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, finishWarnings,
13 #include "HsVersions.h"
17 import TcEnv ( isBrackStage )
19 import RnHsDoc ( rnHsDoc )
20 import IfaceEnv ( ifaceExportNames )
21 import LoadIface ( loadSrcInterface, loadSysInterface )
22 import TcRnMonad hiding (LIE)
37 import BasicTypes ( WarningTxt(..) )
38 import DriverPhases ( isHsBoot )
42 import Data.List ( partition, concatMap, (\\), delete )
43 import IO ( openFile, IOMode(..) )
44 import Monad ( when, mplus )
49 %************************************************************************
53 %************************************************************************
56 rnImports :: [LImportDecl RdrName]
57 -> RnM ([LImportDecl Name], GlobalRdrEnv, ImportAvails,AnyHpcUsage)
60 -- PROCESS IMPORT DECLS
61 -- Do the non {- SOURCE -} ones first, so that we get a helpful
62 -- warning for {- SOURCE -} ones that are unnecessary
63 = do this_mod <- getModule
64 implicit_prelude <- doptM Opt_ImplicitPrelude
65 let prel_imports = mkPrelImports this_mod implicit_prelude imports
66 (source, ordinary) = partition is_source_import imports
67 is_source_import (L _ (ImportDecl _ _ is_boot _ _ _)) = is_boot
69 ifOptM Opt_WarnImplicitPrelude (
70 when (notNull prel_imports) $ addWarn (implicitPreludeWarn)
73 stuff1 <- mapM (rnImportDecl this_mod) (prel_imports ++ ordinary)
74 stuff2 <- mapM (rnImportDecl this_mod) source
75 let (decls, rdr_env, imp_avails,hpc_usage) = combine (stuff1 ++ stuff2)
76 return (decls, rdr_env, imp_avails,hpc_usage)
79 combine :: [(LImportDecl Name, GlobalRdrEnv, ImportAvails,AnyHpcUsage)]
80 -> ([LImportDecl Name], GlobalRdrEnv, ImportAvails,AnyHpcUsage)
81 combine = foldr plus ([], emptyGlobalRdrEnv, emptyImportAvails,False)
82 where plus (decl, gbl_env1, imp_avails1,hpc_usage1)
83 (decls, gbl_env2, imp_avails2,hpc_usage2)
85 gbl_env1 `plusGlobalRdrEnv` gbl_env2,
86 imp_avails1 `plusImportAvails` imp_avails2,
87 hpc_usage1 || hpc_usage2)
89 mkPrelImports :: Module -> Bool -> [LImportDecl RdrName] -> [LImportDecl RdrName]
90 -- Consruct the implicit declaration "import Prelude" (or not)
92 -- NB: opt_NoImplicitPrelude is slightly different to import Prelude ();
93 -- because the former doesn't even look at Prelude.hi for instance
94 -- declarations, whereas the latter does.
95 mkPrelImports this_mod implicit_prelude import_decls
97 || explicit_prelude_import
98 || not implicit_prelude
100 | otherwise = [preludeImportDecl]
102 explicit_prelude_import
103 = notNull [ () | L _ (ImportDecl mod Nothing _ _ _ _) <- import_decls,
104 unLoc mod == pRELUDE_NAME ]
106 preludeImportDecl :: LImportDecl RdrName
109 ImportDecl (L loc pRELUDE_NAME)
110 Nothing {- no specific package -}
111 False {- Not a boot interface -}
112 False {- Not qualified -}
113 Nothing {- No "as" -}
114 Nothing {- No import list -}
116 loc = mkGeneralSrcSpan (fsLit "Implicit import declaration")
119 rnImportDecl :: Module
120 -> LImportDecl RdrName
121 -> RnM (LImportDecl Name, GlobalRdrEnv, ImportAvails,AnyHpcUsage)
123 rnImportDecl this_mod (L loc (ImportDecl loc_imp_mod_name mb_pkg want_boot
124 qual_only as_mod imp_details))
128 when (isJust mb_pkg) $ do
129 pkg_imports <- doptM Opt_PackageImports
130 when (not pkg_imports) $ addErr packageImportErr
132 -- If there's an error in loadInterface, (e.g. interface
133 -- file not found) we get lots of spurious errors from 'filterImports'
135 imp_mod_name = unLoc loc_imp_mod_name
136 doc = ppr imp_mod_name <+> ptext (sLit "is directly imported")
138 iface <- loadSrcInterface doc imp_mod_name want_boot mb_pkg
140 -- Compiler sanity check: if the import didn't say
141 -- {-# SOURCE #-} we should not get a hi-boot file
142 WARN( not want_boot && mi_boot iface, ppr imp_mod_name ) (do
144 -- Issue a user warning for a redundant {- SOURCE -} import
145 -- NB that we arrange to read all the ordinary imports before
146 -- any of the {- SOURCE -} imports.
148 -- in --make and GHCi, the compilation manager checks for this,
149 -- and indeed we shouldn't do it here because the existence of
150 -- the non-boot module depends on the compilation order, which
151 -- is not deterministic. The hs-boot test can show this up.
153 warnIf (want_boot && not (mi_boot iface) && isOneShot (ghcMode dflags))
154 (warnRedundantSourceImport imp_mod_name)
157 imp_mod = mi_module iface
158 warns = mi_warns iface
159 orph_iface = mi_orphan iface
160 has_finsts = mi_finsts iface
163 filtered_exports = filter not_this_mod (mi_exports iface)
164 not_this_mod (mod,_) = mod /= this_mod
165 -- If the module exports anything defined in this module, just
166 -- ignore it. Reason: otherwise it looks as if there are two
167 -- local definition sites for the thing, and an error gets
168 -- reported. Easiest thing is just to filter them out up
169 -- front. This situation only arises if a module imports
170 -- itself, or another module that imported it. (Necessarily,
171 -- this invoves a loop.)
173 -- Tiresome consequence: if you say
178 -- module B( AType ) where
179 -- import {-# SOURCE #-} A( AType )
181 -- then you'll get a 'B does not export AType' message. Oh well.
183 qual_mod_name = case as_mod of
184 Nothing -> imp_mod_name
185 Just another_name -> another_name
186 imp_spec = ImpDeclSpec { is_mod = imp_mod_name, is_qual = qual_only,
187 is_dloc = loc, is_as = qual_mod_name }
190 -- Get the total exports from this module
191 total_avails <- ifaceExportNames filtered_exports
193 -- filter the imports according to the import declaration
194 (new_imp_details, gbl_env) <-
195 filterImports iface imp_spec imp_details total_avails
200 -- Compute new transitive dependencies
202 orphans | orph_iface = ASSERT( not (imp_mod `elem` dep_orphs deps) )
203 imp_mod : dep_orphs deps
204 | otherwise = dep_orphs deps
206 finsts | has_finsts = ASSERT( not (imp_mod `elem` dep_finsts deps) )
207 imp_mod : dep_finsts deps
208 | otherwise = dep_finsts deps
210 pkg = modulePackageId (mi_module iface)
212 (dependent_mods, dependent_pkgs)
213 | pkg == thisPackage dflags =
214 -- Imported module is from the home package
215 -- Take its dependent modules and add imp_mod itself
216 -- Take its dependent packages unchanged
218 -- NB: (dep_mods deps) might include a hi-boot file
219 -- for the module being compiled, CM. Do *not* filter
220 -- this out (as we used to), because when we've
221 -- finished dealing with the direct imports we want to
222 -- know if any of them depended on CM.hi-boot, in
223 -- which case we should do the hi-boot consistency
224 -- check. See LoadIface.loadHiBootInterface
225 ((imp_mod_name, want_boot) : dep_mods deps, dep_pkgs deps)
228 -- Imported module is from another package
229 -- Dump the dependent modules
230 -- Add the package imp_mod comes from to the dependent packages
231 ASSERT2( not (pkg `elem` dep_pkgs deps), ppr pkg <+> ppr (dep_pkgs deps) )
232 ([], pkg : dep_pkgs deps)
234 -- True <=> import M ()
235 import_all = case imp_details of
236 Just (is_hiding, ls) -> not is_hiding && null ls
239 imports = ImportAvails {
240 imp_mods = unitModuleEnv imp_mod [(qual_mod_name, import_all, loc)],
243 imp_dep_mods = mkModDeps dependent_mods,
244 imp_dep_pkgs = dependent_pkgs
247 -- Complain if we import a deprecated module
248 ifOptM Opt_WarnWarningsDeprecations (
250 WarnAll txt -> addWarn (moduleWarn imp_mod_name txt)
254 let new_imp_decl = L loc (ImportDecl loc_imp_mod_name mb_pkg want_boot
255 qual_only as_mod new_imp_details)
257 return (new_imp_decl, gbl_env, imports, mi_hpc iface)
260 warnRedundantSourceImport :: ModuleName -> SDoc
261 warnRedundantSourceImport mod_name
262 = ptext (sLit "Unnecessary {-# SOURCE #-} in the import of module")
263 <+> quotes (ppr mod_name)
267 %************************************************************************
269 importsFromLocalDecls
271 %************************************************************************
273 From the top-level declarations of this module produce
274 * the lexical environment
276 created by its bindings.
278 Note [Top-level Names in Template Haskell decl quotes]
279 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
280 Consider a Template Haskell declaration quotation like this:
283 When renaming the declarations inside [d| ...|], we treat the
284 top level binders specially in two ways
286 1. We give them an Internal name, not (as usual) an External one.
287 Otherwise the NameCache gets confused by a second allocation of
288 M.f. (We used to invent a fake module ThFake to avoid this, but
289 that had other problems, notably in getting the correct answer for
290 nameIsLocalOrFrom in lookupFixity. So we now leave tcg_module
293 2. We make them *shadow* the outer bindings. If we don't do that,
294 we'll get a complaint when extending the GlobalRdrEnv, saying that
295 there are two bindings for 'f'.
297 This shadowing applies even if the binding for 'f' is in a
298 where-clause, and hence is in the *local* RdrEnv not the *global*
301 We find out whether we are inside a [d| ... |] by testing the TH
302 stage. This is a slight hack, because the stage field was really meant for
303 the type checker, and here we are not interested in the fields of Brack,
304 hence the error thunks in thRnBrack.
307 extendGlobalRdrEnvRn :: [AvailInfo]
309 -> RnM (TcGblEnv, TcLclEnv)
310 -- Updates both the GlobalRdrEnv and the FixityEnv
311 -- We return a new TcLclEnv only becuase we might have to
312 -- delete some bindings from it;
313 -- see Note [Top-level Names in Template Haskell decl quotes]
315 extendGlobalRdrEnvRn avails new_fixities
316 = do { (gbl_env, lcl_env) <- getEnvs
318 ; let rdr_env = tcg_rdr_env gbl_env
319 fix_env = tcg_fix_env gbl_env
321 -- Delete new_occs from global and local envs
322 -- If we are in a TemplateHaskell decl bracket,
323 -- we are going to shadow them
324 -- See Note [Top-level Names in Template Haskell decl quotes]
325 shadowP = isBrackStage stage
326 new_occs = map (nameOccName . gre_name) gres
327 rdr_env1 = hideSomeUnquals rdr_env new_occs
328 lcl_env1 = lcl_env { tcl_rdr = delListFromOccEnv (tcl_rdr lcl_env) new_occs }
329 (rdr_env2, lcl_env2) | shadowP = (rdr_env1, lcl_env1)
330 | otherwise = (rdr_env, lcl_env)
332 rdr_env3 = foldl extendGlobalRdrEnv rdr_env2 gres
333 fix_env' = foldl extend_fix_env fix_env gres
334 (rdr_env', dups) = findLocalDupsRdrEnv rdr_env3 new_occs
336 gbl_env' = gbl_env { tcg_rdr_env = rdr_env', tcg_fix_env = fix_env' }
338 ; mapM_ addDupDeclErr dups
340 ; traceRn (text "extendGlobalRdrEnvRn" <+> (ppr new_fixities $$ ppr fix_env $$ ppr fix_env'))
341 ; return (gbl_env', lcl_env2) }
343 gres = gresFromAvails LocalDef avails
345 -- If there is a fixity decl for the gre, add it to the fixity env
346 extend_fix_env fix_env gre
347 | Just (L _ fi) <- lookupFsEnv new_fixities (occNameFS occ)
348 = extendNameEnv fix_env name (FixItem occ fi)
353 occ = nameOccName name
356 @getLocalDeclBinders@ returns the names for an @HsDecl@. It's
357 used for source code.
359 *** See "THE NAMING STORY" in HsDecls ****
361 Instances of type families
362 ~~~~~~~~~~~~~~~~~~~~~~~~~~
363 Indexed data/newtype instances contain data constructors that we need to
364 collect, too. Moreover, we need to descend into the data/newtypes instances
365 of associated families.
367 We need to be careful with the handling of the type constructor of each type
368 instance as the family constructor is already defined, and we want to avoid
369 raising a duplicate declaration error. So, we make a new name for it, but
370 don't return it in the 'AvailInfo'.
373 getLocalNonValBinders :: HsGroup RdrName -> RnM [AvailInfo]
374 -- Get all the top-level binders bound the group *except*
375 -- for value bindings, which are treated separately
376 -- Specificaly we return AvailInfo for
381 -- (in hs-boot files) value signatures
383 getLocalNonValBinders group
384 = do { gbl_env <- getGblEnv
385 ; get_local_binders gbl_env group }
387 get_local_binders :: TcGblEnv -> HsGroup RdrName -> RnM [GenAvailInfo Name]
388 get_local_binders gbl_env (HsGroup {hs_valds = ValBindsIn _ val_sigs,
389 hs_tyclds = tycl_decls,
390 hs_instds = inst_decls,
391 hs_fords = foreign_decls })
392 = do { tc_names_s <- mapM new_tc tycl_decls
393 ; at_names_s <- mapM inst_ats inst_decls
394 ; val_names <- mapM new_simple val_bndrs
395 ; return (val_names ++ tc_names_s ++ concat at_names_s) }
397 mod = tcg_mod gbl_env
398 is_hs_boot = isHsBoot (tcg_src gbl_env) ;
400 for_hs_bndrs :: [Located RdrName]
401 for_hs_bndrs = [nm | L _ (ForeignImport nm _ _) <- foreign_decls]
403 -- In a hs-boot file, the value binders come from the
404 -- *signatures*, and there should be no foreign binders
405 val_bndrs :: [Located RdrName]
406 val_bndrs | is_hs_boot = [nm | L _ (TypeSig nm _) <- val_sigs]
407 | otherwise = for_hs_bndrs
409 new_simple :: Located RdrName -> RnM (GenAvailInfo Name)
410 new_simple rdr_name = do
411 nm <- newTopSrcBinder mod rdr_name
415 | isFamInstDecl (unLoc tc_decl)
416 = do { main_name <- lookupFamInstDeclBndr mod main_rdr
417 ; sub_names <- mapM (newTopSrcBinder mod) sub_rdrs
418 ; return (AvailTC main_name sub_names) }
419 -- main_name is not bound here!
421 = do { main_name <- newTopSrcBinder mod main_rdr
422 ; sub_names <- mapM (newTopSrcBinder mod) sub_rdrs
423 ; return (AvailTC main_name (main_name : sub_names)) }
425 (main_rdr : sub_rdrs) = tyClDeclNames (unLoc tc_decl)
428 = mapM new_tc (instDeclATs (unLoc inst_decl))
430 get_local_binders _ g = pprPanic "get_local_binders" (ppr g)
434 %************************************************************************
436 \subsection{Filtering imports}
438 %************************************************************************
440 @filterImports@ takes the @ExportEnv@ telling what the imported module makes
441 available, and filters it through the import spec (if any).
444 filterImports :: ModIface
445 -> ImpDeclSpec -- The span for the entire import decl
446 -> Maybe (Bool, [LIE RdrName]) -- Import spec; True => hiding
447 -> [AvailInfo] -- What's available
448 -> RnM (Maybe (Bool, [LIE Name]), -- Import spec w/ Names
449 GlobalRdrEnv) -- Same again, but in GRE form
450 filterImports _ decl_spec Nothing all_avails
451 = return (Nothing, mkGlobalRdrEnv (gresFromAvails prov all_avails))
453 prov = Imported [ImpSpec { is_decl = decl_spec, is_item = ImpAll }]
456 filterImports iface decl_spec (Just (want_hiding, import_items)) all_avails
457 = do -- check for errors, convert RdrNames to Names
458 opt_typeFamilies <- doptM Opt_TypeFamilies
459 items1 <- mapM (lookup_lie opt_typeFamilies) import_items
461 let items2 :: [(LIE Name, AvailInfo)]
462 items2 = concat items1
463 -- NB the AvailInfo may have duplicates, and several items
464 -- for the same parent; e.g N(x) and N(y)
466 names = availsToNameSet (map snd items2)
467 keep n = not (n `elemNameSet` names)
468 pruned_avails = filterAvails keep all_avails
469 hiding_prov = Imported [ImpSpec { is_decl = decl_spec, is_item = ImpAll }]
471 gres | want_hiding = gresFromAvails hiding_prov pruned_avails
472 | otherwise = concatMap (gresFromIE decl_spec) items2
474 return (Just (want_hiding, map fst items2), mkGlobalRdrEnv gres)
476 -- This environment is how we map names mentioned in the import
477 -- list to the actual Name they correspond to, and the name family
478 -- that the Name belongs to (the AvailInfo). The situation is
479 -- complicated by associated families, which introduce a three-level
480 -- hierachy, where class = grand parent, assoc family = parent, and
481 -- data constructors = children. The occ_env entries for associated
482 -- families needs to capture all this information; hence, we have the
483 -- third component of the environment that gives the class name (=
484 -- grand parent) in case of associated families.
486 -- This env will have entries for data constructors too,
487 -- they won't make any difference because naked entities like T
488 -- in an import list map to TcOccs, not VarOccs.
489 occ_env :: OccEnv (Name, -- the name
490 AvailInfo, -- the export item providing the name
491 Maybe Name) -- the parent of associated types
492 occ_env = mkOccEnv_C combine [ (nameOccName n, (n, a, Nothing))
493 | a <- all_avails, n <- availNames a]
495 -- we know that (1) there are at most entries for one name, (2) their
496 -- first component is identical, (3) they are for tys/cls, and (4) one
497 -- entry has the name in its parent position (the other doesn't)
498 combine (name, AvailTC p1 subs1, Nothing)
499 (_ , AvailTC p2 subs2, Nothing)
501 (parent, subs) = if p1 == name then (p2, subs1) else (p1, subs2)
503 (name, AvailTC name subs, Just parent)
504 combine x y = pprPanic "filterImports/combine" (ppr x $$ ppr y)
506 lookup_lie :: Bool -> LIE RdrName -> TcRn [(LIE Name, AvailInfo)]
507 lookup_lie opt_typeFamilies (L loc ieRdr)
509 stuff <- setSrcSpan loc $
510 case lookup_ie opt_typeFamilies ieRdr of
511 Failed err -> addErr err >> return []
512 Succeeded a -> return a
513 checkDodgyImport stuff
514 return [ (L loc ie, avail) | (ie,avail) <- stuff ]
516 -- Warn when importing T(..) if T was exported abstractly
517 checkDodgyImport stuff
518 | IEThingAll n <- ieRdr, (_, AvailTC _ [_]):_ <- stuff
519 = ifOptM Opt_WarnDodgyImports (addWarn (dodgyImportWarn n))
520 -- NB. use the RdrName for reporting the warning
524 -- For each import item, we convert its RdrNames to Names,
525 -- and at the same time construct an AvailInfo corresponding
526 -- to what is actually imported by this item.
527 -- Returns Nothing on error.
528 -- We return a list here, because in the case of an import
529 -- item like C, if we are hiding, then C refers to *both* a
530 -- type/class and a data constructor. Moreover, when we import
531 -- data constructors of an associated family, we need separate
532 -- AvailInfos for the data constructors and the family (as they have
533 -- different parents). See the discussion at occ_env.
534 lookup_ie :: Bool -> IE RdrName -> MaybeErr Message [(IE Name,AvailInfo)]
535 lookup_ie opt_typeFamilies ie
536 = let bad_ie = Failed (badImportItemErr iface decl_spec ie)
538 lookup_name rdrName =
539 case lookupOccEnv occ_env (rdrNameOcc rdrName) of
545 (name, avail, _) <- lookup_name n
546 return [(IEVar name, trimAvail avail name)]
549 (name, avail@(AvailTC name2 subs), mb_parent) <- lookup_name tc
551 -- non-associated ty/cls
552 Nothing -> return [(IEThingAll name, avail)]
554 Just parent -> return [(IEThingAll name,
555 AvailTC name2 (subs \\ [name])),
556 (IEThingAll name, AvailTC parent [name])]
559 | want_hiding -- hiding ( C )
560 -- Here the 'C' can be a data constructor
561 -- *or* a type/class, or even both
562 -> let tc_name = lookup_name tc
563 dc_name = lookup_name (setRdrNameSpace tc srcDataName)
565 case catMaybeErr [ tc_name, dc_name ] of
567 names -> return [mkIEThingAbs name | name <- names]
569 -> do nameAvail <- lookup_name tc
570 return [mkIEThingAbs nameAvail]
572 IEThingWith tc ns -> do
573 (name, AvailTC _ subnames, mb_parent) <- lookup_name tc
575 env = mkOccEnv [(nameOccName s, s) | s <- subnames]
576 mb_children = map (lookupOccEnv env . rdrNameOcc) ns
577 children <- if any isNothing mb_children
579 else return (catMaybes mb_children)
580 -- check for proper import of type families
581 when (not opt_typeFamilies && any isTyConName children) $
582 Failed (typeItemErr (head . filter isTyConName $ children)
583 (text "in import list"))
585 -- non-associated ty/cls
586 Nothing -> return [(IEThingWith name children,
587 AvailTC name (name:children))]
589 Just parent -> return [(IEThingWith name children,
590 AvailTC name children),
591 (IEThingWith name children,
592 AvailTC parent [name])]
594 _other -> Failed illegalImportItemErr
595 -- could be IEModuleContents, IEGroup, IEDoc, IEDocNamed
599 mkIEThingAbs (n, av, Nothing ) = (IEThingAbs n, trimAvail av n)
600 mkIEThingAbs (n, _, Just parent) = (IEThingAbs n, AvailTC parent [n])
603 catMaybeErr :: [MaybeErr err a] -> [a]
604 catMaybeErr ms = [ a | Succeeded a <- ms ]
607 %************************************************************************
611 %************************************************************************
614 -- | make a 'GlobalRdrEnv' where all the elements point to the same
615 -- import declaration (useful for "hiding" imports, or imports with
617 gresFromAvails :: Provenance -> [AvailInfo] -> [GlobalRdrElt]
618 gresFromAvails prov avails
619 = concatMap (gresFromAvail (const prov)) avails
621 gresFromAvail :: (Name -> Provenance) -> AvailInfo -> [GlobalRdrElt]
622 gresFromAvail prov_fn avail
623 = [ GRE {gre_name = n,
624 gre_par = availParent n avail,
625 gre_prov = prov_fn n}
626 | n <- availNames avail ]
628 greAvail :: GlobalRdrElt -> AvailInfo
629 greAvail gre = mkUnitAvail (gre_name gre) (gre_par gre)
631 mkUnitAvail :: Name -> Parent -> AvailInfo
632 mkUnitAvail me (ParentIs p) = AvailTC p [me]
633 mkUnitAvail me NoParent | isTyConName me = AvailTC me [me]
634 | otherwise = Avail me
636 plusAvail :: GenAvailInfo Name -> GenAvailInfo Name -> GenAvailInfo Name
637 plusAvail (Avail n1) (Avail _) = Avail n1
638 plusAvail (AvailTC _ ns1) (AvailTC n2 ns2) = AvailTC n2 (ns1 `unionLists` ns2)
639 plusAvail a1 a2 = pprPanic "RnEnv.plusAvail" (hsep [ppr a1,ppr a2])
641 availParent :: Name -> AvailInfo -> Parent
642 availParent _ (Avail _) = NoParent
643 availParent n (AvailTC m _) | n == m = NoParent
644 | otherwise = ParentIs m
646 trimAvail :: AvailInfo -> Name -> AvailInfo
647 trimAvail (Avail n) _ = Avail n
648 trimAvail (AvailTC n ns) m = ASSERT( m `elem` ns) AvailTC n [m]
650 -- | filters 'AvailInfo's by the given predicate
651 filterAvails :: (Name -> Bool) -> [AvailInfo] -> [AvailInfo]
652 filterAvails keep avails = foldr (filterAvail keep) [] avails
654 -- | filters an 'AvailInfo' by the given predicate
655 filterAvail :: (Name -> Bool) -> AvailInfo -> [AvailInfo] -> [AvailInfo]
656 filterAvail keep ie rest =
658 Avail n | keep n -> ie : rest
661 let left = filter keep ns in
662 if null left then rest else AvailTC tc left : rest
664 -- | Given an import\/export spec, construct the appropriate 'GlobalRdrElt's.
665 gresFromIE :: ImpDeclSpec -> (LIE Name, AvailInfo) -> [GlobalRdrElt]
666 gresFromIE decl_spec (L loc ie, avail)
667 = gresFromAvail prov_fn avail
669 is_explicit = case ie of
670 IEThingAll name -> \n -> n == name
672 prov_fn name = Imported [imp_spec]
674 imp_spec = ImpSpec { is_decl = decl_spec, is_item = item_spec }
675 item_spec = ImpSome { is_explicit = is_explicit name, is_iloc = loc }
677 mkChildEnv :: [GlobalRdrElt] -> NameEnv [Name]
678 mkChildEnv gres = foldr add emptyNameEnv gres
680 add (GRE { gre_name = n, gre_par = ParentIs p }) env = extendNameEnv_C (++) env p [n]
683 findChildren :: NameEnv [Name] -> Name -> [Name]
684 findChildren env n = lookupNameEnv env n `orElse` []
687 ---------------------------------------
690 All this AvailEnv stuff is hardly used; only in a very small
691 part of RnNames. Todo: remove?
692 ---------------------------------------
695 type AvailEnv = NameEnv AvailInfo -- Maps a Name to the AvailInfo that contains it
697 emptyAvailEnv :: AvailEnv
698 emptyAvailEnv = emptyNameEnv
700 unitAvailEnv :: AvailInfo -> AvailEnv
701 unitAvailEnv a = unitNameEnv (availName a) a
703 plusAvailEnv :: AvailEnv -> AvailEnv -> AvailEnv
704 plusAvailEnv = plusNameEnv_C plusAvail
706 availEnvElts :: AvailEnv -> [AvailInfo]
707 availEnvElts = nameEnvElts
709 addAvail :: AvailEnv -> AvailInfo -> AvailEnv
710 addAvail avails avail = extendNameEnv_C plusAvail avails (availName avail) avail
712 mkAvailEnv :: [AvailInfo] -> AvailEnv
713 -- 'avails' may have several items with the same availName
714 -- E.g import Ix( Ix(..), index )
715 -- will give Ix(Ix,index,range) and Ix(index)
716 -- We want to combine these; addAvail does that
717 mkAvailEnv avails = foldl addAvail emptyAvailEnv avails
719 -- After combining the avails, we need to ensure that the parent name is the
720 -- first entry in the list of subnames, if it is included at all. (Subsequent
721 -- functions rely on that.)
722 normaliseAvail :: AvailInfo -> AvailInfo
723 normaliseAvail avail@(Avail _) = avail
724 normaliseAvail (AvailTC name subs) = AvailTC name subs'
726 subs' = if name `elem` subs then name : (delete name subs) else subs
728 -- | combines 'AvailInfo's from the same family
729 nubAvails :: [AvailInfo] -> [AvailInfo]
730 nubAvails avails = map normaliseAvail . nameEnvElts . mkAvailEnv $ avails
734 %************************************************************************
736 \subsection{Export list processing}
738 %************************************************************************
740 Processing the export list.
742 You might think that we should record things that appear in the export
743 list as ``occurrences'' (using @addOccurrenceName@), but you'd be
744 wrong. We do check (here) that they are in scope, but there is no
745 need to slurp in their actual declaration (which is what
746 @addOccurrenceName@ forces).
748 Indeed, doing so would big trouble when compiling @PrelBase@, because
749 it re-exports @GHC@, which includes @takeMVar#@, whose type includes
750 @ConcBase.StateAndSynchVar#@, and so on...
753 type ExportAccum -- The type of the accumulating parameter of
754 -- the main worker function in rnExports
755 = ([LIE Name], -- Export items with Names
756 ExportOccMap, -- Tracks exported occurrence names
757 [AvailInfo]) -- The accumulated exported stuff
760 emptyExportAccum :: ExportAccum
761 emptyExportAccum = ([], emptyOccEnv, [])
763 type ExportOccMap = OccEnv (Name, IE RdrName)
764 -- Tracks what a particular exported OccName
765 -- in an export list refers to, and which item
766 -- it came from. It's illegal to export two distinct things
767 -- that have the same occurrence name
769 rnExports :: Bool -- False => no 'module M(..) where' header at all
770 -> Maybe [LIE RdrName] -- Nothing => no explicit export list
774 -- Complains if two distinct exports have same OccName
775 -- Warns about identical exports.
776 -- Complains about exports items not in scope
778 rnExports explicit_mod exports
779 tcg_env@(TcGblEnv { tcg_mod = this_mod,
780 tcg_rdr_env = rdr_env,
781 tcg_imports = imports })
783 -- If the module header is omitted altogether, then behave
784 -- as if the user had written "module Main(main) where..."
785 -- EXCEPT in interactive mode, when we behave as if he had
786 -- written "module Main where ..."
787 -- Reason: don't want to complain about 'main' not in scope
788 -- in interactive mode
791 | explicit_mod = exports
792 | ghcLink dflags == LinkInMemory = Nothing
793 | otherwise = Just ([noLoc (IEVar main_RDR_Unqual)])
794 -- ToDo: the 'noLoc' here is unhelpful if 'main'
795 -- turns out to be out of scope
797 ; (rn_exports, avails) <- exports_from_avail real_exports rdr_env imports this_mod
798 ; let final_avails = nubAvails avails -- Combine families
800 ; return (tcg_env { tcg_exports = final_avails,
801 tcg_rn_exports = case tcg_rn_exports tcg_env of
803 Just _ -> rn_exports,
804 tcg_dus = tcg_dus tcg_env `plusDU`
805 usesOnly (availsToNameSet final_avails) }) }
808 exports_from_avail :: Maybe [LIE RdrName]
809 -- Nothing => no explicit export list
813 -> RnM (Maybe [LIE Name], [AvailInfo])
815 exports_from_avail Nothing rdr_env _imports _this_mod
816 = -- The same as (module M) where M is the current module name,
817 -- so that's how we handle it.
819 avails = [ greAvail gre | gre <- globalRdrEnvElts rdr_env,
822 return (Nothing, avails)
824 exports_from_avail (Just rdr_items) rdr_env imports this_mod
825 = do (ie_names, _, exports) <- foldlM do_litem emptyExportAccum rdr_items
827 return (Just ie_names, exports)
829 do_litem :: ExportAccum -> LIE RdrName -> RnM ExportAccum
830 do_litem acc lie = setSrcSpan (getLoc lie) (exports_from_item acc lie)
832 kids_env :: NameEnv [Name] -- Maps a parent to its in-scope children
833 kids_env = mkChildEnv (globalRdrEnvElts rdr_env)
835 imported_modules = [ qual_name
836 | xs <- moduleEnvElts $ imp_mods imports,
837 (qual_name, _, _) <- xs ]
839 exports_from_item :: ExportAccum -> LIE RdrName -> RnM ExportAccum
840 exports_from_item acc@(ie_names, occs, exports)
841 (L loc ie@(IEModuleContents mod))
842 | let earlier_mods = [ mod | (L _ (IEModuleContents mod)) <- ie_names ]
843 , mod `elem` earlier_mods -- Duplicate export of M
844 = do { warn_dup_exports <- doptM Opt_WarnDuplicateExports ;
845 warnIf warn_dup_exports (dupModuleExport mod) ;
849 = do { implicit_prelude <- doptM Opt_ImplicitPrelude
850 ; let { exportValid = (mod `elem` imported_modules)
851 || (moduleName this_mod == mod)
852 ; gres = filter (isModuleExported implicit_prelude mod)
853 (globalRdrEnvElts rdr_env)
856 ; checkErr exportValid (moduleNotImported mod)
857 ; warnIf (exportValid && null gres) (nullModuleExport mod)
859 ; occs' <- check_occs ie occs (map gre_name gres)
860 -- This check_occs not only finds conflicts
861 -- between this item and others, but also
862 -- internally within this item. That is, if
863 -- 'M.x' is in scope in several ways, we'll have
864 -- several members of mod_avails with the same
866 ; return (L loc (IEModuleContents mod) : ie_names,
867 occs', map greAvail gres ++ exports) }
869 exports_from_item acc@(lie_names, occs, exports) (L loc ie)
871 = do new_ie <- lookup_doc_ie ie
872 return (L loc new_ie : lie_names, occs, exports)
875 = do (new_ie, avail) <- lookup_ie ie
876 if isUnboundName (ieName new_ie)
877 then return acc -- Avoid error cascade
880 occs' <- check_occs ie occs (availNames avail)
882 return (L loc new_ie : lie_names, occs', avail : exports)
885 lookup_ie :: IE RdrName -> RnM (IE Name, AvailInfo)
886 lookup_ie (IEVar rdr)
887 = do gre <- lookupGreRn rdr
888 return (IEVar (gre_name gre), greAvail gre)
890 lookup_ie (IEThingAbs rdr)
891 = do gre <- lookupGreRn rdr
892 let name = gre_name gre
894 NoParent -> return (IEThingAbs name,
896 ParentIs p -> return (IEThingAbs name,
899 lookup_ie ie@(IEThingAll rdr)
900 = do name <- lookupGlobalOccRn rdr
901 let kids = findChildren kids_env name
903 (if (isTyConName name) then addWarn (dodgyExportWarn name)
904 -- This occurs when you export T(..), but
905 -- only import T abstractly, or T is a synonym.
906 else addErr (exportItemErr ie))
908 return (IEThingAll name, AvailTC name (name:kids))
910 lookup_ie ie@(IEThingWith rdr sub_rdrs)
911 = do name <- lookupGlobalOccRn rdr
912 if isUnboundName name
913 then return (IEThingWith name [], AvailTC name [name])
915 let env = mkOccEnv [ (nameOccName s, s)
916 | s <- findChildren kids_env name ]
917 mb_names = map (lookupOccEnv env . rdrNameOcc) sub_rdrs
918 if any isNothing mb_names
919 then do addErr (exportItemErr ie)
920 return (IEThingWith name [], AvailTC name [name])
921 else do let names = catMaybes mb_names
922 optTyFam <- doptM Opt_TypeFamilies
923 when (not optTyFam && any isTyConName names) $
924 addErr (typeItemErr ( head
927 (text "in export list"))
928 return (IEThingWith name names, AvailTC name (name:names))
930 lookup_ie _ = panic "lookup_ie" -- Other cases covered earlier
933 lookup_doc_ie :: IE RdrName -> RnM (IE Name)
934 lookup_doc_ie (IEGroup lev doc) = do rn_doc <- rnHsDoc doc
935 return (IEGroup lev rn_doc)
936 lookup_doc_ie (IEDoc doc) = do rn_doc <- rnHsDoc doc
937 return (IEDoc rn_doc)
938 lookup_doc_ie (IEDocNamed str) = return (IEDocNamed str)
939 lookup_doc_ie _ = panic "lookup_doc_ie" -- Other cases covered earlier
942 isDoc :: IE RdrName -> Bool
943 isDoc (IEDoc _) = True
944 isDoc (IEDocNamed _) = True
945 isDoc (IEGroup _ _) = True
948 -------------------------------
949 isModuleExported :: Bool -> ModuleName -> GlobalRdrElt -> Bool
950 -- True if the thing is in scope *both* unqualified, *and* with qualifier M
951 isModuleExported implicit_prelude mod (GRE { gre_name = name, gre_prov = prov })
952 | implicit_prelude && isBuiltInSyntax name = False
953 -- Optimisation: filter out names for built-in syntax
954 -- They just clutter up the environment (esp tuples), and the parser
955 -- will generate Exact RdrNames for them, so the cluttered
956 -- envt is no use. To avoid doing this filter all the time,
957 -- we use -XNoImplicitPrelude as a clue that the filter is
958 -- worth while. Really, it's only useful for GHC.Base and GHC.Tuple.
960 -- It's worth doing because it makes the environment smaller for
961 -- every module that imports the Prelude
964 LocalDef | Just name_mod <- nameModule_maybe name
965 -> moduleName name_mod == mod
967 Imported is -> any unQualSpecOK is && any (qualSpecOK mod) is
969 -------------------------------
970 check_occs :: IE RdrName -> ExportOccMap -> [Name] -> RnM ExportOccMap
971 check_occs ie occs names
972 = foldlM check occs names
975 = case lookupOccEnv occs name_occ of
976 Nothing -> return (extendOccEnv occs name_occ (name, ie))
979 | name == name' -- Duplicate export
980 -> do { warn_dup_exports <- doptM Opt_WarnDuplicateExports ;
981 warnIf warn_dup_exports (dupExportWarn name_occ ie ie') ;
984 | otherwise -- Same occ name but different names: an error
985 -> do { global_env <- getGlobalRdrEnv ;
986 addErr (exportClashErr global_env name' name ie' ie) ;
989 name_occ = nameOccName name
992 %*********************************************************
996 %*********************************************************
999 finishWarnings :: DynFlags -> Maybe WarningTxt
1000 -> TcGblEnv -> RnM TcGblEnv
1001 -- (a) Report usage of imports that are deprecated or have other warnings
1002 -- (b) If the whole module is warned about or deprecated, update tcg_warns
1003 -- All this happens only once per module
1004 finishWarnings dflags mod_warn tcg_env
1005 = do { (eps,hpt) <- getEpsAndHpt
1006 ; ifOptM Opt_WarnWarningsDeprecations $
1007 mapM_ (check hpt (eps_PIT eps)) all_gres
1008 -- By this time, typechecking is complete,
1009 -- so the PIT is fully populated
1011 -- Deal with a module deprecation; it overrides all existing warns
1012 ; let new_warns = case mod_warn of
1013 Just txt -> WarnAll txt
1014 Nothing -> tcg_warns tcg_env
1015 ; return (tcg_env { tcg_warns = new_warns }) }
1017 used_names = allUses (tcg_dus tcg_env)
1018 -- Report on all deprecated uses; hence allUses
1019 all_gres = globalRdrEnvElts (tcg_rdr_env tcg_env)
1021 check hpt pit gre@(GRE {gre_name = name, gre_prov = Imported (imp_spec:_)})
1022 | name `elemNameSet` used_names
1023 , Just deprec_txt <- lookupImpDeprec dflags hpt pit gre
1024 = addWarnAt (importSpecLoc imp_spec)
1025 (sep [ptext (sLit "In the use of") <+>
1026 pprNonVarNameSpace (occNameSpace (nameOccName name)) <+>
1028 (parens imp_msg) <> colon,
1031 name_mod = ASSERT2( isExternalName name, ppr name ) nameModule name
1032 imp_mod = importSpecModule imp_spec
1033 imp_msg = ptext (sLit "imported from") <+> ppr imp_mod <> extra
1034 extra | imp_mod == moduleName name_mod = empty
1035 | otherwise = ptext (sLit ", but defined in") <+> ppr name_mod
1037 check _ _ _ = return () -- Local, or not used, or not deprectated
1038 -- The Imported pattern-match: don't deprecate locally defined names
1039 -- For a start, we may be exporting a deprecated thing
1040 -- Also we may use a deprecated thing in the defn of another
1041 -- deprecated things. We may even use a deprecated thing in
1042 -- the defn of a non-deprecated thing, when changing a module's
1045 lookupImpDeprec :: DynFlags -> HomePackageTable -> PackageIfaceTable
1046 -> GlobalRdrElt -> Maybe WarningTxt
1047 -- The name is definitely imported, so look in HPT, PIT
1048 lookupImpDeprec dflags hpt pit gre
1049 = case lookupIfaceByModule dflags hpt pit mod of
1050 Just iface -> mi_warn_fn iface name `mplus` -- Bleat if the thing, *or
1052 ParentIs p -> mi_warn_fn iface p -- its parent*, is warn'd
1055 Nothing -> Nothing -- See Note [Used names with interface not loaded]
1058 mod = ASSERT2( isExternalName name, ppr name ) nameModule name
1061 Note [Used names with interface not loaded]
1062 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1063 By now all the interfaces should have been loaded,
1064 because reportDeprecations happens after typechecking.
1065 However, it's still (just) possible to to find a used
1066 Name whose interface hasn't been loaded:
1068 a) It might be a WiredInName; in that case we may not load
1069 its interface (although we could).
1071 b) It might be GHC.Real.fromRational, or GHC.Num.fromInteger
1072 These are seen as "used" by the renamer (if -XNoImplicitPrelude)
1073 is on), but the typechecker may discard their uses
1074 if in fact the in-scope fromRational is GHC.Read.fromRational,
1075 (see tcPat.tcOverloadedLit), and the typechecker sees that the type
1076 is fixed, say, to GHC.Base.Float (see Inst.lookupSimpleInst).
1077 In that obscure case it won't force the interface in.
1079 In both cases we simply don't permit deprecations;
1080 this is, after all, wired-in stuff.
1083 %*********************************************************
1087 %*********************************************************
1090 reportUnusedNames :: Maybe [LIE RdrName] -- Export list
1091 -> TcGblEnv -> RnM ()
1092 reportUnusedNames export_decls gbl_env
1093 = do { traceRn ((text "RUN") <+> (ppr (tcg_dus gbl_env)))
1094 ; warnUnusedTopBinds unused_locals
1095 ; warnUnusedModules unused_imp_mods
1096 ; warnUnusedImports unused_imports
1097 ; warnDuplicateImports defined_and_used
1098 ; printMinimalImports minimal_imports }
1100 used_names :: NameSet
1101 used_names = findUses (tcg_dus gbl_env) emptyNameSet
1102 -- NB: currently, if f x = g, we only treat 'g' as used if 'f' is used
1105 -- Collect the defined names from the in-scope environment
1106 defined_names :: [GlobalRdrElt]
1107 defined_names = globalRdrEnvElts (tcg_rdr_env gbl_env)
1109 -- Note that defined_and_used, defined_but_not_used
1110 -- are both [GRE]; that's why we need defined_and_used
1111 -- rather than just used_names
1112 defined_and_used, defined_but_not_used :: [GlobalRdrElt]
1113 (defined_and_used, defined_but_not_used)
1114 = partition (gre_is_used used_names) defined_names
1116 kids_env = mkChildEnv defined_names
1117 -- This is done in mkExports too; duplicated work
1119 gre_is_used :: NameSet -> GlobalRdrElt -> Bool
1120 gre_is_used used_names (GRE {gre_name = name})
1121 = name `elemNameSet` used_names
1122 || any (`elemNameSet` used_names) (findChildren kids_env name)
1123 -- A use of C implies a use of T,
1124 -- if C was brought into scope by T(..) or T(C)
1126 -- Filter out the ones that are
1127 -- (a) defined in this module, and
1128 -- (b) not defined by a 'deriving' clause
1129 -- The latter have an Internal Name, so we can filter them out easily
1130 unused_locals :: [GlobalRdrElt]
1131 unused_locals = filter is_unused_local defined_but_not_used
1132 is_unused_local :: GlobalRdrElt -> Bool
1133 is_unused_local gre = isLocalGRE gre && isExternalName (gre_name gre)
1135 unused_imports :: [GlobalRdrElt]
1136 unused_imports = mapCatMaybes unused_imp defined_but_not_used
1137 unused_imp :: GlobalRdrElt -> Maybe GlobalRdrElt -- Result has trimmed Imported provenances
1138 unused_imp (GRE {gre_prov = LocalDef}) = Nothing
1139 unused_imp gre@(GRE {gre_prov = Imported imp_specs})
1140 | null trimmed_specs = Nothing
1141 | otherwise = Just (gre {gre_prov = Imported trimmed_specs})
1143 trimmed_specs = filter report_if_unused imp_specs
1145 -- To figure out the minimal set of imports, start with the things
1146 -- that are in scope (i.e. in gbl_env). Then just combine them
1147 -- into a bunch of avails, so they are properly grouped
1149 -- BUG WARNING: this does not deal properly with qualified imports!
1150 minimal_imports :: FiniteMap ModuleName AvailEnv
1151 minimal_imports0 = foldr add_expall emptyFM expall_mods
1152 minimal_imports1 = foldr add_name minimal_imports0 defined_and_used
1153 minimal_imports = foldr add_inst_mod minimal_imports1 direct_import_mods
1154 -- The last line makes sure that we retain all direct imports
1155 -- even if we import nothing explicitly.
1156 -- It's not necessarily redundant to import such modules. Consider
1160 -- The import M() is not *necessarily* redundant, even if
1161 -- we suck in no instance decls from M (e.g. it contains
1162 -- no instance decls, or This contains no code). It may be
1163 -- that we import M solely to ensure that M's orphan instance
1164 -- decls (or those in its imports) are visible to people who
1165 -- import This. Sigh.
1166 -- There's really no good way to detect this, so the error message
1167 -- in RnEnv.warnUnusedModules is weakened instead
1169 -- We've carefully preserved the provenance so that we can
1170 -- construct minimal imports that import the name by (one of)
1171 -- the same route(s) as the programmer originally did.
1172 add_name gre@(GRE {gre_prov = Imported (imp_spec:_)}) acc
1173 = addToFM_C plusAvailEnv acc
1174 (importSpecModule imp_spec) (unitAvailEnv (greAvail gre))
1175 add_name _ acc = acc -- Local
1177 -- Modules mentioned as 'module M' in the export list
1178 expall_mods = case export_decls of
1180 Just es -> [m | L _ (IEModuleContents m) <- es]
1182 -- This is really bogus. The idea is that if we see 'module M' in
1183 -- the export list we must retain the import decls that drive it
1184 -- If we aren't careful we might see
1185 -- module A( module M ) where
1188 -- and suppose that N exports everything that M does. Then we
1189 -- must not drop the import of M even though N brings it all into
1192 -- BUG WARNING: 'module M' exports aside, what if M.x is mentioned?!
1194 -- The reason that add_expall is bogus is that it doesn't take
1195 -- qualified imports into account. But it's an improvement.
1196 add_expall mod acc = addToFM_C plusAvailEnv acc mod emptyAvailEnv
1198 add_inst_mod (mod, _) acc
1199 | mod_name `elemFM` acc = acc -- We import something already
1200 | otherwise = addToFM acc mod_name emptyAvailEnv
1202 mod_name = moduleName mod
1203 -- Add an empty collection of imports for a module
1204 -- from which we have sucked only instance decls
1206 imports = tcg_imports gbl_env
1208 direct_import_mods :: [(Module, [(ModuleName, Bool, SrcSpan)])]
1209 -- See the type of the imp_mods for this triple
1210 direct_import_mods = fmToList (imp_mods imports)
1212 -- unused_imp_mods are the directly-imported modules
1213 -- that are not mentioned in minimal_imports1
1214 -- [Note: not 'minimal_imports', because that includes directly-imported
1215 -- modules even if we use nothing from them; see notes above]
1217 -- BUG WARNING: this code is generally buggy
1218 unused_imp_mods :: [(ModuleName, SrcSpan)]
1219 unused_imp_mods = [(mod_name,loc)
1220 | (mod, xs) <- direct_import_mods,
1221 (_, no_imp, loc) <- xs,
1222 let mod_name = moduleName mod,
1223 not (mod_name `elemFM` minimal_imports1),
1224 moduleName mod /= pRELUDE_NAME,
1225 -- XXX not really correct, but we don't want
1226 -- to generate warnings when compiling against
1227 -- a compat version of base.
1229 -- The not no_imp part is not to complain about
1230 -- import M (), which is an idiom for importing
1231 -- instance declarations
1233 module_unused :: ModuleName -> Bool
1234 module_unused mod = any (((==) mod) . fst) unused_imp_mods
1236 report_if_unused :: ImportSpec -> Bool
1237 -- Do we want to report this as an unused import?
1238 report_if_unused (ImpSpec {is_decl = d, is_item = i})
1239 = not (module_unused (is_mod d)) -- Not if we've already said entire import is unused
1240 && isExplicitItem i -- Only if the import was explicit
1242 ---------------------
1243 warnDuplicateImports :: [GlobalRdrElt] -> RnM ()
1244 -- Given the GREs for names that are used, figure out which imports
1245 -- could be omitted without changing the top-level environment.
1247 -- NB: Given import Foo( T )
1248 -- import qualified Foo
1249 -- we do not report a duplicate import, even though Foo.T is brought
1250 -- into scope by both, because there's nothing you can *omit* without
1251 -- changing the top-level environment. So we complain only if it's
1252 -- explicitly named in both imports or neither.
1254 -- Furthermore, we complain about Foo.T only if
1255 -- there is no complaint about (unqualified) T
1257 warnDuplicateImports gres
1258 = ifOptM Opt_WarnUnusedImports $
1259 sequence_ [ warn name pr
1260 | GRE { gre_name = name, gre_prov = Imported imps } <- gres
1261 , pr <- redundants imps ]
1263 warn name (red_imp, cov_imp)
1264 = addWarnAt (importSpecLoc red_imp)
1265 (vcat [ptext (sLit "Redundant import of:") <+> quotes pp_name,
1266 ptext (sLit "It is also") <+> ppr cov_imp])
1268 pp_name | is_qual red_decl = ppr (is_as red_decl) <> dot <> ppr occ
1269 | otherwise = ppr occ
1270 occ = nameOccName name
1271 red_decl = is_decl red_imp
1273 redundants :: [ImportSpec] -> [(ImportSpec,ImportSpec)]
1274 -- The returned pair is (redundant-import, covering-import)
1276 = [ (red_imp, cov_imp)
1278 , isExplicitItem (is_item red_imp)
1279 -- Complain only about redundant imports
1280 -- mentioned explicitly by the user
1281 , cov_imp <- take 1 (filter (covers red_imp) imps) ]
1282 -- The 'take 1' picks the first offending group
1283 -- for this particular name
1285 -- "red_imp" is a putative redundant import
1286 -- "cov_imp" potentially covers it
1287 -- This test decides whether red_imp could be dropped
1289 -- NOTE: currently the test does not warn about
1292 -- even if the same underlying 'x' is involved, because dropping
1293 -- either import would change the qualified names in scope (M.x, N.x)
1294 -- But if the qualified names aren't used, the import is indeed redundant
1295 -- Sadly we don't know that. Oh well.
1296 covers red_imp@(ImpSpec { is_decl = red_decl })
1297 cov_imp@(ImpSpec { is_decl = cov_decl, is_item = cov_item })
1298 | red_loc == cov_loc
1299 = False -- Ignore diagonal elements
1300 | not (is_as red_decl == is_as cov_decl)
1301 = False -- They bring into scope different qualified names
1302 | not (is_qual red_decl) && is_qual cov_decl
1303 = False -- Covering one doesn't bring unqualified name into scope
1305 = not (isExplicitItem cov_item) -- Redundant one is selective and covering one isn't
1306 || red_later -- or both are explicit; tie-break using red_later
1309 = not cov_selective -- Redundant one is selective and covering one isn't
1310 || red_later -- Both are explicit; tie-break using red_later
1312 = not cov_selective -- Neither import is selective
1313 && (is_mod red_decl == is_mod cov_decl) -- They import the same module
1314 && red_later -- Tie-break
1317 red_loc = importSpecLoc red_imp
1318 cov_loc = importSpecLoc cov_imp
1319 red_later = red_loc > cov_loc
1321 -- ToDo: deal with original imports with 'qualified' and 'as M' clauses
1322 printMinimalImports :: FiniteMap ModuleName AvailEnv -- Minimal imports
1324 printMinimalImports imps
1325 = ifOptM Opt_D_dump_minimal_imports $ do {
1327 mod_ies <- initIfaceTcRn $ mapM to_ies (fmToList imps) ;
1328 this_mod <- getModule ;
1329 rdr_env <- getGlobalRdrEnv ;
1330 dflags <- getDOpts ;
1331 liftIO $ do h <- openFile (mkFilename this_mod) WriteMode
1332 printForUser h (mkPrintUnqualified dflags rdr_env)
1333 (vcat (map ppr_mod_ie mod_ies))
1336 mkFilename this_mod = moduleNameString (moduleName this_mod) ++ ".imports"
1337 ppr_mod_ie (mod_name, ies)
1338 | mod_name == moduleName pRELUDE
1340 | null ies -- Nothing except instances comes from here
1341 = ptext (sLit "import") <+> ppr mod_name <> ptext (sLit "() -- Instances only")
1343 = ptext (sLit "import") <+> ppr mod_name <>
1344 parens (fsep (punctuate comma (map ppr ies)))
1346 to_ies (mod, avail_env) = do ies <- mapM to_ie (availEnvElts avail_env)
1349 to_ie :: AvailInfo -> IfG (IE Name)
1350 -- The main trick here is that if we're importing all the constructors
1351 -- we want to say "T(..)", but if we're importing only a subset we want
1352 -- to say "T(A,B,C)". So we have to find out what the module exports.
1353 to_ie (Avail n) = return (IEVar n)
1354 to_ie (AvailTC n [m]) = ASSERT( n==m )
1355 return (IEThingAbs n)
1356 to_ie (AvailTC n ns) = do
1357 iface <- loadSysInterface doc n_mod
1358 case [xs | (m,as) <- mi_exports iface,
1361 x == nameOccName n] of
1362 [xs] | all_used xs -> return (IEThingAll n)
1363 | otherwise -> return (IEThingWith n (filter (/= n) ns))
1364 other -> pprTrace "to_ie" (ppr n <+> ppr n_mod <+> ppr other) $
1367 all_used avail_occs = all (`elem` map nameOccName ns) avail_occs
1368 doc = text "Compute minimal imports from" <+> ppr n
1369 n_mod = ASSERT( isExternalName n ) nameModule n
1373 %************************************************************************
1377 %************************************************************************
1380 badImportItemErr :: ModIface -> ImpDeclSpec -> IE RdrName -> SDoc
1381 badImportItemErr iface decl_spec ie
1382 = sep [ptext (sLit "Module"), quotes (ppr (is_mod decl_spec)), source_import,
1383 ptext (sLit "does not export"), quotes (ppr ie)]
1385 source_import | mi_boot iface = ptext (sLit "(hi-boot interface)")
1388 illegalImportItemErr :: SDoc
1389 illegalImportItemErr = ptext (sLit "Illegal import item")
1391 dodgyImportWarn :: RdrName -> SDoc
1392 dodgyImportWarn item = dodgyMsg (ptext (sLit "import")) item
1393 dodgyExportWarn :: Name -> SDoc
1394 dodgyExportWarn item = dodgyMsg (ptext (sLit "export")) item
1396 dodgyMsg :: OutputableBndr n => SDoc -> n -> SDoc
1398 = sep [ ptext (sLit "The") <+> kind <+> ptext (sLit "item") <+> quotes (ppr (IEThingAll tc))
1399 <+> ptext (sLit "suggests that"),
1400 quotes (ppr tc) <+> ptext (sLit "has (in-scope) constructors or class methods,"),
1401 ptext (sLit "but it has none") ]
1403 exportItemErr :: IE RdrName -> SDoc
1404 exportItemErr export_item
1405 = sep [ ptext (sLit "The export item") <+> quotes (ppr export_item),
1406 ptext (sLit "attempts to export constructors or class methods that are not visible here") ]
1408 typeItemErr :: Name -> SDoc -> SDoc
1409 typeItemErr name wherestr
1410 = sep [ ptext (sLit "Using 'type' tag on") <+> quotes (ppr name) <+> wherestr,
1411 ptext (sLit "Use -XTypeFamilies to enable this extension") ]
1413 exportClashErr :: GlobalRdrEnv -> Name -> Name -> IE RdrName -> IE RdrName
1415 exportClashErr global_env name1 name2 ie1 ie2
1416 = vcat [ ptext (sLit "Conflicting exports for") <+> quotes (ppr occ) <> colon
1417 , ppr_export ie1' name1'
1418 , ppr_export ie2' name2' ]
1420 occ = nameOccName name1
1421 ppr_export ie name = nest 2 (quotes (ppr ie) <+> ptext (sLit "exports") <+>
1422 quotes (ppr name) <+> pprNameProvenance (get_gre name))
1424 -- get_gre finds a GRE for the Name, so that we can show its provenance
1426 = case lookupGRE_Name global_env name of
1428 [] -> pprPanic "exportClashErr" (ppr name)
1429 get_loc name = nameSrcLoc $ gre_name $ get_gre name
1430 (name1', ie1', name2', ie2') = if get_loc name1 < get_loc name2
1431 then (name1, ie1, name2, ie2)
1432 else (name2, ie2, name1, ie1)
1434 addDupDeclErr :: [Name] -> TcRn ()
1436 = panic "addDupDeclErr: empty list"
1437 addDupDeclErr names@(name : _)
1438 = addErrAt (getSrcSpan (last sorted_names)) $
1439 -- Report the error at the later location
1440 vcat [ptext (sLit "Multiple declarations of") <+> quotes (ppr name),
1441 ptext (sLit "Declared at:") <+> vcat (map (ppr . nameSrcLoc) sorted_names)]
1443 sorted_names = sortWith nameSrcLoc names
1445 dupExportWarn :: OccName -> IE RdrName -> IE RdrName -> SDoc
1446 dupExportWarn occ_name ie1 ie2
1447 = hsep [quotes (ppr occ_name),
1448 ptext (sLit "is exported by"), quotes (ppr ie1),
1449 ptext (sLit "and"), quotes (ppr ie2)]
1451 dupModuleExport :: ModuleName -> SDoc
1453 = hsep [ptext (sLit "Duplicate"),
1454 quotes (ptext (sLit "Module") <+> ppr mod),
1455 ptext (sLit "in export list")]
1457 moduleNotImported :: ModuleName -> SDoc
1458 moduleNotImported mod
1459 = ptext (sLit "The export item `module") <+> ppr mod <>
1460 ptext (sLit "' is not imported")
1462 nullModuleExport :: ModuleName -> SDoc
1463 nullModuleExport mod
1464 = ptext (sLit "The export item `module") <+> ppr mod <> ptext (sLit "' exports nothing")
1466 moduleWarn :: ModuleName -> WarningTxt -> SDoc
1467 moduleWarn mod (WarningTxt txt)
1468 = sep [ ptext (sLit "Module") <+> quotes (ppr mod) <> ptext (sLit ":"),
1470 moduleWarn mod (DeprecatedTxt txt)
1471 = sep [ ptext (sLit "Module") <+> quotes (ppr mod)
1472 <+> ptext (sLit "is deprecated:"),
1475 implicitPreludeWarn :: SDoc
1477 = ptext (sLit "Module `Prelude' implicitly imported")
1479 packageImportErr :: SDoc
1481 = ptext (sLit "Package-qualified imports are not enabled; use -XPackageImports")