2 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
4 \section[RnNames]{Extracting imported and top-level names in scope}
8 rnImports, importsFromLocalDecls,
10 getLocalDeclBinders, extendRdrEnvRn,
11 reportUnusedNames, reportDeprecations
14 #include "HsVersions.h"
16 import DynFlags ( DynFlag(..), GhcMode(..), DynFlags(..) )
17 import HsSyn ( IE(..), ieName, ImportDecl(..), LImportDecl,
18 ForeignDecl(..), HsGroup(..), HsValBinds(..),
19 Sig(..), collectHsBindLocatedBinders, tyClDeclNames,
20 instDeclATs, isIdxTyDecl,
23 import RnHsDoc ( rnHsDoc )
24 import IfaceEnv ( ifaceExportNames )
25 import LoadIface ( loadSrcInterface )
26 import TcRnMonad hiding (LIE)
41 import BasicTypes ( DeprecTxt )
42 import DriverPhases ( isHsBoot )
45 import Data.List ( partition, concatMap, (\\), delete )
46 import IO ( openFile, IOMode(..) )
52 %************************************************************************
56 %************************************************************************
59 rnImports :: [LImportDecl RdrName]
60 -> RnM ([LImportDecl Name], GlobalRdrEnv, ImportAvails)
63 -- PROCESS IMPORT DECLS
64 -- Do the non {- SOURCE -} ones first, so that we get a helpful
65 -- warning for {- SOURCE -} ones that are unnecessary
66 = do this_mod <- getModule
67 implicit_prelude <- doptM Opt_ImplicitPrelude
68 let prel_imports = mkPrelImports this_mod implicit_prelude imports
69 (source, ordinary) = partition is_source_import imports
70 is_source_import (L _ (ImportDecl _ is_boot _ _ _)) = is_boot
72 stuff1 <- mapM (rnImportDecl this_mod) (prel_imports ++ ordinary)
73 stuff2 <- mapM (rnImportDecl this_mod) source
74 let (decls, rdr_env, imp_avails) = combine (stuff1 ++ stuff2)
75 return (decls, rdr_env, imp_avails)
78 combine :: [(LImportDecl Name, GlobalRdrEnv, ImportAvails)]
79 -> ([LImportDecl Name], GlobalRdrEnv, ImportAvails)
80 combine = foldr plus ([], emptyGlobalRdrEnv, emptyImportAvails)
81 where plus (decl, gbl_env1, imp_avails1)
82 (decls, gbl_env2, imp_avails2)
84 gbl_env1 `plusGlobalRdrEnv` gbl_env2,
85 imp_avails1 `plusImportAvails` imp_avails2)
87 mkPrelImports :: Module -> Bool -> [LImportDecl RdrName] -> [LImportDecl RdrName]
88 -- Consruct the implicit declaration "import Prelude" (or not)
90 -- NB: opt_NoImplicitPrelude is slightly different to import Prelude ();
91 -- because the former doesn't even look at Prelude.hi for instance
92 -- declarations, whereas the latter does.
93 mkPrelImports this_mod implicit_prelude import_decls
95 || explicit_prelude_import
96 || not implicit_prelude
98 | otherwise = [preludeImportDecl]
100 explicit_prelude_import
101 = notNull [ () | L _ (ImportDecl mod _ _ _ _) <- import_decls,
102 unLoc mod == pRELUDE_NAME ]
104 preludeImportDecl :: LImportDecl RdrName
107 ImportDecl (L loc pRELUDE_NAME)
108 False {- Not a boot interface -}
109 False {- Not qualified -}
110 Nothing {- No "as" -}
111 Nothing {- No import list -}
113 loc = mkGeneralSrcSpan FSLIT("Implicit import declaration")
116 rnImportDecl :: Module
117 -> LImportDecl RdrName
118 -> RnM (LImportDecl Name, GlobalRdrEnv, ImportAvails)
120 rnImportDecl this_mod (L loc (ImportDecl loc_imp_mod_name want_boot
121 qual_only as_mod imp_details))
125 -- If there's an error in loadInterface, (e.g. interface
126 -- file not found) we get lots of spurious errors from 'filterImports'
128 imp_mod_name = unLoc loc_imp_mod_name
129 doc = ppr imp_mod_name <+> ptext SLIT("is directly imported")
131 iface <- loadSrcInterface doc imp_mod_name want_boot
133 -- Compiler sanity check: if the import didn't say
134 -- {-# SOURCE #-} we should not get a hi-boot file
135 WARN( not want_boot && mi_boot iface, ppr imp_mod_name ) (do
137 -- Issue a user warning for a redundant {- SOURCE -} import
138 -- NB that we arrange to read all the ordinary imports before
139 -- any of the {- SOURCE -} imports
140 warnIf (want_boot && not (mi_boot iface))
141 (warnRedundantSourceImport imp_mod_name)
144 imp_mod = mi_module iface
145 deprecs = mi_deprecs iface
146 is_orph = mi_orphan iface
147 has_finsts = mi_finsts iface
150 filtered_exports = filter not_this_mod (mi_exports iface)
151 not_this_mod (mod,_) = mod /= this_mod
152 -- If the module exports anything defined in this module, just
153 -- ignore it. Reason: otherwise it looks as if there are two
154 -- local definition sites for the thing, and an error gets
155 -- reported. Easiest thing is just to filter them out up
156 -- front. This situation only arises if a module imports
157 -- itself, or another module that imported it. (Necessarily,
158 -- this invoves a loop.)
160 -- Tiresome consequence: if you say
165 -- module B( AType ) where
166 -- import {-# SOURCE #-} A( AType )
168 -- then you'll get a 'B does not export AType' message. Oh well.
170 qual_mod_name = case as_mod of
171 Nothing -> imp_mod_name
172 Just another_name -> another_name
173 imp_spec = ImpDeclSpec { is_mod = imp_mod_name, is_qual = qual_only,
174 is_dloc = loc, is_as = qual_mod_name }
177 -- Get the total exports from this module
178 total_avails <- ifaceExportNames filtered_exports
180 -- filter the imports according to the import declaration
181 (new_imp_details, gbl_env) <-
182 filterImports iface imp_spec imp_details total_avails
187 -- Compute new transitive dependencies
189 orphans | is_orph = ASSERT( not (imp_mod `elem` dep_orphs deps) )
190 imp_mod : dep_orphs deps
191 | otherwise = dep_orphs deps
193 finsts | has_finsts = ASSERT( not (imp_mod `elem` dep_finsts deps) )
194 imp_mod : dep_finsts deps
195 | otherwise = dep_finsts deps
197 pkg = modulePackageId (mi_module iface)
199 (dependent_mods, dependent_pkgs)
200 | pkg == thisPackage dflags =
201 -- Imported module is from the home package
202 -- Take its dependent modules and add imp_mod itself
203 -- Take its dependent packages unchanged
205 -- NB: (dep_mods deps) might include a hi-boot file
206 -- for the module being compiled, CM. Do *not* filter
207 -- this out (as we used to), because when we've
208 -- finished dealing with the direct imports we want to
209 -- know if any of them depended on CM.hi-boot, in
210 -- which case we should do the hi-boot consistency
211 -- check. See LoadIface.loadHiBootInterface
212 ((imp_mod_name, want_boot) : dep_mods deps, dep_pkgs deps)
215 -- Imported module is from another package
216 -- Dump the dependent modules
217 -- Add the package imp_mod comes from to the dependent packages
218 ASSERT2( not (pkg `elem` dep_pkgs deps), ppr pkg <+> ppr (dep_pkgs deps) )
219 ([], pkg : dep_pkgs deps)
221 -- True <=> import M ()
222 import_all = case imp_details of
223 Just (is_hiding, ls) -> not is_hiding && null ls
226 imports = ImportAvails {
227 imp_mods = unitModuleEnv imp_mod (imp_mod, import_all, loc),
230 imp_dep_mods = mkModDeps dependent_mods,
231 imp_dep_pkgs = dependent_pkgs
234 -- Complain if we import a deprecated module
235 ifOptM Opt_WarnDeprecations (
237 DeprecAll txt -> addWarn (moduleDeprec imp_mod_name txt)
241 let new_imp_decl = L loc (ImportDecl loc_imp_mod_name want_boot
242 qual_only as_mod new_imp_details)
244 returnM (new_imp_decl, gbl_env, imports)
247 warnRedundantSourceImport mod_name
248 = ptext SLIT("Unnecessary {-# SOURCE #-} in the import of module")
249 <+> quotes (ppr mod_name)
253 %************************************************************************
255 importsFromLocalDecls
257 %************************************************************************
259 From the top-level declarations of this module produce
260 * the lexical environment
262 created by its bindings.
264 Complain about duplicate bindings
267 importsFromLocalDecls :: HsGroup RdrName -> RnM TcGblEnv
268 importsFromLocalDecls group
269 = do { gbl_env <- getGblEnv
271 ; avails <- getLocalDeclBinders gbl_env group
273 ; rdr_env' <- extendRdrEnvRn (tcg_rdr_env gbl_env) avails
275 ; traceRn (text "local avails: " <> ppr avails)
277 ; returnM (gbl_env { tcg_rdr_env = rdr_env' })
280 extendRdrEnvRn :: GlobalRdrEnv -> [AvailInfo] -> RnM GlobalRdrEnv
281 -- Add the new locally-bound names one by one, checking for duplicates as
282 -- we do so. Remember that in Template Haskell the duplicates
283 -- might *already be* in the GlobalRdrEnv from higher up the module
284 extendRdrEnvRn rdr_env avails
285 = foldlM add_local rdr_env (gresFromAvails LocalDef avails)
287 add_local rdr_env gre
288 | gres <- lookupGlobalRdrEnv rdr_env (nameOccName (gre_name gre))
289 , (dup_gre:_) <- filter isLocalGRE gres -- Check for existing *local* defns
290 = do { addDupDeclErr (gre_name dup_gre) (gre_name gre)
293 = return (extendGlobalRdrEnv rdr_env gre)
296 @getLocalDeclBinders@ returns the names for an @HsDecl@. It's
297 used for source code.
299 *** See "THE NAMING STORY" in HsDecls ****
301 Instances of indexed types
302 ~~~~~~~~~~~~~~~~~~~~~~~~~~
303 Indexed data/newtype instances contain data constructors that we need to
304 collect, too. Moreover, we need to descend into the data/newtypes instances
305 of associated families.
307 We need to be careful with the handling of the type constructor of each type
308 instance as the family constructor is already defined, and we want to avoid
309 raising a duplicate declaration error. So, we make a new name for it, but
310 don't return it in the 'AvailInfo'.
313 getLocalDeclBinders :: TcGblEnv -> HsGroup RdrName -> RnM [AvailInfo]
314 getLocalDeclBinders gbl_env (HsGroup {hs_valds = ValBindsIn val_decls val_sigs,
315 hs_tyclds = tycl_decls,
316 hs_instds = inst_decls,
317 hs_fords = foreign_decls })
318 = do { tc_names_s <- mappM new_tc tycl_decls
319 ; at_names_s <- mappM inst_ats inst_decls
320 ; val_names <- mappM new_simple val_bndrs
321 ; return (val_names ++ tc_names_s ++ concat at_names_s) }
323 mod = tcg_mod gbl_env
324 is_hs_boot = isHsBoot (tcg_src gbl_env) ;
325 val_bndrs | is_hs_boot = sig_hs_bndrs
326 | otherwise = for_hs_bndrs ++ val_hs_bndrs
327 -- In a hs-boot file, the value binders come from the
328 -- *signatures*, and there should be no foreign binders
330 new_simple rdr_name = do
331 nm <- newTopSrcBinder mod rdr_name
334 sig_hs_bndrs = [nm | L _ (TypeSig nm _) <- val_sigs]
335 val_hs_bndrs = collectHsBindLocatedBinders val_decls
336 for_hs_bndrs = [nm | L _ (ForeignImport nm _ _) <- foreign_decls]
339 | isIdxTyDecl (unLoc tc_decl)
340 = do { main_name <- lookupFamInstDeclBndr mod main_rdr
341 ; sub_names <- mappM (newTopSrcBinder mod) sub_rdrs
342 ; return (AvailTC main_name sub_names) }
343 -- main_name is not bound here!
345 = do { main_name <- newTopSrcBinder mod main_rdr
346 ; sub_names <- mappM (newTopSrcBinder mod) sub_rdrs
347 ; return (AvailTC main_name (main_name : sub_names)) }
349 (main_rdr : sub_rdrs) = tyClDeclNames (unLoc tc_decl)
352 = mappM new_tc (instDeclATs (unLoc inst_decl))
354 getLocalDeclBinders _ _ = panic "getLocalDeclBinders" -- ValBindsOut can't happen
358 %************************************************************************
360 \subsection{Filtering imports}
362 %************************************************************************
364 @filterImports@ takes the @ExportEnv@ telling what the imported module makes
365 available, and filters it through the import spec (if any).
368 filterImports :: ModIface
369 -> ImpDeclSpec -- The span for the entire import decl
370 -> Maybe (Bool, [LIE RdrName]) -- Import spec; True => hiding
371 -> [AvailInfo] -- What's available
372 -> RnM (Maybe (Bool, [LIE Name]), -- Import spec w/ Names
373 GlobalRdrEnv) -- Same again, but in GRE form
375 filterImports iface decl_spec Nothing all_avails
376 = return (Nothing, mkGlobalRdrEnv (gresFromAvails prov all_avails))
378 prov = Imported [ImpSpec { is_decl = decl_spec, is_item = ImpAll }]
381 filterImports iface decl_spec (Just (want_hiding, import_items)) all_avails
382 = do -- check for errors, convert RdrNames to Names
383 opt_indexedtypes <- doptM Opt_IndexedTypes
384 items1 <- mapM (lookup_lie opt_indexedtypes) import_items
386 let items2 :: [(LIE Name, AvailInfo)]
387 items2 = concat items1
388 -- NB the AvailInfo may have duplicates, and several items
389 -- for the same parent; e.g N(x) and N(y)
391 names = availsToNameSet (map snd items2)
392 keep n = not (n `elemNameSet` names)
393 pruned_avails = filterAvails keep all_avails
394 hiding_prov = Imported [ImpSpec { is_decl = decl_spec, is_item = ImpAll }]
396 gres | want_hiding = gresFromAvails hiding_prov pruned_avails
397 | otherwise = concatMap (gresFromIE decl_spec) items2
399 return (Just (want_hiding, map fst items2), mkGlobalRdrEnv gres)
401 -- This environment is how we map names mentioned in the import
402 -- list to the actual Name they correspond to, and the name family
403 -- that the Name belongs to (the AvailInfo). The situation is
404 -- complicated by associated families, which introduce a three-level
405 -- hierachy, where class = grand parent, assoc family = parent, and
406 -- data constructors = children. The occ_env entries for associated
407 -- families needs to capture all this information; hence, we have the
408 -- third component of the environment that gives the class name (=
409 -- grand parent) in case of associated families.
411 -- This env will have entries for data constructors too,
412 -- they won't make any difference because naked entities like T
413 -- in an import list map to TcOccs, not VarOccs.
414 occ_env :: OccEnv (Name, -- the name
415 AvailInfo, -- the export item providing the name
416 Maybe Name) -- the parent of associated types
417 occ_env = mkOccEnv_C combine [ (nameOccName n, (n, a, Nothing))
418 | a <- all_avails, n <- availNames a]
420 -- we know that (1) there are at most entries for one name, (2) their
421 -- first component is identical, (3) they are for tys/cls, and (4) one
422 -- entry has the name in its parent position (the other doesn't)
423 combine (name, AvailTC p1 subs1, Nothing)
424 (_ , AvailTC p2 subs2, Nothing)
426 (parent, subs) = if p1 == name then (p2, subs1) else (p1, subs2)
428 (name, AvailTC name subs, Just parent)
430 lookup_lie :: Bool -> LIE RdrName -> TcRn [(LIE Name, AvailInfo)]
431 lookup_lie opt_indexedtypes (L loc ieRdr)
433 stuff <- setSrcSpan loc $
434 case lookup_ie opt_indexedtypes ieRdr of
435 Failed err -> addErr err >> return []
436 Succeeded a -> return a
437 checkDodgyImport stuff
438 return [ (L loc ie, avail) | (ie,avail) <- stuff ]
440 -- Warn when importing T(..) if T was exported abstractly
441 checkDodgyImport stuff
442 | IEThingAll n <- ieRdr, (_, AvailTC _ [one]):_ <- stuff
443 = ifOptM Opt_WarnDodgyImports (addWarn (dodgyImportWarn n))
444 -- NB. use the RdrName for reporting the warning
448 -- For each import item, we convert its RdrNames to Names,
449 -- and at the same time construct an AvailInfo corresponding
450 -- to what is actually imported by this item.
451 -- Returns Nothing on error.
452 -- We return a list here, because in the case of an import
453 -- item like C, if we are hiding, then C refers to *both* a
454 -- type/class and a data constructor. Moreover, when we import
455 -- data constructors of an associated family, we need separate
456 -- AvailInfos for the data constructors and the family (as they have
457 -- different parents). See the discussion at occ_env.
458 lookup_ie :: Bool -> IE RdrName -> MaybeErr Message [(IE Name,AvailInfo)]
459 lookup_ie opt_indexedtypes ie
460 = let bad_ie = Failed (badImportItemErr iface decl_spec ie)
462 lookup_name rdrName =
463 case lookupOccEnv occ_env (rdrNameOcc rdrName) of
469 (name, avail, _) <- lookup_name n
470 return [(IEVar name, trimAvail avail name)]
473 (name, avail@(AvailTC name2 subs), mb_parent) <- lookup_name tc
475 -- non-associated ty/cls
476 Nothing -> return [(IEThingAll name, avail)]
478 Just parent -> return [(IEThingAll name,
479 AvailTC name2 (subs \\ [name])),
480 (IEThingAll name, AvailTC parent [name])]
483 | want_hiding -- hiding ( C )
484 -- Here the 'C' can be a data constructor
485 -- *or* a type/class, or even both
486 -> let tc_name = lookup_name tc
487 dc_name = lookup_name (setRdrNameSpace tc srcDataName)
489 case catMaybeErr [ tc_name, dc_name ] of
491 names -> return [mkIEThingAbs name | name <- names]
493 -> do nameAvail <- lookup_name tc
494 return [mkIEThingAbs nameAvail]
496 IEThingWith tc ns -> do
497 (name, AvailTC name2 subnames, mb_parent) <- lookup_name tc
499 env = mkOccEnv [(nameOccName s, s) | s <- subnames]
500 mb_children = map (lookupOccEnv env . rdrNameOcc) ns
501 children <- if any isNothing mb_children
503 else return (catMaybes mb_children)
504 -- check for proper import of indexed types
505 when (not opt_indexedtypes && any isTyConName children) $
506 Failed (typeItemErr (head . filter isTyConName $ children)
507 (text "in import list"))
509 -- non-associated ty/cls
510 Nothing -> return [(IEThingWith name children,
511 AvailTC name (name:children))]
513 Just parent -> return [(IEThingWith name children,
514 AvailTC name children),
515 (IEThingWith name children,
516 AvailTC parent [name])]
518 _other -> Failed illegalImportItemErr
519 -- could be IEModuleContents, IEGroup, IEDoc, IEDocNamed
523 mkIEThingAbs (n, av, Nothing ) = (IEThingAbs n, trimAvail av n)
524 mkIEThingAbs (n, av, Just parent) = (IEThingAbs n, AvailTC parent [n])
527 catMaybeErr :: [MaybeErr err a] -> [a]
528 catMaybeErr ms = [ a | Succeeded a <- ms ]
531 %************************************************************************
535 %************************************************************************
538 -- | make a 'GlobalRdrEnv' where all the elements point to the same
539 -- import declaration (useful for "hiding" imports, or imports with
541 gresFromAvails :: Provenance -> [AvailInfo] -> [GlobalRdrElt]
542 gresFromAvails prov avails
543 = concatMap (gresFromAvail (const prov)) avails
545 gresFromAvail :: (Name -> Provenance) -> AvailInfo -> [GlobalRdrElt]
546 gresFromAvail prov_fn avail
547 = [ GRE {gre_name = n,
548 gre_par = availParent n avail,
549 gre_prov = prov_fn n}
550 | n <- availNames avail ]
552 greAvail :: GlobalRdrElt -> AvailInfo
553 greAvail gre = mkUnitAvail (gre_name gre) (gre_par gre)
555 mkUnitAvail :: Name -> Parent -> AvailInfo
556 mkUnitAvail me (ParentIs p) = AvailTC p [me]
557 mkUnitAvail me NoParent | isTyConName me = AvailTC me [me]
558 | otherwise = Avail me
560 plusAvail (Avail n1) (Avail n2) = Avail n1
561 plusAvail (AvailTC n1 ns1) (AvailTC n2 ns2) = AvailTC n2 (ns1 `unionLists` ns2)
562 plusAvail a1 a2 = pprPanic "RnEnv.plusAvail" (hsep [ppr a1,ppr a2])
564 availParent :: Name -> AvailInfo -> Parent
565 availParent n (Avail _) = NoParent
566 availParent n (AvailTC m ms) | n==m = NoParent
567 | otherwise = ParentIs m
569 trimAvail :: AvailInfo -> Name -> AvailInfo
570 trimAvail (Avail n) m = Avail n
571 trimAvail (AvailTC n ns) m = ASSERT( m `elem` ns) AvailTC n [m]
573 -- | filters 'AvailInfo's by the given predicate
574 filterAvails :: (Name -> Bool) -> [AvailInfo] -> [AvailInfo]
575 filterAvails keep avails = foldr (filterAvail keep) [] avails
577 -- | filters an 'AvailInfo' by the given predicate
578 filterAvail :: (Name -> Bool) -> AvailInfo -> [AvailInfo] -> [AvailInfo]
579 filterAvail keep ie rest =
581 Avail n | keep n -> ie : rest
584 let left = filter keep ns in
585 if null left then rest else AvailTC tc left : rest
587 -- | Given an import/export spec, construct the appropriate 'GlobalRdrElt's.
588 gresFromIE :: ImpDeclSpec -> (LIE Name, AvailInfo) -> [GlobalRdrElt]
589 gresFromIE decl_spec (L loc ie, avail)
590 = gresFromAvail prov_fn avail
592 is_explicit = case ie of
593 IEThingAll name -> \n -> n==name
595 prov_fn name = Imported [imp_spec]
597 imp_spec = ImpSpec { is_decl = decl_spec, is_item = item_spec }
598 item_spec = ImpSome { is_explicit = is_explicit name, is_iloc = loc }
600 mkChildEnv :: [GlobalRdrElt] -> NameEnv [Name]
601 mkChildEnv gres = foldr add emptyNameEnv gres
603 add (GRE { gre_name = n, gre_par = ParentIs p }) env = extendNameEnv_C (++) env p [n]
604 add other_gre env = env
606 findChildren :: NameEnv [Name] -> Name -> [Name]
607 findChildren env n = lookupNameEnv env n `orElse` []
610 ---------------------------------------
613 All this AvailEnv stuff is hardly used; only in a very small
614 part of RnNames. Todo: remove?
615 ---------------------------------------
618 type AvailEnv = NameEnv AvailInfo -- Maps a Name to the AvailInfo that contains it
620 emptyAvailEnv :: AvailEnv
621 emptyAvailEnv = emptyNameEnv
623 unitAvailEnv :: AvailInfo -> AvailEnv
624 unitAvailEnv a = unitNameEnv (availName a) a
626 plusAvailEnv :: AvailEnv -> AvailEnv -> AvailEnv
627 plusAvailEnv = plusNameEnv_C plusAvail
629 availEnvElts :: AvailEnv -> [AvailInfo]
630 availEnvElts = nameEnvElts
632 addAvail :: AvailEnv -> AvailInfo -> AvailEnv
633 addAvail avails avail = extendNameEnv_C plusAvail avails (availName avail) avail
635 mkAvailEnv :: [AvailInfo] -> AvailEnv
636 -- 'avails' may have several items with the same availName
637 -- E.g import Ix( Ix(..), index )
638 -- will give Ix(Ix,index,range) and Ix(index)
639 -- We want to combine these; addAvail does that
640 mkAvailEnv avails = foldl addAvail emptyAvailEnv avails
642 -- After combining the avails, we need to ensure that the parent name is the
643 -- first entry in the list of subnames, if it is included at all. (Subsequent
644 -- functions rely on that.)
645 normaliseAvail :: AvailInfo -> AvailInfo
646 normaliseAvail avail@(Avail _) = avail
647 normaliseAvail (AvailTC name subs) = AvailTC name subs'
649 subs' = if name `elem` subs then name : (delete name subs) else subs
651 -- | combines 'AvailInfo's from the same family
652 nubAvails :: [AvailInfo] -> [AvailInfo]
653 nubAvails avails = map normaliseAvail . nameEnvElts . mkAvailEnv $ avails
657 %************************************************************************
659 \subsection{Export list processing}
661 %************************************************************************
663 Processing the export list.
665 You might think that we should record things that appear in the export
666 list as ``occurrences'' (using @addOccurrenceName@), but you'd be
667 wrong. We do check (here) that they are in scope, but there is no
668 need to slurp in their actual declaration (which is what
669 @addOccurrenceName@ forces).
671 Indeed, doing so would big trouble when compiling @PrelBase@, because
672 it re-exports @GHC@, which includes @takeMVar#@, whose type includes
673 @ConcBase.StateAndSynchVar#@, and so on...
676 type ExportAccum -- The type of the accumulating parameter of
677 -- the main worker function in rnExports
678 = ([LIE Name], -- Export items with Names
679 ExportOccMap, -- Tracks exported occurrence names
680 [AvailInfo]) -- The accumulated exported stuff
683 emptyExportAccum = ([], emptyOccEnv, [])
685 type ExportOccMap = OccEnv (Name, IE RdrName)
686 -- Tracks what a particular exported OccName
687 -- in an export list refers to, and which item
688 -- it came from. It's illegal to export two distinct things
689 -- that have the same occurrence name
691 rnExports :: Bool -- False => no 'module M(..) where' header at all
692 -> Maybe [LIE RdrName] -- Nothing => no explicit export list
693 -> RnM (Maybe [LIE Name], [AvailInfo])
695 -- Complains if two distinct exports have same OccName
696 -- Warns about identical exports.
697 -- Complains about exports items not in scope
699 rnExports explicit_mod exports
700 = do TcGblEnv { tcg_mod = this_mod,
701 tcg_rdr_env = rdr_env,
702 tcg_imports = imports } <- getGblEnv
704 -- If the module header is omitted altogether, then behave
705 -- as if the user had written "module Main(main) where..."
706 -- EXCEPT in interactive mode, when we behave as if he had
707 -- written "module Main where ..."
708 -- Reason: don't want to complain about 'main' not in scope
709 -- in interactive mode
710 ghc_mode <- getGhcMode
715 | ghc_mode == Interactive
718 -> do mainName <- lookupGlobalOccRn main_RDR_Unqual
719 return (Just ([noLoc (IEVar main_RDR_Unqual)]))
720 -- ToDo: the 'noLoc' here is unhelpful if 'main' turns
721 -- out to be out of scope
723 (exp_spec, avails) <- exports_from_avail real_exports rdr_env imports this_mod
725 return (exp_spec, nubAvails avails) -- Combine families
727 exports_from_avail :: Maybe [LIE RdrName]
728 -- Nothing => no explicit export list
732 -> RnM (Maybe [LIE Name], [AvailInfo])
734 exports_from_avail Nothing rdr_env imports this_mod
735 = -- The same as (module M) where M is the current module name,
736 -- so that's how we handle it.
738 avails = [ greAvail gre | gre <- globalRdrEnvElts rdr_env,
741 return (Nothing, avails)
743 exports_from_avail (Just rdr_items) rdr_env imports this_mod
744 = do (ie_names, _, exports) <- foldlM do_litem emptyExportAccum rdr_items
746 return (Just ie_names, exports)
748 do_litem :: ExportAccum -> LIE RdrName -> RnM ExportAccum
749 do_litem acc lie = setSrcSpan (getLoc lie) (exports_from_item acc lie)
751 kids_env :: NameEnv [Name] -- Maps a parent to its in-scope children
752 kids_env = mkChildEnv (globalRdrEnvElts rdr_env)
754 exports_from_item :: ExportAccum -> LIE RdrName -> RnM ExportAccum
755 exports_from_item acc@(ie_names, occs, exports)
756 (L loc ie@(IEModuleContents mod))
757 | let earlier_mods = [ mod | (L _ (IEModuleContents mod)) <- ie_names ]
758 , mod `elem` earlier_mods -- Duplicate export of M
759 = do { warn_dup_exports <- doptM Opt_WarnDuplicateExports ;
760 warnIf warn_dup_exports (dupModuleExport mod) ;
764 = do { implicit_prelude <- doptM Opt_ImplicitPrelude
765 ; let gres = filter (isModuleExported implicit_prelude mod)
766 (globalRdrEnvElts rdr_env)
768 ; warnIf (null gres) (nullModuleExport mod)
770 ; occs' <- check_occs ie occs (map gre_name gres)
771 -- This check_occs not only finds conflicts
772 -- between this item and others, but also
773 -- internally within this item. That is, if
774 -- 'M.x' is in scope in several ways, we'll have
775 -- several members of mod_avails with the same
777 ; return (L loc (IEModuleContents mod) : ie_names,
778 occs', map greAvail gres ++ exports) }
780 exports_from_item acc@(lie_names, occs, exports) (L loc ie)
782 = do new_ie <- lookup_doc_ie ie
783 return (L loc new_ie : lie_names, occs, exports)
786 = do (new_ie, avail) <- lookup_ie ie
787 if isUnboundName (ieName new_ie)
788 then return acc -- Avoid error cascade
791 occs' <- check_occs ie occs (availNames avail)
793 return (L loc new_ie : lie_names, occs', avail : exports)
796 lookup_ie :: IE RdrName -> RnM (IE Name, AvailInfo)
797 lookup_ie (IEVar rdr)
798 = do gre <- lookupGreRn rdr
799 return (IEVar (gre_name gre), greAvail gre)
801 lookup_ie (IEThingAbs rdr)
802 = do gre <- lookupGreRn rdr
803 let name = gre_name gre
805 NoParent -> return (IEThingAbs name,
807 ParentIs p -> return (IEThingAbs name,
810 lookup_ie ie@(IEThingAll rdr)
811 = do name <- lookupGlobalOccRn rdr
812 let kids = findChildren kids_env name
814 (if (isTyConName name) then addWarn (dodgyExportWarn name)
815 -- This occurs when you export T(..), but
816 -- only import T abstractly, or T is a synonym.
817 else addErr (exportItemErr ie))
819 return (IEThingAll name, AvailTC name (name:kids))
821 lookup_ie ie@(IEThingWith rdr sub_rdrs)
822 = do name <- lookupGlobalOccRn rdr
823 if isUnboundName name
824 then return (IEThingWith name [], AvailTC name [name])
826 let env = mkOccEnv [ (nameOccName s, s)
827 | s <- findChildren kids_env name ]
828 mb_names = map (lookupOccEnv env . rdrNameOcc) sub_rdrs
829 if any isNothing mb_names
830 then do addErr (exportItemErr ie)
831 return (IEThingWith name [], AvailTC name [name])
832 else do let names = catMaybes mb_names
833 optIdxTypes <- doptM Opt_IndexedTypes
834 when (not optIdxTypes && any isTyConName names) $
835 addErr (typeItemErr ( head
838 (text "in export list"))
839 return (IEThingWith name names, AvailTC name (name:names))
841 lookup_ie ie = panic "lookup_ie" -- Other cases covered earlier
844 lookup_doc_ie :: IE RdrName -> RnM (IE Name)
845 lookup_doc_ie (IEGroup lev doc) = do rn_doc <- rnHsDoc doc
846 return (IEGroup lev rn_doc)
847 lookup_doc_ie (IEDoc doc) = do rn_doc <- rnHsDoc doc
848 return (IEDoc rn_doc)
849 lookup_doc_ie (IEDocNamed str) = return (IEDocNamed str)
850 lookup_doc_ie ie = panic "lookup_doc_ie" -- Other cases covered earlier
853 isDoc (IEDoc _) = True
854 isDoc (IEDocNamed _) = True
855 isDoc (IEGroup _ _) = True
858 -------------------------------
859 isModuleExported :: Bool -> ModuleName -> GlobalRdrElt -> Bool
860 -- True if the thing is in scope *both* unqualified, *and* with qualifier M
861 isModuleExported implicit_prelude mod (GRE { gre_name = name, gre_prov = prov })
862 | implicit_prelude && isBuiltInSyntax name = False
863 -- Optimisation: filter out names for built-in syntax
864 -- They just clutter up the environment (esp tuples), and the parser
865 -- will generate Exact RdrNames for them, so the cluttered
866 -- envt is no use. To avoid doing this filter all the time,
867 -- we use -fno-implicit-prelude as a clue that the filter is
868 -- worth while. Really, it's only useful for GHC.Base and GHC.Tuple.
870 -- It's worth doing because it makes the environment smaller for
871 -- every module that imports the Prelude
874 LocalDef -> moduleName (nameModule name) == mod
875 Imported is -> any unQualSpecOK is && any (qualSpecOK mod) is
877 -------------------------------
878 check_occs :: IE RdrName -> ExportOccMap -> [Name] -> RnM ExportOccMap
879 check_occs ie occs names
880 = foldlM check occs names
883 = case lookupOccEnv occs name_occ of
884 Nothing -> returnM (extendOccEnv occs name_occ (name, ie))
887 | name == name' -- Duplicate export
888 -> do { warn_dup_exports <- doptM Opt_WarnDuplicateExports ;
889 warnIf warn_dup_exports (dupExportWarn name_occ ie ie') ;
892 | otherwise -- Same occ name but different names: an error
893 -> do { global_env <- getGlobalRdrEnv ;
894 addErr (exportClashErr global_env name' name ie' ie) ;
897 name_occ = nameOccName name
900 %*********************************************************
904 %*********************************************************
907 reportDeprecations :: DynFlags -> TcGblEnv -> RnM ()
908 reportDeprecations dflags tcg_env
909 = ifOptM Opt_WarnDeprecations $
910 do { (eps,hpt) <- getEpsAndHpt
911 -- By this time, typechecking is complete,
912 -- so the PIT is fully populated
913 ; mapM_ (check hpt (eps_PIT eps)) all_gres }
915 used_names = allUses (tcg_dus tcg_env)
916 -- Report on all deprecated uses; hence allUses
917 all_gres = globalRdrEnvElts (tcg_rdr_env tcg_env)
919 check hpt pit gre@(GRE {gre_name = name, gre_prov = Imported (imp_spec:_)})
920 | name `elemNameSet` used_names
921 , Just deprec_txt <- lookupDeprec dflags hpt pit gre
922 = addWarnAt (importSpecLoc imp_spec)
923 (sep [ptext SLIT("Deprecated use of") <+>
924 pprNonVarNameSpace (occNameSpace (nameOccName name)) <+>
926 (parens imp_msg) <> colon,
929 name_mod = nameModule name
930 imp_mod = importSpecModule imp_spec
931 imp_msg = ptext SLIT("imported from") <+> ppr imp_mod <> extra
932 extra | imp_mod == moduleName name_mod = empty
933 | otherwise = ptext SLIT(", but defined in") <+> ppr name_mod
935 check hpt pit ok_gre = returnM () -- Local, or not used, or not deprectated
936 -- The Imported pattern-match: don't deprecate locally defined names
937 -- For a start, we may be exporting a deprecated thing
938 -- Also we may use a deprecated thing in the defn of another
939 -- deprecated things. We may even use a deprecated thing in
940 -- the defn of a non-deprecated thing, when changing a module's
943 lookupDeprec :: DynFlags -> HomePackageTable -> PackageIfaceTable
944 -> GlobalRdrElt -> Maybe DeprecTxt
945 lookupDeprec dflags hpt pit gre
946 = case lookupIfaceByModule dflags hpt pit (nameModule name) of
947 Just iface -> mi_dep_fn iface name `seqMaybe` -- Bleat if the thing, *or
949 ParentIs p -> mi_dep_fn iface p -- its parent*, is deprec'd
952 | isWiredInName name -> Nothing
953 -- We have not necessarily loaded the .hi file for a
954 -- wired-in name (yet), although we *could*.
955 -- And we never deprecate them
957 | otherwise -> pprPanic "lookupDeprec" (ppr name)
958 -- By now all the interfaces should have been loaded
963 %*********************************************************
967 %*********************************************************
970 reportUnusedNames :: Maybe [LIE RdrName] -- Export list
971 -> TcGblEnv -> RnM ()
972 reportUnusedNames export_decls gbl_env
973 = do { traceRn ((text "RUN") <+> (ppr (tcg_dus gbl_env)))
974 ; warnUnusedTopBinds unused_locals
975 ; warnUnusedModules unused_imp_mods
976 ; warnUnusedImports unused_imports
977 ; warnDuplicateImports defined_and_used
978 ; printMinimalImports minimal_imports }
980 used_names :: NameSet
981 used_names = findUses (tcg_dus gbl_env) emptyNameSet
982 -- NB: currently, if f x = g, we only treat 'g' as used if 'f' is used
985 -- Collect the defined names from the in-scope environment
986 defined_names :: [GlobalRdrElt]
987 defined_names = globalRdrEnvElts (tcg_rdr_env gbl_env)
989 -- Note that defined_and_used, defined_but_not_used
990 -- are both [GRE]; that's why we need defined_and_used
991 -- rather than just used_names
992 defined_and_used, defined_but_not_used :: [GlobalRdrElt]
993 (defined_and_used, defined_but_not_used)
994 = partition (gre_is_used used_names) defined_names
996 kids_env = mkChildEnv defined_names
997 -- This is done in mkExports too; duplicated work
999 gre_is_used :: NameSet -> GlobalRdrElt -> Bool
1000 gre_is_used used_names (GRE {gre_name = name})
1001 = name `elemNameSet` used_names
1002 || any (`elemNameSet` used_names) (findChildren kids_env name)
1003 -- A use of C implies a use of T,
1004 -- if C was brought into scope by T(..) or T(C)
1006 -- Filter out the ones that are
1007 -- (a) defined in this module, and
1008 -- (b) not defined by a 'deriving' clause
1009 -- The latter have an Internal Name, so we can filter them out easily
1010 unused_locals :: [GlobalRdrElt]
1011 unused_locals = filter is_unused_local defined_but_not_used
1012 is_unused_local :: GlobalRdrElt -> Bool
1013 is_unused_local gre = isLocalGRE gre && isExternalName (gre_name gre)
1015 unused_imports :: [GlobalRdrElt]
1016 unused_imports = filter unused_imp defined_but_not_used
1017 unused_imp (GRE {gre_prov = Imported imp_specs})
1018 = not (all (module_unused . importSpecModule) imp_specs)
1019 && or [exp | ImpSpec { is_item = ImpSome { is_explicit = exp } } <- imp_specs]
1020 -- Don't complain about unused imports if we've already said the
1021 -- entire import is unused
1022 unused_imp other = False
1024 -- To figure out the minimal set of imports, start with the things
1025 -- that are in scope (i.e. in gbl_env). Then just combine them
1026 -- into a bunch of avails, so they are properly grouped
1028 -- BUG WARNING: this does not deal properly with qualified imports!
1029 minimal_imports :: FiniteMap ModuleName AvailEnv
1030 minimal_imports0 = foldr add_expall emptyFM expall_mods
1031 minimal_imports1 = foldr add_name minimal_imports0 defined_and_used
1032 minimal_imports = foldr add_inst_mod minimal_imports1 direct_import_mods
1033 -- The last line makes sure that we retain all direct imports
1034 -- even if we import nothing explicitly.
1035 -- It's not necessarily redundant to import such modules. Consider
1039 -- The import M() is not *necessarily* redundant, even if
1040 -- we suck in no instance decls from M (e.g. it contains
1041 -- no instance decls, or This contains no code). It may be
1042 -- that we import M solely to ensure that M's orphan instance
1043 -- decls (or those in its imports) are visible to people who
1044 -- import This. Sigh.
1045 -- There's really no good way to detect this, so the error message
1046 -- in RnEnv.warnUnusedModules is weakened instead
1048 -- We've carefully preserved the provenance so that we can
1049 -- construct minimal imports that import the name by (one of)
1050 -- the same route(s) as the programmer originally did.
1051 add_name gre@(GRE {gre_prov = Imported (imp_spec:_)}) acc
1052 = addToFM_C plusAvailEnv acc
1053 (importSpecModule imp_spec) (unitAvailEnv (greAvail gre))
1054 add_name gre acc = acc -- Local
1056 -- Modules mentioned as 'module M' in the export list
1057 expall_mods = case export_decls of
1059 Just es -> [m | L _ (IEModuleContents m) <- es]
1061 -- This is really bogus. The idea is that if we see 'module M' in
1062 -- the export list we must retain the import decls that drive it
1063 -- If we aren't careful we might see
1064 -- module A( module M ) where
1067 -- and suppose that N exports everything that M does. Then we
1068 -- must not drop the import of M even though N brings it all into
1071 -- BUG WARNING: 'module M' exports aside, what if M.x is mentioned?!
1073 -- The reason that add_expall is bogus is that it doesn't take
1074 -- qualified imports into account. But it's an improvement.
1075 add_expall mod acc = addToFM_C plusAvailEnv acc mod emptyAvailEnv
1077 add_inst_mod (mod,_,_) acc
1078 | mod_name `elemFM` acc = acc -- We import something already
1079 | otherwise = addToFM acc mod_name emptyAvailEnv
1081 mod_name = moduleName mod
1082 -- Add an empty collection of imports for a module
1083 -- from which we have sucked only instance decls
1085 imports = tcg_imports gbl_env
1087 direct_import_mods :: [(Module, Bool, SrcSpan)]
1088 -- See the type of the imp_mods for this triple
1089 direct_import_mods = moduleEnvElts (imp_mods imports)
1091 -- unused_imp_mods are the directly-imported modules
1092 -- that are not mentioned in minimal_imports1
1093 -- [Note: not 'minimal_imports', because that includes directly-imported
1094 -- modules even if we use nothing from them; see notes above]
1096 -- BUG WARNING: does not deal correctly with multiple imports of the same module
1097 -- becuase direct_import_mods has only one entry per module
1098 unused_imp_mods = [(mod_name,loc) | (mod,no_imp,loc) <- direct_import_mods,
1099 let mod_name = moduleName mod,
1100 not (mod_name `elemFM` minimal_imports1),
1103 -- The not no_imp part is not to complain about
1104 -- import M (), which is an idiom for importing
1105 -- instance declarations
1107 module_unused :: ModuleName -> Bool
1108 module_unused mod = any (((==) mod) . fst) unused_imp_mods
1110 ---------------------
1111 warnDuplicateImports :: [GlobalRdrElt] -> RnM ()
1112 -- Given the GREs for names that are used, figure out which imports
1113 -- could be omitted without changing the top-level environment.
1115 -- NB: Given import Foo( T )
1116 -- import qualified Foo
1117 -- we do not report a duplicate import, even though Foo.T is brought
1118 -- into scope by both, because there's nothing you can *omit* without
1119 -- changing the top-level environment. So we complain only if it's
1120 -- explicitly named in both imports or neither.
1122 -- Furthermore, we complain about Foo.T only if
1123 -- there is no complaint about (unqualified) T
1125 warnDuplicateImports gres
1126 = ifOptM Opt_WarnUnusedImports $
1127 sequenceM_ [ warn name pr
1128 -- The 'head' picks the first offending group
1129 -- for this particular name
1130 | GRE { gre_name = name, gre_prov = Imported imps } <- gres
1131 , pr <- redundants imps ]
1133 warn name (red_imp, cov_imp)
1134 = addWarnAt (importSpecLoc red_imp)
1135 (vcat [ptext SLIT("Redundant import of:") <+> quotes pp_name,
1136 ptext SLIT("It is also") <+> ppr cov_imp])
1138 pp_name | is_qual red_decl = ppr (is_as red_decl) <> dot <> ppr occ
1139 | otherwise = ppr occ
1140 occ = nameOccName name
1141 red_decl = is_decl red_imp
1143 redundants :: [ImportSpec] -> [(ImportSpec,ImportSpec)]
1144 -- The returned pair is (redundant-import, covering-import)
1146 = [ (red_imp, cov_imp)
1148 , cov_imp <- take 1 (filter (covers red_imp) imps) ]
1150 -- "red_imp" is a putative redundant import
1151 -- "cov_imp" potentially covers it
1152 -- This test decides whether red_imp could be dropped
1154 -- NOTE: currently the test does not warn about
1157 -- even if the same underlying 'x' is involved, because dropping
1158 -- either import would change the qualified names in scope (M.x, N.x)
1159 -- But if the qualified names aren't used, the import is indeed redundant
1160 -- Sadly we don't know that. Oh well.
1161 covers red_imp@(ImpSpec { is_decl = red_decl, is_item = red_item })
1162 cov_imp@(ImpSpec { is_decl = cov_decl, is_item = cov_item })
1163 | red_loc == cov_loc
1164 = False -- Ignore diagonal elements
1165 | not (is_as red_decl == is_as cov_decl)
1166 = False -- They bring into scope different qualified names
1167 | not (is_qual red_decl) && is_qual cov_decl
1168 = False -- Covering one doesn't bring unqualified name into scope
1170 = not cov_selective -- Redundant one is selective and covering one isn't
1171 || red_later -- Both are explicit; tie-break using red_later
1173 = not cov_selective -- Neither import is selective
1174 && (is_mod red_decl == is_mod cov_decl) -- They import the same module
1175 && red_later -- Tie-break
1177 red_loc = importSpecLoc red_imp
1178 cov_loc = importSpecLoc cov_imp
1179 red_later = red_loc > cov_loc
1180 cov_selective = selectiveImpItem cov_item
1181 red_selective = selectiveImpItem red_item
1183 selectiveImpItem :: ImpItemSpec -> Bool
1184 selectiveImpItem ImpAll = False
1185 selectiveImpItem (ImpSome {}) = True
1187 -- ToDo: deal with original imports with 'qualified' and 'as M' clauses
1188 printMinimalImports :: FiniteMap ModuleName AvailEnv -- Minimal imports
1190 printMinimalImports imps
1191 = ifOptM Opt_D_dump_minimal_imports $ do {
1193 mod_ies <- mappM to_ies (fmToList imps) ;
1194 this_mod <- getModule ;
1195 rdr_env <- getGlobalRdrEnv ;
1196 ioToTcRn (do { h <- openFile (mkFilename this_mod) WriteMode ;
1197 printForUser h (mkPrintUnqualified rdr_env)
1198 (vcat (map ppr_mod_ie mod_ies)) })
1201 mkFilename this_mod = moduleNameString (moduleName this_mod) ++ ".imports"
1202 ppr_mod_ie (mod_name, ies)
1203 | mod_name == moduleName pRELUDE
1205 | null ies -- Nothing except instances comes from here
1206 = ptext SLIT("import") <+> ppr mod_name <> ptext SLIT("() -- Instances only")
1208 = ptext SLIT("import") <+> ppr mod_name <>
1209 parens (fsep (punctuate comma (map ppr ies)))
1211 to_ies (mod, avail_env) = do ies <- mapM to_ie (availEnvElts avail_env)
1214 to_ie :: AvailInfo -> RnM (IE Name)
1215 -- The main trick here is that if we're importing all the constructors
1216 -- we want to say "T(..)", but if we're importing only a subset we want
1217 -- to say "T(A,B,C)". So we have to find out what the module exports.
1218 to_ie (Avail n) = returnM (IEVar n)
1219 to_ie (AvailTC n [m]) = ASSERT( n==m )
1220 returnM (IEThingAbs n)
1221 to_ie (AvailTC n ns)
1222 = loadSrcInterface doc n_mod False `thenM` \ iface ->
1223 case [xs | (m,as) <- mi_exports iface,
1224 moduleName m == n_mod,
1226 x == nameOccName n] of
1227 [xs] | all_used xs -> returnM (IEThingAll n)
1228 | otherwise -> returnM (IEThingWith n (filter (/= n) ns))
1229 other -> pprTrace "to_ie" (ppr n <+> ppr n_mod <+> ppr other) $
1232 all_used avail_occs = all (`elem` map nameOccName ns) avail_occs
1233 doc = text "Compute minimal imports from" <+> ppr n
1234 n_mod = moduleName (nameModule n)
1238 %************************************************************************
1242 %************************************************************************
1245 badImportItemErr iface decl_spec ie
1246 = sep [ptext SLIT("Module"), quotes (ppr (is_mod decl_spec)), source_import,
1247 ptext SLIT("does not export"), quotes (ppr ie)]
1249 source_import | mi_boot iface = ptext SLIT("(hi-boot interface)")
1252 illegalImportItemErr = ptext SLIT("Illegal import item")
1254 dodgyImportWarn item = dodgyMsg (ptext SLIT("import")) item
1255 dodgyExportWarn item = dodgyMsg (ptext SLIT("export")) item
1258 = sep [ ptext SLIT("The") <+> kind <+> ptext SLIT("item") <+> quotes (ppr (IEThingAll tc)),
1259 ptext SLIT("suggests that") <+> quotes (ppr tc) <+> ptext SLIT("has constructor or class methods"),
1260 ptext SLIT("but it has none; it is a type synonym or abstract type or class") ]
1262 exportItemErr export_item
1263 = sep [ ptext SLIT("The export item") <+> quotes (ppr export_item),
1264 ptext SLIT("attempts to export constructors or class methods that are not visible here") ]
1266 typeItemErr name wherestr
1267 = sep [ ptext SLIT("Using 'type' tag on") <+> quotes (ppr name) <+> wherestr,
1268 ptext SLIT("Use -findexed-types to enable this extension") ]
1270 exportClashErr global_env name1 name2 ie1 ie2
1271 = vcat [ ptext SLIT("Conflicting exports for") <+> quotes (ppr occ) <> colon
1272 , ppr_export ie1 name1
1273 , ppr_export ie2 name2 ]
1275 occ = nameOccName name1
1276 ppr_export ie name = nest 2 (quotes (ppr ie) <+> ptext SLIT("exports") <+>
1277 quotes (ppr name) <+> pprNameProvenance (get_gre name))
1279 -- get_gre finds a GRE for the Name, so that we can show its provenance
1281 = case lookupGRE_Name global_env name of
1283 [] -> pprPanic "exportClashErr" (ppr name)
1285 addDupDeclErr :: Name -> Name -> TcRn ()
1286 addDupDeclErr name_a name_b
1287 = addErrAt (srcLocSpan loc2) $
1288 vcat [ptext SLIT("Multiple declarations of") <+> quotes (ppr name1),
1289 ptext SLIT("Declared at:") <+> vcat [ppr (nameSrcLoc name1), ppr loc2]]
1291 loc2 = nameSrcLoc name2
1292 (name1,name2) | nameSrcLoc name_a > nameSrcLoc name_b = (name_b,name_a)
1293 | otherwise = (name_a,name_b)
1294 -- Report the error at the later location
1296 dupExportWarn occ_name ie1 ie2
1297 = hsep [quotes (ppr occ_name),
1298 ptext SLIT("is exported by"), quotes (ppr ie1),
1299 ptext SLIT("and"), quotes (ppr ie2)]
1302 = hsep [ptext SLIT("Duplicate"),
1303 quotes (ptext SLIT("Module") <+> ppr mod),
1304 ptext SLIT("in export list")]
1306 nullModuleExport mod
1307 = ptext SLIT("The export item `module") <+> ppr mod <> ptext SLIT("' exports nothing")
1309 moduleDeprec mod txt
1310 = sep [ ptext SLIT("Module") <+> quotes (ppr mod) <+> ptext SLIT("is deprecated:"),