Project 7: Implement a Self-Referential Struct with Pin

A self-referential struct (e.g., a struct containing a String and a &str pointing into it) using Pin to prevent it from being moved.

Quick Reference

Attribute Value
Primary Language Rust
Alternative Languages None
Difficulty Level 5: Master
Time Estimate 2-3 weeks
Knowledge Area Unsafe Rust / Pin API
Tooling Rust std::pin
Prerequisites All previous projects, deep Rust understanding

What You Will Build

A self-referential struct (e.g., a struct containing a String and a &str pointing into it) using Pin to prevent it from being moved.

Why It Matters

This project builds core skills that appear repeatedly in real-world systems and tooling.

Core Challenges

  • Creating a self-referential struct → maps to understanding why they’re normally forbidden
  • Using Pin to prevent moves → maps to Pin<Box<T>> and !Unpin
  • Implementing safe projections → maps to pin-project crate patterns
  • Understanding async/await connection → maps to why futures need Pin

Key Concepts

  • Pin and Unpin: “Asynchronous Programming in Rust” book
  • Self-Referential Structs: “The Rustonomicon” - Self-referential structs chapter
  • Pin RFC: RFC 2349 documentation
  • pin-project: Study this crate’s macros and documentation

Real-World Outcome

Deliver a working demo with observable output that proves the feature is correct.

Implementation Guide

  1. Reproduce the simplest happy-path scenario.
  2. Build the smallest working version of the core feature.
  3. Add input validation and error handling.
  4. Add instrumentation/logging to confirm behavior.
  5. Refactor into clean modules with tests.

Milestones

  • Milestone 1: Minimal working program that runs end-to-end.
  • Milestone 2: Correct outputs for typical inputs.
  • Milestone 3: Robust handling of edge cases.
  • Milestone 4: Clean structure and documented usage.

Validation Checklist

  • Output matches the real-world outcome example
  • Handles invalid inputs safely
  • Provides clear errors and exit codes
  • Repeatable results across runs

References

  • Main guide: RUST_BORROW_CHECKER_LIFETIME_PHILOSOPHY.md
  • “The Rustonomicon” + Pin RFC