X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Fcompiler%2Frename%2FRnNames.lhs;h=0af917b264cbb6deb223cb3ccca892581fdbb732;hb=3e12bb2d764b45563000ab3074dac61d22853321;hp=db749a4451528b6a37b5d70d231f7466f012f401;hpb=438596897ebbe25a07e1c82085cfbc5bdb00f09e;p=ghc-hetmet.git diff --git a/ghc/compiler/rename/RnNames.lhs b/ghc/compiler/rename/RnNames.lhs index db749a4..8773732 100644 --- a/ghc/compiler/rename/RnNames.lhs +++ b/ghc/compiler/rename/RnNames.lhs @@ -5,622 +5,963 @@ \begin{code} module RnNames ( - getGlobalNames + rnImports, importsFromLocalDecls, + reportUnusedNames, reportDeprecations, + mkModDeps, exportsToAvails, exportsFromAvail ) where #include "HsVersions.h" -import CmdLineOpts ( opt_NoImplicitPrelude, opt_WarnDuplicateExports, - opt_SourceUnchanged - ) - -import HsSyn ( HsModule(..), ImportDecl(..), HsDecl(..), - IE(..), ieName, - ForeignDecl(..), ExtName(..), ForKind(..), - FixityDecl(..), - collectTopBinders - ) -import RdrHsSyn ( RdrName(..), RdrNameIE, RdrNameImportDecl, - RdrNameHsModule, RdrNameFixityDecl, - rdrNameOcc, ieOcc - ) -import RnIfaces ( getInterfaceExports, getDeclBinders, recordSlurp, checkUpToDate ) -import BasicTypes ( IfaceFlavour(..) ) +import CmdLineOpts ( DynFlag(..) ) +import HsSyn ( IE(..), ieName, ImportDecl(..), LImportDecl, + ForeignDecl(..), HsGroup(..), HsBindGroup(..), + Sig(..), collectGroupBinders, tyClDeclNames + ) import RnEnv -import RnMonad +import IfaceEnv ( lookupOrig, newGlobalBinder ) +import LoadIface ( loadSrcInterface ) +import TcRnMonad import FiniteMap -import PrelMods -import UniqFM ( lookupUFM ) -import Bag ( bagToList ) -import Maybes ( maybeToBool ) -import Name -import NameSet ( elemNameSet ) +import PrelNames ( pRELUDE, isUnboundName, main_RDR_Unqual ) +import Module ( Module, moduleUserString, + unitModuleEnv, 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, + Deprecs(..), ModIface(..), Dependencies(..), + lookupIface, ExternalPackageState(..) + ) +import Packages ( PackageIdH(..) ) +import RdrName ( RdrName, rdrNameOcc, setRdrNameSpace, + GlobalRdrEnv, mkGlobalRdrEnv, GlobalRdrElt(..), + emptyGlobalRdrEnv, plusGlobalRdrEnv, globalRdrEnvElts, + unQualOK, lookupGRE_Name, + Provenance(..), ImportSpec(..), + isLocalGRE, pprNameProvenance ) import Outputable -import Util ( removeDups ) +import Maybes ( isNothing, catMaybes, mapCatMaybes, seqMaybe, orElse ) +import SrcLoc ( noSrcLoc, Located(..), mkGeneralSrcSpan, + unLoc, noLoc, srcLocSpan, combineSrcSpans, SrcSpan ) +import BasicTypes ( DeprecTxt ) +import ListSetOps ( removeDups ) +import Util ( sortLe, notNull, isSingleton ) +import List ( partition ) +import IO ( openFile, IOMode(..) ) \end{code} %************************************************************************ %* * -\subsection{Get global names} + rnImports %* * %************************************************************************ \begin{code} -getGlobalNames :: RdrNameHsModule - -> RnMG (Maybe (ExportEnv, - RnEnv, - FiniteMap Name HowInScope, -- Locally defined or explicitly imported - Name -> PrintUnqualified)) - -- Nothing => no need to recompile - -getGlobalNames m@(HsModule this_mod _ exports imports _ _ mod_loc) - = fixRn (\ ~(rec_exp_fn, _) -> - - -- PROCESS LOCAL DECLS - -- Do these *first* so that the correct provenance gets - -- into the global name cache. - importsFromLocalDecls rec_exp_fn m `thenRn` \ (local_rn_env, local_mod_avails, local_info) -> - - -- PROCESS IMPORT DECLS - mapAndUnzip3Rn importsFromImportDecl all_imports - `thenRn` \ (imp_rn_envs, imp_avails_s, explicit_imports_s) -> - - -- COMBINE RESULTS - -- We put the local env second, so that a local provenance - -- "wins", even if a module imports itself. - foldlRn plusRnEnv emptyRnEnv imp_rn_envs `thenRn` \ imp_rn_env -> - plusRnEnv imp_rn_env local_rn_env `thenRn` \ rn_env -> - - -- TRY FOR EARLY EXIT - -- We can't go for an early exit before this because we have to check - -- for name clashes. Consider: - -- - -- module A where module B where - -- import B h = True - -- f = h - -- - -- Suppose I've compiled everything up, and then I add a - -- new definition to module B, that defines "f". - -- - -- Then I must detect the name clash in A before going for an early - -- exit. The early-exit code checks what's actually needed from B - -- to compile A, and of course that doesn't include B.f. That's - -- why we wait till after the plusRnEnv stuff to do the early-exit. - checkEarlyExit this_mod `thenRn` \ up_to_date -> - if up_to_date then - returnRn (error "early exit", Nothing) - else - - - -- PROCESS EXPORT LISTS - let - export_avails :: ExportAvails - export_avails = foldr plusExportAvails local_mod_avails imp_avails_s - - explicit_info :: FiniteMap Name HowInScope -- Locally defined or explicitly imported - explicit_info = foldr plusFM local_info explicit_imports_s - in - exportsFromAvail this_mod exports export_avails rn_env - `thenRn` \ (export_fn, export_env) -> - - -- BUILD THE "IMPORT FN". It just tells whether a name is in - -- scope in an unqualified form. - let - print_unqual = mkImportFn imp_rn_env - in - - returnRn (export_fn, Just (export_env, rn_env, explicit_info, print_unqual)) - ) `thenRn` \ (_, result) -> - returnRn result +rnImports :: [LImportDecl RdrName] + -> RnM (GlobalRdrEnv, ImportAvails) + +rnImports imports + = do { -- PROCESS IMPORT DECLS + -- Do the non {- SOURCE -} ones first, so that we get a helpful + -- warning for {- SOURCE -} ones that are unnecessary + this_mod <- getModule + ; implicit_prelude <- doptM Opt_ImplicitPrelude + ; let + 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 + + get_imports = importsFromImportDecl this_mod + + ; stuff1 <- mappM get_imports ordinary + ; stuff2 <- mappM get_imports source + + -- COMBINE RESULTS + ; let + (imp_gbl_envs, imp_avails) = unzip (stuff1 ++ stuff2) + gbl_env :: GlobalRdrEnv + gbl_env = foldr plusGlobalRdrEnv emptyGlobalRdrEnv imp_gbl_envs + + all_avails :: ImportAvails + all_avails = foldr plusImportAvails emptyImportAvails imp_avails + + -- ALL DONE + ; return (gbl_env, all_avails) } where - junk_exp_fn = error "RnNames:export_fn" + -- 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 implicit_prelude + | this_mod == pRELUDE + || explicit_prelude_import + || not implicit_prelude + = [] - all_imports = prel_imports ++ imports + | otherwise = [preludeImportDecl] - -- 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. - prel_imports | this_mod == pRELUDE || - explicit_prelude_import || - opt_NoImplicitPrelude - = [] - - | otherwise = [ImportDecl pRELUDE - False {- Not qualified -} - HiFile {- Not source imported -} - Nothing {- No "as" -} - Nothing {- No import list -} - mod_loc] - explicit_prelude_import - = not (null [ () | (ImportDecl mod qual _ _ _ _) <- imports, mod == pRELUDE ]) + = notNull [ () | L _ (ImportDecl mod _ _ _ _) <- imports, + unLoc mod == pRELUDE ] + +preludeImportDecl + = L loc $ + ImportDecl (L loc pRELUDE) + False {- Not a boot interface -} + False {- Not qualified -} + Nothing {- No "as" -} + Nothing {- No import list -} + where + loc = mkGeneralSrcSpan FSLIT("Implicit import declaration") \end{code} \begin{code} -checkEarlyExit mod - = checkErrsRn `thenRn` \ no_errs_so_far -> - if not no_errs_so_far then - -- Found errors already, so exit now - returnRn True - else +importsFromImportDecl :: Module + -> LImportDecl RdrName + -> RnM (GlobalRdrEnv, ImportAvails) - traceRn (text "Considering whether compilation is required...") `thenRn_` - if not opt_SourceUnchanged then - -- Source code changed and no errors yet... carry on - traceRn (nest 4 (text "source file changed or recompilation check turned off")) `thenRn_` - returnRn False - else +importsFromImportDecl this_mod + (L loc (ImportDecl loc_imp_mod_name want_boot qual_only as_mod imp_details)) + = + setSrcSpan loc $ - -- Unchanged source, and no errors yet; see if usage info - -- up to date, and exit if so - checkUpToDate mod `thenRn` \ up_to_date -> - putDocRn (text "Compilation" <+> - text (if up_to_date then "IS NOT" else "IS") <+> - text "required") `thenRn_` - returnRn up_to_date -\end{code} - -\begin{code} -importsFromImportDecl :: RdrNameImportDecl - -> RnMG (RnEnv, - ExportAvails, - FiniteMap Name HowInScope) -- Records the explicitly-imported things - -importsFromImportDecl (ImportDecl mod qual_only as_source as_mod import_spec loc) - = pushSrcLocRn loc $ - getInterfaceExports mod as_source `thenRn` \ (avails, fixities) -> - filterImports mod import_spec avails `thenRn` \ (filtered_avails, hides, explicits) -> + -- If there's an error in loadInterface, (e.g. interface + -- file not found) we get lots of spurious errors from 'filterImports' let - how_in_scope = FromImportDecl mod loc - explicit_info = listToFM [(name, how_in_scope) - | avail <- explicits, - name <- availNames avail - ] + imp_mod_name = unLoc loc_imp_mod_name + doc = ppr imp_mod_name <+> ptext SLIT("is directly imported") in - qualifyImports mod - True -- Want qualified names - (not qual_only) -- Maybe want unqualified names - as_mod - hides - filtered_avails (\n -> how_in_scope) - [ (occ,(fixity,how_in_scope)) | (occ,fixity) <- fixities ] - `thenRn` \ (rn_env, mod_avails) -> - returnRn (rn_env, mod_avails, explicit_info) -\end{code} + loadSrcInterface doc imp_mod_name want_boot `thenM` \ iface -> + -- Compiler sanity check: if the import didn't say + -- {-# SOURCE #-} we should not get a hi-boot file + WARN( not want_boot && mi_boot iface, ppr imp_mod_name ) -\begin{code} -importsFromLocalDecls rec_exp_fn (HsModule mod _ _ _ fix_decls decls _) - = foldlRn getLocalDeclBinders [] decls `thenRn` \ avails -> + -- Issue a user warning for a redundant {- SOURCE -} import + -- NB that we arrange to read all the ordinary imports before + -- any of the {- SOURCE -} imports + warnIf (want_boot && not (mi_boot iface)) + (warnRedundantSourceImport imp_mod_name) `thenM_` - -- Record that locally-defined things are available - mapRn (recordSlurp Nothing Compulsory) avails `thenRn_` + let + imp_mod = mi_module iface + deprecs = mi_deprecs iface + is_orph = mi_orphan iface + deps = mi_deps iface + + filtered_exports = filter not_this_mod (mi_exports iface) + not_this_mod (mod,_) = mod /= this_mod + -- If the module exports anything defined in this module, just ignore it. + -- Reason: otherwise it looks as if there are two local definition sites + -- for the thing, and an error gets reported. Easiest thing is just to + -- filter them out up front. This situation only arises if a module + -- imports itself, or another module that imported it. (Necessarily, + -- this invoves a loop.) + -- + -- Tiresome consequence: if you say + -- module A where + -- import B( AType ) + -- type AType = ... + -- + -- module B( AType ) where + -- import {-# SOURCE #-} A( AType ) + -- + -- then you'll get a 'B does not export AType' message. Oh well. + + 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 } + in + -- Get the total imports, and filter them according to the import list + exportsToAvails filtered_exports `thenM` \ total_avails -> + filterImports iface imp_spec + imp_details total_avails `thenM` \ (avail_env, gbl_env) -> - -- Fixities - mapRn fixityFromFixDecl fix_decls `thenRn` \ fixities -> + getDOpts `thenM` \ dflags -> - -- Record where the available stuff came from let - explicit_info = listToFM [(name, FromLocalDefn (getSrcLoc name)) - | avail <- avails, - name <- availNames avail - ] + -- Compute new transitive dependencies + + orphans | is_orph = ASSERT( not (imp_mod_name `elem` dep_orphs deps) ) + imp_mod_name : dep_orphs deps + | otherwise = dep_orphs deps + + (dependent_mods, dependent_pkgs) + = case mi_package iface of + HomePackage -> + -- Imported module is from the home package + -- Take its dependent modules and add imp_mod itself + -- Take its dependent packages unchanged + -- + -- NB: (dep_mods deps) might include a hi-boot file + -- for the module being compiled, CM. Do *not* filter + -- this out (as we used to), because when we've + -- finished dealing with the direct imports we want to + -- know if any of them depended on CM.hi-boot, in + -- which case we should do the hi-boot consistency + -- check. See LoadIface.loadHiBootInterface + ((imp_mod_name, want_boot) : dep_mods deps, dep_pkgs deps) + + ExtPackage pkg -> + -- Imported module is from another package + -- Dump the dependent modules + -- Add the package imp_mod comes from to the dependent packages + ASSERT2( not (pkg `elem` dep_pkgs deps), ppr pkg <+> ppr (dep_pkgs deps) ) + ([], pkg : dep_pkgs deps) + + 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]) + + -- 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 + -- module M ( module P ) where ... + -- Then we must export whatever came from P unqualified. + imports = ImportAvails { + 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, + imp_dep_pkgs = dependent_pkgs } + in - qualifyImports mod - False -- Don't want qualified names - True -- Want unqualified names - Nothing -- No "as M" part - [] -- Hide nothing - avails (\n -> FromLocalDefn (getSrcLoc n)) - fixities - `thenRn` \ (rn_env, mod_avails) -> - returnRn (rn_env, mod_avails, explicit_info) + -- Complain if we import a deprecated module + ifOptM Opt_WarnDeprecations ( + case deprecs of + DeprecAll txt -> addWarn (moduleDeprec imp_mod_name txt) + other -> returnM () + ) `thenM_` + + returnM (gbl_env, imports) + +exportsToAvails :: [IfaceExport] -> TcRnIf gbl lcl NameSet +exportsToAvails exports + = foldlM do_one emptyNameSet exports where - newLocalName rdr_name loc - = newLocallyDefinedGlobalName mod (rdrNameOcc rdr_name) rec_exp_fn loc - - getLocalDeclBinders avails (ValD binds) - = mapRn do_one (bagToList (collectTopBinders binds)) `thenRn` \ val_avails -> - returnRn (val_avails ++ avails) - - -- foreign import declaration - getLocalDeclBinders avails (ForD (ForeignDecl nm (FoImport _) _ _ _ loc)) - = do_one (nm,loc) `thenRn` \ for_avail -> - returnRn (for_avail : avails) - - -- foreign import declaration - getLocalDeclBinders avails (ForD (ForeignDecl nm FoLabel _ _ _ loc)) - = do_one (nm,loc) `thenRn` \ for_avail -> - returnRn (for_avail : avails) - - -- foreign export dynamic declaration - getLocalDeclBinders avails (ForD (ForeignDecl nm FoExport _ Dynamic _ loc)) - = do_one (nm,loc) `thenRn` \ for_avail -> - returnRn (for_avail : avails) - - getLocalDeclBinders avails decl - = getDeclBinders newLocalName decl `thenRn` \ avail -> - case avail of - NotAvailable -> returnRn avails -- Instance decls and suchlike - other -> returnRn (avail : avails) - - do_one (rdr_name, loc) - = newLocalName rdr_name loc `thenRn` \ name -> - returnRn (Avail name) + 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) \end{code} + %************************************************************************ %* * -\subsection{Filtering imports} + importsFromLocalDecls %* * %************************************************************************ -@filterImports@ takes the @ExportEnv@ telling what the imported module makes -available, and filters it through the import spec (if any). +From the top-level declarations of this module produce + * the lexical environment + * the ImportAvails +created by its bindings. + +Complain about duplicate bindings \begin{code} -filterImports :: Module - -> Maybe (Bool, [RdrNameIE]) -- Import spec; True => hidin - -> [AvailInfo] -- What's available - -> RnMG ([AvailInfo], -- What's actually imported - [AvailInfo], -- What's to be hidden (the unqualified version, that is) - [AvailInfo]) -- What was imported explicitly +importsFromLocalDecls :: HsGroup RdrName + -> RnM (GlobalRdrEnv, ImportAvails) +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] - -- Complains if import spec mentions things that the module doesn't export - -- Warns/informs if import spec contains duplicates. -filterImports mod Nothing imports - = returnRn (imports, [], []) - -filterImports mod (Just (want_hiding, import_items)) avails - = mapRn check_item import_items `thenRn` \ item_avails -> - if want_hiding - then - returnRn (avails, item_avails, []) -- All imported; item_avails to be hidden - else - returnRn (item_avails, [], item_avails) -- Just item_avails imported; nothing to be hidden + 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_` - where - import_fm :: FiniteMap OccName AvailInfo - import_fm = listToFM [ (nameOccName name, avail) - | avail <- avails, - name <- availEntityNames avail] - - check_item item@(IEModuleContents _) - = addErrRn (badImportItemErr mod item) `thenRn_` - returnRn NotAvailable - - check_item item - | not (maybeToBool maybe_in_import_avails) || - (case filtered_avail of { NotAvailable -> True; other -> False }) - = addErrRn (badImportItemErr mod item) `thenRn_` - returnRn NotAvailable - - | dodgy_import = addWarnRn (dodgyImportWarn mod item) `thenRn_` - returnRn filtered_avail - - | otherwise = returnRn filtered_avail - - where - maybe_in_import_avails = lookupFM import_fm (ieOcc item) - Just avail = maybe_in_import_avails - filtered_avail = filterAvail item avail - dodgy_import = case (item, avail) of - (IEThingAll _, AvailTC _ [n]) -> True - -- This occurs when you import T(..), but - -- only export T abstractly. The single [n] - -- in the AvailTC is the type or class itself - - other -> False - + 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] + + -- 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 + -- envt is no use. To avoid doing this filter all the time, + -- we use -fno-implicit-prelude as a clue that the filter is + -- worth while. Really, it's only useful for GHC.Base and GHC.Tuple. + -- + -- 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 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 + + imports = emptyImportAvails { + imp_env = unitModuleEnv this_mod $ + mkNameSet filtered_names + } + in + returnM (gbl_env, imports) \end{code} +%********************************************************* +%* * +\subsection{Getting binders out of a declaration} +%* * +%********************************************************* -%************************************************************************ -%* * -\subsection{Qualifiying imports} -%* * -%************************************************************************ +@getLocalDeclBinders@ returns the names for an @HsDecl@. It's +used for source code. -@qualifyImports@ takes the @ExportEnv@ after filtering through the import spec -of an import decl, and deals with producing an @RnEnv@ with the -right qualified names. It also turns the @Names@ in the @ExportEnv@ into -fully fledged @Names@. + *** See "THE NAMING STORY" in HsDecls **** \begin{code} -qualifyImports :: Module -- Imported module - -> Bool -- True <=> want qualified import - -> Bool -- True <=> want unqualified import - -> Maybe Module -- Optional "as M" part - -> [AvailInfo] -- What's to be hidden - -> Avails -> (Name -> HowInScope) -- Whats imported and how - -> [(OccName, (Fixity, HowInScope))] -- Ditto for fixities - -> RnMG (RnEnv, ExportAvails) - -qualifyImports this_mod qual_imp unqual_imp as_mod hides - avails name_to_his fixities - = - -- Make the name environment. Even though we're talking about a - -- single import module there might still be name clashes, - -- because it might be the module being compiled. - foldlRn add_avail emptyGlobalNameEnv avails `thenRn` \ name_env1 -> - let - -- Delete things that are hidden - name_env2 = foldl del_avail name_env1 hides - - -- Create the fixity env - fixity_env = foldl (add_fixity name_env2) emptyFixityEnv fixities - - -- Create the export-availability info - export_avails = mkExportAvails qual_mod unqual_imp name_env2 avails +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 -> + + -- 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 - returnRn (RnEnv name_env2 fixity_env, export_avails) + mappM new_simple val_bndrs `thenM` \ names -> + + returnM (tc_avails ++ map Avail names) where - qual_mod = case as_mod of - Nothing -> this_mod - Just another_name -> another_name - - add_avail :: GlobalNameEnv -> AvailInfo -> RnMG GlobalNameEnv - add_avail env avail = foldlRn add_name env (availNames avail) - - add_name env name = add qual_imp env (Qual qual_mod occ err_hif) `thenRn` \ env1 -> - add unqual_imp env1 (Unqual occ) - where - add False env rdr_name = returnRn env - add True env rdr_name = addOneToGlobalNameEnv env rdr_name (name, name_to_his name) - occ = nameOccName name - - del_avail env avail = foldl delOneFromGlobalNameEnv env rdr_names - where - rdr_names = map (Unqual . nameOccName) (availNames avail) - - add_fixity name_env fix_env (occ_name, fixity) - = add qual $ add unqual $ fix_env - where - qual = Qual qual_mod occ_name err_hif - unqual = Unqual occ_name - - add rdr_name fix_env | maybeToBool (lookupFM name_env rdr_name) - = addOneToFixityEnv fix_env rdr_name fixity - | otherwise - = fix_env - -err_hif = error "qualifyImports: hif" -- Not needed in key to mapping + 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] + + 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)) + where + (main_rdr : sub_rdrs) = tyClDeclNames (unLoc tc_decl) \end{code} -unQualify adds an Unqual binding for every existing Qual binding. - -\begin{code} -unQualify :: FiniteMap RdrName elt -> FiniteMap RdrName elt -unQualify fm = addListToFM fm [(Unqual occ, elt) | (Qual _ occ _, elt) <- fmToList fm] -\end{code} %************************************************************************ %* * -\subsection{Local declarations} +\subsection{Filtering imports} %* * %************************************************************************ +@filterImports@ takes the @ExportEnv@ telling what the imported module makes +available, and filters it through the import spec (if any). \begin{code} -fixityFromFixDecl :: RdrNameFixityDecl -> RnMG (OccName, (Fixity, HowInScope)) +filterImports :: ModIface + -> ImportSpec -- 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) + 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 names + = mkGlobalRdrEnv [ GRE { gre_name = name, gre_prov = Imported [imp_spec] False } + | name <- nameSetToList names ] + +filterImports iface imp_spec Nothing all_names + = returnM (all_names, mkGenericRdrEnv imp_spec all_names) + +filterImports iface imp_spec (Just (want_hiding, import_items)) all_names + = mappM (addLocM get_item) import_items `thenM` \ gres_s -> + let + gres = concat gres_s + specified_names = mkNameSet (map gre_name gres) + in + if not want_hiding then + return (specified_names, mkGlobalRdrEnv gres) + else + let + keep n = not (n `elemNameSet` specified_names) + pruned_avails = filterNameSet keep all_names + in + return (pruned_avails, mkGenericRdrEnv imp_spec pruned_avails) -fixityFromFixDecl (FixityDecl rdr_name fixity loc) - = returnRn (rdrNameOcc rdr_name, (fixity, FromLocalDefn loc)) + where + 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. + + sub_env :: NameEnv [Name] + sub_env = mkSubNameEnv all_names + + bale_out item = addErr (badImportItemErr iface imp_spec item) `thenM_` + returnM [] + + succeed_with :: Bool -> [Name] -> RnM [GlobalRdrElt] + succeed_with all_explicit names + = do { loc <- getSrcSpanM + ; 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) + + 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 + -- both a class and a data constructor. + get_item item@(IEModuleContents _) + = bale_out item + + get_item item@(IEThingAll tc) + = case check_item item of + [] -> 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 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 + [] -> 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} %************************************************************************ %* * -\subsection{Export list processing +\subsection{Export list processing} %* * %************************************************************************ -The @AvailEnv@ type is just used internally in @exportsFromAvail@. -When exporting we need to combine the availabilities for a particular -exported thing, and we also need to check for name clashes -- that -is: two exported things must have different @OccNames@. - -\begin{code} -type AvailEnv = FiniteMap OccName (RdrNameIE, AvailInfo, Int{-no. of clashes-}) - -- The FM maps each OccName to the RdrNameIE that gave rise to it, - -- for error reporting, as well as to its AvailInfo - -emptyAvailEnv = emptyFM - -{- - Add new entry to environment. Checks for name clashes, i.e., - plain duplicates or exported entity pairs that have different OccNames. - (c.f. 5.1.1 of Haskell 1.4 report.) --} -addAvailEnv :: Bool -> RdrNameIE -> AvailEnv -> AvailInfo -> RnM s d AvailEnv -addAvailEnv warn_dups ie env NotAvailable = returnRn env -addAvailEnv warn_dups ie env (AvailTC _ []) = returnRn env -addAvailEnv warn_dups ie env avail - | warn_dups = mapMaybeRn (addErrRn . availClashErr) () conflict `thenRn_` - returnRn (addToFM_C addAvail env key elt) - | otherwise = returnRn (addToFM_C addAvail env key elt) - where - occ_avail = nameOccName (availName avail) - occ_ie = ieOcc ie - key - | not warn_dups || occ_ie == occ_avail = occ_avail - | otherwise = occ_ie - -- export item is a class method, use export occ name instead. - -- (this is only needed to get more precise warnings about - -- duplicates.) - elt = (ie,avail,reports_on) - - reports_on - | maybeToBool dup = 1 - | otherwise = 0 - - conflict = conflictFM bad_avail env key elt - dup - | warn_dups = conflictFM dup_avail env key elt - | otherwise = Nothing - -addListToAvailEnv :: AvailEnv -> RdrNameIE -> [AvailInfo] -> RnM s d AvailEnv -addListToAvailEnv env ie items - = foldlRn (addAvailEnv False{-don't warn about dups-} ie) env items - -bad_avail (ie1,avail1,r1) (ie2,avail2,r2) - = availName avail1 /= availName avail2 -- Same OccName, different Name -dup_avail (ie1,avail1,r1) (ie2,avail2,r2) - = availName avail1 == availName avail2 -- Same OccName & avail. - -addAvail (ie1,a1,r1) (ie2,a2,r2) = (ie1, a1 `plusAvail` a2, r1 + r2) -\end{code} - Processing the export list. -You might think that we should record things that appear in the export list as -``occurrences'' (using addOccurrenceName), but you'd be wrong. We do check (here) -that they are in scope, but there is no need to slurp in their actual declaration -(which is what addOccurrenceName forces). Indeed, doing so would big trouble when -compiling PrelBase, because it re-exports GHC, which includes takeMVar#, whose type -includes ConcBase.StateAndSynchVar#, and so on... +You might think that we should record things that appear in the export +list as ``occurrences'' (using @addOccurrenceName@), but you'd be +wrong. We do check (here) that they are in scope, but there is no +need to slurp in their actual declaration (which is what +@addOccurrenceName@ forces). + +Indeed, doing so would big trouble when compiling @PrelBase@, because +it re-exports @GHC@, which includes @takeMVar#@, whose type includes +@ConcBase.StateAndSynchVar#@, and so on... \begin{code} -exportsFromAvail :: Module - -> Maybe [RdrNameIE] -- Export spec - -> ExportAvails - -> RnEnv - -> RnMG (Name -> ExportFlag, ExportEnv) +type ExportAccum -- The type of the accumulating parameter of + -- the main worker function in exportsFromAvail + = ([Module], -- 'module M's seen so far + ExportOccMap, -- Tracks exported occurrence names + NameSet) -- The accumulated exported stuff +emptyExportAccum = ([], emptyOccEnv, emptyNameSet) + +type ExportOccMap = OccEnv (Name, IE RdrName) + -- Tracks what a particular exported OccName + -- in an export list refers to, and which item + -- it came from. It's illegal to export two distinct things + -- 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 -- Complains if two distinct exports have same OccName -- Warns about identical exports. -- Complains about exports items not in scope -exportsFromAvail this_mod Nothing export_avails rn_env - = exportsFromAvail this_mod (Just [IEModuleContents this_mod]) export_avails rn_env - -exportsFromAvail this_mod (Just export_items) - (mod_avail_env, entity_avail_env) - (RnEnv global_name_env fixity_env) - = checkForModuleExportDups export_items `thenRn` \ export_items' -> - foldlRn exports_from_item emptyAvailEnv export_items' `thenRn` \ export_avail_env -> - let - dup_entries = fmToList (filterFM (\ _ (_,_,clashes) -> clashes > 0) export_avail_env) - in - mapRn (addWarnRn . dupExportWarn) dup_entries `thenRn_` - let - export_avails = map (\ (_,a,_) -> a) (eltsFM export_avail_env) - export_fixities = mk_exported_fixities (availsToNameSet export_avails) - export_fn = mk_export_fn export_avails - in - returnRn (export_fn, ExportEnv export_avails export_fixities) +exportsFromAvail explicit_mod exports + = do { TcGblEnv { tcg_rdr_env = rdr_env, + tcg_imports = imports } <- getGblEnv ; + + -- If the module header is omitted altogether, then behave + -- as if the user had written "module Main(main) where..." + -- EXCEPT in interactive mode, when we behave as if he had + -- written "module Main where ..." + -- Reason: don't want to complain about 'main' not in scope + -- in interactive mode + ghci_mode <- getGhciMode ; + let { real_exports + | explicit_mod = exports + | ghci_mode == Interactive = Nothing + | otherwise = Just [noLoc (IEVar main_RDR_Unqual)] } ; + exports_from_avail real_exports rdr_env imports } + + +exports_from_avail Nothing rdr_env imports + = -- Export all locally-defined things + -- We do this by filtering the global RdrEnv, + -- keeping only things that are locally-defined + return (mkNameSet [ gre_name gre + | gre <- globalRdrEnvElts rdr_env, + isLocalGRE gre ]) + +exports_from_avail (Just items) rdr_env (ImportAvails { imp_env = imp_env }) + = foldlM do_litem emptyExportAccum items `thenM` \ (_, _, exports) -> + returnM exports where - exports_from_item :: AvailEnv -> RdrNameIE -> RnMG AvailEnv - exports_from_item export_avail_env ie@(IEModuleContents mod) - = case lookupFM mod_avail_env mod of - Nothing -> failWithRn export_avail_env (modExportErr mod) - Just avails -> addListToAvailEnv export_avail_env ie avails - - exports_from_item export_avail_env ie - | not (maybeToBool maybe_in_scope) - = failWithRn export_avail_env (unknownNameErr (ieName ie)) - -#ifdef DEBUG - -- I can't see why this should ever happen; if the thing is in scope - -- at all it ought to have some availability - | not (maybeToBool maybe_avail) - = pprTrace "exportsFromAvail: curious Nothing:" (ppr name) - returnRn export_avail_env -#endif - - | not enough_avail - = failWithRn export_avail_env (exportItemErr ie export_avail) - - | otherwise -- Phew! It's OK! - = addAvailEnv opt_WarnDuplicateExports ie export_avail_env export_avail - where - maybe_in_scope = lookupFM global_name_env (ieName ie) - Just (name,_) = maybe_in_scope - maybe_avail = lookupUFM entity_avail_env name - Just avail = maybe_avail - export_avail = filterAvail ie avail - enough_avail = case export_avail of {NotAvailable -> False; other -> True} - - -- We export a fixity iff we export a thing with the same (qualified) RdrName - mk_exported_fixities :: NameSet -> [(OccName, Fixity)] - mk_exported_fixities exports - = fmToList (foldr (perhaps_add_fixity exports) - emptyFM - (fmToList fixity_env)) - - perhaps_add_fixity :: NameSet -> (RdrName, (Fixity, HowInScope)) - -> FiniteMap OccName Fixity - -> FiniteMap OccName Fixity - perhaps_add_fixity exports (rdr_name, (fixity, how_in_scope)) fix_env - = let - do_nothing = fix_env -- The default is to pass on the env unchanged - in - -- Step 1: check whether the rdr_name is in scope; if so find its Name - case lookupFM global_name_env rdr_name of { - Nothing -> do_nothing; - Just (fixity_name,_) -> - - -- Step 2: check whether the fixity thing is exported - if not (fixity_name `elemNameSet` exports) then - do_nothing - else - - -- Step 3: check whether we already have a fixity for the - -- Name's OccName in the fix_env we are building up. This can easily - -- happen. the original fixity_env might contain bindings for - -- M.a and N.a, if a was imported via M and N. - -- If this does happen, we expect the fixity to be the same either way. - let - occ_name = rdrNameOcc rdr_name - in - case lookupFM fix_env occ_name of { - Just fixity1 -> -- Got it already - ASSERT( fixity == fixity1 ) - do_nothing; - Nothing -> - - -- Step 3: add it to the outgoing fix_env - addToFM fix_env occ_name fixity - }} - -{- warn and weed out duplicate module entries from export list. -} -checkForModuleExportDups :: [RdrNameIE] -> RnMG [RdrNameIE] -checkForModuleExportDups ls - | opt_WarnDuplicateExports = check_modules ls - | otherwise = returnRn ls + 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) + | mod `elem` mods -- Duplicate export of M + = do { warn_dup_exports <- doptM Opt_WarnDuplicateExports ; + warnIf warn_dup_exports (dupModuleExport mod) ; + returnM acc } + + | otherwise + = case lookupModuleEnv imp_env mod of + Nothing -> addErr (modExportErr mod) `thenM_` + returnM acc + Just names + -> let + 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 (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 let + new_exports = filterAvail ie name sub_env + in + 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 +-- Checks whether the Name is in scope unqualified, +-- regardless of whether it's ambiguous or not +inScopeUnqual env n = any unQualOK (lookupGRE_Name env n) + +------------------------------- +checkForDodgyExport :: IE RdrName -> [Name] -> RnM () +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 () + +------------------------------- +check_occs :: IE RdrName -> ExportOccMap -> [Name] -> RnM ExportOccMap +check_occs ie occs names + = foldlM check occs names + where + check occs name + = case lookupOccEnv occs name_occ of + Nothing -> returnM (extendOccEnv occs name_occ (name, ie)) + + Just (name', ie') + | name == name' -- Duplicate export + -> do { warn_dup_exports <- doptM Opt_WarnDuplicateExports ; + warnIf warn_dup_exports (dupExportWarn name_occ ie ie') ; + returnM occs } + + | otherwise -- Same occ name but different names: an error + -> do { global_env <- getGlobalRdrEnv ; + addErr (exportClashErr global_env name name' ie ie') ; + returnM occs } + where + name_occ = nameOccName name +\end{code} + +%********************************************************* +%* * + Deprecations +%* * +%********************************************************* + +\begin{code} +reportDeprecations :: TcGblEnv -> RnM () +reportDeprecations tcg_env + = ifOptM Opt_WarnDeprecations $ + do { (eps,hpt) <- getEpsAndHpt + ; mapM_ (check hpt (eps_PIT eps)) all_gres } + where + used_names = findUses (tcg_dus tcg_env) emptyNameSet + all_gres = globalRdrEnvElts (tcg_rdr_env tcg_env) + + 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) $ + addWarn (sep [ptext SLIT("Deprecated use of") <+> + occNameFlavour (nameOccName name) <+> + quotes (ppr name), + (parens imp_msg), + (ppr deprec_txt) ]) + where + name_mod = nameModule name + imp_mod = is_mod 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 + + check hpt pit ok_gre = returnM () -- Local, or not used, or not deprectated + -- The Imported pattern-match: don't deprecate locally defined names + -- For a start, we may be exporting a deprecated thing + -- Also we may use a deprecated thing in the defn of another + -- deprecated things. We may even use a deprecated thing in + -- the defn of a non-deprecated thing, when changing a module's + -- interface + +lookupDeprec :: HomePackageTable -> PackageIfaceTable + -> Name -> Maybe DeprecTxt +lookupDeprec hpt pit n + = case lookupIface hpt pit (nameModule n) of + Just iface -> mi_dep_fn iface n `seqMaybe` -- Bleat if the thing, *or + mi_dep_fn iface (nameParent n) -- its parent*, is deprec'd + Nothing + | isWiredInName n -> Nothing + -- We have not necessarily loaded the .hi file for a + -- wired-in name (yet), although we *could*. + -- And we never deprecate them + + | otherwise -> pprPanic "lookupDeprec" (ppr n) + -- By now all the interfaces should have been loaded + +gre_is_used :: NameSet -> GlobalRdrElt -> Bool +gre_is_used used_names gre = gre_name gre `elemNameSet` used_names +\end{code} + +%********************************************************* +%* * + Unused names +%* * +%********************************************************* + +\begin{code} +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 + ; warnDuplicateImports dup_imps + ; printMinimalImports minimal_imports } + where + used_names, all_used_names :: NameSet + used_names = findUses (tcg_dus gbl_env) emptyNameSet + all_used_names = used_names `unionNameSets` + mkNameSet (mapCatMaybes nameParent_maybe (nameSetToList used_names)) + -- A use of C implies a use of T, + -- if C was brought into scope by T(..) or T(C) + + -- Collect the defined names from the in-scope environment + defined_names :: [GlobalRdrElt] + defined_names = globalRdrEnvElts (tcg_rdr_env gbl_env) + + -- Note that defined_and_used, defined_but_not_used + -- are both [GRE]; that's why we need defined_and_used + -- rather than just all_used_names + defined_and_used, defined_but_not_used :: [GlobalRdrElt] + (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 + -- The latter have an Internal Name, so we can filter them out easily + unused_locals :: [GlobalRdrElt] + unused_locals = filter is_unused_local defined_but_not_used + is_unused_local :: GlobalRdrElt -> Bool + is_unused_local gre = isLocalGRE gre && isExternalName (gre_name gre) + + 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) + -- Don't complain about unused imports if we've already said the + -- entire import is unused + unused_imp other = False + + -- 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 = 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 + -- even if we import nothing explicitly. + -- It's not necessarily redundant to import such modules. Consider + -- module This + -- import M () + -- + -- The import M() is not *necessarily* redundant, even if + -- we suck in no instance decls from M (e.g. it contains + -- no instance decls, or This contains no code). It may be + -- that we import M solely to ensure that M's orphan instance + -- decls (or those in its imports) are visible to people who + -- import This. Sigh. + -- There's really no good way to detect this, so the error message + -- in RnEnv.warnUnusedModules is weakened instead + + -- 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)) + (unitAvailEnv (mk_avail n (nameParent_maybe n))) + 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] + | otherwise = Avail n + + add_inst_mod (mod,_,_) acc + | mod `elemFM` acc = acc -- We import something already + | otherwise = addToFM acc mod emptyAvailEnv + where + -- Add an empty collection of imports for a module + -- from which we have sucked only instance decls + + imports = tcg_imports gbl_env + + direct_import_mods :: [(Module, Maybe Bool, SrcSpan)] + -- See the type of the imp_mods for this triple + direct_import_mods = moduleEnvElts (imp_mods imports) + + -- unused_imp_mods are the directly-imported modules + -- 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, + imp /= Just False] + -- The Just False part is not to complain about + -- import M (), which is an idiom for importing + -- instance declarations + + module_unused :: Module -> Bool + module_unused mod = any (((==) mod) . fst) unused_imp_mods + +--------------------- +warnDuplicateImports :: [GlobalRdrElt] -> RnM () +warnDuplicateImports gres + = ifOptM Opt_WarnUnusedImports (mapM_ warn gres) where - -- NOTE: reorders the export list by moving all module-contents - -- exports to the end (removing duplicates in the process.) - check_modules ls = - (case dups of - [] -> returnRn () - ls -> mapRn (\ ds@(IEModuleContents x:_) -> - addWarnRn (dupModuleExport x (length ds))) ls `thenRn_` - returnRn ()) `thenRn_` - returnRn (ls_no_modules ++ no_module_dups) - where - (ls_no_modules,modules) = foldr split_mods ([],[]) ls - - split_mods i@(IEModuleContents _) (no_ms,ms) = (no_ms,i:ms) - split_mods i (no_ms,ms) = (i:no_ms,ms) - - (no_module_dups, dups) = removeDups cmp_mods modules - - cmp_mods (IEModuleContents m1) (IEModuleContents m2) = m1 `compare` m2 - -mk_export_fn :: [AvailInfo] -> (Name -> ExportFlag) -mk_export_fn avails - = \name -> if name `elemNameSet` exported_names - then Exported - else NotExported + 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))) + + +-- ToDo: deal with original imports with 'qualified' and 'as M' clauses +printMinimalImports :: FiniteMap Module AvailEnv -- Minimal imports + -> RnM () +printMinimalImports imps + = ifOptM Opt_D_dump_minimal_imports $ do { + + mod_ies <- mappM to_ies (fmToList imps) ; + this_mod <- getModule ; + rdr_env <- getGlobalRdrEnv ; + ioToTcRn (do { h <- openFile (mkFilename this_mod) WriteMode ; + printForUser h (unQualInScope rdr_env) + (vcat (map ppr_mod_ie mod_ies)) }) + } where - exported_names :: NameSet - exported_names = availsToNameSet avails + mkFilename this_mod = moduleUserString this_mod ++ ".imports" + ppr_mod_ie (mod_name, ies) + | mod_name == pRELUDE + = empty + | null ies -- Nothing except instances comes from here + = ptext SLIT("import") <+> ppr mod_name <> ptext SLIT("() -- Instances only") + | otherwise + = ptext SLIT("import") <+> ppr mod_name <> + parens (fsep (punctuate comma (map ppr ies))) + + to_ies (mod, avail_env) = mappM to_ie (availEnvElts avail_env) `thenM` \ ies -> + returnM (mod, ies) + + to_ie :: AvailInfo -> RnM (IE Name) + -- The main trick here is that if we're importing all the constructors + -- we want to say "T(..)", but if we're importing only a subset we want + -- to say "T(A,B,C)". So we have to find out what the module exports. + to_ie (Avail n) = returnM (IEVar n) + to_ie (AvailTC n [m]) = ASSERT( n==m ) + returnM (IEThingAbs n) + to_ie (AvailTC n ns) + = loadSrcInterface doc n_mod False `thenM` \ iface -> + case [xs | (m,as) <- mi_exports iface, + m == n_mod, + AvailTC x xs <- as, + x == nameOccName n] of + [xs] | all_used xs -> returnM (IEThingAll n) + | otherwise -> returnM (IEThingWith n (filter (/= n) ns)) + other -> pprTrace "to_ie" (ppr n <+> ppr n_mod <+> ppr other) $ + returnM (IEVar n) + where + all_used avail_occs = all (`elem` map nameOccName ns) avail_occs + doc = text "Compute minimal imports from" <+> ppr n + n_mod = nameModule n \end{code} + %************************************************************************ %* * \subsection{Errors} @@ -628,38 +969,65 @@ mk_export_fn avails %************************************************************************ \begin{code} -badImportItemErr mod ie - = sep [ptext SLIT("Module"), quotes (pprModule mod), +badImportItemErr iface imp_spec ie + = sep [ptext SLIT("Module"), quotes (ppr (is_mod imp_spec)), source_import, ptext SLIT("does not export"), quotes (ppr ie)] + where + source_import | mi_boot iface = ptext SLIT("(hi-boot interface)") + | otherwise = empty -dodgyImportWarn mod (IEThingAll tc) - = sep [ptext SLIT("Module") <+> quotes (pprModule mod) <+> ptext SLIT("exports") <+> quotes (ppr tc), - ptext SLIT("with no constructors/class operations;"), - ptext SLIT("yet it is imported with a (..)")] +dodgyImportWarn item = dodgyMsg (ptext SLIT("import")) item +dodgyExportWarn item = dodgyMsg (ptext SLIT("export")) item +dodgyMsg kind tc + = sep [ ptext SLIT("The") <+> kind <+> ptext SLIT("item") <+> quotes (ppr (IEThingAll tc)), + ptext SLIT("suggests that") <+> quotes (ppr tc) <+> ptext SLIT("has constructor or class methods"), + ptext SLIT("but it has none; it is a type synonym or abstract type or class") ] + modExportErr mod - = hsep [ ptext SLIT("Unknown module in export list: module"), quotes (pprModule mod)] - -exportItemErr export_item NotAvailable - = sep [ ptext SLIT("Export item not in scope:"), quotes (ppr export_item)] + = hsep [ ptext SLIT("Unknown module in export list: module"), quotes (ppr mod)] -exportItemErr export_item avail - = hang (ptext SLIT("Export item not fully in scope:")) - 4 (vcat [hsep [ptext SLIT("Wanted: "), ppr export_item], - hsep [ptext SLIT("Available:"), ppr (ieOcc export_item), pprAvail avail]]) +exportItemErr export_item + = sep [ ptext SLIT("The export item") <+> quotes (ppr export_item), + ptext SLIT("attempts to export constructors or class methods that are not visible here") ] -availClashErr (occ_name, ((ie1,avail1,_), (ie2,avail2,_))) - = hsep [ptext SLIT("The export items"), quotes (ppr ie1), ptext SLIT("and"), quotes (ppr ie2), - ptext SLIT("create conflicting exports for"), quotes (ppr occ_name)] +exportClashErr global_env name1 name2 ie1 ie2 + = vcat [ ptext SLIT("Conflicting exports for") <+> quotes (ppr occ) <> colon + , ppr_export ie1 name1 + , ppr_export ie2 name2 ] + where + occ = nameOccName name1 + ppr_export ie name = nest 2 (quotes (ppr ie) <+> ptext SLIT("exports") <+> + quotes (ppr name) <+> pprNameProvenance (get_gre name)) + + -- get_gre finds a GRE for the Name, so that we can show its provenance + get_gre name + = case lookupGRE_Name global_env name of + (gre:_) -> gre + [] -> pprPanic "exportClashErr" (ppr name) + +addDupDeclErr :: [Name] -> TcRn () +addDupDeclErr names + = addErrAt big_loc $ + vcat [ptext SLIT("Multiple declarations of") <+> quotes (ppr name1), + ptext SLIT("Declared at:") <+> vcat (map ppr sorted_locs)] + where + locs = map nameSrcLoc names + big_loc = foldr1 combineSrcSpans (map srcLocSpan locs) + name1 = head names + sorted_locs = sortLe (<=) (sortLe (<=) locs) -dupExportWarn (occ_name, (_,_,times)) +dupExportWarn occ_name ie1 ie2 = hsep [quotes (ppr occ_name), - ptext SLIT("mentioned"), speakNTimes (times+1), - ptext SLIT("in export list")] + ptext SLIT("is exported by"), quotes (ppr ie1), + ptext SLIT("and"), quotes (ppr ie2)] -dupModuleExport mod times - = hsep [ptext SLIT("Module"), quotes (pprModule mod), - ptext SLIT("mentioned"), speakNTimes times, +dupModuleExport mod + = hsep [ptext SLIT("Duplicate"), + quotes (ptext SLIT("Module") <+> ppr mod), ptext SLIT("in export list")] -\end{code} +moduleDeprec mod txt + = sep [ ptext SLIT("Module") <+> quotes (ppr mod) <+> ptext SLIT("is deprecated:"), + nest 4 (ppr txt) ] +\end{code}