The code the blog presents copied from the std, ironically it does include the line where the len is set to 0 with a in code comment (but the article fails to go into it and seems to not be quite aware of the issue, it's otherwise quite good).

Also:

- up to date explanation in the nomicon: https://doc.rust-lang.org/nightly/nomicon/leaking.html

- from 2015 when it was realized leak must be sound: https://faultlore.com/blah/everyone-poops/