rust-pro

Modern Rust

Guidance for building correct, fast Rust on the 2024 edition. The throughline is using the compiler to prove properties at build time, then optimizing what is left -- safety and performance are not in tension when the type system carries the weight.

How to approach a Rust task

1. Pin down the real constraints first: latency and throughput targets, safety requirements, and which runtime (if any) the system can adopt.
2. Decide the concurrency model and the crate ecosystem before writing much code -- async runtime, web framework, data layer.
3. Build with tests and lints wired in from the start.
4. Profile only after it works, then optimize the hot paths the data points to.

This skill suits services, libraries, and systems tooling, and is most valuable for ownership/lifetime puzzles, async architecture, and safety-preserving optimization. It is overkill when you just need a quick dynamic script or only touch basic syntax, and it does not apply where Rust cannot enter the stack.

Language features worth mastering

The modern, long-stable surface area is large. The pieces that pay off most often:

• Const generics and improved inference for expressing size and shape at the type level.
• Generic associated types (GATs) and richer trait bounds for abstractions that were previously impossible.
• Pattern matching with destructuring and guards as a primary control-flow tool.
• Const evaluation for moving work to compile time.
• Both flavors of macro -- declarative macro_rules! and procedural/derive -- for cutting boilerplate.
• The module and visibility system for clean API surfaces.
• Result, Option, and custom error types as the backbone of error handling.

Ownership and memory

This is where Rust earns its guarantees, so internalize it:

• Ownership, borrowing, and move semantics -- the model the borrow checker enforces.
• Shared ownership via Rc/Arc, with Weak to break cycles.
• The smart-pointer toolbox: Box for heap allocation, RefCell for interior mutability, Mutex/RwLock for shared mutable state across threads.
• Zero-cost abstractions and deliberate memory layout.
• RAII -- tie resource cleanup to scope via Drop.
• Phantom types and zero-sized types to encode invariants at no runtime cost.
• Custom allocators and pooling when the default allocator is the bottleneck.