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, mkModDeps, exportsToAvails
12 #include "HsVersions.h"
14 import CmdLineOpts ( DynFlag(..) )
15 import HsSyn ( IE(..), ieName, ImportDecl(..), LImportDecl,
16 ForeignDecl(..), HsGroup(..),
17 collectGroupBinders, tyClDeclNames
20 import IfaceEnv ( lookupOrig, newGlobalBinder )
21 import LoadIface ( loadSrcInterface )
25 import PrelNames ( pRELUDE_Name, isBuiltInSyntaxName, isUnboundName,
27 import Module ( Module, ModuleName, moduleName, mkPackageModule,
28 moduleNameUserString, isHomeModule,
29 unitModuleEnvByName, unitModuleEnv,
30 lookupModuleEnvByName, moduleEnvElts )
31 import Name ( Name, nameSrcLoc, nameOccName, nameModuleName,
32 nameParent, nameParent_maybe, isExternalName )
35 import OccName ( OccName, srcDataName, isTcOcc )
36 import HscTypes ( GenAvailInfo(..), AvailInfo, Avails, GhciMode(..),
37 IsBootInterface, IfaceExport,
38 availName, availNames, availsToNameSet, unQualInScope,
39 Deprecs(..), ModIface(..), Dependencies(..)
41 import RdrName ( RdrName, rdrNameOcc, setRdrNameSpace,
42 GlobalRdrEnv, mkGlobalRdrEnv, GlobalRdrElt(..),
43 emptyGlobalRdrEnv, plusGlobalRdrEnv, globalRdrEnvElts,
44 unQualOK, lookupGRE_Name,
45 Provenance(..), ImportSpec(..),
46 isLocalGRE, pprNameProvenance )
48 import Maybes ( isJust, isNothing, catMaybes, mapCatMaybes )
49 import SrcLoc ( noSrcLoc, Located(..), mkGeneralSrcSpan,
51 import ListSetOps ( removeDups )
52 import Util ( sortLt, notNull )
53 import List ( partition, insert )
54 import IO ( openFile, IOMode(..) )
59 %************************************************************************
63 %************************************************************************
66 rnImports :: [LImportDecl RdrName]
67 -> RnM (GlobalRdrEnv, ImportAvails)
70 = -- PROCESS IMPORT DECLS
71 -- Do the non {- SOURCE -} ones first, so that we get a helpful
72 -- warning for {- SOURCE -} ones that are unnecessary
73 getModule `thenM` \ this_mod ->
74 doptM Opt_NoImplicitPrelude `thenM` \ opt_no_prelude ->
76 all_imports = mk_prel_imports this_mod opt_no_prelude ++ imports
77 (source, ordinary) = partition is_source_import all_imports
78 is_source_import (L _ (ImportDecl _ is_boot _ _ _)) = is_boot
80 get_imports = importsFromImportDecl this_mod
82 mappM get_imports ordinary `thenM` \ stuff1 ->
83 mappM get_imports source `thenM` \ stuff2 ->
87 (imp_gbl_envs, imp_avails) = unzip (stuff1 ++ stuff2)
88 gbl_env :: GlobalRdrEnv
89 gbl_env = foldr plusGlobalRdrEnv emptyGlobalRdrEnv imp_gbl_envs
91 all_avails :: ImportAvails
92 all_avails = foldr plusImportAvails emptyImportAvails imp_avails
95 returnM (gbl_env, all_avails)
97 -- NB: opt_NoImplicitPrelude is slightly different to import Prelude ();
98 -- because the former doesn't even look at Prelude.hi for instance
99 -- declarations, whereas the latter does.
100 mk_prel_imports this_mod no_prelude
101 | moduleName this_mod == pRELUDE_Name
102 || explicit_prelude_import
106 | otherwise = [preludeImportDecl]
108 explicit_prelude_import
109 = notNull [ () | L _ (ImportDecl mod _ _ _ _) <- imports,
110 unLoc mod == pRELUDE_Name ]
114 ImportDecl (L loc pRELUDE_Name)
115 False {- Not a boot interface -}
116 False {- Not qualified -}
117 Nothing {- No "as" -}
118 Nothing {- No import list -}
120 loc = mkGeneralSrcSpan FSLIT("Implicit import declaration")
124 importsFromImportDecl :: Module
125 -> LImportDecl RdrName
126 -> RnM (GlobalRdrEnv, ImportAvails)
128 importsFromImportDecl this_mod
129 (L loc (ImportDecl loc_imp_mod_name want_boot qual_only as_mod imp_details))
133 -- If there's an error in loadInterface, (e.g. interface
134 -- file not found) we get lots of spurious errors from 'filterImports'
136 imp_mod_name = unLoc loc_imp_mod_name
137 this_mod_name = moduleName this_mod
138 doc = ppr imp_mod_name <+> ptext SLIT("is directly imported")
140 loadSrcInterface doc imp_mod_name want_boot `thenM` \ iface ->
142 -- Compiler sanity check: if the import didn't say
143 -- {-# SOURCE #-} we should not get a hi-boot file
144 WARN( not want_boot && mi_boot iface, ppr imp_mod_name )
146 -- Issue a user warning for a redundant {- SOURCE -} import
147 -- NB that we arrange to read all the ordinary imports before
148 -- any of the {- SOURCE -} imports
149 warnIf (want_boot && not (mi_boot iface))
150 (warnRedundantSourceImport imp_mod_name) `thenM_`
153 imp_mod = mi_module iface
154 deprecs = mi_deprecs iface
155 is_orph = mi_orphan iface
158 filtered_exports = filter not_this_mod (mi_exports iface)
159 not_this_mod (mod,_) = mod /= this_mod_name
160 -- If the module exports anything defined in this module, just ignore it.
161 -- Reason: otherwise it looks as if there are two local definition sites
162 -- for the thing, and an error gets reported. Easiest thing is just to
163 -- filter them out up front. This situation only arises if a module
164 -- imports itself, or another module that imported it. (Necessarily,
165 -- this invoves a loop.)
167 -- Tiresome consequence: if you say
172 -- module B( AType ) where
173 -- import {-# SOURCE #-} A( AType )
175 -- then you'll get a 'B does not export AType' message. Oh well.
177 exportsToAvails filtered_exports `thenM` \ avails ->
179 -- Filter the imports according to the import list
180 filterImports imp_mod want_boot imp_details avails `thenM` \ (filtered_avails, explicits) ->
183 -- Compute new transitive dependencies
184 orphans | is_orph = insert imp_mod_name (dep_orphs deps)
185 | otherwise = dep_orphs deps
187 (dependent_mods, dependent_pkgs)
188 | isHomeModule imp_mod
189 = -- Imported module is from the home package
190 -- Take its dependent modules and
191 -- (a) remove this_mod (might be there as a hi-boot)
192 -- (b) add imp_mod itself
193 -- Take its dependent packages unchanged
194 ((imp_mod_name, want_boot) : filter not_self (dep_mods deps), dep_pkgs deps)
197 = -- Imported module is from another package
198 -- Dump the dependent modules
199 -- Add the package imp_mod comes from to the dependent packages
201 ([], insert (mi_package iface) (dep_pkgs deps))
203 not_self (m, _) = m /= this_mod_name
205 import_all = case imp_details of
206 Just (is_hiding, ls) -- Imports are spec'd explicitly
207 | not is_hiding -> Just (not (null ls))
208 _ -> Nothing -- Everything is imported,
209 -- (or almost everything [hiding])
211 qual_mod_name = case as_mod of
212 Nothing -> imp_mod_name
213 Just another_name -> another_name
215 -- unqual_avails is the Avails that are visible in *unqualified* form
216 -- We need to know this so we know what to export when we see
217 -- module M ( module P ) where ...
218 -- Then we must export whatever came from P unqualified.
219 imp_spec = ImportSpec { is_mod = imp_mod_name, is_qual = qual_only,
220 is_loc = loc, is_as = qual_mod_name }
221 mk_deprec = mi_dep_fn iface
222 gres = [ GRE { gre_name = name,
223 gre_prov = Imported [imp_spec] (name `elemNameSet` explicits),
224 gre_deprec = mk_deprec name }
225 | avail <- filtered_avails, name <- availNames avail ]
226 gbl_env = mkGlobalRdrEnv gres
228 avail_env = mkAvailEnv filtered_avails
229 imports = ImportAvails {
230 imp_qual = unitModuleEnvByName qual_mod_name avail_env,
232 imp_mods = unitModuleEnv imp_mod (imp_mod, import_all),
234 imp_dep_mods = mkModDeps dependent_mods,
235 imp_dep_pkgs = dependent_pkgs }
238 -- Complain if we import a deprecated module
239 ifOptM Opt_WarnDeprecations (
241 DeprecAll txt -> addWarn (moduleDeprec imp_mod_name txt)
245 returnM (gbl_env, imports)
247 exportsToAvails :: [IfaceExport] -> TcRnIf gbl lcl Avails
248 exportsToAvails exports
249 = do { avails_by_module <- mappM do_one exports
250 ; return (concat avails_by_module) }
252 do_one (mod_name, exports) = mapM (do_avail mod_name) exports
253 do_avail mod_nm (Avail n) = do { n' <- lookupOrig mod_nm n;
254 ; return (Avail n') }
255 do_avail mod_nm (AvailTC n ns) = do { n' <- lookupOrig mod_nm n
256 ; ns' <- mappM (lookup_sub n') ns
257 ; return (AvailTC n' ns') }
259 mod = mkPackageModule mod_nm -- Not necessarily right yet
260 lookup_sub parent occ = newGlobalBinder mod occ (Just parent) noSrcLoc
261 -- Hack alert! Notice the newGlobalBinder. It ensures that the subordinate
262 -- names record their parent; and that in turn ensures that the GlobalRdrEnv
263 -- has the correct parent for all the names in its range.
264 -- For imported things, we only suck in the binding site later, if ever.
265 -- Reason for all this:
266 -- Suppose module M exports type A.T, and constructor A.MkT
267 -- Then, we know that A.MkT is a subordinate name of A.T,
268 -- even though we aren't at the binding site of A.T
269 -- And it's important, because we may simply re-export A.T
270 -- without ever sucking in the declaration itself.
272 warnRedundantSourceImport mod_name
273 = ptext SLIT("Unnecessary {- SOURCE -} in the import of module")
274 <+> quotes (ppr mod_name)
278 %************************************************************************
280 importsFromLocalDecls
282 %************************************************************************
284 From the top-level declarations of this module produce
285 * the lexical environment
287 created by its bindings.
289 Complain about duplicate bindings
292 importsFromLocalDecls :: HsGroup RdrName
293 -> RnM (GlobalRdrEnv, ImportAvails)
294 importsFromLocalDecls group
295 = getModule `thenM` \ this_mod ->
296 getLocalDeclBinders this_mod group `thenM` \ avails ->
297 -- The avails that are returned don't include the "system" names
299 all_names :: [Name] -- All the defns; no dups eliminated
300 all_names = [name | avail <- avails, name <- availNames avail]
303 (_, dups) = removeDups compare all_names
305 -- Check for duplicate definitions
306 -- The complaint will come out as "Multiple declarations of Foo.f" because
307 -- since 'f' is in the env twice, the unQualInScope used by the error-msg
308 -- printer returns False. It seems awkward to fix, unfortunately.
309 mappM_ (addErr . dupDeclErr) dups `thenM_`
311 doptM Opt_NoImplicitPrelude `thenM` \ implicit_prelude ->
313 mod_name = moduleName this_mod
314 prov = LocalDef mod_name
315 gbl_env = mkGlobalRdrEnv gres
316 gres = [ GRE { gre_name = name, gre_prov = prov, gre_deprec = Nothing}
318 -- gre_deprecs = Nothing: don't deprecate locally defined names
319 -- For a start, we may be exporting a deprecated thing
320 -- Also we may use a deprecated thing in the defn of another
321 -- deprecated things. We may even use a deprecated thing in
322 -- the defn of a non-deprecated thing, when changing a module's
326 -- Optimisation: filter out names for built-in syntax
327 -- They just clutter up the environment (esp tuples), and the parser
328 -- will generate Exact RdrNames for them, so the cluttered
329 -- envt is no use. To avoid doing this filter all the time,
330 -- we use -fno-implicit-prelude as a clue that the filter is
331 -- worth while. Really, it's only useful for GHC.Base and GHC.Tuple.
333 -- It's worth doing because it makes the environment smaller for
334 -- every module that imports the Prelude
336 -- Note: don't filter the gbl_env (hence avails, not avails' in
337 -- defn of gbl_env above). Stupid reason: when parsing
338 -- data type decls, the constructors start as Exact tycon-names,
339 -- and then get turned into data con names by zapping the name space;
340 -- but that stops them being Exact, so they get looked up.
341 -- Ditto in fixity decls; e.g. infix 5 :
342 -- Sigh. It doesn't matter because it only affects the Data.Tuple really.
343 -- The important thing is to trim down the exports.
345 avails' | implicit_prelude = filter not_built_in_syntax avails
347 not_built_in_syntax a = not (all isBuiltInSyntaxName (availNames a))
348 -- Only filter it if all the names of the avail are built-in
349 -- In particular, lists have (:) which is not built in syntax
350 -- so we don't filter it out. [Sept 03: wrong: see isBuiltInSyntaxName]
352 avail_env = mkAvailEnv avails'
353 imports = emptyImportAvails {
354 imp_qual = unitModuleEnv this_mod avail_env,
358 returnM (gbl_env, imports)
362 %*********************************************************
364 \subsection{Getting binders out of a declaration}
366 %*********************************************************
368 @getLocalDeclBinders@ returns the names for an @HsDecl@. It's
369 used for source code.
371 *** See "THE NAMING STORY" in HsDecls ****
374 getLocalDeclBinders :: Module -> HsGroup RdrName -> RnM [AvailInfo]
375 getLocalDeclBinders mod (HsGroup {hs_valds = val_decls,
376 hs_tyclds = tycl_decls,
377 hs_fords = foreign_decls })
378 = -- For type and class decls, we generate Global names, with
379 -- no export indicator. They need to be global because they get
380 -- permanently bound into the TyCons and Classes. They don't need
381 -- an export indicator because they are all implicitly exported.
383 mappM new_tc tycl_decls `thenM` \ tc_avails ->
384 mappM new_simple (for_hs_bndrs ++ val_hs_bndrs) `thenM` \ simple_avails ->
385 returnM (tc_avails ++ simple_avails)
387 new_simple rdr_name = newTopSrcBinder mod Nothing rdr_name `thenM` \ name ->
390 val_hs_bndrs = collectGroupBinders val_decls
391 for_hs_bndrs = [nm | L _ (ForeignImport nm _ _ _) <- foreign_decls]
394 = newTopSrcBinder mod Nothing main_rdr `thenM` \ main_name ->
395 mappM (newTopSrcBinder mod (Just main_name)) sub_rdrs `thenM` \ sub_names ->
396 returnM (AvailTC main_name (main_name : sub_names))
398 (main_rdr : sub_rdrs) = tyClDeclNames (unLoc tc_decl)
402 %************************************************************************
404 \subsection{Filtering imports}
406 %************************************************************************
408 @filterImports@ takes the @ExportEnv@ telling what the imported module makes
409 available, and filters it through the import spec (if any).
412 filterImports :: Module -- The module being imported
413 -> IsBootInterface -- Tells whether it's a {-# SOURCE #-} import
414 -> Maybe (Bool, [Located (IE RdrName)]) -- Import spec; True => hiding
415 -> [AvailInfo] -- What's available
416 -> RnM ([AvailInfo], -- What's imported
417 NameSet) -- What was imported explicitly
419 -- Complains if import spec mentions things that the module doesn't export
420 -- Warns/informs if import spec contains duplicates.
421 filterImports mod from Nothing imports
422 = returnM (imports, emptyNameSet)
424 filterImports mod from (Just (want_hiding, import_items)) total_avails
425 = mappM (addLocM get_item) import_items `thenM` \ avails_w_explicits_s ->
427 (item_avails, explicits_s) = unzip (concat avails_w_explicits_s)
428 explicits = foldl addListToNameSet emptyNameSet explicits_s
431 let -- All imported; item_avails to be hidden
432 hidden = availsToNameSet item_avails
433 keep n = not (n `elemNameSet` hidden)
435 returnM (pruneAvails keep total_avails, emptyNameSet)
437 -- Just item_avails imported; nothing to be hidden
438 returnM (item_avails, explicits)
440 import_fm :: FiniteMap OccName AvailInfo
441 import_fm = listToFM [ (nameOccName name, avail)
442 | avail <- total_avails,
443 name <- availNames avail]
444 -- Even though availNames returns data constructors too,
445 -- they won't make any difference because naked entities like T
446 -- in an import list map to TcOccs, not VarOccs.
448 bale_out item = addErr (badImportItemErr mod from item) `thenM_`
451 get_item :: IE RdrName -> RnM [(AvailInfo, [Name])]
452 -- Empty list for a bad item.
453 -- Singleton is typical case.
454 -- Can have two when we are hiding, and mention C which might be
455 -- both a class and a data constructor.
456 -- The [Name] is the list of explicitly-mentioned names
457 get_item item@(IEModuleContents _) = bale_out item
459 get_item item@(IEThingAll tc)
460 = case check_item item of
461 Nothing -> bale_out item
462 Just avail@(AvailTC _ [n]) -> -- This occurs when you import T(..), but
463 -- only export T abstractly. The single [n]
464 -- in the AvailTC is the type or class itself
465 ifOptM Opt_WarnMisc (addWarn (dodgyImportWarn mod tc)) `thenM_`
466 returnM [(avail, [availName avail])]
467 Just avail -> returnM [(avail, [availName avail])]
469 get_item item@(IEThingAbs n)
470 | want_hiding -- hiding( C )
471 -- Here the 'C' can be a data constructor *or* a type/class
472 = case catMaybes [check_item item, check_item (IEVar data_n)] of
474 avails -> returnM [(a, []) | a <- avails]
475 -- The 'explicits' list is irrelevant when hiding
477 data_n = setRdrNameSpace n srcDataName
480 = case check_item item of
481 Nothing -> bale_out item
482 Just avail -> returnM [(avail, availNames avail)]
485 | isNothing maybe_in_import_avails ||
486 isNothing maybe_filtered_avail
490 = Just filtered_avail
493 wanted_occ = rdrNameOcc (ieName item)
494 maybe_in_import_avails = lookupFM import_fm wanted_occ
496 Just avail = maybe_in_import_avails
497 maybe_filtered_avail = filterAvail item avail
498 Just filtered_avail = maybe_filtered_avail
502 filterAvail :: IE RdrName -- Wanted
503 -> AvailInfo -- Available
504 -> Maybe AvailInfo -- Resulting available;
505 -- Nothing if (any of the) wanted stuff isn't there
507 filterAvail ie@(IEThingWith want wants) avail@(AvailTC n ns)
508 | sub_names_ok = Just (AvailTC n (filter is_wanted ns))
509 | otherwise = Nothing
511 is_wanted name = nameOccName name `elem` wanted_occs
512 sub_names_ok = all (`elem` avail_occs) wanted_occs
513 avail_occs = map nameOccName ns
514 wanted_occs = map rdrNameOcc (want:wants)
516 filterAvail (IEThingAbs _) (AvailTC n ns) = ASSERT( n `elem` ns )
519 filterAvail (IEThingAbs _) avail@(Avail n) = Just avail -- Type synonyms
521 filterAvail (IEVar _) avail@(Avail n) = Just avail
522 filterAvail (IEVar v) avail@(AvailTC n ns) = Just (AvailTC n (filter wanted ns))
524 wanted n = nameOccName n == occ
526 -- The second equation happens if we import a class op, thus
528 -- where op is a class operation
530 filterAvail (IEThingAll _) avail@(AvailTC _ _) = Just avail
531 -- We don't complain even if the IE says T(..), but
532 -- no constrs/class ops of T are available
533 -- Instead that's caught with a warning by the caller
535 filterAvail ie avail = Nothing
539 %************************************************************************
541 \subsection{Export list processing}
543 %************************************************************************
545 Processing the export list.
547 You might think that we should record things that appear in the export
548 list as ``occurrences'' (using @addOccurrenceName@), but you'd be
549 wrong. We do check (here) that they are in scope, but there is no
550 need to slurp in their actual declaration (which is what
551 @addOccurrenceName@ forces).
553 Indeed, doing so would big trouble when compiling @PrelBase@, because
554 it re-exports @GHC@, which includes @takeMVar#@, whose type includes
555 @ConcBase.StateAndSynchVar#@, and so on...
558 type ExportAccum -- The type of the accumulating parameter of
559 -- the main worker function in exportsFromAvail
560 = ([ModuleName], -- 'module M's seen so far
561 ExportOccMap, -- Tracks exported occurrence names
562 AvailEnv) -- The accumulated exported stuff, kept in an env
563 -- so we can common-up related AvailInfos
564 emptyExportAccum = ([], emptyFM, emptyAvailEnv)
566 type ExportOccMap = FiniteMap OccName (Name, IE RdrName)
567 -- Tracks what a particular exported OccName
568 -- in an export list refers to, and which item
569 -- it came from. It's illegal to export two distinct things
570 -- that have the same occurrence name
573 exportsFromAvail :: Bool -- False => no 'module M(..) where' header at all
574 -> Maybe [Located (IE RdrName)] -- Nothing => no explicit export list
576 -- Complains if two distinct exports have same OccName
577 -- Warns about identical exports.
578 -- Complains about exports items not in scope
580 exportsFromAvail explicit_mod exports
581 = do { TcGblEnv { tcg_rdr_env = rdr_env,
582 tcg_imports = imports } <- getGblEnv ;
584 -- If the module header is omitted altogether, then behave
585 -- as if the user had written "module Main(main) where..."
586 -- EXCEPT in interactive mode, when we behave as if he had
587 -- written "module Main where ..."
588 -- Reason: don't want to complain about 'main' not in scope
589 -- in interactive mode
590 ghci_mode <- getGhciMode ;
592 | explicit_mod = exports
593 | ghci_mode == Interactive = Nothing
594 | otherwise = Just [noLoc (IEVar main_RDR_Unqual)] } ;
595 exports_from_avail real_exports rdr_env imports }
598 exports_from_avail Nothing rdr_env
599 imports@(ImportAvails { imp_env = entity_avail_env })
600 = -- Export all locally-defined things
601 -- We do this by filtering the global RdrEnv,
602 -- keeping only things that are (a) qualified,
603 -- (b) locally defined, (c) a 'main' name
604 -- Then we look up in the entity-avail-env
605 return [ lookupAvailEnv entity_avail_env name
606 | gre <- globalRdrEnvElts rdr_env,
608 let name = gre_name gre,
609 isNothing (nameParent_maybe name) -- Main things only
612 exports_from_avail (Just export_items) rdr_env
613 (ImportAvails { imp_qual = mod_avail_env,
614 imp_env = entity_avail_env })
615 = foldlM (exports_from_litem) emptyExportAccum
616 export_items `thenM` \ (_, _, export_avail_map) ->
617 returnM (nameEnvElts export_avail_map)
620 exports_from_litem :: ExportAccum -> Located (IE RdrName) -> RnM ExportAccum
621 exports_from_litem acc = addLocM (exports_from_item acc)
623 exports_from_item :: ExportAccum -> IE RdrName -> RnM ExportAccum
624 exports_from_item acc@(mods, occs, avails) ie@(IEModuleContents mod)
625 | mod `elem` mods -- Duplicate export of M
626 = do { warn_dup_exports <- doptM Opt_WarnDuplicateExports ;
627 warnIf warn_dup_exports (dupModuleExport mod) ;
631 = case lookupModuleEnvByName mod_avail_env mod of
632 Nothing -> addErr (modExportErr mod) `thenM_`
637 mod_avails = [ filtered_avail
638 | avail <- availEnvElts avail_env,
639 let mb_avail = filter_unqual rdr_env avail,
641 let Just filtered_avail = mb_avail]
643 avails' = foldl addAvail avails mod_avails
645 -- This check_occs not only finds conflicts between this item
646 -- and others, but also internally within this item. That is,
647 -- if 'M.x' is in scope in several ways, we'll have several
648 -- members of mod_avails with the same OccName.
650 foldlM (check_occs ie) occs mod_avails `thenM` \ occs' ->
651 returnM (mod:mods, occs', avails')
653 exports_from_item acc@(mods, occs, avails) 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!
672 checkForDodgyExport ie avail `thenM_`
673 check_occs ie occs export_avail `thenM` \ occs' ->
674 returnM (mods, occs', addAvail avails export_avail)
678 -------------------------------
679 filter_unqual :: GlobalRdrEnv -> AvailInfo -> Maybe AvailInfo
680 -- Filter the Avail by what's in scope unqualified
681 filter_unqual env (Avail n)
682 | in_scope env n = Just (Avail n)
683 | otherwise = Nothing
684 filter_unqual env (AvailTC n ns)
685 | not (null ns') = Just (AvailTC n ns')
686 | otherwise = Nothing
688 ns' = filter (in_scope env) ns
690 in_scope :: GlobalRdrEnv -> Name -> Bool
691 -- Checks whether the Name is in scope unqualified,
692 -- regardless of whether it's ambiguous or not
693 in_scope env n = any unQualOK (lookupGRE_Name env n)
695 -------------------------------
696 checkForDodgyExport :: IE RdrName -> AvailInfo -> RnM ()
697 checkForDodgyExport (IEThingAll tc) (AvailTC _ [n]) = addWarn (dodgyExportWarn tc)
698 -- This occurs when you import T(..), but
699 -- only export T abstractly. The single [n]
700 -- in the AvailTC is the type or class itself
701 checkForDodgyExport _ _ = return ()
703 -------------------------------
704 check_occs :: IE RdrName -> ExportOccMap -> AvailInfo -> RnM ExportOccMap
705 check_occs ie occs avail
706 = foldlM check occs (availNames avail)
709 = case lookupFM occs name_occ of
710 Nothing -> returnM (addToFM occs name_occ (name, ie))
713 | name == name' -- Duplicate export
714 -> do { warn_dup_exports <- doptM Opt_WarnDuplicateExports ;
715 warnIf warn_dup_exports (dupExportWarn name_occ ie ie') ;
718 | otherwise -- Same occ name but different names: an error
719 -> do { global_env <- getGlobalRdrEnv ;
720 addErr (exportClashErr global_env name name' ie ie') ;
723 name_occ = nameOccName name
726 %*********************************************************
728 \subsection{Unused names}
730 %*********************************************************
733 reportUnusedNames :: TcGblEnv -> RnM ()
734 reportUnusedNames gbl_env
735 = warnUnusedModules unused_imp_mods `thenM_`
736 warnUnusedTopBinds bad_locals `thenM_`
737 warnUnusedImports bad_imports `thenM_`
738 printMinimalImports minimal_imports
740 used_names, all_used_names :: NameSet
741 used_names = findUses (tcg_dus gbl_env) emptyNameSet
742 all_used_names = used_names `unionNameSets`
743 mkNameSet (mapCatMaybes nameParent_maybe (nameSetToList used_names))
744 -- A use of C implies a use of T,
745 -- if C was brought into scope by T(..) or T(C)
747 -- Collect the defined names from the in-scope environment
748 defined_names :: [GlobalRdrElt]
749 defined_names = globalRdrEnvElts (tcg_rdr_env gbl_env)
751 defined_and_used, defined_but_not_used :: [GlobalRdrElt]
752 (defined_and_used, defined_but_not_used) = partition is_used defined_names
754 is_used gre = gre_name gre `elemNameSet` all_used_names
756 -- Filter out the ones that are
757 -- (a) defined in this module, and
758 -- (b) not defined by a 'deriving' clause
759 -- The latter have an Internal Name, so we can filter them out easily
760 bad_locals :: [GlobalRdrElt]
761 bad_locals = filter is_bad defined_but_not_used
762 is_bad :: GlobalRdrElt -> Bool
763 is_bad gre = isLocalGRE gre && isExternalName (gre_name gre)
765 bad_imports :: [GlobalRdrElt]
766 bad_imports = filter bad_imp defined_but_not_used
767 bad_imp (GRE {gre_prov = Imported imp_specs True})
768 = not (all (module_unused . is_mod) imp_specs)
769 -- Don't complain about unused imports if we've already said the
770 -- entire import is unused
771 bad_imp other = False
773 -- To figure out the minimal set of imports, start with the things
774 -- that are in scope (i.e. in gbl_env). Then just combine them
775 -- into a bunch of avails, so they are properly grouped
776 minimal_imports :: FiniteMap ModuleName AvailEnv
777 minimal_imports0 = emptyFM
778 minimal_imports1 = foldr add_name minimal_imports0 defined_and_used
779 minimal_imports = foldr add_inst_mod minimal_imports1 direct_import_mods
780 -- The last line makes sure that we retain all direct imports
781 -- even if we import nothing explicitly.
782 -- It's not necessarily redundant to import such modules. Consider
786 -- The import M() is not *necessarily* redundant, even if
787 -- we suck in no instance decls from M (e.g. it contains
788 -- no instance decls, or This contains no code). It may be
789 -- that we import M solely to ensure that M's orphan instance
790 -- decls (or those in its imports) are visible to people who
791 -- import This. Sigh.
792 -- There's really no good way to detect this, so the error message
793 -- in RnEnv.warnUnusedModules is weakened instead
796 -- We've carefully preserved the provenance so that we can
797 -- construct minimal imports that import the name by (one of)
798 -- the same route(s) as the programmer originally did.
799 add_name (GRE {gre_name = n,
800 gre_prov = Imported imp_specs _}) acc
801 = addToFM_C plusAvailEnv acc (is_mod (head imp_specs))
802 (unitAvailEnv (mk_avail n (nameParent_maybe n)))
806 -- n is the name of the thing, p is the name of its parent
807 mk_avail n (Just p) = AvailTC p [p,n]
808 mk_avail n Nothing | isTcOcc (nameOccName n) = AvailTC n [n]
809 | otherwise = Avail n
812 | m `elemFM` acc = acc -- We import something already
813 | otherwise = addToFM acc m emptyAvailEnv
814 -- Add an empty collection of imports for a module
815 -- from which we have sucked only instance decls
817 imports = tcg_imports gbl_env
819 direct_import_mods :: [ModuleName]
820 direct_import_mods = map (moduleName . fst)
821 (moduleEnvElts (imp_mods imports))
823 hasEmptyImpList :: ModuleName -> Bool
825 case lookupModuleEnvByName (imp_mods imports) m of
826 Just (_,Just x) -> not x
829 -- unused_imp_mods are the directly-imported modules
830 -- that are not mentioned in minimal_imports1
831 -- [Note: not 'minimal_imports', because that includes directly-imported
832 -- modules even if we use nothing from them; see notes above]
833 unused_imp_mods = [m | m <- direct_import_mods,
834 isNothing (lookupFM minimal_imports1 m),
836 not (hasEmptyImpList m)]
837 -- hasEmptyImpList arranges not to complain about
838 -- import M (), which is an idiom for importing
839 -- instance declarations
841 module_unused :: ModuleName -> Bool
842 module_unused mod = mod `elem` unused_imp_mods
845 -- ToDo: deal with original imports with 'qualified' and 'as M' clauses
846 printMinimalImports :: FiniteMap ModuleName AvailEnv -- Minimal imports
848 printMinimalImports imps
849 = ifOptM Opt_D_dump_minimal_imports $ do {
851 mod_ies <- mappM to_ies (fmToList imps) ;
852 this_mod <- getModule ;
853 rdr_env <- getGlobalRdrEnv ;
854 ioToTcRn (do { h <- openFile (mkFilename this_mod) WriteMode ;
855 printForUser h (unQualInScope rdr_env)
856 (vcat (map ppr_mod_ie mod_ies)) })
859 mkFilename this_mod = moduleNameUserString (moduleName this_mod) ++ ".imports"
860 ppr_mod_ie (mod_name, ies)
861 | mod_name == pRELUDE_Name
863 | null ies -- Nothing except instances comes from here
864 = ptext SLIT("import") <+> ppr mod_name <> ptext SLIT("() -- Instances only")
866 = ptext SLIT("import") <+> ppr mod_name <>
867 parens (fsep (punctuate comma (map ppr ies)))
869 to_ies (mod, avail_env) = mappM to_ie (availEnvElts avail_env) `thenM` \ ies ->
872 to_ie :: AvailInfo -> RnM (IE Name)
873 -- The main trick here is that if we're importing all the constructors
874 -- we want to say "T(..)", but if we're importing only a subset we want
875 -- to say "T(A,B,C)". So we have to find out what the module exports.
876 to_ie (Avail n) = returnM (IEVar n)
877 to_ie (AvailTC n [m]) = ASSERT( n==m )
878 returnM (IEThingAbs n)
880 = loadSrcInterface doc n_mod False `thenM` \ iface ->
881 case [xs | (m,as) <- mi_exports iface,
884 x == nameOccName n] of
885 [xs] | all_used xs -> returnM (IEThingAll n)
886 | otherwise -> returnM (IEThingWith n (filter (/= n) ns))
887 other -> pprTrace "to_ie" (ppr n <+> ppr n_mod <+> ppr other) $
890 all_used avail_occs = all (`elem` map nameOccName ns) avail_occs
891 doc = text "Compute minimal imports from" <+> ppr n
892 n_mod = nameModuleName n
896 %************************************************************************
900 %************************************************************************
903 badImportItemErr mod from ie
904 = sep [ptext SLIT("Module"), quotes (ppr mod), source_import,
905 ptext SLIT("does not export"), quotes (ppr ie)]
907 source_import = case from of
908 True -> ptext SLIT("(hi-boot interface)")
911 dodgyImportWarn mod item = dodgyMsg (ptext SLIT("import")) item
912 dodgyExportWarn item = dodgyMsg (ptext SLIT("export")) item
915 = sep [ ptext SLIT("The") <+> kind <+> ptext SLIT("item") <+> quotes (ppr (IEThingAll tc)),
916 ptext SLIT("suggests that") <+> quotes (ppr tc) <+> ptext SLIT("has constructor or class methods"),
917 ptext SLIT("but it has none; it is a type synonym or abstract type or class") ]
920 = hsep [ ptext SLIT("Unknown module in export list: module"), quotes (ppr mod)]
922 exportItemErr export_item
923 = sep [ ptext SLIT("The export item") <+> quotes (ppr export_item),
924 ptext SLIT("attempts to export constructors or class methods that are not visible here") ]
926 exportClashErr global_env name1 name2 ie1 ie2
927 = vcat [ ptext SLIT("Conflicting exports for") <+> quotes (ppr occ) <> colon
928 , ppr_export ie1 name1
929 , ppr_export ie2 name2 ]
931 occ = nameOccName name1
932 ppr_export ie name = nest 2 (quotes (ppr ie) <+> ptext SLIT("exports") <+>
933 quotes (ppr name) <+> pprNameProvenance (get_gre name))
935 -- get_gre finds a GRE for the Name, so that we can show its provenance
937 = case lookupGRE_Name global_env name of
939 [] -> pprPanic "exportClashErr" (ppr name)
942 = vcat [ptext SLIT("Multiple declarations of") <+> quotes (ppr n),
943 nest 4 (vcat (map ppr sorted_locs))]
945 sorted_locs = sortLt occ'ed_before (map nameSrcLoc (n:ns))
946 occ'ed_before a b = LT == compare a b
948 dupExportWarn occ_name ie1 ie2
949 = hsep [quotes (ppr occ_name),
950 ptext SLIT("is exported by"), quotes (ppr ie1),
951 ptext SLIT("and"), quotes (ppr ie2)]
954 = hsep [ptext SLIT("Duplicate"),
955 quotes (ptext SLIT("Module") <+> ppr mod),
956 ptext SLIT("in export list")]
959 = sep [ ptext SLIT("Module") <+> quotes (ppr mod) <+> ptext SLIT("is deprecated:"),