Issue #20912 has been updated by jhawthorn (John Hawthorn). Subject changed from Move warning when redefining object_id to __id__ to Add warning when redefining __id__ as well as object_id Okay, I will add the warning to `__id__` as well as `object_id` ---------------------------------------- Feature #20912: Add warning when redefining __id__ as well as object_id https://bugs.ruby-lang.org/issues/20912#change-110808 * Author: jhawthorn (John Hawthorn) * Status: Open ---------------------------------------- Currently if you create a class and redefine or remove either `object_id` or `__send__` it will issue a warning. There's no such warning on `__id__`. ``` ❯ ruby -we 'class << Object.new; def object_id = 1; end' -e:1: warning: redefining `object_id' may cause serious problems ❯ ruby -we 'class << Object.new; def __id__ = 1; end' ❯ ``` It makes sense that there's no warning on `send`, because we expect `__send__` to be the method reliably available. `__send__` is on `BasicObject`, `send` is only on `Kernel`. This seems a little inconsistent that `object_id` warns while `__id__` does not warn. `__id__` is the equivalent to `__send__` as it's also on `BasicObject`, where `object_id` is only on `Kernel`. This may be a more obvious problem in Ruby 3.4.0 as commit:cffd380390967d17899fde0a81f5151ae6ddd076 makes the warning print in more cases. I propose we change this warning to be emitted only when `__id__` is redefined and not when `object_id` is redefined: **Proposed behaviour:** ``` ❯ ruby -we 'class << Object.new; def object_id = 1; end' ❯ ruby -we 'class << Object.new; def __id__ = 1; end' -e:1: warning: redefining `__id__' may cause serious problems ❯ ``` -- https://bugs.ruby-lang.org/