Provenance(..), pprNameProvenance,
Parent(..),
ImportSpec(..), ImpDeclSpec(..), ImpItemSpec(..),
- importSpecLoc, importSpecModule
+ importSpecLoc, importSpecModule, isExplicitItem
) where
#include "HsVersions.h"
importSpecModule :: ImportSpec -> ModuleName
importSpecModule is = is_mod (is_decl is)
+isExplicitItem :: ImpItemSpec -> Bool
+isExplicitItem ImpAll = False
+isExplicitItem (ImpSome {is_explicit = exp}) = exp
+
-- Note [Comparing provenance]
-- Comparison of provenance is just used for grouping
-- error messages (in RnEnv.warnUnusedBinds)
-------------------------
-- Helpers
warnUnusedGREs gres
- = warnUnusedBinds [(n,Just p) | GRE {gre_name = n, gre_prov = p} <- gres]
+ = warnUnusedBinds [(n,p) | GRE {gre_name = n, gre_prov = p} <- gres]
warnUnusedLocals names
- = warnUnusedBinds [(n,Nothing) | n<-names]
+ = warnUnusedBinds [(n,LocalDef) | n<-names]
-warnUnusedBinds :: [(Name,Maybe Provenance)] -> RnM ()
+warnUnusedBinds :: [(Name,Provenance)] -> RnM ()
warnUnusedBinds names = mappM_ warnUnusedName (filter reportable names)
where reportable (name,_)
| isWiredInName name = False -- Don't report unused wired-in names
-------------------------
-warnUnusedName :: (Name, Maybe Provenance) -> RnM ()
-warnUnusedName (name, prov)
- = addWarnAt loc $
+warnUnusedName :: (Name, Provenance) -> RnM ()
+warnUnusedName (name, LocalDef)
+ = addUnusedWarning name (srcLocSpan (nameSrcLoc name))
+ (ptext SLIT("Defined but not used"))
+
+warnUnusedName (name, Imported is)
+ = mapM_ warn is
+ where
+ warn spec = addUnusedWarning name span msg
+ where
+ span = importSpecLoc spec
+ pp_mod = quotes (ppr (importSpecModule spec))
+ msg = ptext SLIT("Imported from") <+> pp_mod <+> ptext SLIT("but not used")
+
+addUnusedWarning name span msg
+ = addWarnAt span $
sep [msg <> colon,
nest 2 $ pprNonVarNameSpace (occNameSpace (nameOccName name))
<+> quotes (ppr name)]
- -- TODO should be a proper span
- where
- (loc,msg) = case prov of
- Just (Imported is)
- -> (importSpecLoc imp_spec, imp_from (importSpecModule imp_spec))
- where
- imp_spec = head is
- other -> (srcLocSpan (nameSrcLoc name), unused_msg)
-
- unused_msg = text "Defined but not used"
- imp_from mod = text "Imported from" <+> quotes (ppr mod) <+> text "but not used"
\end{code}
\begin{code}
is_unused_local :: GlobalRdrElt -> Bool
is_unused_local gre = isLocalGRE gre && isExternalName (gre_name gre)
- unused_imports :: [GlobalRdrElt]
- unused_imports = filter unused_imp defined_but_not_used
- unused_imp (GRE {gre_prov = Imported imp_specs})
- = not (all (module_unused . importSpecModule) imp_specs)
- && or [exp | ImpSpec { is_item = ImpSome { is_explicit = exp } } <- imp_specs]
- -- Don't complain about unused imports if we've already said the
- -- entire import is unused
- unused_imp other = False
+ unused_imports :: [GlobalRdrElt]
+ unused_imports = mapCatMaybes unused_imp defined_but_not_used
+ unused_imp :: GlobalRdrElt -> Maybe GlobalRdrElt -- Result has trimmed Imported provenances
+ unused_imp gre@(GRE {gre_prov = LocalDef}) = Nothing
+ unused_imp gre@(GRE {gre_prov = Imported imp_specs})
+ | null trimmed_specs = Nothing
+ | otherwise = Just (gre {gre_prov = Imported trimmed_specs})
+ where
+ trimmed_specs = filter report_if_unused imp_specs
-- To figure out the minimal set of imports, start with the things
-- that are in scope (i.e. in gbl_env). Then just combine them
--
-- BUG WARNING: does not deal correctly with multiple imports of the same module
-- becuase direct_import_mods has only one entry per module
+ unused_imp_mods :: [(ModuleName, SrcSpan)]
unused_imp_mods = [(mod_name,loc) | (mod,no_imp,loc) <- direct_import_mods,
let mod_name = moduleName mod,
not (mod_name `elemFM` minimal_imports1),
module_unused :: ModuleName -> Bool
module_unused mod = any (((==) mod) . fst) unused_imp_mods
+ report_if_unused :: ImportSpec -> Bool
+ -- Do we want to report this as an unused import?
+ report_if_unused (ImpSpec {is_decl = d, is_item = i})
+ = not (module_unused (is_mod d)) -- Not if we've already said entire import is unused
+ && isExplicitItem i -- Only if the import was explicit
+
---------------------
warnDuplicateImports :: [GlobalRdrElt] -> RnM ()
-- Given the GREs for names that are used, figure out which imports