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)
24 import HeaderInfo ( mkPrelImports )
40 import Data.List ( partition, (\\), delete )
41 import qualified Data.Set as Set
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 (moduleName 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 rnImportDecl :: Module
89 -> LImportDecl RdrName
90 -> RnM (LImportDecl Name, GlobalRdrEnv, ImportAvails,AnyHpcUsage)
92 rnImportDecl this_mod (L loc (ImportDecl loc_imp_mod_name mb_pkg want_boot
93 qual_only as_mod imp_details))
96 when (isJust mb_pkg) $ do
97 pkg_imports <- doptM Opt_PackageImports
98 when (not pkg_imports) $ addErr packageImportErr
100 -- If there's an error in loadInterface, (e.g. interface
101 -- file not found) we get lots of spurious errors from 'filterImports'
103 imp_mod_name = unLoc loc_imp_mod_name
104 doc = ppr imp_mod_name <+> ptext (sLit "is directly imported")
106 iface <- loadSrcInterface doc imp_mod_name want_boot mb_pkg
108 -- Compiler sanity check: if the import didn't say
109 -- {-# SOURCE #-} we should not get a hi-boot file
110 WARN( not want_boot && mi_boot iface, ppr imp_mod_name ) (do
112 -- Issue a user warning for a redundant {- SOURCE -} import
113 -- NB that we arrange to read all the ordinary imports before
114 -- any of the {- SOURCE -} imports.
116 -- in --make and GHCi, the compilation manager checks for this,
117 -- and indeed we shouldn't do it here because the existence of
118 -- the non-boot module depends on the compilation order, which
119 -- is not deterministic. The hs-boot test can show this up.
121 warnIf (want_boot && not (mi_boot iface) && isOneShot (ghcMode dflags))
122 (warnRedundantSourceImport imp_mod_name)
125 imp_mod = mi_module iface
126 warns = mi_warns iface
127 orph_iface = mi_orphan iface
128 has_finsts = mi_finsts iface
131 filtered_exports = filter not_this_mod (mi_exports iface)
132 not_this_mod (mod,_) = mod /= this_mod
133 -- If the module exports anything defined in this module, just
134 -- ignore it. Reason: otherwise it looks as if there are two
135 -- local definition sites for the thing, and an error gets
136 -- reported. Easiest thing is just to filter them out up
137 -- front. This situation only arises if a module imports
138 -- itself, or another module that imported it. (Necessarily,
139 -- this invoves a loop.)
141 -- Tiresome consequence: if you say
146 -- module B( AType ) where
147 -- import {-# SOURCE #-} A( AType )
149 -- then you'll get a 'B does not export AType' message. Oh well.
151 qual_mod_name = case as_mod of
152 Nothing -> imp_mod_name
153 Just another_name -> another_name
154 imp_spec = ImpDeclSpec { is_mod = imp_mod_name, is_qual = qual_only,
155 is_dloc = loc, is_as = qual_mod_name }
158 -- Get the total exports from this module
159 total_avails <- ifaceExportNames filtered_exports
161 -- filter the imports according to the import declaration
162 (new_imp_details, gbl_env) <-
163 filterImports iface imp_spec imp_details total_avails
168 -- Compute new transitive dependencies
170 orphans | orph_iface = ASSERT( not (imp_mod `elem` dep_orphs deps) )
171 imp_mod : dep_orphs deps
172 | otherwise = dep_orphs deps
174 finsts | has_finsts = ASSERT( not (imp_mod `elem` dep_finsts deps) )
175 imp_mod : dep_finsts deps
176 | otherwise = dep_finsts deps
178 pkg = modulePackageId (mi_module iface)
180 (dependent_mods, dependent_pkgs)
181 | pkg == thisPackage dflags =
182 -- Imported module is from the home package
183 -- Take its dependent modules and add imp_mod itself
184 -- Take its dependent packages unchanged
186 -- NB: (dep_mods deps) might include a hi-boot file
187 -- for the module being compiled, CM. Do *not* filter
188 -- this out (as we used to), because when we've
189 -- finished dealing with the direct imports we want to
190 -- know if any of them depended on CM.hi-boot, in
191 -- which case we should do the hi-boot consistency
192 -- check. See LoadIface.loadHiBootInterface
193 ((imp_mod_name, want_boot) : dep_mods deps, dep_pkgs deps)
196 -- Imported module is from another package
197 -- Dump the dependent modules
198 -- Add the package imp_mod comes from to the dependent packages
199 ASSERT2( not (pkg `elem` dep_pkgs deps), ppr pkg <+> ppr (dep_pkgs deps) )
200 ([], pkg : dep_pkgs deps)
202 -- True <=> import M ()
203 import_all = case imp_details of
204 Just (is_hiding, ls) -> not is_hiding && null ls
207 imports = ImportAvails {
208 imp_mods = unitModuleEnv imp_mod [(qual_mod_name, import_all, loc)],
211 imp_dep_mods = mkModDeps dependent_mods,
212 imp_dep_pkgs = dependent_pkgs
215 -- Complain if we import a deprecated module
216 ifOptM Opt_WarnWarningsDeprecations (
218 WarnAll txt -> addWarn (moduleWarn imp_mod_name txt)
222 let new_imp_decl = L loc (ImportDecl loc_imp_mod_name mb_pkg want_boot
223 qual_only as_mod new_imp_details)
225 return (new_imp_decl, gbl_env, imports, mi_hpc iface)
228 warnRedundantSourceImport :: ModuleName -> SDoc
229 warnRedundantSourceImport mod_name
230 = ptext (sLit "Unnecessary {-# SOURCE #-} in the import of module")
231 <+> quotes (ppr mod_name)
235 %************************************************************************
237 importsFromLocalDecls
239 %************************************************************************
241 From the top-level declarations of this module produce
242 * the lexical environment
244 created by its bindings.
246 Note [Top-level Names in Template Haskell decl quotes]
247 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
248 Consider a Template Haskell declaration quotation like this:
251 When renaming the declarations inside [d| ...|], we treat the
252 top level binders specially in two ways
254 1. We give them an Internal name, not (as usual) an External one.
255 Otherwise the NameCache gets confused by a second allocation of
256 M.f. (We used to invent a fake module ThFake to avoid this, but
257 that had other problems, notably in getting the correct answer for
258 nameIsLocalOrFrom in lookupFixity. So we now leave tcg_module
261 2. We make them *shadow* the outer bindings. If we don't do that,
262 we'll get a complaint when extending the GlobalRdrEnv, saying that
263 there are two bindings for 'f'.
265 This shadowing applies even if the binding for 'f' is in a
266 where-clause, and hence is in the *local* RdrEnv not the *global*
269 We find out whether we are inside a [d| ... |] by testing the TH
270 stage. This is a slight hack, because the stage field was really meant for
271 the type checker, and here we are not interested in the fields of Brack,
272 hence the error thunks in thRnBrack.
275 extendGlobalRdrEnvRn :: [AvailInfo]
277 -> RnM (TcGblEnv, TcLclEnv)
278 -- Updates both the GlobalRdrEnv and the FixityEnv
279 -- We return a new TcLclEnv only becuase we might have to
280 -- delete some bindings from it;
281 -- see Note [Top-level Names in Template Haskell decl quotes]
283 extendGlobalRdrEnvRn avails new_fixities
284 = do { (gbl_env, lcl_env) <- getEnvs
286 ; let rdr_env = tcg_rdr_env gbl_env
287 fix_env = tcg_fix_env gbl_env
289 -- Delete new_occs from global and local envs
290 -- If we are in a TemplateHaskell decl bracket,
291 -- we are going to shadow them
292 -- See Note [Top-level Names in Template Haskell decl quotes]
293 shadowP = isBrackStage stage
294 new_occs = map (nameOccName . gre_name) gres
295 rdr_env1 = hideSomeUnquals rdr_env new_occs
296 lcl_env1 = lcl_env { tcl_rdr = delListFromOccEnv (tcl_rdr lcl_env) new_occs }
297 (rdr_env2, lcl_env2) | shadowP = (rdr_env1, lcl_env1)
298 | otherwise = (rdr_env, lcl_env)
300 rdr_env3 = foldl extendGlobalRdrEnv rdr_env2 gres
301 fix_env' = foldl extend_fix_env fix_env gres
302 (rdr_env', dups) = findLocalDupsRdrEnv rdr_env3 new_occs
304 gbl_env' = gbl_env { tcg_rdr_env = rdr_env', tcg_fix_env = fix_env' }
306 ; mapM_ addDupDeclErr dups
308 ; traceRn (text "extendGlobalRdrEnvRn" <+> (ppr new_fixities $$ ppr fix_env $$ ppr fix_env'))
309 ; return (gbl_env', lcl_env2) }
311 gres = gresFromAvails LocalDef avails
313 -- If there is a fixity decl for the gre, add it to the fixity env
314 extend_fix_env fix_env gre
315 | Just (L _ fi) <- lookupFsEnv new_fixities (occNameFS occ)
316 = extendNameEnv fix_env name (FixItem occ fi)
321 occ = nameOccName name
324 @getLocalDeclBinders@ returns the names for an @HsDecl@. It's
325 used for source code.
327 *** See "THE NAMING STORY" in HsDecls ****
329 Instances of type families
330 ~~~~~~~~~~~~~~~~~~~~~~~~~~
331 Family instances contain data constructors that we need to collect and we also
332 need to descend into the type instances of associated families in class
333 instances. The type constructor of a family instance is a usage occurence.
334 Hence, we don't return it as a subname in 'AvailInfo'; otherwise, we would get
335 a duplicate declaration error.
337 Note [Looking up family names in family instances]
338 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
343 type instance M.T Int = Bool
345 We might think that we can simply use 'lookupOccRn' when processing the type
346 instance to look up 'M.T'. Alas, we can't! The type family declaration is in
347 the *same* HsGroup as the type instance declaration. Hence, as we are
348 currently collecting the binders declared in that HsGroup, these binders will
349 not have been added to the global environment yet.
351 In the case of type classes, this problem does not arise, as a class instance
352 does not define any binders of it's own. So, we simply don't attempt to look
353 up the class names of class instances in 'get_local_binders' below.
355 If we don't look up class instances, can't we get away without looking up type
356 instances, too? No, we can't. Data type instances define data constructors
359 (1) collect those in 'get_local_binders' and
360 (2) we need to get their parent name in 'get_local_binders', too, to
361 produce an appropriate 'AvailTC'.
363 This parent name is exactly the family name of the type instance that is so
364 difficult to look up.
366 We solve this problem as follows:
368 (a) We process all type declarations other than type instances first.
369 (b) Then, we compute a 'GlobalRdrEnv' from the result of the first step.
370 (c) Finally, we process all type instances (both those on the toplevel and
371 those nested in class instances) and check for the family names in the
372 'GlobalRdrEnv' produced in the previous step before using 'lookupOccRn'.
375 getLocalNonValBinders :: HsGroup RdrName -> RnM [AvailInfo]
376 -- Get all the top-level binders bound the group *except*
377 -- for value bindings, which are treated separately
378 -- Specificaly we return AvailInfo for
383 -- (in hs-boot files) value signatures
385 getLocalNonValBinders group
386 = do { gbl_env <- getGblEnv
387 ; get_local_binders gbl_env group }
389 get_local_binders :: TcGblEnv -> HsGroup RdrName -> RnM [GenAvailInfo Name]
390 get_local_binders gbl_env (HsGroup {hs_valds = ValBindsIn _ val_sigs,
391 hs_tyclds = tycl_decls,
392 hs_instds = inst_decls,
393 hs_fords = foreign_decls })
394 = do { -- separate out the family instance declarations
395 let (tyinst_decls1, tycl_decls_noinsts)
396 = partition (isFamInstDecl . unLoc) tycl_decls
397 tyinst_decls = tyinst_decls1 ++ instDeclATs inst_decls
399 -- process all type/class decls except family instances
400 ; tc_names <- mapM new_tc tycl_decls_noinsts
402 -- create a temporary rdr env of the type binders
403 ; let tc_gres = gresFromAvails LocalDef tc_names
404 tc_name_env = foldl extendGlobalRdrEnv emptyGlobalRdrEnv tc_gres
406 -- process all family instances
407 ; ti_names <- mapM (new_ti tc_name_env) tyinst_decls
409 -- finish off with value binder in case of a hs-boot file
410 ; val_names <- mapM new_simple val_bndrs
411 ; return (val_names ++ tc_names ++ ti_names) }
413 is_hs_boot = isHsBoot (tcg_src gbl_env) ;
415 for_hs_bndrs :: [Located RdrName]
416 for_hs_bndrs = [nm | L _ (ForeignImport nm _ _) <- foreign_decls]
418 -- In a hs-boot file, the value binders come from the
419 -- *signatures*, and there should be no foreign binders
420 val_bndrs :: [Located RdrName]
421 val_bndrs | is_hs_boot = [nm | L _ (TypeSig nm _) <- val_sigs]
422 | otherwise = for_hs_bndrs
424 new_simple :: Located RdrName -> RnM (GenAvailInfo Name)
425 new_simple rdr_name = do
426 nm <- newTopSrcBinder rdr_name
429 new_tc tc_decl -- NOT for type/data instances
430 = do { main_name <- newTopSrcBinder main_rdr
431 ; sub_names <- mapM newTopSrcBinder sub_rdrs
432 ; return (AvailTC main_name (main_name : sub_names)) }
434 (main_rdr : sub_rdrs) = hsTyClDeclBinders tc_decl
436 new_ti tc_name_env ti_decl -- ONLY for type/data instances
437 = do { main_name <- lookupFamInstDeclBndr tc_name_env main_rdr
438 ; sub_names <- mapM newTopSrcBinder sub_rdrs
439 ; return (AvailTC main_name sub_names) }
440 -- main_name is not bound here!
442 (main_rdr : sub_rdrs) = hsTyClDeclBinders ti_decl
444 get_local_binders _ g = pprPanic "get_local_binders" (ppr g)
448 %************************************************************************
450 \subsection{Filtering imports}
452 %************************************************************************
454 @filterImports@ takes the @ExportEnv@ telling what the imported module makes
455 available, and filters it through the import spec (if any).
458 filterImports :: ModIface
459 -> ImpDeclSpec -- The span for the entire import decl
460 -> Maybe (Bool, [LIE RdrName]) -- Import spec; True => hiding
461 -> [AvailInfo] -- What's available
462 -> RnM (Maybe (Bool, [LIE Name]), -- Import spec w/ Names
463 GlobalRdrEnv) -- Same again, but in GRE form
464 filterImports _ decl_spec Nothing all_avails
465 = return (Nothing, mkGlobalRdrEnv (gresFromAvails prov all_avails))
467 prov = Imported [ImpSpec { is_decl = decl_spec, is_item = ImpAll }]
470 filterImports iface decl_spec (Just (want_hiding, import_items)) all_avails
471 = do -- check for errors, convert RdrNames to Names
472 opt_typeFamilies <- doptM Opt_TypeFamilies
473 items1 <- mapM (lookup_lie opt_typeFamilies) import_items
475 let items2 :: [(LIE Name, AvailInfo)]
476 items2 = concat items1
477 -- NB the AvailInfo may have duplicates, and several items
478 -- for the same parent; e.g N(x) and N(y)
480 names = availsToNameSet (map snd items2)
481 keep n = not (n `elemNameSet` names)
482 pruned_avails = filterAvails keep all_avails
483 hiding_prov = Imported [ImpSpec { is_decl = decl_spec, is_item = ImpAll }]
485 gres | want_hiding = gresFromAvails hiding_prov pruned_avails
486 | otherwise = concatMap (gresFromIE decl_spec) items2
488 return (Just (want_hiding, map fst items2), mkGlobalRdrEnv gres)
490 -- This environment is how we map names mentioned in the import
491 -- list to the actual Name they correspond to, and the name family
492 -- that the Name belongs to (the AvailInfo). The situation is
493 -- complicated by associated families, which introduce a three-level
494 -- hierachy, where class = grand parent, assoc family = parent, and
495 -- data constructors = children. The occ_env entries for associated
496 -- families needs to capture all this information; hence, we have the
497 -- third component of the environment that gives the class name (=
498 -- grand parent) in case of associated families.
500 -- This env will have entries for data constructors too,
501 -- they won't make any difference because naked entities like T
502 -- in an import list map to TcOccs, not VarOccs.
503 occ_env :: OccEnv (Name, -- the name
504 AvailInfo, -- the export item providing the name
505 Maybe Name) -- the parent of associated types
506 occ_env = mkOccEnv_C combine [ (nameOccName n, (n, a, Nothing))
507 | a <- all_avails, n <- availNames a]
509 -- we know that (1) there are at most entries for one name, (2) their
510 -- first component is identical, (3) they are for tys/cls, and (4) one
511 -- entry has the name in its parent position (the other doesn't)
512 combine (name, AvailTC p1 subs1, Nothing)
513 (_ , AvailTC p2 subs2, Nothing)
515 (parent, subs) = if p1 == name then (p2, subs1) else (p1, subs2)
517 (name, AvailTC name subs, Just parent)
518 combine x y = pprPanic "filterImports/combine" (ppr x $$ ppr y)
520 lookup_lie :: Bool -> LIE RdrName -> TcRn [(LIE Name, AvailInfo)]
521 lookup_lie opt_typeFamilies (L loc ieRdr)
523 stuff <- setSrcSpan loc $
524 case lookup_ie opt_typeFamilies ieRdr of
525 Failed err -> addErr err >> return []
526 Succeeded a -> return a
527 checkDodgyImport stuff
528 return [ (L loc ie, avail) | (ie,avail) <- stuff ]
530 -- Warn when importing T(..) if T was exported abstractly
531 checkDodgyImport stuff
532 | IEThingAll n <- ieRdr, (_, AvailTC _ [_]):_ <- stuff
533 = ifOptM Opt_WarnDodgyImports (addWarn (dodgyImportWarn n))
534 -- NB. use the RdrName for reporting the warning
538 -- For each import item, we convert its RdrNames to Names,
539 -- and at the same time construct an AvailInfo corresponding
540 -- to what is actually imported by this item.
541 -- Returns Nothing on error.
542 -- We return a list here, because in the case of an import
543 -- item like C, if we are hiding, then C refers to *both* a
544 -- type/class and a data constructor. Moreover, when we import
545 -- data constructors of an associated family, we need separate
546 -- AvailInfos for the data constructors and the family (as they have
547 -- different parents). See the discussion at occ_env.
548 lookup_ie :: Bool -> IE RdrName -> MaybeErr Message [(IE Name,AvailInfo)]
549 lookup_ie opt_typeFamilies ie
550 = let bad_ie = Failed (badImportItemErr iface decl_spec ie)
553 | isQual rdr = Failed (qualImportItemErr rdr)
554 | Just nm <- lookupOccEnv occ_env (rdrNameOcc rdr) = return nm
559 (name, avail, _) <- lookup_name n
560 return [(IEVar name, trimAvail avail name)]
563 (name, avail@(AvailTC name2 subs), mb_parent) <- lookup_name tc
565 -- non-associated ty/cls
566 Nothing -> return [(IEThingAll name, avail)]
568 Just parent -> return [(IEThingAll name,
569 AvailTC name2 (subs \\ [name])),
570 (IEThingAll name, AvailTC parent [name])]
573 | want_hiding -- hiding ( C )
574 -- Here the 'C' can be a data constructor
575 -- *or* a type/class, or even both
576 -> let tc_name = lookup_name tc
577 dc_name = lookup_name (setRdrNameSpace tc srcDataName)
579 case catMaybeErr [ tc_name, dc_name ] of
581 names -> return [mkIEThingAbs name | name <- names]
583 -> do nameAvail <- lookup_name tc
584 return [mkIEThingAbs nameAvail]
586 IEThingWith tc ns -> do
587 (name, AvailTC _ subnames, mb_parent) <- lookup_name tc
589 env = mkOccEnv [(nameOccName s, s) | s <- subnames]
590 mb_children = map (lookupOccEnv env . rdrNameOcc) ns
591 children <- if any isNothing mb_children
593 else return (catMaybes mb_children)
594 -- check for proper import of type families
595 when (not opt_typeFamilies && any isTyConName children) $
596 Failed (typeItemErr (head . filter isTyConName $ children)
597 (text "in import list"))
599 -- non-associated ty/cls
600 Nothing -> return [(IEThingWith name children,
601 AvailTC name (name:children))]
603 Just parent -> return [(IEThingWith name children,
604 AvailTC name children),
605 (IEThingWith name children,
606 AvailTC parent [name])]
608 _other -> Failed illegalImportItemErr
609 -- could be IEModuleContents, IEGroup, IEDoc, IEDocNamed
613 mkIEThingAbs (n, av, Nothing ) = (IEThingAbs n, trimAvail av n)
614 mkIEThingAbs (n, _, Just parent) = (IEThingAbs n, AvailTC parent [n])
617 catMaybeErr :: [MaybeErr err a] -> [a]
618 catMaybeErr ms = [ a | Succeeded a <- ms ]
621 %************************************************************************
625 %************************************************************************
628 -- | make a 'GlobalRdrEnv' where all the elements point to the same
629 -- import declaration (useful for "hiding" imports, or imports with
631 gresFromAvails :: Provenance -> [AvailInfo] -> [GlobalRdrElt]
632 gresFromAvails prov avails
633 = concatMap (gresFromAvail (const prov)) avails
635 gresFromAvail :: (Name -> Provenance) -> AvailInfo -> [GlobalRdrElt]
636 gresFromAvail prov_fn avail
637 = [ GRE {gre_name = n,
638 gre_par = availParent n avail,
639 gre_prov = prov_fn n}
640 | n <- availNames avail ]
642 greAvail :: GlobalRdrElt -> AvailInfo
643 greAvail gre = mkUnitAvail (gre_name gre) (gre_par gre)
645 mkUnitAvail :: Name -> Parent -> AvailInfo
646 mkUnitAvail me (ParentIs p) = AvailTC p [me]
647 mkUnitAvail me NoParent | isTyConName me = AvailTC me [me]
648 | otherwise = Avail me
650 plusAvail :: GenAvailInfo Name -> GenAvailInfo Name -> GenAvailInfo Name
651 plusAvail (Avail n1) (Avail _) = Avail n1
652 plusAvail (AvailTC _ ns1) (AvailTC n2 ns2) = AvailTC n2 (ns1 `unionLists` ns2)
653 plusAvail a1 a2 = pprPanic "RnEnv.plusAvail" (hsep [ppr a1,ppr a2])
655 availParent :: Name -> AvailInfo -> Parent
656 availParent _ (Avail _) = NoParent
657 availParent n (AvailTC m _) | n == m = NoParent
658 | otherwise = ParentIs m
660 trimAvail :: AvailInfo -> Name -> AvailInfo
661 trimAvail (Avail n) _ = Avail n
662 trimAvail (AvailTC n ns) m = ASSERT( m `elem` ns) AvailTC n [m]
664 -- | filters 'AvailInfo's by the given predicate
665 filterAvails :: (Name -> Bool) -> [AvailInfo] -> [AvailInfo]
666 filterAvails keep avails = foldr (filterAvail keep) [] avails
668 -- | filters an 'AvailInfo' by the given predicate
669 filterAvail :: (Name -> Bool) -> AvailInfo -> [AvailInfo] -> [AvailInfo]
670 filterAvail keep ie rest =
672 Avail n | keep n -> ie : rest
675 let left = filter keep ns in
676 if null left then rest else AvailTC tc left : rest
678 -- | Given an import\/export spec, construct the appropriate 'GlobalRdrElt's.
679 gresFromIE :: ImpDeclSpec -> (LIE Name, AvailInfo) -> [GlobalRdrElt]
680 gresFromIE decl_spec (L loc ie, avail)
681 = gresFromAvail prov_fn avail
683 is_explicit = case ie of
684 IEThingAll name -> \n -> n == name
686 prov_fn name = Imported [imp_spec]
688 imp_spec = ImpSpec { is_decl = decl_spec, is_item = item_spec }
689 item_spec = ImpSome { is_explicit = is_explicit name, is_iloc = loc }
691 mkChildEnv :: [GlobalRdrElt] -> NameEnv [Name]
692 mkChildEnv gres = foldr add emptyNameEnv gres
694 add (GRE { gre_name = n, gre_par = ParentIs p }) env = extendNameEnv_Acc (:) singleton env p n
697 findChildren :: NameEnv [Name] -> Name -> [Name]
698 findChildren env n = lookupNameEnv env n `orElse` []
701 ---------------------------------------
704 All this AvailEnv stuff is hardly used; only in a very small
705 part of RnNames. Todo: remove?
706 ---------------------------------------
709 type AvailEnv = NameEnv AvailInfo -- Maps a Name to the AvailInfo that contains it
711 emptyAvailEnv :: AvailEnv
712 emptyAvailEnv = emptyNameEnv
715 unitAvailEnv :: AvailInfo -> AvailEnv
716 unitAvailEnv a = unitNameEnv (availName a) a
718 plusAvailEnv :: AvailEnv -> AvailEnv -> AvailEnv
719 plusAvailEnv = plusNameEnv_C plusAvail
721 availEnvElts :: AvailEnv -> [AvailInfo]
722 availEnvElts = nameEnvElts
725 addAvail :: AvailEnv -> AvailInfo -> AvailEnv
726 addAvail avails avail = extendNameEnv_C plusAvail avails (availName avail) avail
728 mkAvailEnv :: [AvailInfo] -> AvailEnv
729 -- 'avails' may have several items with the same availName
730 -- E.g import Ix( Ix(..), index )
731 -- will give Ix(Ix,index,range) and Ix(index)
732 -- We want to combine these; addAvail does that
733 mkAvailEnv avails = foldl addAvail emptyAvailEnv avails
735 -- After combining the avails, we need to ensure that the parent name is the
736 -- first entry in the list of subnames, if it is included at all. (Subsequent
737 -- functions rely on that.)
738 normaliseAvail :: AvailInfo -> AvailInfo
739 normaliseAvail avail@(Avail _) = avail
740 normaliseAvail (AvailTC name subs) = AvailTC name subs'
742 subs' = if name `elem` subs then name : (delete name subs) else subs
744 -- | combines 'AvailInfo's from the same family
745 nubAvails :: [AvailInfo] -> [AvailInfo]
746 nubAvails avails = map normaliseAvail . nameEnvElts . mkAvailEnv $ avails
750 %************************************************************************
752 \subsection{Export list processing}
754 %************************************************************************
756 Processing the export list.
758 You might think that we should record things that appear in the export
759 list as ``occurrences'' (using @addOccurrenceName@), but you'd be
760 wrong. We do check (here) that they are in scope, but there is no
761 need to slurp in their actual declaration (which is what
762 @addOccurrenceName@ forces).
764 Indeed, doing so would big trouble when compiling @PrelBase@, because
765 it re-exports @GHC@, which includes @takeMVar#@, whose type includes
766 @ConcBase.StateAndSynchVar#@, and so on...
769 type ExportAccum -- The type of the accumulating parameter of
770 -- the main worker function in rnExports
771 = ([LIE Name], -- Export items with Names
772 ExportOccMap, -- Tracks exported occurrence names
773 [AvailInfo]) -- The accumulated exported stuff
776 emptyExportAccum :: ExportAccum
777 emptyExportAccum = ([], emptyOccEnv, [])
779 type ExportOccMap = OccEnv (Name, IE RdrName)
780 -- Tracks what a particular exported OccName
781 -- in an export list refers to, and which item
782 -- it came from. It's illegal to export two distinct things
783 -- that have the same occurrence name
785 rnExports :: Bool -- False => no 'module M(..) where' header at all
786 -> Maybe [LIE RdrName] -- Nothing => no explicit export list
790 -- Complains if two distinct exports have same OccName
791 -- Warns about identical exports.
792 -- Complains about exports items not in scope
794 rnExports explicit_mod exports
795 tcg_env@(TcGblEnv { tcg_mod = this_mod,
796 tcg_rdr_env = rdr_env,
797 tcg_imports = imports })
799 -- If the module header is omitted altogether, then behave
800 -- as if the user had written "module Main(main) where..."
801 -- EXCEPT in interactive mode, when we behave as if he had
802 -- written "module Main where ..."
803 -- Reason: don't want to complain about 'main' not in scope
804 -- in interactive mode
807 | explicit_mod = exports
808 | ghcLink dflags == LinkInMemory = Nothing
809 | otherwise = Just ([noLoc (IEVar main_RDR_Unqual)])
810 -- ToDo: the 'noLoc' here is unhelpful if 'main'
811 -- turns out to be out of scope
813 ; (rn_exports, avails) <- exports_from_avail real_exports rdr_env imports this_mod
814 ; let final_avails = nubAvails avails -- Combine families
816 ; return (tcg_env { tcg_exports = final_avails,
817 tcg_rn_exports = case tcg_rn_exports tcg_env of
819 Just _ -> rn_exports,
820 tcg_dus = tcg_dus tcg_env `plusDU`
821 usesOnly (availsToNameSet final_avails) }) }
823 exports_from_avail :: Maybe [LIE RdrName]
824 -- Nothing => no explicit export list
828 -> RnM (Maybe [LIE Name], [AvailInfo])
830 exports_from_avail Nothing rdr_env _imports _this_mod
831 = -- The same as (module M) where M is the current module name,
832 -- so that's how we handle it.
834 avails = [ greAvail gre | gre <- globalRdrEnvElts rdr_env,
837 return (Nothing, avails)
839 exports_from_avail (Just rdr_items) rdr_env imports this_mod
840 = do (ie_names, _, exports) <- foldlM do_litem emptyExportAccum rdr_items
842 return (Just ie_names, exports)
844 do_litem :: ExportAccum -> LIE RdrName -> RnM ExportAccum
845 do_litem acc lie = setSrcSpan (getLoc lie) (exports_from_item acc lie)
847 kids_env :: NameEnv [Name] -- Maps a parent to its in-scope children
848 kids_env = mkChildEnv (globalRdrEnvElts rdr_env)
850 imported_modules = [ qual_name
851 | xs <- moduleEnvElts $ imp_mods imports,
852 (qual_name, _, _) <- xs ]
854 exports_from_item :: ExportAccum -> LIE RdrName -> RnM ExportAccum
855 exports_from_item acc@(ie_names, occs, exports)
856 (L loc ie@(IEModuleContents mod))
857 | let earlier_mods = [ mod | (L _ (IEModuleContents mod)) <- ie_names ]
858 , mod `elem` earlier_mods -- Duplicate export of M
859 = do { warn_dup_exports <- doptM Opt_WarnDuplicateExports ;
860 warnIf warn_dup_exports (dupModuleExport mod) ;
864 = do { implicit_prelude <- doptM Opt_ImplicitPrelude
865 ; warnDodgyExports <- doptM Opt_WarnDodgyExports
866 ; let { exportValid = (mod `elem` imported_modules)
867 || (moduleName this_mod == mod)
868 ; gres = filter (isModuleExported implicit_prelude mod)
869 (globalRdrEnvElts rdr_env)
870 ; names = map gre_name gres
873 ; checkErr exportValid (moduleNotImported mod)
874 ; warnIf (warnDodgyExports && exportValid && null gres) (nullModuleExport mod)
876 ; addUsedRdrNames (concat [ [mkRdrQual mod occ, mkRdrUnqual occ]
877 | occ <- map nameOccName names ])
878 -- The qualified and unqualified version of all of
879 -- these names are, in effect, used by this export
881 ; occs' <- check_occs ie occs names
882 -- This check_occs not only finds conflicts
883 -- between this item and others, but also
884 -- internally within this item. That is, if
885 -- 'M.x' is in scope in several ways, we'll have
886 -- several members of mod_avails with the same
888 ; return (L loc (IEModuleContents mod) : ie_names,
889 occs', map greAvail gres ++ exports) }
891 exports_from_item acc@(lie_names, occs, exports) (L loc ie)
893 = do new_ie <- lookup_doc_ie ie
894 return (L loc new_ie : lie_names, occs, exports)
897 = do (new_ie, avail) <- lookup_ie ie
898 if isUnboundName (ieName new_ie)
899 then return acc -- Avoid error cascade
902 occs' <- check_occs ie occs (availNames avail)
904 return (L loc new_ie : lie_names, occs', avail : exports)
907 lookup_ie :: IE RdrName -> RnM (IE Name, AvailInfo)
908 lookup_ie (IEVar rdr)
909 = do gre <- lookupGreRn rdr
910 return (IEVar (gre_name gre), greAvail gre)
912 lookup_ie (IEThingAbs rdr)
913 = do gre <- lookupGreRn rdr
914 let name = gre_name gre
916 NoParent -> return (IEThingAbs name,
918 ParentIs p -> return (IEThingAbs name,
921 lookup_ie ie@(IEThingAll rdr)
922 = do name <- lookupGlobalOccRn rdr
923 let kids = findChildren kids_env name
924 mkKidRdrName = case isQual_maybe rdr of
925 Nothing -> mkRdrUnqual
926 Just (modName, _) -> mkRdrQual modName
927 addUsedRdrNames $ map (mkKidRdrName . nameOccName) kids
928 warnDodgyExports <- doptM Opt_WarnDodgyExports
931 then when warnDodgyExports $ addWarn (dodgyExportWarn name)
932 else -- This occurs when you export T(..), but
933 -- only import T abstractly, or T is a synonym.
934 addErr (exportItemErr ie)
936 return (IEThingAll name, AvailTC name (name:kids))
938 lookup_ie ie@(IEThingWith rdr sub_rdrs)
939 = do name <- lookupGlobalOccRn rdr
940 if isUnboundName name
941 then return (IEThingWith name [], AvailTC name [name])
943 let env = mkOccEnv [ (nameOccName s, s)
944 | s <- findChildren kids_env name ]
945 mb_names = map (lookupOccEnv env . rdrNameOcc) sub_rdrs
946 if any isNothing mb_names
947 then do addErr (exportItemErr ie)
948 return (IEThingWith name [], AvailTC name [name])
949 else do let names = catMaybes mb_names
950 optTyFam <- doptM Opt_TypeFamilies
951 when (not optTyFam && any isTyConName names) $
952 addErr (typeItemErr ( head
955 (text "in export list"))
956 return (IEThingWith name names, AvailTC name (name:names))
958 lookup_ie _ = panic "lookup_ie" -- Other cases covered earlier
961 lookup_doc_ie :: IE RdrName -> RnM (IE Name)
962 lookup_doc_ie (IEGroup lev doc) = do rn_doc <- rnHsDoc doc
963 return (IEGroup lev rn_doc)
964 lookup_doc_ie (IEDoc doc) = do rn_doc <- rnHsDoc doc
965 return (IEDoc rn_doc)
966 lookup_doc_ie (IEDocNamed str) = return (IEDocNamed str)
967 lookup_doc_ie _ = panic "lookup_doc_ie" -- Other cases covered earlier
970 isDoc :: IE RdrName -> Bool
971 isDoc (IEDoc _) = True
972 isDoc (IEDocNamed _) = True
973 isDoc (IEGroup _ _) = True
976 -------------------------------
977 isModuleExported :: Bool -> ModuleName -> GlobalRdrElt -> Bool
978 -- True if the thing is in scope *both* unqualified, *and* with qualifier M
979 isModuleExported implicit_prelude mod (GRE { gre_name = name, gre_prov = prov })
980 | implicit_prelude && isBuiltInSyntax name = False
981 -- Optimisation: filter out names for built-in syntax
982 -- They just clutter up the environment (esp tuples), and the parser
983 -- will generate Exact RdrNames for them, so the cluttered
984 -- envt is no use. To avoid doing this filter all the time,
985 -- we use -XNoImplicitPrelude as a clue that the filter is
986 -- worth while. Really, it's only useful for GHC.Base and GHC.Tuple.
988 -- It's worth doing because it makes the environment smaller for
989 -- every module that imports the Prelude
992 LocalDef | Just name_mod <- nameModule_maybe name
993 -> moduleName name_mod == mod
995 Imported is -> any unQualSpecOK is && any (qualSpecOK mod) is
997 -------------------------------
998 check_occs :: IE RdrName -> ExportOccMap -> [Name] -> RnM ExportOccMap
999 check_occs ie occs names
1000 = foldlM check occs names
1003 = case lookupOccEnv occs name_occ of
1004 Nothing -> return (extendOccEnv occs name_occ (name, ie))
1007 | name == name' -- Duplicate export
1008 -> do { warn_dup_exports <- doptM Opt_WarnDuplicateExports ;
1009 warnIf warn_dup_exports (dupExportWarn name_occ ie ie') ;
1012 | otherwise -- Same occ name but different names: an error
1013 -> do { global_env <- getGlobalRdrEnv ;
1014 addErr (exportClashErr global_env name' name ie' ie) ;
1017 name_occ = nameOccName name
1020 %*********************************************************
1024 %*********************************************************
1027 finishWarnings :: DynFlags -> Maybe WarningTxt
1028 -> TcGblEnv -> RnM TcGblEnv
1029 -- (a) Report usage of imports that are deprecated or have other warnings
1030 -- (b) If the whole module is warned about or deprecated, update tcg_warns
1031 -- All this happens only once per module
1032 finishWarnings dflags mod_warn tcg_env
1033 = do { (eps,hpt) <- getEpsAndHpt
1034 ; ifOptM Opt_WarnWarningsDeprecations $
1035 mapM_ (check hpt (eps_PIT eps)) all_gres
1036 -- By this time, typechecking is complete,
1037 -- so the PIT is fully populated
1039 -- Deal with a module deprecation; it overrides all existing warns
1040 ; let new_warns = case mod_warn of
1041 Just txt -> WarnAll txt
1042 Nothing -> tcg_warns tcg_env
1043 ; return (tcg_env { tcg_warns = new_warns }) }
1045 used_names = allUses (tcg_dus tcg_env)
1046 -- Report on all deprecated uses; hence allUses
1047 all_gres = globalRdrEnvElts (tcg_rdr_env tcg_env)
1049 check hpt pit gre@(GRE {gre_name = name, gre_prov = Imported (imp_spec:_)})
1050 | name `elemNameSet` used_names
1051 , Just deprec_txt <- lookupImpDeprec dflags hpt pit gre
1052 = addWarnAt (importSpecLoc imp_spec)
1053 (sep [ptext (sLit "In the use of") <+>
1054 pprNonVarNameSpace (occNameSpace (nameOccName name)) <+>
1056 (parens imp_msg) <> colon,
1059 name_mod = ASSERT2( isExternalName name, ppr name ) nameModule name
1060 imp_mod = importSpecModule imp_spec
1061 imp_msg = ptext (sLit "imported from") <+> ppr imp_mod <> extra
1062 extra | imp_mod == moduleName name_mod = empty
1063 | otherwise = ptext (sLit ", but defined in") <+> ppr name_mod
1065 check _ _ _ = return () -- Local, or not used, or not deprectated
1066 -- The Imported pattern-match: don't deprecate locally defined names
1067 -- For a start, we may be exporting a deprecated thing
1068 -- Also we may use a deprecated thing in the defn of another
1069 -- deprecated things. We may even use a deprecated thing in
1070 -- the defn of a non-deprecated thing, when changing a module's
1073 lookupImpDeprec :: DynFlags -> HomePackageTable -> PackageIfaceTable
1074 -> GlobalRdrElt -> Maybe WarningTxt
1075 -- The name is definitely imported, so look in HPT, PIT
1076 lookupImpDeprec dflags hpt pit gre
1077 = case lookupIfaceByModule dflags hpt pit mod of
1078 Just iface -> mi_warn_fn iface name `mplus` -- Bleat if the thing, *or
1080 ParentIs p -> mi_warn_fn iface p -- its parent*, is warn'd
1083 Nothing -> Nothing -- See Note [Used names with interface not loaded]
1086 mod = ASSERT2( isExternalName name, ppr name ) nameModule name
1089 Note [Used names with interface not loaded]
1090 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1091 By now all the interfaces should have been loaded,
1092 because reportDeprecations happens after typechecking.
1093 However, it's still (just) possible to to find a used
1094 Name whose interface hasn't been loaded:
1096 a) It might be a WiredInName; in that case we may not load
1097 its interface (although we could).
1099 b) It might be GHC.Real.fromRational, or GHC.Num.fromInteger
1100 These are seen as "used" by the renamer (if -XNoImplicitPrelude)
1101 is on), but the typechecker may discard their uses
1102 if in fact the in-scope fromRational is GHC.Read.fromRational,
1103 (see tcPat.tcOverloadedLit), and the typechecker sees that the type
1104 is fixed, say, to GHC.Base.Float (see Inst.lookupSimpleInst).
1105 In that obscure case it won't force the interface in.
1107 In both cases we simply don't permit deprecations;
1108 this is, after all, wired-in stuff.
1111 %*********************************************************
1115 %*********************************************************
1118 reportUnusedNames :: Maybe [LIE RdrName] -- Export list
1119 -> TcGblEnv -> RnM ()
1120 reportUnusedNames _export_decls gbl_env
1121 = do { traceRn ((text "RUN") <+> (ppr (tcg_dus gbl_env)))
1122 ; warnUnusedImportDecls gbl_env
1123 ; warnUnusedTopBinds unused_locals }
1125 used_names :: NameSet
1126 used_names = findUses (tcg_dus gbl_env) emptyNameSet
1127 -- NB: currently, if f x = g, we only treat 'g' as used if 'f' is used
1130 -- Collect the defined names from the in-scope environment
1131 defined_names :: [GlobalRdrElt]
1132 defined_names = globalRdrEnvElts (tcg_rdr_env gbl_env)
1134 -- Note that defined_and_used, defined_but_not_used
1135 -- are both [GRE]; that's why we need defined_and_used
1136 -- rather than just used_names
1137 _defined_and_used, defined_but_not_used :: [GlobalRdrElt]
1138 (_defined_and_used, defined_but_not_used)
1139 = partition (gre_is_used used_names) defined_names
1141 kids_env = mkChildEnv defined_names
1142 -- This is done in mkExports too; duplicated work
1144 gre_is_used :: NameSet -> GlobalRdrElt -> Bool
1145 gre_is_used used_names (GRE {gre_name = name})
1146 = name `elemNameSet` used_names
1147 || any (`elemNameSet` used_names) (findChildren kids_env name)
1148 -- A use of C implies a use of T,
1149 -- if C was brought into scope by T(..) or T(C)
1151 -- Filter out the ones that are
1152 -- (a) defined in this module, and
1153 -- (b) not defined by a 'deriving' clause
1154 -- The latter have an Internal Name, so we can filter them out easily
1155 unused_locals :: [GlobalRdrElt]
1156 unused_locals = filter is_unused_local defined_but_not_used
1157 is_unused_local :: GlobalRdrElt -> Bool
1158 is_unused_local gre = isLocalGRE gre && isExternalName (gre_name gre)
1161 %*********************************************************
1165 %*********************************************************
1167 This code finds which import declarations are unused. The
1168 specification and implementation notes are here:
1169 http://hackage.haskell.org/trac/ghc/wiki/Commentary/Compiler/UnusedImports
1172 type ImportDeclUsage
1173 = ( LImportDecl Name -- The import declaration
1174 , [AvailInfo] -- What *is* used (normalised)
1175 , [Name] ) -- What is imported but *not* used
1179 warnUnusedImportDecls :: TcGblEnv -> RnM ()
1180 warnUnusedImportDecls gbl_env
1181 = do { uses <- readMutVar (tcg_used_rdrnames gbl_env)
1182 ; let imports = filter explicit_import (tcg_rn_imports gbl_env)
1183 rdr_env = tcg_rdr_env gbl_env
1185 ; let usage :: [ImportDeclUsage]
1186 usage = findImportUsage imports rdr_env (Set.elems uses)
1188 ; ifOptM Opt_WarnUnusedImports $
1189 mapM_ warnUnusedImport usage
1191 ; ifOptM Opt_D_dump_minimal_imports $
1192 printMinimalImports usage }
1194 explicit_import (L loc _) = isGoodSrcSpan loc
1195 -- Filter out the implicit Prelude import
1196 -- which we do not want to bleat about
1200 findImportUsage :: [LImportDecl Name]
1203 -> [ImportDeclUsage]
1205 type ImportMap = FiniteMap SrcLoc [AvailInfo]
1206 -- The intermediate data struture records, for each import
1207 -- declaration, what stuff brought into scope by that
1208 -- declaration is actually used in the module.
1210 -- The SrcLoc is the location of the start
1211 -- of a particular 'import' declaration
1213 -- The AvailInfos are the things imported from that decl
1214 -- (just a list, not normalised)
1216 findImportUsage imports rdr_env rdrs
1217 = map unused_decl imports
1219 import_usage :: ImportMap
1220 import_usage = foldr add_rdr emptyFM rdrs
1222 unused_decl decl@(L loc (ImportDecl { ideclHiding = imps }))
1223 = (decl, nubAvails used_avails, unused_imps)
1225 used_avails = lookupFM import_usage (srcSpanStart loc) `orElse` []
1226 used_names = availsToNameSet used_avails
1228 unused_imps = case imps of
1229 Just (False, imp_ies) -> nameSetToList unused_imps
1231 imp_names = mkNameSet (concatMap (ieNames . unLoc) imp_ies)
1232 unused_imps = imp_names `minusNameSet` used_names
1234 _other -> [] -- No explicit import list => no unused-name list
1236 add_rdr :: RdrName -> ImportMap -> ImportMap
1238 = case lookupGRE_RdrName rdr rdr_env of
1239 [gre] | Imported imps <- gre_prov gre
1240 -> add_imp gre (bestImport imps) iu
1243 add_imp :: GlobalRdrElt -> ImportSpec -> ImportMap -> ImportMap
1244 add_imp gre (ImpSpec { is_decl = imp_decl_spec }) iu
1245 = addToFM_C add iu decl_loc [avail]
1247 add avails _ = avail : avails
1248 decl_loc = srcSpanStart (is_dloc imp_decl_spec)
1250 avail = case gre_par gre of
1251 ParentIs p -> AvailTC p [p,name]
1252 NoParent | isTyConName name -> AvailTC name [name]
1253 | otherwise -> Avail name
1254 -- If you use (+) from Num, then for this purpose we want
1255 -- to say that Num is used as well. That is why in the
1256 -- ParentIs case we have [p,name] in the ParentIs case
1258 bestImport :: [ImportSpec] -> ImportSpec
1260 = case partition isImpAll iss of
1261 ([], imp_somes) -> textuallyFirst imp_somes
1262 (imp_alls, _) -> textuallyFirst imp_alls
1264 textuallyFirst :: [ImportSpec] -> ImportSpec
1265 textuallyFirst iss = case sortWith (is_dloc . is_decl) iss of
1266 [] -> pprPanic "textuallyFirst" (ppr iss)
1269 isImpAll :: ImportSpec -> Bool
1270 isImpAll (ImpSpec { is_item = ImpAll }) = True
1271 isImpAll _other = False
1275 warnUnusedImport :: ImportDeclUsage -> RnM ()
1276 warnUnusedImport (L loc decl, used, unused)
1277 | Just (False,[]) <- ideclHiding decl
1278 = return () -- Do not warn for 'import M()'
1279 | null used = addWarnAt loc msg1 -- Nothing used; drop entire decl
1280 | null unused = return () -- Everything imported is used; nop
1281 | otherwise = addWarnAt loc msg2 -- Some imports are unused
1283 msg1 = vcat [pp_herald <+> quotes pp_mod <+> pp_not_used,
1284 nest 2 (ptext (sLit "except perhaps to import instances from")
1286 ptext (sLit "To import instances alone, use:")
1287 <+> ptext (sLit "import") <+> pp_mod <> parens empty ]
1288 msg2 = sep [pp_herald <+> quotes (pprWithCommas ppr unused),
1289 text "from module" <+> quotes pp_mod <+> pp_not_used]
1290 pp_herald = text "The import of"
1291 pp_mod = ppr (unLoc (ideclName decl))
1292 pp_not_used = text "is redundant"
1295 To print the minimal imports we walk over the user-supplied import
1296 decls, and simply trim their import lists. NB that
1298 * We do *not* change the 'qualified' or 'as' parts!
1300 * We do not disard a decl altogether; we might need instances
1301 from it. Instead we just trim to an empty import list
1304 printMinimalImports :: [ImportDeclUsage] -> RnM ()
1305 printMinimalImports imports_w_usage
1306 = do { imports' <- mapM mk_minimal imports_w_usage
1307 ; this_mod <- getModule
1309 do { h <- openFile (mkFilename this_mod) WriteMode
1310 ; printForUser h neverQualify (vcat (map ppr imports')) }
1311 -- The neverQualify is important. We are printing Names
1312 -- but they are in the context of an 'import' decl, and
1313 -- we never qualify things inside there
1314 -- E.g. import Blag( f, b )
1315 -- not import Blag( Blag.f, Blag.g )!
1318 mkFilename this_mod = moduleNameString (moduleName this_mod) ++ ".imports"
1320 mk_minimal (L l decl, used, unused)
1322 , Just (False, _) <- ideclHiding decl
1325 = do { ies <- initIfaceTcRn $ mapM to_ie used
1326 ; return (L l (decl { ideclHiding = Just (False, map (L l) ies) })) }
1328 to_ie :: AvailInfo -> IfG (IE Name)
1329 -- The main trick here is that if we're importing all the constructors
1330 -- we want to say "T(..)", but if we're importing only a subset we want
1331 -- to say "T(A,B,C)". So we have to find out what the module exports.
1332 to_ie (Avail n) = return (IEVar n)
1333 to_ie (AvailTC n [m]) = ASSERT( n==m )
1334 return (IEThingAbs n)
1335 to_ie (AvailTC n ns) = do
1336 iface <- loadSysInterface doc n_mod
1337 case [xs | (m,as) <- mi_exports iface,
1340 x == nameOccName n] of
1341 [xs] | all_used xs -> return (IEThingAll n)
1342 | otherwise -> return (IEThingWith n (filter (/= n) ns))
1343 other -> pprTrace "to_ie" (ppr n <+> ppr n_mod <+> ppr other) $
1346 all_used avail_occs = all (`elem` map nameOccName ns) avail_occs
1347 doc = text "Compute minimal imports from" <+> ppr n
1348 n_mod = ASSERT( isExternalName n ) nameModule n
1351 %************************************************************************
1355 %************************************************************************
1358 qualImportItemErr :: RdrName -> SDoc
1359 qualImportItemErr rdr
1360 = hang (ptext (sLit "Illegal qualified name in import item:"))
1363 badImportItemErr :: ModIface -> ImpDeclSpec -> IE RdrName -> SDoc
1364 badImportItemErr iface decl_spec ie
1365 = sep [ptext (sLit "Module"), quotes (ppr (is_mod decl_spec)), source_import,
1366 ptext (sLit "does not export"), quotes (ppr ie)]
1368 source_import | mi_boot iface = ptext (sLit "(hi-boot interface)")
1371 illegalImportItemErr :: SDoc
1372 illegalImportItemErr = ptext (sLit "Illegal import item")
1374 dodgyImportWarn :: RdrName -> SDoc
1375 dodgyImportWarn item = dodgyMsg (ptext (sLit "import")) item
1376 dodgyExportWarn :: Name -> SDoc
1377 dodgyExportWarn item = dodgyMsg (ptext (sLit "export")) item
1379 dodgyMsg :: OutputableBndr n => SDoc -> n -> SDoc
1381 = sep [ ptext (sLit "The") <+> kind <+> ptext (sLit "item") <+> quotes (ppr (IEThingAll tc))
1382 <+> ptext (sLit "suggests that"),
1383 quotes (ppr tc) <+> ptext (sLit "has (in-scope) constructors or class methods,"),
1384 ptext (sLit "but it has none") ]
1386 exportItemErr :: IE RdrName -> SDoc
1387 exportItemErr export_item
1388 = sep [ ptext (sLit "The export item") <+> quotes (ppr export_item),
1389 ptext (sLit "attempts to export constructors or class methods that are not visible here") ]
1391 typeItemErr :: Name -> SDoc -> SDoc
1392 typeItemErr name wherestr
1393 = sep [ ptext (sLit "Using 'type' tag on") <+> quotes (ppr name) <+> wherestr,
1394 ptext (sLit "Use -XTypeFamilies to enable this extension") ]
1396 exportClashErr :: GlobalRdrEnv -> Name -> Name -> IE RdrName -> IE RdrName
1398 exportClashErr global_env name1 name2 ie1 ie2
1399 = vcat [ ptext (sLit "Conflicting exports for") <+> quotes (ppr occ) <> colon
1400 , ppr_export ie1' name1'
1401 , ppr_export ie2' name2' ]
1403 occ = nameOccName name1
1404 ppr_export ie name = nest 2 (quotes (ppr ie) <+> ptext (sLit "exports") <+>
1405 quotes (ppr name) <+> pprNameProvenance (get_gre name))
1407 -- get_gre finds a GRE for the Name, so that we can show its provenance
1409 = case lookupGRE_Name global_env name of
1411 [] -> pprPanic "exportClashErr" (ppr name)
1412 get_loc name = nameSrcLoc $ gre_name $ get_gre name
1413 (name1', ie1', name2', ie2') = if get_loc name1 < get_loc name2
1414 then (name1, ie1, name2, ie2)
1415 else (name2, ie2, name1, ie1)
1417 addDupDeclErr :: [Name] -> TcRn ()
1419 = panic "addDupDeclErr: empty list"
1420 addDupDeclErr names@(name : _)
1421 = addErrAt (getSrcSpan (last sorted_names)) $
1422 -- Report the error at the later location
1423 vcat [ptext (sLit "Multiple declarations of") <+> quotes (ppr name),
1424 ptext (sLit "Declared at:") <+> vcat (map (ppr . nameSrcLoc) sorted_names)]
1426 sorted_names = sortWith nameSrcLoc names
1428 dupExportWarn :: OccName -> IE RdrName -> IE RdrName -> SDoc
1429 dupExportWarn occ_name ie1 ie2
1430 = hsep [quotes (ppr occ_name),
1431 ptext (sLit "is exported by"), quotes (ppr ie1),
1432 ptext (sLit "and"), quotes (ppr ie2)]
1434 dupModuleExport :: ModuleName -> SDoc
1436 = hsep [ptext (sLit "Duplicate"),
1437 quotes (ptext (sLit "Module") <+> ppr mod),
1438 ptext (sLit "in export list")]
1440 moduleNotImported :: ModuleName -> SDoc
1441 moduleNotImported mod
1442 = ptext (sLit "The export item `module") <+> ppr mod <>
1443 ptext (sLit "' is not imported")
1445 nullModuleExport :: ModuleName -> SDoc
1446 nullModuleExport mod
1447 = ptext (sLit "The export item `module") <+> ppr mod <> ptext (sLit "' exports nothing")
1449 moduleWarn :: ModuleName -> WarningTxt -> SDoc
1450 moduleWarn mod (WarningTxt txt)
1451 = sep [ ptext (sLit "Module") <+> quotes (ppr mod) <> ptext (sLit ":"),
1452 nest 2 (vcat (map ppr txt)) ]
1453 moduleWarn mod (DeprecatedTxt txt)
1454 = sep [ ptext (sLit "Module") <+> quotes (ppr mod)
1455 <+> ptext (sLit "is deprecated:"),
1456 nest 2 (vcat (map ppr txt)) ]
1458 implicitPreludeWarn :: SDoc
1460 = ptext (sLit "Module `Prelude' implicitly imported")
1462 packageImportErr :: SDoc
1464 = ptext (sLit "Package-qualified imports are not enabled; use -XPackageImports")