2 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
4 \section[RnNames]{Extracting imported and top-level names in scope}
11 #include "HsVersions.h"
13 import CmdLineOpts ( opt_NoImplicitPrelude, opt_WarnDuplicateExports,
14 opt_SourceUnchanged, opt_WarnUnusedBinds
17 import HsSyn ( HsModule(..), HsDecl(..), TyClDecl(..),
19 ForeignDecl(..), ForKind(..), isDynamic,
20 FixitySig(..), Sig(..), ImportDecl(..),
23 import RdrHsSyn ( RdrNameIE, RdrNameImportDecl,
24 RdrNameHsModule, RdrNameHsDecl
26 import RnIfaces ( getInterfaceExports, getDeclBinders, getDeclSysBinders,
27 recordSlurp, checkUpToDate
34 import PrelInfo ( main_RDR )
35 import UniqFM ( lookupUFM )
36 import Bag ( bagToList )
37 import Maybes ( maybeToBool )
38 import Module ( ModuleName, mkThisModule, pprModuleName, WhereFrom(..) )
40 import Name ( Name, ExportFlag(..), ImportReason(..), Provenance(..),
41 isLocallyDefined, setNameProvenance,
42 nameOccName, getSrcLoc, pprProvenance, getNameProvenance
44 import RdrName ( RdrName, rdrNameOcc, mkRdrQual, mkRdrUnqual, isQual )
45 import SrcLoc ( SrcLoc )
46 import NameSet ( elemNameSet, emptyNameSet )
48 import Unique ( getUnique )
49 import Util ( removeDups, equivClassesByUniq, sortLt )
50 import List ( partition )
55 %************************************************************************
57 \subsection{Get global names}
59 %************************************************************************
62 getGlobalNames :: RdrNameHsModule
63 -> RnMG (Maybe (ExportEnv,
65 FixityEnv, -- Fixities for local decls only
66 NameEnv AvailInfo -- Maps a name to its parent AvailInfo
67 -- Just for in-scope things only
69 -- Nothing => no need to recompile
71 getGlobalNames (HsModule this_mod _ exports imports decls mod_loc)
72 = -- These two fix-loops are to get the right
73 -- provenance information into a Name
74 fixRn (\ ~(rec_gbl_env, rec_exported_avails, _) ->
77 rec_unqual_fn :: Name -> Bool -- Is this chap in scope unqualified?
78 rec_unqual_fn = unQualInScope rec_gbl_env
80 rec_exp_fn :: Name -> ExportFlag
81 rec_exp_fn = mk_export_fn (availsToNameSet rec_exported_avails)
83 setModuleRn this_mod $
85 -- PROCESS LOCAL DECLS
86 -- Do these *first* so that the correct provenance gets
87 -- into the global name cache.
88 importsFromLocalDecls this_mod rec_exp_fn decls
89 `thenRn` \ (local_gbl_env, local_mod_avails) ->
91 -- PROCESS IMPORT DECLS
92 -- Do the non {- SOURCE -} ones first, so that we get a helpful
93 -- warning for {- SOURCE -} ones that are unnecessary
95 (source, ordinary) = partition is_source_import all_imports
96 is_source_import (ImportDecl _ ImportByUserSource _ _ _ _) = True
97 is_source_import other = False
99 mapAndUnzipRn (importsFromImportDecl rec_unqual_fn) ordinary
100 `thenRn` \ (imp_gbl_envs1, imp_avails_s1) ->
101 mapAndUnzipRn (importsFromImportDecl rec_unqual_fn) source
102 `thenRn` \ (imp_gbl_envs2, imp_avails_s2) ->
105 -- We put the local env second, so that a local provenance
106 -- "wins", even if a module imports itself.
108 gbl_env :: GlobalRdrEnv
109 imp_gbl_env = foldr plusGlobalRdrEnv emptyRdrEnv (imp_gbl_envs2 ++ imp_gbl_envs1)
110 gbl_env = imp_gbl_env `plusGlobalRdrEnv` local_gbl_env
112 all_avails :: ExportAvails
113 all_avails = foldr plusExportAvails local_mod_avails (imp_avails_s2 ++ imp_avails_s1)
116 -- TRY FOR EARLY EXIT
117 -- We can't go for an early exit before this because we have to check
118 -- for name clashes. Consider:
120 -- module A where module B where
124 -- Suppose I've compiled everything up, and then I add a
125 -- new definition to module B, that defines "f".
127 -- Then I must detect the name clash in A before going for an early
128 -- exit. The early-exit code checks what's actually needed from B
129 -- to compile A, and of course that doesn't include B.f. That's
130 -- why we wait till after the plusEnv stuff to do the early-exit.
131 checkEarlyExit this_mod `thenRn` \ up_to_date ->
133 returnRn (gbl_env, junk_exp_fn, Nothing)
136 -- RECORD BETTER PROVENANCES IN THE CACHE
137 -- The names in the envirnoment have better provenances (e.g. imported on line x)
138 -- than the names in the name cache. We update the latter now, so that we
139 -- we start renaming declarations we'll get the good names
140 -- The isQual is because the qualified name is always in scope
141 updateProvenances (concat [names | (rdr_name, names) <- rdrEnvToList imp_gbl_env,
142 isQual rdr_name]) `thenRn_`
144 -- PROCESS EXPORT LISTS
145 exportsFromAvail this_mod exports all_avails gbl_env
146 `thenRn` \ exported_avails ->
149 returnRn (gbl_env, exported_avails, Just all_avails)
150 ) `thenRn` \ (gbl_env, exported_avails, maybe_stuff) ->
152 case maybe_stuff of {
153 Nothing -> returnRn Nothing ;
156 -- DEAL WITH FIXITIES
157 fixitiesFromLocalDecls gbl_env decls `thenRn` \ local_fixity_env ->
159 -- Export only those fixities that are for names that are
160 -- (a) defined in this module
162 exported_fixities :: [(Name,Fixity)]
163 exported_fixities = [(name,fixity)
164 | FixitySig name fixity _ <- nameEnvElts local_fixity_env,
165 isLocallyDefined name
168 traceRn (text "fixity env" <+> vcat (map ppr (nameEnvElts local_fixity_env))) `thenRn_`
172 export_env = ExportEnv exported_avails exported_fixities
173 (_, global_avail_env) = all_avails
175 returnRn (Just (export_env, gbl_env, local_fixity_env, global_avail_env))
178 junk_exp_fn = error "RnNames:export_fn"
180 all_imports = prel_imports ++ imports
182 -- NB: opt_NoImplicitPrelude is slightly different to import Prelude ();
183 -- because the former doesn't even look at Prelude.hi for instance declarations,
184 -- whereas the latter does.
185 prel_imports | this_mod == pRELUDE_Name ||
186 explicit_prelude_import ||
187 opt_NoImplicitPrelude
190 | otherwise = [ImportDecl pRELUDE_Name
192 False {- Not qualified -}
193 Nothing {- No "as" -}
194 Nothing {- No import list -}
197 explicit_prelude_import
198 = not (null [ () | (ImportDecl mod _ _ _ _ _) <- imports, mod == pRELUDE_Name ])
203 = checkErrsRn `thenRn` \ no_errs_so_far ->
204 if not no_errs_so_far then
205 -- Found errors already, so exit now
209 traceRn (text "Considering whether compilation is required...") `thenRn_`
210 if not opt_SourceUnchanged then
211 -- Source code changed and no errors yet... carry on
212 traceRn (nest 4 (text "source file changed or recompilation check turned off")) `thenRn_`
216 -- Unchanged source, and no errors yet; see if usage info
217 -- up to date, and exit if so
218 checkUpToDate mod `thenRn` \ up_to_date ->
219 putDocRn (text "Compilation" <+>
220 text (if up_to_date then "IS NOT" else "IS") <+>
221 text "required") `thenRn_`
226 importsFromImportDecl :: (Name -> Bool) -- OK to omit qualifier
228 -> RnMG (GlobalRdrEnv,
231 importsFromImportDecl is_unqual (ImportDecl imp_mod_name from qual_only as_mod import_spec iloc)
232 = pushSrcLocRn iloc $
233 getInterfaceExports imp_mod_name from `thenRn` \ (imp_mod, avails) ->
236 -- If there's an error in getInterfaceExports, (e.g. interface
237 -- file not found) we get lots of spurious errors from 'filterImports'
238 returnRn (emptyRdrEnv, mkEmptyExportAvails imp_mod_name)
241 filterImports imp_mod_name import_spec avails
242 `thenRn` \ (filtered_avails, hides, explicits) ->
244 -- We 'improve' the provenance by setting
245 -- (a) the import-reason field, so that the Name says how it came into scope
246 -- including whether it's explicitly imported
247 -- (b) the print-unqualified field
248 -- But don't fiddle with wired-in things or we get in a twist
251 setNameProvenance name (NonLocalDef (UserImport imp_mod iloc (is_explicit name))
253 is_explicit name = name `elemNameSet` explicits
255 qualifyImports imp_mod_name
256 (not qual_only) -- Maybe want unqualified names
258 filtered_avails improve_prov
259 `thenRn` \ (rdr_name_env, mod_avails) ->
261 returnRn (rdr_name_env, mod_avails)
266 importsFromLocalDecls mod_name rec_exp_fn decls
267 = mapRn (getLocalDeclBinders newLocalName) decls `thenRn` \ avails_s ->
270 avails = concat avails_s
272 all_names :: [Name] -- All the defns; no dups eliminated
273 all_names = [name | avail <- avails, name <- availNames avail]
276 dups = filter non_singleton (equivClassesByUniq getUnique all_names)
278 non_singleton (x1:x2:xs) = True
279 non_singleton other = False
281 -- Check for duplicate definitions
282 mapRn_ (addErrRn . dupDeclErr) dups `thenRn_`
284 -- Record that locally-defined things are available
285 mapRn_ (recordSlurp Nothing) avails `thenRn_`
287 -- Build the environment
288 qualifyImports mod_name
289 True -- Want unqualified names
296 newLocalName rdr_name loc = newLocalTopBinder mod (rdrNameOcc rdr_name)
298 mod = mkThisModule mod_name
300 getLocalDeclBinders :: (RdrName -> SrcLoc -> RnMG Name) -- New-name function
303 getLocalDeclBinders new_name (ValD binds)
304 = mapRn do_one (bagToList (collectTopBinders binds))
306 do_one (rdr_name, loc) = new_name rdr_name loc `thenRn` \ name ->
307 returnRn (Avail name)
309 getLocalDeclBinders new_name decl
310 = getDeclBinders new_name decl `thenRn` \ maybe_avail ->
312 Nothing -> returnRn [] -- Instance decls and suchlike
313 Just avail -> getDeclSysBinders new_sys_name decl `thenRn_`
316 -- The getDeclSysBinders is just to get the names of superclass selectors
317 -- etc, into the cache
318 new_sys_name rdr_name loc = newImplicitBinder (rdrNameOcc rdr_name) loc
320 fixitiesFromLocalDecls :: GlobalRdrEnv -> [RdrNameHsDecl] -> RnMG FixityEnv
321 fixitiesFromLocalDecls gbl_env decls
322 = foldlRn getFixities emptyNameEnv decls
324 getFixities :: FixityEnv -> RdrNameHsDecl -> RnMG FixityEnv
325 getFixities acc (FixD fix)
328 getFixities acc (TyClD (ClassDecl _ _ _ sigs _ _ _ _ _ _))
329 = foldlRn fix_decl acc [sig | FixSig sig <- sigs]
330 -- Get fixities from class decl sigs too.
331 getFixities acc other_decl
334 fix_decl acc sig@(FixitySig rdr_name fixity loc)
335 = -- Check for fixity decl for something not declared
336 case lookupRdrEnv gbl_env rdr_name of {
337 Nothing | opt_WarnUnusedBinds
338 -> pushSrcLocRn loc (addWarnRn (unusedFixityDecl rdr_name fixity))
339 `thenRn_` returnRn acc
340 | otherwise -> returnRn acc ;
344 -- Check for duplicate fixity decl
345 case lookupNameEnv acc name of {
346 Just (FixitySig _ _ loc') -> addErrRn (dupFixityDecl rdr_name loc loc')
347 `thenRn_` returnRn acc ;
349 Nothing -> returnRn (addToNameEnv acc name (FixitySig name fixity loc))
353 %************************************************************************
355 \subsection{Filtering imports}
357 %************************************************************************
359 @filterImports@ takes the @ExportEnv@ telling what the imported module makes
360 available, and filters it through the import spec (if any).
363 filterImports :: ModuleName -- The module being imported
364 -> Maybe (Bool, [RdrNameIE]) -- Import spec; True => hiding
365 -> [AvailInfo] -- What's available
366 -> RnMG ([AvailInfo], -- What's actually imported
367 [AvailInfo], -- What's to be hidden
368 -- (the unqualified version, that is)
369 NameSet) -- What was imported explicitly
371 -- Complains if import spec mentions things that the module doesn't export
372 -- Warns/informs if import spec contains duplicates.
373 filterImports mod Nothing imports
374 = returnRn (imports, [], emptyNameSet)
376 filterImports mod (Just (want_hiding, import_items)) avails
377 = mapMaybeRn check_item import_items `thenRn` \ avails_w_explicits ->
379 (item_avails, explicits_s) = unzip avails_w_explicits
380 explicits = foldl addListToNameSet emptyNameSet explicits_s
384 -- All imported; item_avails to be hidden
385 returnRn (avails, item_avails, emptyNameSet)
387 -- Just item_avails imported; nothing to be hidden
388 returnRn (item_avails, [], explicits)
390 import_fm :: FiniteMap OccName AvailInfo
391 import_fm = listToFM [ (nameOccName name, avail)
393 name <- availNames avail]
394 -- Even though availNames returns data constructors too,
395 -- they won't make any difference because naked entities like T
396 -- in an import list map to TcOccs, not VarOccs.
398 check_item item@(IEModuleContents _)
399 = addErrRn (badImportItemErr mod item) `thenRn_`
403 | not (maybeToBool maybe_in_import_avails) ||
404 not (maybeToBool maybe_filtered_avail)
405 = addErrRn (badImportItemErr mod item) `thenRn_`
408 | dodgy_import = addWarnRn (dodgyImportWarn mod item) `thenRn_`
409 returnRn (Just (filtered_avail, explicits))
411 | otherwise = returnRn (Just (filtered_avail, explicits))
414 wanted_occ = rdrNameOcc (ieName item)
415 maybe_in_import_avails = lookupFM import_fm wanted_occ
417 Just avail = maybe_in_import_avails
418 maybe_filtered_avail = filterAvail item avail
419 Just filtered_avail = maybe_filtered_avail
420 explicits | dot_dot = [availName filtered_avail]
421 | otherwise = availNames filtered_avail
423 dot_dot = case item of
427 dodgy_import = case (item, avail) of
428 (IEThingAll _, AvailTC _ [n]) -> True
429 -- This occurs when you import T(..), but
430 -- only export T abstractly. The single [n]
431 -- in the AvailTC is the type or class itself
438 %************************************************************************
440 \subsection{Qualifiying imports}
442 %************************************************************************
444 @qualifyImports@ takes the @ExportEnv@ after filtering through the import spec
445 of an import decl, and deals with producing an @RnEnv@ with the
446 right qualified names. It also turns the @Names@ in the @ExportEnv@ into
447 fully fledged @Names@.
450 qualifyImports :: ModuleName -- Imported module
451 -> Bool -- True <=> want unqualified import
452 -> Maybe ModuleName -- Optional "as M" part
453 -> [AvailInfo] -- What's to be hidden
454 -> Avails -- Whats imported and how
455 -> (Name -> Name) -- Improves the provenance on imported things
456 -> RnMG (GlobalRdrEnv, ExportAvails)
457 -- NB: the Names in ExportAvails don't have the improve-provenance
458 -- function applied to them
459 -- We could fix that, but I don't think it matters
461 qualifyImports this_mod unqual_imp as_mod hides
464 -- Make the name environment. We're talking about a
465 -- single module here, so there must be no name clashes.
466 -- In practice there only ever will be if it's the module
469 -- Add the things that are available
470 name_env1 = foldl add_avail emptyRdrEnv avails
472 -- Delete things that are hidden
473 name_env2 = foldl del_avail name_env1 hides
475 -- Create the export-availability info
476 export_avails = mkExportAvails qual_mod unqual_imp name_env2 avails
478 returnRn (name_env2, export_avails)
481 qual_mod = case as_mod of
483 Just another_name -> another_name
485 add_avail :: GlobalRdrEnv -> AvailInfo -> GlobalRdrEnv
486 add_avail env avail = foldl add_name env (availNames avail)
492 env1 = addOneToGlobalRdrEnv env (mkRdrQual qual_mod occ) better_name
493 env2 = addOneToGlobalRdrEnv env1 (mkRdrUnqual occ) better_name
494 occ = nameOccName name
495 better_name = improve_prov name
497 del_avail env avail = foldl delOneFromGlobalRdrEnv env rdr_names
499 rdr_names = map (mkRdrUnqual . nameOccName) (availNames avail)
503 %************************************************************************
505 \subsection{Export list processing}
507 %************************************************************************
509 Processing the export list.
511 You might think that we should record things that appear in the export list
512 as ``occurrences'' (using @addOccurrenceName@), but you'd be wrong.
513 We do check (here) that they are in scope,
514 but there is no need to slurp in their actual declaration
515 (which is what @addOccurrenceName@ forces).
517 Indeed, doing so would big trouble when
518 compiling @PrelBase@, because it re-exports @GHC@, which includes @takeMVar#@,
519 whose type includes @ConcBase.StateAndSynchVar#@, and so on...
522 type ExportAccum -- The type of the accumulating parameter of
523 -- the main worker function in exportsFromAvail
524 = ([ModuleName], -- 'module M's seen so far
525 ExportOccMap, -- Tracks exported occurrence names
526 NameEnv AvailInfo) -- The accumulated exported stuff, kept in an env
527 -- so we can common-up related AvailInfos
529 type ExportOccMap = FiniteMap OccName (Name, RdrNameIE)
530 -- Tracks what a particular exported OccName
531 -- in an export list refers to, and which item
532 -- it came from. It's illegal to export two distinct things
533 -- that have the same occurrence name
536 exportsFromAvail :: ModuleName
537 -> Maybe [RdrNameIE] -- Export spec
541 -- Complains if two distinct exports have same OccName
542 -- Warns about identical exports.
543 -- Complains about exports items not in scope
544 exportsFromAvail this_mod Nothing export_avails global_name_env
545 = exportsFromAvail this_mod true_exports export_avails global_name_env
547 true_exports = Just $ if this_mod == mAIN_Name
548 then [IEVar main_RDR]
549 -- export Main.main *only* unless otherwise specified,
550 else [IEModuleContents this_mod]
551 -- but for all other modules export everything.
553 exportsFromAvail this_mod (Just export_items)
554 (mod_avail_env, entity_avail_env)
556 = foldlRn exports_from_item
557 ([], emptyFM, emptyNameEnv) export_items `thenRn` \ (_, _, export_avail_map) ->
559 export_avails :: [AvailInfo]
560 export_avails = nameEnvElts export_avail_map
562 returnRn export_avails
565 exports_from_item :: ExportAccum -> RdrNameIE -> RnMG ExportAccum
567 exports_from_item acc@(mods, occs, avails) ie@(IEModuleContents mod)
568 | mod `elem` mods -- Duplicate export of M
569 = warnCheckRn opt_WarnDuplicateExports
570 (dupModuleExport mod) `thenRn_`
574 = case lookupFM mod_avail_env mod of
575 Nothing -> failWithRn acc (modExportErr mod)
576 Just mod_avails -> foldlRn (check_occs ie) occs mod_avails
579 avails' = foldl add_avail avails mod_avails
581 returnRn (mod:mods, occs', avails')
583 exports_from_item acc@(mods, occs, avails) ie
584 | not (maybeToBool maybe_in_scope)
585 = failWithRn acc (unknownNameErr (ieName ie))
587 | not (null dup_names)
588 = addNameClashErrRn rdr_name (name:dup_names) `thenRn_`
592 -- I can't see why this should ever happen; if the thing is in scope
593 -- at all it ought to have some availability
594 | not (maybeToBool maybe_avail)
595 = pprTrace "exportsFromAvail: curious Nothing:" (ppr name)
600 = failWithRn acc (exportItemErr ie)
602 | otherwise -- Phew! It's OK! Now to check the occurrence stuff!
603 = check_occs ie occs export_avail `thenRn` \ occs' ->
604 returnRn (mods, occs', add_avail avails export_avail)
608 maybe_in_scope = lookupFM global_name_env rdr_name
609 Just (name:dup_names) = maybe_in_scope
610 maybe_avail = lookupUFM entity_avail_env name
611 Just avail = maybe_avail
612 maybe_export_avail = filterAvail ie avail
613 enough_avail = maybeToBool maybe_export_avail
614 Just export_avail = maybe_export_avail
616 add_avail avails avail = addToNameEnv_C plusAvail avails (availName avail) avail
618 check_occs :: RdrNameIE -> ExportOccMap -> AvailInfo -> RnMG ExportOccMap
619 check_occs ie occs avail
620 = foldlRn check occs (availNames avail)
623 = case lookupFM occs name_occ of
624 Nothing -> returnRn (addToFM occs name_occ (name, ie))
626 | name == name' -> -- Duplicate export
627 warnCheckRn opt_WarnDuplicateExports
628 (dupExportWarn name_occ ie ie')
629 `thenRn_` returnRn occs
631 | otherwise -> -- Same occ name but different names: an error
632 failWithRn occs (exportClashErr name_occ ie ie')
634 name_occ = nameOccName name
636 mk_export_fn :: NameSet -> (Name -> ExportFlag)
637 mk_export_fn exported_names
638 = \name -> if name `elemNameSet` exported_names
643 %************************************************************************
647 %************************************************************************
650 badImportItemErr mod ie
651 = sep [ptext SLIT("Module"), quotes (pprModuleName mod),
652 ptext SLIT("does not export"), quotes (ppr ie)]
654 dodgyImportWarn mod (IEThingAll tc)
655 = sep [ptext SLIT("Module") <+> quotes (pprModuleName mod)
656 <+> ptext SLIT("exports") <+> quotes (ppr tc),
657 ptext SLIT("with no constructors/class operations;"),
658 ptext SLIT("yet it is imported with a (..)")]
661 = hsep [ ptext SLIT("Unknown module in export list: module"), quotes (pprModuleName mod)]
663 exportItemErr export_item
664 = sep [ ptext SLIT("Bad export item"), quotes (ppr export_item)]
666 exportClashErr occ_name ie1 ie2
667 = hsep [ptext SLIT("The export items"), quotes (ppr ie1)
668 ,ptext SLIT("and"), quotes (ppr ie2)
669 ,ptext SLIT("create conflicting exports for"), quotes (ppr occ_name)]
672 = vcat [ptext SLIT("Multiple declarations of") <+> quotes (ppr n),
673 nest 4 (vcat (map pp sorted_ns))]
675 sorted_ns = sortLt occ'ed_before (n:ns)
677 occ'ed_before a b = LT == compare (getSrcLoc a) (getSrcLoc b)
679 pp n = pprProvenance (getNameProvenance n)
681 dupExportWarn occ_name ie1 ie2
682 = hsep [quotes (ppr occ_name),
683 ptext SLIT("is exported by"), quotes (ppr ie1),
684 ptext SLIT("and"), quotes (ppr ie2)]
687 = hsep [ptext SLIT("Duplicate"),
688 quotes (ptext SLIT("Module") <+> pprModuleName mod),
689 ptext SLIT("in export list")]
691 unusedFixityDecl rdr_name fixity
692 = hsep [ptext SLIT("Unused fixity declaration for"), quotes (ppr rdr_name)]
694 dupFixityDecl rdr_name loc1 loc2
695 = vcat [ptext SLIT("Multiple fixity declarations for") <+> quotes (ppr rdr_name),
696 ptext SLIT("at ") <+> ppr loc1,
697 ptext SLIT("and") <+> ppr loc2]