diff --git a/ChangeLog b/ChangeLog
index bf615e503c..47449e2bac 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Thu Aug  5 17:11:43 2010  Yukihiro Matsumoto  <matz@ruby-lang.org>
+
+	* parse.y (void_expr_gen): add 'possibly' to warning message.
+	  [ruby-core:31611]
+
 Thu Aug  5 16:57:20 2010  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* dir.c (glob_make_pattern): fold continuous PLAINs to get rid of
diff --git a/parse.y b/parse.y
index ba5213577a..d6322824cd 100644
--- a/parse.y
+++ b/parse.y
@@ -8537,7 +8537,7 @@ void_expr_gen(struct parser_params *parser, NODE *node)
 	int line = ruby_sourceline;
 
 	ruby_sourceline = nd_line(node);
-	rb_warnS("useless use of %s in void context", useless);
+	rb_warnS("possibly useless use of %s in void context", useless);
 	ruby_sourceline = line;
     }
 }