CodeSubmit Interview Series

The 12 Best Rust Interview Questions in 2023

Need to hire your next Rust developer? In that case, you need the right Rust interview questions. Here are our top picks. 

Interviewing Rust developers  

Rust was originally developed by Mozilla and is a general-purpose, multi-paradigm language. It’s designed for performance and safety and is all about writing faster and more reliable software. Rust lets developers control low-level details without the hassle that usually comes with this level of control. Rust is intended for high-performance applications.

To identify the best Rust developers, you need the right interview questions. Here below, we’ll look at interview questions for both junior and senior developers. 

Beginner Rust interview questions

What are the top beginner Rust interview questions? Read on for our top picks for junior Rust developers. 

1. What is Rust?


Rust is a fast systems language with a strong focus on thread safety and reliability. It includes great documentation, a friendly compiler with useful error messages, and a top tooling on the stack or on the heap, which allows for data storing and determines at compile time if there isn’t a need for memory.  

2. What are the benefits of Rust? 


Rust is a fast, memory-efficient, and safe language. It has no runtime, which means that it can power performance-critical services, integrate with other languages, and run on embedded devices. 

Rust also guarantees memory safety and thread safety, which enables you to eliminate many classes of bugs at compile time. 

Furthermore, abstractions in Rust are free. Rust provides extensive documentation, and concurrency is supported by default in Rust. 

3. Explain what cargo is in Rust.


Cargo is the Rust package manager to manage Rust projects. With it, you can build code, download libraries, and rebuild libraries. 

4. What’s the connection between Rust and its reusable code? 


Rust makes it possible to arrange code so that it can be reused through easy organization of modules, structures, and functions. Users can utilize them privately or publicly. 

5. List some of the most important Rust features. 


The most important features in Rust are: 

  • Abstraction at no cost: Rust allows developers to build abstractions without compromising the runtime performance, clarity, or quality of code.

  • Error messaging: Rust makes error messaging extremely clear. Error messages propose misspellings and are presented with (formatting, colors). 

  • Threads without data races: When two or more threads access the same memory address at the same time, a data race occurs. Rust supports threads without data races because of the ownership mechanism; only the owners of objects are transmitted to different threads via the ownership mechanism. Two threads can’t own the same variable with write access. 

  • Move semantics: Rust enables move semantics that allows copy action to be replaced by a move operation when a source object is a temporary object. 

  • Memory safety: Rust uses ownership (a compromise between C’s memory control and Java’s garbage collection) to ensure memory safety. Memory space is owned by variables and is temporarily borrowed by other variables. Rust offers memory safety at compile time without relying on garbage collection. 

6. How safe is Rust compared to C and C++? 


One of the main benefits of Rust in comparison to C is the ability to write safe code. Rust doesn’t, like C does, require memory management or performing pointer arithmetic. In comparison to C++, Rust offers safety by not showing arbitrary behavior if a mistake is made.

7. What are the disadvantages of Rust?


The disadvantages of Rust include:

  • Compilation in Rust can be slow

  • The Rust compiler must be requested to collect with optimizations because they slow down compilation 

  • Rust has a moderately complicated kind system 

Advanced Rust interview questions

What are the top advanced Rust interview questions? Here are the interview questions to ask senior Rust developers.

8. Explain the error handling procedures in Rust.


Error handling in Rust is categorized into three parts. These are: 

  • Recoverable error with results: The program doesn’t stop completely if an error occurs, but instead, it can be interpreted or responded to.  

  • Panic or not to panic: When you are unsure about calling panic or not, you can write code that panics, and the program continues as second. 

  • Unrecoverable errors with panic: Rust’s panic macro activates if something goes wrong with the code. It shows the error message, cleans the code, and quits.

9. Explain how garbage collection is done in Rust.


Rust uses a static garbage collector that uses automated memory management so that memory that is no longer in use is recycled. A single reference, or variable, owns each memory segment. If the variable is out of scope and unavailable, the ownership is transferred to another variable, or the memory is released. 

10. Can an operating system be created entirely in Rust?


Yes, an operating system can be created in Rust; in fact, Rust is used as the primary programming language in many newer operating systems. Rust is also used to create different applications, such as game engines, file systems, and virtual reality simulation engines.

11. Explain how to use &self, self and &mut self in the declaration method.


&self: When Read-only reference is required for the function. 

self: When a value is to be consumed by the function. 

&mut: When a value needs to be mutated by the function when consuming it. 

12. Explain how to declare global variables in Rust. 


Use the const keyword in Rust for compile time computed global constants. Compile time constants are limited in Rust, but primitives can be defined by const declarations. 

Over to you!

There you have it! These are our top Rust interview questions. 

However, interview questions are one part of the recruitment process. You also need to assess your candidates’ technical skills. 

How? With live coding interview tests and take-home coding challenges.

Want to get started right away? 

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