Rust Ecosystem

Core Concepts

• Ownership: Each value has one owner; when owner goes out of scope, value is dropped
• Borrowing: &T allows multiple immutable borrows; &mut T allows exactly one; cannot mix
• Result/Option: Result<T, E> for recoverable errors, Option<T> for optional values; use ? for propagation
• Traits: Define behavior with traits; use derive for common implementations

Borrowing Rules

• &T - multiple simultaneous immutable borrows allowed
• &mut T - exactly one mutable borrow allowed
• Cannot have &mut T while &T exists

Error Handling

// Custom error with thiserror
#[derive(Debug, thiserror::Error)]
enum MyError {
    #[error("IO error: {0}")]
    Io(#[from] std::io::Error),
    #[error("Parse error: {msg}")]
    Parse { msg: String },
}

// Propagate with ?
fn read_config() -> Result<Config, MyError> {
    let content = std::fs::read_to_string("config.toml")?;
    Ok(parse(content)?)
}

Common Traits

• Clone - explicit .clone(); Copy - implicit bitwise copy
• Debug - {:?} formatting; Display - {} formatting
• Default - default value construction
• PartialEq/Eq, PartialOrd/Ord - comparison
• From/Into - type conversions
• Hash - for HashMap/HashSet keys

Project Structure

Cargo.toml
src/
  lib.rs        # Library crate root
  main.rs       # Binary crate root
  bin/          # Additional binaries
tests/          # Integration tests
benches/        # Benchmarks
examples/       # Example code

Cargo.toml

[package]
name = "my-crate"
version = "0.1.0"
edition = "2021"
rust-version = "1.83"

[dependencies]
serde = { version = "1.0", features = ["derive"] }

[lints.clippy]
pedantic = "warn"
unwrap_used = "deny"

[profile.release]
lto = true
codegen-units = 1
strip = true

Workspace

[workspace]
resolver = "2"
members = ["crate-a", "crate-b"]

[workspace.dependencies]
serde = "1.0"
tokio = { version = "1", features = ["full"] }

Member crates inherit with serde.workspace = true.

Anti-Patterns

• unwrap() in library code: Use ? or proper error handling
• Clone abuse: Prefer borrowing when possible
• String for everything: Use enums, newtypes for domain modeling
• Arc<Mutex> overuse: Consider channels or ownership patterns first

Tools

• cargo check - Fast syntax/type check
• cargo clippy -- -D warnings - Linter
• cargo fmt - Formatter
• cargo nextest run - Better test runner
• cargo audit - Security vulnerability scanning
• cargo tree - Dependency tree

rustfmt.toml

edition = "2021"
max_width = 100
imports_granularity = "Crate"
group_imports = "StdExternalCrate"

Context7 Reference

• Rust Book: /rust-lang/book
• Cargo: /rust-lang/cargo.git
• Clippy: /rust-lang/rust-clippy