Best Rust Interview Questions To Ask A Developer

If you’re tasked with hiring a Rust developer, then you’ve likely encountered the challenge of finding the right questions to ask during the interview process.

Rust, an open-source programming language released in 2015, is gaining popularity worldwide for its memory safety and concurrency benefits. As such, it’s critical you hire someone well-versed in this language to strengthen your team's skillset.

Now, let's deep-dive into the top 15 Rust interview questions you should ask the candidates.

1. How would you describe Rust and its major strengths?

This question helps you to assess the candidate's understanding of the Rust programming language and its benefits. This would include aspects such as its performance, safety, concurrency, and memory management features.

It also allows you to gauge whether the candidate is able to articulate complex concepts in a clear and concise manner.

2. Share how you’ve used Rust's memory safety feature in a project.

One of Rust's main selling points is its memory safety guarantees without needing a garbage collector.

The way a candidate answers this question can show their practical experience with Rust's unique features and provide insights into how they approach problem-solving and design decisions related to memory safety.

3. What are the different types of errors in Rust and how do you handle them?

Rust makes a clear distinction between recoverable and unrecoverable errors, which should be handled differently. Understanding this is key to writing reliable Rust code.

This question allows you to assess the candidate's understanding of these types of errors and their ability to write robust, error-resistant code.

4. Discuss your experience in concurrency. How does Rust manage it?

Concurrency is another strong point of Rust and it's built into the language in a way that minimizes common bugs related to thread safety.

A candidate's answer to this question will show their understanding of Rust's concurrency model and their experience writing concurrent code, which is crucial for many high-performance or systems programming applications.

5. How would you use Rust for systems programming?

Rust is designed for systems programming, with features that enable direct hardware access, predictable performance, and low overhead.

This question can reveal a candidate's understanding of systems programming and their ability to leverage Rust's strengths in this domain.

It also provides an opportunity for the candidate to discuss specific projects or scenarios where they've applied these skills.

6. Can you explain traits? How have you used trait objects in your projects?

Traits in Rust are a way to define shared behavior across types.

A candidate's understanding of traits and trait objects can give insight into their knowledge of Rust's type system and how they design and structure their code.

Their examples of using trait objects in projects can also reflect their practical experience with Rust's more advanced features.

7. How does Rust improve productivity?

This question asks for the candidate's perspective on how Rust impacts developer productivity.

It helps assess the candidate's understanding of Rust's features like its strong static typing system, memory safety, expressive type system, and other aspects that can improve productivity by reducing bugs or making code easier to reason about.

8. Can you explain what a borrow checker is?

The borrow checker is a unique feature of Rust that enforces strict borrowing and lifetime rules to ensure memory safety and prevent data races. Understanding the borrow checker is crucial to write effective Rust code.

This question can help gauge a candidate's depth of knowledge about Rust's core principles and their ability to write safe, efficient code.

9. What’s your methodology for debugging in Rust?

Debugging is a fundamental skill in any programming language.

This question allows you to assess the candidate's familiarity with debugging tools for Rust, such as gdb, lldb, or Rust's built-in testing and debugging features.

Their approach to debugging can also reveal their problem-solving skills and methodologies.

10. How do you manage packages and modules in Rust?

Rust uses a package manager called Cargo and a module system to organize code and manage dependencies. Understanding these tools is essential for effective Rust development.

This question can reveal the candidate's experience with managing Rust projects, their understanding of Rust's package and module systems, and their ability to organize and modularize code effectively.

11. What’s the difference between a panic and an Option in Rust?

This question probes the candidate's understanding of Rust's mechanisms for error handling.

A panic is an unrecoverable error that crashes the program, whereas an Option type is used for handling recoverable errors.

Understanding the distinction and when to use each is crucial for writing robust and reliable Rust code.

12. How does Rust ensure memory safety?

Rust uses a system of ownership with a set of rules that the compiler checks at compile-time to guarantee memory safety, preventing common programming errors like null pointer dereferencing, double free, and data races.

This question can gauge a candidate's understanding of Rust's memory safety features and their ability to write safe, efficient code.

13. In what scenario would you use Rust instead of other programming languages?

This question provides insight into the candidate's understanding of Rust's strengths and weaknesses compared to other languages.

It helps evaluate their ability to choose the right tool for the job and their understanding of when Rust's unique features, like its focus on memory safety and concurrency, would be beneficial.

14. Can you explain how destructive interference is avoided in Rust?

Destructive interference is a term often used to describe a situation where two or more operations interfere with each other leading to unintended consequences.

In the context of Rust, it generally refers to how Rust prevents data races through its ownership, borrowing, and lifetime rules.

This question tests a candidate's understanding of these mechanisms and their ability to write safe concurrent code in Rust.

15. What’s your approach to learning and staying updated with the latest features in Rust?

Rust is a living language that continues to evolve and add new features.

This question can assess the candidate's commitment to continuous learning and their strategies for keeping their skills up-to-date.

Their answer can also provide insight into their capacity to adapt to change, which is crucial in the fast-moving tech industry.

Is there another way to assess Rust skills?

Conducting interviews can be time-consuming and resource-intensive, especially for large-scale hiring processes.

A Rust test can be administered to multiple candidates simultaneously, saving time and effort. The automated scoring and evaluation of skills tests further enhance efficiency.

Plus, the Rust test provides quantifiable data on a candidate's performance, leaving little room for subjective interpretation.

By combining the insights gained from the Rust test and the interview, you can make more informed decisions when hiring candidates with Rust proficiency.