RustWeek Interview: Aapo Alasuutari

At RustWeek 2026, the Rust Project Content Team talks with Aapo Alasuutari, maintainer of the Nova JavaScript engine and driver of the reborrow traits language experiment. Aapo shares how he got into Rust: starting as a TypeScript developer, contributing to Deno to get FFI support he needed, and eventually maintaining a JavaScript engine of his own. Topics include: - Doing FFI from JavaScript into C++ with no C API in between, and what that taught him - Contributing to Deno (Rust) versus V8 (C++), including work deep in V8's optimizing compiler - Reborrow traits: giving types such as Pinᐸ&mut Tᐳ and other user-defined wrappers the same temporary reborrowing behavior built into exclusive references - How the language experiment process works: proposing a project goal, working with Tyler Mandry on the language design and Ding Xiang Fei on the compiler implementation - Setbacks along the way, and why unifying the new reborrowing with built-in exclusive reference reborrowing may eventually mean rewriting a large part of the compiler - How to help: the well-formedness checks for reborrow traits need work, and there are small, approachable tasks to pick up Aapo's RustWeek 2026 talk, "Can I borrow that? (Reborrow traits)": https://www.youtube.com/watch?v=2GE0GL0ith4 Links and resources: - Aapo on GitHub: https://github.com/aapoalas - Nova JavaScript engine: https://github.com/trynova/nova - Deno: https://github.com/denoland/deno - V8: https://v8.dev/ - RustWeek 2026: https://2026.rustweek.org/ - Reborrow traits project goal: https://rust-lang.github.io/rust-project-goals/2026/reborrow-traits.html - Project goals update covering reborrow traits progress: https://blog.rust-lang.org/2026/05/18/project-goals-2026-04/ - Tyler Mandry: https://github.com/tmandry - Ding Xiang Fei: https://github.com/dingxiangfei2009 - Aapo's FOSDEM 2025 talk on reborrowing and a safepoint garbage collector: https://archive.fosdem.org/2025/schedule/event/fosdem-2025-4394-abusing-reborrowing-for-fun-profit-and-a-safepoint-garbage-collector/ Interested in contributing to Rust? New contributors are always welcome. Find a small task, try to fix it, and the community will help you learn along the way. Interview conducted by Pete LeVasseur on behalf of the Rust Project Content Team. Find Pete at: - https://github.com/PLeVasseur/ - https://bsky.app/profile/petelevasseur.com