2 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
4 \section[RnNames]{Extracting imported and top-level names in scope}
8 rnImports, getLocalNonValBinders,
9 rnExports, extendGlobalRdrEnvRn,
10 reportUnusedNames, finishDeprecations,
13 #include "HsVersions.h"
18 import RnHsDoc ( rnHsDoc )
19 import IfaceEnv ( ifaceExportNames )
20 import LoadIface ( loadSrcInterface, loadSysInterface )
21 import TcRnMonad hiding (LIE)
36 import BasicTypes ( DeprecTxt )
37 import DriverPhases ( isHsBoot )
41 import Data.List ( partition, concatMap, (\\), delete )
42 import IO ( openFile, IOMode(..) )
43 import Monad ( when, mplus )
48 %************************************************************************
52 %************************************************************************
55 rnImports :: [LImportDecl RdrName]
56 -> RnM ([LImportDecl Name], GlobalRdrEnv, ImportAvails,AnyHpcUsage)
59 -- PROCESS IMPORT DECLS
60 -- Do the non {- SOURCE -} ones first, so that we get a helpful
61 -- warning for {- SOURCE -} ones that are unnecessary
62 = do this_mod <- getModule
63 implicit_prelude <- doptM Opt_ImplicitPrelude
64 let prel_imports = mkPrelImports this_mod implicit_prelude imports
65 (source, ordinary) = partition is_source_import imports
66 is_source_import (L _ (ImportDecl _ is_boot _ _ _)) = is_boot
68 ifOptM Opt_WarnImplicitPrelude (
69 when (notNull prel_imports) $ addWarn (implicitPreludeWarn)
72 stuff1 <- mapM (rnImportDecl this_mod) (prel_imports ++ ordinary)
73 stuff2 <- mapM (rnImportDecl this_mod) source
74 let (decls, rdr_env, imp_avails,hpc_usage) = combine (stuff1 ++ stuff2)
75 return (decls, rdr_env, imp_avails,hpc_usage)
78 combine :: [(LImportDecl Name, GlobalRdrEnv, ImportAvails,AnyHpcUsage)]
79 -> ([LImportDecl Name], GlobalRdrEnv, ImportAvails,AnyHpcUsage)
80 combine = foldr plus ([], emptyGlobalRdrEnv, emptyImportAvails,False)
81 where plus (decl, gbl_env1, imp_avails1,hpc_usage1)
82 (decls, gbl_env2, imp_avails2,hpc_usage2)
84 gbl_env1 `plusGlobalRdrEnv` gbl_env2,
85 imp_avails1 `plusImportAvails` imp_avails2,
86 hpc_usage1 || hpc_usage2)
88 mkPrelImports :: Module -> Bool -> [LImportDecl RdrName] -> [LImportDecl RdrName]
89 -- Consruct the implicit declaration "import Prelude" (or not)
91 -- NB: opt_NoImplicitPrelude is slightly different to import Prelude ();
92 -- because the former doesn't even look at Prelude.hi for instance
93 -- declarations, whereas the latter does.
94 mkPrelImports this_mod implicit_prelude import_decls
96 || explicit_prelude_import
97 || not implicit_prelude
99 | otherwise = [preludeImportDecl]
101 explicit_prelude_import
102 = notNull [ () | L _ (ImportDecl mod _ _ _ _) <- import_decls,
103 unLoc mod == pRELUDE_NAME ]
105 preludeImportDecl :: LImportDecl RdrName
108 ImportDecl (L loc pRELUDE_NAME)
109 False {- Not a boot interface -}
110 False {- Not qualified -}
111 Nothing {- No "as" -}
112 Nothing {- No import list -}
114 loc = mkGeneralSrcSpan (fsLit "Implicit import declaration")
117 rnImportDecl :: Module
118 -> LImportDecl RdrName
119 -> RnM (LImportDecl Name, GlobalRdrEnv, ImportAvails,AnyHpcUsage)
121 rnImportDecl this_mod (L loc (ImportDecl loc_imp_mod_name want_boot
122 qual_only as_mod imp_details))
126 -- If there's an error in loadInterface, (e.g. interface
127 -- file not found) we get lots of spurious errors from 'filterImports'
129 imp_mod_name = unLoc loc_imp_mod_name
130 doc = ppr imp_mod_name <+> ptext (sLit "is directly imported")
132 iface <- loadSrcInterface doc imp_mod_name want_boot
134 -- Compiler sanity check: if the import didn't say
135 -- {-# SOURCE #-} we should not get a hi-boot file
136 WARN( not want_boot && mi_boot iface, ppr imp_mod_name ) (do
138 -- Issue a user warning for a redundant {- SOURCE -} import
139 -- NB that we arrange to read all the ordinary imports before
140 -- any of the {- SOURCE -} imports
141 warnIf (want_boot && not (mi_boot iface))
142 (warnRedundantSourceImport imp_mod_name)
145 imp_mod = mi_module iface
146 deprecs = mi_deprecs iface
147 orph_iface = mi_orphan iface
148 has_finsts = mi_finsts iface
151 filtered_exports = filter not_this_mod (mi_exports iface)
152 not_this_mod (mod,_) = mod /= this_mod
153 -- If the module exports anything defined in this module, just
154 -- ignore it. Reason: otherwise it looks as if there are two
155 -- local definition sites for the thing, and an error gets
156 -- reported. Easiest thing is just to filter them out up
157 -- front. This situation only arises if a module imports
158 -- itself, or another module that imported it. (Necessarily,
159 -- this invoves a loop.)
161 -- Tiresome consequence: if you say
166 -- module B( AType ) where
167 -- import {-# SOURCE #-} A( AType )
169 -- then you'll get a 'B does not export AType' message. Oh well.
171 qual_mod_name = case as_mod of
172 Nothing -> imp_mod_name
173 Just another_name -> another_name
174 imp_spec = ImpDeclSpec { is_mod = imp_mod_name, is_qual = qual_only,
175 is_dloc = loc, is_as = qual_mod_name }
178 -- Get the total exports from this module
179 total_avails <- ifaceExportNames filtered_exports
181 -- filter the imports according to the import declaration
182 (new_imp_details, gbl_env) <-
183 filterImports iface imp_spec imp_details total_avails
188 -- Compute new transitive dependencies
190 orphans | orph_iface = ASSERT( not (imp_mod `elem` dep_orphs deps) )
191 imp_mod : dep_orphs deps
192 | otherwise = dep_orphs deps
194 finsts | has_finsts = ASSERT( not (imp_mod `elem` dep_finsts deps) )
195 imp_mod : dep_finsts deps
196 | otherwise = dep_finsts deps
198 pkg = modulePackageId (mi_module iface)
200 (dependent_mods, dependent_pkgs)
201 | pkg == thisPackage dflags =
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 -- True <=> import M ()
223 import_all = case imp_details of
224 Just (is_hiding, ls) -> not is_hiding && null ls
227 imports = ImportAvails {
228 imp_mods = unitModuleEnv imp_mod (imp_mod, [(qual_mod_name, import_all, loc)]),
231 imp_dep_mods = mkModDeps dependent_mods,
232 imp_dep_pkgs = dependent_pkgs
235 -- Complain if we import a deprecated module
236 ifOptM Opt_WarnDeprecations (
238 DeprecAll txt -> addWarn (moduleDeprec imp_mod_name txt)
242 let new_imp_decl = L loc (ImportDecl loc_imp_mod_name want_boot
243 qual_only as_mod new_imp_details)
245 return (new_imp_decl, gbl_env, imports, mi_hpc iface)
248 warnRedundantSourceImport :: ModuleName -> SDoc
249 warnRedundantSourceImport mod_name
250 = ptext (sLit "Unnecessary {-# SOURCE #-} in the import of module")
251 <+> quotes (ppr mod_name)
255 %************************************************************************
257 importsFromLocalDecls
259 %************************************************************************
261 From the top-level declarations of this module produce
262 * the lexical environment
264 created by its bindings.
266 Note [Shadowing in extendGlobalRdrEnvRn]
267 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
268 Usually when etending the GlobalRdrEnv we complain if a new binding
269 duplicates an existing one. By adding the bindings one at a time,
270 this check also complains if we add two new bindings for the same name.
271 (Remember that in Template Haskell the duplicates might *already be*
272 in the GlobalRdrEnv from higher up the module.)
274 But with a Template Haskell quotation we want to *shadow*:
276 Here the inner binding for 'f' simply shadows the outer one.
277 And that applies even if the binding for 'f' is in a where-clause,
278 and hence is in the *local* RdrEnv not the *global* RdrEnv.
280 Hence the shadowP boolean passed in.
283 extendGlobalRdrEnvRn :: Bool -- Note [Shadowing in extendGlobalRdrEnvRn]
286 -> RnM (TcGblEnv, TcLclEnv)
287 -- Updates both the GlobalRdrEnv and the FixityEnv
288 -- We return a new TcLclEnv only becuase we might have to
289 -- delete some bindings from it; see Note [Shadowing in extendGlobalRdrEnvRn]
291 extendGlobalRdrEnvRn shadowP avails new_fixities
292 = do { (gbl_env, lcl_env) <- getEnvs
293 ; let rdr_env = tcg_rdr_env gbl_env
294 fix_env = tcg_fix_env gbl_env
296 -- Delete new_occs from global and local envs
297 -- We are going to shadow them
298 -- See Note [Shadowing in extendGlobalRdrEnvRn]
299 new_occs = map (nameOccName . gre_name) gres
300 rdr_env1 = hideSomeUnquals rdr_env new_occs
301 lcl_env1 = lcl_env { tcl_rdr = delListFromOccEnv (tcl_rdr lcl_env) new_occs }
303 -- Note [Shadowing in extendGlobalRdrEnvRn]
304 (rdr_env2, lcl_env2) | shadowP = (rdr_env1, lcl_env1)
305 | otherwise = (rdr_env, lcl_env)
307 rdr_env3 = foldl extendGlobalRdrEnv rdr_env2 gres
308 fix_env' = foldl extend_fix_env fix_env gres
309 (rdr_env', dups) = findLocalDupsRdrEnv rdr_env3 new_occs
311 gbl_env' = gbl_env { tcg_rdr_env = rdr_env', tcg_fix_env = fix_env' }
313 ; mapM_ addDupDeclErr dups
315 ; traceRn (text "extendGlobalRdrEnvRn" <+> (ppr new_fixities $$ ppr fix_env $$ ppr fix_env'))
316 ; return (gbl_env', lcl_env2) }
318 gres = gresFromAvails LocalDef avails
320 -- If there is a fixity decl for the gre, add it to the fixity env
321 extend_fix_env fix_env gre
322 | Just (L _ fi) <- lookupFsEnv new_fixities (occNameFS occ)
323 = extendNameEnv fix_env name (FixItem occ fi)
328 occ = nameOccName name
331 @getLocalDeclBinders@ returns the names for an @HsDecl@. It's
332 used for source code.
334 *** See "THE NAMING STORY" in HsDecls ****
336 Instances of type families
337 ~~~~~~~~~~~~~~~~~~~~~~~~~~
338 Indexed data/newtype instances contain data constructors that we need to
339 collect, too. Moreover, we need to descend into the data/newtypes instances
340 of associated families.
342 We need to be careful with the handling of the type constructor of each type
343 instance as the family constructor is already defined, and we want to avoid
344 raising a duplicate declaration error. So, we make a new name for it, but
345 don't return it in the 'AvailInfo'.
348 getLocalNonValBinders :: HsGroup RdrName -> RnM [AvailInfo]
349 -- Get all the top-level binders bound the group *except*
350 -- for value bindings, which are treated separately
351 -- Specificaly we return AvailInfo for
356 -- (in hs-boot files) value signatures
358 getLocalNonValBinders group
359 = do { gbl_env <- getGblEnv
360 ; get_local_binders gbl_env group }
362 get_local_binders :: TcGblEnv -> HsGroup RdrName -> RnM [GenAvailInfo Name]
363 get_local_binders gbl_env (HsGroup {hs_valds = ValBindsIn _ val_sigs,
364 hs_tyclds = tycl_decls,
365 hs_instds = inst_decls,
366 hs_fords = foreign_decls })
367 = do { tc_names_s <- mapM new_tc tycl_decls
368 ; at_names_s <- mapM inst_ats inst_decls
369 ; val_names <- mapM new_simple val_bndrs
370 ; return (val_names ++ tc_names_s ++ concat at_names_s) }
372 mod = tcg_mod gbl_env
373 is_hs_boot = isHsBoot (tcg_src gbl_env) ;
375 for_hs_bndrs = [nm | L _ (ForeignImport nm _ _) <- foreign_decls]
377 -- In a hs-boot file, the value binders come from the
378 -- *signatures*, and there should be no foreign binders
379 val_bndrs | is_hs_boot = [nm | L _ (TypeSig nm _) <- val_sigs]
380 | otherwise = for_hs_bndrs
382 new_simple rdr_name = do
383 nm <- newTopSrcBinder mod rdr_name
387 | isFamInstDecl (unLoc tc_decl)
388 = do { main_name <- lookupFamInstDeclBndr mod main_rdr
389 ; sub_names <- mapM (newTopSrcBinder mod) sub_rdrs
390 ; return (AvailTC main_name sub_names) }
391 -- main_name is not bound here!
393 = do { main_name <- newTopSrcBinder mod main_rdr
394 ; sub_names <- mapM (newTopSrcBinder mod) sub_rdrs
395 ; return (AvailTC main_name (main_name : sub_names)) }
397 (main_rdr : sub_rdrs) = tyClDeclNames (unLoc tc_decl)
400 = mapM new_tc (instDeclATs (unLoc inst_decl))
402 get_local_binders _ g = pprPanic "get_local_binders" (ppr g)
406 %************************************************************************
408 \subsection{Filtering imports}
410 %************************************************************************
412 @filterImports@ takes the @ExportEnv@ telling what the imported module makes
413 available, and filters it through the import spec (if any).
416 filterImports :: ModIface
417 -> ImpDeclSpec -- The span for the entire import decl
418 -> Maybe (Bool, [LIE RdrName]) -- Import spec; True => hiding
419 -> [AvailInfo] -- What's available
420 -> RnM (Maybe (Bool, [LIE Name]), -- Import spec w/ Names
421 GlobalRdrEnv) -- Same again, but in GRE form
422 filterImports _ decl_spec Nothing all_avails
423 = return (Nothing, mkGlobalRdrEnv (gresFromAvails prov all_avails))
425 prov = Imported [ImpSpec { is_decl = decl_spec, is_item = ImpAll }]
428 filterImports iface decl_spec (Just (want_hiding, import_items)) all_avails
429 = do -- check for errors, convert RdrNames to Names
430 opt_typeFamilies <- doptM Opt_TypeFamilies
431 items1 <- mapM (lookup_lie opt_typeFamilies) import_items
433 let items2 :: [(LIE Name, AvailInfo)]
434 items2 = concat items1
435 -- NB the AvailInfo may have duplicates, and several items
436 -- for the same parent; e.g N(x) and N(y)
438 names = availsToNameSet (map snd items2)
439 keep n = not (n `elemNameSet` names)
440 pruned_avails = filterAvails keep all_avails
441 hiding_prov = Imported [ImpSpec { is_decl = decl_spec, is_item = ImpAll }]
443 gres | want_hiding = gresFromAvails hiding_prov pruned_avails
444 | otherwise = concatMap (gresFromIE decl_spec) items2
446 return (Just (want_hiding, map fst items2), mkGlobalRdrEnv gres)
448 -- This environment is how we map names mentioned in the import
449 -- list to the actual Name they correspond to, and the name family
450 -- that the Name belongs to (the AvailInfo). The situation is
451 -- complicated by associated families, which introduce a three-level
452 -- hierachy, where class = grand parent, assoc family = parent, and
453 -- data constructors = children. The occ_env entries for associated
454 -- families needs to capture all this information; hence, we have the
455 -- third component of the environment that gives the class name (=
456 -- grand parent) in case of associated families.
458 -- This env will have entries for data constructors too,
459 -- they won't make any difference because naked entities like T
460 -- in an import list map to TcOccs, not VarOccs.
461 occ_env :: OccEnv (Name, -- the name
462 AvailInfo, -- the export item providing the name
463 Maybe Name) -- the parent of associated types
464 occ_env = mkOccEnv_C combine [ (nameOccName n, (n, a, Nothing))
465 | a <- all_avails, n <- availNames a]
467 -- we know that (1) there are at most entries for one name, (2) their
468 -- first component is identical, (3) they are for tys/cls, and (4) one
469 -- entry has the name in its parent position (the other doesn't)
470 combine (name, AvailTC p1 subs1, Nothing)
471 (_ , AvailTC p2 subs2, Nothing)
473 (parent, subs) = if p1 == name then (p2, subs1) else (p1, subs2)
475 (name, AvailTC name subs, Just parent)
476 combine x y = pprPanic "filterImports/combine" (ppr x $$ ppr y)
478 lookup_lie :: Bool -> LIE RdrName -> TcRn [(LIE Name, AvailInfo)]
479 lookup_lie opt_typeFamilies (L loc ieRdr)
481 stuff <- setSrcSpan loc $
482 case lookup_ie opt_typeFamilies ieRdr of
483 Failed err -> addErr err >> return []
484 Succeeded a -> return a
485 checkDodgyImport stuff
486 return [ (L loc ie, avail) | (ie,avail) <- stuff ]
488 -- Warn when importing T(..) if T was exported abstractly
489 checkDodgyImport stuff
490 | IEThingAll n <- ieRdr, (_, AvailTC _ [_]):_ <- stuff
491 = ifOptM Opt_WarnDodgyImports (addWarn (dodgyImportWarn n))
492 -- NB. use the RdrName for reporting the warning
496 -- For each import item, we convert its RdrNames to Names,
497 -- and at the same time construct an AvailInfo corresponding
498 -- to what is actually imported by this item.
499 -- Returns Nothing on error.
500 -- We return a list here, because in the case of an import
501 -- item like C, if we are hiding, then C refers to *both* a
502 -- type/class and a data constructor. Moreover, when we import
503 -- data constructors of an associated family, we need separate
504 -- AvailInfos for the data constructors and the family (as they have
505 -- different parents). See the discussion at occ_env.
506 lookup_ie :: Bool -> IE RdrName -> MaybeErr Message [(IE Name,AvailInfo)]
507 lookup_ie opt_typeFamilies ie
508 = let bad_ie = Failed (badImportItemErr iface decl_spec ie)
510 lookup_name rdrName =
511 case lookupOccEnv occ_env (rdrNameOcc rdrName) of
517 (name, avail, _) <- lookup_name n
518 return [(IEVar name, trimAvail avail name)]
521 (name, avail@(AvailTC name2 subs), mb_parent) <- lookup_name tc
523 -- non-associated ty/cls
524 Nothing -> return [(IEThingAll name, avail)]
526 Just parent -> return [(IEThingAll name,
527 AvailTC name2 (subs \\ [name])),
528 (IEThingAll name, AvailTC parent [name])]
531 | want_hiding -- hiding ( C )
532 -- Here the 'C' can be a data constructor
533 -- *or* a type/class, or even both
534 -> let tc_name = lookup_name tc
535 dc_name = lookup_name (setRdrNameSpace tc srcDataName)
537 case catMaybeErr [ tc_name, dc_name ] of
539 names -> return [mkIEThingAbs name | name <- names]
541 -> do nameAvail <- lookup_name tc
542 return [mkIEThingAbs nameAvail]
544 IEThingWith tc ns -> do
545 (name, AvailTC _ subnames, mb_parent) <- lookup_name tc
547 env = mkOccEnv [(nameOccName s, s) | s <- subnames]
548 mb_children = map (lookupOccEnv env . rdrNameOcc) ns
549 children <- if any isNothing mb_children
551 else return (catMaybes mb_children)
552 -- check for proper import of type families
553 when (not opt_typeFamilies && any isTyConName children) $
554 Failed (typeItemErr (head . filter isTyConName $ children)
555 (text "in import list"))
557 -- non-associated ty/cls
558 Nothing -> return [(IEThingWith name children,
559 AvailTC name (name:children))]
561 Just parent -> return [(IEThingWith name children,
562 AvailTC name children),
563 (IEThingWith name children,
564 AvailTC parent [name])]
566 _other -> Failed illegalImportItemErr
567 -- could be IEModuleContents, IEGroup, IEDoc, IEDocNamed
571 mkIEThingAbs (n, av, Nothing ) = (IEThingAbs n, trimAvail av n)
572 mkIEThingAbs (n, _, Just parent) = (IEThingAbs n, AvailTC parent [n])
575 catMaybeErr :: [MaybeErr err a] -> [a]
576 catMaybeErr ms = [ a | Succeeded a <- ms ]
579 %************************************************************************
583 %************************************************************************
586 -- | make a 'GlobalRdrEnv' where all the elements point to the same
587 -- import declaration (useful for "hiding" imports, or imports with
589 gresFromAvails :: Provenance -> [AvailInfo] -> [GlobalRdrElt]
590 gresFromAvails prov avails
591 = concatMap (gresFromAvail (const prov)) avails
593 gresFromAvail :: (Name -> Provenance) -> AvailInfo -> [GlobalRdrElt]
594 gresFromAvail prov_fn avail
595 = [ GRE {gre_name = n,
596 gre_par = availParent n avail,
597 gre_prov = prov_fn n}
598 | n <- availNames avail ]
600 greAvail :: GlobalRdrElt -> AvailInfo
601 greAvail gre = mkUnitAvail (gre_name gre) (gre_par gre)
603 mkUnitAvail :: Name -> Parent -> AvailInfo
604 mkUnitAvail me (ParentIs p) = AvailTC p [me]
605 mkUnitAvail me NoParent | isTyConName me = AvailTC me [me]
606 | otherwise = Avail me
608 plusAvail :: GenAvailInfo Name -> GenAvailInfo Name -> GenAvailInfo Name
609 plusAvail (Avail n1) (Avail _) = Avail n1
610 plusAvail (AvailTC _ ns1) (AvailTC n2 ns2) = AvailTC n2 (ns1 `unionLists` ns2)
611 plusAvail a1 a2 = pprPanic "RnEnv.plusAvail" (hsep [ppr a1,ppr a2])
613 availParent :: Name -> AvailInfo -> Parent
614 availParent _ (Avail _) = NoParent
615 availParent n (AvailTC m _) | n == m = NoParent
616 | otherwise = ParentIs m
618 trimAvail :: AvailInfo -> Name -> AvailInfo
619 trimAvail (Avail n) _ = Avail n
620 trimAvail (AvailTC n ns) m = ASSERT( m `elem` ns) AvailTC n [m]
622 -- | filters 'AvailInfo's by the given predicate
623 filterAvails :: (Name -> Bool) -> [AvailInfo] -> [AvailInfo]
624 filterAvails keep avails = foldr (filterAvail keep) [] avails
626 -- | filters an 'AvailInfo' by the given predicate
627 filterAvail :: (Name -> Bool) -> AvailInfo -> [AvailInfo] -> [AvailInfo]
628 filterAvail keep ie rest =
630 Avail n | keep n -> ie : rest
633 let left = filter keep ns in
634 if null left then rest else AvailTC tc left : rest
636 -- | Given an import/export spec, construct the appropriate 'GlobalRdrElt's.
637 gresFromIE :: ImpDeclSpec -> (LIE Name, AvailInfo) -> [GlobalRdrElt]
638 gresFromIE decl_spec (L loc ie, avail)
639 = gresFromAvail prov_fn avail
641 is_explicit = case ie of
642 IEThingAll name -> \n -> n == name
644 prov_fn name = Imported [imp_spec]
646 imp_spec = ImpSpec { is_decl = decl_spec, is_item = item_spec }
647 item_spec = ImpSome { is_explicit = is_explicit name, is_iloc = loc }
649 mkChildEnv :: [GlobalRdrElt] -> NameEnv [Name]
650 mkChildEnv gres = foldr add emptyNameEnv gres
652 add (GRE { gre_name = n, gre_par = ParentIs p }) env = extendNameEnv_C (++) env p [n]
655 findChildren :: NameEnv [Name] -> Name -> [Name]
656 findChildren env n = lookupNameEnv env n `orElse` []
659 ---------------------------------------
662 All this AvailEnv stuff is hardly used; only in a very small
663 part of RnNames. Todo: remove?
664 ---------------------------------------
667 type AvailEnv = NameEnv AvailInfo -- Maps a Name to the AvailInfo that contains it
669 emptyAvailEnv :: AvailEnv
670 emptyAvailEnv = emptyNameEnv
672 unitAvailEnv :: AvailInfo -> AvailEnv
673 unitAvailEnv a = unitNameEnv (availName a) a
675 plusAvailEnv :: AvailEnv -> AvailEnv -> AvailEnv
676 plusAvailEnv = plusNameEnv_C plusAvail
678 availEnvElts :: AvailEnv -> [AvailInfo]
679 availEnvElts = nameEnvElts
681 addAvail :: AvailEnv -> AvailInfo -> AvailEnv
682 addAvail avails avail = extendNameEnv_C plusAvail avails (availName avail) avail
684 mkAvailEnv :: [AvailInfo] -> AvailEnv
685 -- 'avails' may have several items with the same availName
686 -- E.g import Ix( Ix(..), index )
687 -- will give Ix(Ix,index,range) and Ix(index)
688 -- We want to combine these; addAvail does that
689 mkAvailEnv avails = foldl addAvail emptyAvailEnv avails
691 -- After combining the avails, we need to ensure that the parent name is the
692 -- first entry in the list of subnames, if it is included at all. (Subsequent
693 -- functions rely on that.)
694 normaliseAvail :: AvailInfo -> AvailInfo
695 normaliseAvail avail@(Avail _) = avail
696 normaliseAvail (AvailTC name subs) = AvailTC name subs'
698 subs' = if name `elem` subs then name : (delete name subs) else subs
700 -- | combines 'AvailInfo's from the same family
701 nubAvails :: [AvailInfo] -> [AvailInfo]
702 nubAvails avails = map normaliseAvail . nameEnvElts . mkAvailEnv $ avails
706 %************************************************************************
708 \subsection{Export list processing}
710 %************************************************************************
712 Processing the export list.
714 You might think that we should record things that appear in the export
715 list as ``occurrences'' (using @addOccurrenceName@), but you'd be
716 wrong. We do check (here) that they are in scope, but there is no
717 need to slurp in their actual declaration (which is what
718 @addOccurrenceName@ forces).
720 Indeed, doing so would big trouble when compiling @PrelBase@, because
721 it re-exports @GHC@, which includes @takeMVar#@, whose type includes
722 @ConcBase.StateAndSynchVar#@, and so on...
725 type ExportAccum -- The type of the accumulating parameter of
726 -- the main worker function in rnExports
727 = ([LIE Name], -- Export items with Names
728 ExportOccMap, -- Tracks exported occurrence names
729 [AvailInfo]) -- The accumulated exported stuff
732 emptyExportAccum :: ExportAccum
733 emptyExportAccum = ([], emptyOccEnv, [])
735 type ExportOccMap = OccEnv (Name, IE RdrName)
736 -- Tracks what a particular exported OccName
737 -- in an export list refers to, and which item
738 -- it came from. It's illegal to export two distinct things
739 -- that have the same occurrence name
741 rnExports :: Bool -- False => no 'module M(..) where' header at all
742 -> Maybe [LIE RdrName] -- Nothing => no explicit export list
746 -- Complains if two distinct exports have same OccName
747 -- Warns about identical exports.
748 -- Complains about exports items not in scope
750 rnExports explicit_mod exports
751 tcg_env@(TcGblEnv { tcg_mod = this_mod,
752 tcg_rdr_env = rdr_env,
753 tcg_imports = imports })
755 -- If the module header is omitted altogether, then behave
756 -- as if the user had written "module Main(main) where..."
757 -- EXCEPT in interactive mode, when we behave as if he had
758 -- written "module Main where ..."
759 -- Reason: don't want to complain about 'main' not in scope
760 -- in interactive mode
763 | explicit_mod = exports
764 | ghcLink dflags == LinkInMemory = Nothing
765 | otherwise = Just ([noLoc (IEVar main_RDR_Unqual)])
766 -- ToDo: the 'noLoc' here is unhelpful if 'main'
767 -- turns out to be out of scope
769 ; (rn_exports, avails) <- exports_from_avail real_exports rdr_env imports this_mod
770 ; let final_avails = nubAvails avails -- Combine families
772 ; return (tcg_env { tcg_exports = final_avails,
773 tcg_rn_exports = case tcg_rn_exports tcg_env of
775 Just _ -> rn_exports,
776 tcg_dus = tcg_dus tcg_env `plusDU`
777 usesOnly (availsToNameSet final_avails) }) }
780 exports_from_avail :: Maybe [LIE RdrName]
781 -- Nothing => no explicit export list
785 -> RnM (Maybe [LIE Name], [AvailInfo])
787 exports_from_avail Nothing rdr_env _imports _this_mod
788 = -- The same as (module M) where M is the current module name,
789 -- so that's how we handle it.
791 avails = [ greAvail gre | gre <- globalRdrEnvElts rdr_env,
794 return (Nothing, avails)
796 exports_from_avail (Just rdr_items) rdr_env imports this_mod
797 = do (ie_names, _, exports) <- foldlM do_litem emptyExportAccum rdr_items
799 return (Just ie_names, exports)
801 do_litem :: ExportAccum -> LIE RdrName -> RnM ExportAccum
802 do_litem acc lie = setSrcSpan (getLoc lie) (exports_from_item acc lie)
804 kids_env :: NameEnv [Name] -- Maps a parent to its in-scope children
805 kids_env = mkChildEnv (globalRdrEnvElts rdr_env)
807 imported_modules = [ qual_name
808 | (_, xs) <- moduleEnvElts $ imp_mods imports,
809 (qual_name, _, _) <- xs ]
811 exports_from_item :: ExportAccum -> LIE RdrName -> RnM ExportAccum
812 exports_from_item acc@(ie_names, occs, exports)
813 (L loc ie@(IEModuleContents mod))
814 | let earlier_mods = [ mod | (L _ (IEModuleContents mod)) <- ie_names ]
815 , mod `elem` earlier_mods -- Duplicate export of M
816 = do { warn_dup_exports <- doptM Opt_WarnDuplicateExports ;
817 warnIf warn_dup_exports (dupModuleExport mod) ;
821 = do { implicit_prelude <- doptM Opt_ImplicitPrelude
822 ; let { exportValid = (mod `elem` imported_modules)
823 || (moduleName this_mod == mod)
824 ; gres = filter (isModuleExported implicit_prelude mod)
825 (globalRdrEnvElts rdr_env)
828 ; checkErr exportValid (moduleNotImported mod)
829 ; warnIf (exportValid && null gres) (nullModuleExport mod)
831 ; occs' <- check_occs ie occs (map gre_name gres)
832 -- This check_occs not only finds conflicts
833 -- between this item and others, but also
834 -- internally within this item. That is, if
835 -- 'M.x' is in scope in several ways, we'll have
836 -- several members of mod_avails with the same
838 ; return (L loc (IEModuleContents mod) : ie_names,
839 occs', map greAvail gres ++ exports) }
841 exports_from_item acc@(lie_names, occs, exports) (L loc ie)
843 = do new_ie <- lookup_doc_ie ie
844 return (L loc new_ie : lie_names, occs, exports)
847 = do (new_ie, avail) <- lookup_ie ie
848 if isUnboundName (ieName new_ie)
849 then return acc -- Avoid error cascade
852 occs' <- check_occs ie occs (availNames avail)
854 return (L loc new_ie : lie_names, occs', avail : exports)
857 lookup_ie :: IE RdrName -> RnM (IE Name, AvailInfo)
858 lookup_ie (IEVar rdr)
859 = do gre <- lookupGreRn rdr
860 return (IEVar (gre_name gre), greAvail gre)
862 lookup_ie (IEThingAbs rdr)
863 = do gre <- lookupGreRn rdr
864 let name = gre_name gre
866 NoParent -> return (IEThingAbs name,
868 ParentIs p -> return (IEThingAbs name,
871 lookup_ie ie@(IEThingAll rdr)
872 = do name <- lookupGlobalOccRn rdr
873 let kids = findChildren kids_env name
875 (if (isTyConName name) then addWarn (dodgyExportWarn name)
876 -- This occurs when you export T(..), but
877 -- only import T abstractly, or T is a synonym.
878 else addErr (exportItemErr ie))
880 return (IEThingAll name, AvailTC name (name:kids))
882 lookup_ie ie@(IEThingWith rdr sub_rdrs)
883 = do name <- lookupGlobalOccRn rdr
884 if isUnboundName name
885 then return (IEThingWith name [], AvailTC name [name])
887 let env = mkOccEnv [ (nameOccName s, s)
888 | s <- findChildren kids_env name ]
889 mb_names = map (lookupOccEnv env . rdrNameOcc) sub_rdrs
890 if any isNothing mb_names
891 then do addErr (exportItemErr ie)
892 return (IEThingWith name [], AvailTC name [name])
893 else do let names = catMaybes mb_names
894 optTyFam <- doptM Opt_TypeFamilies
895 when (not optTyFam && any isTyConName names) $
896 addErr (typeItemErr ( head
899 (text "in export list"))
900 return (IEThingWith name names, AvailTC name (name:names))
902 lookup_ie _ = panic "lookup_ie" -- Other cases covered earlier
905 lookup_doc_ie :: IE RdrName -> RnM (IE Name)
906 lookup_doc_ie (IEGroup lev doc) = do rn_doc <- rnHsDoc doc
907 return (IEGroup lev rn_doc)
908 lookup_doc_ie (IEDoc doc) = do rn_doc <- rnHsDoc doc
909 return (IEDoc rn_doc)
910 lookup_doc_ie (IEDocNamed str) = return (IEDocNamed str)
911 lookup_doc_ie _ = panic "lookup_doc_ie" -- Other cases covered earlier
914 isDoc :: IE RdrName -> Bool
915 isDoc (IEDoc _) = True
916 isDoc (IEDocNamed _) = True
917 isDoc (IEGroup _ _) = True
920 -------------------------------
921 isModuleExported :: Bool -> ModuleName -> GlobalRdrElt -> Bool
922 -- True if the thing is in scope *both* unqualified, *and* with qualifier M
923 isModuleExported implicit_prelude mod (GRE { gre_name = name, gre_prov = prov })
924 | implicit_prelude && isBuiltInSyntax name = False
925 -- Optimisation: filter out names for built-in syntax
926 -- They just clutter up the environment (esp tuples), and the parser
927 -- will generate Exact RdrNames for them, so the cluttered
928 -- envt is no use. To avoid doing this filter all the time,
929 -- we use -fno-implicit-prelude as a clue that the filter is
930 -- worth while. Really, it's only useful for GHC.Base and GHC.Tuple.
932 -- It's worth doing because it makes the environment smaller for
933 -- every module that imports the Prelude
936 LocalDef -> moduleName (nameModule name) == mod
937 Imported is -> any unQualSpecOK is && any (qualSpecOK mod) is
939 -------------------------------
940 check_occs :: IE RdrName -> ExportOccMap -> [Name] -> RnM ExportOccMap
941 check_occs ie occs names
942 = foldlM check occs names
945 = case lookupOccEnv occs name_occ of
946 Nothing -> return (extendOccEnv occs name_occ (name, ie))
949 | name == name' -- Duplicate export
950 -> do { warn_dup_exports <- doptM Opt_WarnDuplicateExports ;
951 warnIf warn_dup_exports (dupExportWarn name_occ ie ie') ;
954 | otherwise -- Same occ name but different names: an error
955 -> do { global_env <- getGlobalRdrEnv ;
956 addErr (exportClashErr global_env name' name ie' ie) ;
959 name_occ = nameOccName name
962 %*********************************************************
966 %*********************************************************
969 finishDeprecations :: DynFlags -> Maybe DeprecTxt
970 -> TcGblEnv -> RnM TcGblEnv
971 -- (a) Report usasge of deprecated imports
972 -- (b) If the whole module is deprecated, update tcg_deprecs
973 -- All this happens only once per module
974 finishDeprecations dflags mod_deprec tcg_env
975 = do { (eps,hpt) <- getEpsAndHpt
976 ; ifOptM Opt_WarnDeprecations $
977 mapM_ (check hpt (eps_PIT eps)) all_gres
978 -- By this time, typechecking is complete,
979 -- so the PIT is fully populated
981 -- Deal with a module deprecation; it overrides all existing deprecs
982 ; let new_deprecs = case mod_deprec of
983 Just txt -> DeprecAll txt
984 Nothing -> tcg_deprecs tcg_env
985 ; return (tcg_env { tcg_deprecs = new_deprecs }) }
987 used_names = allUses (tcg_dus tcg_env)
988 -- Report on all deprecated uses; hence allUses
989 all_gres = globalRdrEnvElts (tcg_rdr_env tcg_env)
991 check hpt pit gre@(GRE {gre_name = name, gre_prov = Imported (imp_spec:_)})
992 | name `elemNameSet` used_names
993 , Just deprec_txt <- lookupImpDeprec dflags hpt pit gre
994 = addWarnAt (importSpecLoc imp_spec)
995 (sep [ptext (sLit "Deprecated use of") <+>
996 pprNonVarNameSpace (occNameSpace (nameOccName name)) <+>
998 (parens imp_msg) <> colon,
1001 name_mod = nameModule name
1002 imp_mod = importSpecModule imp_spec
1003 imp_msg = ptext (sLit "imported from") <+> ppr imp_mod <> extra
1004 extra | imp_mod == moduleName name_mod = empty
1005 | otherwise = ptext (sLit ", but defined in") <+> ppr name_mod
1007 check _ _ _ = return () -- Local, or not used, or not deprectated
1008 -- The Imported pattern-match: don't deprecate locally defined names
1009 -- For a start, we may be exporting a deprecated thing
1010 -- Also we may use a deprecated thing in the defn of another
1011 -- deprecated things. We may even use a deprecated thing in
1012 -- the defn of a non-deprecated thing, when changing a module's
1015 lookupImpDeprec :: DynFlags -> HomePackageTable -> PackageIfaceTable
1016 -> GlobalRdrElt -> Maybe DeprecTxt
1017 -- The name is definitely imported, so look in HPT, PIT
1018 lookupImpDeprec dflags hpt pit gre
1019 = case lookupIfaceByModule dflags hpt pit (nameModule name) of
1020 Just iface -> mi_dep_fn iface name `mplus` -- Bleat if the thing, *or
1022 ParentIs p -> mi_dep_fn iface p -- its parent*, is deprec'd
1025 Nothing -> Nothing -- See Note [Used names with interface not loaded]
1030 Note [Used names with interface not loaded]
1031 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1032 By now all the interfaces should have been loaded,
1033 because reportDeprecations happens after typechecking.
1034 However, it's still (just) possible to to find a used
1035 Name whose interface hasn't been loaded:
1037 a) It might be a WiredInName; in that case we may not load
1038 its interface (although we could).
1040 b) It might be GHC.Real.fromRational, or GHC.Num.fromInteger
1041 These are seen as "used" by the renamer (if -fno-implicit-prelude)
1042 is on), but the typechecker may discard their uses
1043 if in fact the in-scope fromRational is GHC.Read.fromRational,
1044 (see tcPat.tcOverloadedLit), and the typechecker sees that the type
1045 is fixed, say, to GHC.Base.Float (see Inst.lookupSimpleInst).
1046 In that obscure case it won't force the interface in.
1048 In both cases we simply don't permit deprecations;
1049 this is, after all, wired-in stuff.
1052 %*********************************************************
1056 %*********************************************************
1059 reportUnusedNames :: Maybe [LIE RdrName] -- Export list
1060 -> TcGblEnv -> RnM ()
1061 reportUnusedNames export_decls gbl_env
1062 = do { traceRn ((text "RUN") <+> (ppr (tcg_dus gbl_env)))
1063 ; warnUnusedTopBinds unused_locals
1064 ; warnUnusedModules unused_imp_mods
1065 ; warnUnusedImports unused_imports
1066 ; warnDuplicateImports defined_and_used
1067 ; printMinimalImports minimal_imports }
1069 used_names :: NameSet
1070 used_names = findUses (tcg_dus gbl_env) emptyNameSet
1071 -- NB: currently, if f x = g, we only treat 'g' as used if 'f' is used
1074 -- Collect the defined names from the in-scope environment
1075 defined_names :: [GlobalRdrElt]
1076 defined_names = globalRdrEnvElts (tcg_rdr_env gbl_env)
1078 -- Note that defined_and_used, defined_but_not_used
1079 -- are both [GRE]; that's why we need defined_and_used
1080 -- rather than just used_names
1081 defined_and_used, defined_but_not_used :: [GlobalRdrElt]
1082 (defined_and_used, defined_but_not_used)
1083 = partition (gre_is_used used_names) defined_names
1085 kids_env = mkChildEnv defined_names
1086 -- This is done in mkExports too; duplicated work
1088 gre_is_used :: NameSet -> GlobalRdrElt -> Bool
1089 gre_is_used used_names (GRE {gre_name = name})
1090 = name `elemNameSet` used_names
1091 || any (`elemNameSet` used_names) (findChildren kids_env name)
1092 -- A use of C implies a use of T,
1093 -- if C was brought into scope by T(..) or T(C)
1095 -- Filter out the ones that are
1096 -- (a) defined in this module, and
1097 -- (b) not defined by a 'deriving' clause
1098 -- The latter have an Internal Name, so we can filter them out easily
1099 unused_locals :: [GlobalRdrElt]
1100 unused_locals = filter is_unused_local defined_but_not_used
1101 is_unused_local :: GlobalRdrElt -> Bool
1102 is_unused_local gre = isLocalGRE gre && isExternalName (gre_name gre)
1104 unused_imports :: [GlobalRdrElt]
1105 unused_imports = mapCatMaybes unused_imp defined_but_not_used
1106 unused_imp :: GlobalRdrElt -> Maybe GlobalRdrElt -- Result has trimmed Imported provenances
1107 unused_imp (GRE {gre_prov = LocalDef}) = Nothing
1108 unused_imp gre@(GRE {gre_prov = Imported imp_specs})
1109 | null trimmed_specs = Nothing
1110 | otherwise = Just (gre {gre_prov = Imported trimmed_specs})
1112 trimmed_specs = filter report_if_unused imp_specs
1114 -- To figure out the minimal set of imports, start with the things
1115 -- that are in scope (i.e. in gbl_env). Then just combine them
1116 -- into a bunch of avails, so they are properly grouped
1118 -- BUG WARNING: this does not deal properly with qualified imports!
1119 minimal_imports :: FiniteMap ModuleName AvailEnv
1120 minimal_imports0 = foldr add_expall emptyFM expall_mods
1121 minimal_imports1 = foldr add_name minimal_imports0 defined_and_used
1122 minimal_imports = foldr add_inst_mod minimal_imports1 direct_import_mods
1123 -- The last line makes sure that we retain all direct imports
1124 -- even if we import nothing explicitly.
1125 -- It's not necessarily redundant to import such modules. Consider
1129 -- The import M() is not *necessarily* redundant, even if
1130 -- we suck in no instance decls from M (e.g. it contains
1131 -- no instance decls, or This contains no code). It may be
1132 -- that we import M solely to ensure that M's orphan instance
1133 -- decls (or those in its imports) are visible to people who
1134 -- import This. Sigh.
1135 -- There's really no good way to detect this, so the error message
1136 -- in RnEnv.warnUnusedModules is weakened instead
1138 -- We've carefully preserved the provenance so that we can
1139 -- construct minimal imports that import the name by (one of)
1140 -- the same route(s) as the programmer originally did.
1141 add_name gre@(GRE {gre_prov = Imported (imp_spec:_)}) acc
1142 = addToFM_C plusAvailEnv acc
1143 (importSpecModule imp_spec) (unitAvailEnv (greAvail gre))
1144 add_name _ acc = acc -- Local
1146 -- Modules mentioned as 'module M' in the export list
1147 expall_mods = case export_decls of
1149 Just es -> [m | L _ (IEModuleContents m) <- es]
1151 -- This is really bogus. The idea is that if we see 'module M' in
1152 -- the export list we must retain the import decls that drive it
1153 -- If we aren't careful we might see
1154 -- module A( module M ) where
1157 -- and suppose that N exports everything that M does. Then we
1158 -- must not drop the import of M even though N brings it all into
1161 -- BUG WARNING: 'module M' exports aside, what if M.x is mentioned?!
1163 -- The reason that add_expall is bogus is that it doesn't take
1164 -- qualified imports into account. But it's an improvement.
1165 add_expall mod acc = addToFM_C plusAvailEnv acc mod emptyAvailEnv
1167 add_inst_mod (mod, _) acc
1168 | mod_name `elemFM` acc = acc -- We import something already
1169 | otherwise = addToFM acc mod_name emptyAvailEnv
1171 mod_name = moduleName mod
1172 -- Add an empty collection of imports for a module
1173 -- from which we have sucked only instance decls
1175 imports = tcg_imports gbl_env
1177 direct_import_mods :: [(Module, [(ModuleName, Bool, SrcSpan)])]
1178 -- See the type of the imp_mods for this triple
1179 direct_import_mods = moduleEnvElts (imp_mods imports)
1181 -- unused_imp_mods are the directly-imported modules
1182 -- that are not mentioned in minimal_imports1
1183 -- [Note: not 'minimal_imports', because that includes directly-imported
1184 -- modules even if we use nothing from them; see notes above]
1186 -- BUG WARNING: this code is generally buggy
1187 unused_imp_mods :: [(ModuleName, SrcSpan)]
1188 unused_imp_mods = [(mod_name,loc)
1189 | (mod, xs) <- direct_import_mods,
1190 (_, no_imp, loc) <- xs,
1191 let mod_name = moduleName mod,
1192 not (mod_name `elemFM` minimal_imports1),
1195 -- The not no_imp part is not to complain about
1196 -- import M (), which is an idiom for importing
1197 -- instance declarations
1199 module_unused :: ModuleName -> Bool
1200 module_unused mod = any (((==) mod) . fst) unused_imp_mods
1202 report_if_unused :: ImportSpec -> Bool
1203 -- Do we want to report this as an unused import?
1204 report_if_unused (ImpSpec {is_decl = d, is_item = i})
1205 = not (module_unused (is_mod d)) -- Not if we've already said entire import is unused
1206 && isExplicitItem i -- Only if the import was explicit
1208 ---------------------
1209 warnDuplicateImports :: [GlobalRdrElt] -> RnM ()
1210 -- Given the GREs for names that are used, figure out which imports
1211 -- could be omitted without changing the top-level environment.
1213 -- NB: Given import Foo( T )
1214 -- import qualified Foo
1215 -- we do not report a duplicate import, even though Foo.T is brought
1216 -- into scope by both, because there's nothing you can *omit* without
1217 -- changing the top-level environment. So we complain only if it's
1218 -- explicitly named in both imports or neither.
1220 -- Furthermore, we complain about Foo.T only if
1221 -- there is no complaint about (unqualified) T
1223 warnDuplicateImports gres
1224 = ifOptM Opt_WarnUnusedImports $
1225 sequence_ [ warn name pr
1226 | GRE { gre_name = name, gre_prov = Imported imps } <- gres
1227 , pr <- redundants imps ]
1229 warn name (red_imp, cov_imp)
1230 = addWarnAt (importSpecLoc red_imp)
1231 (vcat [ptext (sLit "Redundant import of:") <+> quotes pp_name,
1232 ptext (sLit "It is also") <+> ppr cov_imp])
1234 pp_name | is_qual red_decl = ppr (is_as red_decl) <> dot <> ppr occ
1235 | otherwise = ppr occ
1236 occ = nameOccName name
1237 red_decl = is_decl red_imp
1239 redundants :: [ImportSpec] -> [(ImportSpec,ImportSpec)]
1240 -- The returned pair is (redundant-import, covering-import)
1242 = [ (red_imp, cov_imp)
1244 , isExplicitItem (is_item red_imp)
1245 -- Complain only about redundant imports
1246 -- mentioned explicitly by the user
1247 , cov_imp <- take 1 (filter (covers red_imp) imps) ]
1248 -- The 'take 1' picks the first offending group
1249 -- for this particular name
1251 -- "red_imp" is a putative redundant import
1252 -- "cov_imp" potentially covers it
1253 -- This test decides whether red_imp could be dropped
1255 -- NOTE: currently the test does not warn about
1258 -- even if the same underlying 'x' is involved, because dropping
1259 -- either import would change the qualified names in scope (M.x, N.x)
1260 -- But if the qualified names aren't used, the import is indeed redundant
1261 -- Sadly we don't know that. Oh well.
1262 covers red_imp@(ImpSpec { is_decl = red_decl })
1263 cov_imp@(ImpSpec { is_decl = cov_decl, is_item = cov_item })
1264 | red_loc == cov_loc
1265 = False -- Ignore diagonal elements
1266 | not (is_as red_decl == is_as cov_decl)
1267 = False -- They bring into scope different qualified names
1268 | not (is_qual red_decl) && is_qual cov_decl
1269 = False -- Covering one doesn't bring unqualified name into scope
1271 = not (isExplicitItem cov_item) -- Redundant one is selective and covering one isn't
1272 || red_later -- or both are explicit; tie-break using red_later
1275 = not cov_selective -- Redundant one is selective and covering one isn't
1276 || red_later -- Both are explicit; tie-break using red_later
1278 = not cov_selective -- Neither import is selective
1279 && (is_mod red_decl == is_mod cov_decl) -- They import the same module
1280 && red_later -- Tie-break
1283 red_loc = importSpecLoc red_imp
1284 cov_loc = importSpecLoc cov_imp
1285 red_later = red_loc > cov_loc
1287 -- ToDo: deal with original imports with 'qualified' and 'as M' clauses
1288 printMinimalImports :: FiniteMap ModuleName AvailEnv -- Minimal imports
1290 printMinimalImports imps
1291 = ifOptM Opt_D_dump_minimal_imports $ do {
1293 mod_ies <- initIfaceTcRn $ mapM to_ies (fmToList imps) ;
1294 this_mod <- getModule ;
1295 rdr_env <- getGlobalRdrEnv ;
1296 dflags <- getDOpts ;
1297 liftIO $ do h <- openFile (mkFilename this_mod) WriteMode
1298 printForUser h (mkPrintUnqualified dflags rdr_env)
1299 (vcat (map ppr_mod_ie mod_ies))
1302 mkFilename this_mod = moduleNameString (moduleName this_mod) ++ ".imports"
1303 ppr_mod_ie (mod_name, ies)
1304 | mod_name == moduleName pRELUDE
1306 | null ies -- Nothing except instances comes from here
1307 = ptext (sLit "import") <+> ppr mod_name <> ptext (sLit "() -- Instances only")
1309 = ptext (sLit "import") <+> ppr mod_name <>
1310 parens (fsep (punctuate comma (map ppr ies)))
1312 to_ies (mod, avail_env) = do ies <- mapM to_ie (availEnvElts avail_env)
1315 to_ie :: AvailInfo -> IfG (IE Name)
1316 -- The main trick here is that if we're importing all the constructors
1317 -- we want to say "T(..)", but if we're importing only a subset we want
1318 -- to say "T(A,B,C)". So we have to find out what the module exports.
1319 to_ie (Avail n) = return (IEVar n)
1320 to_ie (AvailTC n [m]) = ASSERT( n==m )
1321 return (IEThingAbs n)
1322 to_ie (AvailTC n ns) = do
1323 iface <- loadSysInterface doc n_mod
1324 case [xs | (m,as) <- mi_exports iface,
1327 x == nameOccName n] of
1328 [xs] | all_used xs -> return (IEThingAll n)
1329 | otherwise -> return (IEThingWith n (filter (/= n) ns))
1330 other -> pprTrace "to_ie" (ppr n <+> ppr n_mod <+> ppr other) $
1333 all_used avail_occs = all (`elem` map nameOccName ns) avail_occs
1334 doc = text "Compute minimal imports from" <+> ppr n
1335 n_mod = nameModule n
1339 %************************************************************************
1343 %************************************************************************
1346 badImportItemErr :: ModIface -> ImpDeclSpec -> IE RdrName -> SDoc
1347 badImportItemErr iface decl_spec ie
1348 = sep [ptext (sLit "Module"), quotes (ppr (is_mod decl_spec)), source_import,
1349 ptext (sLit "does not export"), quotes (ppr ie)]
1351 source_import | mi_boot iface = ptext (sLit "(hi-boot interface)")
1354 illegalImportItemErr :: SDoc
1355 illegalImportItemErr = ptext (sLit "Illegal import item")
1357 dodgyImportWarn :: RdrName -> SDoc
1358 dodgyImportWarn item = dodgyMsg (ptext (sLit "import")) item
1359 dodgyExportWarn :: Name -> SDoc
1360 dodgyExportWarn item = dodgyMsg (ptext (sLit "export")) item
1362 dodgyMsg :: OutputableBndr n => SDoc -> n -> SDoc
1364 = sep [ ptext (sLit "The") <+> kind <+> ptext (sLit "item") <+> quotes (ppr (IEThingAll tc)),
1365 ptext (sLit "suggests that") <+> quotes (ppr tc) <+> ptext (sLit "has constructors or class methods,"),
1366 ptext (sLit "but it has none") ]
1368 exportItemErr :: IE RdrName -> SDoc
1369 exportItemErr export_item
1370 = sep [ ptext (sLit "The export item") <+> quotes (ppr export_item),
1371 ptext (sLit "attempts to export constructors or class methods that are not visible here") ]
1373 typeItemErr :: Name -> SDoc -> SDoc
1374 typeItemErr name wherestr
1375 = sep [ ptext (sLit "Using 'type' tag on") <+> quotes (ppr name) <+> wherestr,
1376 ptext (sLit "Use -XTypeFamilies to enable this extension") ]
1378 exportClashErr :: GlobalRdrEnv -> Name -> Name -> IE RdrName -> IE RdrName
1380 exportClashErr global_env name1 name2 ie1 ie2
1381 = vcat [ ptext (sLit "Conflicting exports for") <+> quotes (ppr occ) <> colon
1382 , ppr_export ie1' name1'
1383 , ppr_export ie2' name2' ]
1385 occ = nameOccName name1
1386 ppr_export ie name = nest 2 (quotes (ppr ie) <+> ptext (sLit "exports") <+>
1387 quotes (ppr name) <+> pprNameProvenance (get_gre name))
1389 -- get_gre finds a GRE for the Name, so that we can show its provenance
1391 = case lookupGRE_Name global_env name of
1393 [] -> pprPanic "exportClashErr" (ppr name)
1394 get_loc name = nameSrcLoc $ gre_name $ get_gre name
1395 (name1', ie1', name2', ie2') = if get_loc name1 < get_loc name2
1396 then (name1, ie1, name2, ie2)
1397 else (name2, ie2, name1, ie1)
1399 addDupDeclErr :: [Name] -> TcRn ()
1401 = panic "addDupDeclErr: empty list"
1402 addDupDeclErr names@(name : _)
1403 = addErrAt (getSrcSpan (last sorted_names)) $
1404 -- Report the error at the later location
1405 vcat [ptext (sLit "Multiple declarations of") <+> quotes (ppr name),
1406 ptext (sLit "Declared at:") <+> vcat (map (ppr . nameSrcLoc) sorted_names)]
1408 sorted_names = sortWith nameSrcLoc names
1410 dupExportWarn :: OccName -> IE RdrName -> IE RdrName -> SDoc
1411 dupExportWarn occ_name ie1 ie2
1412 = hsep [quotes (ppr occ_name),
1413 ptext (sLit "is exported by"), quotes (ppr ie1),
1414 ptext (sLit "and"), quotes (ppr ie2)]
1416 dupModuleExport :: ModuleName -> SDoc
1418 = hsep [ptext (sLit "Duplicate"),
1419 quotes (ptext (sLit "Module") <+> ppr mod),
1420 ptext (sLit "in export list")]
1422 moduleNotImported :: ModuleName -> SDoc
1423 moduleNotImported mod
1424 = ptext (sLit "The export item `module") <+> ppr mod <>
1425 ptext (sLit "' is not imported")
1427 nullModuleExport :: ModuleName -> SDoc
1428 nullModuleExport mod
1429 = ptext (sLit "The export item `module") <+> ppr mod <> ptext (sLit "' exports nothing")
1431 moduleDeprec :: ModuleName -> DeprecTxt -> SDoc
1432 moduleDeprec mod txt
1433 = sep [ ptext (sLit "Module") <+> quotes (ppr mod) <+> ptext (sLit "is deprecated:"),
1436 implicitPreludeWarn :: SDoc
1438 = ptext (sLit "Module `Prelude' implicitly imported")