... and it was by no means Rust's fault. Rust's slice.binary_search_by() used to have an implementation equivalent to upper_bound(), and it got improved recent

... and it was by no means Rust's fault. Rust's slice.binary_search_by() used to have an implementation equivalent to upper_bound(), and it got improved recently. The PR of the improvement: https://github.com/rust-lang/rust/pull/74024 https://github.com/rust-lang/rust/pull/74024 Polkadot's postmortem: https://polkadot.network/a-polkadot-postmortem-24-05-2021/ https://polkadot.network/a-polkadot-postmortem-24-05-2021/