () +reportUnusedNames export_decls gbl_env = do { warnUnusedTopBinds unused_locals ; warnUnusedModules unused_imp_mods ; warnUnusedImports unused_imports @@ -838,8 +814,10 @@ reportUnusedNames gbl_env -- To figure out the minimal set of imports, start with the things -- that are in scope (i.e. in gbl_env). Then just combine them -- into a bunch of avails, so they are properly grouped + -- + -- BUG WARNING: this does not deal properly with qualified imports! minimal_imports :: FiniteMap Module AvailEnv - minimal_imports0 = emptyFM + minimal_imports0 = foldr add_expall emptyFM expall_mods minimal_imports1 = foldr add_name minimal_imports0 defined_and_used minimal_imports = foldr add_inst_mod minimal_imports1 direct_import_mods -- The last line makes sure that we retain all direct imports @@ -866,6 +844,27 @@ reportUnusedNames gbl_env add_name other acc = acc + -- Modules mentioned as 'module M' in the export list + expall_mods = case export_decls of + Nothing -> [] + Just es -> [m | L _ (IEModuleContents m) <- es] + + -- This is really bogus. The idea is that if we see 'module M' in + -- the export list we must retain the import decls that drive it + -- If we aren't careful we might see + -- module A( module M ) where + -- import M + -- import N + -- and suppose that N exports everything that M does. Then we + -- must not drop the import of M even though N brings it all into + -- scope. + -- + -- BUG WARNING: 'module M' exports aside, what if M.x is mentioned?! + -- + -- The reason that add_expall is bogus is that it doesn't take + -- qualified imports into account. But it's an improvement. + add_expall mod acc = addToFM_C plusAvailEnv acc mod emptyAvailEnv + -- n is the name of the thing, p is the name of its parent mk_avail n (Just p) = AvailTC p [p,n] mk_avail n Nothing | isTcOcc (nameOccName n) = AvailTC n [n] @@ -888,6 +887,9 @@ reportUnusedNames gbl_env -- that are not mentioned in minimal_imports1 -- [Note: not 'minimal_imports', because that includes directly-imported -- modules even if we use nothing from them; see notes above] + -- + -- BUG WARNING: does not deal correctly with multiple imports of the same module + -- becuase direct_import_mods has only one entry per module unused_imp_mods = [(mod,loc) | (mod,imp,loc) <- direct_import_mods, not (mod `elemFM` minimal_imports1), mod /= pRELUDE,