Improve handling of unused imports (test is mod75)

[ghc-hetmet.git] / compiler / rename / RnEnv.lhs

diff --git a/compiler/rename/RnEnv.lhs b/compiler/rename/RnEnv.lhs
index 16c1b0b..32806f0 100644 (file)
--- a/compiler/rename/RnEnv.lhs
+++ b/compiler/rename/RnEnv.lhs
@@ -775,12 +775,12 @@ warnUnusedMatches    names = ifOptM Opt_WarnUnusedMatches (warnUnusedLocals name
 -------------------------
 --     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
@@ -790,23 +790,25 @@ warnUnusedBinds names  = mappM_ warnUnusedName (filter reportable 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}