) where
+#include "HsVersions.h"
+
import Module
import HscTypes
import Packages
import PrelNames ( gHC_PRIM )
import DynFlags
import Outputable
-import LazyUniqFM
-import Maybes ( expectJust )
+import UniqFM
+import Maybes ( expectJust )
import Exception ( evaluate )
import Distribution.Text
import Distribution.Package hiding (PackageId)
-import Data.IORef ( IORef, writeIORef, readIORef, atomicModifyIORef )
+import Data.IORef ( IORef, writeIORef, readIORef, atomicModifyIORef )
import System.Directory
import System.FilePath
import Control.Monad
-import System.Time ( ClockTime )
+import System.Time ( ClockTime )
+import Data.List ( partition )
-type FileExt = String -- Filename extension
-type BaseName = String -- Basename of file
+type FileExt = String -- Filename extension
+type BaseName = String -- Basename of file
-- -----------------------------------------------------------------------------
-- The Finder
writeIORef fc_ref emptyUFM
flushModLocationCache this_pkg mlc_ref
where
- this_pkg = thisPackage (hsc_dflags hsc_env)
- fc_ref = hsc_FC hsc_env
- mlc_ref = hsc_MLC hsc_env
+ this_pkg = thisPackage (hsc_dflags hsc_env)
+ fc_ref = hsc_FC hsc_env
+ mlc_ref = hsc_MLC hsc_env
flushModLocationCache :: PackageId -> IORef ModLocationCache -> IO ()
flushModLocationCache this_pkg ref = do
_ <- evaluate =<< readIORef ref
return ()
where is_ext mod _ | modulePackageId mod /= this_pkg = True
- | otherwise = False
+ | otherwise = False
addToFinderCache :: IORef FinderCache -> ModuleName -> FindResult -> IO ()
addToFinderCache ref key val =
atomicModifyIORef ref $ \c -> (delModuleEnv c key, ())
lookupFinderCache :: IORef FinderCache -> ModuleName -> IO (Maybe FindResult)
-lookupFinderCache ref key = do
+lookupFinderCache ref key = do
c <- readIORef ref
return $! lookupUFM c key
findImportedModule :: HscEnv -> ModuleName -> Maybe FastString -> IO FindResult
findImportedModule hsc_env mod_name mb_pkg =
case mb_pkg of
- Nothing -> unqual_import
- Just pkg | pkg == fsLit "this" -> home_import -- "this" is special
- | otherwise -> pkg_import
+ Nothing -> unqual_import
+ Just pkg | pkg == fsLit "this" -> home_import -- "this" is special
+ | otherwise -> pkg_import
where
home_import = findHomeModule hsc_env mod_name
pkg_import = findExposedPackageModule hsc_env mod_name mb_pkg
- unqual_import = home_import
- `orIfNotFound`
- findExposedPackageModule hsc_env mod_name Nothing
+ unqual_import = home_import
+ `orIfNotFound`
+ findExposedPackageModule hsc_env mod_name Nothing
-- | Locate a specific 'Module'. The purpose of this function is to
-- create a 'ModLocation' for a given 'Module', that is to find out
-- where the files associated with this module live. It is used when
--- reading the interface for a module mentioned by another interface,
+-- reading the interface for a module mentioned by another interface,
-- for example (a "system import").
findExactModule :: HscEnv -> Module -> IO FindResult
findExactModule hsc_env mod =
- let dflags = hsc_dflags hsc_env in
- if modulePackageId mod == thisPackage dflags
- then findHomeModule hsc_env (moduleName mod)
- else findPackageModule hsc_env mod
+ let dflags = hsc_dflags hsc_env
+ in if modulePackageId mod == thisPackage dflags
+ then findHomeModule hsc_env (moduleName mod)
+ else findPackageModule hsc_env mod
-- -----------------------------------------------------------------------------
-- Helpers
orIfNotFound :: IO FindResult -> IO FindResult -> IO FindResult
-this `orIfNotFound` or_this = do
+orIfNotFound this or_this = do
res <- this
case res of
- NotFound places1 _mb_pkg1 mod_hiddens1 pkg_hiddens1 -> do
- res2 <- or_this
- case res2 of
- NotFound places2 mb_pkg2 mod_hiddens2 pkg_hiddens2 ->
- return (NotFound (places1 ++ places2)
- mb_pkg2 -- snd arg is the package search
- (mod_hiddens1 ++ mod_hiddens2)
- (pkg_hiddens1 ++ pkg_hiddens2))
- _other -> return res2
+ NotFound { fr_paths = paths1, fr_mods_hidden = mh1
+ , fr_pkgs_hidden = ph1, fr_suggestions = s1 }
+ -> do res2 <- or_this
+ case res2 of
+ NotFound { fr_paths = paths2, fr_pkg = mb_pkg2, fr_mods_hidden = mh2
+ , fr_pkgs_hidden = ph2, fr_suggestions = s2 }
+ -> return (NotFound { fr_paths = paths1 ++ paths2
+ , fr_pkg = mb_pkg2 -- snd arg is the package search
+ , fr_mods_hidden = mh1 ++ mh2
+ , fr_pkgs_hidden = ph1 ++ ph2
+ , fr_suggestions = s1 ++ s2 })
+ _other -> return res2
_other -> return res
homeSearchCache :: HscEnv -> ModuleName -> IO FindResult -> IO FindResult
homeSearchCache hsc_env mod_name do_this = do
m <- lookupFinderCache (hsc_FC hsc_env) mod_name
- case m of
+ case m of
Just result -> return result
Nothing -> do
- result <- do_this
- addToFinderCache (hsc_FC hsc_env) mod_name result
- case result of
- Found loc mod -> addToModLocationCache (hsc_MLC hsc_env) mod loc
- _other -> return ()
- return result
+ result <- do_this
+ addToFinderCache (hsc_FC hsc_env) mod_name result
+ case result of
+ Found loc mod -> addToModLocationCache (hsc_MLC hsc_env) mod loc
+ _other -> return ()
+ return result
findExposedPackageModule :: HscEnv -> ModuleName -> Maybe FastString
-> IO FindResult
findExposedPackageModule hsc_env mod_name mb_pkg
-- not found in any package:
- | null found_exposed = return (NotFound [] Nothing mod_hiddens pkg_hiddens)
- -- found in just one exposed package:
- | [(pkg_conf, _)] <- found_exposed
- = let pkgid = packageConfigId pkg_conf in
- findPackageModule_ hsc_env (mkModule pkgid mod_name) pkg_conf
- | otherwise
- = return (FoundMultiple (map (packageConfigId.fst) found_exposed))
- where
- dflags = hsc_dflags hsc_env
- found = lookupModuleInAllPackages dflags mod_name
-
- for_this_pkg = filter ((`matches` mb_pkg) . fst) found
-
- found_exposed = [ (pkg_conf,exposed_mod)
- | x@(pkg_conf,exposed_mod) <- for_this_pkg,
- is_exposed x ]
-
- is_exposed (pkg_conf,exposed_mod) = exposed pkg_conf && exposed_mod
-
- mod_hiddens = [ packageConfigId pkg_conf
- | (pkg_conf,False) <- found ]
-
- pkg_hiddens = [ packageConfigId pkg_conf
- | (pkg_conf,_) <- found, not (exposed pkg_conf) ]
-
- _pkg_conf `matches` Nothing = True
- pkg_conf `matches` Just pkg =
- case packageName pkg_conf of
- PackageName n -> pkg == mkFastString n
-
+ = case lookupModuleWithSuggestions (hsc_dflags hsc_env) mod_name of
+ Left suggest -> return (NotFound { fr_paths = [], fr_pkg = Nothing
+ , fr_pkgs_hidden = [], fr_mods_hidden = []
+ , fr_suggestions = suggest })
+ Right found
+ | null found_exposed -- Found, but with no exposed copies
+ -> return (NotFound { fr_paths = [], fr_pkg = Nothing
+ , fr_pkgs_hidden = pkg_hiddens, fr_mods_hidden = mod_hiddens
+ , fr_suggestions = [] })
+
+ | [(pkg_conf,_)] <- found_exposed -- Found uniquely
+ -> let pkgid = packageConfigId pkg_conf in
+ findPackageModule_ hsc_env (mkModule pkgid mod_name) pkg_conf
+
+ | otherwise -- Found in more than one place
+ -> return (FoundMultiple (map (packageConfigId.fst) found_exposed))
+ where
+ for_this_pkg = case mb_pkg of
+ Nothing -> found
+ Just p -> filter ((`matches` p) . fst) found
+ found_exposed = filter is_exposed for_this_pkg
+ is_exposed (pkg_conf,exposed_mod) = exposed pkg_conf && exposed_mod
+
+ mod_hiddens = [ packageConfigId pkg_conf
+ | (pkg_conf,False) <- found ]
+
+ pkg_hiddens = [ packageConfigId pkg_conf
+ | (pkg_conf,_) <- found, not (exposed pkg_conf) ]
+
+ pkg_conf `matches` pkg
+ = case packageName pkg_conf of
+ PackageName n -> pkg == mkFastString n
modLocationCache :: HscEnv -> Module -> IO FindResult -> IO FindResult
modLocationCache hsc_env mod do_this = do
Just loc -> return (Found loc mod)
Nothing -> do
result <- do_this
- case result of
- Found loc mod -> addToModLocationCache (hsc_MLC hsc_env) mod loc
- _other -> return ()
- return result
+ case result of
+ Found loc mod -> addToModLocationCache (hsc_MLC hsc_env) mod loc
+ _other -> return ()
+ return result
where
mlc = hsc_MLC hsc_env
removeFromModLocationCache (hsc_MLC hsc_env) (mkModule this_pkg mod)
-- -----------------------------------------------------------------------------
--- The internal workers
+-- The internal workers
-- | Search for a module in the home package only.
findHomeModule :: HscEnv -> ModuleName -> IO FindResult
hisuf = hiSuf dflags
mod = mkModule (thisPackage dflags) mod_name
- source_exts =
+ source_exts =
[ ("hs", mkHomeModLocationSearched dflags mod_name "hs")
, ("lhs", mkHomeModLocationSearched dflags mod_name "lhs")
]
-
- hi_exts = [ (hisuf, mkHiOnlyModLocation dflags hisuf)
- , (addBootSuffix hisuf, mkHiOnlyModLocation dflags hisuf)
- ]
-
- -- In compilation manager modes, we look for source files in the home
- -- package because we can compile these automatically. In one-shot
- -- compilation mode we look for .hi and .hi-boot files only.
+
+ hi_exts = [ (hisuf, mkHiOnlyModLocation dflags hisuf)
+ , (addBootSuffix hisuf, mkHiOnlyModLocation dflags hisuf)
+ ]
+
+ -- In compilation manager modes, we look for source files in the home
+ -- package because we can compile these automatically. In one-shot
+ -- compilation mode we look for .hi and .hi-boot files only.
exts | isOneShot (ghcMode dflags) = hi_exts
- | otherwise = source_exts
+ | otherwise = source_exts
in
-- special case for GHC.Prim; we won't find it in the filesystem.
-- This is important only when compiling the base package (where GHC.Prim
-- is a home module).
- if mod == gHC_PRIM
+ if mod == gHC_PRIM
then return (Found (error "GHC.Prim ModLocation") mod)
- else
-
- searchPathExts home_path mod exts
+ else searchPathExts home_path mod exts
-- | Search for a module in external packages only.
findPackageModule :: HscEnv -> Module -> IO FindResult
findPackageModule hsc_env mod = do
let
- dflags = hsc_dflags hsc_env
- pkg_id = modulePackageId mod
- pkg_map = pkgIdMap (pkgState dflags)
+ dflags = hsc_dflags hsc_env
+ pkg_id = modulePackageId mod
+ pkg_map = pkgIdMap (pkgState dflags)
--
case lookupPackage pkg_map pkg_id of
Nothing -> return (NoPackage pkg_id)
Just pkg_conf -> findPackageModule_ hsc_env mod pkg_conf
-
+
findPackageModule_ :: HscEnv -> Module -> PackageConfig -> IO FindResult
-findPackageModule_ hsc_env mod pkg_conf =
+findPackageModule_ hsc_env mod pkg_conf =
modLocationCache hsc_env mod $
-- special case for GHC.Prim; we won't find it in the filesystem.
- if mod == gHC_PRIM
+ if mod == gHC_PRIM
then return (Found (error "GHC.Prim ModLocation") mod)
- else
+ else
let
dflags = hsc_dflags hsc_env
tag = buildTag dflags
- -- hi-suffix for packages depends on the build tag.
+ -- hi-suffix for packages depends on the build tag.
package_hisuf | null tag = "hi"
- | otherwise = tag ++ "_hi"
+ | otherwise = tag ++ "_hi"
mk_hi_loc = mkHiOnlyModLocation dflags package_hisuf
-- General path searching
searchPathExts
- :: [FilePath] -- paths to search
- -> Module -- module name
+ :: [FilePath] -- paths to search
+ -> Module -- module name
-> [ (
- FileExt, -- suffix
- FilePath -> BaseName -> IO ModLocation -- action
+ FileExt, -- suffix
+ FilePath -> BaseName -> IO ModLocation -- action
)
- ]
+ ]
-> IO FindResult
-searchPathExts paths mod exts
+searchPathExts paths mod exts
= do result <- search to_search
{-
- hPutStrLn stderr (showSDoc $
- vcat [text "Search" <+> ppr mod <+> sep (map (text. fst) exts)
- , nest 2 (vcat (map text paths))
- , case result of
- Succeeded (loc, p) -> text "Found" <+> ppr loc
- Failed fs -> text "not found"])
--}
- return result
+ hPutStrLn stderr (showSDoc $
+ vcat [text "Search" <+> ppr mod <+> sep (map (text. fst) exts)
+ , nest 2 (vcat (map text paths))
+ , case result of
+ Succeeded (loc, p) -> text "Found" <+> ppr loc
+ Failed fs -> text "not found"])
+-}
+ return result
where
basename = moduleNameSlashes (moduleName mod)
to_search :: [(FilePath, IO ModLocation)]
to_search = [ (file, fn path basename)
- | path <- paths,
- (ext,fn) <- exts,
- let base | path == "." = basename
- | otherwise = path </> basename
- file = base <.> ext
- ]
-
- search [] = return (NotFound (map fst to_search) (Just (modulePackageId mod))
- [] [])
+ | path <- paths,
+ (ext,fn) <- exts,
+ let base | path == "." = basename
+ | otherwise = path </> basename
+ file = base <.> ext
+ ]
+
+ search [] = return (NotFound { fr_paths = map fst to_search
+ , fr_pkg = Just (modulePackageId mod)
+ , fr_mods_hidden = [], fr_pkgs_hidden = []
+ , fr_suggestions = [] })
+
search ((file, mk_result) : rest) = do
b <- doesFileExist file
- if b
- then do { loc <- mk_result; return (Found loc mod) }
- else search rest
+ if b
+ then do { loc <- mk_result; return (Found loc mod) }
+ else search rest
mkHomeModLocationSearched :: DynFlags -> ModuleName -> FileExt
- -> FilePath -> BaseName -> IO ModLocation
+ -> FilePath -> BaseName -> IO ModLocation
mkHomeModLocationSearched dflags mod suff path basename = do
mkHomeModLocation2 dflags mod (path </> basename) suff
-- (b) and (c): The filename of the source file, minus its extension
--
-- ext
--- The filename extension of the source file (usually "hs" or "lhs").
+-- The filename extension of the source file (usually "hs" or "lhs").
mkHomeModLocation :: DynFlags -> ModuleName -> FilePath -> IO ModLocation
mkHomeModLocation dflags mod src_filename = do
mkHomeModLocation2 dflags mod basename extension
mkHomeModLocation2 :: DynFlags
- -> ModuleName
- -> FilePath -- Of source module, without suffix
- -> String -- Suffix
- -> IO ModLocation
+ -> ModuleName
+ -> FilePath -- Of source module, without suffix
+ -> String -- Suffix
+ -> IO ModLocation
mkHomeModLocation2 dflags mod src_basename ext = do
let mod_basename = moduleNameSlashes mod
hi_fn <- mkHiPath dflags src_basename mod_basename
return (ModLocation{ ml_hs_file = Just (src_basename <.> ext),
- ml_hi_file = hi_fn,
- ml_obj_file = obj_fn })
+ ml_hi_file = hi_fn,
+ ml_obj_file = obj_fn })
mkHiOnlyModLocation :: DynFlags -> Suffix -> FilePath -> String
- -> IO ModLocation
+ -> IO ModLocation
mkHiOnlyModLocation dflags hisuf path basename
= do let full_basename = path </> basename
obj_fn <- mkObjPath dflags full_basename basename
return ModLocation{ ml_hs_file = Nothing,
- ml_hi_file = full_basename <.> hisuf,
- -- Remove the .hi-boot suffix from
- -- hi_file, if it had one. We always
- -- want the name of the real .hi file
- -- in the ml_hi_file field.
- ml_obj_file = obj_fn
+ ml_hi_file = full_basename <.> hisuf,
+ -- Remove the .hi-boot suffix from
+ -- hi_file, if it had one. We always
+ -- want the name of the real .hi file
+ -- in the ml_hi_file field.
+ ml_obj_file = obj_fn
}
-- | Constructs the filename of a .o file for a given source file.
-- Does /not/ check whether the .o file exists
mkObjPath
:: DynFlags
- -> FilePath -- the filename of the source file, minus the extension
- -> String -- the module name with dots replaced by slashes
+ -> FilePath -- the filename of the source file, minus the extension
+ -> String -- the module name with dots replaced by slashes
-> IO FilePath
mkObjPath dflags basename mod_basename
= do let
- odir = objectDir dflags
- osuf = objectSuf dflags
-
- obj_basename | Just dir <- odir = dir </> mod_basename
- | otherwise = basename
+ odir = objectDir dflags
+ osuf = objectSuf dflags
+
+ obj_basename | Just dir <- odir = dir </> mod_basename
+ | otherwise = basename
return (obj_basename <.> osuf)
-- Does /not/ check whether the .hi file exists
mkHiPath
:: DynFlags
- -> FilePath -- the filename of the source file, minus the extension
- -> String -- the module name with dots replaced by slashes
+ -> FilePath -- the filename of the source file, minus the extension
+ -> String -- the module name with dots replaced by slashes
-> IO FilePath
mkHiPath dflags basename mod_basename
= do let
- hidir = hiDir dflags
- hisuf = hiSuf dflags
+ hidir = hiDir dflags
+ hisuf = hiSuf dflags
- hi_basename | Just dir <- hidir = dir </> mod_basename
- | otherwise = basename
+ hi_basename | Just dir <- hidir = dir </> mod_basename
+ | otherwise = basename
return (hi_basename <.> hisuf)
:: DynFlags
-> ModuleName
-> ModLocation
- -> (FilePath,FilePath,FilePath)
+ -> FilePath
mkStubPaths dflags mod location
= let
stubdir = stubDir dflags
mod_basename = moduleNameSlashes mod
- src_basename = dropExtension $ expectJust "mkStubPaths"
+ src_basename = dropExtension $ expectJust "mkStubPaths"
(ml_hs_file location)
stub_basename0
| otherwise = src_basename
stub_basename = stub_basename0 ++ "_stub"
-
- obj = ml_obj_file location
- osuf = objectSuf dflags
- stub_obj_base = dropTail (length osuf + 1) obj ++ "_stub"
- -- NB. not takeFileName, see #3093
in
- (stub_basename <.> "c",
- stub_basename <.> "h",
- stub_obj_base <.> objectSuf dflags)
+ stub_basename <.> "h"
-- -----------------------------------------------------------------------------
--- findLinkable isn't related to the other stuff in here,
+-- findLinkable isn't related to the other stuff in here,
-- but there's no other obvious place for it
findObjectLinkableMaybe :: Module -> ModLocation -> IO (Maybe Linkable)
findObjectLinkableMaybe mod locn
= do let obj_fn = ml_obj_file locn
- maybe_obj_time <- modificationTimeIfExists obj_fn
- case maybe_obj_time of
- Nothing -> return Nothing
- Just obj_time -> liftM Just (findObjectLinkable mod obj_fn obj_time)
+ maybe_obj_time <- modificationTimeIfExists obj_fn
+ case maybe_obj_time of
+ Nothing -> return Nothing
+ Just obj_time -> liftM Just (findObjectLinkable mod obj_fn obj_time)
-- Make an object linkable when we know the object file exists, and we know
-- its modification time.
findObjectLinkable :: Module -> FilePath -> ClockTime -> IO Linkable
-findObjectLinkable mod obj_fn obj_time = do
- let stub_fn = (dropExtension obj_fn ++ "_stub") <.> "o"
- stub_exist <- doesFileExist stub_fn
- if stub_exist
- then return (LM obj_time mod [DotO obj_fn, DotO stub_fn])
- else return (LM obj_time mod [DotO obj_fn])
+findObjectLinkable mod obj_fn obj_time = return (LM obj_time mod [DotO obj_fn])
+ -- We used to look for _stub.o files here, but that was a bug (#706)
+ -- Now GHC merges the stub.o into the main .o (#3687)
-- -----------------------------------------------------------------------------
-- Error messages
cantFindErr _ multiple_found _ mod_name (FoundMultiple pkgs)
= hang (ptext multiple_found <+> quotes (ppr mod_name) <> colon) 2 (
sep [ptext (sLit "it was found in multiple packages:"),
- hsep (map (text.packageIdString) pkgs)]
+ hsep (map (text.packageIdString) pkgs)]
)
cantFindErr cannot_find _ dflags mod_name find_result
- = hang (ptext cannot_find <+> quotes (ppr mod_name) <> colon)
- 2 more_info
+ = ptext cannot_find <+> quotes (ppr mod_name)
+ $$ more_info
where
+ pkg_map :: PackageConfigMap
+ pkg_map = pkgIdMap (pkgState dflags)
+
more_info
= case find_result of
- NoPackage pkg
- -> ptext (sLit "no package matching") <+> quotes (ppr pkg) <+>
- ptext (sLit "was found")
+ NoPackage pkg
+ -> ptext (sLit "no package matching") <+> quotes (ppr pkg) <+>
+ ptext (sLit "was found")
+
+ NotFound { fr_paths = files, fr_pkg = mb_pkg
+ , fr_mods_hidden = mod_hiddens, fr_pkgs_hidden = pkg_hiddens
+ , fr_suggestions = suggest }
+ | Just pkg <- mb_pkg, pkg /= thisPackage dflags
+ -> not_found_in_package pkg files
- NotFound files mb_pkg mod_hiddens pkg_hiddens
- | Just pkg <- mb_pkg, pkg /= thisPackage dflags
- -> not_found_in_package pkg files
+ | not (null suggest)
+ -> pp_suggestions suggest $$ tried_these files
| null files && null mod_hiddens && null pkg_hiddens
- -> ptext (sLit "it is not a module in the current program, or in any known package.")
+ -> ptext (sLit "It is not a module in the current program, or in any known package.")
- | otherwise
- -> vcat (map pkg_hidden pkg_hiddens) $$
- vcat (map mod_hidden mod_hiddens) $$
+ | otherwise
+ -> vcat (map pkg_hidden pkg_hiddens) $$
+ vcat (map mod_hidden mod_hiddens) $$
tried_these files
- NotFoundInPackage pkg
- -> ptext (sLit "it is not in package") <+> quotes (ppr pkg)
-
- _ -> panic "cantFindErr"
+ _ -> panic "cantFindErr"
build_tag = buildTag dflags
tried_these files
| null files = empty
| verbosity dflags < 3 =
- ptext (sLit "Use -v to see a list of the files searched for.")
+ ptext (sLit "Use -v to see a list of the files searched for.")
| otherwise =
- hang (ptext (sLit "locations searched:")) 2 $ vcat (map text files)
-
+ hang (ptext (sLit "Locations searched:")) 2 $ vcat (map text files)
+
pkg_hidden pkg =
ptext (sLit "It is a member of the hidden package") <+> quotes (ppr pkg)
<> dot $$ cabal_pkg_hidden_hint pkg
mod_hidden pkg =
ptext (sLit "it is a hidden module in the package") <+> quotes (ppr pkg)
+
+ pp_suggestions :: [Module] -> SDoc
+ pp_suggestions sugs
+ | null sugs = empty
+ | otherwise = hang (ptext (sLit "Perhaps you meant"))
+ 2 (vcat [ vcat (map pp_exp exposed_sugs)
+ , vcat (map pp_hid hidden_sugs) ])
+ where
+ (exposed_sugs, hidden_sugs) = partition from_exposed_pkg sugs
+
+ from_exposed_pkg m = case lookupPackage pkg_map (modulePackageId m) of
+ Just pkg_config -> exposed pkg_config
+ Nothing -> WARN( True, ppr m ) -- Should not happen
+ False
+
+ pp_exp mod = ppr (moduleName mod)
+ <+> parens (ptext (sLit "from") <+> ppr (modulePackageId mod))
+ pp_hid mod = ppr (moduleName mod)
+ <+> parens (ptext (sLit "needs flag -package") <+> ppr (modulePackageId mod))
\end{code}