Undefined behavior on rust isn’t anything new, there’s even a section in the book about it. https://doc.rust-lang.org/beta/reference/behavior-considered-undefin

Undefined behavior on rust isn’t anything new, there’s even a section in the book about it. https://doc.rust-lang.org/beta/reference/behavior-considered-undefined.html https://doc.rust-lang.org/beta/reference/behavior-considered... The issue referenced happens in an unsafe code block, see this patch. https://github.com/crossbeam-rs/crossbeam/pull/533/commits/be327d581e8434a2ba41b74affc915f42d8abfcd https://github.com/crossbeam-rs/crossbeam/pull/533/commits/b... There is no promise that Rust protects programmers from making mistakes in code marked as unsafe.