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,
12 #include "HsVersions.h"
14 import {-# SOURCE #-} RnHiFiles ( loadInterface )
16 import CmdLineOpts ( DynFlag(..) )
18 import HsSyn ( HsDecl(..), IE(..), ieName, ImportDecl(..),
19 ForeignDecl(..), HsGroup(..),
20 collectLocatedHsBinders, tyClDeclNames
22 import RdrHsSyn ( RdrNameIE, RdrNameImportDecl, RdrNameHsDecl )
27 import PrelNames ( pRELUDE_Name, mAIN_Name, isBuiltInSyntaxName )
28 import Module ( Module, ModuleName, moduleName,
30 unitModuleEnvByName, lookupModuleEnvByName,
32 import Name ( Name, nameSrcLoc, nameOccName, nameModule )
35 import OccName ( OccName, dataName, isTcOcc )
36 import HscTypes ( Provenance(..), ImportReason(..), GlobalRdrEnv,
37 GenAvailInfo(..), AvailInfo, Avails, IsBootInterface,
38 availName, availNames, availsToNameSet,
39 Deprecations(..), ModIface(..),
40 GlobalRdrElt(..), unQualInScope, isLocalGRE
42 import RdrName ( RdrName, rdrNameOcc, setRdrNameSpace,
43 emptyRdrEnv, foldRdrEnv, isQual )
45 import Maybes ( maybeToBool, catMaybes )
46 import ListSetOps ( removeDups )
47 import Util ( sortLt, notNull )
48 import List ( partition )
49 import IO ( openFile, IOMode(..) )
54 %************************************************************************
58 %************************************************************************
61 rnImports :: [RdrNameImportDecl]
62 -> TcRn m (GlobalRdrEnv, ImportAvails)
65 = -- PROCESS IMPORT DECLS
66 -- Do the non {- SOURCE -} ones first, so that we get a helpful
67 -- warning for {- SOURCE -} ones that are unnecessary
68 getModule `thenM` \ this_mod ->
69 getSrcLocM `thenM` \ loc ->
70 doptM Opt_NoImplicitPrelude `thenM` \ opt_no_prelude ->
72 all_imports = mk_prel_imports this_mod loc opt_no_prelude ++ imports
73 (source, ordinary) = partition is_source_import all_imports
74 is_source_import (ImportDecl _ is_boot _ _ _ _) = is_boot
76 get_imports = importsFromImportDecl (moduleName this_mod)
78 mappM get_imports ordinary `thenM` \ stuff1 ->
79 mappM get_imports source `thenM` \ stuff2 ->
83 (imp_gbl_envs, imp_avails) = unzip (stuff1 ++ stuff2)
84 gbl_env :: GlobalRdrEnv
85 gbl_env = foldr plusGlobalRdrEnv emptyRdrEnv imp_gbl_envs
87 all_avails :: ImportAvails
88 all_avails = foldr plusImportAvails emptyImportAvails imp_avails
91 returnM (gbl_env, all_avails)
93 -- NB: opt_NoImplicitPrelude is slightly different to import Prelude ();
94 -- because the former doesn't even look at Prelude.hi for instance
95 -- declarations, whereas the latter does.
96 mk_prel_imports this_mod loc no_prelude
97 | moduleName this_mod == pRELUDE_Name
98 || explicit_prelude_import
102 | otherwise = [preludeImportDecl loc]
104 explicit_prelude_import
105 = notNull [ () | (ImportDecl mod _ _ _ _ _) <- imports,
106 mod == pRELUDE_Name ]
108 preludeImportDecl loc
109 = ImportDecl pRELUDE_Name
110 False {- Not a boot interface -}
111 False {- Not qualified -}
112 Nothing {- No "as" -}
113 Nothing {- No import list -}
118 importsFromImportDecl :: ModuleName
120 -> TcRn m (GlobalRdrEnv, ImportAvails)
122 importsFromImportDecl this_mod_name
123 (ImportDecl imp_mod_name is_boot qual_only as_mod import_spec iloc)
126 doc = ppr imp_mod_name <+> ptext SLIT("is directly imported")
129 -- If there's an error in loadInterface, (e.g. interface
130 -- file not found) we get lots of spurious errors from 'filterImports'
131 tryM (loadInterface doc imp_mod_name (ImportByUser is_boot)) `thenM` \ mb_iface ->
134 Left exn -> returnM (emptyRdrEnv, emptyImportAvails ) ;
138 imp_mod = mi_module iface
139 avails_by_module = mi_exports iface
140 deprecs = mi_deprecs iface
141 dir_imp = unitModuleEnvByName imp_mod_name (imp_mod, import_all import_spec)
144 avails = [ avail | (mod_name, avails) <- avails_by_module,
145 mod_name /= this_mod_name,
147 -- If the module exports anything defined in this module, just ignore it.
148 -- Reason: otherwise it looks as if there are two local definition sites
149 -- for the thing, and an error gets reported. Easiest thing is just to
150 -- filter them out up front. This situation only arises if a module
151 -- imports itself, or another module that imported it. (Necessarily,
152 -- this invoves a loop.)
154 -- Tiresome consequence: if you say
159 -- module B( AType ) where
160 -- import {-# SOURCE #-} A( AType )
162 -- then you'll get a 'B does not export AType' message. Oh well.
165 -- Complain if we import a deprecated module
166 ifOptM Opt_WarnDeprecations (
168 DeprecAll txt -> addWarn (moduleDeprec imp_mod_name txt)
172 -- Filter the imports according to the import list
173 filterImports imp_mod_name is_boot import_spec avails `thenM` \ (filtered_avails, explicits) ->
176 unqual_imp = not qual_only -- Maybe want unqualified names
177 qual_mod = case as_mod of
178 Nothing -> imp_mod_name
179 Just another_name -> another_name
181 mk_prov name = NonLocalDef (UserImport imp_mod iloc (name `elemNameSet` explicits))
182 gbl_env = mkGlobalRdrEnv qual_mod unqual_imp mk_prov filtered_avails deprecs
183 imports = mkImportAvails qual_mod unqual_imp gbl_env filtered_avails
185 returnM (gbl_env, imports { imp_mods = dir_imp})
188 import_all (Just (False, _)) = False -- Imports are spec'd explicitly
189 import_all other = True -- Everything is imported
193 %************************************************************************
195 importsFromLocalDecls
197 %************************************************************************
199 From the top-level declarations of this module produce
200 * the lexical environment
202 created by its bindings.
204 Complain about duplicate bindings
207 importsFromLocalDecls :: HsGroup RdrName
208 -> TcRn m (GlobalRdrEnv, ImportAvails)
209 importsFromLocalDecls group
210 = getModule `thenM` \ this_mod ->
211 getLocalDeclBinders this_mod group `thenM` \ avails ->
212 -- The avails that are returned don't include the "system" names
214 all_names :: [Name] -- All the defns; no dups eliminated
215 all_names = [name | avail <- avails, name <- availNames avail]
218 (_, dups) = removeDups compare all_names
220 -- Check for duplicate definitions
221 -- The complaint will come out as "Multiple declarations of Foo.f" because
222 -- since 'f' is in the env twice, the unQualInScope used by the error-msg
223 -- printer returns False. It seems awkward to fix, unfortunately.
224 mappM_ (addErr . dupDeclErr) dups `thenM_`
226 doptM Opt_NoImplicitPrelude `thenM` \ implicit_prelude ->
228 mod_name = moduleName this_mod
229 unqual_imp = True -- Want unqualified names
230 mk_prov n = LocalDef -- Provenance is local
232 gbl_env = mkGlobalRdrEnv mod_name unqual_imp mk_prov avails NoDeprecs
233 -- NoDeprecs: don't complain about locally defined names
234 -- For a start, we may be exporting a deprecated thing
235 -- Also we may use a deprecated thing in the defn of another
236 -- deprecated things. We may even use a deprecated thing in
237 -- the defn of a non-deprecated thing, when changing a module's
241 -- Optimisation: filter out names for built-in syntax
242 -- They just clutter up the environment (esp tuples), and the parser
243 -- will generate Exact RdrNames for them, so the cluttered
244 -- envt is no use. To avoid doing this filter all the type,
245 -- we use -fno-implicit-prelude as a clue that the filter is
246 -- worth while. Really, it's only useful for Base and Tuple.
248 -- It's worth doing because it makes the environment smaller for
249 -- every module that imports the Prelude
251 -- Note: don't filter the gbl_env (hence avails, not avails' in
252 -- defn of gbl_env above). Stupid reason: when parsing
253 -- data type decls, the constructors start as Exact tycon-names,
254 -- and then get turned into data con names by zapping the name space;
255 -- but that stops them being Exact, so they get looked up. Sigh.
256 -- It doesn't matter because it only affects the Data.Tuple really.
257 -- The important thing is to trim down the exports.
258 imports = mkImportAvails mod_name unqual_imp gbl_env avails'
259 avails' | implicit_prelude = filter not_built_in_syntax avails
261 not_built_in_syntax a = not (all isBuiltInSyntaxName (availNames a))
262 -- Only filter it if all the names of the avail are built-in
263 -- In particular, lists have (:) which is not built in syntax
264 -- so we don't filter it out.
266 returnM (gbl_env, imports)
270 %*********************************************************
272 \subsection{Getting binders out of a declaration}
274 %*********************************************************
276 @getLocalDeclBinders@ returns the names for a @RdrNameHsDecl@. It's
277 used for both source code (from @importsFromLocalDecls@) and interface
278 files (@loadDecl@ calls @getTyClDeclBinders@).
280 *** See "THE NAMING STORY" in HsDecls ****
283 getLocalDeclBinders :: Module -> HsGroup RdrName -> TcRn m [AvailInfo]
284 getLocalDeclBinders mod (HsGroup {hs_valds = val_decls,
285 hs_tyclds = tycl_decls,
286 hs_fords = foreign_decls })
287 = -- For type and class decls, we generate Global names, with
288 -- no export indicator. They need to be global because they get
289 -- permanently bound into the TyCons and Classes. They don't need
290 -- an export indicator because they are all implicitly exported.
292 mappM new_tc tycl_decls `thenM` \ tc_avails ->
293 mappM new_bndr (for_hs_bndrs ++ val_hs_bndrs) `thenM` \ simple_bndrs ->
295 returnM (tc_avails ++ map Avail simple_bndrs)
297 new_bndr (rdr_name,loc) = newTopBinder mod rdr_name loc
299 val_hs_bndrs = collectLocatedHsBinders val_decls
300 for_hs_bndrs = [(nm,loc) | ForeignImport nm _ _ _ loc <- foreign_decls]
302 new_tc tc_decl = mappM new_bndr (tyClDeclNames tc_decl) `thenM` \ names@(main_name:_) ->
303 returnM (AvailTC main_name names)
307 %************************************************************************
309 \subsection{Filtering imports}
311 %************************************************************************
313 @filterImports@ takes the @ExportEnv@ telling what the imported module makes
314 available, and filters it through the import spec (if any).
317 filterImports :: ModuleName -- The module being imported
318 -> IsBootInterface -- Tells whether it's a {-# SOURCE #-} import
319 -> Maybe (Bool, [RdrNameIE]) -- Import spec; True => hiding
320 -> [AvailInfo] -- What's available
321 -> TcRn m ([AvailInfo], -- What's imported
322 NameSet) -- What was imported explicitly
324 -- Complains if import spec mentions things that the module doesn't export
325 -- Warns/informs if import spec contains duplicates.
326 filterImports mod from Nothing imports
327 = returnM (imports, emptyNameSet)
329 filterImports mod from (Just (want_hiding, import_items)) total_avails
330 = mappM get_item import_items `thenM` \ avails_w_explicits_s ->
332 (item_avails, explicits_s) = unzip (concat avails_w_explicits_s)
333 explicits = foldl addListToNameSet emptyNameSet explicits_s
336 let -- All imported; item_avails to be hidden
337 hidden = availsToNameSet item_avails
338 keep n = not (n `elemNameSet` hidden)
340 returnM (pruneAvails keep total_avails, emptyNameSet)
342 -- Just item_avails imported; nothing to be hidden
343 returnM (item_avails, explicits)
345 import_fm :: FiniteMap OccName AvailInfo
346 import_fm = listToFM [ (nameOccName name, avail)
347 | avail <- total_avails,
348 name <- availNames avail]
349 -- Even though availNames returns data constructors too,
350 -- they won't make any difference because naked entities like T
351 -- in an import list map to TcOccs, not VarOccs.
353 bale_out item = addErr (badImportItemErr mod from item) `thenM_`
356 get_item :: RdrNameIE -> TcRn m [(AvailInfo, [Name])]
357 -- Empty list for a bad item.
358 -- Singleton is typical case.
359 -- Can have two when we are hiding, and mention C which might be
360 -- both a class and a data constructor.
361 -- The [Name] is the list of explicitly-mentioned names
362 get_item item@(IEModuleContents _) = bale_out item
364 get_item item@(IEThingAll _)
365 = case check_item item of
366 Nothing -> bale_out item
367 Just avail@(AvailTC _ [n]) -> -- This occurs when you import T(..), but
368 -- only export T abstractly. The single [n]
369 -- in the AvailTC is the type or class itself
370 ifOptM Opt_WarnMisc (addWarn (dodgyImportWarn mod item)) `thenM_`
371 returnM [(avail, [availName avail])]
372 Just avail -> returnM [(avail, [availName avail])]
374 get_item item@(IEThingAbs n)
375 | want_hiding -- hiding( C )
376 -- Here the 'C' can be a data constructor *or* a type/class
377 = case catMaybes [check_item item, check_item (IEVar data_n)] of
379 avails -> returnM [(a, []) | a <- avails]
380 -- The 'explicits' list is irrelevant when hiding
382 data_n = setRdrNameSpace n dataName
385 = case check_item item of
386 Nothing -> bale_out item
387 Just avail -> returnM [(avail, availNames avail)]
390 | not (maybeToBool maybe_in_import_avails) ||
391 not (maybeToBool maybe_filtered_avail)
395 = Just filtered_avail
398 wanted_occ = rdrNameOcc (ieName item)
399 maybe_in_import_avails = lookupFM import_fm wanted_occ
401 Just avail = maybe_in_import_avails
402 maybe_filtered_avail = filterAvail item avail
403 Just filtered_avail = maybe_filtered_avail
407 filterAvail :: RdrNameIE -- Wanted
408 -> AvailInfo -- Available
409 -> Maybe AvailInfo -- Resulting available;
410 -- Nothing if (any of the) wanted stuff isn't there
412 filterAvail ie@(IEThingWith want wants) avail@(AvailTC n ns)
413 | sub_names_ok = Just (AvailTC n (filter is_wanted ns))
414 | otherwise = Nothing
416 is_wanted name = nameOccName name `elem` wanted_occs
417 sub_names_ok = all (`elem` avail_occs) wanted_occs
418 avail_occs = map nameOccName ns
419 wanted_occs = map rdrNameOcc (want:wants)
421 filterAvail (IEThingAbs _) (AvailTC n ns) = ASSERT( n `elem` ns )
424 filterAvail (IEThingAbs _) avail@(Avail n) = Just avail -- Type synonyms
426 filterAvail (IEVar _) avail@(Avail n) = Just avail
427 filterAvail (IEVar v) avail@(AvailTC n ns) = Just (AvailTC n (filter wanted ns))
429 wanted n = nameOccName n == occ
431 -- The second equation happens if we import a class op, thus
433 -- where op is a class operation
435 filterAvail (IEThingAll _) avail@(AvailTC _ _) = Just avail
436 -- We don't complain even if the IE says T(..), but
437 -- no constrs/class ops of T are available
438 -- Instead that's caught with a warning by the caller
440 filterAvail ie avail = Nothing
444 %************************************************************************
446 \subsection{Export list processing}
448 %************************************************************************
450 Processing the export list.
452 You might think that we should record things that appear in the export
453 list as ``occurrences'' (using @addOccurrenceName@), but you'd be
454 wrong. We do check (here) that they are in scope, but there is no
455 need to slurp in their actual declaration (which is what
456 @addOccurrenceName@ forces).
458 Indeed, doing so would big trouble when compiling @PrelBase@, because
459 it re-exports @GHC@, which includes @takeMVar#@, whose type includes
460 @ConcBase.StateAndSynchVar#@, and so on...
463 type ExportAccum -- The type of the accumulating parameter of
464 -- the main worker function in exportsFromAvail
465 = ([ModuleName], -- 'module M's seen so far
466 ExportOccMap, -- Tracks exported occurrence names
467 AvailEnv) -- The accumulated exported stuff, kept in an env
468 -- so we can common-up related AvailInfos
469 emptyExportAccum = ([], emptyFM, emptyAvailEnv)
471 type ExportOccMap = FiniteMap OccName (Name, RdrNameIE)
472 -- Tracks what a particular exported OccName
473 -- in an export list refers to, and which item
474 -- it came from. It's illegal to export two distinct things
475 -- that have the same occurrence name
478 exportsFromAvail :: Maybe [RdrNameIE] -> TcRn m Avails
479 -- Complains if two distinct exports have same OccName
480 -- Warns about identical exports.
481 -- Complains about exports items not in scope
482 exportsFromAvail Nothing
483 = do { this_mod <- getModule ;
484 if moduleName this_mod == mAIN_Name then
486 -- Export nothing; Main.$main is automatically exported
488 exportsFromAvail (Just [IEModuleContents (moduleName this_mod)])
489 -- but for all other modules export everything.
492 exportsFromAvail (Just exports)
493 = do { TcGblEnv { tcg_imports = imports } <- getGblEnv ;
494 warn_dup_exports <- doptM Opt_WarnDuplicateExports ;
495 exports_from_avail exports warn_dup_exports imports }
497 exports_from_avail export_items warn_dup_exports
498 (ImportAvails { imp_unqual = mod_avail_env,
499 imp_env = entity_avail_env })
500 = foldlM exports_from_item emptyExportAccum
501 export_items `thenM` \ (_, _, export_avail_map) ->
502 returnM (nameEnvElts export_avail_map)
505 exports_from_item :: ExportAccum -> RdrNameIE -> TcRn m ExportAccum
507 exports_from_item acc@(mods, occs, avails) ie@(IEModuleContents mod)
508 | mod `elem` mods -- Duplicate export of M
509 = warnIf warn_dup_exports (dupModuleExport mod) `thenM_`
513 = case lookupModuleEnvByName mod_avail_env mod of
514 Nothing -> addErr (modExportErr mod) `thenM_`
517 -> foldlM (check_occs warn_dup_exports ie)
518 occs mod_avails `thenM` \ occs' ->
520 avails' = foldl addAvail avails mod_avails
522 returnM (mod:mods, occs', avails')
524 exports_from_item acc@(mods, occs, avails) ie
525 = lookupGRE (ieName ie) `thenM` \ mb_gre ->
527 Nothing -> addErr (unknownNameErr (ieName ie)) `thenM_`
531 -- Get the AvailInfo for the parent of the specified name
532 case lookupAvailEnv entity_avail_env (gre_parent gre) of {
533 Nothing -> pprPanic "exportsFromAvail"
534 ((ppr (ieName ie)) <+> ppr gre) ;
537 -- Filter out the bits we want
538 case filterAvail ie avail of {
539 Nothing -> -- Not enough availability
540 addErr (exportItemErr ie) `thenM_`
545 -- Phew! It's OK! Now to check the occurrence stuff!
546 warnIf (not (ok_item ie avail)) (dodgyExportWarn ie) `thenM_`
547 check_occs warn_dup_exports ie occs export_avail `thenM` \ occs' ->
548 returnM (mods, occs', addAvail avails export_avail)
553 ok_item (IEThingAll _) (AvailTC _ [n]) = False
554 -- This occurs when you import T(..), but
555 -- only export T abstractly. The single [n]
556 -- in the AvailTC is the type or class itself
559 check_occs :: Bool -> RdrNameIE -> ExportOccMap -> AvailInfo -> TcRn m ExportOccMap
560 check_occs warn_dup_exports ie occs avail
561 = foldlM check occs (availNames avail)
564 = case lookupFM occs name_occ of
565 Nothing -> returnM (addToFM occs name_occ (name, ie))
567 | name == name' -> -- Duplicate export
568 warnIf warn_dup_exports
569 (dupExportWarn name_occ ie ie')
570 `thenM_` returnM occs
572 | otherwise -> -- Same occ name but different names: an error
573 addErr (exportClashErr name_occ ie ie') `thenM_`
576 name_occ = nameOccName name
579 %*********************************************************
581 \subsection{Unused names}
583 %*********************************************************
586 reportUnusedNames :: TcGblEnv
587 -> NameSet -- Used in this module
589 reportUnusedNames gbl_env used_names
590 = warnUnusedModules unused_imp_mods `thenM_`
591 warnUnusedTopBinds bad_locals `thenM_`
592 warnUnusedImports bad_imports `thenM_`
593 printMinimalImports minimal_imports
595 direct_import_mods :: [ModuleName]
596 direct_import_mods = map (moduleName . fst)
597 (moduleEnvElts (imp_mods (tcg_imports gbl_env)))
599 -- Now, a use of C implies a use of T,
600 -- if C was brought into scope by T(..) or T(C)
601 really_used_names :: NameSet
602 really_used_names = used_names `unionNameSets`
603 mkNameSet [ gre_parent gre
604 | gre <- defined_names,
605 gre_name gre `elemNameSet` used_names]
607 -- Collect the defined names from the in-scope environment
608 -- Look for the qualified ones only, else get duplicates
609 defined_names :: [GlobalRdrElt]
610 defined_names = foldRdrEnv add [] (tcg_rdr_env gbl_env)
611 add rdr_name ns acc | isQual rdr_name = ns ++ acc
614 defined_and_used, defined_but_not_used :: [GlobalRdrElt]
615 (defined_and_used, defined_but_not_used) = partition used defined_names
616 used gre = gre_name gre `elemNameSet` really_used_names
618 -- Filter out the ones only defined implicitly
619 bad_locals :: [GlobalRdrElt]
620 bad_locals = filter isLocalGRE defined_but_not_used
622 bad_imports :: [GlobalRdrElt]
623 bad_imports = filter bad_imp defined_but_not_used
624 bad_imp (GRE {gre_prov = NonLocalDef (UserImport mod _ True)}) = not (module_unused mod)
625 bad_imp other = False
627 -- To figure out the minimal set of imports, start with the things
628 -- that are in scope (i.e. in gbl_env). Then just combine them
629 -- into a bunch of avails, so they are properly grouped
630 minimal_imports :: FiniteMap ModuleName AvailEnv
631 minimal_imports0 = emptyFM
632 minimal_imports1 = foldr add_name minimal_imports0 defined_and_used
633 minimal_imports = foldr add_inst_mod minimal_imports1 direct_import_mods
634 -- The last line makes sure that we retain all direct imports
635 -- even if we import nothing explicitly.
636 -- It's not necessarily redundant to import such modules. Consider
640 -- The import M() is not *necessarily* redundant, even if
641 -- we suck in no instance decls from M (e.g. it contains
642 -- no instance decls, or This contains no code). It may be
643 -- that we import M solely to ensure that M's orphan instance
644 -- decls (or those in its imports) are visible to people who
645 -- import This. Sigh.
646 -- There's really no good way to detect this, so the error message
647 -- in RnEnv.warnUnusedModules is weakened instead
650 -- We've carefully preserved the provenance so that we can
651 -- construct minimal imports that import the name by (one of)
652 -- the same route(s) as the programmer originally did.
653 add_name (GRE {gre_name = n, gre_parent = p,
654 gre_prov = NonLocalDef (UserImport m _ _)}) acc
655 = addToFM_C plusAvailEnv acc (moduleName m)
656 (unitAvailEnv (mk_avail n p))
660 -- n is the name of the thing, p is the name of its parent
661 mk_avail n p | n/=p = AvailTC p [p,n]
662 | isTcOcc (nameOccName p) = AvailTC n [n]
663 | otherwise = Avail n
666 | m `elemFM` acc = acc -- We import something already
667 | otherwise = addToFM acc m emptyAvailEnv
668 -- Add an empty collection of imports for a module
669 -- from which we have sucked only instance decls
671 -- unused_imp_mods are the directly-imported modules
672 -- that are not mentioned in minimal_imports1
673 -- [Note: not 'minimal_imports', because that includes direcly-imported
674 -- modules even if we use nothing from them; see notes above]
675 unused_imp_mods = [m | m <- direct_import_mods,
676 not (maybeToBool (lookupFM minimal_imports1 m)),
679 module_unused :: Module -> Bool
680 module_unused mod = moduleName mod `elem` unused_imp_mods
683 -- ToDo: deal with original imports with 'qualified' and 'as M' clauses
684 printMinimalImports :: FiniteMap ModuleName AvailEnv -- Minimal imports
686 printMinimalImports imps
687 = ifOptM Opt_D_dump_minimal_imports $ do {
689 mod_ies <- mappM to_ies (fmToList imps) ;
690 this_mod <- getModule ;
691 rdr_env <- getGlobalRdrEnv ;
692 ioToTcRn (do { h <- openFile (mkFilename this_mod) WriteMode ;
693 printForUser h (unQualInScope rdr_env)
694 (vcat (map ppr_mod_ie mod_ies)) })
697 mkFilename this_mod = moduleNameUserString (moduleName this_mod) ++ ".imports"
698 ppr_mod_ie (mod_name, ies)
699 | mod_name == pRELUDE_Name
701 | null ies -- Nothing except instances comes from here
702 = ptext SLIT("import") <+> ppr mod_name <> ptext SLIT("() -- Instances only")
704 = ptext SLIT("import") <+> ppr mod_name <>
705 parens (fsep (punctuate comma (map ppr ies)))
707 to_ies (mod, avail_env) = mappM to_ie (availEnvElts avail_env) `thenM` \ ies ->
710 to_ie :: AvailInfo -> TcRn m (IE Name)
711 -- The main trick here is that if we're importing all the constructors
712 -- we want to say "T(..)", but if we're importing only a subset we want
713 -- to say "T(A,B,C)". So we have to find out what the module exports.
714 to_ie (Avail n) = returnM (IEVar n)
715 to_ie (AvailTC n [m]) = ASSERT( n==m )
716 returnM (IEThingAbs n)
718 = loadInterface (text "Compute minimal imports from" <+> ppr n_mod)
719 n_mod ImportBySystem `thenM` \ iface ->
720 case [xs | (m,as) <- mi_exports iface,
724 [xs] | all (`elem` ns) xs -> returnM (IEThingAll n)
725 | otherwise -> returnM (IEThingWith n (filter (/= n) ns))
726 other -> pprTrace "to_ie" (ppr n <+> ppr (nameModule n) <+> ppr other) $
729 n_mod = moduleName (nameModule n)
733 %************************************************************************
737 %************************************************************************
740 badImportItemErr mod from ie
741 = sep [ptext SLIT("Module"), quotes (ppr mod), source_import,
742 ptext SLIT("does not export"), quotes (ppr ie)]
744 source_import = case from of
745 True -> ptext SLIT("(hi-boot interface)")
748 dodgyImportWarn mod item = dodgyMsg (ptext SLIT("import")) item
749 dodgyExportWarn item = dodgyMsg (ptext SLIT("export")) item
751 dodgyMsg kind item@(IEThingAll tc)
752 = sep [ ptext SLIT("The") <+> kind <+> ptext SLIT("item") <+> quotes (ppr item),
753 ptext SLIT("suggests that") <+> quotes (ppr tc) <+> ptext SLIT("has constructor or class methods"),
754 ptext SLIT("but it has none; it is a type synonym or abstract type or class") ]
757 = hsep [ ptext SLIT("Unknown module in export list: module"), quotes (ppr mod)]
759 exportItemErr export_item
760 = sep [ ptext SLIT("The export item") <+> quotes (ppr export_item),
761 ptext SLIT("attempts to export constructors or class methods that are not visible here") ]
763 exportClashErr occ_name ie1 ie2
764 = hsep [ptext SLIT("The export items"), quotes (ppr ie1)
765 ,ptext SLIT("and"), quotes (ppr ie2)
766 ,ptext SLIT("create conflicting exports for"), quotes (ppr occ_name)]
769 = vcat [ptext SLIT("Multiple declarations of") <+> quotes (ppr n),
770 nest 4 (vcat (map ppr sorted_locs))]
772 sorted_locs = sortLt occ'ed_before (map nameSrcLoc (n:ns))
773 occ'ed_before a b = LT == compare a b
775 dupExportWarn occ_name ie1 ie2
776 = hsep [quotes (ppr occ_name),
777 ptext SLIT("is exported by"), quotes (ppr ie1),
778 ptext SLIT("and"), quotes (ppr ie2)]
781 = hsep [ptext SLIT("Duplicate"),
782 quotes (ptext SLIT("Module") <+> ppr mod),
783 ptext SLIT("in export list")]
786 = sep [ ptext SLIT("Module") <+> quotes (ppr mod) <+> ptext SLIT("is deprecated:"),