rust-development

Expert knowledge for modern systems programming with Rust, focusing on memory safety, fearless concurrency, and zero-cost abstractions.

When to Use This Skill

| Use this skill when... | Use sibling skill instead when... | |---|---| | Writing Rust code, ownership, lifetimes, async/await | Configuring lint rules in detail -- use clippy-advanced | | Choosing crates from the ecosystem (Tokio, Serde) | Detecting unused dependencies -- use cargo-machete | | Designing module structure or trait hierarchies | Running tests with parallel isolation -- use cargo-nextest | | Learning idiomatic Rust patterns and edition features | Generating coverage reports -- use cargo-llvm-cov |

Core Expertise

Modern Rust Ecosystem

• Cargo: Build system, package manager, and workspace management
• Rustc: Compiler optimization, target management, and cross-compilation
• Clippy: Linting for idiomatic code and performance improvements
• Rustfmt: Consistent code formatting following Rust style guidelines
• Rust-analyzer: Advanced IDE support with LSP integration

Language Features

• Rust 2024 edition: RPITIT, async fn in traits, impl Trait improvements
• Const generics and compile-time computation
• Generic associated types (GATs)
• Let-else patterns and if-let chains

Key Capabilities

Ownership & Memory Safety

• Implement ownership patterns with borrowing and lifetimes
• Design zero-copy abstractions and efficient memory layouts
• Apply RAII patterns through Drop trait and smart pointers (Box, Rc, Arc)
• Leverage interior mutability patterns (Cell, RefCell, Mutex, RwLock)
• Use Pin/Unpin for self-referential structures

Async Programming & Concurrency

• Tokio: Async runtime for high-performance network applications
• async-std: Alternative async runtime with familiar API design
• Futures: Composable async abstractions and stream processing
• Rayon: Data parallelism with work-stealing thread pools
• Design lock-free data structures with atomics and memory ordering

Error Handling & Type Safety

• Design comprehensive error types with thiserror and anyhow
• Implement Result<T, E> and Option<T> patterns effectively
• Use pattern matching for exhaustive error handling
• Apply type-state patterns for compile-time guarantees

Performance Optimization

• Profile with cargo-flamegraph, perf, and criterion benchmarks
• Optimize with SIMD intrinsics and auto-vectorization
• Implement zero-cost abstractions and inline optimizations
• Use unsafe code judiciously with proper safety documentation

Testing & Quality Assurance

• Unit Testing: #[test] modules with assertions
• Integration Testing: tests/ directory for end-to-end validation
• Criterion: Micro-benchmarking with statistical analysis
• Miri: Undefined behavior detection in unsafe code
• Fuzzing: cargo-fuzz for security and robustness testing

Essential Commands

# Project setup
cargo new my-project      # Binary crate
cargo new my-lib --lib    # Library crate
cargo init                # Initialize in existing directory
# From a template repo instead of an empty crate — see the cargo-generate skill
cargo generate --git <template-url> --name my-project

# Development workflow
cargo build                      # Debug build
cargo build --release           # Optimized build
cargo run                       # Build and run
cargo run --release             # Run optimized
cargo test                      # Run all tests
cargo test --lib               # Library tests only
cargo bench                     # Run benchmarks

# Code quality
cargo clippy                    # Lint code
cargo clippy -- -W clippy::pedantic  # Stricter lints
cargo fmt                       # Format code
cargo fmt --check              # Check formatting
cargo fix                       # Auto-fix warnings

# Dependencies
cargo add serde --features derive  # Add dependency
cargo update                       # Update deps
cargo audit                        # Security audit
cargo deny check                   # License/advisory check

# Advanced tools
cargo expand                    # Macro expansion
cargo flamegraph               # Profile with flame graph
cargo doc --open               # Generate and open docs
cargo miri test                # Check for UB

# Cross-compilation
rustup target add wasm32-unknown-unknown
cargo build --target wasm32-unknown-unknown

Best Practices

Idiomatic Rust Patterns

// Use iterators over manual loops
let sum: i32 = numbers.iter().filter(|x| **x > 0).sum();

// Prefer combinators for Option/Result
let value = config.get("key")
    .and_then(|v| v.parse().ok())
    .unwrap_or_default();

// Use pattern matching effectively
match result {
    Ok(value) if value > 0 => process(value),
    Ok(_) => handle_zero(),
    Err(e) => return Err(e.into()),
}

// Let-else for early returns
let Some(config) = load_config() else {
    return Err(ConfigError::NotFound);
};

Project Structure

my-project/
├── Cargo.toml
├── src/
│   ├── lib.rs        # Library root
│   ├── main.rs       # Binary entry point
│   ├── error.rs      # Error types
│   └── modules/
│       └── mod.rs
├── tests/            # Integration tests
├── benches/          # Benchmarks
└── examples/         # Example programs

Error Handling

use thiserror::Error;

#[derive(Error, Debug)]
pub enum AppError {
    #[error("IO error: {0}")]
    Io(#[from] std::io::Error),

    #[error("parse error: {message}")]
    Parse { message: String },

    #[error("not found: {0}")]
    NotFound(String),
}

pub type Result<T> = std::result::Result<T, AppError>;

Common Crates | Crate | Purpose | |-------|---------| | serde | Serialization/deserialization | | tokio | Async runtime | | reqwest | HTTP client | | sqlx | Async SQL | | clap | CLI argument parsing | | tracing | Logging/diagnostics | | anyhow | Application errors | | thiserror | Library errors |

For detailed async patterns, unsafe code guidelines, WebAssembly compilation, embedded development, and advanced debugging, see REFERENCE.md.