2 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1996
4 \section[RnNames]{Extracting imported and top-level names in scope}
11 #include "HsVersions.h"
13 import CmdLineOpts ( opt_NoImplicitPrelude, opt_WarnDuplicateExports,
17 import HsSyn ( HsModule(..), ImportDecl(..), HsDecl(..),
19 ForeignDecl(..), ExtName(..),
23 import RdrHsSyn ( RdrNameHsDecl, RdrName(..), RdrNameIE, RdrNameImportDecl,
24 RdrNameHsModule, RdrNameFixityDecl,
27 import RnIfaces ( getInterfaceExports, getDeclBinders, recordSlurp, checkUpToDate )
28 import BasicTypes ( IfaceFlavour(..) )
34 import UniqFM ( UniqFM, addListToUFM_C, lookupUFM )
35 import Bag ( Bag, bagToList )
36 import Maybes ( maybeToBool )
39 import Util ( removeDups )
44 %************************************************************************
46 \subsection{Get global names}
48 %************************************************************************
51 getGlobalNames :: RdrNameHsModule
52 -> RnMG (Maybe (ExportEnv,
54 FiniteMap Name HowInScope, -- Locally defined or explicitly imported
55 Name -> PrintUnqualified))
56 -- Nothing => no need to recompile
58 getGlobalNames m@(HsModule this_mod _ exports imports _ _ mod_loc)
59 = fixRn (\ ~(rec_exp_fn, _) ->
61 -- PROCESS LOCAL DECLS
62 -- Do these *first* so that the correct provenance gets
63 -- into the global name cache.
64 importsFromLocalDecls rec_exp_fn m `thenRn` \ (local_rn_env, local_mod_avails, local_info) ->
66 -- PROCESS IMPORT DECLS
67 mapAndUnzip3Rn importsFromImportDecl all_imports
68 `thenRn` \ (imp_rn_envs, imp_avails_s, explicit_imports_s) ->
71 -- We put the local env second, so that a local provenance
72 -- "wins", even if a module imports itself.
73 foldlRn plusRnEnv emptyRnEnv imp_rn_envs `thenRn` \ imp_rn_env ->
74 plusRnEnv imp_rn_env local_rn_env `thenRn` \ rn_env ->
77 -- We can't go for an early exit before this because we have to check
78 -- for name clashes. Consider:
80 -- module A where module B where
84 -- Suppose I've compiled everything up, and then I add a
85 -- new definition to module B, that defines "f".
87 -- Then I must detect the name clash in A before going for an early
88 -- exit. The early-exit code checks what's actually needed from B
89 -- to compile A, and of course that doesn't include B.f. That's
90 -- why we wait till after the plusRnEnv stuff to do the early-exit.
91 checkEarlyExit this_mod `thenRn` \ up_to_date ->
93 returnRn (error "early exit", Nothing)
97 -- PROCESS EXPORT LISTS
99 export_avails :: ExportAvails
100 export_avails = foldr plusExportAvails local_mod_avails imp_avails_s
102 explicit_info :: FiniteMap Name HowInScope -- Locally defined or explicitly imported
103 explicit_info = foldr plusFM local_info explicit_imports_s
105 exportsFromAvail this_mod exports export_avails rn_env
106 `thenRn` \ (export_fn, export_env) ->
108 -- BUILD THE "IMPORT FN". It just tells whether a name is in
109 -- scope in an unqualified form.
111 print_unqual = mkImportFn imp_rn_env
114 returnRn (export_fn, Just (export_env, rn_env, explicit_info, print_unqual))
115 ) `thenRn` \ (_, result) ->
118 junk_exp_fn = error "RnNames:export_fn"
120 all_imports = prel_imports ++ imports
122 -- NB: opt_NoImplicitPrelude is slightly different to import Prelude ();
123 -- because the former doesn't even look at Prelude.hi for instance declarations,
124 -- whereas the latter does.
125 prel_imports | this_mod == pRELUDE ||
126 explicit_prelude_import ||
127 opt_NoImplicitPrelude
130 | otherwise = [ImportDecl pRELUDE
131 False {- Not qualified -}
132 HiFile {- Not source imported -}
133 Nothing {- No "as" -}
134 Nothing {- No import list -}
137 explicit_prelude_import
138 = not (null [ () | (ImportDecl mod qual _ _ _ _) <- imports, mod == pRELUDE ])
143 = checkErrsRn `thenRn` \ no_errs_so_far ->
144 if not no_errs_so_far then
145 -- Found errors already, so exit now
149 traceRn (text "Considering whether compilation is required...") `thenRn_`
150 if not opt_SourceUnchanged then
151 -- Source code changed and no errors yet... carry on
152 traceRn (nest 4 (text "source file changed or recompilation check turned off")) `thenRn_`
156 -- Unchanged source, and no errors yet; see if usage info
157 -- up to date, and exit if so
158 checkUpToDate mod `thenRn` \ up_to_date ->
159 putDocRn (text "Compilation" <+>
160 text (if up_to_date then "IS NOT" else "IS") <+>
161 text "required") `thenRn_`
166 importsFromImportDecl :: RdrNameImportDecl
169 FiniteMap Name HowInScope) -- Records the explicitly-imported things
171 importsFromImportDecl (ImportDecl mod qual_only as_source as_mod import_spec loc)
173 getInterfaceExports mod as_source `thenRn` \ (avails, fixities) ->
174 filterImports mod import_spec avails `thenRn` \ (filtered_avails, hides, explicits) ->
176 how_in_scope = FromImportDecl mod loc
177 explicit_info = listToFM [(name, how_in_scope)
178 | avail <- explicits,
179 name <- availNames avail
183 True -- Want qualified names
184 (not qual_only) -- Maybe want unqualified names
187 filtered_avails (\n -> how_in_scope)
188 [ (occ,(fixity,how_in_scope)) | (occ,fixity) <- fixities ]
189 `thenRn` \ (rn_env, mod_avails) ->
190 returnRn (rn_env, mod_avails, explicit_info)
195 importsFromLocalDecls rec_exp_fn (HsModule mod _ _ _ fix_decls decls _)
196 = foldlRn getLocalDeclBinders [] decls `thenRn` \ avails ->
198 -- Record that locally-defined things are available
199 mapRn (recordSlurp Nothing Compulsory) avails `thenRn_`
202 mapRn fixityFromFixDecl fix_decls `thenRn` \ fixities ->
204 -- Record where the available stuff came from
206 explicit_info = listToFM [(name, FromLocalDefn (getSrcLoc name))
208 name <- availNames avail
212 False -- Don't want qualified names
213 True -- Want unqualified names
214 Nothing -- No "as M" part
216 avails (\n -> FromLocalDefn (getSrcLoc n))
218 `thenRn` \ (rn_env, mod_avails) ->
219 returnRn (rn_env, mod_avails, explicit_info)
221 newLocalName rdr_name loc
222 = newLocallyDefinedGlobalName mod (rdrNameOcc rdr_name) rec_exp_fn loc
224 getLocalDeclBinders avails (ValD binds)
225 = mapRn do_one (bagToList (collectTopBinders binds)) `thenRn` \ val_avails ->
226 returnRn (val_avails ++ avails)
228 -- foreign import declaration
229 getLocalDeclBinders avails (ForD (ForeignDecl nm (Just _) _ _ _ loc))
230 = do_one (nm,loc) `thenRn` \ for_avail ->
231 returnRn (for_avail : avails)
233 -- foreign export dynamic declaration
234 getLocalDeclBinders avails (ForD (ForeignDecl nm Nothing _ Dynamic _ loc))
235 = do_one (nm,loc) `thenRn` \ for_avail ->
236 returnRn (for_avail : avails)
238 getLocalDeclBinders avails decl
239 = getDeclBinders newLocalName decl `thenRn` \ avail ->
241 NotAvailable -> returnRn avails -- Instance decls and suchlike
242 other -> returnRn (avail : avails)
244 do_one (rdr_name, loc)
245 = newLocalName rdr_name loc `thenRn` \ name ->
246 returnRn (Avail name)
249 %************************************************************************
251 \subsection{Filtering imports}
253 %************************************************************************
255 @filterImports@ takes the @ExportEnv@ telling what the imported module makes
256 available, and filters it through the import spec (if any).
259 filterImports :: Module
260 -> Maybe (Bool, [RdrNameIE]) -- Import spec; True => hidin
261 -> [AvailInfo] -- What's available
262 -> RnMG ([AvailInfo], -- What's actually imported
263 [AvailInfo], -- What's to be hidden (the unqualified version, that is)
264 [AvailInfo]) -- What was imported explicitly
266 -- Complains if import spec mentions things that the module doesn't export
267 -- Warns/informs if import spec contains duplicates.
268 filterImports mod Nothing imports
269 = returnRn (imports, [], [])
271 filterImports mod (Just (want_hiding, import_items)) avails
272 = mapRn check_item import_items `thenRn` \ item_avails ->
275 returnRn (avails, item_avails, []) -- All imported; item_avails to be hidden
277 returnRn (item_avails, [], item_avails) -- Just item_avails imported; nothing to be hidden
280 import_fm :: FiniteMap OccName AvailInfo
281 import_fm = listToFM [ (nameOccName name, avail)
283 name <- availEntityNames avail]
285 check_item item@(IEModuleContents _)
286 = addErrRn (badImportItemErr mod item) `thenRn_`
287 returnRn NotAvailable
290 | not (maybeToBool maybe_in_import_avails) ||
291 (case filtered_avail of { NotAvailable -> True; other -> False })
292 = addErrRn (badImportItemErr mod item) `thenRn_`
293 returnRn NotAvailable
295 | dodgy_import = addWarnRn (dodgyImportWarn mod item) `thenRn_`
296 returnRn filtered_avail
298 | otherwise = returnRn filtered_avail
301 maybe_in_import_avails = lookupFM import_fm (ieOcc item)
302 Just avail = maybe_in_import_avails
303 filtered_avail = filterAvail item avail
304 dodgy_import = case (item, avail) of
305 (IEThingAll _, AvailTC _ [n]) -> True
306 -- This occurs when you import T(..), but
307 -- only export T abstractly. The single [n]
308 -- in the AvailTC is the type or class itself
316 %************************************************************************
318 \subsection{Qualifiying imports}
320 %************************************************************************
322 @qualifyImports@ takes the @ExportEnv@ after filtering through the import spec
323 of an import decl, and deals with producing an @RnEnv@ with the
324 right qualified names. It also turns the @Names@ in the @ExportEnv@ into
325 fully fledged @Names@.
328 qualifyImports :: Module -- Imported module
329 -> Bool -- True <=> want qualified import
330 -> Bool -- True <=> want unqualified import
331 -> Maybe Module -- Optional "as M" part
332 -> [AvailInfo] -- What's to be hidden
333 -> Avails -> (Name -> HowInScope) -- Whats imported and how
334 -> [(OccName, (Fixity, HowInScope))] -- Ditto for fixities
335 -> RnMG (RnEnv, ExportAvails)
337 qualifyImports this_mod qual_imp unqual_imp as_mod hides
338 avails name_to_his fixities
340 -- Make the name environment. Even though we're talking about a
341 -- single import module there might still be name clashes,
342 -- because it might be the module being compiled.
343 foldlRn add_avail emptyGlobalNameEnv avails `thenRn` \ name_env1 ->
345 -- Delete things that are hidden
346 name_env2 = foldl del_avail name_env1 hides
348 -- Create the fixity env
349 fixity_env = foldl (add_fixity name_env2) emptyFixityEnv fixities
351 -- Create the export-availability info
352 export_avails = mkExportAvails qual_mod unqual_imp name_env2 avails
354 returnRn (RnEnv name_env2 fixity_env, export_avails)
356 qual_mod = case as_mod of
358 Just another_name -> another_name
360 add_avail :: GlobalNameEnv -> AvailInfo -> RnMG GlobalNameEnv
361 add_avail env avail = foldlRn add_name env (availNames avail)
363 add_name env name = add qual_imp env (Qual qual_mod occ err_hif) `thenRn` \ env1 ->
364 add unqual_imp env1 (Unqual occ)
366 add False env rdr_name = returnRn env
367 add True env rdr_name = addOneToGlobalNameEnv env rdr_name (name, name_to_his name)
368 occ = nameOccName name
370 del_avail env avail = foldl delOneFromGlobalNameEnv env rdr_names
372 rdr_names = map (Unqual . nameOccName) (availNames avail)
374 add_fixity name_env fix_env (occ_name, fixity)
375 = add qual $ add unqual $ fix_env
377 qual = Qual qual_mod occ_name err_hif
378 unqual = Unqual occ_name
380 add rdr_name fix_env | maybeToBool (lookupFM name_env rdr_name)
381 = addOneToFixityEnv fix_env rdr_name fixity
385 err_hif = error "qualifyImports: hif" -- Not needed in key to mapping
388 unQualify adds an Unqual binding for every existing Qual binding.
391 unQualify :: FiniteMap RdrName elt -> FiniteMap RdrName elt
392 unQualify fm = addListToFM fm [(Unqual occ, elt) | (Qual _ occ _, elt) <- fmToList fm]
395 %************************************************************************
397 \subsection{Local declarations}
399 %************************************************************************
403 fixityFromFixDecl :: RdrNameFixityDecl -> RnMG (OccName, (Fixity, HowInScope))
405 fixityFromFixDecl (FixityDecl rdr_name fixity loc)
406 = returnRn (rdrNameOcc rdr_name, (fixity, FromLocalDefn loc))
410 %************************************************************************
412 \subsection{Export list processing
414 %************************************************************************
416 The @AvailEnv@ type is just used internally in @exportsFromAvail@.
417 When exporting we need to combine the availabilities for a particular
418 exported thing, and we also need to check for name clashes -- that
419 is: two exported things must have different @OccNames@.
422 type AvailEnv = FiniteMap OccName (RdrNameIE, AvailInfo, Int{-no. of clashes-})
423 -- The FM maps each OccName to the RdrNameIE that gave rise to it,
424 -- for error reporting, as well as to its AvailInfo
426 emptyAvailEnv = emptyFM
429 Add new entry to environment. Checks for name clashes, i.e.,
430 plain duplicates or exported entity pairs that have different OccNames.
431 (c.f. 5.1.1 of Haskell 1.4 report.)
433 addAvailEnv :: Bool -> RdrNameIE -> AvailEnv -> AvailInfo -> RnM s d AvailEnv
434 addAvailEnv warn_dups ie env NotAvailable = returnRn env
435 addAvailEnv warn_dups ie env (AvailTC _ []) = returnRn env
436 addAvailEnv warn_dups ie env avail
437 | warn_dups = mapMaybeRn (addErrRn . availClashErr) () conflict `thenRn_`
438 returnRn (addToFM_C addAvail env key elt)
439 | otherwise = returnRn (addToFM_C addAvail env key elt)
441 occ_avail = nameOccName (availName avail)
444 | not warn_dups || occ_ie == occ_avail = occ_avail
446 -- export item is a class method, use export occ name instead.
447 -- (this is only needed to get more precise warnings about
449 elt = (ie,avail,reports_on)
452 | maybeToBool dup = 1
455 conflict = conflictFM bad_avail env key elt
457 | warn_dups = conflictFM dup_avail env key elt
458 | otherwise = Nothing
460 addListToAvailEnv :: AvailEnv -> RdrNameIE -> [AvailInfo] -> RnM s d AvailEnv
461 addListToAvailEnv env ie items
462 = foldlRn (addAvailEnv False{-don't warn about dups-} ie) env items
464 bad_avail (ie1,avail1,r1) (ie2,avail2,r2)
465 = availName avail1 /= availName avail2 -- Same OccName, different Name
466 dup_avail (ie1,avail1,r1) (ie2,avail2,r2)
467 = availName avail1 == availName avail2 -- Same OccName & avail.
469 addAvail (ie1,a1,r1) (ie2,a2,r2) = (ie1, a1 `plusAvail` a2, r1 + r2)
472 Processing the export list.
474 You might think that we should record things that appear in the export list as
475 ``occurrences'' (using addOccurrenceName), but you'd be wrong. We do check (here)
476 that they are in scope, but there is no need to slurp in their actual declaration
477 (which is what addOccurrenceName forces). Indeed, doing so would big trouble when
478 compiling PrelBase, because it re-exports GHC, which includes takeMVar#, whose type
479 includes ConcBase.StateAndSynchVar#, and so on...
482 exportsFromAvail :: Module
483 -> Maybe [RdrNameIE] -- Export spec
486 -> RnMG (Name -> ExportFlag, ExportEnv)
487 -- Complains if two distinct exports have same OccName
488 -- Warns about identical exports.
489 -- Complains about exports items not in scope
490 exportsFromAvail this_mod Nothing export_avails rn_env
491 = exportsFromAvail this_mod (Just [IEModuleContents this_mod]) export_avails rn_env
493 exportsFromAvail this_mod (Just export_items)
494 (mod_avail_env, entity_avail_env)
495 (RnEnv global_name_env fixity_env)
496 = checkForModuleExportDups export_items `thenRn` \ export_items' ->
497 foldlRn exports_from_item emptyAvailEnv export_items' `thenRn` \ export_avail_env ->
499 dup_entries = fmToList (filterFM (\ _ (_,_,clashes) -> clashes > 0) export_avail_env)
501 mapRn (addWarnRn . dupExportWarn) dup_entries `thenRn_`
503 export_avails = map (\ (_,a,_) -> a) (eltsFM export_avail_env)
504 export_fixities = mk_exported_fixities (availsToNameSet export_avails)
505 export_fn = mk_export_fn export_avails
507 returnRn (export_fn, ExportEnv export_avails export_fixities)
510 exports_from_item :: AvailEnv -> RdrNameIE -> RnMG AvailEnv
511 exports_from_item export_avail_env ie@(IEModuleContents mod)
512 = case lookupFM mod_avail_env mod of
513 Nothing -> failWithRn export_avail_env (modExportErr mod)
514 Just avails -> addListToAvailEnv export_avail_env ie avails
516 exports_from_item export_avail_env ie
517 | not (maybeToBool maybe_in_scope)
518 = failWithRn export_avail_env (unknownNameErr (ieName ie))
521 -- I can't see why this should ever happen; if the thing is in scope
522 -- at all it ought to have some availability
523 | not (maybeToBool maybe_avail)
524 = pprTrace "exportsFromAvail: curious Nothing:" (ppr name)
525 returnRn export_avail_env
529 = failWithRn export_avail_env (exportItemErr ie export_avail)
531 | otherwise -- Phew! It's OK!
532 = addAvailEnv opt_WarnDuplicateExports ie export_avail_env export_avail
534 maybe_in_scope = lookupFM global_name_env (ieName ie)
535 Just (name,_) = maybe_in_scope
536 maybe_avail = lookupUFM entity_avail_env name
537 Just avail = maybe_avail
538 export_avail = filterAvail ie avail
539 enough_avail = case export_avail of {NotAvailable -> False; other -> True}
541 -- We export a fixity iff we export a thing with the same (qualified) RdrName
542 mk_exported_fixities :: NameSet -> [(OccName, Fixity)]
543 mk_exported_fixities exports
544 = fmToList (foldr (perhaps_add_fixity exports)
546 (fmToList fixity_env))
548 perhaps_add_fixity :: NameSet -> (RdrName, (Fixity, HowInScope))
549 -> FiniteMap OccName Fixity
550 -> FiniteMap OccName Fixity
551 perhaps_add_fixity exports (rdr_name, (fixity, how_in_scope)) fix_env
553 do_nothing = fix_env -- The default is to pass on the env unchanged
555 -- Step 1: check whether the rdr_name is in scope; if so find its Name
556 case lookupFM global_name_env rdr_name of {
557 Nothing -> do_nothing;
558 Just (fixity_name,_) ->
560 -- Step 2: check whether the fixity thing is exported
561 if not (fixity_name `elemNameSet` exports) then
565 -- Step 3: check whether we already have a fixity for the
566 -- Name's OccName in the fix_env we are building up. This can easily
567 -- happen. the original fixity_env might contain bindings for
568 -- M.a and N.a, if a was imported via M and N.
569 -- If this does happen, we expect the fixity to be the same either way.
571 occ_name = rdrNameOcc rdr_name
573 case lookupFM fix_env occ_name of {
574 Just fixity1 -> -- Got it already
575 ASSERT( fixity == fixity1 )
579 -- Step 3: add it to the outgoing fix_env
580 addToFM fix_env occ_name fixity
583 {- warn and weed out duplicate module entries from export list. -}
584 checkForModuleExportDups :: [RdrNameIE] -> RnMG [RdrNameIE]
585 checkForModuleExportDups ls
586 | opt_WarnDuplicateExports = check_modules ls
587 | otherwise = returnRn ls
589 -- NOTE: reorders the export list by moving all module-contents
590 -- exports to the end (removing duplicates in the process.)
594 ls -> mapRn (\ ds@(IEModuleContents x:_) ->
595 addWarnRn (dupModuleExport x (length ds))) ls `thenRn_`
596 returnRn ()) `thenRn_`
597 returnRn (ls_no_modules ++ no_module_dups)
599 (ls_no_modules,modules) = foldr split_mods ([],[]) ls
601 split_mods i@(IEModuleContents _) (no_ms,ms) = (no_ms,i:ms)
602 split_mods i (no_ms,ms) = (i:no_ms,ms)
604 (no_module_dups, dups) = removeDups cmp_mods modules
606 cmp_mods (IEModuleContents m1) (IEModuleContents m2) = m1 `compare` m2
608 mk_export_fn :: [AvailInfo] -> (Name -> ExportFlag)
610 = \name -> if name `elemNameSet` exported_names
614 exported_names :: NameSet
615 exported_names = availsToNameSet avails
618 %************************************************************************
622 %************************************************************************
625 badImportItemErr mod ie
626 = sep [ptext SLIT("Module"), quotes (pprModule mod),
627 ptext SLIT("does not export"), quotes (ppr ie)]
629 dodgyImportWarn mod (IEThingAll tc)
630 = sep [ptext SLIT("Module") <+> quotes (pprModule mod) <+> ptext SLIT("exports") <+> quotes (ppr tc),
631 ptext SLIT("with no constructors/class operations;"),
632 ptext SLIT("yet it is imported with a (..)")]
635 = hsep [ ptext SLIT("Unknown module in export list: module"), quotes (pprModule mod)]
637 exportItemErr export_item NotAvailable
638 = sep [ ptext SLIT("Export item not in scope:"), quotes (ppr export_item)]
640 exportItemErr export_item avail
641 = hang (ptext SLIT("Export item not fully in scope:"))
642 4 (vcat [hsep [ptext SLIT("Wanted: "), ppr export_item],
643 hsep [ptext SLIT("Available:"), ppr (ieOcc export_item), pprAvail avail]])
645 availClashErr (occ_name, ((ie1,avail1,_), (ie2,avail2,_)))
646 = hsep [ptext SLIT("The export items"), quotes (ppr ie1), ptext SLIT("and"), quotes (ppr ie2),
647 ptext SLIT("create conflicting exports for"), quotes (ppr occ_name)]
649 dupExportWarn (occ_name, (_,_,times))
650 = hsep [quotes (ppr occ_name),
651 ptext SLIT("mentioned"), speakNTimes (times+1),
652 ptext SLIT("in export list")]
654 dupModuleExport mod times
655 = hsep [ptext SLIT("Module"), quotes (pprModule mod),
656 ptext SLIT("mentioned"), speakNTimes times,
657 ptext SLIT("in export list")]