2 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
4 \section[RnNames]{Extracting imported and top-level names in scope}
8 rnImports, importsFromLocalDecls, exportsFromAvail,
9 reportUnusedNames, reportDeprecations,
10 mkModDeps, exportsToAvails
13 #include "HsVersions.h"
15 import CmdLineOpts ( DynFlag(..) )
16 import HsSyn ( IE(..), ieName, ImportDecl(..), LImportDecl,
17 ForeignDecl(..), HsGroup(..),
18 collectGroupBinders, tyClDeclNames
21 import IfaceEnv ( lookupOrig, newGlobalBinder )
22 import LoadIface ( loadSrcInterface )
26 import PrelNames ( pRELUDE_Name, isUnboundName,
28 import Module ( Module, ModuleName, moduleName, mkPackageModule,
29 moduleNameUserString, isHomeModule,
30 unitModuleEnvByName, unitModuleEnv,
31 lookupModuleEnvByName, moduleEnvElts )
32 import Name ( Name, nameSrcLoc, nameOccName, nameModuleName, isWiredInName,
33 nameParent, nameParent_maybe, isExternalName, nameModule,
36 import OccName ( srcDataName, isTcOcc, occNameFlavour, OccEnv,
37 mkOccEnv, lookupOccEnv, emptyOccEnv, extendOccEnv )
38 import HscTypes ( GenAvailInfo(..), AvailInfo, Avails, GhciMode(..),
39 IfaceExport, HomePackageTable, PackageIfaceTable,
40 availName, availNames, availsToNameSet, unQualInScope,
41 Deprecs(..), ModIface(..), Dependencies(..), lookupIface,
42 ExternalPackageState(..)
44 import RdrName ( RdrName, rdrNameOcc, setRdrNameSpace,
45 GlobalRdrEnv, mkGlobalRdrEnv, GlobalRdrElt(..),
46 emptyGlobalRdrEnv, plusGlobalRdrEnv, globalRdrEnvElts,
47 unQualOK, lookupGRE_Name,
48 Provenance(..), ImportSpec(..),
49 isLocalGRE, pprNameProvenance )
51 import Maybes ( isNothing, catMaybes, mapCatMaybes, seqMaybe )
52 import SrcLoc ( noSrcLoc, Located(..), mkGeneralSrcSpan,
53 unLoc, noLoc, srcLocSpan, combineSrcSpans, SrcSpan )
54 import BasicTypes ( DeprecTxt )
55 import ListSetOps ( removeDups )
56 import Util ( sortLe, notNull, isSingleton )
57 import List ( partition )
58 import IO ( openFile, IOMode(..) )
63 %************************************************************************
67 %************************************************************************
70 rnImports :: [LImportDecl RdrName]
71 -> RnM (GlobalRdrEnv, ImportAvails)
74 = do { -- PROCESS IMPORT DECLS
75 -- Do the non {- SOURCE -} ones first, so that we get a helpful
76 -- warning for {- SOURCE -} ones that are unnecessary
78 ; opt_no_prelude <- doptM Opt_NoImplicitPrelude
80 all_imports = mk_prel_imports this_mod opt_no_prelude ++ imports
81 (source, ordinary) = partition is_source_import all_imports
82 is_source_import (L _ (ImportDecl _ is_boot _ _ _)) = is_boot
84 get_imports = importsFromImportDecl this_mod
86 ; stuff1 <- mappM get_imports ordinary
87 ; stuff2 <- mappM get_imports source
91 (imp_gbl_envs, imp_avails) = unzip (stuff1 ++ stuff2)
92 gbl_env :: GlobalRdrEnv
93 gbl_env = foldr plusGlobalRdrEnv emptyGlobalRdrEnv imp_gbl_envs
95 all_avails :: ImportAvails
96 all_avails = foldr plusImportAvails emptyImportAvails imp_avails
99 ; return (gbl_env, all_avails) }
101 -- NB: opt_NoImplicitPrelude is slightly different to import Prelude ();
102 -- because the former doesn't even look at Prelude.hi for instance
103 -- declarations, whereas the latter does.
104 mk_prel_imports this_mod no_prelude
105 | moduleName this_mod == pRELUDE_Name
106 || explicit_prelude_import
110 | otherwise = [preludeImportDecl]
112 explicit_prelude_import
113 = notNull [ () | L _ (ImportDecl mod _ _ _ _) <- imports,
114 unLoc mod == pRELUDE_Name ]
118 ImportDecl (L loc pRELUDE_Name)
119 False {- Not a boot interface -}
120 False {- Not qualified -}
121 Nothing {- No "as" -}
122 Nothing {- No import list -}
124 loc = mkGeneralSrcSpan FSLIT("Implicit import declaration")
128 importsFromImportDecl :: Module
129 -> LImportDecl RdrName
130 -> RnM (GlobalRdrEnv, ImportAvails)
132 importsFromImportDecl this_mod
133 (L loc (ImportDecl loc_imp_mod_name want_boot qual_only as_mod imp_details))
137 -- If there's an error in loadInterface, (e.g. interface
138 -- file not found) we get lots of spurious errors from 'filterImports'
140 imp_mod_name = unLoc loc_imp_mod_name
141 this_mod_name = moduleName this_mod
142 doc = ppr imp_mod_name <+> ptext SLIT("is directly imported")
144 loadSrcInterface doc imp_mod_name want_boot `thenM` \ iface ->
146 -- Compiler sanity check: if the import didn't say
147 -- {-# SOURCE #-} we should not get a hi-boot file
148 WARN( not want_boot && mi_boot iface, ppr imp_mod_name )
150 -- Issue a user warning for a redundant {- SOURCE -} import
151 -- NB that we arrange to read all the ordinary imports before
152 -- any of the {- SOURCE -} imports
153 warnIf (want_boot && not (mi_boot iface))
154 (warnRedundantSourceImport imp_mod_name) `thenM_`
157 imp_mod = mi_module iface
158 deprecs = mi_deprecs iface
159 is_orph = mi_orphan iface
162 filtered_exports = filter not_this_mod (mi_exports iface)
163 not_this_mod (mod,_) = mod /= this_mod_name
164 -- If the module exports anything defined in this module, just ignore it.
165 -- Reason: otherwise it looks as if there are two local definition sites
166 -- for the thing, and an error gets reported. Easiest thing is just to
167 -- filter them out up front. This situation only arises if a module
168 -- imports itself, or another module that imported it. (Necessarily,
169 -- this invoves a loop.)
171 -- Tiresome consequence: if you say
176 -- module B( AType ) where
177 -- import {-# SOURCE #-} A( AType )
179 -- then you'll get a 'B does not export AType' message. Oh well.
181 qual_mod_name = case as_mod of
182 Nothing -> imp_mod_name
183 Just another_name -> another_name
184 imp_spec = ImportSpec { is_mod = imp_mod_name, is_qual = qual_only,
185 is_loc = loc, is_as = qual_mod_name }
188 -- Get the total imports, and filter them according to the import list
189 exportsToAvails filtered_exports `thenM` \ total_avails ->
190 filterImports iface imp_spec
191 imp_details total_avails `thenM` \ (avail_env, gbl_env) ->
194 -- Compute new transitive dependencies
196 orphans | is_orph = ASSERT( not (imp_mod_name `elem` dep_orphs deps) )
197 imp_mod_name : dep_orphs deps
198 | otherwise = dep_orphs deps
200 (dependent_mods, dependent_pkgs)
201 | isHomeModule imp_mod
202 = -- Imported module is from the home package
203 -- Take its dependent modules and
204 -- (a) remove this_mod (might be there as a hi-boot)
205 -- (b) add imp_mod itself
206 -- Take its dependent packages unchanged
207 ((imp_mod_name, want_boot) : dep_mods deps, dep_pkgs deps)
210 = -- Imported module is from another package
211 -- Dump the dependent modules
212 -- Add the package imp_mod comes from to the dependent packages
213 ASSERT( not (mi_package iface `elem` dep_pkgs deps) )
214 ([], mi_package iface : dep_pkgs deps)
216 import_all = case imp_details of
217 Just (is_hiding, ls) -- Imports are spec'd explicitly
218 | not is_hiding -> Just (not (null ls))
219 _ -> Nothing -- Everything is imported,
220 -- (or almost everything [hiding])
222 -- unqual_avails is the Avails that are visible in *unqualified* form
223 -- We need to know this so we know what to export when we see
224 -- module M ( module P ) where ...
225 -- Then we must export whatever came from P unqualified.
226 imports = ImportAvails {
227 imp_qual = unitModuleEnvByName qual_mod_name avail_env,
229 imp_mods = unitModuleEnv imp_mod (imp_mod, import_all, loc),
231 imp_dep_mods = mkModDeps dependent_mods,
232 imp_dep_pkgs = dependent_pkgs }
235 -- Complain if we import a deprecated module
236 ifOptM Opt_WarnDeprecations (
238 DeprecAll txt -> addWarn (moduleDeprec imp_mod_name txt)
242 returnM (gbl_env, imports)
244 exportsToAvails :: [IfaceExport] -> TcRnIf gbl lcl Avails
245 exportsToAvails exports
246 = do { avails_by_module <- mappM do_one exports
247 ; return (concat avails_by_module) }
249 do_one (mod_name, exports) = mapM (do_avail mod_name) exports
250 do_avail mod_nm (Avail n) = do { n' <- lookupOrig mod_nm n;
251 ; return (Avail n') }
252 do_avail mod_nm (AvailTC n ns) = do { n' <- lookupOrig mod_nm n
253 ; ns' <- mappM (lookup_sub n') ns
254 ; return (AvailTC n' ns') }
256 mod = mkPackageModule mod_nm -- Not necessarily right yet
257 lookup_sub parent occ = newGlobalBinder mod occ (Just parent) noSrcLoc
258 -- Hack alert! Notice the newGlobalBinder. It ensures that the subordinate
259 -- names record their parent; and that in turn ensures that the GlobalRdrEnv
260 -- has the correct parent for all the names in its range.
261 -- For imported things, we only suck in the binding site later, if ever.
262 -- Reason for all this:
263 -- Suppose module M exports type A.T, and constructor A.MkT
264 -- Then, we know that A.MkT is a subordinate name of A.T,
265 -- even though we aren't at the binding site of A.T
266 -- And it's important, because we may simply re-export A.T
267 -- without ever sucking in the declaration itself.
269 warnRedundantSourceImport mod_name
270 = ptext SLIT("Unnecessary {- SOURCE -} in the import of module")
271 <+> quotes (ppr mod_name)
275 %************************************************************************
277 importsFromLocalDecls
279 %************************************************************************
281 From the top-level declarations of this module produce
282 * the lexical environment
284 created by its bindings.
286 Complain about duplicate bindings
289 importsFromLocalDecls :: HsGroup RdrName
290 -> RnM (GlobalRdrEnv, ImportAvails)
291 importsFromLocalDecls group
292 = getModule `thenM` \ this_mod ->
293 getLocalDeclBinders this_mod group `thenM` \ avails ->
294 -- The avails that are returned don't include the "system" names
296 all_names :: [Name] -- All the defns; no dups eliminated
297 all_names = [name | avail <- avails, name <- availNames avail]
300 (_, dups) = removeDups compare all_names
302 -- Check for duplicate definitions
303 -- The complaint will come out as "Multiple declarations of Foo.f" because
304 -- since 'f' is in the env twice, the unQualInScope used by the error-msg
305 -- printer returns False. It seems awkward to fix, unfortunately.
306 mappM_ addDupDeclErr dups `thenM_`
308 doptM Opt_NoImplicitPrelude `thenM` \ implicit_prelude ->
310 mod_name = moduleName this_mod
311 prov = LocalDef mod_name
312 gbl_env = mkGlobalRdrEnv gres
313 gres = [ GRE { gre_name = name, gre_prov = prov}
316 -- Optimisation: filter out names for built-in syntax
317 -- They just clutter up the environment (esp tuples), and the parser
318 -- will generate Exact RdrNames for them, so the cluttered
319 -- envt is no use. To avoid doing this filter all the time,
320 -- we use -fno-implicit-prelude as a clue that the filter is
321 -- worth while. Really, it's only useful for GHC.Base and GHC.Tuple.
323 -- It's worth doing because it makes the environment smaller for
324 -- every module that imports the Prelude
326 -- Note: don't filter the gbl_env (hence avails, not avails' in
327 -- defn of gbl_env above). Stupid reason: when parsing
328 -- data type decls, the constructors start as Exact tycon-names,
329 -- and then get turned into data con names by zapping the name space;
330 -- but that stops them being Exact, so they get looked up.
331 -- Ditto in fixity decls; e.g. infix 5 :
332 -- Sigh. It doesn't matter because it only affects the Data.Tuple really.
333 -- The important thing is to trim down the exports.
335 avails' | implicit_prelude = filter not_built_in_syntax avails
337 not_built_in_syntax a = not (all isBuiltInSyntax (availNames a))
338 -- Only filter it if all the names of the avail are built-in
339 -- In particular, lists have (:) which is not built in syntax
340 -- so we don't filter it out. [Sept 03: wrong: see isBuiltInSyntax]
342 avail_env = mkAvailEnv avails'
343 imports = emptyImportAvails {
344 imp_qual = unitModuleEnv this_mod avail_env,
348 returnM (gbl_env, imports)
352 %*********************************************************
354 \subsection{Getting binders out of a declaration}
356 %*********************************************************
358 @getLocalDeclBinders@ returns the names for an @HsDecl@. It's
359 used for source code.
361 *** See "THE NAMING STORY" in HsDecls ****
364 getLocalDeclBinders :: Module -> HsGroup RdrName -> RnM [AvailInfo]
365 getLocalDeclBinders mod (HsGroup {hs_valds = val_decls,
366 hs_tyclds = tycl_decls,
367 hs_fords = foreign_decls })
368 = -- For type and class decls, we generate Global names, with
369 -- no export indicator. They need to be global because they get
370 -- permanently bound into the TyCons and Classes. They don't need
371 -- an export indicator because they are all implicitly exported.
373 mappM new_tc tycl_decls `thenM` \ tc_avails ->
374 mappM new_simple (for_hs_bndrs ++ val_hs_bndrs) `thenM` \ simple_avails ->
375 returnM (tc_avails ++ simple_avails)
377 new_simple rdr_name = newTopSrcBinder mod Nothing rdr_name `thenM` \ name ->
380 val_hs_bndrs = collectGroupBinders val_decls
381 for_hs_bndrs = [nm | L _ (ForeignImport nm _ _ _) <- foreign_decls]
384 = newTopSrcBinder mod Nothing main_rdr `thenM` \ main_name ->
385 mappM (newTopSrcBinder mod (Just main_name)) sub_rdrs `thenM` \ sub_names ->
386 returnM (AvailTC main_name (main_name : sub_names))
388 (main_rdr : sub_rdrs) = tyClDeclNames (unLoc tc_decl)
392 %************************************************************************
394 \subsection{Filtering imports}
396 %************************************************************************
398 @filterImports@ takes the @ExportEnv@ telling what the imported module makes
399 available, and filters it through the import spec (if any).
402 filterImports :: ModIface
403 -> ImportSpec -- The span for the entire import decl
404 -> Maybe (Bool, [Located (IE RdrName)]) -- Import spec; True => hiding
405 -> [AvailInfo] -- What's available
406 -> RnM (AvailEnv, -- What's imported (qualified or unqualified)
407 GlobalRdrEnv) -- Same again, but in GRE form
409 -- Complains if import spec mentions things that the module doesn't export
410 -- Warns/informs if import spec contains duplicates.
412 mkGenericRdrEnv imp_spec avails
413 = mkGlobalRdrEnv [ GRE { gre_name = name, gre_prov = Imported [imp_spec] False }
414 | avail <- avails, name <- availNames avail ]
416 filterImports iface imp_spec Nothing total_avails
417 = returnM (mkAvailEnv total_avails,
418 mkGenericRdrEnv imp_spec total_avails)
420 filterImports iface imp_spec (Just (want_hiding, import_items)) total_avails
421 = mapAndUnzipM (addLocM get_item) import_items `thenM` \ (avails_s, gres) ->
423 avails = concat avails_s
425 if not want_hiding then
426 return (mkAvailEnv avails,
427 foldr plusGlobalRdrEnv emptyGlobalRdrEnv gres)
430 hidden = availsToNameSet avails
431 keep n = not (n `elemNameSet` hidden)
432 pruned_avails = pruneAvails keep total_avails
434 return (mkAvailEnv pruned_avails,
435 mkGenericRdrEnv imp_spec pruned_avails)
438 import_fm :: OccEnv AvailInfo
439 import_fm = mkOccEnv [ (nameOccName name, avail)
440 | avail <- total_avails,
441 name <- availNames avail]
442 -- Even though availNames returns data constructors too,
443 -- they won't make any difference because naked entities like T
444 -- in an import list map to TcOccs, not VarOccs.
446 bale_out item = addErr (badImportItemErr iface imp_spec item) `thenM_`
447 returnM ([], emptyGlobalRdrEnv)
449 succeed_with :: Bool -> AvailInfo -> RnM ([AvailInfo], GlobalRdrEnv)
450 succeed_with all_explicit avail
451 = do { loc <- getSrcSpanM
453 mkGlobalRdrEnv (map (mk_gre loc) (availNames avail))) }
455 mk_gre loc name = GRE { gre_name = name,
456 gre_prov = Imported [this_imp_spec loc] (explicit name) }
457 this_imp_spec loc = imp_spec { is_loc = loc }
458 explicit name = all_explicit || name == main_name
459 main_name = availName avail
461 get_item :: IE RdrName -> RnM ([AvailInfo], GlobalRdrEnv)
462 -- Empty result for a bad item.
463 -- Singleton result is typical case.
464 -- Can have two when we are hiding, and mention C which might be
465 -- both a class and a data constructor.
466 get_item item@(IEModuleContents _)
469 get_item item@(IEThingAll tc)
470 = case check_item item of
471 Nothing -> bale_out item
472 Just avail@(AvailTC _ [n]) -> -- This occurs when you import T(..), but
473 -- only export T abstractly. The single [n]
474 -- in the AvailTC is the type or class itself
475 ifOptM Opt_WarnDodgyImports (addWarn (dodgyImportWarn tc)) `thenM_`
476 succeed_with False avail
477 Just avail -> succeed_with False avail
479 get_item item@(IEThingAbs n)
480 | want_hiding -- hiding( C )
481 -- Here the 'C' can be a data constructor
482 -- *or* a type/class, or even both
483 = case catMaybes [check_item item, check_item (IEVar data_n)] of
485 avails -> returnM (avails, emptyGlobalRdrEnv)
486 -- The GlobalRdrEnv result is irrelevant when hiding
488 data_n = setRdrNameSpace n srcDataName
491 = case check_item item of
492 Nothing -> bale_out item
493 Just avail -> succeed_with True avail
496 | isNothing maybe_in_import_avails ||
497 isNothing maybe_filtered_avail
501 = Just filtered_avail
504 wanted_occ = rdrNameOcc (ieName item)
505 maybe_in_import_avails = lookupOccEnv import_fm wanted_occ
507 Just avail = maybe_in_import_avails
508 maybe_filtered_avail = filterAvail item avail
509 Just filtered_avail = maybe_filtered_avail
513 filterAvail :: IE RdrName -- Wanted
514 -> AvailInfo -- Available
515 -> Maybe AvailInfo -- Resulting available;
516 -- Nothing if (any of the) wanted stuff isn't there
518 filterAvail ie@(IEThingWith want wants) avail@(AvailTC n ns)
519 | sub_names_ok = Just (AvailTC n (filter is_wanted ns))
520 | otherwise = Nothing
522 is_wanted name = nameOccName name `elem` wanted_occs
523 sub_names_ok = all (`elem` avail_occs) wanted_occs
524 avail_occs = map nameOccName ns
525 wanted_occs = map rdrNameOcc (want:wants)
527 filterAvail (IEThingAbs _) (AvailTC n ns) = ASSERT( n `elem` ns )
530 filterAvail (IEThingAbs _) avail@(Avail n) = Just avail -- Type synonyms
532 filterAvail (IEVar _) avail@(Avail n) = Just avail
533 filterAvail (IEVar v) avail@(AvailTC n ns) = Just (AvailTC n (filter wanted ns))
535 wanted n = nameOccName n == occ
537 -- The second equation happens if we import a class op, thus
539 -- where op is a class operation
541 filterAvail (IEThingAll _) avail@(AvailTC _ _) = Just avail
542 -- We don't complain even if the IE says T(..), but
543 -- no constrs/class ops of T are available
544 -- Instead that's caught with a warning by the caller
546 filterAvail ie avail = Nothing
550 %************************************************************************
552 \subsection{Export list processing}
554 %************************************************************************
556 Processing the export list.
558 You might think that we should record things that appear in the export
559 list as ``occurrences'' (using @addOccurrenceName@), but you'd be
560 wrong. We do check (here) that they are in scope, but there is no
561 need to slurp in their actual declaration (which is what
562 @addOccurrenceName@ forces).
564 Indeed, doing so would big trouble when compiling @PrelBase@, because
565 it re-exports @GHC@, which includes @takeMVar#@, whose type includes
566 @ConcBase.StateAndSynchVar#@, and so on...
569 type ExportAccum -- The type of the accumulating parameter of
570 -- the main worker function in exportsFromAvail
571 = ([ModuleName], -- 'module M's seen so far
572 ExportOccMap, -- Tracks exported occurrence names
573 NameSet) -- The accumulated exported stuff
574 emptyExportAccum = ([], emptyOccEnv, emptyNameSet)
576 type ExportOccMap = OccEnv (Name, IE RdrName)
577 -- Tracks what a particular exported OccName
578 -- in an export list refers to, and which item
579 -- it came from. It's illegal to export two distinct things
580 -- that have the same occurrence name
583 exportsFromAvail :: Bool -- False => no 'module M(..) where' header at all
584 -> Maybe [Located (IE RdrName)] -- Nothing => no explicit export list
586 -- Complains if two distinct exports have same OccName
587 -- Warns about identical exports.
588 -- Complains about exports items not in scope
590 exportsFromAvail explicit_mod exports
591 = do { TcGblEnv { tcg_rdr_env = rdr_env,
592 tcg_imports = imports } <- getGblEnv ;
594 -- If the module header is omitted altogether, then behave
595 -- as if the user had written "module Main(main) where..."
596 -- EXCEPT in interactive mode, when we behave as if he had
597 -- written "module Main where ..."
598 -- Reason: don't want to complain about 'main' not in scope
599 -- in interactive mode
600 ghci_mode <- getGhciMode ;
602 | explicit_mod = exports
603 | ghci_mode == Interactive = Nothing
604 | otherwise = Just [noLoc (IEVar main_RDR_Unqual)] } ;
605 exports_from_avail real_exports rdr_env imports }
608 exports_from_avail Nothing rdr_env imports
609 = -- Export all locally-defined things
610 -- We do this by filtering the global RdrEnv,
611 -- keeping only things that are locally-defined
612 return (mkNameSet [ gre_name gre
613 | gre <- globalRdrEnvElts rdr_env,
616 exports_from_avail (Just export_items) rdr_env
617 (ImportAvails { imp_qual = mod_avail_env,
618 imp_env = entity_avail_env })
619 = foldlM (exports_from_litem) emptyExportAccum
620 export_items `thenM` \ (_, _, exports) ->
624 exports_from_litem :: ExportAccum -> Located (IE RdrName) -> RnM ExportAccum
625 exports_from_litem acc = addLocM (exports_from_item acc)
627 exports_from_item :: ExportAccum -> IE RdrName -> RnM ExportAccum
628 exports_from_item acc@(mods, occs, exports) ie@(IEModuleContents mod)
629 | mod `elem` mods -- Duplicate export of M
630 = do { warn_dup_exports <- doptM Opt_WarnDuplicateExports ;
631 warnIf warn_dup_exports (dupModuleExport mod) ;
635 = case lookupModuleEnvByName mod_avail_env mod of
636 Nothing -> addErr (modExportErr mod) `thenM_`
641 new_exports = [ name | avail <- availEnvElts avail_env,
642 name <- availNames avail,
643 inScopeUnqual rdr_env name ]
646 -- This check_occs not only finds conflicts between this item
647 -- and others, but also internally within this item. That is,
648 -- if 'M.x' is in scope in several ways, we'll have several
649 -- members of mod_avails with the same OccName.
650 check_occs ie occs new_exports `thenM` \ occs' ->
651 returnM (mod:mods, occs', addListToNameSet exports new_exports)
653 exports_from_item acc@(mods, occs, exports) ie
654 = lookupGlobalOccRn (ieName ie) `thenM` \ name ->
655 if isUnboundName name then
656 returnM acc -- Avoid error cascade
658 -- Get the AvailInfo for the parent of the specified name
660 parent = nameParent name
661 avail = lookupAvailEnv entity_avail_env parent
663 -- Filter out the bits we want
664 case filterAvail ie avail of {
665 Nothing -> -- Not enough availability
666 addErr (exportItemErr ie) `thenM_`
671 -- Phew! It's OK! Now to check the occurrence stuff!
674 new_exports = availNames export_avail
676 checkForDodgyExport ie new_exports `thenM_`
677 check_occs ie occs new_exports `thenM` \ occs' ->
678 returnM (mods, occs', addListToNameSet exports new_exports)
682 -------------------------------
683 inScopeUnqual :: GlobalRdrEnv -> Name -> Bool
684 -- Checks whether the Name is in scope unqualified,
685 -- regardless of whether it's ambiguous or not
686 inScopeUnqual env n = any unQualOK (lookupGRE_Name env n)
688 -------------------------------
689 checkForDodgyExport :: IE RdrName -> [Name] -> RnM ()
690 checkForDodgyExport (IEThingAll tc) [n] = addWarn (dodgyExportWarn tc)
691 -- This occurs when you import T(..), but
692 -- only export T abstractly. The single [n]
693 -- in the AvailTC is the type or class itself
694 checkForDodgyExport _ _ = return ()
696 -------------------------------
697 check_occs :: IE RdrName -> ExportOccMap -> [Name] -> RnM ExportOccMap
698 check_occs ie occs names
699 = foldlM check occs names
702 = case lookupOccEnv occs name_occ of
703 Nothing -> returnM (extendOccEnv occs name_occ (name, ie))
706 | name == name' -- Duplicate export
707 -> do { warn_dup_exports <- doptM Opt_WarnDuplicateExports ;
708 warnIf warn_dup_exports (dupExportWarn name_occ ie ie') ;
711 | otherwise -- Same occ name but different names: an error
712 -> do { global_env <- getGlobalRdrEnv ;
713 addErr (exportClashErr global_env name name' ie ie') ;
716 name_occ = nameOccName name
719 %*********************************************************
723 %*********************************************************
726 reportDeprecations :: TcGblEnv -> RnM ()
727 reportDeprecations tcg_env
728 = ifOptM Opt_WarnDeprecations $
729 do { (eps,hpt) <- getEpsAndHpt
730 ; mapM_ (check hpt (eps_PIT eps)) all_gres }
732 used_names = findUses (tcg_dus tcg_env) emptyNameSet
733 all_gres = globalRdrEnvElts (tcg_rdr_env tcg_env)
735 check hpt pit (GRE {gre_name = name, gre_prov = Imported (imp_spec:_) _})
736 | name `elemNameSet` used_names
737 , Just deprec_txt <- lookupDeprec hpt pit name
738 = setSrcSpan (is_loc imp_spec) $
739 addWarn (sep [ptext SLIT("Deprecated use of") <+>
740 occNameFlavour (nameOccName name) <+>
745 name_mod = nameModuleName name
746 imp_mod = is_mod imp_spec
747 imp_msg = ptext SLIT("imported from") <+> ppr imp_mod <> extra
748 extra | imp_mod == name_mod = empty
749 | otherwise = ptext SLIT(", but defined in") <+> ppr name_mod
751 check hpt pit ok_gre = returnM () -- Local, or not used, or not deprectated
752 -- The Imported pattern-match: don't deprecate locally defined names
753 -- For a start, we may be exporting a deprecated thing
754 -- Also we may use a deprecated thing in the defn of another
755 -- deprecated things. We may even use a deprecated thing in
756 -- the defn of a non-deprecated thing, when changing a module's
759 lookupDeprec :: HomePackageTable -> PackageIfaceTable
760 -> Name -> Maybe DeprecTxt
761 lookupDeprec hpt pit n
762 = case lookupIface hpt pit (nameModule n) of
763 Just iface -> mi_dep_fn iface n `seqMaybe` -- Bleat if the thing, *or
764 mi_dep_fn iface (nameParent n) -- its parent*, is deprec'd
766 | isWiredInName n -> Nothing
767 -- We have not necessarily loaded the .hi file for a
768 -- wired-in name (yet), although we *could*.
769 -- And we never deprecate them
771 | otherwise -> pprPanic "lookupDeprec" (ppr n)
772 -- By now all the interfaces should have been loaded
774 gre_is_used :: NameSet -> GlobalRdrElt -> Bool
775 gre_is_used used_names gre = gre_name gre `elemNameSet` used_names
778 %*********************************************************
782 %*********************************************************
785 reportUnusedNames :: TcGblEnv -> RnM ()
786 reportUnusedNames gbl_env
787 = do { warnUnusedTopBinds unused_locals
788 ; warnUnusedModules unused_imp_mods
789 ; warnUnusedImports unused_imports
790 ; warnDuplicateImports dup_imps
791 ; printMinimalImports minimal_imports }
793 used_names, all_used_names :: NameSet
794 used_names = findUses (tcg_dus gbl_env) emptyNameSet
795 all_used_names = used_names `unionNameSets`
796 mkNameSet (mapCatMaybes nameParent_maybe (nameSetToList used_names))
797 -- A use of C implies a use of T,
798 -- if C was brought into scope by T(..) or T(C)
800 -- Collect the defined names from the in-scope environment
801 defined_names :: [GlobalRdrElt]
802 defined_names = globalRdrEnvElts (tcg_rdr_env gbl_env)
804 -- Note that defined_and_used, defined_but_not_used
805 -- are both [GRE]; that's why we need defined_and_used
806 -- rather than just all_used_names
807 defined_and_used, defined_but_not_used :: [GlobalRdrElt]
808 (defined_and_used, defined_but_not_used)
809 = partition (gre_is_used all_used_names) defined_names
811 -- Find the duplicate imports
812 dup_imps = filter is_dup defined_and_used
813 is_dup (GRE {gre_prov = Imported imp_spec True}) = not (isSingleton imp_spec)
816 -- Filter out the ones that are
817 -- (a) defined in this module, and
818 -- (b) not defined by a 'deriving' clause
819 -- The latter have an Internal Name, so we can filter them out easily
820 unused_locals :: [GlobalRdrElt]
821 unused_locals = filter is_unused_local defined_but_not_used
822 is_unused_local :: GlobalRdrElt -> Bool
823 is_unused_local gre = isLocalGRE gre && isExternalName (gre_name gre)
825 unused_imports :: [GlobalRdrElt]
826 unused_imports = filter unused_imp defined_but_not_used
827 unused_imp (GRE {gre_prov = Imported imp_specs True})
828 = not (all (module_unused . is_mod) imp_specs)
829 -- Don't complain about unused imports if we've already said the
830 -- entire import is unused
831 unused_imp other = False
833 -- To figure out the minimal set of imports, start with the things
834 -- that are in scope (i.e. in gbl_env). Then just combine them
835 -- into a bunch of avails, so they are properly grouped
836 minimal_imports :: FiniteMap ModuleName AvailEnv
837 minimal_imports0 = emptyFM
838 minimal_imports1 = foldr add_name minimal_imports0 defined_and_used
839 minimal_imports = foldr add_inst_mod minimal_imports1 direct_import_mods
840 -- The last line makes sure that we retain all direct imports
841 -- even if we import nothing explicitly.
842 -- It's not necessarily redundant to import such modules. Consider
846 -- The import M() is not *necessarily* redundant, even if
847 -- we suck in no instance decls from M (e.g. it contains
848 -- no instance decls, or This contains no code). It may be
849 -- that we import M solely to ensure that M's orphan instance
850 -- decls (or those in its imports) are visible to people who
851 -- import This. Sigh.
852 -- There's really no good way to detect this, so the error message
853 -- in RnEnv.warnUnusedModules is weakened instead
855 -- We've carefully preserved the provenance so that we can
856 -- construct minimal imports that import the name by (one of)
857 -- the same route(s) as the programmer originally did.
858 add_name (GRE {gre_name = n, gre_prov = Imported imp_specs _}) acc
859 = addToFM_C plusAvailEnv acc (is_mod (head imp_specs))
860 (unitAvailEnv (mk_avail n (nameParent_maybe n)))
864 -- n is the name of the thing, p is the name of its parent
865 mk_avail n (Just p) = AvailTC p [p,n]
866 mk_avail n Nothing | isTcOcc (nameOccName n) = AvailTC n [n]
867 | otherwise = Avail n
869 add_inst_mod (mod,_,_) acc
870 | mod_name `elemFM` acc = acc -- We import something already
871 | otherwise = addToFM acc mod_name emptyAvailEnv
873 mod_name = moduleName mod
874 -- Add an empty collection of imports for a module
875 -- from which we have sucked only instance decls
877 imports = tcg_imports gbl_env
879 direct_import_mods :: [(Module, Maybe Bool, SrcSpan)]
880 -- See the type of the imp_mods for this triple
881 direct_import_mods = moduleEnvElts (imp_mods imports)
883 -- unused_imp_mods are the directly-imported modules
884 -- that are not mentioned in minimal_imports1
885 -- [Note: not 'minimal_imports', because that includes directly-imported
886 -- modules even if we use nothing from them; see notes above]
887 unused_imp_mods = [(mod_name,loc) | (mod,imp,loc) <- direct_import_mods,
888 let mod_name = moduleName mod,
889 not (mod_name `elemFM` minimal_imports1),
890 mod_name /= pRELUDE_Name,
892 -- The Just False part is not to complain about
893 -- import M (), which is an idiom for importing
894 -- instance declarations
896 module_unused :: ModuleName -> Bool
897 module_unused mod = any (((==) mod) . fst) unused_imp_mods
899 ---------------------
900 warnDuplicateImports :: [GlobalRdrElt] -> RnM ()
901 warnDuplicateImports gres
902 = ifOptM Opt_WarnUnusedImports (mapM_ warn gres)
904 warn (GRE { gre_name = name, gre_prov = Imported imps _ })
905 = addWarn ((quotes (ppr name) <+> ptext SLIT("is imported more than once:"))
906 $$ nest 2 (vcat (map ppr imps)))
909 -- ToDo: deal with original imports with 'qualified' and 'as M' clauses
910 printMinimalImports :: FiniteMap ModuleName AvailEnv -- Minimal imports
912 printMinimalImports imps
913 = ifOptM Opt_D_dump_minimal_imports $ do {
915 mod_ies <- mappM to_ies (fmToList imps) ;
916 this_mod <- getModule ;
917 rdr_env <- getGlobalRdrEnv ;
918 ioToTcRn (do { h <- openFile (mkFilename this_mod) WriteMode ;
919 printForUser h (unQualInScope rdr_env)
920 (vcat (map ppr_mod_ie mod_ies)) })
923 mkFilename this_mod = moduleNameUserString (moduleName this_mod) ++ ".imports"
924 ppr_mod_ie (mod_name, ies)
925 | mod_name == pRELUDE_Name
927 | null ies -- Nothing except instances comes from here
928 = ptext SLIT("import") <+> ppr mod_name <> ptext SLIT("() -- Instances only")
930 = ptext SLIT("import") <+> ppr mod_name <>
931 parens (fsep (punctuate comma (map ppr ies)))
933 to_ies (mod, avail_env) = mappM to_ie (availEnvElts avail_env) `thenM` \ ies ->
936 to_ie :: AvailInfo -> RnM (IE Name)
937 -- The main trick here is that if we're importing all the constructors
938 -- we want to say "T(..)", but if we're importing only a subset we want
939 -- to say "T(A,B,C)". So we have to find out what the module exports.
940 to_ie (Avail n) = returnM (IEVar n)
941 to_ie (AvailTC n [m]) = ASSERT( n==m )
942 returnM (IEThingAbs n)
944 = loadSrcInterface doc n_mod False `thenM` \ iface ->
945 case [xs | (m,as) <- mi_exports iface,
948 x == nameOccName n] of
949 [xs] | all_used xs -> returnM (IEThingAll n)
950 | otherwise -> returnM (IEThingWith n (filter (/= n) ns))
951 other -> pprTrace "to_ie" (ppr n <+> ppr n_mod <+> ppr other) $
954 all_used avail_occs = all (`elem` map nameOccName ns) avail_occs
955 doc = text "Compute minimal imports from" <+> ppr n
956 n_mod = nameModuleName n
960 %************************************************************************
964 %************************************************************************
967 badImportItemErr iface imp_spec ie
968 = sep [ptext SLIT("Module"), quotes (ppr (is_mod imp_spec)), source_import,
969 ptext SLIT("does not export"), quotes (ppr ie)]
971 source_import | mi_boot iface = ptext SLIT("(hi-boot interface)")
974 dodgyImportWarn item = dodgyMsg (ptext SLIT("import")) item
975 dodgyExportWarn item = dodgyMsg (ptext SLIT("export")) item
978 = sep [ ptext SLIT("The") <+> kind <+> ptext SLIT("item") <+> quotes (ppr (IEThingAll tc)),
979 ptext SLIT("suggests that") <+> quotes (ppr tc) <+> ptext SLIT("has constructor or class methods"),
980 ptext SLIT("but it has none; it is a type synonym or abstract type or class") ]
983 = hsep [ ptext SLIT("Unknown module in export list: module"), quotes (ppr mod)]
985 exportItemErr export_item
986 = sep [ ptext SLIT("The export item") <+> quotes (ppr export_item),
987 ptext SLIT("attempts to export constructors or class methods that are not visible here") ]
989 exportClashErr global_env name1 name2 ie1 ie2
990 = vcat [ ptext SLIT("Conflicting exports for") <+> quotes (ppr occ) <> colon
991 , ppr_export ie1 name1
992 , ppr_export ie2 name2 ]
994 occ = nameOccName name1
995 ppr_export ie name = nest 2 (quotes (ppr ie) <+> ptext SLIT("exports") <+>
996 quotes (ppr name) <+> pprNameProvenance (get_gre name))
998 -- get_gre finds a GRE for the Name, so that we can show its provenance
1000 = case lookupGRE_Name global_env name of
1002 [] -> pprPanic "exportClashErr" (ppr name)
1004 addDupDeclErr :: [Name] -> TcRn ()
1006 = addErrAt big_loc $
1007 vcat [ptext SLIT("Multiple declarations of") <+> quotes (ppr name1),
1008 ptext SLIT("Declared at:") <+> vcat (map ppr sorted_locs)]
1010 locs = map nameSrcLoc names
1011 big_loc = foldr1 combineSrcSpans (map srcLocSpan locs)
1013 sorted_locs = sortLe (<=) (sortLe (<=) locs)
1015 dupExportWarn occ_name ie1 ie2
1016 = hsep [quotes (ppr occ_name),
1017 ptext SLIT("is exported by"), quotes (ppr ie1),
1018 ptext SLIT("and"), quotes (ppr ie2)]
1021 = hsep [ptext SLIT("Duplicate"),
1022 quotes (ptext SLIT("Module") <+> ppr mod),
1023 ptext SLIT("in export list")]
1025 moduleDeprec mod txt
1026 = sep [ ptext SLIT("Module") <+> quotes (ppr mod) <+> ptext SLIT("is deprecated:"),