From d73de65b602088d2eec20ec524a38c3f577d9b05 Mon Sep 17 00:00:00 2001
From: simonpj <unknown>
Date: Wed, 9 Oct 2002 15:16:53 +0000
Subject: [PATCH] [project @ 2002-10-09 15:16:53 by simonpj] Dont complain
 about unused things bound by deriving clause

---
 ghc/compiler/rename/RnNames.lhs |   12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/ghc/compiler/rename/RnNames.lhs b/ghc/compiler/rename/RnNames.lhs
index 3e440e9..f1c7992 100644
--- a/ghc/compiler/rename/RnNames.lhs
+++ b/ghc/compiler/rename/RnNames.lhs
@@ -29,7 +29,7 @@ import Module		( Module, ModuleName, moduleName,
 			  moduleNameUserString, 
 			  unitModuleEnvByName, lookupModuleEnvByName,
 			  moduleEnvElts )
-import Name		( Name, nameSrcLoc, nameOccName, nameModule )
+import Name		( Name, nameSrcLoc, nameOccName, nameModule, isExternalName )
 import NameSet
 import NameEnv
 import OccName		( OccName, dataName, isTcOcc )
@@ -615,9 +615,15 @@ reportUnusedNames gbl_env used_names
     (defined_and_used, defined_but_not_used) = partition used defined_names
     used gre = gre_name gre `elemNameSet` really_used_names
     
-    -- Filter out the ones only defined implicitly
+    -- Filter out the ones that are 
+    --  (a) defined in this module, and
+    --	(b) not defined by a 'deriving' clause 
+    -- The latter have an Internal Name, so we can filter them out easily
     bad_locals :: [GlobalRdrElt]
-    bad_locals = filter isLocalGRE defined_but_not_used
+    bad_locals = filter is_bad defined_but_not_used
+
+    is_bad :: GlobalRdrElt -> Bool
+    is_bad gre = isLocalGRE gre && isExternalName (gre_name gre)
     
     bad_imports :: [GlobalRdrElt]
     bad_imports = filter bad_imp defined_but_not_used
-- 
1.7.10.4