I don't believe this is correct. There was a plan to do that at some point, but it was pulled back from for backwards compat reasons. You can opt-in to string

I don't believe this is correct. There was a plan to do that at some point, but it was pulled back from for backwards compat reasons. You can opt-in to string literals being frozen by default on a per-source-file basis with a magic pragma comment, and this has existed for several ruby 2.x versions and is unchanged in the released ruby 3.0.