diff --git a/Source/cmTarget.cxx b/Source/cmTarget.cxx
index b6182abfd..cab7e7c98 100644
--- a/Source/cmTarget.cxx
+++ b/Source/cmTarget.cxx
@@ -1990,7 +1990,6 @@ static void processIncludeDirectories(cmTarget *tgt,
             {
             case cmPolicies::WARN:
               {
-              cmOStringStream w;
               e << (mf->GetPolicies()
                     ->GetPolicyWarning(cmPolicies::CMP0021)) << "\n";
               messageType = cmake::AUTHOR_WARNING;