2 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
4 \section{Dealing with interface files}
8 readIface, findAndReadIface, loadInterface, loadHomeInterface,
9 tryLoadInterface, loadOrphanModules,
10 loadExports, loadFixDecls, loadDeprecs,
17 #include "HsVersions.h"
19 import DriverState ( GhcMode(..), v_GhcMode )
20 import DriverUtil ( splitFilename )
21 import CmdLineOpts ( opt_IgnoreIfacePragmas )
22 import HscTypes ( ModuleLocation(..),
23 ModIface(..), emptyModIface,
24 VersionInfo(..), ImportedModuleInfo,
26 ImportVersion, WhetherHasOrphans, IsBootInterface,
27 DeclsMap, GatedDecl, IfaceInsts, IfaceRules,
28 AvailInfo, GenAvailInfo(..), Avails, Deprecations(..)
30 import HsSyn ( TyClDecl(..), InstDecl(..),
31 HsType(..), HsPred(..), FixitySig(..), RuleDecl(..),
32 tyClDeclNames, tyClDeclSysNames, hsTyVarNames, getHsInstHead,
34 import RdrHsSyn ( RdrNameTyClDecl, RdrNameInstDecl, RdrNameRuleDecl )
35 import RnHsSyn ( extractHsTyNames_s )
36 import BasicTypes ( Version, defaultFixity )
37 import RnTypes ( rnHsType )
40 import ParseIface ( parseIface )
42 import Name ( Name {-instance NamedThing-},
43 nameModule, isLocalName, nameIsLocalOrFrom
48 import RdrName ( rdrNameOcc )
49 import SrcLoc ( mkSrcLoc )
50 import Maybes ( maybeToBool, orElse )
51 import StringBuffer ( hGetStringBuffer )
52 import FastString ( mkFastString )
53 import ErrUtils ( Message )
54 import Finder ( findModule, findPackageModule )
57 import ListSetOps ( minusList )
67 %*********************************************************
69 \subsection{Loading a new interface file}
71 %*********************************************************
74 loadHomeInterface :: SDoc -> Name -> RnM d ModIface
75 loadHomeInterface doc_str name
76 = ASSERT2( not (isLocalName name), ppr name <+> parens doc_str )
77 loadInterface doc_str (moduleName (nameModule name)) ImportBySystem
79 loadOrphanModules :: [ModuleName] -> RnM d ()
80 loadOrphanModules mods
81 | null mods = returnRn ()
82 | otherwise = traceRn (text "Loading orphan modules:" <+>
83 fsep (map ppr mods)) `thenRn_`
84 mapRn_ load mods `thenRn_`
87 load mod = loadInterface (mk_doc mod) mod ImportBySystem
88 mk_doc mod = ppr mod <+> ptext SLIT("is a orphan-instance module")
90 loadInterface :: SDoc -> ModuleName -> WhereFrom -> RnM d ModIface
91 loadInterface doc mod from
92 = tryLoadInterface doc mod from `thenRn` \ (ifaces, maybe_err) ->
94 Nothing -> returnRn ifaces
95 Just err -> failWithRn ifaces (elaborate err)
97 elaborate err = hang (ptext SLIT("failed to load interface for") <+> quotes (ppr mod) <> colon)
100 tryLoadInterface :: SDoc -> ModuleName -> WhereFrom -> RnM d (ModIface, Maybe Message)
101 -- Returns (Just err) if an error happened
102 -- It *doesn't* add an error to the monad, because sometimes it's ok to fail...
103 -- Specifically, when we read the usage information from an interface file,
104 -- we try to read the interfaces it mentions. But it's OK to fail; perhaps
105 -- the module has changed, and that interface is no longer used.
107 -- tryLoadInterface guarantees to return with iImpModInfo m --> (..., True)
108 -- (If the load fails, we plug in a vanilla placeholder)
109 tryLoadInterface doc_str mod_name from
110 = getHomeIfaceTableRn `thenRn` \ hit ->
111 getModuleRn `thenRn` \ this_mod ->
112 getIfacesRn `thenRn` \ ifaces@(Ifaces { iPIT = pit }) ->
114 -- CHECK WHETHER WE HAVE IT ALREADY
115 case lookupIfaceByModName hit pit mod_name of {
116 Just iface | case from of
117 ImportByUser -> not (mi_boot iface)
118 ImportByUserSource -> mi_boot iface
119 ImportBySystem -> True
120 -> returnRn (iface, Nothing) ; -- Already loaded
121 -- The not (mi_boot iface) test checks that the already-loaded
122 -- interface isn't a boot iface. This can conceivably happen,
123 -- if the version checking happened to load a boot interface
124 -- before we got to real imports.
128 mod_map = iImpModInfo ifaces
129 mod_info = lookupFM mod_map mod_name
132 = case (from, mod_info) of
133 (ImportByUser, _) -> False -- Not hi-boot
134 (ImportByUserSource, _) -> True -- hi-boot
135 (ImportBySystem, Just (_, is_boot)) -> is_boot
136 (ImportBySystem, Nothing) -> False
137 -- We're importing a module we know absolutely
138 -- nothing about, so we assume it's from
139 -- another package, where we aren't doing
140 -- dependency tracking. So it won't be a hi-boot file.
142 redundant_source_import
143 = case (from, mod_info) of
144 (ImportByUserSource, Just (_,False)) -> True
148 -- Issue a warning for a redundant {- SOURCE -} import
149 -- NB that we arrange to read all the ordinary imports before
150 -- any of the {- SOURCE -} imports
151 warnCheckRn (not redundant_source_import)
152 (warnRedundantSourceImport mod_name) `thenRn_`
154 -- Check that we aren't importing ourselves.
155 -- That only happens in Rename.checkOldIface,
156 -- which doesn't call tryLoadInterface
158 (not (isHomeModule this_mod) || moduleName this_mod /= mod_name)
159 (warnSelfImport this_mod) `thenRn_`
161 -- READ THE MODULE IN
162 findAndReadIface doc_str mod_name hi_boot_file
163 `thenRn` \ read_result ->
164 case read_result of {
165 Left err -> -- Not found, so add an empty export env to the Ifaces map
166 -- so that we don't look again
168 fake_mod = mkVanillaModule mod_name
169 fake_iface = emptyModIface fake_mod
170 new_ifaces = ifaces { iPIT = extendModuleEnv pit fake_mod fake_iface }
172 setIfacesRn new_ifaces `thenRn_`
173 returnRn (fake_iface, Just err) ;
176 Right (mod, iface) ->
178 -- LOAD IT INTO Ifaces
180 -- NB: *first* we do loadDecl, so that the provenance of all the locally-defined
181 --- names is done correctly (notably, whether this is an .hi file or .hi-boot file).
182 -- If we do loadExport first the wrong info gets into the cache (unless we
183 -- explicitly tag each export which seems a bit of a bore)
186 -- Sanity check. If we're system-importing a module we know nothing at all
187 -- about, it should be from a different package to this one
188 WARN( not (maybeToBool mod_info) &&
189 case from of { ImportBySystem -> True; other -> False } &&
193 loadDecls mod (iDecls ifaces) (pi_decls iface) `thenRn` \ (decls_vers, new_decls) ->
194 loadRules mod (iRules ifaces) (pi_rules iface) `thenRn` \ (rule_vers, new_rules) ->
195 loadInstDecls mod (iInsts ifaces) (pi_insts iface) `thenRn` \ new_insts ->
196 loadExports (pi_exports iface) `thenRn` \ (export_vers, avails) ->
197 loadFixDecls mod (pi_fixity iface) `thenRn` \ fix_env ->
198 loadDeprecs mod (pi_deprecs iface) `thenRn` \ deprec_env ->
200 version = VersionInfo { vers_module = pi_vers iface,
201 vers_exports = export_vers,
202 vers_rules = rule_vers,
203 vers_decls = decls_vers }
205 -- For an explicit user import, add to mod_map info about
206 -- the things the imported module depends on, extracted
207 -- from its usage info; and delete the module itself, which is now in the PIT
208 mod_map1 = case from of
209 ImportByUser -> addModDeps mod is_loaded (pi_usages iface) mod_map
211 mod_map2 = delFromFM mod_map1 mod_name
213 this_mod_name = moduleName this_mod
214 is_loaded m = m == this_mod_name
215 || maybeToBool (lookupIfaceByModName hit pit m)
216 -- We treat the currently-being-compiled module as 'loaded' because
217 -- even though it isn't yet in the HIT or PIT; otherwise it gets
218 -- put into iImpModInfo, and then spat out into its own interface
219 -- file as a dependency
221 -- Now add info about this module to the PIT
222 has_orphans = pi_orphan iface
223 new_pit = extendModuleEnv pit mod mod_iface
224 mod_iface = ModIface { mi_module = mod, mi_version = version,
225 mi_orphan = has_orphans, mi_boot = hi_boot_file,
227 mi_fixities = fix_env, mi_deprecs = deprec_env,
228 mi_usages = [], -- Will be filled in later
229 mi_decls = panic "No mi_decls in PIT",
230 mi_globals = mkIfaceGlobalRdrEnv avails
233 new_ifaces = ifaces { iPIT = new_pit,
237 iImpModInfo = mod_map2 }
239 setIfacesRn new_ifaces `thenRn_`
240 returnRn (mod_iface, Nothing)
243 -----------------------------------------------------
244 -- Adding module dependencies from the
245 -- import decls in the interface file
246 -----------------------------------------------------
249 -> (ModuleName -> Bool) -- True for modules that are already loaded
251 -> ImportedModuleInfo -> ImportedModuleInfo
252 -- (addModDeps M ivs deps)
253 -- We are importing module M, and M.hi contains 'import' decls given by ivs
254 addModDeps mod is_loaded new_deps mod_deps
255 = foldr add mod_deps filtered_new_deps
257 -- Don't record dependencies when importing a module from another package
258 -- Except for its descendents which contain orphans,
259 -- and in that case, forget about the boot indicator
260 filtered_new_deps :: [(ModuleName, (WhetherHasOrphans, IsBootInterface))]
262 | isHomeModule mod = [ (imp_mod, (has_orphans, is_boot))
263 | (imp_mod, has_orphans, is_boot, _) <- new_deps,
264 not (is_loaded imp_mod)
266 | otherwise = [ (imp_mod, (True, False))
267 | (imp_mod, has_orphans, _, _) <- new_deps,
268 not (is_loaded imp_mod) && has_orphans
270 add (imp_mod, dep) deps = addToFM_C combine deps imp_mod dep
272 combine old@(old_has_orphans, old_is_boot) new@(new_has_orphans, new_is_boot)
273 | old_is_boot = new -- Record the best is_boot info
276 -----------------------------------------------------
277 -- Loading the export list
278 -----------------------------------------------------
280 loadExports :: (Version, [ExportItem]) -> RnM d (Version, [(ModuleName,Avails)])
281 loadExports (vers, items)
282 = mapRn loadExport items `thenRn` \ avails_s ->
283 returnRn (vers, avails_s)
286 loadExport :: ExportItem -> RnM d (ModuleName, Avails)
287 loadExport (mod, entities)
288 = mapRn (load_entity mod) entities `thenRn` \ avails ->
289 returnRn (mod, avails)
291 load_entity mod (Avail occ)
292 = newGlobalName mod occ `thenRn` \ name ->
293 returnRn (Avail name)
294 load_entity mod (AvailTC occ occs)
295 = newGlobalName mod occ `thenRn` \ name ->
296 mapRn (newGlobalName mod) occs `thenRn` \ names ->
297 returnRn (AvailTC name names)
300 -----------------------------------------------------
301 -- Loading type/class/value decls
302 -----------------------------------------------------
306 -> [(Version, RdrNameTyClDecl)]
307 -> RnM d (NameEnv Version, DeclsMap)
308 loadDecls mod (decls_map, n_slurped) decls
309 = foldlRn (loadDecl mod) (emptyNameEnv, decls_map) decls `thenRn` \ (vers, decls_map') ->
310 returnRn (vers, (decls_map', n_slurped))
312 loadDecl mod (version_map, decls_map) (version, decl)
313 = getTyClDeclBinders mod decl `thenRn` \ (avail, sys_names) ->
315 full_avail = case avail of
317 AvailTC n ns -> AvailTC n (sys_names ++ ns)
318 main_name = availName full_avail
319 new_decls_map = extendNameEnvList decls_map stuff
320 stuff = [ (name, (full_avail, name==main_name, (mod, decl)))
321 | name <- availNames full_avail]
323 new_version_map = extendNameEnv version_map main_name version
325 traceRn (text "Loading" <+> ppr full_avail) `thenRn_`
326 returnRn (new_version_map, new_decls_map)
328 -----------------------------------------------------
329 -- Loading fixity decls
330 -----------------------------------------------------
332 loadFixDecls mod decls
333 = mapRn (loadFixDecl mod_name) decls `thenRn` \ to_add ->
334 returnRn (mkNameEnv to_add)
336 mod_name = moduleName mod
338 loadFixDecl mod_name sig@(FixitySig rdr_name fixity loc)
339 = newGlobalName mod_name (rdrNameOcc rdr_name) `thenRn` \ name ->
340 returnRn (name, fixity)
343 -----------------------------------------------------
344 -- Loading instance decls
345 -----------------------------------------------------
347 loadInstDecls :: Module
351 loadInstDecls mod (insts, n_slurped) decls
353 foldlRn (loadInstDecl mod) insts decls `thenRn` \ insts' ->
354 returnRn (insts', n_slurped)
357 loadInstDecl mod insts decl@(InstDecl inst_ty _ _ _ _)
358 = -- Find out what type constructors and classes are "gates" for the
359 -- instance declaration. If all these "gates" are slurped in then
360 -- we should slurp the instance decl too.
362 -- We *don't* want to count names in the context part as gates, though.
364 -- instance Foo a => Baz (T a) where ...
366 -- Here the gates are Baz and T, but *not* Foo.
368 -- HOWEVER: functional dependencies make things more complicated
369 -- class C a b | a->b where ...
370 -- instance C Foo Baz where ...
371 -- Here, the gates are really only C and Foo, *not* Baz.
372 -- That is, if C and Foo are visible, even if Baz isn't, we must
375 -- Rather than take fundeps into account "properly", we just slurp
376 -- if C is visible and *any one* of the Names in the types
377 -- This is a slightly brutal approximation, but most instance decls
378 -- are regular H98 ones and it's perfect for them.
380 -- NOTICE that we rename the type before extracting its free
381 -- variables. The free-variable finder for a renamed HsType
382 -- does the Right Thing for built-in syntax like [] and (,).
384 rnHsType (text "In an interface instance decl") inst_ty
385 ) `thenRn` \ inst_ty' ->
387 (tvs,(cls,tys)) = getHsInstHead inst_ty'
388 free_tcs = nameSetToList (extractHsTyNames_s tys) `minusList` hsTyVarNames tvs
390 gate_fn vis_fn = vis_fn cls && (null free_tcs || any vis_fn free_tcs)
391 -- Here is the implementation of HOWEVER above
392 -- (Note that we do let the inst decl in if it mentions
393 -- no tycons at all. Hence the null free_ty_names.)
395 returnRn ((gate_fn, (mod, decl)) `consBag` insts)
399 -----------------------------------------------------
401 -----------------------------------------------------
403 loadRules :: Module -> IfaceRules
404 -> (Version, [RdrNameRuleDecl])
405 -> RnM d (Version, IfaceRules)
406 loadRules mod (rule_bag, n_slurped) (version, rules)
407 | null rules || opt_IgnoreIfacePragmas
408 = returnRn (version, (rule_bag, n_slurped))
411 mapRn (loadRule mod) rules `thenRn` \ new_rules ->
412 returnRn (version, (rule_bag `unionBags` listToBag new_rules, n_slurped))
414 loadRule :: Module -> RdrNameRuleDecl -> RnM d (GatedDecl RdrNameRuleDecl)
415 -- "Gate" the rule simply by whether the rule variable is
416 -- needed. We can refine this later.
417 loadRule mod decl@(IfaceRule _ _ _ var _ _ src_loc)
418 = lookupIfaceName var `thenRn` \ var_name ->
419 returnRn (\vis_fn -> vis_fn var_name, (mod, decl))
422 -----------------------------------------------------
423 -- Loading Deprecations
424 -----------------------------------------------------
426 loadDeprecs :: Module -> IfaceDeprecs -> RnM d Deprecations
427 loadDeprecs m Nothing = returnRn NoDeprecs
428 loadDeprecs m (Just (Left txt)) = returnRn (DeprecAll txt)
429 loadDeprecs m (Just (Right prs)) = setModuleRn m $
430 foldlRn loadDeprec emptyNameEnv prs `thenRn` \ env ->
431 returnRn (DeprecSome env)
432 loadDeprec deprec_env (n, txt)
433 = lookupIfaceName n `thenRn` \ name ->
434 traceRn (text "Loaded deprecation(s) for" <+> ppr name <> colon <+> ppr txt) `thenRn_`
435 returnRn (extendNameEnv deprec_env name (name,txt))
439 %*********************************************************
441 \subsection{Getting binders out of a declaration}
443 %*********************************************************
445 @getDeclBinders@ returns the names for a @RdrNameHsDecl@.
446 It's used for both source code (from @availsFromDecl@) and interface files
449 It doesn't deal with source-code specific things: @ValD@, @DefD@. They
450 are handled by the sourc-code specific stuff in @RnNames@.
452 *** See "THE NAMING STORY" in HsDecls ****
459 -> RnM d (AvailInfo, [Name]) -- The [Name] are the system names
462 getTyClDeclBinders mod (IfaceSig {tcdName = var, tcdLoc = src_loc})
463 = newTopBinder mod var src_loc `thenRn` \ var_name ->
464 returnRn (Avail var_name, [])
466 getTyClDeclBinders mod tycl_decl
467 = new_top_bndrs mod (tyClDeclNames tycl_decl) `thenRn` \ names@(main_name:_) ->
468 new_top_bndrs mod (tyClDeclSysNames tycl_decl) `thenRn` \ sys_names ->
469 returnRn (AvailTC main_name names, sys_names)
472 new_top_bndrs mod names_w_locs
473 = sequenceRn [newTopBinder mod name loc | (name,loc) <- names_w_locs]
477 %*********************************************************
479 \subsection{Reading an interface file}
481 %*********************************************************
484 findAndReadIface :: SDoc -> ModuleName
485 -> IsBootInterface -- True <=> Look for a .hi-boot file
486 -- False <=> Look for .hi file
487 -> RnM d (Either Message (Module, ParsedIface))
488 -- Nothing <=> file not found, or unreadable, or illegible
489 -- Just x <=> successfully found and parsed
491 findAndReadIface doc_str mod_name hi_boot_file
492 = traceRn trace_msg `thenRn_`
494 -- In interactive or --make mode, we are *not allowed* to demand-load
495 -- a home package .hi file. So don't even look for them.
496 -- This helps in the case where you are sitting in eg. ghc/lib/std
497 -- and start up GHCi - it won't complain that all the modules it tries
498 -- to load are found in the home location.
499 ioToRnM_no_fail (readIORef v_GhcMode) `thenRn` \ mode ->
500 let home_allowed = hi_boot_file ||
501 mode `notElem` [ DoInteractive, DoMake ]
504 ioToRnM (if home_allowed
505 then findModule mod_name
506 else findPackageModule mod_name) `thenRn` \ maybe_found ->
510 Right (Just (wanted_mod,locn))
511 -> mkHiPath hi_boot_file locn `thenRn` \ file ->
512 readIface file `thenRn` \ read_result ->
514 Left bad -> returnRn (Left bad)
516 -> let read_mod = pi_mod iface
517 in -- check that the module names agree
519 (wanted_mod == read_mod)
520 (hiModuleNameMismatchWarn wanted_mod read_mod)
522 -- check that the package names agree
524 (modulePackage wanted_mod == modulePackage read_mod)
525 (packageNameMismatchWarn wanted_mod read_mod)
527 returnRn (Right (wanted_mod, iface))
529 other -> traceRn (ptext SLIT("...not found")) `thenRn_`
530 returnRn (Left (noIfaceErr mod_name hi_boot_file))
533 trace_msg = sep [hsep [ptext SLIT("Reading"),
534 if hi_boot_file then ptext SLIT("[boot]") else empty,
535 ptext SLIT("interface for"),
536 ppr mod_name <> semi],
537 nest 4 (ptext SLIT("reason:") <+> doc_str)]
539 mkHiPath hi_boot_file locn
541 ioToRnM_no_fail (doesFileExist hi_boot_ver_path) `thenRn` \ b ->
542 if b then returnRn hi_boot_ver_path
543 else returnRn hi_boot_path
544 | otherwise = returnRn hi_path
545 where hi_path = ml_hi_file locn
546 (hi_base, _hi_suf) = splitFilename hi_path
547 hi_boot_path = hi_base ++ ".hi-boot"
548 hi_boot_ver_path = hi_base ++ ".hi-boot-" ++ cHscIfaceFileVersion
551 @readIface@ tries just the one file.
554 readIface :: String -> RnM d (Either Message ParsedIface)
555 -- Nothing <=> file not found, or unreadable, or illegible
556 -- Just x <=> successfully found and parsed
558 = --ioToRnM (putStrLn ("reading iface " ++ file_path)) `thenRn_`
559 traceRn (ptext SLIT("readIFace") <+> text file_path) `thenRn_`
561 ioToRnM (hGetStringBuffer False file_path) `thenRn` \ read_result ->
562 case read_result of {
563 Left io_error -> bale_out (text (show io_error)) ;
566 case parseIface contents init_parser_state of
567 POk _ iface -> returnRn (Right iface)
568 PFailed err -> bale_out err
571 init_parser_state = PState{ bol = 0#, atbol = 1#,
574 loc = mkSrcLoc (mkFastString file_path) 1 }
576 bale_out err = returnRn (Left (badIfaceFile file_path err))
579 %*********************************************************
581 \subsection{Looking up fixities}
583 %*********************************************************
585 @lookupFixityRn@ has to be in RnIfaces (or RnHiFiles), instead of
586 its obvious home in RnEnv, because it calls @loadHomeInterface@.
588 lookupFixity is a bit strange.
590 * Nested local fixity decls are put in the local fixity env, which we
591 find with getFixtyEnv
593 * Imported fixities are found in the HIT or PIT
595 * Top-level fixity decls in this module may be for Names that are
596 either Global (constructors, class operations)
597 or Local/Exported (everything else)
598 (See notes with RnNames.getLocalDeclBinders for why we have this split.)
599 We put them all in the local fixity environment
602 lookupFixityRn :: Name -> RnMS Fixity
604 = getModuleRn `thenRn` \ this_mod ->
605 if nameIsLocalOrFrom this_mod name
606 then -- It's defined in this module
607 getFixityEnv `thenRn` \ local_fix_env ->
608 returnRn (lookupLocalFixity local_fix_env name)
610 else -- It's imported
611 -- For imported names, we have to get their fixities by doing a
612 -- loadHomeInterface, and consulting the Ifaces that comes back
613 -- from that, because the interface file for the Name might not
614 -- have been loaded yet. Why not? Suppose you import module A,
615 -- which exports a function 'f', which is defined in module B.
616 -- Then B isn't loaded right away (after all, it's possible that
617 -- nothing from B will be used). When we come across a use of
618 -- 'f', we need to know its fixity, and it's then, and only
619 -- then, that we load B.hi. That is what's happening here.
620 loadHomeInterface doc name `thenRn` \ iface ->
621 returnRn (lookupNameEnv (mi_fixities iface) name `orElse` defaultFixity)
623 doc = ptext SLIT("Checking fixity for") <+> ppr name
627 %*********************************************************
631 %*********************************************************
634 noIfaceErr mod_name boot_file
635 = ptext SLIT("Could not find interface file for") <+> quotes (ppr mod_name)
636 -- We used to print the search path, but we can't do that
637 -- now, because it's hidden inside the finder.
638 -- Maybe the finder should expose more functions.
640 badIfaceFile file err
641 = vcat [ptext SLIT("Bad interface file:") <+> text file,
644 hiModuleNameMismatchWarn :: Module -> Module -> Message
645 hiModuleNameMismatchWarn requested_mod read_mod =
646 hsep [ ptext SLIT("Something is amiss; requested module name")
647 , ppr (moduleName requested_mod)
648 , ptext SLIT("differs from name found in the interface file")
652 packageNameMismatchWarn :: Module -> Module -> Message
653 packageNameMismatchWarn requested_mod read_mod =
654 fsep [ ptext SLIT("Module"), quotes (ppr requested_mod),
655 ptext SLIT("is located in package"),
656 quotes (ptext (modulePackage requested_mod)),
657 ptext SLIT("but its interface file claims it is part of package"),
658 quotes (ptext (modulePackage read_mod))
661 warnRedundantSourceImport mod_name
662 = ptext SLIT("Unnecessary {- SOURCE -} in the import of module")
663 <+> quotes (ppr mod_name)
666 = ptext SLIT("Importing my own interface: module") <+> ppr mod