From 3bd2c56dae7dd8e319f563038f8ab8fa08db86cf Mon Sep 17 00:00:00 2001
From: "Yukihiro \"Matz\" Matsumoto" <matz@ruby.or.jp>
Date: Tue, 13 Dec 2022 10:49:14 +0900
Subject: [PATCH] vm.c (check_target_class): raise error if target_class is
 NULL

It fixes a bug that instance_eval for immediate objects defines methods
in Object, instead of raising error.

```ruby
1.instance_eval do
  def foo
    p :foo
  end
end
```
---
 src/vm.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/vm.c b/src/vm.c
index 6f6b9b001..b9ff95e5d 100644
--- a/src/vm.c
+++ b/src/vm.c
@@ -1290,7 +1290,7 @@ check_target_class(mrb_state *mrb)
 {
   struct RClass *target = CI_TARGET_CLASS(mrb->c->ci);
   if (!target) {
-    return mrb->object_class;
+    mrb_raise(mrb, E_TYPE_ERROR, "no class/module to add method");
   }
   return target;
 }