vm_method.c: should not modify frozen objects

* vm_method.c (rb_method_entry_make, remove_method): ditto.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@47551 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 9 insertions, 0 deletions

diff --git a/test/ruby/test_class.rb b/test/ruby/test_class.rb
index 963c497d2f..9a4cdb0f58 100644
--- a/test/ruby/test_class.rb
+++ b/test/ruby/test_class.rb
@@ -384,4 +384,13 @@ class TestClass < Test::Unit::TestCase
       Class.new.freeze.clone.to_s
     }
   end
+
+  def test_singleton_class_of_frozen_object
+    obj = Object.new
+    c = obj.singleton_class
+    obj.freeze
+    assert_raise(RuntimeError, /frozen object/) {
+      c.class_eval {def f; end}
+    }
+  end
 end