diff --git a/object.c b/object.c
index 5fa5322811..86a852c588 100644
--- a/object.c
+++ b/object.c
@@ -1686,7 +1686,8 @@ rb_false(VALUE obj)
 static VALUE
 rb_obj_match(VALUE obj1, VALUE obj2)
 {
-    rb_warning("Object#=~ is deprecated; it always returns nil");
+    rb_warning("deprecated Object#=~ is called on %"PRIsVALUE
+               "; it always returns nil", rb_obj_class(obj1));
     return Qnil;
 }