Broken dom_id

In the docs for dom_id, this is given as an example…

dom_id(Post.new(:id => 45)) # => “post_45”

This doesn’t work and I don’t see how it’s supposed to work. :id is a
protected attribute, meaning it will be nil.

The example above should always return “new_post”, not “post_45”.

Am I missing something here or is this just some bad documentation that
got in to Rails? I don’t even see this as an example in the test cases.

Thanks,
Andrew