When NLL is enabled in Rust 2015, this part of the edition guide should get updated: https://github.com/rust-lang-nursery/edition-guide/blame/5f3cc2a5618700efcde3bc00799744f21fa9ad2e/src/rust-2018/edition-changes.md#L6 I think this is the issue for NLL in 2015? https://github.com/rust-lang/rust/issues/57895 This is the full NLL tracking issue: https://github.com/rust-lang/rust/issues/43234