Rubyのparser gemが3.4になってから互換性が無いです警告をずっと出し続けてきていて，しかしparser gem自体はもう古いからPrism使いなよ，って案内を出してきてる．

> The parser gem is only compatible with the syntax of Ruby 3.3 and lower. For Ruby 3.4 and later, please use the Prism::Translation::Parser instead.

https://github.com/whitequark/parser/tree/6c925331c843ee57205940c2223da0fab665dd66

どうしましょうかね…

---

以下実験メモ

警告メッセージ

```
warning: parser/current is loading parser/ruby34, which recognizes 3.4.0-dev-compliant syntax, but you are running 3.4.1.
Please see https://github.com/whitequark/parser#compatibility-with-ruby-mri.
```

再現方法

`Dockerfile`

```
FROM ruby:3.4.1
RUN gem install parser
CMD ["ruby", "-e", "require 'parser/current'"]
```

```sh
docker image build . -t parser341
docker container run --rm parser341
```