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, nameModule )
35 import OccName ( srcDataName, isTcOcc, occNameFlavour, OccEnv,
36 mkOccEnv, lookupOccEnv, emptyOccEnv, extendOccEnv )
37 import HscTypes ( GenAvailInfo(..), AvailInfo, Avails, GhciMode(..),
38 IfaceExport, HomePackageTable, PackageIfaceTable,
39 availName, availNames, availsToNameSet, unQualInScope,
40 Deprecs(..), ModIface(..), Dependencies(..), lookupIface,
41 ExternalPackageState(..)
43 import RdrName ( RdrName, rdrNameOcc, setRdrNameSpace,
44 GlobalRdrEnv, mkGlobalRdrEnv, GlobalRdrElt(..),
45 emptyGlobalRdrEnv, plusGlobalRdrEnv, globalRdrEnvElts,
46 unQualOK, lookupGRE_Name,
47 Provenance(..), ImportSpec(..),
48 isLocalGRE, pprNameProvenance )
50 import Maybes ( isJust, isNothing, catMaybes, mapCatMaybes, seqMaybe )
51 import SrcLoc ( noSrcLoc, Located(..), mkGeneralSrcSpan,
53 import BasicTypes ( DeprecTxt )
54 import ListSetOps ( removeDups )
55 import Util ( sortLt, notNull, isSingleton )
56 import List ( partition, insert )
57 import IO ( openFile, IOMode(..) )
62 %************************************************************************
66 %************************************************************************
69 rnImports :: [LImportDecl RdrName]
70 -> RnM (GlobalRdrEnv, ImportAvails)
73 = -- PROCESS IMPORT DECLS
74 -- Do the non {- SOURCE -} ones first, so that we get a helpful
75 -- warning for {- SOURCE -} ones that are unnecessary
76 getModule `thenM` \ this_mod ->
77 doptM Opt_NoImplicitPrelude `thenM` \ opt_no_prelude ->
79 all_imports = mk_prel_imports this_mod opt_no_prelude ++ imports
80 (source, ordinary) = partition is_source_import all_imports
81 is_source_import (L _ (ImportDecl _ is_boot _ _ _)) = is_boot
83 get_imports = importsFromImportDecl this_mod
85 mappM get_imports ordinary `thenM` \ stuff1 ->
86 mappM get_imports source `thenM` \ stuff2 ->
90 (imp_gbl_envs, imp_avails) = unzip (stuff1 ++ stuff2)
91 gbl_env :: GlobalRdrEnv
92 gbl_env = foldr plusGlobalRdrEnv emptyGlobalRdrEnv imp_gbl_envs
94 all_avails :: ImportAvails
95 all_avails = foldr plusImportAvails emptyImportAvails imp_avails
98 returnM (gbl_env, all_avails)
100 -- NB: opt_NoImplicitPrelude is slightly different to import Prelude ();
101 -- because the former doesn't even look at Prelude.hi for instance
102 -- declarations, whereas the latter does.
103 mk_prel_imports this_mod no_prelude
104 | moduleName this_mod == pRELUDE_Name
105 || explicit_prelude_import
109 | otherwise = [preludeImportDecl]
111 explicit_prelude_import
112 = notNull [ () | L _ (ImportDecl mod _ _ _ _) <- imports,
113 unLoc mod == pRELUDE_Name ]
117 ImportDecl (L loc pRELUDE_Name)
118 False {- Not a boot interface -}
119 False {- Not qualified -}
120 Nothing {- No "as" -}
121 Nothing {- No import list -}
123 loc = mkGeneralSrcSpan FSLIT("Implicit import declaration")
127 importsFromImportDecl :: Module
128 -> LImportDecl RdrName
129 -> RnM (GlobalRdrEnv, ImportAvails)
131 importsFromImportDecl this_mod
132 (L loc (ImportDecl loc_imp_mod_name want_boot qual_only as_mod imp_details))
136 -- If there's an error in loadInterface, (e.g. interface
137 -- file not found) we get lots of spurious errors from 'filterImports'
139 imp_mod_name = unLoc loc_imp_mod_name
140 this_mod_name = moduleName this_mod
141 doc = ppr imp_mod_name <+> ptext SLIT("is directly imported")
143 loadSrcInterface doc imp_mod_name want_boot `thenM` \ iface ->
145 -- Compiler sanity check: if the import didn't say
146 -- {-# SOURCE #-} we should not get a hi-boot file
147 WARN( not want_boot && mi_boot iface, ppr imp_mod_name )
149 -- Issue a user warning for a redundant {- SOURCE -} import
150 -- NB that we arrange to read all the ordinary imports before
151 -- any of the {- SOURCE -} imports
152 warnIf (want_boot && not (mi_boot iface))
153 (warnRedundantSourceImport imp_mod_name) `thenM_`
156 imp_mod = mi_module iface
157 deprecs = mi_deprecs iface
158 is_orph = mi_orphan iface
161 filtered_exports = filter not_this_mod (mi_exports iface)
162 not_this_mod (mod,_) = mod /= this_mod_name
163 -- If the module exports anything defined in this module, just ignore it.
164 -- Reason: otherwise it looks as if there are two local definition sites
165 -- for the thing, and an error gets reported. Easiest thing is just to
166 -- filter them out up front. This situation only arises if a module
167 -- imports itself, or another module that imported it. (Necessarily,
168 -- this invoves a loop.)
170 -- Tiresome consequence: if you say
175 -- module B( AType ) where
176 -- import {-# SOURCE #-} A( AType )
178 -- then you'll get a 'B does not export AType' message. Oh well.
180 qual_mod_name = case as_mod of
181 Nothing -> imp_mod_name
182 Just another_name -> another_name
183 imp_spec = ImportSpec { is_mod = imp_mod_name, is_qual = qual_only,
184 is_loc = loc, is_as = qual_mod_name }
187 -- Get the total imports, and filter them according to the import list
188 exportsToAvails filtered_exports `thenM` \ total_avails ->
189 filterImports iface imp_spec
190 imp_details total_avails `thenM` \ (avail_env, gbl_env) ->
193 -- Compute new transitive dependencies
194 orphans | is_orph = insert imp_mod_name (dep_orphs deps)
195 | otherwise = dep_orphs deps
197 (dependent_mods, dependent_pkgs)
198 | isHomeModule imp_mod
199 = -- Imported module is from the home package
200 -- Take its dependent modules and
201 -- (a) remove this_mod (might be there as a hi-boot)
202 -- (b) add imp_mod itself
203 -- Take its dependent packages unchanged
204 ((imp_mod_name, want_boot) : filter not_self (dep_mods deps), dep_pkgs deps)
207 = -- Imported module is from another package
208 -- Dump the dependent modules
209 -- Add the package imp_mod comes from to the dependent packages
211 ([], insert (mi_package iface) (dep_pkgs deps))
213 not_self (m, _) = m /= this_mod_name
215 import_all = case imp_details of
216 Just (is_hiding, ls) -- Imports are spec'd explicitly
217 | not is_hiding -> Just (not (null ls))
218 _ -> Nothing -- Everything is imported,
219 -- (or almost everything [hiding])
221 -- unqual_avails is the Avails that are visible in *unqualified* form
222 -- We need to know this so we know what to export when we see
223 -- module M ( module P ) where ...
224 -- Then we must export whatever came from P unqualified.
225 imports = ImportAvails {
226 imp_qual = unitModuleEnvByName qual_mod_name avail_env,
228 imp_mods = unitModuleEnv imp_mod (imp_mod, import_all),
230 imp_dep_mods = mkModDeps dependent_mods,
231 imp_dep_pkgs = dependent_pkgs }
234 -- Complain if we import a deprecated module
235 ifOptM Opt_WarnDeprecations (
237 DeprecAll txt -> addWarn (moduleDeprec imp_mod_name txt)
241 returnM (gbl_env, imports)
243 exportsToAvails :: [IfaceExport] -> TcRnIf gbl lcl Avails
244 exportsToAvails exports
245 = do { avails_by_module <- mappM do_one exports
246 ; return (concat avails_by_module) }
248 do_one (mod_name, exports) = mapM (do_avail mod_name) exports
249 do_avail mod_nm (Avail n) = do { n' <- lookupOrig mod_nm n;
250 ; return (Avail n') }
251 do_avail mod_nm (AvailTC n ns) = do { n' <- lookupOrig mod_nm n
252 ; ns' <- mappM (lookup_sub n') ns
253 ; return (AvailTC n' ns') }
255 mod = mkPackageModule mod_nm -- Not necessarily right yet
256 lookup_sub parent occ = newGlobalBinder mod occ (Just parent) noSrcLoc
257 -- Hack alert! Notice the newGlobalBinder. It ensures that the subordinate
258 -- names record their parent; and that in turn ensures that the GlobalRdrEnv
259 -- has the correct parent for all the names in its range.
260 -- For imported things, we only suck in the binding site later, if ever.
261 -- Reason for all this:
262 -- Suppose module M exports type A.T, and constructor A.MkT
263 -- Then, we know that A.MkT is a subordinate name of A.T,
264 -- even though we aren't at the binding site of A.T
265 -- And it's important, because we may simply re-export A.T
266 -- without ever sucking in the declaration itself.
268 warnRedundantSourceImport mod_name
269 = ptext SLIT("Unnecessary {- SOURCE -} in the import of module")
270 <+> quotes (ppr mod_name)
274 %************************************************************************
276 importsFromLocalDecls
278 %************************************************************************
280 From the top-level declarations of this module produce
281 * the lexical environment
283 created by its bindings.
285 Complain about duplicate bindings
288 importsFromLocalDecls :: HsGroup RdrName
289 -> RnM (GlobalRdrEnv, ImportAvails)
290 importsFromLocalDecls group
291 = getModule `thenM` \ this_mod ->
292 getLocalDeclBinders this_mod group `thenM` \ avails ->
293 -- The avails that are returned don't include the "system" names
295 all_names :: [Name] -- All the defns; no dups eliminated
296 all_names = [name | avail <- avails, name <- availNames avail]
299 (_, dups) = removeDups compare all_names
301 -- Check for duplicate definitions
302 -- The complaint will come out as "Multiple declarations of Foo.f" because
303 -- since 'f' is in the env twice, the unQualInScope used by the error-msg
304 -- printer returns False. It seems awkward to fix, unfortunately.
305 mappM_ (addErr . dupDeclErr) dups `thenM_`
307 doptM Opt_NoImplicitPrelude `thenM` \ implicit_prelude ->
309 mod_name = moduleName this_mod
310 prov = LocalDef mod_name
311 gbl_env = mkGlobalRdrEnv gres
312 gres = [ GRE { gre_name = name, gre_prov = prov}
315 -- Optimisation: filter out names for built-in syntax
316 -- They just clutter up the environment (esp tuples), and the parser
317 -- will generate Exact RdrNames for them, so the cluttered
318 -- envt is no use. To avoid doing this filter all the time,
319 -- we use -fno-implicit-prelude as a clue that the filter is
320 -- worth while. Really, it's only useful for GHC.Base and GHC.Tuple.
322 -- It's worth doing because it makes the environment smaller for
323 -- every module that imports the Prelude
325 -- Note: don't filter the gbl_env (hence avails, not avails' in
326 -- defn of gbl_env above). Stupid reason: when parsing
327 -- data type decls, the constructors start as Exact tycon-names,
328 -- and then get turned into data con names by zapping the name space;
329 -- but that stops them being Exact, so they get looked up.
330 -- Ditto in fixity decls; e.g. infix 5 :
331 -- Sigh. It doesn't matter because it only affects the Data.Tuple really.
332 -- The important thing is to trim down the exports.
334 avails' | implicit_prelude = filter not_built_in_syntax avails
336 not_built_in_syntax a = not (all isBuiltInSyntaxName (availNames a))
337 -- Only filter it if all the names of the avail are built-in
338 -- In particular, lists have (:) which is not built in syntax
339 -- so we don't filter it out. [Sept 03: wrong: see isBuiltInSyntaxName]
341 avail_env = mkAvailEnv avails'
342 imports = emptyImportAvails {
343 imp_qual = unitModuleEnv this_mod avail_env,
347 returnM (gbl_env, imports)
351 %*********************************************************
353 \subsection{Getting binders out of a declaration}
355 %*********************************************************
357 @getLocalDeclBinders@ returns the names for an @HsDecl@. It's
358 used for source code.
360 *** See "THE NAMING STORY" in HsDecls ****
363 getLocalDeclBinders :: Module -> HsGroup RdrName -> RnM [AvailInfo]
364 getLocalDeclBinders mod (HsGroup {hs_valds = val_decls,
365 hs_tyclds = tycl_decls,
366 hs_fords = foreign_decls })
367 = -- For type and class decls, we generate Global names, with
368 -- no export indicator. They need to be global because they get
369 -- permanently bound into the TyCons and Classes. They don't need
370 -- an export indicator because they are all implicitly exported.
372 mappM new_tc tycl_decls `thenM` \ tc_avails ->
373 mappM new_simple (for_hs_bndrs ++ val_hs_bndrs) `thenM` \ simple_avails ->
374 returnM (tc_avails ++ simple_avails)
376 new_simple rdr_name = newTopSrcBinder mod Nothing rdr_name `thenM` \ name ->
379 val_hs_bndrs = collectGroupBinders val_decls
380 for_hs_bndrs = [nm | L _ (ForeignImport nm _ _ _) <- foreign_decls]
383 = newTopSrcBinder mod Nothing main_rdr `thenM` \ main_name ->
384 mappM (newTopSrcBinder mod (Just main_name)) sub_rdrs `thenM` \ sub_names ->
385 returnM (AvailTC main_name (main_name : sub_names))
387 (main_rdr : sub_rdrs) = tyClDeclNames (unLoc tc_decl)
391 %************************************************************************
393 \subsection{Filtering imports}
395 %************************************************************************
397 @filterImports@ takes the @ExportEnv@ telling what the imported module makes
398 available, and filters it through the import spec (if any).
401 filterImports :: ModIface
402 -> ImportSpec -- The span for the entire import decl
403 -> Maybe (Bool, [Located (IE RdrName)]) -- Import spec; True => hiding
404 -> [AvailInfo] -- What's available
405 -> RnM (AvailEnv, -- What's imported
406 GlobalRdrEnv) -- ...in two forms
408 -- Complains if import spec mentions things that the module doesn't export
409 -- Warns/informs if import spec contains duplicates.
410 mkGenericRdrEnv imp_spec avails
411 = mkGlobalRdrEnv [ GRE { gre_name = name, gre_prov = Imported [imp_spec] False }
412 | avail <- avails, name <- availNames avail ]
414 filterImports iface imp_spec Nothing total_avails
415 = returnM (mkAvailEnv total_avails, mkGenericRdrEnv imp_spec total_avails)
417 filterImports iface imp_spec (Just (want_hiding, import_items)) total_avails
418 = mapAndUnzipM (addLocM get_item) import_items `thenM` \ (avails, gres) ->
420 all_avails = foldr plusAvailEnv emptyAvailEnv avails
421 rdr_env = foldr plusGlobalRdrEnv emptyGlobalRdrEnv gres
423 if not want_hiding then
424 returnM (all_avails, rdr_env)
426 let -- Hide stuff in all_avails
427 hidden = availsToNameSet (availEnvElts all_avails)
428 keep n = not (n `elemNameSet` hidden)
429 pruned_avails = pruneAvails keep total_avails
431 returnM (mkAvailEnv pruned_avails, mkGenericRdrEnv imp_spec pruned_avails)
433 import_fm :: OccEnv AvailInfo
434 import_fm = mkOccEnv [ (nameOccName name, avail)
435 | avail <- total_avails,
436 name <- availNames avail]
437 -- Even though availNames returns data constructors too,
438 -- they won't make any difference because naked entities like T
439 -- in an import list map to TcOccs, not VarOccs.
441 bale_out item = addErr (badImportItemErr iface imp_spec item) `thenM_`
442 returnM (emptyAvailEnv, emptyGlobalRdrEnv)
444 succeed_with :: Bool -> AvailInfo -> RnM (AvailEnv, GlobalRdrEnv)
445 succeed_with all_explicit avail
446 = do { loc <- getSrcSpanM
447 ; returnM (unitAvailEnv avail,
448 mkGlobalRdrEnv (map (mk_gre loc) (availNames avail))) }
450 mk_gre loc name = GRE { gre_name = name,
451 gre_prov = Imported [this_imp_spec loc] (explicit name) }
452 this_imp_spec loc = imp_spec { is_loc = loc }
453 explicit name = all_explicit || name == main_name
454 main_name = availName avail
456 get_item :: IE RdrName -> RnM (AvailEnv, GlobalRdrEnv)
457 -- Empty result for a bad item.
458 -- Singleton result is typical case.
459 -- Can have two when we are hiding, and mention C which might be
460 -- both a class and a data constructor.
461 get_item item@(IEModuleContents _)
464 get_item item@(IEThingAll tc)
465 = case check_item item of
466 Nothing -> bale_out item
467 Just avail@(AvailTC _ [n]) -> -- This occurs when you import T(..), but
468 -- only export T abstractly. The single [n]
469 -- in the AvailTC is the type or class itself
470 ifOptM Opt_WarnMisc (addWarn (dodgyImportWarn tc)) `thenM_`
471 succeed_with False avail
472 Just avail -> succeed_with False avail
474 get_item item@(IEThingAbs n)
475 | want_hiding -- hiding( C )
476 -- Here the 'C' can be a data constructor *or* a type/class
477 = case catMaybes [check_item item, check_item (IEVar data_n)] of
479 avails -> returnM (mkAvailEnv avails, emptyGlobalRdrEnv)
480 -- The GlobalRdrEnv result is irrelevant when hiding
482 data_n = setRdrNameSpace n srcDataName
485 = case check_item item of
486 Nothing -> bale_out item
487 Just avail -> succeed_with True avail
490 | isNothing maybe_in_import_avails ||
491 isNothing maybe_filtered_avail
495 = Just filtered_avail
498 wanted_occ = rdrNameOcc (ieName item)
499 maybe_in_import_avails = lookupOccEnv import_fm wanted_occ
501 Just avail = maybe_in_import_avails
502 maybe_filtered_avail = filterAvail item avail
503 Just filtered_avail = maybe_filtered_avail
507 filterAvail :: IE RdrName -- Wanted
508 -> AvailInfo -- Available
509 -> Maybe AvailInfo -- Resulting available;
510 -- Nothing if (any of the) wanted stuff isn't there
512 filterAvail ie@(IEThingWith want wants) avail@(AvailTC n ns)
513 | sub_names_ok = Just (AvailTC n (filter is_wanted ns))
514 | otherwise = Nothing
516 is_wanted name = nameOccName name `elem` wanted_occs
517 sub_names_ok = all (`elem` avail_occs) wanted_occs
518 avail_occs = map nameOccName ns
519 wanted_occs = map rdrNameOcc (want:wants)
521 filterAvail (IEThingAbs _) (AvailTC n ns) = ASSERT( n `elem` ns )
524 filterAvail (IEThingAbs _) avail@(Avail n) = Just avail -- Type synonyms
526 filterAvail (IEVar _) avail@(Avail n) = Just avail
527 filterAvail (IEVar v) avail@(AvailTC n ns) = Just (AvailTC n (filter wanted ns))
529 wanted n = nameOccName n == occ
531 -- The second equation happens if we import a class op, thus
533 -- where op is a class operation
535 filterAvail (IEThingAll _) avail@(AvailTC _ _) = Just avail
536 -- We don't complain even if the IE says T(..), but
537 -- no constrs/class ops of T are available
538 -- Instead that's caught with a warning by the caller
540 filterAvail ie avail = Nothing
544 %************************************************************************
546 \subsection{Export list processing}
548 %************************************************************************
550 Processing the export list.
552 You might think that we should record things that appear in the export
553 list as ``occurrences'' (using @addOccurrenceName@), but you'd be
554 wrong. We do check (here) that they are in scope, but there is no
555 need to slurp in their actual declaration (which is what
556 @addOccurrenceName@ forces).
558 Indeed, doing so would big trouble when compiling @PrelBase@, because
559 it re-exports @GHC@, which includes @takeMVar#@, whose type includes
560 @ConcBase.StateAndSynchVar#@, and so on...
563 type ExportAccum -- The type of the accumulating parameter of
564 -- the main worker function in exportsFromAvail
565 = ([ModuleName], -- 'module M's seen so far
566 ExportOccMap, -- Tracks exported occurrence names
567 AvailEnv) -- The accumulated exported stuff, kept in an env
568 -- so we can common-up related AvailInfos
569 emptyExportAccum = ([], emptyOccEnv, emptyAvailEnv)
571 type ExportOccMap = OccEnv (Name, IE RdrName)
572 -- Tracks what a particular exported OccName
573 -- in an export list refers to, and which item
574 -- it came from. It's illegal to export two distinct things
575 -- that have the same occurrence name
578 exportsFromAvail :: Bool -- False => no 'module M(..) where' header at all
579 -> Maybe [Located (IE RdrName)] -- Nothing => no explicit export list
581 -- Complains if two distinct exports have same OccName
582 -- Warns about identical exports.
583 -- Complains about exports items not in scope
585 exportsFromAvail explicit_mod exports
586 = do { TcGblEnv { tcg_rdr_env = rdr_env,
587 tcg_imports = imports } <- getGblEnv ;
589 -- If the module header is omitted altogether, then behave
590 -- as if the user had written "module Main(main) where..."
591 -- EXCEPT in interactive mode, when we behave as if he had
592 -- written "module Main where ..."
593 -- Reason: don't want to complain about 'main' not in scope
594 -- in interactive mode
595 ghci_mode <- getGhciMode ;
597 | explicit_mod = exports
598 | ghci_mode == Interactive = Nothing
599 | otherwise = Just [noLoc (IEVar main_RDR_Unqual)] } ;
600 exports_from_avail real_exports rdr_env imports }
603 exports_from_avail Nothing rdr_env
604 imports@(ImportAvails { imp_env = entity_avail_env })
605 = -- Export all locally-defined things
606 -- We do this by filtering the global RdrEnv,
607 -- keeping only things that are (a) qualified,
608 -- (b) locally defined, (c) a 'main' name
609 -- Then we look up in the entity-avail-env
610 return [ lookupAvailEnv entity_avail_env name
611 | gre <- globalRdrEnvElts rdr_env,
613 let name = gre_name gre,
614 isNothing (nameParent_maybe name) -- Main things only
617 exports_from_avail (Just export_items) rdr_env
618 (ImportAvails { imp_qual = mod_avail_env,
619 imp_env = entity_avail_env })
620 = foldlM (exports_from_litem) emptyExportAccum
621 export_items `thenM` \ (_, _, export_avail_map) ->
622 returnM (nameEnvElts export_avail_map)
625 exports_from_litem :: ExportAccum -> Located (IE RdrName) -> RnM ExportAccum
626 exports_from_litem acc = addLocM (exports_from_item acc)
628 exports_from_item :: ExportAccum -> IE RdrName -> RnM ExportAccum
629 exports_from_item acc@(mods, occs, avails) ie@(IEModuleContents mod)
630 | mod `elem` mods -- Duplicate export of M
631 = do { warn_dup_exports <- doptM Opt_WarnDuplicateExports ;
632 warnIf warn_dup_exports (dupModuleExport mod) ;
636 = case lookupModuleEnvByName mod_avail_env mod of
637 Nothing -> addErr (modExportErr mod) `thenM_`
642 mod_avails = [ filtered_avail
643 | avail <- availEnvElts avail_env,
644 let mb_avail = filter_unqual rdr_env avail,
646 let Just filtered_avail = mb_avail]
648 avails' = foldl addAvail avails mod_avails
650 -- This check_occs not only finds conflicts between this item
651 -- and others, but also internally within this item. That is,
652 -- if 'M.x' is in scope in several ways, we'll have several
653 -- members of mod_avails with the same OccName.
655 foldlM (check_occs ie) occs mod_avails `thenM` \ occs' ->
656 returnM (mod:mods, occs', avails')
658 exports_from_item acc@(mods, occs, avails) ie
659 = lookupGlobalOccRn (ieName ie) `thenM` \ name ->
660 if isUnboundName name then
661 returnM acc -- Avoid error cascade
663 -- Get the AvailInfo for the parent of the specified name
665 parent = nameParent name
666 avail = lookupAvailEnv entity_avail_env parent
668 -- Filter out the bits we want
669 case filterAvail ie avail of {
670 Nothing -> -- Not enough availability
671 addErr (exportItemErr ie) `thenM_`
676 -- Phew! It's OK! Now to check the occurrence stuff!
677 checkForDodgyExport ie avail `thenM_`
678 check_occs ie occs export_avail `thenM` \ occs' ->
679 returnM (mods, occs', addAvail avails export_avail)
683 -------------------------------
684 filter_unqual :: GlobalRdrEnv -> AvailInfo -> Maybe AvailInfo
685 -- Filter the Avail by what's in scope unqualified
686 filter_unqual env (Avail n)
687 | in_scope env n = Just (Avail n)
688 | otherwise = Nothing
689 filter_unqual env (AvailTC n ns)
690 | not (null ns') = Just (AvailTC n ns')
691 | otherwise = Nothing
693 ns' = filter (in_scope env) ns
695 in_scope :: GlobalRdrEnv -> Name -> Bool
696 -- Checks whether the Name is in scope unqualified,
697 -- regardless of whether it's ambiguous or not
698 in_scope env n = any unQualOK (lookupGRE_Name env n)
700 -------------------------------
701 checkForDodgyExport :: IE RdrName -> AvailInfo -> RnM ()
702 checkForDodgyExport (IEThingAll tc) (AvailTC _ [n]) = addWarn (dodgyExportWarn tc)
703 -- This occurs when you import T(..), but
704 -- only export T abstractly. The single [n]
705 -- in the AvailTC is the type or class itself
706 checkForDodgyExport _ _ = return ()
708 -------------------------------
709 check_occs :: IE RdrName -> ExportOccMap -> AvailInfo -> RnM ExportOccMap
710 check_occs ie occs avail
711 = foldlM check occs (availNames avail)
714 = case lookupOccEnv occs name_occ of
715 Nothing -> returnM (extendOccEnv occs name_occ (name, ie))
718 | name == name' -- Duplicate export
719 -> do { warn_dup_exports <- doptM Opt_WarnDuplicateExports ;
720 warnIf warn_dup_exports (dupExportWarn name_occ ie ie') ;
723 | otherwise -- Same occ name but different names: an error
724 -> do { global_env <- getGlobalRdrEnv ;
725 addErr (exportClashErr global_env name name' ie ie') ;
728 name_occ = nameOccName name
731 %*********************************************************
733 \subsection{Unused names}
735 %*********************************************************
738 reportUnusedNames :: TcGblEnv -> RnM ()
739 reportUnusedNames gbl_env
740 = do { warnDeprecations defined_and_used
741 ; warnUnusedTopBinds unused_locals
742 ; warnUnusedModules unused_imp_mods
743 ; warnUnusedImports unused_imports
744 ; warnDuplicateImports dup_imps
745 ; printMinimalImports minimal_imports }
747 used_names, all_used_names :: NameSet
748 used_names = findUses (tcg_dus gbl_env) emptyNameSet
749 all_used_names = used_names `unionNameSets`
750 mkNameSet (mapCatMaybes nameParent_maybe (nameSetToList used_names))
751 -- A use of C implies a use of T,
752 -- if C was brought into scope by T(..) or T(C)
754 -- Collect the defined names from the in-scope environment
755 defined_names :: [GlobalRdrElt]
756 defined_names = globalRdrEnvElts (tcg_rdr_env gbl_env)
758 -- Note that defined_and_used, defined_but_not_used
759 -- are both [GRE]; that's why we need defined_and_used
760 -- rather than just all_used_names
761 defined_and_used, defined_but_not_used :: [GlobalRdrElt]
762 (defined_and_used, defined_but_not_used) = partition is_used defined_names
763 is_used gre = gre_name gre `elemNameSet` all_used_names
765 -- Find the duplicate imports
766 dup_imps = filter is_dup defined_and_used
767 is_dup (GRE {gre_prov = Imported imp_spec True}) = not (isSingleton imp_spec)
770 -- Filter out the ones that are
771 -- (a) defined in this module, and
772 -- (b) not defined by a 'deriving' clause
773 -- The latter have an Internal Name, so we can filter them out easily
774 unused_locals :: [GlobalRdrElt]
775 unused_locals = filter is_unused_local defined_but_not_used
776 is_unused_local :: GlobalRdrElt -> Bool
777 is_unused_local gre = isLocalGRE gre && isExternalName (gre_name gre)
779 unused_imports :: [GlobalRdrElt]
780 unused_imports = filter unused_imp defined_but_not_used
781 unused_imp (GRE {gre_prov = Imported imp_specs True})
782 = not (all (module_unused . is_mod) imp_specs)
783 -- Don't complain about unused imports if we've already said the
784 -- entire import is unused
785 unused_imp other = False
787 -- To figure out the minimal set of imports, start with the things
788 -- that are in scope (i.e. in gbl_env). Then just combine them
789 -- into a bunch of avails, so they are properly grouped
790 minimal_imports :: FiniteMap ModuleName AvailEnv
791 minimal_imports0 = emptyFM
792 minimal_imports1 = foldr add_name minimal_imports0 defined_and_used
793 minimal_imports = foldr add_inst_mod minimal_imports1 direct_import_mods
794 -- The last line makes sure that we retain all direct imports
795 -- even if we import nothing explicitly.
796 -- It's not necessarily redundant to import such modules. Consider
800 -- The import M() is not *necessarily* redundant, even if
801 -- we suck in no instance decls from M (e.g. it contains
802 -- no instance decls, or This contains no code). It may be
803 -- that we import M solely to ensure that M's orphan instance
804 -- decls (or those in its imports) are visible to people who
805 -- import This. Sigh.
806 -- There's really no good way to detect this, so the error message
807 -- in RnEnv.warnUnusedModules is weakened instead
809 -- We've carefully preserved the provenance so that we can
810 -- construct minimal imports that import the name by (one of)
811 -- the same route(s) as the programmer originally did.
812 add_name (GRE {gre_name = n,
813 gre_prov = Imported imp_specs _}) acc
814 = addToFM_C plusAvailEnv acc (is_mod (head imp_specs))
815 (unitAvailEnv (mk_avail n (nameParent_maybe n)))
819 -- n is the name of the thing, p is the name of its parent
820 mk_avail n (Just p) = AvailTC p [p,n]
821 mk_avail n Nothing | isTcOcc (nameOccName n) = AvailTC n [n]
822 | otherwise = Avail n
825 | m `elemFM` acc = acc -- We import something already
826 | otherwise = addToFM acc m emptyAvailEnv
827 -- Add an empty collection of imports for a module
828 -- from which we have sucked only instance decls
830 imports = tcg_imports gbl_env
832 direct_import_mods :: [ModuleName]
833 direct_import_mods = map (moduleName . fst)
834 (moduleEnvElts (imp_mods imports))
836 hasEmptyImpList :: ModuleName -> Bool
838 case lookupModuleEnvByName (imp_mods imports) m of
839 Just (_,Just x) -> not x
842 -- unused_imp_mods are the directly-imported modules
843 -- that are not mentioned in minimal_imports1
844 -- [Note: not 'minimal_imports', because that includes directly-imported
845 -- modules even if we use nothing from them; see notes above]
846 unused_imp_mods = [m | m <- direct_import_mods,
847 isNothing (lookupFM minimal_imports1 m),
849 not (hasEmptyImpList m)]
850 -- hasEmptyImpList arranges not to complain about
851 -- import M (), which is an idiom for importing
852 -- instance declarations
854 module_unused :: ModuleName -> Bool
855 module_unused mod = mod `elem` unused_imp_mods
858 ---------------------
859 warnDeprecations :: [GlobalRdrElt] -> RnM ()
860 warnDeprecations used_gres
861 = ifOptM Opt_WarnDeprecations $
864 ; mapM_ (check hpt (eps_PIT eps)) used_gres }
866 check hpt pit (GRE {gre_name = name, gre_prov = Imported (imp_spec:_) _})
867 | Just deprec_txt <- lookupDeprec hpt pit name
868 = addSrcSpan (is_loc imp_spec) $
869 addWarn (sep [ptext SLIT("Deprecated use of") <+>
870 text (occNameFlavour (nameOccName name)) <+>
875 name_mod = nameModuleName name
876 imp_mod = is_mod imp_spec
877 imp_msg = ptext SLIT("imported from") <+> ppr imp_mod <> extra
878 extra | imp_mod == name_mod = empty
879 | otherwise = ptext SLIT(", but defined in") <+> ppr name_mod
881 check hpt pit ok_gre = returnM () -- Local, or not deprectated
882 -- The Imported pattern-match: don't deprecate locally defined names
883 -- For a start, we may be exporting a deprecated thing
884 -- Also we may use a deprecated thing in the defn of another
885 -- deprecated things. We may even use a deprecated thing in
886 -- the defn of a non-deprecated thing, when changing a module's
889 lookupDeprec :: HomePackageTable -> PackageIfaceTable
890 -> Name -> Maybe DeprecTxt
891 lookupDeprec hpt pit n
892 = case lookupIface hpt pit (nameModule n) of
893 Just iface -> mi_dep_fn iface n `seqMaybe` -- Bleat if the thing, *or
894 mi_dep_fn iface (nameParent n) -- its parent*, is deprec'd
895 Nothing -> pprPanic "lookupDeprec" (ppr n)
896 -- By now all the interfaces should have been loaded
898 ---------------------
899 warnDuplicateImports :: [GlobalRdrElt] -> RnM ()
900 warnDuplicateImports gres
901 = ifOptM Opt_WarnUnusedImports (mapM_ warn gres)
903 warn (GRE { gre_name = name, gre_prov = Imported imps _ })
904 = addWarn ((quotes (ppr name) <+> ptext SLIT("is imported more than once:"))
905 $$ nest 2 (vcat (map ppr imps)))
908 -- ToDo: deal with original imports with 'qualified' and 'as M' clauses
909 printMinimalImports :: FiniteMap ModuleName AvailEnv -- Minimal imports
911 printMinimalImports imps
912 = ifOptM Opt_D_dump_minimal_imports $ do {
914 mod_ies <- mappM to_ies (fmToList imps) ;
915 this_mod <- getModule ;
916 rdr_env <- getGlobalRdrEnv ;
917 ioToTcRn (do { h <- openFile (mkFilename this_mod) WriteMode ;
918 printForUser h (unQualInScope rdr_env)
919 (vcat (map ppr_mod_ie mod_ies)) })
922 mkFilename this_mod = moduleNameUserString (moduleName this_mod) ++ ".imports"
923 ppr_mod_ie (mod_name, ies)
924 | mod_name == pRELUDE_Name
926 | null ies -- Nothing except instances comes from here
927 = ptext SLIT("import") <+> ppr mod_name <> ptext SLIT("() -- Instances only")
929 = ptext SLIT("import") <+> ppr mod_name <>
930 parens (fsep (punctuate comma (map ppr ies)))
932 to_ies (mod, avail_env) = mappM to_ie (availEnvElts avail_env) `thenM` \ ies ->
935 to_ie :: AvailInfo -> RnM (IE Name)
936 -- The main trick here is that if we're importing all the constructors
937 -- we want to say "T(..)", but if we're importing only a subset we want
938 -- to say "T(A,B,C)". So we have to find out what the module exports.
939 to_ie (Avail n) = returnM (IEVar n)
940 to_ie (AvailTC n [m]) = ASSERT( n==m )
941 returnM (IEThingAbs n)
943 = loadSrcInterface doc n_mod False `thenM` \ iface ->
944 case [xs | (m,as) <- mi_exports iface,
947 x == nameOccName n] of
948 [xs] | all_used xs -> returnM (IEThingAll n)
949 | otherwise -> returnM (IEThingWith n (filter (/= n) ns))
950 other -> pprTrace "to_ie" (ppr n <+> ppr n_mod <+> ppr other) $
953 all_used avail_occs = all (`elem` map nameOccName ns) avail_occs
954 doc = text "Compute minimal imports from" <+> ppr n
955 n_mod = nameModuleName n
959 %************************************************************************
963 %************************************************************************
966 badImportItemErr iface imp_spec ie
967 = sep [ptext SLIT("Module"), quotes (ppr (is_mod imp_spec)), source_import,
968 ptext SLIT("does not export"), quotes (ppr ie)]
970 source_import | mi_boot iface = ptext SLIT("(hi-boot interface)")
973 dodgyImportWarn item = dodgyMsg (ptext SLIT("import")) item
974 dodgyExportWarn item = dodgyMsg (ptext SLIT("export")) item
977 = sep [ ptext SLIT("The") <+> kind <+> ptext SLIT("item") <+> quotes (ppr (IEThingAll tc)),
978 ptext SLIT("suggests that") <+> quotes (ppr tc) <+> ptext SLIT("has constructor or class methods"),
979 ptext SLIT("but it has none; it is a type synonym or abstract type or class") ]
982 = hsep [ ptext SLIT("Unknown module in export list: module"), quotes (ppr mod)]
984 exportItemErr export_item
985 = sep [ ptext SLIT("The export item") <+> quotes (ppr export_item),
986 ptext SLIT("attempts to export constructors or class methods that are not visible here") ]
988 exportClashErr global_env name1 name2 ie1 ie2
989 = vcat [ ptext SLIT("Conflicting exports for") <+> quotes (ppr occ) <> colon
990 , ppr_export ie1 name1
991 , ppr_export ie2 name2 ]
993 occ = nameOccName name1
994 ppr_export ie name = nest 2 (quotes (ppr ie) <+> ptext SLIT("exports") <+>
995 quotes (ppr name) <+> pprNameProvenance (get_gre name))
997 -- get_gre finds a GRE for the Name, so that we can show its provenance
999 = case lookupGRE_Name global_env name of
1001 [] -> pprPanic "exportClashErr" (ppr name)
1004 = vcat [ptext SLIT("Multiple declarations of") <+> quotes (ppr n),
1005 nest 4 (vcat (map ppr sorted_locs))]
1007 sorted_locs = sortLt occ'ed_before (map nameSrcLoc (n:ns))
1008 occ'ed_before a b = LT == compare a b
1010 dupExportWarn occ_name ie1 ie2
1011 = hsep [quotes (ppr occ_name),
1012 ptext SLIT("is exported by"), quotes (ppr ie1),
1013 ptext SLIT("and"), quotes (ppr ie2)]
1016 = hsep [ptext SLIT("Duplicate"),
1017 quotes (ptext SLIT("Module") <+> ppr mod),
1018 ptext SLIT("in export list")]
1020 moduleDeprec mod txt
1021 = sep [ ptext SLIT("Module") <+> quotes (ppr mod) <+> ptext SLIT("is deprecated:"),