+++ /dev/null
-%
-% (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
-%
-\section[RnNames]{Extracting imported and top-level names in scope}
-
-\begin{code}
-module RnNames (
- rnImports, mkRdrEnvAndImports, importsFromLocalDecls,
- rnExports, mkExportNameSet,
- getLocalDeclBinders, extendRdrEnvRn,
- reportUnusedNames, reportDeprecations
- ) where
-
-#include "HsVersions.h"
-
-import DynFlags ( DynFlag(..), GhcMode(..) )
-import HsSyn ( IE(..), ieName, ImportDecl(..), LImportDecl,
- ForeignDecl(..), HsGroup(..), HsValBinds(..),
- Sig(..), collectHsBindLocatedBinders, tyClDeclNames,
- LIE )
-import RnEnv
-import IfaceEnv ( ifaceExportNames )
-import LoadIface ( loadSrcInterface )
-import TcRnMonad hiding (LIE)
-
-import FiniteMap
-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 OccName ( srcDataName, isTcOcc, pprNonVarNameSpace,
- occNameSpace,
- OccEnv, mkOccEnv, lookupOccEnv, emptyOccEnv,
- extendOccEnv )
-import HscTypes ( GenAvailInfo(..), AvailInfo,
- HomePackageTable, PackageIfaceTable,
- unQualInScope,
- Deprecs(..), ModIface(..), Dependencies(..),
- lookupIface, ExternalPackageState(..)
- )
-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 ( 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}
-
-
-
-%************************************************************************
-%* *
- rnImports
-%* *
-%************************************************************************
-
-\begin{code}
-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
- 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}
-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.
-
- 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 $
-
- -- If there's an error in loadInterface, (e.g. interface
- -- file not found) we get lots of spurious errors from 'filterImports'
- let
- 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
- -- 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 = ImpDeclSpec { is_mod = imp_mod_name, is_qual = qual_only,
- is_dloc = loc, is_as = qual_mod_name }
- in
- -- Get the total imports, and filter them according to the import list
- ifaceExportNames filtered_exports `thenM` \ total_avails ->
- filterImports iface imp_spec
- imp_details total_avails `thenM` \ (avail_env, gbl_env) ->
-
- getDOpts `thenM` \ dflags ->
-
- let
- -- 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 }
-
- 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)
-
-warnRedundantSourceImport mod_name
- = ptext SLIT("Unnecessary {- SOURCE -} in the import of module")
- <+> quotes (ppr mod_name)
-\end{code}
-
-
-%************************************************************************
-%* *
- importsFromLocalDecls
-%* *
-%************************************************************************
-
-From the top-level declarations of this module produce
- * the lexical environment
- * the ImportAvails
-created by its bindings.
-
-Complain about duplicate bindings
-
-\begin{code}
-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
- 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}
-
-@getLocalDeclBinders@ returns the names for an @HsDecl@. It's
-used for source code.
-
- *** See "THE NAMING STORY" in HsDecls ****
-
-\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{Filtering imports}
-%* *
-%************************************************************************
-
-@filterImports@ takes the @ExportEnv@ telling what the imported module makes
-available, and filters it through the import spec (if any).
-
-\begin{code}
-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
-
- -- 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
- 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
-
- 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]
-
-\end{code}
-
-
-%************************************************************************
-%* *
-\subsection{Export list processing}
-%* *
-%************************************************************************
-
-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...
-
-\begin{code}
-type ExportAccum -- The type of the accumulating parameter of
- -- the main worker function in rnExports
- = ([Module], -- 'module M's seen so far
- ExportOccMap, -- Tracks exported occurrence names
- NameSet) -- The accumulated exported stuff
-emptyExportAccum = ([], emptyOccEnv, emptyNameSet)
-
-type ExportOccMap = OccEnv (Name, IE RdrName)
- -- Tracks what a particular exported OccName
- -- in an export list refers to, and which item
- -- it came from. It's illegal to export two distinct things
- -- that have the same occurrence name
-
-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)
- 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 ie@(IEThingWith rdrName rdrNames)
- = do name <- lookupGlobalOccRn rdrName
- if isUnboundName name
- then return (IEThingWith name [])
- else do
- let env = mkOccEnv [(nameOccName s, s) | s <- subNames sub_env name]
- mb_names = map (lookupOccEnv env . rdrNameOcc) rdrNames
- if any isNothing mb_names
- then do addErr (exportItemErr ie)
- return (IEThingWith name [])
- else return (IEThingWith name (catMaybes mb_names))
- rnExport (IEModuleContents mod)
- = return (IEModuleContents mod)
- rn_exports <- mapM (wrapLocM rnExport) exports
- return (Just rn_exports)
-
-mkExportNameSet :: Bool -- False => no 'module M(..) where' header at all
- -> Maybe ([LIE Name], [LIE RdrName]) -- Nothing => no explicit export list
- -> RnM NameSet
- -- Complains if two distinct exports have same OccName
- -- Warns about identical exports.
- -- Complains about exports items not in scope
-
-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)]
- ,[noLoc (IEVar main_RDR_Unqual)]))
- -- ToDo: the 'noLoc' here is unhelpful if 'main' turns out to be out of scope
- exports_from_avail real_exports rdr_env imports
-
-
-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,origItems)) rdr_env (ImportAvails { imp_env = imp_env })
- = do (_, _, exports) <- foldlM do_litem emptyExportAccum (zip items origItems)
- return exports
- where
- sub_env :: NameEnv [Name] -- Classify each name by its parent
- sub_env = mkSubNameEnv (foldModuleEnv unionNameSets emptyNameSet imp_env)
-
- do_litem :: ExportAccum -> (LIE Name, LIE RdrName) -> RnM ExportAccum
- do_litem acc (ieName, ieRdr)
- = addLocM (exports_from_item acc (unLoc ieRdr)) ieName
-
- exports_from_item :: ExportAccum -> IE RdrName -> IE Name -> RnM ExportAccum
- exports_from_item acc@(mods, occs, exports) ieRdr@(IEModuleContents mod) ie
- | mod `elem` mods -- Duplicate export of M
- = do { warn_dup_exports <- doptM Opt_WarnDuplicateExports ;
- warnIf warn_dup_exports (dupModuleExport mod) ;
- returnM acc }
-
- | otherwise
- = case lookupModuleEnv imp_env mod of
- Nothing -> 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 ieRdr occs (nameSetToList new_exports)
- return (mod:mods, occs', exports `unionNameSets` new_exports)
-
- exports_from_item acc@(mods, occs, exports) ieRdr ie
- = if isUnboundName (ieName ie)
- then return acc -- Avoid error cascade
- else let new_exports = filterAvail ie sub_env in
- do -- checkErr (not (null (drop 1 new_exports))) (exportItemErr ie)
- checkForDodgyExport ie new_exports
- occs' <- check_occs ieRdr 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
- 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 RdrName -> ExportOccMap -> [Name] -> RnM ExportOccMap
-check_occs ie occs names
- = foldlM check occs names
- where
- check occs name
- = case lookupOccEnv occs name_occ of
- Nothing -> returnM (extendOccEnv occs name_occ (name, ie))
-
- Just (name', ie')
- | name == name' -- Duplicate export
- -> do { warn_dup_exports <- doptM Opt_WarnDuplicateExports ;
- warnIf warn_dup_exports (dupExportWarn name_occ ie ie') ;
- returnM occs }
-
- | otherwise -- Same occ name but different names: an error
- -> do { global_env <- getGlobalRdrEnv ;
- addErr (exportClashErr global_env name name' ie ie') ;
- returnM occs }
- where
- name_occ = nameOccName name
-\end{code}
-
-%*********************************************************
-%* *
- Deprecations
-%* *
-%*********************************************************
-
-\begin{code}
-reportDeprecations :: TcGblEnv -> RnM ()
-reportDeprecations tcg_env
- = ifOptM Opt_WarnDeprecations $
- do { (eps,hpt) <- getEpsAndHpt
- -- 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}
-%* *
-%************************************************************************
-
-\begin{code}
-badImportItemErr iface decl_spec ie
- = sep [ptext SLIT("Module"), quotes (ppr (is_mod decl_spec)), source_import,
- ptext SLIT("does not export"), quotes (ppr ie)]
- where
- source_import | mi_boot iface = ptext SLIT("(hi-boot interface)")
- | 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)
-
-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
- 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),
- ptext SLIT("is exported by"), quotes (ppr ie1),
- ptext SLIT("and"), quotes (ppr ie2)]
-
-dupModuleExport mod
- = hsep [ptext SLIT("Duplicate"),
- quotes (ptext SLIT("Module") <+> ppr mod),
- ptext SLIT("in export list")]
-
-moduleDeprec mod txt
- = sep [ ptext SLIT("Module") <+> quotes (ppr mod) <+> ptext SLIT("is deprecated:"),
- nest 4 (ppr txt) ]
-\end{code}
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