X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Fcompiler%2Frename%2FRnNames.lhs;h=2eb5a8de42de0c3f26ed1f548363c92af78274cf;hb=d191be5da8d2934a5c50bdbc605784d6a9043b6f;hp=d4d6befada4916c15abccfb8a245a9a54ec8f57e;hpb=5c750a880cdd8ae0e626fe5ff3f1cafd1324d48c;p=ghc-hetmet.git diff --git a/ghc/compiler/rename/RnNames.lhs b/ghc/compiler/rename/RnNames.lhs index d4d6bef..656d131 100644 --- a/ghc/compiler/rename/RnNames.lhs +++ b/ghc/compiler/rename/RnNames.lhs @@ -1,557 +1,974 @@ % -% (c) The GRASP/AQUA Project, Glasgow University, 1992-1996 +% (c) The GRASP/AQUA Project, Glasgow University, 1992-1998 % \section[RnNames]{Extracting imported and top-level names in scope} \begin{code} -#include "HsVersions.h" - module RnNames ( - getGlobalNames + rnImports, importsFromLocalDecls, exportsFromAvail, + reportUnusedNames, reportDeprecations, + mkModDeps, exportsToAvails ) where -IMP_Ubiq() +#include "HsVersions.h" -import CmdLineOpts ( opt_SourceUnchanged, opt_NoImplicitPrelude, - opt_WarnDuplicateExports +import CmdLineOpts ( DynFlag(..) ) +import HsSyn ( IE(..), ieName, ImportDecl(..), LImportDecl, + ForeignDecl(..), HsGroup(..), + collectGroupBinders, tyClDeclNames ) -import HsSyn ( HsModule(..), HsDecl(..), FixityDecl(..), Fixity, Fake, InPat, IE(..), HsTyVar, - TyDecl, ClassDecl, InstDecl, DefaultDecl, ImportDecl(..), HsBinds, IfaceSig, - collectTopBinders - ) -import HsImpExp ( ieName ) -import RdrHsSyn ( RdrNameHsDecl(..), RdrName(..), RdrNameIE(..), SYN_IE(RdrNameImportDecl), - SYN_IE(RdrNameHsModule), SYN_IE(RdrNameFixityDecl), - rdrNameOcc, ieOcc - ) -import RnHsSyn ( RenamedHsModule(..), RenamedFixityDecl(..) ) -import RnIfaces ( getInterfaceExports, getDeclBinders, checkUpToDate, recordSlurp ) -import BasicTypes ( IfaceFlavour(..) ) import RnEnv -import RnMonad +import IfaceEnv ( lookupOrig, newGlobalBinder ) +import LoadIface ( loadSrcInterface ) +import TcRnMonad import FiniteMap -import PrelMods -import UniqFM ( UniqFM, emptyUFM, addListToUFM_C, lookupUFM ) -import Bag ( Bag, bagToList ) -import Maybes ( maybeToBool, expectJust ) -import Name -import Pretty -import Outputable ( Outputable(..), PprStyle(..) ) -import Util ( panic, pprTrace, assertPanic, removeDups, cmpPString ) +import PrelNames ( pRELUDE_Name, isBuiltInSyntaxName, isUnboundName, + main_RDR_Unqual ) +import Module ( Module, ModuleName, moduleName, mkPackageModule, + moduleNameUserString, isHomeModule, + unitModuleEnvByName, unitModuleEnv, + lookupModuleEnvByName, moduleEnvElts ) +import Name ( Name, nameSrcLoc, nameOccName, nameModuleName, + nameParent, nameParent_maybe, isExternalName, nameModule ) +import NameSet +import NameEnv +import OccName ( srcDataName, isTcOcc, occNameFlavour, OccEnv, + mkOccEnv, lookupOccEnv, emptyOccEnv, extendOccEnv ) +import HscTypes ( GenAvailInfo(..), AvailInfo, Avails, GhciMode(..), + IfaceExport, HomePackageTable, PackageIfaceTable, + availName, availNames, availsToNameSet, unQualInScope, + Deprecs(..), ModIface(..), Dependencies(..), lookupIface, + ExternalPackageState(..) + ) +import RdrName ( RdrName, rdrNameOcc, setRdrNameSpace, + GlobalRdrEnv, mkGlobalRdrEnv, GlobalRdrElt(..), + emptyGlobalRdrEnv, plusGlobalRdrEnv, globalRdrEnvElts, + unQualOK, lookupGRE_Name, + Provenance(..), ImportSpec(..), + isLocalGRE, pprNameProvenance ) +import Outputable +import Maybes ( isJust, isNothing, catMaybes, mapCatMaybes, seqMaybe ) +import SrcLoc ( noSrcLoc, Located(..), mkGeneralSrcSpan, + unLoc, noLoc ) +import BasicTypes ( DeprecTxt ) +import ListSetOps ( removeDups ) +import Util ( sortLt, notNull, isSingleton ) +import List ( partition, insert ) +import IO ( openFile, IOMode(..) ) \end{code} %************************************************************************ %* * -\subsection{Get global names} + rnImports %* * %************************************************************************ \begin{code} -getGlobalNames :: RdrNameHsModule - -> RnMG (Maybe (ExportEnv, RnEnv, NameSet)) - -- Nothing <=> no need to recompile - -- The NameSet is the set of names that are - -- either locally defined, - -- or explicitly imported - -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_avails) -> - - -- PROCESS IMPORT DECLS - mapAndUnzip3Rn importsFromImportDecl all_imports - `thenRn` \ (imp_rn_envs, imp_avails_s, explicit_imports_s) -> - - -- CHECK FOR EARLY EXIT - checkEarlyExit this_mod `thenRn` \ early_exit -> - if early_exit then - returnRn (junk_exp_fn, Nothing) - else - - -- 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 -> - let - export_avails :: ExportAvails - export_avails = foldr plusExportAvails local_mod_avails imp_avails_s - - explicit_names :: NameSet -- locally defined or explicitly imported - explicit_names = foldr add_on emptyNameSet (local_avails : explicit_imports_s) - add_on avails names = foldr (unionNameSets . mkNameSet . availNames) names avails - in - - -- PROCESS EXPORT LISTS - exportsFromAvail this_mod exports export_avails rn_env - `thenRn` \ (export_fn, export_env) -> - - -- RECORD THAT LOCALLY DEFINED THINGS ARE AVAILABLE - mapRn (recordSlurp Nothing Compulsory) local_avails `thenRn_` - - returnRn (export_fn, Just (export_env, rn_env, explicit_names)) - ) `thenRn` \ (_, result) -> - returnRn result - where - junk_exp_fn = error "RnNames:export_fn" +rnImports :: [LImportDecl RdrName] + -> RnM (GlobalRdrEnv, ImportAvails) + +rnImports imports + = -- PROCESS IMPORT DECLS + -- Do the non {- SOURCE -} ones first, so that we get a helpful + -- warning for {- SOURCE -} ones that are unnecessary + getModule `thenM` \ this_mod -> + doptM Opt_NoImplicitPrelude `thenM` \ opt_no_prelude -> + let + all_imports = mk_prel_imports this_mod opt_no_prelude ++ imports + (source, ordinary) = partition is_source_import all_imports + is_source_import (L _ (ImportDecl _ is_boot _ _ _)) = is_boot + + get_imports = importsFromImportDecl this_mod + in + mappM get_imports ordinary `thenM` \ stuff1 -> + mappM get_imports source `thenM` \ stuff2 -> - all_imports = prel_imports ++ imports + -- 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 + in + -- ALL DONE + returnM (gbl_env, all_avails) + where -- 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] - + -- because the former doesn't even look at Prelude.hi for instance + -- declarations, whereas the latter does. + mk_prel_imports this_mod no_prelude + | moduleName this_mod == pRELUDE_Name + || explicit_prelude_import + || no_prelude + = [] + + | otherwise = [preludeImportDecl] + explicit_prelude_import - = not (null [ () | (ImportDecl mod qual _ _ _ _) <- imports, mod == pRELUDE ]) + = notNull [ () | L _ (ImportDecl mod _ _ _ _) <- imports, + unLoc mod == pRELUDE_Name ] + +preludeImportDecl + = L loc $ + ImportDecl (L loc pRELUDE_Name) + 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 - 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 - -- 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} - +importsFromImportDecl :: Module + -> LImportDecl RdrName + -> RnM (GlobalRdrEnv, ImportAvails) -\begin{code} -importsFromImportDecl :: RdrNameImportDecl - -> RnMG (RnEnv, ExportAvails, [AvailInfo]) +importsFromImportDecl this_mod + (L loc (ImportDecl loc_imp_mod_name want_boot qual_only as_mod imp_details)) + = + addSrcSpan loc $ -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 - filtered_avails' = map set_avail_prov filtered_avails - fixities' = [ (occ,(fixity,provenance)) | (occ,fixity) <- fixities ] + imp_mod_name = unLoc loc_imp_mod_name + this_mod_name = moduleName this_mod + 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 - (ExportEnv filtered_avails' fixities') - hides - `thenRn` \ (rn_env, mod_avails) -> - returnRn (rn_env, mod_avails, explicits) - where - set_avail_prov NotAvailable = NotAvailable - set_avail_prov (Avail n) = Avail (set_name_prov n) - set_avail_prov (AvailTC n ns) = AvailTC (set_name_prov n) (map set_name_prov ns) - set_name_prov name | isWiredInName name = name - | otherwise = setNameProvenance name provenance - provenance = Imported mod loc as_source -\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 -> - mapRn fixityFromFixDecl fix_decls `thenRn` \ fixities -> - qualifyImports mod - False -- Don't want qualified names - True -- Want unqualified names - Nothing -- No "as M" part - (ExportEnv avails fixities) - [] -- Hide nothing - `thenRn` \ (rn_env, mod_avails) -> - returnRn (rn_env, mod_avails, 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_` + + 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_name + -- 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) -> + + let + -- Compute new transitive dependencies + orphans | is_orph = insert imp_mod_name (dep_orphs deps) + | otherwise = dep_orphs deps + + (dependent_mods, dependent_pkgs) + | isHomeModule imp_mod + = -- Imported module is from the home package + -- Take its dependent modules and + -- (a) remove this_mod (might be there as a hi-boot) + -- (b) add imp_mod itself + -- Take its dependent packages unchanged + ((imp_mod_name, want_boot) : filter not_self (dep_mods deps), dep_pkgs deps) + + | otherwise + = -- Imported module is from another package + -- Dump the dependent modules + -- Add the package imp_mod comes from to the dependent packages + -- from imp_mod + ([], insert (mi_package iface) (dep_pkgs deps)) + + not_self (m, _) = m /= this_mod_name + + 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_qual = unitModuleEnvByName qual_mod_name avail_env, + imp_env = avail_env, + imp_mods = unitModuleEnv imp_mod (imp_mod, import_all), + imp_orphs = orphans, + imp_dep_mods = mkModDeps dependent_mods, + imp_dep_pkgs = dependent_pkgs } + + in + -- 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 Avails +exportsToAvails exports + = do { avails_by_module <- mappM do_one exports + ; return (concat avails_by_module) } 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) - - 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 (mod_name, exports) = mapM (do_avail mod_name) exports + do_avail mod_nm (Avail n) = do { n' <- lookupOrig mod_nm n; + ; return (Avail n') } + do_avail mod_nm (AvailTC n ns) = do { n' <- lookupOrig mod_nm n + ; ns' <- mappM (lookup_sub n') ns + ; return (AvailTC n' ns') } + where + mod = mkPackageModule mod_nm -- Not necessarily right yet + 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. + -- 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_ (addErr . dupDeclErr) dups `thenM_` - where - import_fm :: FiniteMap OccName AvailInfo - import_fm = listToFM [ (nameOccName name, avail) - | avail <- avails, - name <- availEntityNames avail] + doptM Opt_NoImplicitPrelude `thenM` \ implicit_prelude -> + let + mod_name = moduleName this_mod + prov = LocalDef mod_name + 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 avails, not avails' in + -- defn of gbl_env 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. + + avails' | implicit_prelude = filter not_built_in_syntax avails + | otherwise = avails + not_built_in_syntax a = not (all isBuiltInSyntaxName (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 isBuiltInSyntaxName] + + avail_env = mkAvailEnv avails' + imports = emptyImportAvails { + imp_qual = unitModuleEnv this_mod avail_env, + imp_env = avail_env + } + in + returnM (gbl_env, imports) +\end{code} - 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 +%********************************************************* +%* * +\subsection{Getting binders out of a declaration} +%* * +%********************************************************* - | 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 -\end{code} +@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 -> + mappM new_simple (for_hs_bndrs ++ val_hs_bndrs) `thenM` \ simple_avails -> + returnM (tc_avails ++ simple_avails) + where + new_simple rdr_name = newTopSrcBinder mod Nothing rdr_name `thenM` \ name -> + returnM (Avail name) + + 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} %************************************************************************ %* * -\subsection{Qualifiying imports} +\subsection{Filtering imports} %* * %************************************************************************ -@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@. +@filterImports@ takes the @ExportEnv@ telling what the imported module makes +available, and filters it through the import spec (if any). \begin{code} -qualifyImports :: Module -- Imported module - -> Bool -- True <=> want qualified import - -> Bool -- True <=> want unqualified import - -> Maybe Module -- Optional "as M" part - -> ExportEnv -- What's imported - -> [AvailInfo] -- What's to be hidden - -> RnMG (RnEnv, ExportAvails) - -qualifyImports this_mod qual_imp unqual_imp as_mod (ExportEnv avails fixities) hides - = - -- 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 emptyNameEnv avails `thenRn` \ name_env1 -> - let - -- Delete things that are hidden - name_env2 = foldl del_avail name_env1 hides +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 + GlobalRdrEnv) -- ...in two forms - -- Create the fixity env - fixity_env = foldl (add_fixity name_env2) emptyFixityEnv fixities + -- Complains if import spec mentions things that the module doesn't export + -- Warns/informs if import spec contains duplicates. +mkGenericRdrEnv imp_spec avails + = mkGlobalRdrEnv [ GRE { gre_name = name, gre_prov = Imported [imp_spec] False } + | avail <- avails, name <- availNames avail ] + +filterImports iface imp_spec Nothing total_avails + = returnM (mkAvailEnv total_avails, mkGenericRdrEnv imp_spec total_avails) - -- Create the export-availability info - export_avails = mkExportAvails unqual_imp qual_mod avails +filterImports iface imp_spec (Just (want_hiding, import_items)) total_avails + = mapAndUnzipM (addLocM get_item) import_items `thenM` \ (avails, gres) -> + let + all_avails = foldr plusAvailEnv emptyAvailEnv avails + rdr_env = foldr plusGlobalRdrEnv emptyGlobalRdrEnv gres in - returnRn (RnEnv name_env2 fixity_env, export_avails) + if not want_hiding then + returnM (all_avails, rdr_env) + else + let -- Hide stuff in all_avails + hidden = availsToNameSet (availEnvElts all_avails) + keep n = not (n `elemNameSet` hidden) + pruned_avails = pruneAvails keep total_avails + in + returnM (mkAvailEnv pruned_avails, mkGenericRdrEnv imp_spec pruned_avails) where - qual_mod = case as_mod of - Nothing -> this_mod - Just another_name -> another_name - - 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 = addOneToNameEnv env rdr_name name - occ = nameOccName name - - del_avail env avail = foldl delOneFromNameEnv env rdr_names - where - rdr_names = map (Unqual . nameOccName) (availNames avail) - - add_fixity name_env fix_env (occ_name, (fixity, provenance)) - = 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,provenance) - | otherwise - = fix_env - -err_hif = error "qualifyImports: hif" -- Not needed in key to mapping -\end{code} + import_fm :: OccEnv AvailInfo + import_fm = mkOccEnv [ (nameOccName name, avail) + | avail <- total_avails, + name <- availNames avail] + -- Even though availNames returns 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 (emptyAvailEnv, emptyGlobalRdrEnv) + + succeed_with :: Bool -> AvailInfo -> RnM (AvailEnv, GlobalRdrEnv) + succeed_with all_explicit avail + = do { loc <- getSrcSpanM + ; returnM (unitAvailEnv avail, + mkGlobalRdrEnv (map (mk_gre loc) (availNames avail))) } + 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 + + get_item :: IE RdrName -> RnM (AvailEnv, GlobalRdrEnv) + -- 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 + 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_WarnMisc (addWarn (dodgyImportWarn tc)) `thenM_` + succeed_with False avail + Just avail -> succeed_with False avail + + get_item item@(IEThingAbs n) + | want_hiding -- hiding( C ) + -- Here the 'C' can be a data constructor *or* a type/class + = case catMaybes [check_item item, check_item (IEVar data_n)] of + [] -> bale_out item + avails -> returnM (mkAvailEnv avails, emptyGlobalRdrEnv) + -- The GlobalRdrEnv result is irrelevant when hiding + where + data_n = setRdrNameSpace n srcDataName -unQualify adds an Unqual binding for every existing Qual binding. + get_item item + = case check_item item of + Nothing -> bale_out item + Just avail -> succeed_with True avail -\begin{code} -unQualify :: FiniteMap RdrName elt -> FiniteMap RdrName elt -unQualify fm = addListToFM fm [(Unqual occ, elt) | (Qual _ occ _, elt) <- fmToList fm] -\end{code} + check_item item + | isNothing maybe_in_import_avails || + isNothing maybe_filtered_avail + = Nothing -%************************************************************************ -%* * -\subsection{Local declarations} -%* * -%************************************************************************ + | 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} -fixityFromFixDecl :: RdrNameFixityDecl -> RnMG (OccName, (Fixity, Provenance)) - -fixityFromFixDecl (FixityDecl rdr_name fixity loc) - = returnRn (rdrNameOcc rdr_name, (fixity, LocalDef (panic "export-flag") loc)) +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 \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@. +Processing the export list. -\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 ie env NotAvailable = returnRn env -addAvailEnv ie env (AvailTC _ []) = returnRn env -addAvailEnv ie env avail - = mapMaybeRn (addErrRn . availClashErr) () conflict `thenRn_` - returnRn (addToFM_C add_avail env key elt) - where - key = nameOccName (availName avail) - elt = (ie,avail,reports_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). - reports_on - | maybeToBool dup = 1 - | otherwise = 0 +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... - conflict = conflictFM bad_avail env key elt - dup - | opt_WarnDuplicateExports = conflictFM dup_avail env key elt - | otherwise = Nothing +\begin{code} +type ExportAccum -- The type of the accumulating parameter of + -- the main worker function in exportsFromAvail + = ([ModuleName], -- 'module M's seen so far + ExportOccMap, -- Tracks exported occurrence names + AvailEnv) -- The accumulated exported stuff, kept in an env + -- so we can common-up related AvailInfos +emptyExportAccum = ([], emptyOccEnv, emptyAvailEnv) + +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 Avails + -- Complains if two distinct exports have same OccName + -- Warns about identical exports. + -- Complains about exports items not in scope -addListToAvailEnv :: AvailEnv -> RdrNameIE -> [AvailInfo] -> RnM s d AvailEnv -addListToAvailEnv env ie items = foldlRn (addAvailEnv ie) env items +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@(ImportAvails { imp_env = entity_avail_env }) + = -- Export all locally-defined things + -- We do this by filtering the global RdrEnv, + -- keeping only things that are (a) qualified, + -- (b) locally defined, (c) a 'main' name + -- Then we look up in the entity-avail-env + return [ lookupAvailEnv entity_avail_env name + | gre <- globalRdrEnvElts rdr_env, + isLocalGRE gre, + let name = gre_name gre, + isNothing (nameParent_maybe name) -- Main things only + ] + +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` \ (_, _, export_avail_map) -> + returnM (nameEnvElts export_avail_map) -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. + where + exports_from_litem :: ExportAccum -> Located (IE RdrName) -> RnM ExportAccum + exports_from_litem acc = addLocM (exports_from_item acc) + + exports_from_item :: ExportAccum -> IE RdrName -> RnM ExportAccum + exports_from_item acc@(mods, occs, avails) 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 lookupModuleEnvByName mod_avail_env mod of + Nothing -> addErr (modExportErr mod) `thenM_` + returnM acc + + Just avail_env + -> let + mod_avails = [ filtered_avail + | avail <- availEnvElts avail_env, + let mb_avail = filter_unqual rdr_env avail, + isJust mb_avail, + let Just filtered_avail = mb_avail] + + avails' = foldl addAvail avails mod_avails + 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. + + foldlM (check_occs ie) occs mod_avails `thenM` \ occs' -> + returnM (mod:mods, occs', avails') + + exports_from_item acc@(mods, occs, avails) 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 + 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! + checkForDodgyExport ie avail `thenM_` + check_occs ie occs export_avail `thenM` \ occs' -> + returnM (mods, occs', addAvail avails export_avail) + } + + +------------------------------- +filter_unqual :: GlobalRdrEnv -> AvailInfo -> Maybe AvailInfo +-- Filter the Avail by what's in scope unqualified +filter_unqual env (Avail n) + | in_scope env n = Just (Avail n) + | otherwise = Nothing +filter_unqual env (AvailTC n ns) + | not (null ns') = Just (AvailTC n ns') + | otherwise = Nothing + where + ns' = filter (in_scope env) ns + +in_scope :: GlobalRdrEnv -> Name -> Bool +-- Checks whether the Name is in scope unqualified, +-- regardless of whether it's ambiguous or not +in_scope env n = any unQualOK (lookupGRE_Name env n) + +------------------------------- +checkForDodgyExport :: IE RdrName -> AvailInfo -> RnM () +checkForDodgyExport (IEThingAll tc) (AvailTC _ [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 _ _ = return () + +------------------------------- +check_occs :: IE RdrName -> ExportOccMap -> AvailInfo -> RnM ExportOccMap +check_occs ie occs avail + = foldlM check occs (availNames avail) + 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} -add_avail (ie1,a1,r1) (ie2,a2,r2) = (ie1, a1 `plusAvail` a2, r1 + r2) +%********************************************************* +%* * + Deprecations +%* * +%********************************************************* +\begin{code} +reportDeprecations :: TcGblEnv -> RnM () +reportDeprecations tcg_env + = ifOptM Opt_WarnDeprecations $ + do { hpt <- getHpt + ; eps <- getEps + ; 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 + = addSrcSpan (is_loc imp_spec) $ + addWarn (sep [ptext SLIT("Deprecated use of") <+> + text (occNameFlavour (nameOccName name)) <+> + quotes (ppr name), + (parens imp_msg), + (ppr deprec_txt) ]) + where + name_mod = nameModuleName 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 -> 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} -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... +%********************************************************* +%* * + Unused names +%* * +%********************************************************* \begin{code} -exportsFromAvail :: Module - -> Maybe [RdrNameIE] -- Export spec - -> ExportAvails - -> RnEnv - -> RnMG (Name -> ExportFlag, ExportEnv) - -- 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 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) - +reportUnusedNames :: TcGblEnv -> RnM () +reportUnusedNames gbl_env + = do { warnUnusedTopBinds unused_locals + ; warnUnusedModules unused_imp_mods + ; warnUnusedImports unused_imports + ; warnDuplicateImports dup_imps + ; printMinimalImports minimal_imports } 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 PprDebug name) - returnRn export_avail_env -#endif - - | not enough_avail - = failWithRn export_avail_env (exportItemErr ie export_avail) - - | otherwise -- Phew! It's OK! - = addAvailEnv ie export_avail_env export_avail - where - maybe_in_scope = lookupNameEnv 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, Provenance))] - mk_exported_fixities exports - = fmToList (foldr (perhaps_add_fixity exports) - emptyFM - (fmToList fixity_env)) - - perhaps_add_fixity :: NameSet -> (RdrName, (Fixity, Provenance)) - -> FiniteMap OccName (Fixity,Provenance) - -> FiniteMap OccName (Fixity,Provenance) - perhaps_add_fixity exports (rdr_name, (fixity, prov)) 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 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, prov1) -> -- Got it already - ASSERT( fixity == fixity1 ) - do_nothing; - Nothing -> - - -- Step 3: add it to the outgoing fix_env - addToFM fix_env occ_name (fixity,prov) - }} - -{- warn and weed out duplicate module entries from export list. -} -checkForModuleExportDups :: [RdrNameIE] -> RnMG [RdrNameIE] -checkForModuleExportDups ls - | opt_WarnDuplicateExports = check_modules ls - | otherwise = returnRn ls + 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 + minimal_imports :: FiniteMap ModuleName AvailEnv + minimal_imports0 = emptyFM + 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 + + -- 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 m acc + | m `elemFM` acc = acc -- We import something already + | otherwise = addToFM acc m emptyAvailEnv + -- 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 :: [ModuleName] + direct_import_mods = map (moduleName . fst) + (moduleEnvElts (imp_mods imports)) + + hasEmptyImpList :: ModuleName -> Bool + hasEmptyImpList m = + case lookupModuleEnvByName (imp_mods imports) m of + Just (_,Just x) -> not x + _ -> False + + -- 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] + unused_imp_mods = [m | m <- direct_import_mods, + isNothing (lookupFM minimal_imports1 m), + m /= pRELUDE_Name, + not (hasEmptyImpList m)] + -- hasEmptyImpList arranges not to complain about + -- import M (), which is an idiom for importing + -- instance declarations + + module_unused :: ModuleName -> Bool + module_unused mod = mod `elem` 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 `cmpPString` 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 ModuleName 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 = moduleNameUserString (moduleName this_mod) ++ ".imports" + ppr_mod_ie (mod_name, ies) + | mod_name == pRELUDE_Name + = 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 = nameModuleName n \end{code} + %************************************************************************ %* * \subsection{Errors} @@ -559,39 +976,61 @@ mk_export_fn avails %************************************************************************ \begin{code} -badImportItemErr mod ie sty - = sep [ptext SLIT("Module"), pprModule sty mod, ptext SLIT("does not export"), ppr sty ie] - -modExportErr mod sty - = hsep [ ptext SLIT("Unknown module in export list: module"), ptext mod] - -exportItemErr export_item NotAvailable sty - = sep [ ptext SLIT("Export item not in scope:"), ppr sty export_item ] - -exportItemErr export_item avail sty - = hang (ptext SLIT("Export item not fully in scope:")) - 4 (vcat [hsep [ptext SLIT("Wanted: "), ppr sty export_item], - hsep [ptext SLIT("Available:"), ppr sty (ieOcc export_item), pprAvail sty avail]]) - -availClashErr (occ_name, ((ie1,avail1,_), (ie2,avail2,_))) sty - = hsep [ptext SLIT("The export items"), ppr sty ie1, ptext SLIT("and"), ppr sty ie2, - ptext SLIT("create conflicting exports for"), ppr sty occ_name] +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 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 (ppr mod)] + +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") ] + +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) + +dupDeclErr (n:ns) + = vcat [ptext SLIT("Multiple declarations of") <+> quotes (ppr n), + nest 4 (vcat (map ppr sorted_locs))] + where + sorted_locs = sortLt occ'ed_before (map nameSrcLoc (n:ns)) + occ'ed_before a b = LT == compare a b -dupExportWarn (occ_name, (_,_,times)) sty - = hsep [ppr sty occ_name, - ptext SLIT("mentioned"), text (speak_times (times+1)), - ptext SLIT("in export list")] +dupExportWarn occ_name ie1 ie2 + = hsep [quotes (ppr occ_name), + ptext SLIT("is exported by"), quotes (ppr ie1), + ptext SLIT("and"), quotes (ppr ie2)] -dupModuleExport mod times sty - = hsep [ptext SLIT("Module"), pprModule sty mod, - ptext SLIT("mentioned"), text (speak_times times), +dupModuleExport mod + = hsep [ptext SLIT("Duplicate"), + quotes (ptext SLIT("Module") <+> ppr mod), ptext SLIT("in export list")] -speak_times :: Int{- >=1 -} -> String -speak_times t | t == 1 = "once" - | t == 2 = "twice" - | otherwise = show t ++ " times" - - +moduleDeprec mod txt + = sep [ ptext SLIT("Module") <+> quotes (ppr mod) <+> ptext SLIT("is deprecated:"), + nest 4 (ppr txt) ] \end{code} -