Introduction

Lifetimes are one of Rust’s most distinctive feature. They are what makes the language so valuable in the systems programming domain, and it’s essential to master them to use Rust effectively. Unfortunately, they’re not very well explained topic: to have a really solid understanding of how lifetimes work you have to learn about them bit by bit from scattered blogs, rustlang GitHub issues, compiler source-code, and Zulip discussions – so this book is my attempt to cover everything in a single place.

We will start from the Basics chapter where we will explore how lifetime annotations affect the borrow checking, after finishing this chapter you should be able to annotate your code with a confidence and an understanding of what you’re doing. Then we will touch various topics that are nice to know about in certain situations and which are not as important as Basics so you can always revisit them when you need to.

The book was never finished

Originally, I planned to cover a broad list of lifetime-related topics but due to some unfortunate circumstances this project had to be freezed. If you find the information here valuable you can help resurrecting the book with your contributions

• Fix typos, improve wording, suggest improvements to existing chapters
• Contribute more examples and exercises
  • right now the lifetime subtyping chapter desperately needs a good intuitive example justifying the use of outlives relationship in function signatures
• Contribute misc chapters about:
  • Reborrowing and stacked borrows
  • Lifetime ellision rules, different rules for functions and closures, tricks that help to fix incorrectly ellided lifetimes
  • Late and early bounds and the use of for<'a>
  • When the use of lifetimes in trait definitions is justified
  • Polonius(intuitive model) and the future of borrowchk
  • Lifetimes in GATs
  • Binding lifetimes in unsafe code
  • …etc…