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
12 #include "HsVersions.h"
14 import {-# SOURCE #-} RnHiFiles ( loadInterface )
16 import CmdLineOpts ( DynFlag(..) )
18 import HsSyn ( IE(..), ieName, ImportDecl(..),
19 ForeignDecl(..), HsGroup(..),
20 collectLocatedHsBinders, tyClDeclNames
22 import RdrHsSyn ( RdrNameIE, RdrNameImportDecl, main_RDR_Unqual )
27 import PrelNames ( pRELUDE_Name, isBuiltInSyntaxName )
28 import Module ( Module, ModuleName, ModuleEnv, moduleName,
29 moduleNameUserString, isHomeModule,
30 emptyModuleEnv, unitModuleEnvByName, unitModuleEnv,
31 lookupModuleEnvByName, extendModuleEnvByName, moduleEnvElts )
32 import Name ( Name, nameSrcLoc, nameOccName, nameModule, isExternalName )
35 import OccName ( OccName, srcDataName, isTcOcc )
36 import HscTypes ( Provenance(..), ImportReason(..), GlobalRdrEnv,
37 GenAvailInfo(..), AvailInfo, Avails, GhciMode(..),
39 availName, availNames, availsToNameSet,
40 Deprecations(..), ModIface(..), Dependencies(..),
41 GlobalRdrElt(..), unQualInScope, isLocalGRE, pprNameProvenance
43 import RdrName ( RdrName, rdrNameOcc, setRdrNameSpace, lookupRdrEnv, rdrEnvToList,
44 emptyRdrEnv, foldRdrEnv, rdrEnvElts, mkRdrUnqual, isQual )
46 import Maybe ( isJust, isNothing, catMaybes )
47 import Maybes ( orElse )
48 import ListSetOps ( removeDups )
49 import Util ( sortLt, notNull )
50 import List ( partition, insert )
51 import IO ( openFile, IOMode(..) )
56 %************************************************************************
60 %************************************************************************
63 rnImports :: [RdrNameImportDecl]
64 -> TcRn m (GlobalRdrEnv, ImportAvails)
67 = -- PROCESS IMPORT DECLS
68 -- Do the non {- SOURCE -} ones first, so that we get a helpful
69 -- warning for {- SOURCE -} ones that are unnecessary
70 getModule `thenM` \ this_mod ->
71 getSrcLocM `thenM` \ loc ->
72 doptM Opt_NoImplicitPrelude `thenM` \ opt_no_prelude ->
74 all_imports = mk_prel_imports this_mod loc opt_no_prelude ++ imports
75 (source, ordinary) = partition is_source_import all_imports
76 is_source_import (ImportDecl _ is_boot _ _ _ _) = is_boot
78 get_imports = importsFromImportDecl this_mod
80 mappM get_imports ordinary `thenM` \ stuff1 ->
81 mappM get_imports source `thenM` \ stuff2 ->
85 (imp_gbl_envs, imp_avails) = unzip (stuff1 ++ stuff2)
86 gbl_env :: GlobalRdrEnv
87 gbl_env = foldr plusGlobalRdrEnv emptyRdrEnv imp_gbl_envs
89 all_avails :: ImportAvails
90 all_avails = foldr plusImportAvails emptyImportAvails imp_avails
93 returnM (gbl_env, all_avails)
95 -- NB: opt_NoImplicitPrelude is slightly different to import Prelude ();
96 -- because the former doesn't even look at Prelude.hi for instance
97 -- declarations, whereas the latter does.
98 mk_prel_imports this_mod loc no_prelude
99 | moduleName this_mod == pRELUDE_Name
100 || explicit_prelude_import
104 | otherwise = [preludeImportDecl loc]
106 explicit_prelude_import
107 = notNull [ () | (ImportDecl mod _ _ _ _ _) <- imports,
108 mod == pRELUDE_Name ]
110 preludeImportDecl loc
111 = ImportDecl pRELUDE_Name
112 False {- Not a boot interface -}
113 False {- Not qualified -}
114 Nothing {- No "as" -}
115 Nothing {- No import list -}
120 importsFromImportDecl :: Module
122 -> TcRn m (GlobalRdrEnv, ImportAvails)
124 importsFromImportDecl this_mod
125 (ImportDecl imp_mod_name is_boot qual_only as_mod imp_spec iloc)
128 doc = ppr imp_mod_name <+> ptext SLIT("is directly imported")
131 -- If there's an error in loadInterface, (e.g. interface
132 -- file not found) we get lots of spurious errors from 'filterImports'
133 tryM (loadInterface doc imp_mod_name (ImportByUser is_boot)) `thenM` \ mb_iface ->
136 Left exn -> returnM (emptyRdrEnv, emptyImportAvails ) ;
140 imp_mod = mi_module iface
141 avails_by_module = mi_exports iface
142 deprecs = mi_deprecs iface
143 is_orph = mi_orphan iface
147 avails = [ avail | (mod_name, avails) <- avails_by_module,
148 mod_name /= this_mod_name,
150 this_mod_name = moduleName this_mod
151 -- If the module exports anything defined in this module, just ignore it.
152 -- Reason: otherwise it looks as if there are two local definition sites
153 -- for the thing, and an error gets reported. Easiest thing is just to
154 -- filter them out up front. This situation only arises if a module
155 -- imports itself, or another module that imported it. (Necessarily,
156 -- this invoves a loop.)
158 -- Tiresome consequence: if you say
163 -- module B( AType ) where
164 -- import {-# SOURCE #-} A( AType )
166 -- then you'll get a 'B does not export AType' message. Oh well.
169 -- Filter the imports according to the import list
170 filterImports imp_mod is_boot imp_spec avails `thenM` \ (filtered_avails, explicits) ->
173 -- Compute new transitive dependencies
174 orphans | is_orph = insert imp_mod_name (dep_orphs deps)
175 | otherwise = dep_orphs deps
177 (dependent_mods, dependent_pkgs)
178 | isHomeModule imp_mod
179 = -- Imported module is from the home package
180 -- Take its dependent modules and
181 -- (a) remove this_mod (might be there as a hi-boot)
182 -- (b) add imp_mod itself
183 -- Take its dependent packages unchanged
184 ((imp_mod_name, is_boot) : filter not_self (dep_mods deps), dep_pkgs deps)
187 = -- Imported module is from another package
188 -- Dump the dependent modules
189 -- Add the package imp_mod comes from to the dependent packages
191 ([], insert (mi_package iface) (dep_pkgs deps))
193 not_self (m, _) = m /= this_mod_name
195 import_all = case imp_spec of
196 (Just (False, _)) -> False -- Imports are spec'd explicitly
197 other -> True -- Everything is imported,
198 -- (or almost everything [hiding])
200 qual_mod_name = case as_mod of
201 Nothing -> imp_mod_name
202 Just another_name -> another_name
204 -- unqual_avails is the Avails that are visible in *unqualified* form
205 -- We need to know this so we know what to export when we see
206 -- module M ( module P ) where ...
207 -- Then we must export whatever came from P unqualified.
208 avail_env = mkAvailEnv filtered_avails
210 mk_prov name = NonLocalDef (UserImport imp_mod iloc (name `elemNameSet` explicits))
211 gbl_env = mkGlobalRdrEnv qual_mod_name (not qual_only)
212 mk_prov filtered_avails deprecs
213 imports = ImportAvails {
214 imp_qual = unitModuleEnvByName qual_mod_name avail_env,
216 imp_mods = unitModuleEnv imp_mod (imp_mod, import_all),
218 imp_dep_mods = mkModDeps dependent_mods,
219 imp_dep_pkgs = dependent_pkgs }
222 -- Complain if we import a deprecated module
223 ifOptM Opt_WarnDeprecations (
225 DeprecAll txt -> addWarn (moduleDeprec imp_mod_name txt)
229 returnM (gbl_env, imports)
232 mkModDeps :: [(ModuleName, IsBootInterface)]
233 -> ModuleEnv (ModuleName, IsBootInterface)
234 mkModDeps deps = foldl add emptyModuleEnv deps
236 add env elt@(m,_) = extendModuleEnvByName env m elt
240 %************************************************************************
242 importsFromLocalDecls
244 %************************************************************************
246 From the top-level declarations of this module produce
247 * the lexical environment
249 created by its bindings.
251 Complain about duplicate bindings
254 importsFromLocalDecls :: HsGroup RdrName
255 -> TcRn m (GlobalRdrEnv, ImportAvails)
256 importsFromLocalDecls group
257 = getModule `thenM` \ this_mod ->
258 getLocalDeclBinders this_mod group `thenM` \ avails ->
259 -- The avails that are returned don't include the "system" names
261 all_names :: [Name] -- All the defns; no dups eliminated
262 all_names = [name | avail <- avails, name <- availNames avail]
265 (_, dups) = removeDups compare all_names
267 -- Check for duplicate definitions
268 -- The complaint will come out as "Multiple declarations of Foo.f" because
269 -- since 'f' is in the env twice, the unQualInScope used by the error-msg
270 -- printer returns False. It seems awkward to fix, unfortunately.
271 mappM_ (addErr . dupDeclErr) dups `thenM_`
273 doptM Opt_NoImplicitPrelude `thenM` \ implicit_prelude ->
275 mod_name = moduleName this_mod
276 mk_prov n = LocalDef -- Provenance is local
278 unqual_imp = True -- Want unqualified names in scope
279 gbl_env = mkGlobalRdrEnv mod_name unqual_imp mk_prov avails NoDeprecs
280 -- NoDeprecs: don't complain about locally defined names
281 -- For a start, we may be exporting a deprecated thing
282 -- Also we may use a deprecated thing in the defn of another
283 -- deprecated things. We may even use a deprecated thing in
284 -- the defn of a non-deprecated thing, when changing a module's
288 -- Optimisation: filter out names for built-in syntax
289 -- They just clutter up the environment (esp tuples), and the parser
290 -- will generate Exact RdrNames for them, so the cluttered
291 -- envt is no use. To avoid doing this filter all the time,
292 -- we use -fno-implicit-prelude as a clue that the filter is
293 -- worth while. Really, it's only useful for GHC.Base and GHC.Tuple.
295 -- It's worth doing because it makes the environment smaller for
296 -- every module that imports the Prelude
298 -- Note: don't filter the gbl_env (hence avails, not avails' in
299 -- defn of gbl_env above). Stupid reason: when parsing
300 -- data type decls, the constructors start as Exact tycon-names,
301 -- and then get turned into data con names by zapping the name space;
302 -- but that stops them being Exact, so they get looked up. Sigh.
303 -- It doesn't matter because it only affects the Data.Tuple really.
304 -- The important thing is to trim down the exports.
306 avails' | implicit_prelude = filter not_built_in_syntax avails
308 not_built_in_syntax a = not (all isBuiltInSyntaxName (availNames a))
309 -- Only filter it if all the names of the avail are built-in
310 -- In particular, lists have (:) which is not built in syntax
311 -- so we don't filter it out.
313 avail_env = mkAvailEnv avails'
314 imports = emptyImportAvails {
315 imp_qual = unitModuleEnv this_mod avail_env,
319 returnM (gbl_env, imports)
323 %*********************************************************
325 \subsection{Getting binders out of a declaration}
327 %*********************************************************
329 @getLocalDeclBinders@ returns the names for a @RdrNameHsDecl@. It's
330 used for both source code (from @importsFromLocalDecls@) and interface
331 files (@loadDecl@ calls @getTyClDeclBinders@).
333 *** See "THE NAMING STORY" in HsDecls ****
336 getLocalDeclBinders :: Module -> HsGroup RdrName -> TcRn m [AvailInfo]
337 getLocalDeclBinders mod (HsGroup {hs_valds = val_decls,
338 hs_tyclds = tycl_decls,
339 hs_fords = foreign_decls })
340 = -- For type and class decls, we generate Global names, with
341 -- no export indicator. They need to be global because they get
342 -- permanently bound into the TyCons and Classes. They don't need
343 -- an export indicator because they are all implicitly exported.
345 mappM new_tc tycl_decls `thenM` \ tc_avails ->
346 mappM new_bndr (for_hs_bndrs ++ val_hs_bndrs) `thenM` \ simple_bndrs ->
348 returnM (tc_avails ++ map Avail simple_bndrs)
350 new_bndr (rdr_name,loc) = newTopBinder mod rdr_name loc
352 val_hs_bndrs = collectLocatedHsBinders val_decls
353 for_hs_bndrs = [(nm,loc) | ForeignImport nm _ _ _ loc <- foreign_decls]
355 new_tc tc_decl = mappM new_bndr (tyClDeclNames tc_decl) `thenM` \ names@(main_name:_) ->
356 returnM (AvailTC main_name names)
360 %************************************************************************
362 \subsection{Filtering imports}
364 %************************************************************************
366 @filterImports@ takes the @ExportEnv@ telling what the imported module makes
367 available, and filters it through the import spec (if any).
370 filterImports :: Module -- The module being imported
371 -> IsBootInterface -- Tells whether it's a {-# SOURCE #-} import
372 -> Maybe (Bool, [RdrNameIE]) -- Import spec; True => hiding
373 -> [AvailInfo] -- What's available
374 -> TcRn m ([AvailInfo], -- What's imported
375 NameSet) -- What was imported explicitly
377 -- Complains if import spec mentions things that the module doesn't export
378 -- Warns/informs if import spec contains duplicates.
379 filterImports mod from Nothing imports
380 = returnM (imports, emptyNameSet)
382 filterImports mod from (Just (want_hiding, import_items)) total_avails
383 = mappM get_item import_items `thenM` \ avails_w_explicits_s ->
385 (item_avails, explicits_s) = unzip (concat avails_w_explicits_s)
386 explicits = foldl addListToNameSet emptyNameSet explicits_s
389 let -- All imported; item_avails to be hidden
390 hidden = availsToNameSet item_avails
391 keep n = not (n `elemNameSet` hidden)
393 returnM (pruneAvails keep total_avails, emptyNameSet)
395 -- Just item_avails imported; nothing to be hidden
396 returnM (item_avails, explicits)
398 import_fm :: FiniteMap OccName AvailInfo
399 import_fm = listToFM [ (nameOccName name, avail)
400 | avail <- total_avails,
401 name <- availNames avail]
402 -- Even though availNames returns data constructors too,
403 -- they won't make any difference because naked entities like T
404 -- in an import list map to TcOccs, not VarOccs.
406 bale_out item = addErr (badImportItemErr mod from item) `thenM_`
409 get_item :: RdrNameIE -> TcRn m [(AvailInfo, [Name])]
410 -- Empty list for a bad item.
411 -- Singleton is typical case.
412 -- Can have two when we are hiding, and mention C which might be
413 -- both a class and a data constructor.
414 -- The [Name] is the list of explicitly-mentioned names
415 get_item item@(IEModuleContents _) = bale_out item
417 get_item item@(IEThingAll _)
418 = case check_item item of
419 Nothing -> bale_out item
420 Just avail@(AvailTC _ [n]) -> -- This occurs when you import T(..), but
421 -- only export T abstractly. The single [n]
422 -- in the AvailTC is the type or class itself
423 ifOptM Opt_WarnMisc (addWarn (dodgyImportWarn mod item)) `thenM_`
424 returnM [(avail, [availName avail])]
425 Just avail -> returnM [(avail, [availName avail])]
427 get_item item@(IEThingAbs n)
428 | want_hiding -- hiding( C )
429 -- Here the 'C' can be a data constructor *or* a type/class
430 = case catMaybes [check_item item, check_item (IEVar data_n)] of
432 avails -> returnM [(a, []) | a <- avails]
433 -- The 'explicits' list is irrelevant when hiding
435 data_n = setRdrNameSpace n srcDataName
438 = case check_item item of
439 Nothing -> bale_out item
440 Just avail -> returnM [(avail, availNames avail)]
443 | isNothing maybe_in_import_avails ||
444 isNothing maybe_filtered_avail
448 = Just filtered_avail
451 wanted_occ = rdrNameOcc (ieName item)
452 maybe_in_import_avails = lookupFM import_fm wanted_occ
454 Just avail = maybe_in_import_avails
455 maybe_filtered_avail = filterAvail item avail
456 Just filtered_avail = maybe_filtered_avail
460 filterAvail :: RdrNameIE -- Wanted
461 -> AvailInfo -- Available
462 -> Maybe AvailInfo -- Resulting available;
463 -- Nothing if (any of the) wanted stuff isn't there
465 filterAvail ie@(IEThingWith want wants) avail@(AvailTC n ns)
466 | sub_names_ok = Just (AvailTC n (filter is_wanted ns))
467 | otherwise = Nothing
469 is_wanted name = nameOccName name `elem` wanted_occs
470 sub_names_ok = all (`elem` avail_occs) wanted_occs
471 avail_occs = map nameOccName ns
472 wanted_occs = map rdrNameOcc (want:wants)
474 filterAvail (IEThingAbs _) (AvailTC n ns) = ASSERT( n `elem` ns )
477 filterAvail (IEThingAbs _) avail@(Avail n) = Just avail -- Type synonyms
479 filterAvail (IEVar _) avail@(Avail n) = Just avail
480 filterAvail (IEVar v) avail@(AvailTC n ns) = Just (AvailTC n (filter wanted ns))
482 wanted n = nameOccName n == occ
484 -- The second equation happens if we import a class op, thus
486 -- where op is a class operation
488 filterAvail (IEThingAll _) avail@(AvailTC _ _) = Just avail
489 -- We don't complain even if the IE says T(..), but
490 -- no constrs/class ops of T are available
491 -- Instead that's caught with a warning by the caller
493 filterAvail ie avail = Nothing
497 %************************************************************************
499 \subsection{Export list processing}
501 %************************************************************************
503 Processing the export list.
505 You might think that we should record things that appear in the export
506 list as ``occurrences'' (using @addOccurrenceName@), but you'd be
507 wrong. We do check (here) that they are in scope, but there is no
508 need to slurp in their actual declaration (which is what
509 @addOccurrenceName@ forces).
511 Indeed, doing so would big trouble when compiling @PrelBase@, because
512 it re-exports @GHC@, which includes @takeMVar#@, whose type includes
513 @ConcBase.StateAndSynchVar#@, and so on...
516 type ExportAccum -- The type of the accumulating parameter of
517 -- the main worker function in exportsFromAvail
518 = ([ModuleName], -- 'module M's seen so far
519 ExportOccMap, -- Tracks exported occurrence names
520 AvailEnv) -- The accumulated exported stuff, kept in an env
521 -- so we can common-up related AvailInfos
522 emptyExportAccum = ([], emptyFM, emptyAvailEnv)
524 type ExportOccMap = FiniteMap OccName (Name, RdrNameIE)
525 -- Tracks what a particular exported OccName
526 -- in an export list refers to, and which item
527 -- it came from. It's illegal to export two distinct things
528 -- that have the same occurrence name
531 exportsFromAvail :: Maybe Module -- Nothing => no 'module M(..) where' header at all
532 -> Maybe [RdrNameIE] -- Nothing => no explicit export list
534 -- Complains if two distinct exports have same OccName
535 -- Warns about identical exports.
536 -- Complains about exports items not in scope
538 exportsFromAvail maybe_mod exports
539 = do { TcGblEnv { tcg_rdr_env = rdr_env,
540 tcg_imports = imports } <- getGblEnv ;
542 -- If the module header is omitted altogether, then behave
543 -- as if the user had written "module Main(main) where..."
544 -- EXCEPT in interactive mode, when we behave as if he had
545 -- written "module Main where ..."
546 -- Reason: don't want to complain about 'main' not in scope
547 -- in interactive mode
548 ghci_mode <- getGhciMode ;
552 Nothing | ghci_mode == Interactive -> Nothing
553 | otherwise -> Just [IEVar main_RDR_Unqual] } ;
555 exports_from_avail exports rdr_env imports }
557 exports_from_avail Nothing rdr_env
558 imports@(ImportAvails { imp_env = entity_avail_env })
559 = -- Export all locally-defined things
560 -- We do this by filtering the global RdrEnv,
561 -- keeping only things that are (a) qualified,
562 -- (b) locally defined, (c) a 'main' name
563 -- Then we look up in the entity-avail-env
564 return [ lookupAvailEnv entity_avail_env name
565 | (rdr_name, gres) <- rdrEnvToList rdr_env,
566 isQual rdr_name, -- Avoid duplicates
567 GRE { gre_name = name,
568 gre_parent = Nothing, -- Main things only
569 gre_prov = LocalDef } <- gres
572 exports_from_avail (Just export_items) rdr_env
573 (ImportAvails { imp_qual = mod_avail_env,
574 imp_env = entity_avail_env })
575 = foldlM exports_from_item emptyExportAccum
576 export_items `thenM` \ (_, _, export_avail_map) ->
577 returnM (nameEnvElts export_avail_map)
580 exports_from_item :: ExportAccum -> RdrNameIE -> TcRn m ExportAccum
582 exports_from_item acc@(mods, occs, avails) ie@(IEModuleContents mod)
583 | mod `elem` mods -- Duplicate export of M
584 = do { warn_dup_exports <- doptM Opt_WarnDuplicateExports ;
585 warnIf warn_dup_exports (dupModuleExport mod) ;
589 = case lookupModuleEnvByName mod_avail_env mod of
590 Nothing -> addErr (modExportErr mod) `thenM_`
595 mod_avails = [ filtered_avail
596 | avail <- availEnvElts avail_env,
597 let mb_avail = filter_unqual rdr_env avail,
599 let Just filtered_avail = mb_avail]
601 avails' = foldl addAvail avails mod_avails
603 -- This check_occs not only finds conflicts between this item
604 -- and others, but also internally within this item. That is,
605 -- if 'M.x' is in scope in several ways, we'll have several
606 -- members of mod_avails with the same OccName.
608 foldlM (check_occs ie) occs mod_avails `thenM` \ occs' ->
609 returnM (mod:mods, occs', avails')
611 exports_from_item acc@(mods, occs, avails) ie
612 = lookupGRE (ieName ie) `thenM` \ mb_gre ->
614 Nothing -> addErr (unknownNameErr (ieName ie)) `thenM_`
618 -- Get the AvailInfo for the parent of the specified name
620 parent = gre_parent gre `orElse` gre_name gre
621 avail = lookupAvailEnv entity_avail_env parent
623 -- Filter out the bits we want
624 case filterAvail ie avail of {
625 Nothing -> -- Not enough availability
626 addErr (exportItemErr ie) `thenM_`
631 -- Phew! It's OK! Now to check the occurrence stuff!
632 warnIf (not (ok_item ie avail)) (dodgyExportWarn ie) `thenM_`
633 check_occs ie occs export_avail `thenM` \ occs' ->
634 returnM (mods, occs', addAvail avails export_avail)
638 -------------------------------
639 filter_unqual :: GlobalRdrEnv -> AvailInfo -> Maybe AvailInfo
640 -- Filter the Avail by what's in scope unqualified
641 filter_unqual env (Avail n)
642 | in_scope env n = Just (Avail n)
643 | otherwise = Nothing
644 filter_unqual env (AvailTC n ns)
645 | not (null ns') = Just (AvailTC n ns')
646 | otherwise = Nothing
648 ns' = filter (in_scope env) ns
650 in_scope :: GlobalRdrEnv -> Name -> Bool
651 -- Checks whether the Name is in scope unqualified,
652 -- regardless of whether it's ambiguous or not
654 = case lookupRdrEnv env (mkRdrUnqual (nameOccName n)) of
656 Just gres -> or [n == gre_name g | g <- gres]
659 -------------------------------
660 ok_item (IEThingAll _) (AvailTC _ [n]) = False
661 -- This occurs when you import T(..), but
662 -- only export T abstractly. The single [n]
663 -- in the AvailTC is the type or class itself
666 -------------------------------
667 check_occs :: RdrNameIE -> ExportOccMap -> AvailInfo -> TcRn m ExportOccMap
668 check_occs ie occs avail
669 = foldlM check occs (availNames avail)
672 = case lookupFM occs name_occ of
673 Nothing -> returnM (addToFM occs name_occ (name, ie))
676 | name == name' -- Duplicate export
677 -> do { warn_dup_exports <- doptM Opt_WarnDuplicateExports ;
678 warnIf warn_dup_exports (dupExportWarn name_occ ie ie') ;
681 | otherwise -- Same occ name but different names: an error
682 -> do { global_env <- getGlobalRdrEnv ;
683 addErr (exportClashErr global_env name name' ie ie') ;
686 name_occ = nameOccName name
689 %*********************************************************
691 \subsection{Unused names}
693 %*********************************************************
696 reportUnusedNames :: TcGblEnv -> DefUses -> TcRn m ()
697 reportUnusedNames gbl_env dus
698 = warnUnusedModules unused_imp_mods `thenM_`
699 warnUnusedTopBinds bad_locals `thenM_`
700 warnUnusedImports bad_imports `thenM_`
701 printMinimalImports minimal_imports
703 used_names :: NameSet
704 used_names = findUses dus emptyNameSet
706 -- Collect the defined names from the in-scope environment
707 -- Look for the qualified ones only, else get duplicates
708 defined_names :: [GlobalRdrElt]
709 defined_names = foldRdrEnv add [] (tcg_rdr_env gbl_env)
710 add rdr_name ns acc | isQual rdr_name = ns ++ acc
713 defined_and_used, defined_but_not_used :: [GlobalRdrElt]
714 (defined_and_used, defined_but_not_used) = partition is_used defined_names
716 is_used gre = n `elemNameSet` used_names || any (`elemNameSet` used_names) kids
717 -- The 'kids' part is because a use of C implies a use of T,
718 -- if C was brought into scope by T(..) or T(C)
721 kids = case lookupAvailEnv_maybe avail_env n of
722 Just (AvailTC n ns) -> ns
723 other -> [] -- Ids, class ops and datacons
724 -- (The latter two give Nothing)
726 -- Filter out the ones that are
727 -- (a) defined in this module, and
728 -- (b) not defined by a 'deriving' clause
729 -- The latter have an Internal Name, so we can filter them out easily
730 bad_locals :: [GlobalRdrElt]
731 bad_locals = filter is_bad defined_but_not_used
732 is_bad :: GlobalRdrElt -> Bool
733 is_bad gre = isLocalGRE gre && isExternalName (gre_name gre)
735 bad_imports :: [GlobalRdrElt]
736 bad_imports = filter bad_imp defined_but_not_used
737 bad_imp (GRE {gre_prov = NonLocalDef (UserImport mod _ True)}) = not (module_unused mod)
738 bad_imp other = False
740 -- To figure out the minimal set of imports, start with the things
741 -- that are in scope (i.e. in gbl_env). Then just combine them
742 -- into a bunch of avails, so they are properly grouped
743 minimal_imports :: FiniteMap ModuleName AvailEnv
744 minimal_imports0 = emptyFM
745 minimal_imports1 = foldr add_name minimal_imports0 defined_and_used
746 minimal_imports = foldr add_inst_mod minimal_imports1 direct_import_mods
747 -- The last line makes sure that we retain all direct imports
748 -- even if we import nothing explicitly.
749 -- It's not necessarily redundant to import such modules. Consider
753 -- The import M() is not *necessarily* redundant, even if
754 -- we suck in no instance decls from M (e.g. it contains
755 -- no instance decls, or This contains no code). It may be
756 -- that we import M solely to ensure that M's orphan instance
757 -- decls (or those in its imports) are visible to people who
758 -- import This. Sigh.
759 -- There's really no good way to detect this, so the error message
760 -- in RnEnv.warnUnusedModules is weakened instead
763 -- We've carefully preserved the provenance so that we can
764 -- construct minimal imports that import the name by (one of)
765 -- the same route(s) as the programmer originally did.
766 add_name (GRE {gre_name = n, gre_parent = p,
767 gre_prov = NonLocalDef (UserImport m _ _)}) acc
768 = addToFM_C plusAvailEnv acc (moduleName m)
769 (unitAvailEnv (mk_avail n p))
773 -- n is the name of the thing, p is the name of its parent
774 mk_avail n (Just p) = AvailTC p [p,n]
775 mk_avail n Nothing | isTcOcc (nameOccName n) = AvailTC n [n]
776 | otherwise = Avail n
779 | m `elemFM` acc = acc -- We import something already
780 | otherwise = addToFM acc m emptyAvailEnv
781 -- Add an empty collection of imports for a module
782 -- from which we have sucked only instance decls
784 imports = tcg_imports gbl_env
785 avail_env = imp_env imports
787 direct_import_mods :: [ModuleName]
788 direct_import_mods = map (moduleName . fst)
789 (moduleEnvElts (imp_mods imports))
791 -- unused_imp_mods are the directly-imported modules
792 -- that are not mentioned in minimal_imports1
793 -- [Note: not 'minimal_imports', because that includes direcly-imported
794 -- modules even if we use nothing from them; see notes above]
795 unused_imp_mods = [m | m <- direct_import_mods,
796 isNothing (lookupFM minimal_imports1 m),
799 module_unused :: Module -> Bool
800 module_unused mod = moduleName mod `elem` unused_imp_mods
803 -- ToDo: deal with original imports with 'qualified' and 'as M' clauses
804 printMinimalImports :: FiniteMap ModuleName AvailEnv -- Minimal imports
806 printMinimalImports imps
807 = ifOptM Opt_D_dump_minimal_imports $ do {
809 mod_ies <- mappM to_ies (fmToList imps) ;
810 this_mod <- getModule ;
811 rdr_env <- getGlobalRdrEnv ;
812 ioToTcRn (do { h <- openFile (mkFilename this_mod) WriteMode ;
813 printForUser h (unQualInScope rdr_env)
814 (vcat (map ppr_mod_ie mod_ies)) })
817 mkFilename this_mod = moduleNameUserString (moduleName this_mod) ++ ".imports"
818 ppr_mod_ie (mod_name, ies)
819 | mod_name == pRELUDE_Name
821 | null ies -- Nothing except instances comes from here
822 = ptext SLIT("import") <+> ppr mod_name <> ptext SLIT("() -- Instances only")
824 = ptext SLIT("import") <+> ppr mod_name <>
825 parens (fsep (punctuate comma (map ppr ies)))
827 to_ies (mod, avail_env) = mappM to_ie (availEnvElts avail_env) `thenM` \ ies ->
830 to_ie :: AvailInfo -> TcRn m (IE Name)
831 -- The main trick here is that if we're importing all the constructors
832 -- we want to say "T(..)", but if we're importing only a subset we want
833 -- to say "T(A,B,C)". So we have to find out what the module exports.
834 to_ie (Avail n) = returnM (IEVar n)
835 to_ie (AvailTC n [m]) = ASSERT( n==m )
836 returnM (IEThingAbs n)
838 = loadInterface (text "Compute minimal imports from" <+> ppr n_mod)
839 n_mod ImportBySystem `thenM` \ iface ->
840 case [xs | (m,as) <- mi_exports iface,
844 [xs] | all (`elem` ns) xs -> returnM (IEThingAll n)
845 | otherwise -> returnM (IEThingWith n (filter (/= n) ns))
846 other -> pprTrace "to_ie" (ppr n <+> ppr (nameModule n) <+> ppr other) $
849 n_mod = moduleName (nameModule n)
853 %************************************************************************
857 %************************************************************************
860 badImportItemErr mod from ie
861 = sep [ptext SLIT("Module"), quotes (ppr mod), source_import,
862 ptext SLIT("does not export"), quotes (ppr ie)]
864 source_import = case from of
865 True -> ptext SLIT("(hi-boot interface)")
868 dodgyImportWarn mod item = dodgyMsg (ptext SLIT("import")) item
869 dodgyExportWarn item = dodgyMsg (ptext SLIT("export")) item
871 dodgyMsg kind item@(IEThingAll tc)
872 = sep [ ptext SLIT("The") <+> kind <+> ptext SLIT("item") <+> quotes (ppr item),
873 ptext SLIT("suggests that") <+> quotes (ppr tc) <+> ptext SLIT("has constructor or class methods"),
874 ptext SLIT("but it has none; it is a type synonym or abstract type or class") ]
877 = hsep [ ptext SLIT("Unknown module in export list: module"), quotes (ppr mod)]
879 exportItemErr export_item
880 = sep [ ptext SLIT("The export item") <+> quotes (ppr export_item),
881 ptext SLIT("attempts to export constructors or class methods that are not visible here") ]
883 exportClashErr global_env name1 name2 ie1 ie2
884 = vcat [ ptext SLIT("Conflicting exports for") <+> quotes (ppr occ) <> colon
885 , ppr_export ie1 name1
886 , ppr_export ie2 name2 ]
888 occ = nameOccName name1
889 ppr_export ie name = nest 2 (quotes (ppr ie) <+> ptext SLIT("exports") <+>
890 quotes (ppr name) <+> pprNameProvenance (get_gre name))
892 -- get_gre finds a GRE for the Name, in a very inefficient way
893 -- There isn't a more efficient way to do it, because we don't necessarily
894 -- know the RdrName under which this Name is in scope. So we just
895 -- search linearly. Shouldn't matter because this only happens
896 -- in an error message.
898 = case [gre | gres <- rdrEnvElts global_env,
900 gre_name gre == name] of
902 [] -> pprPanic "exportClashErr" (ppr name)
905 = vcat [ptext SLIT("Multiple declarations of") <+> quotes (ppr n),
906 nest 4 (vcat (map ppr sorted_locs))]
908 sorted_locs = sortLt occ'ed_before (map nameSrcLoc (n:ns))
909 occ'ed_before a b = LT == compare a b
911 dupExportWarn occ_name ie1 ie2
912 = hsep [quotes (ppr occ_name),
913 ptext SLIT("is exported by"), quotes (ppr ie1),
914 ptext SLIT("and"), quotes (ppr ie2)]
917 = hsep [ptext SLIT("Duplicate"),
918 quotes (ptext SLIT("Module") <+> ppr mod),
919 ptext SLIT("in export list")]
922 = sep [ ptext SLIT("Module") <+> quotes (ppr mod) <+> ptext SLIT("is deprecated:"),