X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Fcompiler%2Frename%2FRnNames.lhs;h=fc018e76ca4f097826e0710ee01a95a216cd14ea;hb=f1fdf769b432ca383b2033f5c973494905d225d1;hp=2bfe8a5c46d51bddf2c40efe8bbfe9bbf8ae28e9;hpb=cbdeae8fc8a1c72d20d89241acae8a313214b51c;p=ghc-hetmet.git diff --git a/ghc/compiler/rename/RnNames.lhs b/ghc/compiler/rename/RnNames.lhs index 2bfe8a5..fc018e7 100644 --- a/ghc/compiler/rename/RnNames.lhs +++ b/ghc/compiler/rename/RnNames.lhs @@ -5,137 +5,239 @@ \begin{code} module RnNames ( - getGlobalNames, exportsFromAvail + rnImports, mkRdrEnvAndImports, importsFromLocalDecls, + rnExports, mkExportNameSet, + getLocalDeclBinders, extendRdrEnvRn, + reportUnusedNames, reportDeprecations ) where #include "HsVersions.h" -import CmdLineOpts ( DynFlag(..) ) - -import HsSyn ( HsModule(..), HsDecl(..), IE(..), ieName, ImportDecl(..), - ForeignDecl(..), - collectLocatedHsBinders - ) -import RdrHsSyn ( RdrNameIE, RdrNameImportDecl, - RdrNameHsModule, RdrNameHsDecl - ) -import RnIfaces ( recordLocalSlurps ) -import RnHiFiles ( getTyClDeclBinders, loadInterface ) +import DynFlags ( DynFlag(..), GhcMode(..) ) +import HsSyn ( IE(..), ieName, ImportDecl(..), LImportDecl, + ForeignDecl(..), HsGroup(..), HsValBinds(..), + Sig(..), collectHsBindLocatedBinders, tyClDeclNames, + LIE ) import RnEnv -import RnMonad +import IfaceEnv ( ifaceExportNames ) +import LoadIface ( loadSrcInterface ) +import TcRnMonad hiding (LIE) import FiniteMap -import PrelNames ( pRELUDE_Name, mAIN_Name, main_RDR_Unqual, isUnboundName ) -import Module ( ModuleName, moduleName, WhereFrom(..) ) -import Name ( Name, nameSrcLoc, nameOccName ) +import PrelNames ( pRELUDE, isUnboundName, main_RDR_Unqual ) +import Module ( Module, moduleString, unitModuleEnv, + lookupModuleEnv, moduleEnvElts, foldModuleEnv ) +import Name ( Name, nameSrcLoc, nameOccName, nameModule, isWiredInName, + nameParent, nameParent_maybe, isExternalName, + isBuiltInSyntax ) import NameSet import NameEnv -import HscTypes ( Provenance(..), ImportReason(..), GlobalRdrEnv, - GenAvailInfo(..), AvailInfo, Avails, AvailEnv, - Deprecations(..), ModIface(..) +import OccName ( srcDataName, isTcOcc, pprNonVarNameSpace, + occNameSpace, + OccEnv, mkOccEnv, lookupOccEnv, emptyOccEnv, + extendOccEnv ) +import HscTypes ( GenAvailInfo(..), AvailInfo, + HomePackageTable, PackageIfaceTable, + unQualInScope, + Deprecs(..), ModIface(..), Dependencies(..), + lookupIface, ExternalPackageState(..) ) -import RdrName ( rdrNameOcc, setRdrNameOcc ) -import OccName ( setOccNameSpace, dataName ) -import NameSet ( elemNameSet, emptyNameSet ) +import Packages ( PackageIdH(..) ) +import RdrName ( RdrName, rdrNameOcc, setRdrNameSpace, + GlobalRdrEnv, mkGlobalRdrEnv, GlobalRdrElt(..), + emptyGlobalRdrEnv, plusGlobalRdrEnv, globalRdrEnvElts, + extendGlobalRdrEnv, lookupGlobalRdrEnv, unQualOK, lookupGRE_Name, + Provenance(..), ImportSpec(..), ImpDeclSpec(..), ImpItemSpec(..), + importSpecLoc, importSpecModule, isLocalGRE, pprNameProvenance ) import Outputable -import Maybes ( maybeToBool, catMaybes, mapMaybe ) -import ListSetOps ( removeDups ) -import Util ( sortLt ) +import Maybes ( isNothing, catMaybes, mapCatMaybes, seqMaybe, orElse ) +import SrcLoc ( Located(..), mkGeneralSrcSpan, + unLoc, noLoc, srcLocSpan, SrcSpan ) +import BasicTypes ( DeprecTxt ) +import DriverPhases ( isHsBoot ) +import Util ( notNull ) import List ( partition ) +import IO ( openFile, IOMode(..) ) \end{code} %************************************************************************ %* * -\subsection{Get global names} + rnImports %* * %************************************************************************ \begin{code} -getGlobalNames :: Module -> RdrNameHsModule - -> RnMG (GlobalRdrEnv, -- Maps all in-scope things - GlobalRdrEnv, -- Maps just *local* things - ExportAvails) -- The exported stuff - -getGlobalNames this_mod (HsModule _ _ _ imports decls _ mod_loc) - = -- PROCESS LOCAL DECLS - -- Do these *first* so that the correct provenance gets - -- into the global name cache. - importsFromLocalDecls this_mod decls `thenRn` \ (local_gbl_env, local_mod_avails) -> - - -- PROCESS IMPORT DECLS - -- Do the non {- SOURCE -} ones first, so that we get a helpful - -- warning for {- SOURCE -} ones that are unnecessary - doptRn Opt_NoImplicitPrelude `thenRn` \ opt_no_prelude -> - let - all_imports = mk_prel_imports opt_no_prelude ++ imports - (source, ordinary) = partition is_source_import all_imports - is_source_import (ImportDecl _ ImportByUserSource _ _ _ _) = True - is_source_import other = False - - get_imports = importsFromImportDecl this_mod_name - in - mapAndUnzipRn get_imports ordinary `thenRn` \ (imp_gbl_envs1, imp_avails_s1) -> - mapAndUnzipRn get_imports source `thenRn` \ (imp_gbl_envs2, imp_avails_s2) -> - - -- COMBINE RESULTS - -- We put the local env second, so that a local provenance - -- "wins", even if a module imports itself. - let - gbl_env :: GlobalRdrEnv - imp_gbl_env = foldr plusGlobalRdrEnv emptyRdrEnv (imp_gbl_envs2 ++ imp_gbl_envs1) - gbl_env = imp_gbl_env `plusGlobalRdrEnv` local_gbl_env - - all_avails :: ExportAvails - all_avails = foldr plusExportAvails local_mod_avails (imp_avails_s2 ++ imp_avails_s1) - in - - -- ALL DONE - returnRn (gbl_env, local_gbl_env, all_avails) +rnImports :: [LImportDecl RdrName] -> RnM [LImportDecl Name] +rnImports imports + -- PROCESS IMPORT DECLS + -- Do the non {- SOURCE -} ones first, so that we get a helpful + -- warning for {- SOURCE -} ones that are unnecessary + = do 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 = rnImportDecl this_mod + + stuff1 <- mapM get_imports ordinary + stuff2 <- mapM get_imports source + return (stuff1 ++ stuff2) + 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. + mk_prel_imports this_mod implicit_prelude + | this_mod == pRELUDE + || explicit_prelude_import + || not implicit_prelude + = [] + | otherwise = [preludeImportDecl] + explicit_prelude_import + = notNull [ () | L _ (ImportDecl mod _ _ _ _) <- imports, + unLoc mod == pRELUDE ] + +preludeImportDecl :: LImportDecl RdrName +preludeImportDecl + = L loc $ + ImportDecl (L loc pRELUDE) + False {- Not a boot interface -} + False {- Not qualified -} + Nothing {- No "as" -} + Nothing {- No import list -} where - this_mod_name = moduleName this_mod - - -- 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 no_prelude - | this_mod_name == pRELUDE_Name || - explicit_prelude_import || - no_prelude - = [] - - | otherwise = [ImportDecl pRELUDE_Name - ImportByUser - False {- Not qualified -} - Nothing {- No "as" -} - Nothing {- No import list -} - mod_loc] - - explicit_prelude_import - = not (null [ () | (ImportDecl mod _ _ _ _ _) <- imports, mod == pRELUDE_Name ]) + loc = mkGeneralSrcSpan FSLIT("Implicit import declaration") + +mkRdrEnvAndImports :: [LImportDecl Name] -> RnM (GlobalRdrEnv, ImportAvails) +mkRdrEnvAndImports imports + = do this_mod <- getModule + let get_imports = importsFromImportDecl this_mod + stuff <- mapM get_imports imports + let (imp_gbl_envs, imp_avails) = unzip stuff + 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) + \end{code} \begin{code} -importsFromImportDecl :: ModuleName - -> RdrNameImportDecl - -> RnMG (GlobalRdrEnv, - ExportAvails) +rnImportDecl :: Module + -> LImportDecl RdrName + -> RnM (LImportDecl Name) +rnImportDecl this_mod (L loc importDecl@(ImportDecl loc_imp_mod_name want_boot qual_only as_mod imp_details)) + = setSrcSpan loc $ + do iface <- loadSrcInterface doc imp_mod_name want_boot + let qual_mod_name = case as_mod of + Nothing -> imp_mod_name + Just another_name -> another_name + imp_spec = ImpDeclSpec { is_mod = imp_mod_name, is_qual = qual_only, + is_dloc = loc, is_as = qual_mod_name } + total_avails <- ifaceExportNames (mi_exports iface) + importDecl' <- rnImportDecl' iface imp_spec importDecl total_avails + return (L loc importDecl') + where imp_mod_name = unLoc loc_imp_mod_name + doc = ppr imp_mod_name <+> ptext SLIT("is directly imported") + +rnImportDecl' :: ModIface -> ImpDeclSpec -> ImportDecl RdrName -> NameSet -> RnM (ImportDecl Name) +rnImportDecl' iface decl_spec (ImportDecl mod_name want_boot qual_only as_mod Nothing) all_names + = return $ ImportDecl mod_name want_boot qual_only as_mod Nothing +rnImportDecl' iface decl_spec (ImportDecl mod_name want_boot qual_only as_mod (Just (want_hiding,import_items))) all_names + = do import_items_mbs <- mapM (srcSpanWrapper) import_items + let rn_import_items = concat . catMaybes $ import_items_mbs + return $ ImportDecl mod_name want_boot qual_only as_mod (Just (want_hiding,rn_import_items)) + where + srcSpanWrapper (L span ieRdr) + = setSrcSpan span $ + case get_item ieRdr of + Nothing + -> do addErr (badImportItemErr iface decl_spec ieRdr) + return Nothing + Just ieNames + -> return (Just [L span ie | ie <- ieNames]) + 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. -importsFromImportDecl this_mod_name (ImportDecl imp_mod_name from qual_only as_mod import_spec iloc) - = pushSrcLocRn iloc $ + sub_env :: NameEnv [Name] + sub_env = mkSubNameEnv all_names + + get_item :: IE RdrName -> Maybe [IE Name] + -- 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 _) + = Nothing + get_item (IEThingAll tc) + = do name <- check_name tc + return [IEThingAll name] + get_item (IEThingAbs tc) + | want_hiding -- hiding ( C ) + -- Here the 'C' can be a data constructor + -- *or* a type/class, or even both + = case catMaybes [check_name tc, check_name (setRdrNameSpace tc srcDataName)] of + [] -> Nothing + names -> return [ IEThingAbs n | n <- names ] + | otherwise + = do name <- check_name tc + return [IEThingAbs name] + get_item (IEThingWith n ns) -- import (C (A,B)) + = do name <- check_name n + let env = mkOccEnv [(nameOccName s, s) | s <- subNames sub_env name] + mb_names = map (lookupOccEnv env . rdrNameOcc) ns + names <- sequence mb_names + return [IEThingWith name names] + get_item (IEVar n) + = do name <- check_name n + return [IEVar name] + + check_name :: RdrName -> Maybe Name + check_name rdrName + = lookupOccEnv occ_env (rdrNameOcc rdrName) + + +importsFromImportDecl :: Module + -> LImportDecl Name + -> RnM (GlobalRdrEnv, ImportAvails) + +importsFromImportDecl this_mod + (L loc (ImportDecl loc_imp_mod_name want_boot qual_only as_mod imp_details)) + = + setSrcSpan loc $ - loadInterface (ppr imp_mod_name <+> ptext SLIT("is directly imported")) - imp_mod_name from `thenRn` \ iface -> + -- If there's an error in loadInterface, (e.g. interface + -- file not found) we get lots of spurious errors from 'filterImports' let - imp_mod = mi_module iface - avails_by_module = mi_exports iface - deprecs = mi_deprecs iface - - avails :: Avails - avails = [ avail | (mod_name, avails) <- avails_by_module, - mod_name /= this_mod_name, - avail <- avails ] + imp_mod_name = unLoc loc_imp_mod_name + doc = ppr imp_mod_name <+> ptext SLIT("is directly imported") + in + 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 ) + + -- 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 -- 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 @@ -153,250 +255,271 @@ importsFromImportDecl this_mod_name (ImportDecl imp_mod_name from qual_only as_m -- -- 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 = ImpDeclSpec { is_mod = imp_mod_name, is_qual = qual_only, + is_dloc = loc, is_as = qual_mod_name } in - if null avails_by_module then - -- If there's an error in loadInterface, (e.g. interface - -- file not found) we get lots of spurious errors from 'filterImports' - returnRn (emptyRdrEnv, mkEmptyExportAvails imp_mod_name) - else - - -- Complain if we import a deprecated module - ifOptRn Opt_WarnDeprecations ( - case deprecs of - DeprecAll txt -> addWarnRn (moduleDeprec imp_mod_name txt) - other -> returnRn () - ) `thenRn_` - - -- Filter the imports according to the import list - filterImports imp_mod_name from import_spec avails `thenRn` \ (filtered_avails, hides, explicits) -> - - let - unqual_imp = not qual_only -- Maybe want unqualified names - qual_mod = case as_mod of - Nothing -> imp_mod_name - Just another_name -> another_name - - mk_prov name = NonLocalDef (UserImport imp_mod iloc (name `elemNameSet` explicits)) - gbl_env = mkGlobalRdrEnv qual_mod unqual_imp True hides mk_prov filtered_avails deprecs - exports = mkExportAvails qual_mod unqual_imp gbl_env filtered_avails - in - returnRn (gbl_env, exports) -\end{code} + -- Get the total imports, and filter them according to the import list + ifaceExportNames filtered_exports `thenM` \ total_avails -> + filterImports iface imp_spec + imp_details total_avails `thenM` \ (avail_env, gbl_env) -> + getDOpts `thenM` \ dflags -> -\begin{code} -importsFromLocalDecls this_mod decls - = mapRn (getLocalDeclBinders this_mod) decls `thenRn` \ avails_s -> - -- The avails that are returned don't include the "system" names let - avails = concat avails_s + -- 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) + + -- True <=> import M () + import_all = case imp_details of + Just (is_hiding, ls) -> not is_hiding && null ls + other -> False + + -- unqual_avails is the Avails that are visible in *unqualified* form + -- We need to know this so we know what to export when we see + -- 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 } - all_names :: [Name] -- All the defns; no dups eliminated - all_names = [name | avail <- avails, name <- availNames avail] - - dups :: [[Name]] - (_, dups) = removeDups compare all_names in - -- Check for duplicate definitions - -- The complaint will come out as "Multiple declarations of Foo.f" because - -- since 'f' is in the env twice, the unQualInScope used by the error-msg - -- printer returns False. It seems awkward to fix, unfortunately. - mapRn_ (addErrRn . dupDeclErr) dups `thenRn_` - - - -- Record that locally-defined things are available - recordLocalSlurps (availsToNameSet avails) `thenRn_` - let - mod_name = moduleName this_mod - unqual_imp = True -- Want unqualified names - mk_prov n = LocalDef -- Provenance is local - hides = [] -- Hide nothing + -- Complain if we import a deprecated module + ifOptM Opt_WarnDeprecations ( + case deprecs of + DeprecAll txt -> addWarn (moduleDeprec imp_mod_name txt) + other -> returnM () + ) `thenM_` - gbl_env = mkGlobalRdrEnv mod_name unqual_imp True hides mk_prov avails NoDeprecs - -- NoDeprecs: don't complain about 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 + returnM (gbl_env, imports) - exports = mkExportAvails mod_name unqual_imp gbl_env avails - in - returnRn (gbl_env, exports) - ---------------------------- -getLocalDeclBinders :: Module -> RdrNameHsDecl -> RnMG [AvailInfo] -getLocalDeclBinders mod (TyClD tycl_decl) - = -- 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. - getTyClDeclBinders mod tycl_decl `thenRn` \ (avail, sys_names) -> - - -- Record that the system names are available - recordLocalSlurps (mkNameSet sys_names) `thenRn_` - returnRn [avail] - -getLocalDeclBinders mod (ValD binds) - = mapRn new (collectLocatedHsBinders binds) `thenRn` \ avails -> - returnRn avails - where - new (rdr_name, loc) = newTopBinder mod rdr_name loc `thenRn` \ name -> - returnRn (Avail name) - -getLocalDeclBinders mod (ForD (ForeignImport nm _ _ loc)) - = newTopBinder mod nm loc `thenRn` \ name -> - returnRn [Avail name] -getLocalDeclBinders mod (ForD _) - = returnRn [] - -getLocalDeclBinders mod (FixD _) = returnRn [] -getLocalDeclBinders mod (DeprecD _) = returnRn [] -getLocalDeclBinders mod (DefD _) = returnRn [] -getLocalDeclBinders mod (InstD _) = returnRn [] -getLocalDeclBinders mod (RuleD _) = returnRn [] +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 :: ModuleName -- The module being imported - -> WhereFrom -- Tells whether it's a {-# SOURCE #-} import - -> Maybe (Bool, [RdrNameIE]) -- Import spec; True => hiding - -> [AvailInfo] -- What's available - -> RnMG ([AvailInfo], -- What's actually imported - [AvailInfo], -- What's to be hidden - -- (the unqualified version, that is) - -- (We need to return both the above sets, because - -- the qualified version is never hidden; so we can't - -- implement hiding by reducing what's imported.) - NameSet) -- What was imported explicitly - - -- Complains if import spec mentions things that the module doesn't export - -- Warns/informs if import spec contains duplicates. -filterImports mod from Nothing imports - = returnRn (imports, [], emptyNameSet) - -filterImports mod from (Just (want_hiding, import_items)) total_avails - = flatMapRn get_item import_items `thenRn` \ avails_w_explicits -> - let - (item_avails, explicits_s) = unzip avails_w_explicits - explicits = foldl addListToNameSet emptyNameSet explicits_s - in - if want_hiding - then - -- All imported; item_avails to be hidden - returnRn (total_avails, item_avails, emptyNameSet) - else - -- Just item_avails imported; nothing to be hidden - returnRn (item_avails, [], explicits) +importsFromLocalDecls :: HsGroup RdrName -> RnM TcGblEnv +importsFromLocalDecls group + = do { gbl_env <- getGblEnv + + ; names <- getLocalDeclBinders gbl_env group + + ; implicit_prelude <- doptM Opt_ImplicitPrelude + ; let { + -- Optimisation: filter out names for built-in syntax + -- They just clutter up the environment (esp tuples), and the parser + -- will generate Exact RdrNames for them, so the cluttered + -- 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 = names + | otherwise = filter (not . isBuiltInSyntax) names ; + + ; this_mod = tcg_mod gbl_env + ; imports = emptyImportAvails { + imp_env = unitModuleEnv this_mod $ + mkNameSet filtered_names + } + } + + ; rdr_env' <- extendRdrEnvRn (tcg_rdr_env gbl_env) names + + ; returnM (gbl_env { tcg_rdr_env = rdr_env', + tcg_imports = imports `plusImportAvails` tcg_imports gbl_env }) + } + +extendRdrEnvRn :: GlobalRdrEnv -> [Name] -> RnM GlobalRdrEnv +-- Add the new locally-bound names one by one, checking for duplicates as +-- we do so. Remember that in Template Haskell the duplicates +-- might *already be* in the GlobalRdrEnv from higher up the module +extendRdrEnvRn rdr_env names + = foldlM add_local rdr_env names where - import_fm :: FiniteMap OccName AvailInfo - import_fm = listToFM [ (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 = addErrRn (badImportItemErr mod from item) `thenRn_` - returnRn [] - - get_item item@(IEModuleContents _) = bale_out item - - get_item item@(IEThingAll _) - = 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 - ifOptRn Opt_WarnMisc (addWarnRn (dodgyImportWarn mod item)) `thenRn_` - returnRn [(avail, [availName avail])] - Just avail -> returnRn [(avail, [availName 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 (IEThingAbs data_n)] of - [] -> bale_out item - avails -> returnRn [(a, []) | a <- avails] - -- The 'explicits' list is irrelevant when hiding - where - data_n = setRdrNameOcc n (setOccNameSpace (rdrNameOcc n) dataName) - - get_item item - = case check_item item of - Nothing -> bale_out item - Just avail -> returnRn [(avail, availNames avail)] + add_local rdr_env name + | gres <- lookupGlobalRdrEnv rdr_env (nameOccName name) + , (dup_gre:_) <- filter isLocalGRE gres -- Check for existing *local* defns + = do { addDupDeclErr (gre_name dup_gre) name + ; return rdr_env } + | otherwise + = return (extendGlobalRdrEnv rdr_env new_gre) + where + new_gre = GRE {gre_name = name, gre_prov = LocalDef} +\end{code} - check_item item - | not (maybeToBool maybe_in_import_avails) || - not (maybeToBool maybe_filtered_avail) - = Nothing +@getLocalDeclBinders@ returns the names for an @HsDecl@. It's +used for source code. - | otherwise - = Just filtered_avail - - where - wanted_occ = rdrNameOcc (ieName item) - maybe_in_import_avails = lookupFM import_fm wanted_occ + *** See "THE NAMING STORY" in HsDecls **** - Just avail = maybe_in_import_avails - maybe_filtered_avail = filterAvail item avail - Just filtered_avail = maybe_filtered_avail +\begin{code} +getLocalDeclBinders :: TcGblEnv -> HsGroup RdrName -> RnM [Name] +getLocalDeclBinders gbl_env (HsGroup {hs_valds = ValBindsIn val_decls val_sigs, + hs_tyclds = tycl_decls, + hs_fords = foreign_decls }) + = do { tc_names_s <- mappM new_tc tycl_decls + ; val_names <- mappM new_simple val_bndrs + ; return (foldr (++) val_names tc_names_s) } + where + mod = tcg_mod gbl_env + is_hs_boot = isHsBoot (tcg_src gbl_env) ; + val_bndrs | is_hs_boot = sig_hs_bndrs + | otherwise = for_hs_bndrs ++ val_hs_bndrs + -- In a hs-boot file, the value binders come from the + -- *signatures*, and there should be no foreign binders + + new_simple rdr_name = newTopSrcBinder mod Nothing rdr_name + + sig_hs_bndrs = [nm | L _ (TypeSig nm _) <- val_sigs] + val_hs_bndrs = collectHsBindLocatedBinders val_decls + for_hs_bndrs = [nm | L _ (ForeignImport nm _ _ _) <- foreign_decls] + + new_tc tc_decl + = do { main_name <- newTopSrcBinder mod Nothing main_rdr + ; sub_names <- mappM (newTopSrcBinder mod (Just main_name)) sub_rdrs + ; return (main_name : sub_names) } + where + (main_rdr : sub_rdrs) = tyClDeclNames (unLoc tc_decl) \end{code} - %************************************************************************ %* * -\subsection{Qualifiying imports} +\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} -mkEmptyExportAvails :: ModuleName -> ExportAvails -mkEmptyExportAvails mod_name = (unitFM mod_name [], emptyNameEnv) +filterImports :: ModIface + -> ImpDeclSpec -- The span for the entire import decl + -> Maybe (Bool, [LIE Name]) -- Import spec; True => hiding + -> NameSet -- What's available + -> RnM (NameSet, -- What's imported (qualified or unqualified) + GlobalRdrEnv) -- Same again, but in GRE form -mkExportAvails :: ModuleName -> Bool -> GlobalRdrEnv -> [AvailInfo] -> ExportAvails -mkExportAvails mod_name unqual_imp gbl_env avails - = (mod_avail_env, entity_avail_env) + -- Complains if import spec mentions things that the module doesn't export + -- Warns/informs if import spec contains duplicates. + +mkGenericRdrEnv decl_spec names + = mkGlobalRdrEnv [ GRE { gre_name = name, gre_prov = Imported [imp_spec] } + | name <- nameSetToList names ] where - mod_avail_env = unitFM mod_name unqual_avails - - -- unqual_avails is the Avails that are visible in *unqualfied* form - -- (1.4 Report, Section 5.1.1) - -- For example, in - -- import T hiding( f ) - -- we delete f from avails - - unqual_avails | not unqual_imp = [] -- Short cut when no unqualified imports - | otherwise = mapMaybe prune avails - - prune (Avail n) | unqual_in_scope n = Just (Avail n) - prune (Avail n) | otherwise = Nothing - prune (AvailTC n ns) | null uqs = Nothing - | otherwise = Just (AvailTC n uqs) - where - uqs = filter unqual_in_scope ns - - unqual_in_scope n = unQualInScope gbl_env n + imp_spec = ImpSpec { is_decl = decl_spec, is_item = ImpAll } + +filterImports iface decl_spec Nothing all_names + = return (all_names, mkGenericRdrEnv decl_spec all_names) + +filterImports iface decl_spec (Just (want_hiding, import_items)) all_names + = mapM (addLocM get_item) import_items >>= \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 decl_spec pruned_avails) + where + sub_env :: NameEnv [Name] -- Classify each name by its parent + sub_env = mkSubNameEnv all_names - entity_avail_env = mkNameEnv [ (name,avail) | avail <- avails, - name <- availNames avail] + 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 [imp_spec] } + where + imp_spec = ImpSpec { is_decl = decl_spec, is_item = item_spec } + item_spec = ImpSome { is_explicit = explicit, is_iloc = loc } + explicit = all_explicit || isNothing (nameParent_maybe name) + + get_item :: IE Name -> 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 _) + -- This case should be filtered out by 'rnImports'. + = panic "filterImports: IEModuleContents?" + + get_item (IEThingAll name) + = case subNames sub_env name of + [] -> -- This occurs when you import T(..), but + -- only export T abstractly. + do ifOptM Opt_WarnDodgyImports (addWarn (dodgyImportWarn name)) + succeed_with False [name] + names -> succeed_with False (name:names) + + get_item (IEThingAbs name) + = succeed_with True [name] + + get_item (IEThingWith name names) + = succeed_with True (name:names) + get_item (IEVar name) + = succeed_with True [name] -plusExportAvails :: ExportAvails -> ExportAvails -> ExportAvails -plusExportAvails (m1, e1) (m2, e2) - = (plusFM_C (++) m1 m2, plusAvailEnv e1 e2) - -- ToDo: wasteful: we do this once for each constructor! \end{code} @@ -408,133 +531,540 @@ plusExportAvails (m1, e1) (m2, e2) 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). +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... +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} type ExportAccum -- The type of the accumulating parameter of - -- the main worker function in exportsFromAvail - = ([ModuleName], -- 'module M's seen so far + -- the main worker function in rnExports + = ([Module], -- '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 + NameSet) -- The accumulated exported stuff +emptyExportAccum = ([], emptyOccEnv, emptyNameSet) -type ExportOccMap = FiniteMap OccName (Name, RdrNameIE) +type ExportOccMap = OccEnv (Name, IE Name) -- 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 :: ModuleName - -> Maybe [RdrNameIE] -- Export spec - -> ExportAvails - -> GlobalRdrEnv - -> RnMG Avails +rnExports :: Maybe [LIE RdrName] + -> RnM (Maybe [LIE Name]) +rnExports Nothing = return Nothing +rnExports (Just exports) + = do TcGblEnv { tcg_imports = ImportAvails { imp_env = imp_env } } <- getGblEnv + let sub_env :: NameEnv [Name] -- Classify each name by its parent + sub_env = mkSubNameEnv (foldModuleEnv unionNameSets emptyNameSet imp_env) + inLoc fn (L span x) + = do x' <- fn x + return (L span x') + rnExport (IEVar rdrName) + = do name <- lookupGlobalOccRn rdrName + return (IEVar name) + rnExport (IEThingAbs rdrName) + = do name <- lookupGlobalOccRn rdrName + return (IEThingAbs name) + rnExport (IEThingAll rdrName) + = do name <- lookupGlobalOccRn rdrName + return (IEThingAll name) + rnExport (IEThingWith rdrName rdrNames) + = do name <- lookupGlobalOccRn rdrName + let env = mkOccEnv [(nameOccName s, s) | s <- subNames sub_env name] + mb_names = map (lookupOccEnv env . rdrNameOcc) rdrNames + if any isNothing mb_names + then -- The export error will be reporting in 'mkExportNameSet' + return (IEThingWith name []) + else return (IEThingWith name (catMaybes mb_names)) + rnExport (IEModuleContents mod) + = return (IEModuleContents mod) + rn_exports <- mapM (inLoc rnExport) exports + return (Just rn_exports) + +mkExportNameSet :: Bool -- False => no 'module M(..) where' header at all + -> Maybe [LIE Name] -- 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 global_name_env - = exportsFromAvail this_mod true_exports export_avails global_name_env - where - true_exports = Just $ if this_mod == mAIN_Name - then [IEVar main_RDR_Unqual] - -- export Main.main *only* unless otherwise specified, - else [IEModuleContents this_mod] - -- but for all other modules export everything. - -exportsFromAvail this_mod (Just export_items) - (mod_avail_env, entity_avail_env) - global_name_env - = doptRn Opt_WarnDuplicateExports `thenRn` \ warn_dup_exports -> - foldlRn (exports_from_item warn_dup_exports) - ([], emptyFM, emptyAvailEnv) export_items - `thenRn` \ (_, _, export_avail_map) -> - let - export_avails :: [AvailInfo] - export_avails = nameEnvElts export_avail_map - in - returnRn export_avails +mkExportNameSet 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 + ghc_mode <- getGhcMode + real_exports <- case () of + () | explicit_mod + -> return exports + | ghc_mode == Interactive + -> return Nothing + | otherwise + -> do mainName <- lookupGlobalOccRn main_RDR_Unqual + return (Just [noLoc (IEVar mainName)]) + -- ToDo: the 'noLoc' here is unhelpful if 'main' turns out to be out of scope + 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 }) + = do (_, _, exports) <- foldlM do_litem emptyExportAccum items + return exports where - exports_from_item :: Bool -> ExportAccum -> RdrNameIE -> RnMG ExportAccum + sub_env :: NameEnv [Name] -- Classify each name by its parent + sub_env = mkSubNameEnv (foldModuleEnv unionNameSets emptyNameSet imp_env) - exports_from_item warn_dups acc@(mods, occs, avails) ie@(IEModuleContents mod) + do_litem :: ExportAccum -> LIE Name -> RnM ExportAccum + do_litem acc = addLocM (exports_from_item acc) + + exports_from_item :: ExportAccum -> IE Name -> RnM ExportAccum + exports_from_item acc@(mods, occs, exports) ie@(IEModuleContents mod) | mod `elem` mods -- Duplicate export of M - = warnCheckRn warn_dups (dupModuleExport mod) `thenRn_` - returnRn acc + = do { warn_dup_exports <- doptM Opt_WarnDuplicateExports ; + warnIf warn_dup_exports (dupModuleExport mod) ; + returnM acc } | otherwise - = case lookupFM mod_avail_env mod of - Nothing -> failWithRn acc (modExportErr mod) - Just mod_avails -> foldlRn (check_occs ie) occs mod_avails - `thenRn` \ occs' -> - let - avails' = foldl addAvail avails mod_avails - in - returnRn (mod:mods, occs', avails') - - exports_from_item warn_dups acc@(mods, occs, avails) ie - = lookupSrcName global_name_env (ieName ie) `thenRn` \ name -> - - -- See what's available in the current environment - case lookupNameEnv entity_avail_env name of { - Nothing -> -- Presumably this happens because lookupSrcName didn't find - -- the name and returned an unboundName, which won't be in - -- the entity_avail_env, of course - WARN( not (isUnboundName name), ppr name ) - returnRn acc ; - - Just avail -> - - -- Filter out the bits we want - case filterAvail ie avail of { - Nothing -> -- Not enough availability - failWithRn acc (exportItemErr ie) ; - - Just export_avail -> - - -- Phew! It's OK! Now to check the occurrence stuff! - warnCheckRn (ok_item ie avail) (dodgyExportWarn ie) `thenRn_` - check_occs ie occs export_avail `thenRn` \ occs' -> - returnRn (mods, occs', addAvail avails export_avail) - }} - - - -ok_item (IEThingAll _) (AvailTC _ [n]) = False - -- This occurs when you import T(..), but - -- only export T abstractly. The single [n] - -- in the AvailTC is the type or class itself -ok_item _ _ = True - -check_occs :: RdrNameIE -> ExportOccMap -> AvailInfo -> RnMG ExportOccMap -check_occs ie occs avail - = doptRn Opt_WarnDuplicateExports `thenRn` \ warn_dup_exports -> - foldlRn (check warn_dup_exports) occs (availNames avail) + = case lookupModuleEnv imp_env mod of + Nothing -> do addErr (modExportErr mod) + return acc + Just names + -> do let new_exports = filterNameSet (inScopeUnqual rdr_env) names + -- 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. + occs' <- check_occs ie occs (nameSetToList new_exports) + return (mod:mods, occs', exports `unionNameSets` new_exports) + + exports_from_item acc@(mods, occs, exports) ie + = if isUnboundName (ieName ie) + then return acc -- Avoid error cascade + else let new_exports = filterAvail ie sub_env in + do checkErr (not (null new_exports)) (exportItemErr ie) + checkForDodgyExport ie new_exports + occs' <- check_occs ie occs new_exports + return (mods, occs', addListToNameSet exports new_exports) + +------------------------------- +filterAvail :: IE Name -- Wanted + -> NameEnv [Name] -- Maps type/class names to their sub-names + -> [Name] + +filterAvail (IEVar n) subs = [n] +filterAvail (IEThingAbs n) subs = [n] +filterAvail (IEThingAll n) subs = n : subNames subs n +filterAvail (IEThingWith n ns) subs = n : ns +filterAvail (IEModuleContents _) _ = panic "filterAvail" + +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 - check warn_dup occs name - = case lookupFM occs name_occ of - Nothing -> returnRn (addToFM occs name_occ (name, ie)) - Just (name', ie') - | name == name' -> -- Duplicate export - warnCheckRn warn_dup - (dupExportWarn name_occ ie ie') - `thenRn_` returnRn occs + 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 Name -> [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 Name -> 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)) - | otherwise -> -- Same occ name but different names: an error - failWithRn occs (exportClashErr name_occ ie 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 + -- By this time, typechecking is complete, + -- so the PIT is fully populated + ; mapM_ (check hpt (eps_PIT eps)) all_gres } + where + used_names = allUses (tcg_dus tcg_env) + -- Report on all deprecated uses; hence allUses + all_gres = globalRdrEnvElts (tcg_rdr_env tcg_env) + + check hpt pit (GRE {gre_name = name, gre_prov = Imported (imp_spec:_)}) + | name `elemNameSet` used_names + , Just deprec_txt <- lookupDeprec hpt pit name + = setSrcSpan (importSpecLoc imp_spec) $ + addWarn (sep [ptext SLIT("Deprecated use of") <+> + pprNonVarNameSpace (occNameSpace (nameOccName name)) <+> + quotes (ppr name), + (parens imp_msg) <> colon, + (ppr deprec_txt) ]) + where + name_mod = nameModule name + imp_mod = importSpecModule imp_spec + imp_msg = ptext SLIT("imported from") <+> ppr imp_mod <> extra + extra | imp_mod == name_mod = empty + | otherwise = ptext SLIT(", but defined in") <+> ppr name_mod + + 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 [LIE RdrName] -- Export list + -> TcGblEnv -> RnM () +reportUnusedNames export_decls gbl_env + = do { traceRn ((text "RUN") <+> (ppr (tcg_dus gbl_env))) + ; warnUnusedTopBinds unused_locals + ; warnUnusedModules unused_imp_mods + ; warnUnusedImports unused_imports + ; warnDuplicateImports defined_and_used + ; printMinimalImports minimal_imports } + where + used_names, all_used_names :: NameSet + used_names = findUses (tcg_dus gbl_env) emptyNameSet + -- NB: currently, if f x = g, we only treat 'g' as used if 'f' is used + -- Hence findUses + + all_used_names = used_names `unionNameSets` + mkNameSet (mapCatMaybes nameParent_maybe (nameSetToList used_names)) + -- A use of C implies a use of T, + -- 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 + + -- 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}) + = not (all (module_unused . importSpecModule) imp_specs) + && or [exp | ImpSpec { is_item = ImpSome { is_explicit = exp } } <- imp_specs] + -- Don't complain about unused imports if we've already said the + -- entire import is unused + unused_imp other = False + + -- 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 (importSpecModule (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, 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,no_imp,loc) <- direct_import_mods, + not (mod `elemFM` minimal_imports1), + mod /= pRELUDE, + not no_imp] + -- The not no_imp 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 () +-- Given the GREs for names that are used, figure out which imports +-- could be omitted without changing the top-level environment. +-- +-- NB: Given import Foo( T ) +-- import qualified Foo +-- we do not report a duplicate import, even though Foo.T is brought +-- into scope by both, because there's nothing you can *omit* without +-- changing the top-level environment. So we complain only if it's +-- explicitly named in both imports or neither. +-- +-- Furthermore, we complain about Foo.T only if +-- there is no complaint about (unqualified) T + +warnDuplicateImports gres + = ifOptM Opt_WarnUnusedImports $ + sequenceM_ [ warn name pr + -- The 'head' picks the first offending group + -- for this particular name + | GRE { gre_name = name, gre_prov = Imported imps } <- gres + , pr <- redundants imps ] + where + warn name (red_imp, cov_imp) + = addWarnAt (importSpecLoc red_imp) + (vcat [ptext SLIT("Redundant import of:") <+> quotes pp_name, + ptext SLIT("It is also") <+> ppr cov_imp]) + where + pp_name | is_qual red_decl = ppr (is_as red_decl) <> dot <> ppr occ + | otherwise = ppr occ + occ = nameOccName name + red_decl = is_decl red_imp + + redundants :: [ImportSpec] -> [(ImportSpec,ImportSpec)] + -- The returned pair is (redundant-import, covering-import) + redundants imps + = [ (red_imp, cov_imp) + | red_imp <- imps + , cov_imp <- take 1 (filter (covers red_imp) imps) ] + + -- "red_imp" is a putative redundant import + -- "cov_imp" potentially covers it + -- This test decides whether red_imp could be dropped + -- + -- NOTE: currently the test does not warn about + -- import M( x ) + -- imoprt N( x ) + -- even if the same underlying 'x' is involved, because dropping + -- either import would change the qualified names in scope (M.x, N.x) + -- But if the qualified names aren't used, the import is indeed redundant + -- Sadly we don't know that. Oh well. + covers red_imp@(ImpSpec { is_decl = red_decl, is_item = red_item }) + cov_imp@(ImpSpec { is_decl = cov_decl, is_item = cov_item }) + | red_loc == cov_loc + = False -- Ignore diagonal elements + | not (is_as red_decl == is_as cov_decl) + = False -- They bring into scope different qualified names + | not (is_qual red_decl) && is_qual cov_decl + = False -- Covering one doesn't bring unqualified name into scope + | red_selective + = not cov_selective -- Redundant one is selective and covering one isn't + || red_later -- Both are explicit; tie-break using red_later + | otherwise + = not cov_selective -- Neither import is selective + && (is_mod red_decl == is_mod cov_decl) -- They import the same module + && red_later -- Tie-break + where + red_loc = importSpecLoc red_imp + cov_loc = importSpecLoc cov_imp + red_later = red_loc > cov_loc + cov_selective = selectiveImpItem cov_item + red_selective = selectiveImpItem red_item + +selectiveImpItem :: ImpItemSpec -> Bool +selectiveImpItem ImpAll = False +selectiveImpItem (ImpSome {}) = True + +-- ToDo: deal with original imports with 'qualified' and 'as M' clauses +printMinimalImports :: FiniteMap Module AvailEnv -- Minimal imports + -> 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 + mkFilename this_mod = moduleString 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) = do ies <- mapM to_ie (availEnvElts avail_env) + 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} @@ -542,19 +1072,18 @@ check_occs ie occs avail %************************************************************************ \begin{code} -badImportItemErr mod from ie - = sep [ptext SLIT("Module"), quotes (ppr mod), source_import, +badImportItemErr iface decl_spec ie + = sep [ptext SLIT("Module"), quotes (ppr (is_mod decl_spec)), source_import, ptext SLIT("does not export"), quotes (ppr ie)] where - source_import = case from of - ImportByUserSource -> ptext SLIT("(hi-boot interface)") - other -> empty + source_import | mi_boot iface = ptext SLIT("(hi-boot interface)") + | otherwise = empty -dodgyImportWarn mod item = dodgyMsg (ptext SLIT("import")) item -dodgyExportWarn item = dodgyMsg (ptext SLIT("export")) item +dodgyImportWarn item = dodgyMsg (ptext SLIT("import")) item +dodgyExportWarn item = dodgyMsg (ptext SLIT("export")) item -dodgyMsg kind item@(IEThingAll tc) - = sep [ ptext SLIT("The") <+> kind <+> ptext SLIT("item") <+> quotes (ppr 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") ] @@ -565,17 +1094,31 @@ 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 occ_name ie1 ie2 - = 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)] - -dupDeclErr (n:ns) - = vcat [ptext SLIT("Multiple declarations of") <+> quotes (ppr n), - nest 4 (vcat (map ppr sorted_locs))] +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 -> Name -> TcRn () +addDupDeclErr name_a name_b + = addErrAt (srcLocSpan loc2) $ + vcat [ptext SLIT("Multiple declarations of") <+> quotes (ppr name1), + ptext SLIT("Declared at:") <+> vcat [ppr (nameSrcLoc name1), ppr loc2]] where - sorted_locs = sortLt occ'ed_before (map nameSrcLoc (n:ns)) - occ'ed_before a b = LT == compare a b + loc2 = nameSrcLoc name2 + (name1,name2) | nameSrcLoc name_a > nameSrcLoc name_b = (name_b,name_a) + | otherwise = (name_a,name_b) + -- Report the error at the later location dupExportWarn occ_name ie1 ie2 = hsep [quotes (ppr occ_name),