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,
17 import HsSyn ( HsModule(..), ImportDecl(..), HsDecl(..), TyClDecl(..),
19 ForeignDecl(..), ExtName(..), ForKind(..),
20 FixitySig(..), Sig(..),
23 import RdrHsSyn ( RdrName(..), RdrNameIE, RdrNameImportDecl,
24 RdrNameHsModule, RdrNameHsDecl,
27 import RnIfaces ( getInterfaceExports, getDeclBinders, getImportedFixities,
28 recordSlurp, checkUpToDate, loadHomeInterface
30 import BasicTypes ( IfaceFlavour(..) )
36 import UniqFM ( lookupUFM )
37 import Bag ( bagToList )
38 import Maybes ( maybeToBool )
40 import SrcLoc ( SrcLoc )
41 import NameSet ( elemNameSet, emptyNameSet )
43 import Unique ( getUnique )
44 import Util ( removeDups, equivClassesByUniq )
50 %************************************************************************
52 \subsection{Get global names}
54 %************************************************************************
57 getGlobalNames :: RdrNameHsModule
58 -> RnMG (Maybe (ExportEnv,
60 NameEnv AvailInfo -- Maps a name to its parent AvailInfo
61 -- Just for in-scope things only
63 -- Nothing => no need to recompile
65 getGlobalNames (HsModule this_mod _ exports imports decls mod_loc)
66 = -- These two fix-loops are to get the right
67 -- provenance information into a Name
68 fixRn (\ ~(rec_exp_fn, _) ->
70 fixRn (\ ~(rec_rn_env, _) ->
72 rec_unqual_fn :: Name -> Bool -- Is this chap in scope unqualified?
73 rec_unqual_fn = mkPrintUnqualFn rec_rn_env
75 -- PROCESS LOCAL DECLS
76 -- Do these *first* so that the correct provenance gets
77 -- into the global name cache.
78 importsFromLocalDecls this_mod rec_exp_fn decls `thenRn` \ (local_gbl_env, local_mod_avails) ->
80 -- PROCESS IMPORT DECLS
81 mapAndUnzipRn (importsFromImportDecl rec_unqual_fn)
82 all_imports `thenRn` \ (imp_gbl_envs, imp_avails_s) ->
85 -- We put the local env second, so that a local provenance
86 -- "wins", even if a module imports itself.
88 gbl_env :: GlobalRdrEnv
89 imp_gbl_env = foldr plusGlobalRdrEnv emptyRdrEnv imp_gbl_envs
90 gbl_env = imp_gbl_env `plusGlobalRdrEnv` local_gbl_env
92 export_avails :: ExportAvails
93 export_avails = foldr plusExportAvails local_mod_avails imp_avails_s
95 returnRn (gbl_env, export_avails)
96 ) `thenRn` \ (gbl_env, export_avails) ->
99 -- We can't go for an early exit before this because we have to check
100 -- for name clashes. Consider:
102 -- module A where module B where
106 -- Suppose I've compiled everything up, and then I add a
107 -- new definition to module B, that defines "f".
109 -- Then I must detect the name clash in A before going for an early
110 -- exit. The early-exit code checks what's actually needed from B
111 -- to compile A, and of course that doesn't include B.f. That's
112 -- why we wait till after the plusRnEnv stuff to do the early-exit.
113 checkEarlyExit this_mod `thenRn` \ up_to_date ->
115 returnRn (junk_exp_fn, Nothing)
119 fixitiesFromLocalDecls gbl_env decls `thenRn` \ local_fixity_env ->
120 getImportedFixities `thenRn` \ imp_fixity_env ->
122 fixity_env = imp_fixity_env `plusNameEnv` local_fixity_env
123 rn_env = RnEnv gbl_env fixity_env
124 (_, global_avail_env) = export_avails
126 traceRn (text "fixity env" <+> vcat (map ppr (nameEnvElts fixity_env))) `thenRn_`
128 -- PROCESS EXPORT LISTS
129 exportsFromAvail this_mod exports export_avails rn_env `thenRn` \ (export_fn, export_env) ->
132 returnRn (export_fn, Just (export_env, rn_env, global_avail_env))
133 ) `thenRn` \ (_, result) ->
136 junk_exp_fn = error "RnNames:export_fn"
138 all_imports = prel_imports ++ imports
140 -- NB: opt_NoImplicitPrelude is slightly different to import Prelude ();
141 -- because the former doesn't even look at Prelude.hi for instance declarations,
142 -- whereas the latter does.
143 prel_imports | this_mod == pRELUDE ||
144 explicit_prelude_import ||
145 opt_NoImplicitPrelude
148 | otherwise = [ImportDecl pRELUDE
149 False {- Not qualified -}
150 HiFile {- Not source imported -}
151 Nothing {- No "as" -}
152 Nothing {- No import list -}
155 explicit_prelude_import
156 = not (null [ () | (ImportDecl mod qual _ _ _ _) <- imports, mod == pRELUDE ])
161 = checkErrsRn `thenRn` \ no_errs_so_far ->
162 if not no_errs_so_far then
163 -- Found errors already, so exit now
167 traceRn (text "Considering whether compilation is required...") `thenRn_`
168 if not opt_SourceUnchanged then
169 -- Source code changed and no errors yet... carry on
170 traceRn (nest 4 (text "source file changed or recompilation check turned off")) `thenRn_`
174 -- Unchanged source, and no errors yet; see if usage info
175 -- up to date, and exit if so
176 checkUpToDate mod `thenRn` \ up_to_date ->
177 putDocRn (text "Compilation" <+>
178 text (if up_to_date then "IS NOT" else "IS") <+>
179 text "required") `thenRn_`
184 importsFromImportDecl :: (Name -> Bool) -- True => print unqualified
186 -> RnMG (GlobalRdrEnv,
189 importsFromImportDecl rec_unqual_fn (ImportDecl mod qual_only as_source as_mod import_spec iloc)
190 = pushSrcLocRn iloc $
191 getInterfaceExports mod as_source `thenRn` \ avails ->
194 -- If there's an error in getInterfaceExports, (e.g. interface
195 -- file not found) then avail might be NotAvailable, so availName
196 -- in home_modules fails. Hence the guard here. Also we get lots
197 -- of spurious errors from 'filterImports' if we don't find the interface file
198 returnRn (emptyRdrEnv, mkEmptyExportAvails mod)
201 filterImports mod import_spec avails `thenRn` \ (filtered_avails, hides, explicits) ->
203 -- Load all the home modules for the things being
204 -- bought into scope. This makes sure their fixities
205 -- are loaded before we grab the FixityEnv from Ifaces
207 home_modules = [name | avail <- filtered_avails,
208 -- Doesn't take account of hiding, but that doesn't matter
210 let name = availName avail,
211 nameModule name /= mod]
212 -- This predicate is a bit of a hack.
213 -- PrelBase imports error from PrelErr.hi-boot; but error is
214 -- wired in, so its provenance doesn't say it's from an hi-boot
215 -- file. Result: disaster when PrelErr.hi doesn't exist.
217 same_module n1 n2 = nameModule n1 == nameModule n2
218 load n = loadHomeInterface (doc_str n) n
219 doc_str n = ptext SLIT("Need fixities from") <+> ppr (nameModule n) <+> parens (ppr n)
221 mapRn load (nubBy same_module home_modules) `thenRn_`
223 -- We 'improve' the provenance by setting
224 -- (a) the import-reason field, so that the Name says how it came into scope
225 -- including whether it's explicitly imported
226 -- (b) the print-unqualified field
227 -- But don't fiddle with wired-in things or we get in a twist
229 improve_prov name | isWiredInName name = name
230 | otherwise = setNameProvenance name (mk_new_prov name)
232 is_explicit name = name `elemNameSet` explicits
233 mk_new_prov name = NonLocalDef (UserImport mod iloc (is_explicit name))
238 (not qual_only) -- Maybe want unqualified names
240 filtered_avails improve_prov `thenRn` \ (rdr_name_env, mod_avails) ->
242 returnRn (rdr_name_env, mod_avails)
247 importsFromLocalDecls mod rec_exp_fn decls
248 = mapRn (getLocalDeclBinders newLocalName) decls `thenRn` \ avails_s ->
251 avails = concat avails_s
253 all_names :: [Name] -- All the defns; no dups eliminated
254 all_names = [name | avail <- avails, name <- availNames avail]
257 dups = filter non_singleton (equivClassesByUniq getUnique all_names)
259 non_singleton (x1:x2:xs) = True
260 non_singleton other = False
262 -- Check for duplicate definitions
263 mapRn (addErrRn . dupDeclErr) dups `thenRn_`
265 -- Record that locally-defined things are available
266 mapRn (recordSlurp Nothing Compulsory) avails `thenRn_`
268 -- Build the environment
270 True -- Want unqualified names
277 newLocalName rdr_name loc = newLocallyDefinedGlobalName mod (rdrNameOcc rdr_name)
280 getLocalDeclBinders :: (RdrName -> SrcLoc -> RnMG Name) -- New-name function
283 getLocalDeclBinders new_name (ValD binds)
284 = mapRn do_one (bagToList (collectTopBinders binds))
286 do_one (rdr_name, loc) = new_name rdr_name loc `thenRn` \ name ->
287 returnRn (Avail name)
289 -- foreign import declaration
290 getLocalDeclBinders new_name (ForD (ForeignDecl nm kind _ _ _ loc))
291 | binds_haskell_name kind
292 = new_name nm loc `thenRn` \ name ->
293 returnRn [Avail name]
298 getLocalDeclBinders new_name decl
299 = getDeclBinders new_name decl `thenRn` \ avail ->
301 NotAvailable -> returnRn [] -- Instance decls and suchlike
302 other -> returnRn [avail]
304 binds_haskell_name (FoImport _) = True
305 binds_haskell_name FoLabel = True
306 binds_haskell_name FoExport = False
308 fixitiesFromLocalDecls :: GlobalRdrEnv -> [RdrNameHsDecl] -> RnMG FixityEnv
309 fixitiesFromLocalDecls gbl_env decls
310 = foldlRn getFixities emptyNameEnv decls
312 getFixities :: FixityEnv -> RdrNameHsDecl -> RnMG FixityEnv
313 getFixities acc (FixD fix)
316 getFixities acc (TyClD (ClassDecl _ _ _ sigs _ _ _ _ _))
317 = foldlRn fix_decl acc [sig | FixSig sig <- sigs]
318 -- Get fixities from class decl sigs too
320 getFixities acc other_decl
323 fix_decl acc (FixitySig rdr_name fixity loc)
324 = -- Check for fixity decl for something not declared
325 case lookupRdrEnv gbl_env rdr_name of {
326 Nothing -> pushSrcLocRn loc $
327 addWarnRn (unusedFixityDecl rdr_name fixity) `thenRn_`
331 -- Check for duplicate fixity decl
332 case lookupNameEnv acc name of {
333 Just (FixitySig _ _ loc') -> addErrRn (dupFixityDecl rdr_name loc loc') `thenRn_`
337 Nothing -> returnRn (addToNameEnv acc name (FixitySig name fixity loc))
341 %************************************************************************
343 \subsection{Filtering imports}
345 %************************************************************************
347 @filterImports@ takes the @ExportEnv@ telling what the imported module makes
348 available, and filters it through the import spec (if any).
351 filterImports :: Module
352 -> Maybe (Bool, [RdrNameIE]) -- Import spec; True => hiding
353 -> [AvailInfo] -- What's available
354 -> RnMG ([AvailInfo], -- What's actually imported
355 [AvailInfo], -- What's to be hidden (the unqualified version, that is)
356 NameSet) -- What was imported explicitly
358 -- Complains if import spec mentions things that the module doesn't export
359 -- Warns/informs if import spec contains duplicates.
360 filterImports mod Nothing imports
361 = returnRn (imports, [], emptyNameSet)
363 filterImports mod (Just (want_hiding, import_items)) avails
364 = mapRn check_item import_items `thenRn` \ item_avails ->
367 -- All imported; item_avails to be hidden
368 returnRn (avails, item_avails, emptyNameSet)
370 -- Just item_avails imported; nothing to be hidden
371 returnRn (item_avails, [], availsToNameSet item_avails)
374 import_fm :: FiniteMap OccName AvailInfo
375 import_fm = listToFM [ (nameOccName name, avail)
377 name <- availNames avail]
378 -- Even though availNames returns data constructors too,
379 -- they won't make any difference because naked entities like T
380 -- in an import list map to TCOccs, not VarOccs.
382 check_item item@(IEModuleContents _)
383 = addErrRn (badImportItemErr mod item) `thenRn_`
384 returnRn NotAvailable
387 | not (maybeToBool maybe_in_import_avails) ||
388 (case filtered_avail of { NotAvailable -> True; other -> False })
389 = addErrRn (badImportItemErr mod item) `thenRn_`
390 returnRn NotAvailable
392 | dodgy_import = addWarnRn (dodgyImportWarn mod item) `thenRn_`
393 returnRn filtered_avail
395 | otherwise = returnRn filtered_avail
398 maybe_in_import_avails = lookupFM import_fm (ieOcc item)
399 Just avail = maybe_in_import_avails
400 filtered_avail = filterAvail item avail
401 dodgy_import = case (item, avail) of
402 (IEThingAll _, AvailTC _ [n]) -> True
403 -- This occurs when you import T(..), but
404 -- only export T abstractly. The single [n]
405 -- in the AvailTC is the type or class itself
413 %************************************************************************
415 \subsection{Qualifiying imports}
417 %************************************************************************
419 @qualifyImports@ takes the @ExportEnv@ after filtering through the import spec
420 of an import decl, and deals with producing an @RnEnv@ with the
421 right qualified names. It also turns the @Names@ in the @ExportEnv@ into
422 fully fledged @Names@.
425 qualifyImports :: Module -- Imported module
426 -> Bool -- True <=> want unqualified import
427 -> Maybe Module -- Optional "as M" part
428 -> [AvailInfo] -- What's to be hidden
429 -> Avails -- Whats imported and how
430 -> (Name -> Name) -- Improves the provenance on imported things
431 -> RnMG (GlobalRdrEnv, ExportAvails)
432 -- NB: the Names in ExportAvails don't have the improve-provenance
433 -- function applied to them
434 -- We could fix that, but I don't think it matters
436 qualifyImports this_mod unqual_imp as_mod hides
439 -- Make the name environment. We're talking about a
440 -- single module here, so there must be no name clashes.
441 -- In practice there only ever will be if it's the module
444 -- Add the things that are available
445 name_env1 = foldl add_avail emptyRdrEnv avails
447 -- Delete things that are hidden
448 name_env2 = foldl del_avail name_env1 hides
450 -- Create the export-availability info
451 export_avails = mkExportAvails qual_mod unqual_imp name_env2 avails
453 returnRn (name_env2, export_avails)
456 qual_mod = case as_mod of
458 Just another_name -> another_name
460 add_avail :: GlobalRdrEnv -> AvailInfo -> GlobalRdrEnv
461 add_avail env avail = foldl add_name env (availNames avail)
467 env1 = addOneToGlobalRdrEnv env (Qual qual_mod occ err_hif) better_name
468 env2 = addOneToGlobalRdrEnv env1 (Unqual occ) better_name
469 occ = nameOccName name
470 better_name = improve_prov name
472 del_avail env avail = foldl delOneFromGlobalRdrEnv env rdr_names
474 rdr_names = map (Unqual . nameOccName) (availNames avail)
476 err_hif = error "qualifyImports: hif" -- Not needed in key to mapping
480 %************************************************************************
482 \subsection{Export list processing
484 %************************************************************************
486 Processing the export list.
488 You might think that we should record things that appear in the export list as
489 ``occurrences'' (using addOccurrenceName), but you'd be wrong. We do check (here)
490 that they are in scope, but there is no need to slurp in their actual declaration
491 (which is what addOccurrenceName forces). Indeed, doing so would big trouble when
492 compiling PrelBase, because it re-exports GHC, which includes takeMVar#, whose type
493 includes ConcBase.StateAndSynchVar#, and so on...
496 type ExportAccum -- The type of the accumulating parameter of
497 -- the main worker function in exportsFromAvail
498 = ([Module], -- 'module M's seen so far
499 ExportOccMap, -- Tracks exported occurrence names
500 NameEnv AvailInfo) -- The accumulated exported stuff, kept in an env
501 -- so we can common-up related AvailInfos
503 type ExportOccMap = FiniteMap OccName (Name, RdrNameIE)
504 -- Tracks what a particular exported OccName
505 -- in an export list refers to, and which item
506 -- it came from. It's illegal to export two distinct things
507 -- that have the same occurrence name
510 exportsFromAvail :: Module
511 -> Maybe [RdrNameIE] -- Export spec
514 -> RnMG (Name -> ExportFlag, ExportEnv)
515 -- Complains if two distinct exports have same OccName
516 -- Warns about identical exports.
517 -- Complains about exports items not in scope
518 exportsFromAvail this_mod Nothing export_avails rn_env
519 = exportsFromAvail this_mod (Just [IEModuleContents this_mod]) export_avails rn_env
521 exportsFromAvail this_mod (Just export_items)
522 (mod_avail_env, entity_avail_env)
523 (RnEnv global_name_env fixity_env)
524 = foldlRn exports_from_item
525 ([], emptyFM, emptyNameEnv) export_items `thenRn` \ (_, _, export_avail_map) ->
527 export_avails :: [AvailInfo]
528 export_avails = nameEnvElts export_avail_map
530 export_names :: NameSet
531 export_names = availsToNameSet export_avails
533 -- Export only those fixities that are for names that are
534 -- (a) defined in this module
536 export_fixities :: [(Name,Fixity)]
537 export_fixities = [ (name,fixity)
538 | FixitySig name fixity _ <- nameEnvElts fixity_env,
539 name `elemNameSet` export_names,
540 isLocallyDefined name
543 export_fn :: Name -> ExportFlag
544 export_fn = mk_export_fn export_names
546 returnRn (export_fn, ExportEnv export_avails export_fixities)
549 exports_from_item :: ExportAccum -> RdrNameIE -> RnMG ExportAccum
551 exports_from_item acc@(mods, occs, avails) ie@(IEModuleContents mod)
552 | mod `elem` mods -- Duplicate export of M
553 = warnCheckRn opt_WarnDuplicateExports
554 (dupModuleExport mod) `thenRn_`
558 = case lookupFM mod_avail_env mod of
559 Nothing -> failWithRn acc (modExportErr mod)
560 Just mod_avails -> foldlRn (check_occs ie) occs mod_avails `thenRn` \ occs' ->
562 avails' = foldl add_avail avails mod_avails
564 returnRn (mod:mods, occs', avails')
566 exports_from_item acc@(mods, occs, avails) ie
567 | not (maybeToBool maybe_in_scope)
568 = failWithRn acc (unknownNameErr (ieName ie))
570 | not (null dup_names)
571 = addNameClashErrRn rdr_name (name:dup_names) `thenRn_`
575 -- I can't see why this should ever happen; if the thing is in scope
576 -- at all it ought to have some availability
577 | not (maybeToBool maybe_avail)
578 = pprTrace "exportsFromAvail: curious Nothing:" (ppr name)
583 = failWithRn acc (exportItemErr ie export_avail)
585 | otherwise -- Phew! It's OK! Now to check the occurrence stuff!
586 = check_occs ie occs export_avail `thenRn` \ occs' ->
587 returnRn (mods, occs', add_avail avails export_avail)
591 maybe_in_scope = lookupFM global_name_env rdr_name
592 Just (name:dup_names) = maybe_in_scope
593 maybe_avail = lookupUFM entity_avail_env name
594 Just avail = maybe_avail
595 export_avail = filterAvail ie avail
596 enough_avail = case export_avail of {NotAvailable -> False; other -> True}
598 add_avail avails avail = addToNameEnv_C plusAvail avails (availName avail) avail
600 check_occs :: RdrNameIE -> ExportOccMap -> AvailInfo -> RnMG ExportOccMap
601 check_occs ie occs avail
602 = foldlRn check occs (availNames avail)
605 = case lookupFM occs name_occ of
606 Nothing -> returnRn (addToFM occs name_occ (name, ie))
608 | name == name' -> -- Duplicate export
609 warnCheckRn opt_WarnDuplicateExports
610 (dupExportWarn name_occ ie ie') `thenRn_`
613 | otherwise -> -- Same occ name but different names: an error
614 failWithRn occs (exportClashErr name_occ ie ie')
616 name_occ = nameOccName name
618 mk_export_fn :: NameSet -> (Name -> ExportFlag)
619 mk_export_fn exported_names
620 = \name -> if name `elemNameSet` exported_names
625 %************************************************************************
629 %************************************************************************
632 badImportItemErr mod ie
633 = sep [ptext SLIT("Module"), quotes (pprModule mod),
634 ptext SLIT("does not export"), quotes (ppr ie)]
636 dodgyImportWarn mod (IEThingAll tc)
637 = sep [ptext SLIT("Module") <+> quotes (pprModule mod) <+> ptext SLIT("exports") <+> quotes (ppr tc),
638 ptext SLIT("with no constructors/class operations;"),
639 ptext SLIT("yet it is imported with a (..)")]
642 = hsep [ ptext SLIT("Unknown module in export list: module"), quotes (pprModule mod)]
644 exportItemErr export_item NotAvailable
645 = sep [ ptext SLIT("Export item not in scope:"), quotes (ppr export_item)]
647 exportItemErr export_item avail
648 = hang (ptext SLIT("Export item not fully in scope:"))
649 4 (vcat [hsep [ptext SLIT("Wanted: "), ppr export_item],
650 hsep [ptext SLIT("Available:"), ppr (ieOcc export_item), pprAvail avail]])
652 exportClashErr occ_name ie1 ie2
653 = hsep [ptext SLIT("The export items"), quotes (ppr ie1), ptext SLIT("and"), quotes (ppr ie2),
654 ptext SLIT("create conflicting exports for"), quotes (ppr occ_name)]
657 = vcat [ptext SLIT("Multiple declarations of") <+> quotes (ppr n),
658 nest 4 (vcat (map pp (n:ns)))]
660 pp n = pprProvenance (getNameProvenance n)
662 dupExportWarn occ_name ie1 ie2
663 = hsep [quotes (ppr occ_name),
664 ptext SLIT("is exported by"), quotes (ppr ie1),
665 ptext SLIT("and"), quotes (ppr ie2)]
668 = hsep [ptext SLIT("Duplicate"),
669 quotes (ptext SLIT("Module") <+> pprModule mod),
670 ptext SLIT("in export list")]
672 unusedFixityDecl rdr_name fixity
673 = hsep [ptext SLIT("Unused fixity declaration for"), quotes (ppr rdr_name)]
675 dupFixityDecl rdr_name loc1 loc2
676 = vcat [ptext SLIT("Multiple fixity declarations for") <+> quotes (ppr rdr_name),
677 ptext SLIT("at ") <+> ppr loc1,
678 ptext SLIT("and") <+> ppr loc2]