2 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
4 \section[RnNames]{Extracting imported and top-level names in scope}
8 rnImports, mkRdrEnvAndImports, importsFromLocalDecls,
9 rnExports, mkExportNameSet,
10 getLocalDeclBinders, extendRdrEnvRn,
11 reportUnusedNames, reportDeprecations
14 #include "HsVersions.h"
16 import DynFlags ( DynFlag(..), GhcMode(..), DynFlags(..) )
17 import HsSyn ( IE(..), ieName, ImportDecl(..), LImportDecl,
18 ForeignDecl(..), HsGroup(..), HsValBinds(..),
19 Sig(..), collectHsBindLocatedBinders, tyClDeclNames,
20 instDeclATs, isIdxTyDecl,
23 import IfaceEnv ( ifaceExportNames )
24 import LoadIface ( loadSrcInterface )
25 import TcRnMonad hiding (LIE)
30 import Name ( Name, nameSrcLoc, nameOccName, nameModule, isWiredInName,
31 nameParent, nameParent_maybe, isExternalName,
35 import OccName ( srcDataName, isTcOcc, pprNonVarNameSpace,
37 OccEnv, mkOccEnv, lookupOccEnv, emptyOccEnv,
39 import HscTypes ( GenAvailInfo(..), AvailInfo,
40 HomePackageTable, PackageIfaceTable,
42 Deprecs(..), ModIface(..), Dependencies(..),
43 lookupIfaceByModule, ExternalPackageState(..)
45 import RdrName ( RdrName, rdrNameOcc, setRdrNameSpace,
46 GlobalRdrEnv, mkGlobalRdrEnv, GlobalRdrElt(..),
47 emptyGlobalRdrEnv, plusGlobalRdrEnv, globalRdrEnvElts,
48 extendGlobalRdrEnv, lookupGlobalRdrEnv, unQualOK, lookupGRE_Name,
49 Provenance(..), ImportSpec(..), ImpDeclSpec(..), ImpItemSpec(..),
50 importSpecLoc, importSpecModule, isLocalGRE, pprNameProvenance )
53 import Maybes ( isNothing, catMaybes, mapCatMaybes, seqMaybe, orElse )
54 import SrcLoc ( Located(..), mkGeneralSrcSpan,
55 unLoc, noLoc, srcLocSpan, SrcSpan )
56 import BasicTypes ( DeprecTxt )
57 import DriverPhases ( isHsBoot )
58 import Util ( notNull )
59 import List ( partition )
60 import IO ( openFile, IOMode(..) )
61 import Monad ( liftM )
66 %************************************************************************
70 %************************************************************************
73 rnImports :: [LImportDecl RdrName] -> RnM [LImportDecl Name]
75 -- PROCESS IMPORT DECLS
76 -- Do the non {- SOURCE -} ones first, so that we get a helpful
77 -- warning for {- SOURCE -} ones that are unnecessary
78 = do this_mod <- getModule
79 implicit_prelude <- doptM Opt_ImplicitPrelude
80 let all_imports = mk_prel_imports this_mod implicit_prelude ++ imports
81 (source, ordinary) = partition is_source_import all_imports
82 is_source_import (L _ (ImportDecl _ is_boot _ _ _)) = is_boot
83 get_imports = rnImportDecl this_mod
85 stuff1 <- mapM get_imports ordinary
86 stuff2 <- mapM get_imports source
87 return (stuff1 ++ stuff2)
89 -- NB: opt_NoImplicitPrelude is slightly different to import Prelude ();
90 -- because the former doesn't even look at Prelude.hi for instance
91 -- declarations, whereas the latter does.
92 mk_prel_imports this_mod implicit_prelude
94 || explicit_prelude_import
95 || not implicit_prelude
97 | otherwise = [preludeImportDecl]
98 explicit_prelude_import
99 = notNull [ () | L _ (ImportDecl mod _ _ _ _) <- imports,
100 unLoc mod == pRELUDE_NAME ]
102 preludeImportDecl :: LImportDecl RdrName
105 ImportDecl (L loc pRELUDE_NAME)
106 False {- Not a boot interface -}
107 False {- Not qualified -}
108 Nothing {- No "as" -}
109 Nothing {- No import list -}
111 loc = mkGeneralSrcSpan FSLIT("Implicit import declaration")
113 mkRdrEnvAndImports :: [LImportDecl Name] -> RnM (GlobalRdrEnv, ImportAvails)
114 mkRdrEnvAndImports imports
115 = do this_mod <- getModule
116 let get_imports = importsFromImportDecl this_mod
117 stuff <- mapM get_imports imports
118 let (imp_gbl_envs, imp_avails) = unzip stuff
119 gbl_env :: GlobalRdrEnv
120 gbl_env = foldr plusGlobalRdrEnv emptyGlobalRdrEnv imp_gbl_envs
122 all_avails :: ImportAvails
123 all_avails = foldr plusImportAvails emptyImportAvails imp_avails
125 return (gbl_env, all_avails)
130 rnImportDecl :: Module
131 -> LImportDecl RdrName
132 -> RnM (LImportDecl Name)
133 rnImportDecl this_mod (L loc importDecl@(ImportDecl loc_imp_mod_name want_boot qual_only as_mod imp_details))
135 do iface <- loadSrcInterface doc imp_mod_name want_boot
136 let qual_mod_name = case as_mod of
137 Nothing -> imp_mod_name
138 Just another_name -> another_name
139 imp_spec = ImpDeclSpec { is_mod = imp_mod_name, is_qual = qual_only,
140 is_dloc = loc, is_as = qual_mod_name }
141 total_avails <- ifaceExportNames (mi_exports iface)
142 importDecl' <- rnImportDecl' iface imp_spec importDecl total_avails
143 return (L loc importDecl')
144 where imp_mod_name = unLoc loc_imp_mod_name
145 doc = ppr imp_mod_name <+> ptext SLIT("is directly imported")
147 rnImportDecl' :: ModIface -> ImpDeclSpec -> ImportDecl RdrName -> NameSet -> RnM (ImportDecl Name)
148 rnImportDecl' iface decl_spec (ImportDecl mod_name want_boot qual_only as_mod Nothing) all_names
149 = return $ ImportDecl mod_name want_boot qual_only as_mod Nothing
150 rnImportDecl' iface decl_spec (ImportDecl mod_name want_boot qual_only as_mod (Just (want_hiding,import_items))) all_names
151 = do import_items_mbs <- mapM (srcSpanWrapper) import_items
152 let rn_import_items = concat . catMaybes $ import_items_mbs
153 return $ ImportDecl mod_name want_boot qual_only as_mod (Just (want_hiding,rn_import_items))
155 srcSpanWrapper (L span ieRdr)
156 = case get_item ieRdr of
158 -> do addErrAt span (badImportItemErr iface decl_spec ieRdr)
161 -> return (Just [L span ie | ie <- ieNames])
162 occ_env :: OccEnv Name -- Maps OccName to corresponding Name
163 occ_env = mkOccEnv [(nameOccName n, n) | n <- nameSetToList all_names]
164 -- This env will have entries for data constructors too,
165 -- they won't make any difference because naked entities like T
166 -- in an import list map to TcOccs, not VarOccs.
168 sub_env :: NameEnv [Name]
169 sub_env = mkSubNameEnv all_names
171 get_item :: IE RdrName -> Maybe [IE Name]
172 -- Empty result for a bad item.
173 -- Singleton result is typical case.
174 -- Can have two when we are hiding, and mention C which might be
175 -- both a class and a data constructor.
176 get_item item@(IEModuleContents _)
178 get_item (IEThingAll tc)
179 = do name <- check_name tc
180 return [IEThingAll name]
181 get_item (IEThingAbs tc)
182 | want_hiding -- hiding ( C )
183 -- Here the 'C' can be a data constructor
184 -- *or* a type/class, or even both
185 = case catMaybes [check_name tc, check_name (setRdrNameSpace tc srcDataName)] of
187 names -> return [ IEThingAbs n | n <- names ]
189 = do name <- check_name tc
190 return [IEThingAbs name]
191 get_item (IEThingWith n ns) -- import (C (A,B))
192 = do name <- check_name n
193 let env = mkOccEnv [(nameOccName s, s) | s <- subNames sub_env name]
194 mb_names = map (lookupOccEnv env . rdrNameOcc) ns
195 names <- sequence mb_names
196 return [IEThingWith name names]
198 = do name <- check_name n
201 check_name :: RdrName -> Maybe Name
203 = lookupOccEnv occ_env (rdrNameOcc rdrName)
206 importsFromImportDecl :: Module
208 -> RnM (GlobalRdrEnv, ImportAvails)
210 importsFromImportDecl this_mod
211 (L loc (ImportDecl loc_imp_mod_name want_boot qual_only as_mod imp_details))
215 -- If there's an error in loadInterface, (e.g. interface
216 -- file not found) we get lots of spurious errors from 'filterImports'
218 imp_mod_name = unLoc loc_imp_mod_name
219 doc = ppr imp_mod_name <+> ptext SLIT("is directly imported")
221 loadSrcInterface doc imp_mod_name want_boot `thenM` \ iface ->
223 -- Compiler sanity check: if the import didn't say
224 -- {-# SOURCE #-} we should not get a hi-boot file
225 WARN( not want_boot && mi_boot iface, ppr imp_mod_name )
227 -- Issue a user warning for a redundant {- SOURCE -} import
228 -- NB that we arrange to read all the ordinary imports before
229 -- any of the {- SOURCE -} imports
230 warnIf (want_boot && not (mi_boot iface))
231 (warnRedundantSourceImport imp_mod_name) `thenM_`
234 imp_mod = mi_module iface
235 deprecs = mi_deprecs iface
236 is_orph = mi_orphan iface
239 filtered_exports = filter not_this_mod (mi_exports iface)
240 not_this_mod (mod,_) = mod /= this_mod
241 -- If the module exports anything defined in this module, just ignore it.
242 -- Reason: otherwise it looks as if there are two local definition sites
243 -- for the thing, and an error gets reported. Easiest thing is just to
244 -- filter them out up front. This situation only arises if a module
245 -- imports itself, or another module that imported it. (Necessarily,
246 -- this invoves a loop.)
248 -- Tiresome consequence: if you say
253 -- module B( AType ) where
254 -- import {-# SOURCE #-} A( AType )
256 -- then you'll get a 'B does not export AType' message. Oh well.
258 qual_mod_name = case as_mod of
259 Nothing -> imp_mod_name
260 Just another_name -> another_name
261 imp_spec = ImpDeclSpec { is_mod = imp_mod_name, is_qual = qual_only,
262 is_dloc = loc, is_as = qual_mod_name }
264 -- Get the total imports, and filter them according to the import list
265 ifaceExportNames filtered_exports `thenM` \ total_avails ->
266 filterImports iface imp_spec
267 imp_details total_avails `thenM` \ (avail_env, gbl_env) ->
269 getDOpts `thenM` \ dflags ->
272 -- Compute new transitive dependencies
274 orphans | is_orph = ASSERT( not (imp_mod `elem` dep_orphs deps) )
275 imp_mod : dep_orphs deps
276 | otherwise = dep_orphs deps
278 pkg = modulePackageId (mi_module iface)
280 (dependent_mods, dependent_pkgs)
281 | pkg == thisPackage dflags =
282 -- Imported module is from the home package
283 -- Take its dependent modules and add imp_mod itself
284 -- Take its dependent packages unchanged
286 -- NB: (dep_mods deps) might include a hi-boot file
287 -- for the module being compiled, CM. Do *not* filter
288 -- this out (as we used to), because when we've
289 -- finished dealing with the direct imports we want to
290 -- know if any of them depended on CM.hi-boot, in
291 -- which case we should do the hi-boot consistency
292 -- check. See LoadIface.loadHiBootInterface
293 ((imp_mod_name, want_boot) : dep_mods deps, dep_pkgs deps)
296 -- Imported module is from another package
297 -- Dump the dependent modules
298 -- Add the package imp_mod comes from to the dependent packages
299 ASSERT2( not (pkg `elem` dep_pkgs deps), ppr pkg <+> ppr (dep_pkgs deps) )
300 ([], pkg : dep_pkgs deps)
302 -- True <=> import M ()
303 import_all = case imp_details of
304 Just (is_hiding, ls) -> not is_hiding && null ls
307 -- unqual_avails is the Avails that are visible in *unqualified* form
308 -- We need to know this so we know what to export when we see
309 -- module M ( module P ) where ...
310 -- Then we must export whatever came from P unqualified.
311 imports = ImportAvails {
312 imp_env = unitUFM qual_mod_name avail_env,
313 imp_mods = unitModuleEnv imp_mod (imp_mod, import_all, loc),
315 imp_dep_mods = mkModDeps dependent_mods,
316 imp_dep_pkgs = dependent_pkgs }
319 -- Complain if we import a deprecated module
320 ifOptM Opt_WarnDeprecations (
322 DeprecAll txt -> addWarn (moduleDeprec imp_mod_name txt)
326 returnM (gbl_env, imports)
328 warnRedundantSourceImport mod_name
329 = ptext SLIT("Unnecessary {-# SOURCE #-} in the import of module")
330 <+> quotes (ppr mod_name)
334 %************************************************************************
336 importsFromLocalDecls
338 %************************************************************************
340 From the top-level declarations of this module produce
341 * the lexical environment
343 created by its bindings.
345 Complain about duplicate bindings
348 importsFromLocalDecls :: HsGroup RdrName -> RnM TcGblEnv
349 importsFromLocalDecls group
350 = do { gbl_env <- getGblEnv
352 ; names <- getLocalDeclBinders gbl_env group
354 ; implicit_prelude <- doptM Opt_ImplicitPrelude
356 -- Optimisation: filter out names for built-in syntax
357 -- They just clutter up the environment (esp tuples), and the parser
358 -- will generate Exact RdrNames for them, so the cluttered
359 -- envt is no use. To avoid doing this filter all the time,
360 -- we use -fno-implicit-prelude as a clue that the filter is
361 -- worth while. Really, it's only useful for GHC.Base and GHC.Tuple.
363 -- It's worth doing because it makes the environment smaller for
364 -- every module that imports the Prelude
366 -- Note: don't filter the gbl_env (hence all_names, not filered_all_names
367 -- in defn of gres above). Stupid reason: when parsing
368 -- data type decls, the constructors start as Exact tycon-names,
369 -- and then get turned into data con names by zapping the name space;
370 -- but that stops them being Exact, so they get looked up.
371 -- Ditto in fixity decls; e.g. infix 5 :
372 -- Sigh. It doesn't matter because it only affects the Data.Tuple really.
373 -- The important thing is to trim down the exports.
375 | implicit_prelude = names
376 | otherwise = filter (not . isBuiltInSyntax) names ;
378 ; this_mod = tcg_mod gbl_env
379 ; imports = emptyImportAvails {
380 imp_env = unitUFM (moduleName this_mod) $
381 mkNameSet filtered_names
385 ; rdr_env' <- extendRdrEnvRn (tcg_rdr_env gbl_env) names
387 ; returnM (gbl_env { tcg_rdr_env = rdr_env',
388 tcg_imports = imports `plusImportAvails` tcg_imports gbl_env })
391 extendRdrEnvRn :: GlobalRdrEnv -> [Name] -> RnM GlobalRdrEnv
392 -- Add the new locally-bound names one by one, checking for duplicates as
393 -- we do so. Remember that in Template Haskell the duplicates
394 -- might *already be* in the GlobalRdrEnv from higher up the module
395 extendRdrEnvRn rdr_env names
396 = foldlM add_local rdr_env names
398 add_local rdr_env name
399 | gres <- lookupGlobalRdrEnv rdr_env (nameOccName name)
400 , (dup_gre:_) <- filter isLocalGRE gres -- Check for existing *local* defns
401 = do { addDupDeclErr (gre_name dup_gre) name
404 = return (extendGlobalRdrEnv rdr_env new_gre)
406 new_gre = GRE {gre_name = name, gre_prov = LocalDef}
409 @getLocalDeclBinders@ returns the names for an @HsDecl@. It's
410 used for source code.
412 *** See "THE NAMING STORY" in HsDecls ****
414 Instances of indexed types
415 ~~~~~~~~~~~~~~~~~~~~~~~~~~
416 Indexed data/newtype instances contain data constructors that we need to
417 collect, too. Moreover, we need to descend into the data/newtypes instances
418 of associated families.
420 We need to be careful with the handling of the type constructor of each type
421 instance as the family constructor is already defined, and we want to avoid
422 raising a duplicate declaration error. So, we make a new name for it, but
423 don't return it in the 'AvailInfo'.
426 getLocalDeclBinders :: TcGblEnv -> HsGroup RdrName -> RnM [Name]
427 getLocalDeclBinders gbl_env (HsGroup {hs_valds = ValBindsIn val_decls val_sigs,
428 hs_tyclds = tycl_decls,
429 hs_instds = inst_decls,
430 hs_fords = foreign_decls })
431 = do { tc_names_s <- mappM new_tc tycl_decls
432 ; at_names_s <- mappM inst_ats inst_decls
433 ; val_names <- mappM new_simple val_bndrs
434 ; return (foldr (++) val_names (tc_names_s ++ concat at_names_s)) }
436 mod = tcg_mod gbl_env
437 is_hs_boot = isHsBoot (tcg_src gbl_env) ;
438 val_bndrs | is_hs_boot = sig_hs_bndrs
439 | otherwise = for_hs_bndrs ++ val_hs_bndrs
440 -- In a hs-boot file, the value binders come from the
441 -- *signatures*, and there should be no foreign binders
443 new_simple rdr_name = newTopSrcBinder mod Nothing rdr_name
445 sig_hs_bndrs = [nm | L _ (TypeSig nm _) <- val_sigs]
446 val_hs_bndrs = collectHsBindLocatedBinders val_decls
447 for_hs_bndrs = [nm | L _ (ForeignImport nm _ _) <- foreign_decls]
450 = do { main_name <- newTopSrcBinder mod Nothing main_rdr
451 ; sub_names <- mappM (newTopSrcBinder mod (Just main_name)) sub_rdrs
452 ; if isIdxTyDecl (unLoc tc_decl) -- index type definitions
453 then return ( sub_names) -- are usage occurences
454 else return (main_name : sub_names) }
456 (main_rdr : sub_rdrs) = tyClDeclNames (unLoc tc_decl)
459 = mappM new_tc (instDeclATs (unLoc inst_decl))
463 %************************************************************************
465 \subsection{Filtering imports}
467 %************************************************************************
469 @filterImports@ takes the @ExportEnv@ telling what the imported module makes
470 available, and filters it through the import spec (if any).
473 filterImports :: ModIface
474 -> ImpDeclSpec -- The span for the entire import decl
475 -> Maybe (Bool, [LIE Name]) -- Import spec; True => hiding
476 -> NameSet -- What's available
477 -> RnM (NameSet, -- What's imported (qualified or unqualified)
478 GlobalRdrEnv) -- Same again, but in GRE form
480 -- Complains if import spec mentions things that the module doesn't export
481 -- Warns/informs if import spec contains duplicates.
483 mkGenericRdrEnv decl_spec names
484 = mkGlobalRdrEnv [ GRE { gre_name = name, gre_prov = Imported [imp_spec] }
485 | name <- nameSetToList names ]
487 imp_spec = ImpSpec { is_decl = decl_spec, is_item = ImpAll }
489 filterImports iface decl_spec Nothing all_names
490 = return (all_names, mkGenericRdrEnv decl_spec all_names)
492 filterImports iface decl_spec (Just (want_hiding, import_items)) all_names
493 = mapM (addLocM get_item) import_items >>= \gres_s ->
494 let gres = concat gres_s
495 specified_names = mkNameSet (map gre_name gres)
496 in if not want_hiding then
497 return (specified_names, mkGlobalRdrEnv gres)
498 else let keep n = not (n `elemNameSet` specified_names)
499 pruned_avails = filterNameSet keep all_names
500 in return (pruned_avails, mkGenericRdrEnv decl_spec pruned_avails)
502 sub_env :: NameEnv [Name] -- Classify each name by its parent
503 sub_env = mkSubNameEnv all_names
505 succeed_with :: Bool -> [Name] -> RnM [GlobalRdrElt]
506 succeed_with all_explicit names
507 = do { loc <- getSrcSpanM
508 ; returnM (map (mk_gre loc) names) }
510 mk_gre loc name = GRE { gre_name = name,
511 gre_prov = Imported [imp_spec] }
513 imp_spec = ImpSpec { is_decl = decl_spec, is_item = item_spec }
514 item_spec = ImpSome { is_explicit = explicit, is_iloc = loc }
515 explicit = all_explicit || isNothing (nameParent_maybe name)
517 get_item :: IE Name -> RnM [GlobalRdrElt]
518 -- Empty result for a bad item.
519 -- Singleton result is typical case.
520 -- Can have two when we are hiding, and mention C which might be
521 -- both a class and a data constructor.
522 get_item item@(IEModuleContents _)
523 -- This case should be filtered out by 'rnImports'.
524 = panic "filterImports: IEModuleContents?"
526 get_item (IEThingAll name)
527 = case subNames sub_env name of
528 [] -> -- This occurs when you import T(..), but
529 -- only export T abstractly.
530 do ifOptM Opt_WarnDodgyImports (addWarn (dodgyImportWarn name))
531 succeed_with False [name]
532 names -> succeed_with False (name:names)
534 get_item (IEThingAbs name)
535 = succeed_with True [name]
537 get_item (IEThingWith name names)
538 = succeed_with True (name:names)
539 get_item (IEVar name)
540 = succeed_with True [name]
545 %************************************************************************
547 \subsection{Export list processing}
549 %************************************************************************
551 Processing the export list.
553 You might think that we should record things that appear in the export
554 list as ``occurrences'' (using @addOccurrenceName@), but you'd be
555 wrong. We do check (here) that they are in scope, but there is no
556 need to slurp in their actual declaration (which is what
557 @addOccurrenceName@ forces).
559 Indeed, doing so would big trouble when compiling @PrelBase@, because
560 it re-exports @GHC@, which includes @takeMVar#@, whose type includes
561 @ConcBase.StateAndSynchVar#@, and so on...
564 type ExportAccum -- The type of the accumulating parameter of
565 -- the main worker function in rnExports
566 = ([ModuleName], -- 'module M's seen so far
567 ExportOccMap, -- Tracks exported occurrence names
568 NameSet) -- The accumulated exported stuff
569 emptyExportAccum = ([], emptyOccEnv, emptyNameSet)
571 type ExportOccMap = OccEnv (Name, IE RdrName)
572 -- Tracks what a particular exported OccName
573 -- in an export list refers to, and which item
574 -- it came from. It's illegal to export two distinct things
575 -- that have the same occurrence name
577 rnExports :: Maybe [LIE RdrName]
578 -> RnM (Maybe [LIE Name])
579 rnExports Nothing = return Nothing
580 rnExports (Just exports)
581 = do TcGblEnv { tcg_imports = ImportAvails { imp_env = imp_env } } <- getGblEnv
582 let sub_env :: NameEnv [Name] -- Classify each name by its parent
583 sub_env = mkSubNameEnv (foldUFM unionNameSets emptyNameSet imp_env)
584 rnExport (IEVar rdrName)
585 = do name <- lookupGlobalOccRn rdrName
587 rnExport (IEThingAbs rdrName)
588 = do name <- lookupGlobalOccRn rdrName
589 return (IEThingAbs name)
590 rnExport (IEThingAll rdrName)
591 = do name <- lookupGlobalOccRn rdrName
592 return (IEThingAll name)
593 rnExport ie@(IEThingWith rdrName rdrNames)
594 = do name <- lookupGlobalOccRn rdrName
595 if isUnboundName name
596 then return (IEThingWith name [])
598 let env = mkOccEnv [(nameOccName s, s) | s <- subNames sub_env name]
599 mb_names = map (lookupOccEnv env . rdrNameOcc) rdrNames
600 if any isNothing mb_names
601 then do addErr (exportItemErr ie)
602 return (IEThingWith name [])
603 else return (IEThingWith name (catMaybes mb_names))
604 rnExport (IEModuleContents mod)
605 = return (IEModuleContents mod)
606 rn_exports <- mapM (wrapLocM rnExport) exports
607 return (Just rn_exports)
609 mkExportNameSet :: Bool -- False => no 'module M(..) where' header at all
610 -> Maybe ([LIE Name], [LIE RdrName]) -- Nothing => no explicit export list
612 -- Complains if two distinct exports have same OccName
613 -- Warns about identical exports.
614 -- Complains about exports items not in scope
616 mkExportNameSet explicit_mod exports
617 = do TcGblEnv { tcg_rdr_env = rdr_env,
618 tcg_imports = imports } <- getGblEnv
620 -- If the module header is omitted altogether, then behave
621 -- as if the user had written "module Main(main) where..."
622 -- EXCEPT in interactive mode, when we behave as if he had
623 -- written "module Main where ..."
624 -- Reason: don't want to complain about 'main' not in scope
625 -- in interactive mode
626 ghc_mode <- getGhcMode
627 real_exports <- case () of
630 | ghc_mode == Interactive
633 -> do mainName <- lookupGlobalOccRn main_RDR_Unqual
634 return (Just ([noLoc (IEVar mainName)]
635 ,[noLoc (IEVar main_RDR_Unqual)]))
636 -- ToDo: the 'noLoc' here is unhelpful if 'main' turns out to be out of scope
637 exports_from_avail real_exports rdr_env imports
640 exports_from_avail Nothing rdr_env imports
641 = -- Export all locally-defined things
642 -- We do this by filtering the global RdrEnv,
643 -- keeping only things that are locally-defined
644 return (mkNameSet [ gre_name gre
645 | gre <- globalRdrEnvElts rdr_env,
648 exports_from_avail (Just (items,origItems)) rdr_env (ImportAvails { imp_env = imp_env })
649 = do (_, _, exports) <- foldlM do_litem emptyExportAccum (zip items origItems)
652 sub_env :: NameEnv [Name] -- Classify each name by its parent
653 sub_env = mkSubNameEnv (foldUFM unionNameSets emptyNameSet imp_env)
655 do_litem :: ExportAccum -> (LIE Name, LIE RdrName) -> RnM ExportAccum
656 do_litem acc (ieName, ieRdr)
657 = addLocM (exports_from_item acc (unLoc ieRdr)) ieName
659 exports_from_item :: ExportAccum -> IE RdrName -> IE Name -> RnM ExportAccum
660 exports_from_item acc@(mods, occs, exports) ieRdr@(IEModuleContents mod) ie
661 | mod `elem` mods -- Duplicate export of M
662 = do { warn_dup_exports <- doptM Opt_WarnDuplicateExports ;
663 warnIf warn_dup_exports (dupModuleExport mod) ;
667 = case lookupUFM imp_env mod of
668 Nothing -> do addErr (modExportErr mod)
671 -> do let new_exports = filterNameSet (inScopeUnqual rdr_env) names
672 -- This check_occs not only finds conflicts between this item
673 -- and others, but also internally within this item. That is,
674 -- if 'M.x' is in scope in several ways, we'll have several
675 -- members of mod_avails with the same OccName.
676 occs' <- check_occs ieRdr occs (nameSetToList new_exports)
677 return (mod:mods, occs', exports `unionNameSets` new_exports)
679 exports_from_item acc@(mods, occs, exports) ieRdr ie
680 = if isUnboundName (ieName ie)
681 then return acc -- Avoid error cascade
682 else let new_exports = filterAvail ie sub_env in
683 do -- checkErr (not (null (drop 1 new_exports))) (exportItemErr ie)
684 checkForDodgyExport ie new_exports
685 occs' <- check_occs ieRdr occs new_exports
686 return (mods, occs', addListToNameSet exports new_exports)
688 -------------------------------
689 filterAvail :: IE Name -- Wanted
690 -> NameEnv [Name] -- Maps type/class names to their sub-names
693 filterAvail (IEVar n) subs = [n]
694 filterAvail (IEThingAbs n) subs = [n]
695 filterAvail (IEThingAll n) subs = n : subNames subs n
696 filterAvail (IEThingWith n ns) subs = n : ns
697 filterAvail (IEModuleContents _) _ = panic "filterAvail"
699 subNames :: NameEnv [Name] -> Name -> [Name]
700 subNames env n = lookupNameEnv env n `orElse` []
702 mkSubNameEnv :: NameSet -> NameEnv [Name]
703 -- Maps types and classes to their constructors/classops respectively
704 -- This mapping just makes it easier to deal with A(..) export items
706 = foldNameSet add_name emptyNameEnv names
709 | Just parent <- nameParent_maybe name
710 = extendNameEnv_C (\ns _ -> name:ns) env parent [name]
713 -------------------------------
714 inScopeUnqual :: GlobalRdrEnv -> Name -> Bool
715 -- Checks whether the Name is in scope unqualified,
716 -- regardless of whether it's ambiguous or not
717 inScopeUnqual env n = any unQualOK (lookupGRE_Name env n)
719 -------------------------------
720 checkForDodgyExport :: IE Name -> [Name] -> RnM ()
721 checkForDodgyExport ie@(IEThingAll tc) [n]
722 | isTcOcc (nameOccName n) = addWarn (dodgyExportWarn tc)
723 -- This occurs when you export T(..), but
724 -- only import T abstractly, or T is a synonym.
725 -- The single [n] is the type or class itself
726 | otherwise = addErr (exportItemErr ie)
727 -- This happes if you export x(..), which is bogus
728 checkForDodgyExport _ _ = return ()
730 -------------------------------
731 check_occs :: IE RdrName -> ExportOccMap -> [Name] -> RnM ExportOccMap
732 check_occs ie occs names
733 = foldlM check occs names
736 = case lookupOccEnv occs name_occ of
737 Nothing -> returnM (extendOccEnv occs name_occ (name, ie))
740 | name == name' -- Duplicate export
741 -> do { warn_dup_exports <- doptM Opt_WarnDuplicateExports ;
742 warnIf warn_dup_exports (dupExportWarn name_occ ie ie') ;
745 | otherwise -- Same occ name but different names: an error
746 -> do { global_env <- getGlobalRdrEnv ;
747 addErr (exportClashErr global_env name' name ie' ie) ;
750 name_occ = nameOccName name
753 %*********************************************************
757 %*********************************************************
760 reportDeprecations :: DynFlags -> TcGblEnv -> RnM ()
761 reportDeprecations dflags tcg_env
762 = ifOptM Opt_WarnDeprecations $
763 do { (eps,hpt) <- getEpsAndHpt
764 -- By this time, typechecking is complete,
765 -- so the PIT is fully populated
766 ; mapM_ (check hpt (eps_PIT eps)) all_gres }
768 used_names = allUses (tcg_dus tcg_env)
769 -- Report on all deprecated uses; hence allUses
770 all_gres = globalRdrEnvElts (tcg_rdr_env tcg_env)
772 check hpt pit (GRE {gre_name = name, gre_prov = Imported (imp_spec:_)})
773 | name `elemNameSet` used_names
774 , Just deprec_txt <- lookupDeprec dflags hpt pit name
775 = addWarnAt (importSpecLoc imp_spec)
776 (sep [ptext SLIT("Deprecated use of") <+>
777 pprNonVarNameSpace (occNameSpace (nameOccName name)) <+>
779 (parens imp_msg) <> colon,
782 name_mod = nameModule name
783 imp_mod = importSpecModule imp_spec
784 imp_msg = ptext SLIT("imported from") <+> ppr imp_mod <> extra
785 extra | imp_mod == moduleName name_mod = empty
786 | otherwise = ptext SLIT(", but defined in") <+> ppr name_mod
788 check hpt pit ok_gre = returnM () -- Local, or not used, or not deprectated
789 -- The Imported pattern-match: don't deprecate locally defined names
790 -- For a start, we may be exporting a deprecated thing
791 -- Also we may use a deprecated thing in the defn of another
792 -- deprecated things. We may even use a deprecated thing in
793 -- the defn of a non-deprecated thing, when changing a module's
796 lookupDeprec :: DynFlags -> HomePackageTable -> PackageIfaceTable
797 -> Name -> Maybe DeprecTxt
798 lookupDeprec dflags hpt pit n
799 = case lookupIfaceByModule dflags hpt pit (nameModule n) of
800 Just iface -> mi_dep_fn iface n `seqMaybe` -- Bleat if the thing, *or
801 mi_dep_fn iface (nameParent n) -- its parent*, is deprec'd
803 | isWiredInName n -> Nothing
804 -- We have not necessarily loaded the .hi file for a
805 -- wired-in name (yet), although we *could*.
806 -- And we never deprecate them
808 | otherwise -> pprPanic "lookupDeprec" (ppr n)
809 -- By now all the interfaces should have been loaded
811 gre_is_used :: NameSet -> GlobalRdrElt -> Bool
812 gre_is_used used_names gre = gre_name gre `elemNameSet` used_names
815 %*********************************************************
819 %*********************************************************
822 reportUnusedNames :: Maybe [LIE RdrName] -- Export list
823 -> TcGblEnv -> RnM ()
824 reportUnusedNames export_decls gbl_env
825 = do { traceRn ((text "RUN") <+> (ppr (tcg_dus gbl_env)))
826 ; warnUnusedTopBinds unused_locals
827 ; warnUnusedModules unused_imp_mods
828 ; warnUnusedImports unused_imports
829 ; warnDuplicateImports defined_and_used
830 ; printMinimalImports minimal_imports }
832 used_names, all_used_names :: NameSet
833 used_names = findUses (tcg_dus gbl_env) emptyNameSet
834 -- NB: currently, if f x = g, we only treat 'g' as used if 'f' is used
837 all_used_names = used_names `unionNameSets`
838 mkNameSet (mapCatMaybes nameParent_maybe (nameSetToList used_names))
839 -- A use of C implies a use of T,
840 -- if C was brought into scope by T(..) or T(C)
842 -- Collect the defined names from the in-scope environment
843 defined_names :: [GlobalRdrElt]
844 defined_names = globalRdrEnvElts (tcg_rdr_env gbl_env)
846 -- Note that defined_and_used, defined_but_not_used
847 -- are both [GRE]; that's why we need defined_and_used
848 -- rather than just all_used_names
849 defined_and_used, defined_but_not_used :: [GlobalRdrElt]
850 (defined_and_used, defined_but_not_used)
851 = partition (gre_is_used all_used_names) defined_names
853 -- Filter out the ones that are
854 -- (a) defined in this module, and
855 -- (b) not defined by a 'deriving' clause
856 -- The latter have an Internal Name, so we can filter them out easily
857 unused_locals :: [GlobalRdrElt]
858 unused_locals = filter is_unused_local defined_but_not_used
859 is_unused_local :: GlobalRdrElt -> Bool
860 is_unused_local gre = isLocalGRE gre && isExternalName (gre_name gre)
862 unused_imports :: [GlobalRdrElt]
863 unused_imports = filter unused_imp defined_but_not_used
864 unused_imp (GRE {gre_prov = Imported imp_specs})
865 = not (all (module_unused . importSpecModule) imp_specs)
866 && or [exp | ImpSpec { is_item = ImpSome { is_explicit = exp } } <- imp_specs]
867 -- Don't complain about unused imports if we've already said the
868 -- entire import is unused
869 unused_imp other = False
871 -- To figure out the minimal set of imports, start with the things
872 -- that are in scope (i.e. in gbl_env). Then just combine them
873 -- into a bunch of avails, so they are properly grouped
875 -- BUG WARNING: this does not deal properly with qualified imports!
876 minimal_imports :: FiniteMap ModuleName AvailEnv
877 minimal_imports0 = foldr add_expall emptyFM expall_mods
878 minimal_imports1 = foldr add_name minimal_imports0 defined_and_used
879 minimal_imports = foldr add_inst_mod minimal_imports1 direct_import_mods
880 -- The last line makes sure that we retain all direct imports
881 -- even if we import nothing explicitly.
882 -- It's not necessarily redundant to import such modules. Consider
886 -- The import M() is not *necessarily* redundant, even if
887 -- we suck in no instance decls from M (e.g. it contains
888 -- no instance decls, or This contains no code). It may be
889 -- that we import M solely to ensure that M's orphan instance
890 -- decls (or those in its imports) are visible to people who
891 -- import This. Sigh.
892 -- There's really no good way to detect this, so the error message
893 -- in RnEnv.warnUnusedModules is weakened instead
895 -- We've carefully preserved the provenance so that we can
896 -- construct minimal imports that import the name by (one of)
897 -- the same route(s) as the programmer originally did.
898 add_name (GRE {gre_name = n, gre_prov = Imported imp_specs}) acc
899 = addToFM_C plusAvailEnv acc (importSpecModule (head imp_specs))
900 (unitAvailEnv (mk_avail n (nameParent_maybe n)))
904 -- Modules mentioned as 'module M' in the export list
905 expall_mods = case export_decls of
907 Just es -> [m | L _ (IEModuleContents m) <- es]
909 -- This is really bogus. The idea is that if we see 'module M' in
910 -- the export list we must retain the import decls that drive it
911 -- If we aren't careful we might see
912 -- module A( module M ) where
915 -- and suppose that N exports everything that M does. Then we
916 -- must not drop the import of M even though N brings it all into
919 -- BUG WARNING: 'module M' exports aside, what if M.x is mentioned?!
921 -- The reason that add_expall is bogus is that it doesn't take
922 -- qualified imports into account. But it's an improvement.
923 add_expall mod acc = addToFM_C plusAvailEnv acc mod emptyAvailEnv
925 -- n is the name of the thing, p is the name of its parent
926 mk_avail n (Just p) = AvailTC p [p,n]
927 mk_avail n Nothing | isTcOcc (nameOccName n) = AvailTC n [n]
928 | otherwise = Avail n
930 add_inst_mod (mod,_,_) acc
931 | mod_name `elemFM` acc = acc -- We import something already
932 | otherwise = addToFM acc mod_name emptyAvailEnv
934 mod_name = moduleName mod
935 -- Add an empty collection of imports for a module
936 -- from which we have sucked only instance decls
938 imports = tcg_imports gbl_env
940 direct_import_mods :: [(Module, Bool, SrcSpan)]
941 -- See the type of the imp_mods for this triple
942 direct_import_mods = moduleEnvElts (imp_mods imports)
944 -- unused_imp_mods are the directly-imported modules
945 -- that are not mentioned in minimal_imports1
946 -- [Note: not 'minimal_imports', because that includes directly-imported
947 -- modules even if we use nothing from them; see notes above]
949 -- BUG WARNING: does not deal correctly with multiple imports of the same module
950 -- becuase direct_import_mods has only one entry per module
951 unused_imp_mods = [(mod_name,loc) | (mod,no_imp,loc) <- direct_import_mods,
952 let mod_name = moduleName mod,
953 not (mod_name `elemFM` minimal_imports1),
956 -- The not no_imp part is not to complain about
957 -- import M (), which is an idiom for importing
958 -- instance declarations
960 module_unused :: ModuleName -> Bool
961 module_unused mod = any (((==) mod) . fst) unused_imp_mods
963 ---------------------
964 warnDuplicateImports :: [GlobalRdrElt] -> RnM ()
965 -- Given the GREs for names that are used, figure out which imports
966 -- could be omitted without changing the top-level environment.
968 -- NB: Given import Foo( T )
969 -- import qualified Foo
970 -- we do not report a duplicate import, even though Foo.T is brought
971 -- into scope by both, because there's nothing you can *omit* without
972 -- changing the top-level environment. So we complain only if it's
973 -- explicitly named in both imports or neither.
975 -- Furthermore, we complain about Foo.T only if
976 -- there is no complaint about (unqualified) T
978 warnDuplicateImports gres
979 = ifOptM Opt_WarnUnusedImports $
980 sequenceM_ [ warn name pr
981 -- The 'head' picks the first offending group
982 -- for this particular name
983 | GRE { gre_name = name, gre_prov = Imported imps } <- gres
984 , pr <- redundants imps ]
986 warn name (red_imp, cov_imp)
987 = addWarnAt (importSpecLoc red_imp)
988 (vcat [ptext SLIT("Redundant import of:") <+> quotes pp_name,
989 ptext SLIT("It is also") <+> ppr cov_imp])
991 pp_name | is_qual red_decl = ppr (is_as red_decl) <> dot <> ppr occ
992 | otherwise = ppr occ
993 occ = nameOccName name
994 red_decl = is_decl red_imp
996 redundants :: [ImportSpec] -> [(ImportSpec,ImportSpec)]
997 -- The returned pair is (redundant-import, covering-import)
999 = [ (red_imp, cov_imp)
1001 , cov_imp <- take 1 (filter (covers red_imp) imps) ]
1003 -- "red_imp" is a putative redundant import
1004 -- "cov_imp" potentially covers it
1005 -- This test decides whether red_imp could be dropped
1007 -- NOTE: currently the test does not warn about
1010 -- even if the same underlying 'x' is involved, because dropping
1011 -- either import would change the qualified names in scope (M.x, N.x)
1012 -- But if the qualified names aren't used, the import is indeed redundant
1013 -- Sadly we don't know that. Oh well.
1014 covers red_imp@(ImpSpec { is_decl = red_decl, is_item = red_item })
1015 cov_imp@(ImpSpec { is_decl = cov_decl, is_item = cov_item })
1016 | red_loc == cov_loc
1017 = False -- Ignore diagonal elements
1018 | not (is_as red_decl == is_as cov_decl)
1019 = False -- They bring into scope different qualified names
1020 | not (is_qual red_decl) && is_qual cov_decl
1021 = False -- Covering one doesn't bring unqualified name into scope
1023 = not cov_selective -- Redundant one is selective and covering one isn't
1024 || red_later -- Both are explicit; tie-break using red_later
1026 = not cov_selective -- Neither import is selective
1027 && (is_mod red_decl == is_mod cov_decl) -- They import the same module
1028 && red_later -- Tie-break
1030 red_loc = importSpecLoc red_imp
1031 cov_loc = importSpecLoc cov_imp
1032 red_later = red_loc > cov_loc
1033 cov_selective = selectiveImpItem cov_item
1034 red_selective = selectiveImpItem red_item
1036 selectiveImpItem :: ImpItemSpec -> Bool
1037 selectiveImpItem ImpAll = False
1038 selectiveImpItem (ImpSome {}) = True
1040 -- ToDo: deal with original imports with 'qualified' and 'as M' clauses
1041 printMinimalImports :: FiniteMap ModuleName AvailEnv -- Minimal imports
1043 printMinimalImports imps
1044 = ifOptM Opt_D_dump_minimal_imports $ do {
1046 mod_ies <- mappM to_ies (fmToList imps) ;
1047 this_mod <- getModule ;
1048 rdr_env <- getGlobalRdrEnv ;
1049 ioToTcRn (do { h <- openFile (mkFilename this_mod) WriteMode ;
1050 printForUser h (mkPrintUnqualified rdr_env)
1051 (vcat (map ppr_mod_ie mod_ies)) })
1054 mkFilename this_mod = moduleNameString (moduleName this_mod) ++ ".imports"
1055 ppr_mod_ie (mod_name, ies)
1056 | mod_name == moduleName pRELUDE
1058 | null ies -- Nothing except instances comes from here
1059 = ptext SLIT("import") <+> ppr mod_name <> ptext SLIT("() -- Instances only")
1061 = ptext SLIT("import") <+> ppr mod_name <>
1062 parens (fsep (punctuate comma (map ppr ies)))
1064 to_ies (mod, avail_env) = do ies <- mapM to_ie (availEnvElts avail_env)
1067 to_ie :: AvailInfo -> RnM (IE Name)
1068 -- The main trick here is that if we're importing all the constructors
1069 -- we want to say "T(..)", but if we're importing only a subset we want
1070 -- to say "T(A,B,C)". So we have to find out what the module exports.
1071 to_ie (Avail n) = returnM (IEVar n)
1072 to_ie (AvailTC n [m]) = ASSERT( n==m )
1073 returnM (IEThingAbs n)
1074 to_ie (AvailTC n ns)
1075 = loadSrcInterface doc n_mod False `thenM` \ iface ->
1076 case [xs | (m,as) <- mi_exports iface,
1077 moduleName m == n_mod,
1079 x == nameOccName n] of
1080 [xs] | all_used xs -> returnM (IEThingAll n)
1081 | otherwise -> returnM (IEThingWith n (filter (/= n) ns))
1082 other -> pprTrace "to_ie" (ppr n <+> ppr n_mod <+> ppr other) $
1085 all_used avail_occs = all (`elem` map nameOccName ns) avail_occs
1086 doc = text "Compute minimal imports from" <+> ppr n
1087 n_mod = moduleName (nameModule n)
1091 %************************************************************************
1095 %************************************************************************
1098 badImportItemErr iface decl_spec ie
1099 = sep [ptext SLIT("Module"), quotes (ppr (is_mod decl_spec)), source_import,
1100 ptext SLIT("does not export"), quotes (ppr ie)]
1102 source_import | mi_boot iface = ptext SLIT("(hi-boot interface)")
1105 dodgyImportWarn item = dodgyMsg (ptext SLIT("import")) item
1106 dodgyExportWarn item = dodgyMsg (ptext SLIT("export")) item
1109 = sep [ ptext SLIT("The") <+> kind <+> ptext SLIT("item") <+> quotes (ppr (IEThingAll tc)),
1110 ptext SLIT("suggests that") <+> quotes (ppr tc) <+> ptext SLIT("has constructor or class methods"),
1111 ptext SLIT("but it has none; it is a type synonym or abstract type or class") ]
1114 = hsep [ ptext SLIT("Unknown module in export list: module"), quotes (ppr mod)]
1116 exportItemErr export_item
1117 = sep [ ptext SLIT("The export item") <+> quotes (ppr export_item),
1118 ptext SLIT("attempts to export constructors or class methods that are not visible here") ]
1120 exportClashErr global_env name1 name2 ie1 ie2
1121 = vcat [ ptext SLIT("Conflicting exports for") <+> quotes (ppr occ) <> colon
1122 , ppr_export ie1 name1
1123 , ppr_export ie2 name2 ]
1125 occ = nameOccName name1
1126 ppr_export ie name = nest 2 (quotes (ppr ie) <+> ptext SLIT("exports") <+>
1127 quotes (ppr name) <+> pprNameProvenance (get_gre name))
1129 -- get_gre finds a GRE for the Name, so that we can show its provenance
1131 = case lookupGRE_Name global_env name of
1133 [] -> pprPanic "exportClashErr" (ppr name)
1135 addDupDeclErr :: Name -> Name -> TcRn ()
1136 addDupDeclErr name_a name_b
1137 = addErrAt (srcLocSpan loc2) $
1138 vcat [ptext SLIT("Multiple declarations of") <+> quotes (ppr name1),
1139 ptext SLIT("Declared at:") <+> vcat [ppr (nameSrcLoc name1), ppr loc2]]
1141 loc2 = nameSrcLoc name2
1142 (name1,name2) | nameSrcLoc name_a > nameSrcLoc name_b = (name_b,name_a)
1143 | otherwise = (name_a,name_b)
1144 -- Report the error at the later location
1146 dupExportWarn occ_name ie1 ie2
1147 = hsep [quotes (ppr occ_name),
1148 ptext SLIT("is exported by"), quotes (ppr ie1),
1149 ptext SLIT("and"), quotes (ppr ie2)]
1152 = hsep [ptext SLIT("Duplicate"),
1153 quotes (ptext SLIT("Module") <+> ppr mod),
1154 ptext SLIT("in export list")]
1156 moduleDeprec mod txt
1157 = sep [ ptext SLIT("Module") <+> quotes (ppr mod) <+> ptext SLIT("is deprecated:"),