Commit 305b24aa authored by Simon Marlow's avatar Simon Marlow

Improvements to the "can't find module" error message (#2980)

If the module was found in multiple hidden packages, we list them all.

Could not find module `Data.Generics':
  it is a member of the hidden package `base-3.0.3.0'
  it is a member of the hidden package `syb'
  Use -v to see a list of the files searched for.
parent dc01512f
......@@ -149,10 +149,14 @@ orIfNotFound :: IO FindResult -> IO FindResult -> IO FindResult
this `orIfNotFound` or_this = do
res <- this
case res of
NotFound here _ -> do
NotFound places1 _mb_pkg1 mod_hiddens1 pkg_hiddens1 -> do
res2 <- or_this
case res2 of
NotFound or_here pkg -> return (NotFound (here ++ or_here) pkg)
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
_other -> return res
......@@ -174,30 +178,31 @@ findExposedPackageModule :: HscEnv -> ModuleName -> Maybe FastString
-> IO FindResult
findExposedPackageModule hsc_env mod_name mb_pkg
-- not found in any package:
| null found = return (NotFound [] Nothing)
| null found_exposed = return (NotFound [] Nothing mod_hiddens pkg_hiddens)
-- found in just one exposed package:
| [(pkg_conf, _)] <- found_exposed
= let pkgid = mkPackageId (package pkg_conf) in
findPackageModule_ hsc_env (mkModule pkgid mod_name) pkg_conf
-- not found in any exposed package, report how it was hidden:
| null found_exposed, ((pkg_conf, exposed_mod):_) <- found
= let pkgid = mkPackageId (package pkg_conf) in
if not (exposed_mod)
then return (ModuleHidden pkgid)
else return (PackageHidden pkgid)
| otherwise
= return (FoundMultiple (map (mkPackageId.package.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) <- found,
is_exposed x,
pkg_conf `matches` mb_pkg ]
| x@(pkg_conf,exposed_mod) <- for_this_pkg,
is_exposed x ]
is_exposed (pkg_conf,exposed_mod) = exposed pkg_conf && exposed_mod
mod_hiddens = [ mkPackageId (package pkg_conf)
| (pkg_conf,False) <- found ]
pkg_hiddens = [ mkPackageId (package pkg_conf)
| (pkg_conf,_) <- found, not (exposed pkg_conf) ]
_pkg_conf `matches` Nothing = True
pkg_conf `matches` Just pkg =
case packageName pkg_conf of
......@@ -298,24 +303,22 @@ findPackageModule_ hsc_env mod pkg_conf =
-- hi-suffix for packages depends on the build tag.
package_hisuf | null tag = "hi"
| otherwise = tag ++ "_hi"
hi_exts =
[ (package_hisuf, mkHiOnlyModLocation dflags package_hisuf) ]
source_exts =
[ ("hs", mkHiOnlyModLocation dflags package_hisuf)
, ("lhs", mkHiOnlyModLocation dflags package_hisuf)
]
-- mkdependHS needs to look for source files in packages too, so
-- that we can make dependencies between package before they have
-- been built.
exts
| MkDepend <- ghcMode dflags = hi_exts ++ source_exts
| otherwise = hi_exts
mk_hi_loc = mkHiOnlyModLocation dflags package_hisuf
import_dirs = importDirs pkg_conf
-- we never look for a .hi-boot file in an external package;
-- .hi-boot files only make sense for the home package.
in
searchPathExts (importDirs pkg_conf) mod exts
case import_dirs of
[one] | MkDepend <- ghcMode dflags -> do
-- there's only one place that this .hi file can be, so
-- don't bother looking for it.
let basename = moduleNameSlashes (moduleName mod)
loc <- mk_hi_loc one basename
return (Found loc mod)
_otherwise ->
searchPathExts import_dirs mod [(package_hisuf, mk_hi_loc)]
-- -----------------------------------------------------------------------------
-- General path searching
......@@ -354,7 +357,8 @@ searchPathExts paths mod exts
file = base <.> ext
]
search [] = return (NotFound (map fst to_search) (Just (modulePackageId mod)))
search [] = return (NotFound (map fst to_search) (Just (modulePackageId mod))
[] [])
search ((file, mk_result) : rest) = do
b <- doesFileExist file
if b
......@@ -555,29 +559,24 @@ cantFindErr cannot_find dflags mod_name find_result
where
more_info
= case find_result of
PackageHidden pkg
-> ptext (sLit "it is a member of package") <+> ppr pkg <> comma
<+> ptext (sLit "which is hidden")
ModuleHidden pkg
-> ptext (sLit "it is hidden") <+> parens (ptext (sLit "in package")
<+> ppr pkg)
NoPackage pkg
-> ptext (sLit "no package matching") <+> ppr pkg <+>
-> ptext (sLit "no package matching") <+> quotes (ppr pkg) <+>
ptext (sLit "was found")
NotFound files mb_pkg
| null files
-> ptext (sLit "it is not a module in the current program, or in any known package.")
NotFound files mb_pkg mod_hiddens pkg_hiddens
| Just pkg <- mb_pkg, pkg /= thisPackage dflags
-> not_found_in_package pkg 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.")
| otherwise
-> not_found files
-> vcat (map pkg_hidden pkg_hiddens) $$
vcat (map mod_hidden mod_hiddens) $$
tried_these files
NotFoundInPackage pkg
-> ptext (sLit "it is not in package") <+> ppr pkg
-> ptext (sLit "it is not in package") <+> quotes (ppr pkg)
_ -> panic "cantFindErr"
......@@ -590,18 +589,25 @@ cantFindErr cannot_find dflags mod_name find_result
else "\"" ++ build_tag ++ "\""
in
ptext (sLit "Perhaps you haven't installed the ") <> text build <>
ptext (sLit " libraries for package ") <> ppr pkg <> char '?' $$
not_found files
ptext (sLit " libraries for package ") <> quotes (ppr pkg) <> char '?' $$
tried_these files
| otherwise
= ptext (sLit "There are files missing in the ") <> ppr pkg <>
= ptext (sLit "There are files missing in the ") <> quotes (ppr pkg) <>
ptext (sLit " package,") $$
ptext (sLit "try running 'ghc-pkg check'.") $$
not_found files
not_found files
| verbosity dflags < 3
= ptext (sLit "Use -v to see a list of the files searched for.")
| otherwise
= hang (ptext (sLit "locations searched:")) 2 (vcat (map text files))
tried_these files
tried_these files
| null files = empty
| verbosity dflags < 3 =
ptext (sLit "Use -v to see a list of the files searched for.")
| otherwise =
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)
mod_hidden pkg =
ptext (sLit "it is a hidden module in the package") <+> quotes (ppr pkg)
\end{code}
......@@ -800,14 +800,12 @@ data FindResult
-- ^ The requested package was not found
| FoundMultiple [PackageId]
-- ^ _Error_: both in multiple packages
| PackageHidden PackageId
-- ^ For an explicit source import, the package containing the module is
-- not exposed.
| ModuleHidden PackageId
-- ^ For an explicit source import, the package containing the module is
-- exposed, but the module itself is hidden.
| NotFound [FilePath] (Maybe PackageId)
-- ^ The module was not found, the specified places were searched
| NotFound [FilePath] (Maybe PackageId) [PackageId] [PackageId]
-- ^ The module was not found, including either
-- * the specified places were searched
-- * the package that this module should have been in
-- * list of packages in which the module was hidden,
-- * list of hidden packages containing this module
| NotFoundInPackage PackageId
-- ^ The module was not found in this package
......
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