X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Fcompiler%2Frename%2FRnNames.lhs;h=4cdb241d8eee7cdefea308291d06cd95a8ce70b9;hb=9d7da331989abcd1844e9d03b8d1e4163796fa85;hp=8773732c6ddb16e406b9ec2872ce42503d1414cc;hpb=3e12bb2d764b45563000ab3074dac61d22853321;p=ghc-hetmet.git diff --git a/ghc/compiler/rename/RnNames.lhs b/ghc/compiler/rename/RnNames.lhs index 8773732..4cdb241 100644 --- a/ghc/compiler/rename/RnNames.lhs +++ b/ghc/compiler/rename/RnNames.lhs @@ -6,37 +6,40 @@ \begin{code} module RnNames ( rnImports, importsFromLocalDecls, + rnExports, + getLocalDeclBinders, extendRdrEnvRn, reportUnusedNames, reportDeprecations, - mkModDeps, exportsToAvails, exportsFromAvail + mkModDeps ) where #include "HsVersions.h" -import CmdLineOpts ( DynFlag(..) ) +import DynFlags ( DynFlag(..), GhcMode(..) ) import HsSyn ( IE(..), ieName, ImportDecl(..), LImportDecl, - ForeignDecl(..), HsGroup(..), HsBindGroup(..), - Sig(..), collectGroupBinders, tyClDeclNames + ForeignDecl(..), HsGroup(..), HsValBinds(..), + Sig(..), collectHsBindLocatedBinders, tyClDeclNames ) import RnEnv -import IfaceEnv ( lookupOrig, newGlobalBinder ) +import IfaceEnv ( ifaceExportNames ) import LoadIface ( loadSrcInterface ) import TcRnMonad import FiniteMap import PrelNames ( pRELUDE, isUnboundName, main_RDR_Unqual ) -import Module ( Module, moduleUserString, - unitModuleEnv, unitModuleEnv, +import Module ( Module, moduleString, unitModuleEnv, 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, GhciMode(..), - IfaceExport, HomePackageTable, PackageIfaceTable, - availNames, unQualInScope, +import OccName ( srcDataName, isTcOcc, pprNonVarNameSpace, + occNameSpace, + OccEnv, mkOccEnv, lookupOccEnv, emptyOccEnv, + extendOccEnv ) +import HscTypes ( GenAvailInfo(..), AvailInfo, + HomePackageTable, PackageIfaceTable, + unQualInScope, Deprecs(..), ModIface(..), Dependencies(..), lookupIface, ExternalPackageState(..) ) @@ -44,16 +47,16 @@ import Packages ( PackageIdH(..) ) import RdrName ( RdrName, rdrNameOcc, setRdrNameSpace, GlobalRdrEnv, mkGlobalRdrEnv, GlobalRdrElt(..), emptyGlobalRdrEnv, plusGlobalRdrEnv, globalRdrEnvElts, - unQualOK, lookupGRE_Name, - Provenance(..), ImportSpec(..), - isLocalGRE, pprNameProvenance ) + extendGlobalRdrEnv, lookupGlobalRdrEnv, unQualOK, lookupGRE_Name, + Provenance(..), ImportSpec(..), ImpDeclSpec(..), ImpItemSpec(..), + importSpecLoc, importSpecModule, isLocalGRE, pprNameProvenance ) import Outputable import Maybes ( isNothing, catMaybes, mapCatMaybes, seqMaybe, orElse ) -import SrcLoc ( noSrcLoc, Located(..), mkGeneralSrcSpan, - unLoc, noLoc, srcLocSpan, combineSrcSpans, SrcSpan ) +import SrcLoc ( Located(..), mkGeneralSrcSpan, + unLoc, noLoc, srcLocSpan, SrcSpan ) import BasicTypes ( DeprecTxt ) -import ListSetOps ( removeDups ) -import Util ( sortLe, notNull, isSingleton ) +import DriverPhases ( isHsBoot ) +import Util ( notNull ) import List ( partition ) import IO ( openFile, IOMode(..) ) \end{code} @@ -180,11 +183,11 @@ importsFromImportDecl this_mod qual_mod_name = case as_mod of Nothing -> imp_mod_name Just another_name -> another_name - imp_spec = ImportSpec { is_mod = imp_mod_name, is_qual = qual_only, - is_loc = loc, is_as = qual_mod_name } + imp_spec = ImpDeclSpec { is_mod = imp_mod_name, is_qual = qual_only, + is_dloc = 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 -> + ifaceExportNames filtered_exports `thenM` \ total_avails -> filterImports iface imp_spec imp_details total_avails `thenM` \ (avail_env, gbl_env) -> @@ -220,11 +223,10 @@ importsFromImportDecl this_mod ASSERT2( not (pkg `elem` dep_pkgs deps), ppr pkg <+> ppr (dep_pkgs deps) ) ([], pkg : dep_pkgs deps) + -- True <=> import M () import_all = case imp_details of - Just (is_hiding, ls) -- Imports are spec'd explicitly - | not is_hiding -> Just (not (null ls)) - _ -> Nothing -- Everything is imported, - -- (or almost everything [hiding]) + Just (is_hiding, ls) -> not is_hiding && null ls + other -> False -- unqual_avails is the Avails that are visible in *unqualified* form -- We need to know this so we know what to export when we see @@ -247,40 +249,6 @@ importsFromImportDecl this_mod returnM (gbl_env, imports) -exportsToAvails :: [IfaceExport] -> TcRnIf gbl lcl NameSet -exportsToAvails exports - = foldlM do_one emptyNameSet exports - where - 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 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, - -- even though we aren't at the binding site of A.T - -- And it's important, because we may simply re-export A.T - -- without ever sucking in the declaration itself. - warnRedundantSourceImport mod_name = ptext SLIT("Unnecessary {- SOURCE -} in the import of module") <+> quotes (ppr mod_name) @@ -301,32 +269,14 @@ created by its bindings. Complain about duplicate bindings \begin{code} -importsFromLocalDecls :: HsGroup RdrName - -> RnM (GlobalRdrEnv, ImportAvails) +importsFromLocalDecls :: HsGroup RdrName -> RnM TcGblEnv importsFromLocalDecls group - = getModule `thenM` \ this_mod -> - getLocalDeclBinders this_mod group `thenM` \ avails -> - -- The avails that are returned don't include the "system" names - let - all_names :: [Name] -- All the defns; no dups eliminated - all_names = [name | avail <- avails, name <- availNames avail] - - dups :: [[Name]] - (_, dups) = removeDups compare all_names - in - -- Check for duplicate definitions - -- The complaint will come out as "Multiple declarations of Foo.f" because - -- since 'f' is in the env twice, the unQualInScope used by the error-msg - -- printer returns False. It seems awkward to fix, unfortunately. - mappM_ addDupDeclErr dups `thenM_` + = do { gbl_env <- getGblEnv - doptM Opt_ImplicitPrelude `thenM` \ implicit_prelude -> - let - prov = LocalDef this_mod - gbl_env = mkGlobalRdrEnv gres - gres = [ GRE { gre_name = name, gre_prov = prov} - | name <- all_names] + ; names <- getLocalDeclBinders gbl_env group + ; implicit_prelude <- doptM Opt_ImplicitPrelude + ; let { -- Optimisation: filter out names for built-in syntax -- They just clutter up the environment (esp tuples), and the parser -- will generate Exact RdrNames for them, so the cluttered @@ -345,63 +295,72 @@ importsFromLocalDecls group -- 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 - - imports = emptyImportAvails { - imp_env = unitModuleEnv this_mod $ - mkNameSet filtered_names - } - in - returnM (gbl_env, imports) + filtered_names + | implicit_prelude = names + | otherwise = filter (not . isBuiltInSyntax) names ; + + ; this_mod = tcg_mod gbl_env + ; imports = emptyImportAvails { + imp_env = unitModuleEnv this_mod $ + mkNameSet filtered_names + } + } + + ; rdr_env' <- extendRdrEnvRn (tcg_rdr_env gbl_env) names + + ; returnM (gbl_env { tcg_rdr_env = rdr_env', + tcg_imports = imports `plusImportAvails` tcg_imports gbl_env }) + } + +extendRdrEnvRn :: GlobalRdrEnv -> [Name] -> RnM GlobalRdrEnv +-- Add the new locally-bound names one by one, checking for duplicates as +-- we do so. Remember that in Template Haskell the duplicates +-- might *already be* in the GlobalRdrEnv from higher up the module +extendRdrEnvRn rdr_env names + = foldlM add_local rdr_env names + where + add_local rdr_env name + | gres <- lookupGlobalRdrEnv rdr_env (nameOccName name) + , (dup_gre:_) <- filter isLocalGRE gres -- Check for existing *local* defns + = do { addDupDeclErr (gre_name dup_gre) name + ; return rdr_env } + | otherwise + = return (extendGlobalRdrEnv rdr_env new_gre) + where + new_gre = GRE {gre_name = name, gre_prov = LocalDef} \end{code} - -%********************************************************* -%* * -\subsection{Getting binders out of a declaration} -%* * -%********************************************************* - @getLocalDeclBinders@ returns the names for an @HsDecl@. It's used for source code. *** See "THE NAMING STORY" in HsDecls **** \begin{code} -getLocalDeclBinders :: Module -> HsGroup RdrName -> RnM [AvailInfo] -getLocalDeclBinders mod (HsGroup {hs_valds = val_decls, - hs_tyclds = tycl_decls, - hs_fords = foreign_decls }) - = -- For type and class decls, we generate Global names, with - -- no export indicator. They need to be global because they get - -- permanently bound into the TyCons and Classes. They don't need - -- an export indicator because they are all implicitly exported. - - mappM new_tc tycl_decls `thenM` \ tc_avails -> - +getLocalDeclBinders :: TcGblEnv -> HsGroup RdrName -> RnM [Name] +getLocalDeclBinders gbl_env (HsGroup {hs_valds = ValBindsIn val_decls val_sigs, + hs_tyclds = tycl_decls, + hs_fords = foreign_decls }) + = do { tc_names_s <- mappM new_tc tycl_decls + ; val_names <- mappM new_simple val_bndrs + ; return (foldr (++) val_names tc_names_s) } + where + mod = tcg_mod gbl_env + is_hs_boot = isHsBoot (tcg_src gbl_env) ; + val_bndrs | is_hs_boot = sig_hs_bndrs + | otherwise = for_hs_bndrs ++ val_hs_bndrs -- 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 -> + -- *signatures*, and there should be no foreign binders - returnM (tc_avails ++ map Avail names) - where 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 + sig_hs_bndrs = [nm | L _ (TypeSig nm _) <- val_sigs] + val_hs_bndrs = collectHsBindLocatedBinders val_decls for_hs_bndrs = [nm | L _ (ForeignImport nm _ _ _) <- foreign_decls] new_tc tc_decl - = newTopSrcBinder mod Nothing main_rdr `thenM` \ main_name -> - mappM (newTopSrcBinder mod (Just main_name)) sub_rdrs `thenM` \ sub_names -> - returnM (AvailTC main_name (main_name : sub_names)) + = do { main_name <- newTopSrcBinder mod Nothing main_rdr + ; sub_names <- mappM (newTopSrcBinder mod (Just main_name)) sub_rdrs + ; return (main_name : sub_names) } where (main_rdr : sub_rdrs) = tyClDeclNames (unLoc tc_decl) \end{code} @@ -418,7 +377,7 @@ available, and filters it through the import spec (if any). \begin{code} filterImports :: ModIface - -> ImportSpec -- The span for the entire import decl + -> ImpDeclSpec -- The span for the entire import decl -> Maybe (Bool, [Located (IE RdrName)]) -- Import spec; True => hiding -> NameSet -- What's available -> RnM (NameSet, -- What's imported (qualified or unqualified) @@ -427,14 +386,16 @@ filterImports :: ModIface -- Complains if import spec mentions things that the module doesn't export -- Warns/informs if import spec contains duplicates. -mkGenericRdrEnv imp_spec names - = mkGlobalRdrEnv [ GRE { gre_name = name, gre_prov = Imported [imp_spec] False } +mkGenericRdrEnv decl_spec names + = mkGlobalRdrEnv [ GRE { gre_name = name, gre_prov = Imported [imp_spec] } | name <- nameSetToList names ] + where + imp_spec = ImpSpec { is_decl = decl_spec, is_item = ImpAll } -filterImports iface imp_spec Nothing all_names - = returnM (all_names, mkGenericRdrEnv imp_spec all_names) +filterImports iface decl_spec Nothing all_names + = returnM (all_names, mkGenericRdrEnv decl_spec all_names) -filterImports iface imp_spec (Just (want_hiding, import_items)) all_names +filterImports iface decl_spec (Just (want_hiding, import_items)) all_names = mappM (addLocM get_item) import_items `thenM` \ gres_s -> let gres = concat gres_s @@ -447,7 +408,7 @@ filterImports iface imp_spec (Just (want_hiding, import_items)) all_names keep n = not (n `elemNameSet` specified_names) pruned_avails = filterNameSet keep all_names in - return (pruned_avails, mkGenericRdrEnv imp_spec pruned_avails) + return (pruned_avails, mkGenericRdrEnv decl_spec pruned_avails) where occ_env :: OccEnv Name -- Maps OccName to corresponding Name @@ -459,7 +420,7 @@ filterImports iface imp_spec (Just (want_hiding, import_items)) all_names sub_env :: NameEnv [Name] sub_env = mkSubNameEnv all_names - bale_out item = addErr (badImportItemErr iface imp_spec item) `thenM_` + bale_out item = addErr (badImportItemErr iface decl_spec item) `thenM_` returnM [] succeed_with :: Bool -> [Name] -> RnM [GlobalRdrElt] @@ -468,9 +429,11 @@ filterImports iface imp_spec (Just (want_hiding, import_items)) all_names ; 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 || isNothing (nameParent_maybe name) + gre_prov = Imported [imp_spec] } + where + imp_spec = ImpSpec { is_decl = decl_spec, is_item = item_spec } + item_spec = ImpSome { is_explicit = explicit, is_iloc = loc } + explicit = all_explicit || isNothing (nameParent_maybe name) get_item :: IE RdrName -> RnM [GlobalRdrElt] -- Empty result for a bad item. @@ -495,7 +458,7 @@ filterImports iface imp_spec (Just (want_hiding, import_items)) all_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 + -- *or* a type/class, or even both = case concat [check_item item, check_item (IEVar data_n)] of [] -> bale_out item names -> succeed_with True names @@ -535,7 +498,7 @@ it re-exports @GHC@, which includes @takeMVar#@, whose type includes \begin{code} type ExportAccum -- The type of the accumulating parameter of - -- the main worker function in exportsFromAvail + -- the main worker function in rnExports = ([Module], -- 'module M's seen so far ExportOccMap, -- Tracks exported occurrence names NameSet) -- The accumulated exported stuff @@ -548,14 +511,14 @@ type ExportOccMap = OccEnv (Name, IE RdrName) -- that have the same occurrence name -exportsFromAvail :: Bool -- False => no 'module M(..) where' header at all - -> Maybe [Located (IE RdrName)] -- Nothing => no explicit export list - -> RnM NameSet +rnExports :: Bool -- False => no 'module M(..) where' header at all + -> Maybe [Located (IE RdrName)] -- Nothing => no explicit export list + -> RnM NameSet -- Complains if two distinct exports have same OccName -- Warns about identical exports. -- Complains about exports items not in scope -exportsFromAvail explicit_mod exports +rnExports explicit_mod exports = do { TcGblEnv { tcg_rdr_env = rdr_env, tcg_imports = imports } <- getGblEnv ; @@ -570,6 +533,7 @@ exportsFromAvail explicit_mod exports | explicit_mod = exports | ghci_mode == Interactive = Nothing | otherwise = Just [noLoc (IEVar main_RDR_Unqual)] } ; + -- ToDo: the 'noLoc' here is unhelpful if 'main' turns out to be out of scope exports_from_avail real_exports rdr_env imports } @@ -641,6 +605,7 @@ filterAvail (IEThingWith _ rdrs) n subs where env = mkOccEnv [(nameOccName s, s) | s <- subNames subs n] mb_names = map (lookupOccEnv env . rdrNameOcc) rdrs +filterAvail (IEModuleContents _) _ _ = panic "filterAvail" subNames :: NameEnv [Name] -> Name -> [Name] subNames env n = lookupNameEnv env n `orElse` [] @@ -707,23 +672,26 @@ reportDeprecations :: TcGblEnv -> RnM () reportDeprecations tcg_env = ifOptM Opt_WarnDeprecations $ do { (eps,hpt) <- getEpsAndHpt + -- By this time, typechecking is complete, + -- so the PIT is fully populated ; mapM_ (check hpt (eps_PIT eps)) all_gres } where - used_names = findUses (tcg_dus tcg_env) emptyNameSet + used_names = allUses (tcg_dus tcg_env) + -- Report on all deprecated uses; hence allUses all_gres = globalRdrEnvElts (tcg_rdr_env tcg_env) - check hpt pit (GRE {gre_name = name, gre_prov = Imported (imp_spec:_) _}) + check hpt pit (GRE {gre_name = name, gre_prov = Imported (imp_spec:_)}) | name `elemNameSet` used_names , Just deprec_txt <- lookupDeprec hpt pit name - = setSrcSpan (is_loc imp_spec) $ + = setSrcSpan (importSpecLoc imp_spec) $ addWarn (sep [ptext SLIT("Deprecated use of") <+> - occNameFlavour (nameOccName name) <+> + pprNonVarNameSpace (occNameSpace (nameOccName name)) <+> quotes (ppr name), - (parens imp_msg), + (parens imp_msg) <> colon, (ppr deprec_txt) ]) where name_mod = nameModule name - imp_mod = is_mod imp_spec + imp_mod = importSpecModule imp_spec imp_msg = ptext SLIT("imported from") <+> ppr imp_mod <> extra extra | imp_mod == name_mod = empty | otherwise = ptext SLIT(", but defined in") <+> ppr name_mod @@ -765,14 +733,18 @@ gre_is_used used_names gre = gre_name gre `elemNameSet` used_names reportUnusedNames :: Maybe [Located (IE RdrName)] -- Export list -> TcGblEnv -> RnM () reportUnusedNames export_decls gbl_env - = do { warnUnusedTopBinds unused_locals + = do { traceRn ((text "RUN") <+> (ppr (tcg_dus gbl_env))) + ; warnUnusedTopBinds unused_locals ; warnUnusedModules unused_imp_mods ; warnUnusedImports unused_imports - ; warnDuplicateImports dup_imps + ; warnDuplicateImports defined_and_used ; printMinimalImports minimal_imports } where used_names, all_used_names :: NameSet used_names = findUses (tcg_dus gbl_env) emptyNameSet + -- NB: currently, if f x = g, we only treat 'g' as used if 'f' is used + -- Hence findUses + all_used_names = used_names `unionNameSets` mkNameSet (mapCatMaybes nameParent_maybe (nameSetToList used_names)) -- A use of C implies a use of T, @@ -789,11 +761,6 @@ reportUnusedNames export_decls gbl_env (defined_and_used, defined_but_not_used) = partition (gre_is_used all_used_names) defined_names - -- Find the duplicate imports - dup_imps = filter is_dup defined_and_used - is_dup (GRE {gre_prov = Imported imp_spec True}) = not (isSingleton imp_spec) - is_dup other = False - -- Filter out the ones that are -- (a) defined in this module, and -- (b) not defined by a 'deriving' clause @@ -805,8 +772,9 @@ reportUnusedNames export_decls gbl_env unused_imports :: [GlobalRdrElt] unused_imports = filter unused_imp defined_but_not_used - unused_imp (GRE {gre_prov = Imported imp_specs True}) - = not (all (module_unused . is_mod) imp_specs) + unused_imp (GRE {gre_prov = Imported imp_specs}) + = not (all (module_unused . importSpecModule) imp_specs) + && or [exp | ImpSpec { is_item = ImpSome { is_explicit = exp } } <- imp_specs] -- Don't complain about unused imports if we've already said the -- entire import is unused unused_imp other = False @@ -838,8 +806,8 @@ reportUnusedNames export_decls gbl_env -- We've carefully preserved the provenance so that we can -- construct minimal imports that import the name by (one of) -- the same route(s) as the programmer originally did. - add_name (GRE {gre_name = n, gre_prov = Imported imp_specs _}) acc - = addToFM_C plusAvailEnv acc (is_mod (head imp_specs)) + add_name (GRE {gre_name = n, gre_prov = Imported imp_specs}) acc + = addToFM_C plusAvailEnv acc (importSpecModule (head imp_specs)) (unitAvailEnv (mk_avail n (nameParent_maybe n))) add_name other acc = acc @@ -879,7 +847,7 @@ reportUnusedNames export_decls gbl_env imports = tcg_imports gbl_env - direct_import_mods :: [(Module, Maybe Bool, SrcSpan)] + direct_import_mods :: [(Module, Bool, SrcSpan)] -- See the type of the imp_mods for this triple direct_import_mods = moduleEnvElts (imp_mods imports) @@ -890,11 +858,11 @@ reportUnusedNames export_decls gbl_env -- -- 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, + unused_imp_mods = [(mod,loc) | (mod,no_imp,loc) <- direct_import_mods, not (mod `elemFM` minimal_imports1), mod /= pRELUDE, - imp /= Just False] - -- The Just False part is not to complain about + not no_imp] + -- The not no_imp part is not to complain about -- import M (), which is an idiom for importing -- instance declarations @@ -903,13 +871,80 @@ reportUnusedNames export_decls gbl_env --------------------- warnDuplicateImports :: [GlobalRdrElt] -> RnM () +-- Given the GREs for names that are used, figure out which imports +-- could be omitted without changing the top-level environment. +-- +-- NB: Given import Foo( T ) +-- import qualified Foo +-- we do not report a duplicate import, even though Foo.T is brought +-- into scope by both, because there's nothing you can *omit* without +-- changing the top-level environment. So we complain only if it's +-- explicitly named in both imports or neither. +-- +-- Furthermore, we complain about Foo.T only if +-- there is no complaint about (unqualified) T + warnDuplicateImports gres - = ifOptM Opt_WarnUnusedImports (mapM_ warn gres) + = ifOptM Opt_WarnUnusedImports $ + sequenceM_ [ warn name pr + -- The 'head' picks the first offending group + -- for this particular name + | GRE { gre_name = name, gre_prov = Imported imps } <- gres + , pr <- redundants imps ] where - warn (GRE { gre_name = name, gre_prov = Imported imps _ }) - = addWarn ((quotes (ppr name) <+> ptext SLIT("is imported more than once:")) - $$ nest 2 (vcat (map ppr imps))) - + warn name (red_imp, cov_imp) + = addWarnAt (importSpecLoc red_imp) + (vcat [ptext SLIT("Redundant import of:") <+> quotes pp_name, + ptext SLIT("It is also") <+> ppr cov_imp]) + where + pp_name | is_qual red_decl = ppr (is_as red_decl) <> dot <> ppr occ + | otherwise = ppr occ + occ = nameOccName name + red_decl = is_decl red_imp + + redundants :: [ImportSpec] -> [(ImportSpec,ImportSpec)] + -- The returned pair is (redundant-import, covering-import) + redundants imps + = [ (red_imp, cov_imp) + | red_imp <- imps + , cov_imp <- take 1 (filter (covers red_imp) imps) ] + + -- "red_imp" is a putative redundant import + -- "cov_imp" potentially covers it + -- This test decides whether red_imp could be dropped + -- + -- NOTE: currently the test does not warn about + -- import M( x ) + -- imoprt N( x ) + -- even if the same underlying 'x' is involved, because dropping + -- either import would change the qualified names in scope (M.x, N.x) + -- But if the qualified names aren't used, the import is indeed redundant + -- Sadly we don't know that. Oh well. + covers red_imp@(ImpSpec { is_decl = red_decl, is_item = red_item }) + cov_imp@(ImpSpec { is_decl = cov_decl, is_item = cov_item }) + | red_loc == cov_loc + = False -- Ignore diagonal elements + | not (is_as red_decl == is_as cov_decl) + = False -- They bring into scope different qualified names + | not (is_qual red_decl) && is_qual cov_decl + = False -- Covering one doesn't bring unqualified name into scope + | red_selective + = not cov_selective -- Redundant one is selective and covering one isn't + || red_later -- Both are explicit; tie-break using red_later + | otherwise + = not cov_selective -- Neither import is selective + && (is_mod red_decl == is_mod cov_decl) -- They import the same module + && red_later -- Tie-break + where + red_loc = importSpecLoc red_imp + cov_loc = importSpecLoc cov_imp + red_later = red_loc > cov_loc + cov_selective = selectiveImpItem cov_item + red_selective = selectiveImpItem red_item + +selectiveImpItem :: ImpItemSpec -> Bool +selectiveImpItem ImpAll = False +selectiveImpItem (ImpSome {}) = True -- ToDo: deal with original imports with 'qualified' and 'as M' clauses printMinimalImports :: FiniteMap Module AvailEnv -- Minimal imports @@ -925,7 +960,7 @@ printMinimalImports imps (vcat (map ppr_mod_ie mod_ies)) }) } where - mkFilename this_mod = moduleUserString this_mod ++ ".imports" + mkFilename this_mod = moduleString this_mod ++ ".imports" ppr_mod_ie (mod_name, ies) | mod_name == pRELUDE = empty @@ -969,8 +1004,8 @@ printMinimalImports imps %************************************************************************ \begin{code} -badImportItemErr iface imp_spec ie - = sep [ptext SLIT("Module"), quotes (ppr (is_mod imp_spec)), source_import, +badImportItemErr iface decl_spec ie + = sep [ptext SLIT("Module"), quotes (ppr (is_mod decl_spec)), source_import, ptext SLIT("does not export"), quotes (ppr ie)] where source_import | mi_boot iface = ptext SLIT("(hi-boot interface)") @@ -1006,16 +1041,16 @@ exportClashErr global_env name1 name2 ie1 ie2 (gre:_) -> gre [] -> pprPanic "exportClashErr" (ppr name) -addDupDeclErr :: [Name] -> TcRn () -addDupDeclErr names - = addErrAt big_loc $ +addDupDeclErr :: Name -> Name -> TcRn () +addDupDeclErr name_a name_b + = addErrAt (srcLocSpan loc2) $ vcat [ptext SLIT("Multiple declarations of") <+> quotes (ppr name1), - ptext SLIT("Declared at:") <+> vcat (map ppr sorted_locs)] + ptext SLIT("Declared at:") <+> vcat [ppr (nameSrcLoc name1), ppr loc2]] where - locs = map nameSrcLoc names - big_loc = foldr1 combineSrcSpans (map srcLocSpan locs) - name1 = head names - sorted_locs = sortLe (<=) (sortLe (<=) locs) + loc2 = nameSrcLoc name2 + (name1,name2) | nameSrcLoc name_a > nameSrcLoc name_b = (name_b,name_a) + | otherwise = (name_a,name_b) + -- Report the error at the later location dupExportWarn occ_name ie1 ie2 = hsep [quotes (ppr occ_name),