2 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
4 \section[RnNames]{Extracting imported and top-level names in scope}
8 rnImports, importsFromLocalDecls,
9 reportUnusedNames, reportDeprecations,
10 mkModDeps, exportsToAvails, exportsFromAvail
13 #include "HsVersions.h"
15 import CmdLineOpts ( DynFlag(..) )
16 import HsSyn ( IE(..), ieName, ImportDecl(..), LImportDecl,
17 ForeignDecl(..), HsGroup(..), HsBindGroup(..),
18 Sig(..), collectGroupBinders, tyClDeclNames
21 import IfaceEnv ( lookupAvail )
22 import LoadIface ( loadSrcInterface )
26 import PrelNames ( pRELUDE, isUnboundName, main_RDR_Unqual )
27 import Module ( Module, moduleUserString, unitModuleEnv,
28 lookupModuleEnv, moduleEnvElts, foldModuleEnv )
29 import Name ( Name, nameSrcLoc, nameOccName, nameModule, isWiredInName,
30 nameParent, nameParent_maybe, isExternalName,
34 import OccName ( srcDataName, isTcOcc, occNameFlavour, OccEnv,
35 mkOccEnv, lookupOccEnv, emptyOccEnv, extendOccEnv )
36 import HscTypes ( GenAvailInfo(..), AvailInfo, GhciMode(..),
37 IfaceExport, HomePackageTable, PackageIfaceTable,
38 availNames, unQualInScope,
39 Deprecs(..), ModIface(..), Dependencies(..),
40 lookupIface, ExternalPackageState(..)
42 import Packages ( PackageIdH(..) )
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 ( isNothing, catMaybes, mapCatMaybes, seqMaybe, orElse )
51 import SrcLoc ( Located(..), mkGeneralSrcSpan,
52 unLoc, noLoc, srcLocSpan, combineSrcSpans, SrcSpan )
53 import BasicTypes ( DeprecTxt )
54 import ListSetOps ( removeDups )
55 import Util ( sortLe, notNull, isSingleton )
56 import List ( partition )
57 import IO ( openFile, IOMode(..) )
62 %************************************************************************
66 %************************************************************************
69 rnImports :: [LImportDecl RdrName]
70 -> RnM (GlobalRdrEnv, ImportAvails)
73 = do { -- PROCESS IMPORT DECLS
74 -- Do the non {- SOURCE -} ones first, so that we get a helpful
75 -- warning for {- SOURCE -} ones that are unnecessary
77 ; implicit_prelude <- doptM Opt_ImplicitPrelude
79 all_imports = mk_prel_imports this_mod implicit_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 ; stuff1 <- mappM get_imports ordinary
86 ; stuff2 <- mappM get_imports source
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 ; return (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 implicit_prelude
104 | this_mod == pRELUDE
105 || explicit_prelude_import
106 || not implicit_prelude
109 | otherwise = [preludeImportDecl]
111 explicit_prelude_import
112 = notNull [ () | L _ (ImportDecl mod _ _ _ _) <- imports,
113 unLoc mod == pRELUDE ]
117 ImportDecl (L loc pRELUDE)
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 doc = ppr imp_mod_name <+> ptext SLIT("is directly imported")
142 loadSrcInterface doc imp_mod_name want_boot `thenM` \ iface ->
144 -- Compiler sanity check: if the import didn't say
145 -- {-# SOURCE #-} we should not get a hi-boot file
146 WARN( not want_boot && mi_boot iface, ppr imp_mod_name )
148 -- Issue a user warning for a redundant {- SOURCE -} import
149 -- NB that we arrange to read all the ordinary imports before
150 -- any of the {- SOURCE -} imports
151 warnIf (want_boot && not (mi_boot iface))
152 (warnRedundantSourceImport imp_mod_name) `thenM_`
155 imp_mod = mi_module iface
156 deprecs = mi_deprecs iface
157 is_orph = mi_orphan iface
160 filtered_exports = filter not_this_mod (mi_exports iface)
161 not_this_mod (mod,_) = mod /= this_mod
162 -- If the module exports anything defined in this module, just ignore it.
163 -- Reason: otherwise it looks as if there are two local definition sites
164 -- for the thing, and an error gets reported. Easiest thing is just to
165 -- filter them out up front. This situation only arises if a module
166 -- imports itself, or another module that imported it. (Necessarily,
167 -- this invoves a loop.)
169 -- Tiresome consequence: if you say
174 -- module B( AType ) where
175 -- import {-# SOURCE #-} A( AType )
177 -- then you'll get a 'B does not export AType' message. Oh well.
179 qual_mod_name = case as_mod of
180 Nothing -> imp_mod_name
181 Just another_name -> another_name
182 imp_spec = ImportSpec { is_mod = imp_mod_name, is_qual = qual_only,
183 is_loc = loc, is_as = qual_mod_name }
185 -- Get the total imports, and filter them according to the import list
186 exportsToAvails filtered_exports `thenM` \ total_avails ->
187 filterImports iface imp_spec
188 imp_details total_avails `thenM` \ (avail_env, gbl_env) ->
190 getDOpts `thenM` \ dflags ->
193 -- Compute new transitive dependencies
195 orphans | is_orph = ASSERT( not (imp_mod_name `elem` dep_orphs deps) )
196 imp_mod_name : dep_orphs deps
197 | otherwise = dep_orphs deps
199 (dependent_mods, dependent_pkgs)
200 = case mi_package iface of
202 -- Imported module is from the home package
203 -- Take its dependent modules and add imp_mod itself
204 -- Take its dependent packages unchanged
206 -- NB: (dep_mods deps) might include a hi-boot file
207 -- for the module being compiled, CM. Do *not* filter
208 -- this out (as we used to), because when we've
209 -- finished dealing with the direct imports we want to
210 -- know if any of them depended on CM.hi-boot, in
211 -- which case we should do the hi-boot consistency
212 -- check. See LoadIface.loadHiBootInterface
213 ((imp_mod_name, want_boot) : dep_mods deps, dep_pkgs deps)
216 -- Imported module is from another package
217 -- Dump the dependent modules
218 -- Add the package imp_mod comes from to the dependent packages
219 ASSERT2( not (pkg `elem` dep_pkgs deps), ppr pkg <+> ppr (dep_pkgs deps) )
220 ([], pkg : dep_pkgs deps)
222 import_all = case imp_details of
223 Just (is_hiding, ls) -- Imports are spec'd explicitly
224 | not is_hiding -> Just (not (null ls))
225 _ -> Nothing -- Everything is imported,
226 -- (or almost everything [hiding])
228 -- unqual_avails is the Avails that are visible in *unqualified* form
229 -- We need to know this so we know what to export when we see
230 -- module M ( module P ) where ...
231 -- Then we must export whatever came from P unqualified.
232 imports = ImportAvails {
233 imp_env = unitModuleEnv qual_mod_name avail_env,
234 imp_mods = unitModuleEnv imp_mod (imp_mod, import_all, loc),
236 imp_dep_mods = mkModDeps dependent_mods,
237 imp_dep_pkgs = dependent_pkgs }
240 -- Complain if we import a deprecated module
241 ifOptM Opt_WarnDeprecations (
243 DeprecAll txt -> addWarn (moduleDeprec imp_mod_name txt)
247 returnM (gbl_env, imports)
249 exportsToAvails :: [IfaceExport] -> TcRnIf gbl lcl NameSet
250 exportsToAvails exports
251 = foldlM do_one emptyNameSet exports
253 do_one acc (mod, exports) = foldlM (do_avail mod) acc exports
254 do_avail mod acc avail = do { ns <- lookupAvail mod avail
255 ; return (addListToNameSet acc ns) }
257 warnRedundantSourceImport mod_name
258 = ptext SLIT("Unnecessary {- SOURCE -} in the import of module")
259 <+> quotes (ppr mod_name)
263 %************************************************************************
265 importsFromLocalDecls
267 %************************************************************************
269 From the top-level declarations of this module produce
270 * the lexical environment
272 created by its bindings.
274 Complain about duplicate bindings
277 importsFromLocalDecls :: HsGroup RdrName
278 -> RnM (GlobalRdrEnv, ImportAvails)
279 importsFromLocalDecls group
280 = getModule `thenM` \ this_mod ->
281 getLocalDeclBinders this_mod group `thenM` \ avails ->
282 -- The avails that are returned don't include the "system" names
284 all_names :: [Name] -- All the defns; no dups eliminated
285 all_names = [name | avail <- avails, name <- availNames avail]
288 (_, dups) = removeDups compare all_names
290 -- Check for duplicate definitions
291 -- The complaint will come out as "Multiple declarations of Foo.f" because
292 -- since 'f' is in the env twice, the unQualInScope used by the error-msg
293 -- printer returns False. It seems awkward to fix, unfortunately.
294 mappM_ addDupDeclErr dups `thenM_`
296 doptM Opt_ImplicitPrelude `thenM` \ implicit_prelude ->
298 prov = LocalDef this_mod
299 gbl_env = mkGlobalRdrEnv gres
300 gres = [ GRE { gre_name = name, gre_prov = prov}
303 -- Optimisation: filter out names for built-in syntax
304 -- They just clutter up the environment (esp tuples), and the parser
305 -- will generate Exact RdrNames for them, so the cluttered
306 -- envt is no use. To avoid doing this filter all the time,
307 -- we use -fno-implicit-prelude as a clue that the filter is
308 -- worth while. Really, it's only useful for GHC.Base and GHC.Tuple.
310 -- It's worth doing because it makes the environment smaller for
311 -- every module that imports the Prelude
313 -- Note: don't filter the gbl_env (hence all_names, not filered_all_names
314 -- in defn of gres above). Stupid reason: when parsing
315 -- data type decls, the constructors start as Exact tycon-names,
316 -- and then get turned into data con names by zapping the name space;
317 -- but that stops them being Exact, so they get looked up.
318 -- Ditto in fixity decls; e.g. infix 5 :
319 -- Sigh. It doesn't matter because it only affects the Data.Tuple really.
320 -- The important thing is to trim down the exports.
322 | implicit_prelude = all_names
323 | otherwise = filter (not . isBuiltInSyntax) all_names
325 imports = emptyImportAvails {
326 imp_env = unitModuleEnv this_mod $
327 mkNameSet filtered_names
330 returnM (gbl_env, imports)
334 %*********************************************************
336 \subsection{Getting binders out of a declaration}
338 %*********************************************************
340 @getLocalDeclBinders@ returns the names for an @HsDecl@. It's
341 used for source code.
343 *** See "THE NAMING STORY" in HsDecls ****
346 getLocalDeclBinders :: Module -> HsGroup RdrName -> RnM [AvailInfo]
347 getLocalDeclBinders mod (HsGroup {hs_valds = val_decls,
348 hs_tyclds = tycl_decls,
349 hs_fords = foreign_decls })
350 = -- For type and class decls, we generate Global names, with
351 -- no export indicator. They need to be global because they get
352 -- permanently bound into the TyCons and Classes. They don't need
353 -- an export indicator because they are all implicitly exported.
355 mappM new_tc tycl_decls `thenM` \ tc_avails ->
357 -- In a hs-boot file, the value binders come from the
358 -- *signatures*, and there should be no foreign binders
359 tcIsHsBoot `thenM` \ is_hs_boot ->
360 let val_bndrs | is_hs_boot = sig_hs_bndrs
361 | otherwise = for_hs_bndrs ++ val_hs_bndrs
363 mappM new_simple val_bndrs `thenM` \ names ->
365 returnM (tc_avails ++ map Avail names)
367 new_simple rdr_name = newTopSrcBinder mod Nothing rdr_name
369 sig_hs_bndrs = [nm | HsBindGroup _ lsigs _ <- val_decls,
370 L _ (Sig nm _) <- lsigs]
371 val_hs_bndrs = collectGroupBinders val_decls
372 for_hs_bndrs = [nm | L _ (ForeignImport nm _ _ _) <- foreign_decls]
375 = newTopSrcBinder mod Nothing main_rdr `thenM` \ main_name ->
376 mappM (newTopSrcBinder mod (Just main_name)) sub_rdrs `thenM` \ sub_names ->
377 returnM (AvailTC main_name (main_name : sub_names))
379 (main_rdr : sub_rdrs) = tyClDeclNames (unLoc tc_decl)
383 %************************************************************************
385 \subsection{Filtering imports}
387 %************************************************************************
389 @filterImports@ takes the @ExportEnv@ telling what the imported module makes
390 available, and filters it through the import spec (if any).
393 filterImports :: ModIface
394 -> ImportSpec -- The span for the entire import decl
395 -> Maybe (Bool, [Located (IE RdrName)]) -- Import spec; True => hiding
396 -> NameSet -- What's available
397 -> RnM (NameSet, -- What's imported (qualified or unqualified)
398 GlobalRdrEnv) -- Same again, but in GRE form
400 -- Complains if import spec mentions things that the module doesn't export
401 -- Warns/informs if import spec contains duplicates.
403 mkGenericRdrEnv imp_spec names
404 = mkGlobalRdrEnv [ GRE { gre_name = name, gre_prov = Imported [imp_spec] False }
405 | name <- nameSetToList names ]
407 filterImports iface imp_spec Nothing all_names
408 = returnM (all_names, mkGenericRdrEnv imp_spec all_names)
410 filterImports iface imp_spec (Just (want_hiding, import_items)) all_names
411 = mappM (addLocM get_item) import_items `thenM` \ gres_s ->
414 specified_names = mkNameSet (map gre_name gres)
416 if not want_hiding then
417 return (specified_names, mkGlobalRdrEnv gres)
420 keep n = not (n `elemNameSet` specified_names)
421 pruned_avails = filterNameSet keep all_names
423 return (pruned_avails, mkGenericRdrEnv imp_spec pruned_avails)
426 occ_env :: OccEnv Name -- Maps OccName to corresponding Name
427 occ_env = mkOccEnv [(nameOccName n, n) | n <- nameSetToList all_names]
428 -- This env will have entries for data constructors too,
429 -- they won't make any difference because naked entities like T
430 -- in an import list map to TcOccs, not VarOccs.
432 sub_env :: NameEnv [Name]
433 sub_env = mkSubNameEnv all_names
435 bale_out item = addErr (badImportItemErr iface imp_spec item) `thenM_`
438 succeed_with :: Bool -> [Name] -> RnM [GlobalRdrElt]
439 succeed_with all_explicit names
440 = do { loc <- getSrcSpanM
441 ; returnM (map (mk_gre loc) names) }
443 mk_gre loc name = GRE { gre_name = name,
444 gre_prov = Imported [this_imp_spec loc] (explicit name) }
445 this_imp_spec loc = imp_spec { is_loc = loc }
446 explicit name = all_explicit || isNothing (nameParent_maybe name)
448 get_item :: IE RdrName -> RnM [GlobalRdrElt]
449 -- Empty result for a bad item.
450 -- Singleton result is typical case.
451 -- Can have two when we are hiding, and mention C which might be
452 -- both a class and a data constructor.
453 get_item item@(IEModuleContents _)
456 get_item item@(IEThingAll tc)
457 = case check_item item of
460 [n] -> -- This occurs when you import T(..), but
461 -- only export T abstractly. The single [n]
462 -- in the AvailTC is the type or class itself
463 ifOptM Opt_WarnDodgyImports (addWarn (dodgyImportWarn tc)) `thenM_`
464 succeed_with False [n]
466 names -> succeed_with False names
468 get_item item@(IEThingAbs n)
469 | want_hiding -- hiding( C )
470 -- Here the 'C' can be a data constructor
471 -- *or* a type/class, or even both
472 = case concat [check_item item, check_item (IEVar data_n)] of
474 names -> succeed_with True names
476 data_n = setRdrNameSpace n srcDataName
479 = case check_item item of
481 names -> succeed_with True names
483 check_item :: IE RdrName -> [Name]
485 = case lookupOccEnv occ_env (rdrNameOcc (ieName item)) of
487 Just name -> filterAvail item name sub_env
491 %************************************************************************
493 \subsection{Export list processing}
495 %************************************************************************
497 Processing the export list.
499 You might think that we should record things that appear in the export
500 list as ``occurrences'' (using @addOccurrenceName@), but you'd be
501 wrong. We do check (here) that they are in scope, but there is no
502 need to slurp in their actual declaration (which is what
503 @addOccurrenceName@ forces).
505 Indeed, doing so would big trouble when compiling @PrelBase@, because
506 it re-exports @GHC@, which includes @takeMVar#@, whose type includes
507 @ConcBase.StateAndSynchVar#@, and so on...
510 type ExportAccum -- The type of the accumulating parameter of
511 -- the main worker function in exportsFromAvail
512 = ([Module], -- 'module M's seen so far
513 ExportOccMap, -- Tracks exported occurrence names
514 NameSet) -- The accumulated exported stuff
515 emptyExportAccum = ([], emptyOccEnv, emptyNameSet)
517 type ExportOccMap = OccEnv (Name, IE RdrName)
518 -- Tracks what a particular exported OccName
519 -- in an export list refers to, and which item
520 -- it came from. It's illegal to export two distinct things
521 -- that have the same occurrence name
524 exportsFromAvail :: Bool -- False => no 'module M(..) where' header at all
525 -> Maybe [Located (IE RdrName)] -- Nothing => no explicit export list
527 -- Complains if two distinct exports have same OccName
528 -- Warns about identical exports.
529 -- Complains about exports items not in scope
531 exportsFromAvail explicit_mod exports
532 = do { TcGblEnv { tcg_rdr_env = rdr_env,
533 tcg_imports = imports } <- getGblEnv ;
535 -- If the module header is omitted altogether, then behave
536 -- as if the user had written "module Main(main) where..."
537 -- EXCEPT in interactive mode, when we behave as if he had
538 -- written "module Main where ..."
539 -- Reason: don't want to complain about 'main' not in scope
540 -- in interactive mode
541 ghci_mode <- getGhciMode ;
543 | explicit_mod = exports
544 | ghci_mode == Interactive = Nothing
545 | otherwise = Just [noLoc (IEVar main_RDR_Unqual)] } ;
546 exports_from_avail real_exports rdr_env imports }
549 exports_from_avail Nothing rdr_env imports
550 = -- Export all locally-defined things
551 -- We do this by filtering the global RdrEnv,
552 -- keeping only things that are locally-defined
553 return (mkNameSet [ gre_name gre
554 | gre <- globalRdrEnvElts rdr_env,
557 exports_from_avail (Just items) rdr_env (ImportAvails { imp_env = imp_env })
558 = foldlM do_litem emptyExportAccum items `thenM` \ (_, _, exports) ->
561 sub_env :: NameEnv [Name] -- Classify each name by its parent
562 sub_env = mkSubNameEnv (foldModuleEnv unionNameSets emptyNameSet imp_env)
564 do_litem :: ExportAccum -> Located (IE RdrName) -> RnM ExportAccum
565 do_litem acc = addLocM (exports_from_item acc)
567 exports_from_item :: ExportAccum -> IE RdrName -> RnM ExportAccum
568 exports_from_item acc@(mods, occs, exports) ie@(IEModuleContents mod)
569 | mod `elem` mods -- Duplicate export of M
570 = do { warn_dup_exports <- doptM Opt_WarnDuplicateExports ;
571 warnIf warn_dup_exports (dupModuleExport mod) ;
575 = case lookupModuleEnv imp_env mod of
576 Nothing -> addErr (modExportErr mod) `thenM_`
580 new_exports = filterNameSet (inScopeUnqual rdr_env) names
583 -- This check_occs not only finds conflicts between this item
584 -- and others, but also internally within this item. That is,
585 -- if 'M.x' is in scope in several ways, we'll have several
586 -- members of mod_avails with the same OccName.
587 check_occs ie occs (nameSetToList new_exports) `thenM` \ occs' ->
588 returnM (mod:mods, occs', exports `unionNameSets` new_exports)
590 exports_from_item acc@(mods, occs, exports) ie
591 = lookupGlobalOccRn (ieName ie) `thenM` \ name ->
592 if isUnboundName name then
593 returnM acc -- Avoid error cascade
595 new_exports = filterAvail ie name sub_env
597 checkErr (not (null new_exports)) (exportItemErr ie) `thenM_`
598 checkForDodgyExport ie new_exports `thenM_`
599 check_occs ie occs new_exports `thenM` \ occs' ->
600 returnM (mods, occs', addListToNameSet exports new_exports)
602 -------------------------------
603 filterAvail :: IE RdrName -- Wanted
604 -> Name -- The Name of the ieName of the item
605 -> NameEnv [Name] -- Maps type/class names to their sub-names
606 -> [Name] -- Empty if even one thing reqd is missing
608 filterAvail (IEVar _) n subs = [n]
609 filterAvail (IEThingAbs _) n subs = [n]
610 filterAvail (IEThingAll _) n subs = n : subNames subs n
611 filterAvail (IEThingWith _ rdrs) n subs
612 | any isNothing mb_names = []
613 | otherwise = n : catMaybes mb_names
615 env = mkOccEnv [(nameOccName s, s) | s <- subNames subs n]
616 mb_names = map (lookupOccEnv env . rdrNameOcc) rdrs
618 subNames :: NameEnv [Name] -> Name -> [Name]
619 subNames env n = lookupNameEnv env n `orElse` []
621 mkSubNameEnv :: NameSet -> NameEnv [Name]
622 -- Maps types and classes to their constructors/classops respectively
623 -- This mapping just makes it easier to deal with A(..) export items
625 = foldNameSet add_name emptyNameEnv names
628 | Just parent <- nameParent_maybe name
629 = extendNameEnv_C (\ns _ -> name:ns) env parent [name]
632 -------------------------------
633 inScopeUnqual :: GlobalRdrEnv -> Name -> Bool
634 -- Checks whether the Name is in scope unqualified,
635 -- regardless of whether it's ambiguous or not
636 inScopeUnqual env n = any unQualOK (lookupGRE_Name env n)
638 -------------------------------
639 checkForDodgyExport :: IE RdrName -> [Name] -> RnM ()
640 checkForDodgyExport ie@(IEThingAll tc) [n]
641 | isTcOcc (nameOccName n) = addWarn (dodgyExportWarn tc)
642 -- This occurs when you export T(..), but
643 -- only import T abstractly, or T is a synonym.
644 -- The single [n] is the type or class itself
645 | otherwise = addErr (exportItemErr ie)
646 -- This happes if you export x(..), which is bogus
647 checkForDodgyExport _ _ = return ()
649 -------------------------------
650 check_occs :: IE RdrName -> ExportOccMap -> [Name] -> RnM ExportOccMap
651 check_occs ie occs names
652 = foldlM check occs names
655 = case lookupOccEnv occs name_occ of
656 Nothing -> returnM (extendOccEnv occs name_occ (name, ie))
659 | name == name' -- Duplicate export
660 -> do { warn_dup_exports <- doptM Opt_WarnDuplicateExports ;
661 warnIf warn_dup_exports (dupExportWarn name_occ ie ie') ;
664 | otherwise -- Same occ name but different names: an error
665 -> do { global_env <- getGlobalRdrEnv ;
666 addErr (exportClashErr global_env name name' ie ie') ;
669 name_occ = nameOccName name
672 %*********************************************************
676 %*********************************************************
679 reportDeprecations :: TcGblEnv -> RnM ()
680 reportDeprecations tcg_env
681 = ifOptM Opt_WarnDeprecations $
682 do { (eps,hpt) <- getEpsAndHpt
683 ; mapM_ (check hpt (eps_PIT eps)) all_gres }
685 used_names = findUses (tcg_dus tcg_env) emptyNameSet
686 all_gres = globalRdrEnvElts (tcg_rdr_env tcg_env)
688 check hpt pit (GRE {gre_name = name, gre_prov = Imported (imp_spec:_) _})
689 | name `elemNameSet` used_names
690 , Just deprec_txt <- lookupDeprec hpt pit name
691 = setSrcSpan (is_loc imp_spec) $
692 addWarn (sep [ptext SLIT("Deprecated use of") <+>
693 occNameFlavour (nameOccName name) <+>
698 name_mod = nameModule name
699 imp_mod = is_mod imp_spec
700 imp_msg = ptext SLIT("imported from") <+> ppr imp_mod <> extra
701 extra | imp_mod == name_mod = empty
702 | otherwise = ptext SLIT(", but defined in") <+> ppr name_mod
704 check hpt pit ok_gre = returnM () -- Local, or not used, or not deprectated
705 -- The Imported pattern-match: don't deprecate locally defined names
706 -- For a start, we may be exporting a deprecated thing
707 -- Also we may use a deprecated thing in the defn of another
708 -- deprecated things. We may even use a deprecated thing in
709 -- the defn of a non-deprecated thing, when changing a module's
712 lookupDeprec :: HomePackageTable -> PackageIfaceTable
713 -> Name -> Maybe DeprecTxt
714 lookupDeprec hpt pit n
715 = case lookupIface hpt pit (nameModule n) of
716 Just iface -> mi_dep_fn iface n `seqMaybe` -- Bleat if the thing, *or
717 mi_dep_fn iface (nameParent n) -- its parent*, is deprec'd
719 | isWiredInName n -> Nothing
720 -- We have not necessarily loaded the .hi file for a
721 -- wired-in name (yet), although we *could*.
722 -- And we never deprecate them
724 | otherwise -> pprPanic "lookupDeprec" (ppr n)
725 -- By now all the interfaces should have been loaded
727 gre_is_used :: NameSet -> GlobalRdrElt -> Bool
728 gre_is_used used_names gre = gre_name gre `elemNameSet` used_names
731 %*********************************************************
735 %*********************************************************
738 reportUnusedNames :: Maybe [Located (IE RdrName)] -- Export list
739 -> TcGblEnv -> RnM ()
740 reportUnusedNames export_decls gbl_env
741 = do { 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)
763 = partition (gre_is_used all_used_names) defined_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
791 -- BUG WARNING: this does not deal properly with qualified imports!
792 minimal_imports :: FiniteMap Module AvailEnv
793 minimal_imports0 = foldr add_expall emptyFM expall_mods
794 minimal_imports1 = foldr add_name minimal_imports0 defined_and_used
795 minimal_imports = foldr add_inst_mod minimal_imports1 direct_import_mods
796 -- The last line makes sure that we retain all direct imports
797 -- even if we import nothing explicitly.
798 -- It's not necessarily redundant to import such modules. Consider
802 -- The import M() is not *necessarily* redundant, even if
803 -- we suck in no instance decls from M (e.g. it contains
804 -- no instance decls, or This contains no code). It may be
805 -- that we import M solely to ensure that M's orphan instance
806 -- decls (or those in its imports) are visible to people who
807 -- import This. Sigh.
808 -- There's really no good way to detect this, so the error message
809 -- in RnEnv.warnUnusedModules is weakened instead
811 -- We've carefully preserved the provenance so that we can
812 -- construct minimal imports that import the name by (one of)
813 -- the same route(s) as the programmer originally did.
814 add_name (GRE {gre_name = n, gre_prov = Imported imp_specs _}) acc
815 = addToFM_C plusAvailEnv acc (is_mod (head imp_specs))
816 (unitAvailEnv (mk_avail n (nameParent_maybe n)))
820 -- Modules mentioned as 'module M' in the export list
821 expall_mods = case export_decls of
823 Just es -> [m | L _ (IEModuleContents m) <- es]
825 -- This is really bogus. The idea is that if we see 'module M' in
826 -- the export list we must retain the import decls that drive it
827 -- If we aren't careful we might see
828 -- module A( module M ) where
831 -- and suppose that N exports everything that M does. Then we
832 -- must not drop the import of M even though N brings it all into
835 -- BUG WARNING: 'module M' exports aside, what if M.x is mentioned?!
837 -- The reason that add_expall is bogus is that it doesn't take
838 -- qualified imports into account. But it's an improvement.
839 add_expall mod acc = addToFM_C plusAvailEnv acc mod emptyAvailEnv
841 -- n is the name of the thing, p is the name of its parent
842 mk_avail n (Just p) = AvailTC p [p,n]
843 mk_avail n Nothing | isTcOcc (nameOccName n) = AvailTC n [n]
844 | otherwise = Avail n
846 add_inst_mod (mod,_,_) acc
847 | mod `elemFM` acc = acc -- We import something already
848 | otherwise = addToFM acc mod emptyAvailEnv
850 -- Add an empty collection of imports for a module
851 -- from which we have sucked only instance decls
853 imports = tcg_imports gbl_env
855 direct_import_mods :: [(Module, Maybe Bool, SrcSpan)]
856 -- See the type of the imp_mods for this triple
857 direct_import_mods = moduleEnvElts (imp_mods imports)
859 -- unused_imp_mods are the directly-imported modules
860 -- that are not mentioned in minimal_imports1
861 -- [Note: not 'minimal_imports', because that includes directly-imported
862 -- modules even if we use nothing from them; see notes above]
864 -- BUG WARNING: does not deal correctly with multiple imports of the same module
865 -- becuase direct_import_mods has only one entry per module
866 unused_imp_mods = [(mod,loc) | (mod,imp,loc) <- direct_import_mods,
867 not (mod `elemFM` minimal_imports1),
870 -- The Just False part is not to complain about
871 -- import M (), which is an idiom for importing
872 -- instance declarations
874 module_unused :: Module -> Bool
875 module_unused mod = any (((==) mod) . fst) unused_imp_mods
877 ---------------------
878 warnDuplicateImports :: [GlobalRdrElt] -> RnM ()
879 warnDuplicateImports gres
880 = ifOptM Opt_WarnUnusedImports (mapM_ warn gres)
882 warn (GRE { gre_name = name, gre_prov = Imported imps _ })
883 = addWarn ((quotes (ppr name) <+> ptext SLIT("is imported more than once:"))
884 $$ nest 2 (vcat (map ppr imps)))
887 -- ToDo: deal with original imports with 'qualified' and 'as M' clauses
888 printMinimalImports :: FiniteMap Module AvailEnv -- Minimal imports
890 printMinimalImports imps
891 = ifOptM Opt_D_dump_minimal_imports $ do {
893 mod_ies <- mappM to_ies (fmToList imps) ;
894 this_mod <- getModule ;
895 rdr_env <- getGlobalRdrEnv ;
896 ioToTcRn (do { h <- openFile (mkFilename this_mod) WriteMode ;
897 printForUser h (unQualInScope rdr_env)
898 (vcat (map ppr_mod_ie mod_ies)) })
901 mkFilename this_mod = moduleUserString this_mod ++ ".imports"
902 ppr_mod_ie (mod_name, ies)
903 | mod_name == pRELUDE
905 | null ies -- Nothing except instances comes from here
906 = ptext SLIT("import") <+> ppr mod_name <> ptext SLIT("() -- Instances only")
908 = ptext SLIT("import") <+> ppr mod_name <>
909 parens (fsep (punctuate comma (map ppr ies)))
911 to_ies (mod, avail_env) = mappM to_ie (availEnvElts avail_env) `thenM` \ ies ->
914 to_ie :: AvailInfo -> RnM (IE Name)
915 -- The main trick here is that if we're importing all the constructors
916 -- we want to say "T(..)", but if we're importing only a subset we want
917 -- to say "T(A,B,C)". So we have to find out what the module exports.
918 to_ie (Avail n) = returnM (IEVar n)
919 to_ie (AvailTC n [m]) = ASSERT( n==m )
920 returnM (IEThingAbs n)
922 = loadSrcInterface doc n_mod False `thenM` \ iface ->
923 case [xs | (m,as) <- mi_exports iface,
926 x == nameOccName n] of
927 [xs] | all_used xs -> returnM (IEThingAll n)
928 | otherwise -> returnM (IEThingWith n (filter (/= n) ns))
929 other -> pprTrace "to_ie" (ppr n <+> ppr n_mod <+> ppr other) $
932 all_used avail_occs = all (`elem` map nameOccName ns) avail_occs
933 doc = text "Compute minimal imports from" <+> ppr n
938 %************************************************************************
942 %************************************************************************
945 badImportItemErr iface imp_spec ie
946 = sep [ptext SLIT("Module"), quotes (ppr (is_mod imp_spec)), source_import,
947 ptext SLIT("does not export"), quotes (ppr ie)]
949 source_import | mi_boot iface = ptext SLIT("(hi-boot interface)")
952 dodgyImportWarn item = dodgyMsg (ptext SLIT("import")) item
953 dodgyExportWarn item = dodgyMsg (ptext SLIT("export")) item
956 = sep [ ptext SLIT("The") <+> kind <+> ptext SLIT("item") <+> quotes (ppr (IEThingAll tc)),
957 ptext SLIT("suggests that") <+> quotes (ppr tc) <+> ptext SLIT("has constructor or class methods"),
958 ptext SLIT("but it has none; it is a type synonym or abstract type or class") ]
961 = hsep [ ptext SLIT("Unknown module in export list: module"), quotes (ppr mod)]
963 exportItemErr export_item
964 = sep [ ptext SLIT("The export item") <+> quotes (ppr export_item),
965 ptext SLIT("attempts to export constructors or class methods that are not visible here") ]
967 exportClashErr global_env name1 name2 ie1 ie2
968 = vcat [ ptext SLIT("Conflicting exports for") <+> quotes (ppr occ) <> colon
969 , ppr_export ie1 name1
970 , ppr_export ie2 name2 ]
972 occ = nameOccName name1
973 ppr_export ie name = nest 2 (quotes (ppr ie) <+> ptext SLIT("exports") <+>
974 quotes (ppr name) <+> pprNameProvenance (get_gre name))
976 -- get_gre finds a GRE for the Name, so that we can show its provenance
978 = case lookupGRE_Name global_env name of
980 [] -> pprPanic "exportClashErr" (ppr name)
982 addDupDeclErr :: [Name] -> TcRn ()
985 vcat [ptext SLIT("Multiple declarations of") <+> quotes (ppr name1),
986 ptext SLIT("Declared at:") <+> vcat (map ppr sorted_locs)]
988 locs = map nameSrcLoc names
989 big_loc = foldr1 combineSrcSpans (map srcLocSpan locs)
991 sorted_locs = sortLe (<=) (sortLe (<=) locs)
993 dupExportWarn occ_name ie1 ie2
994 = hsep [quotes (ppr occ_name),
995 ptext SLIT("is exported by"), quotes (ppr ie1),
996 ptext SLIT("and"), quotes (ppr ie2)]
999 = hsep [ptext SLIT("Duplicate"),
1000 quotes (ptext SLIT("Module") <+> ppr mod),
1001 ptext SLIT("in export list")]
1003 moduleDeprec mod txt
1004 = sep [ ptext SLIT("Module") <+> quotes (ppr mod) <+> ptext SLIT("is deprecated:"),