Rust Cargo Check

Rust: Prefer cargo check Over cargo build

Key Principle

When working with Rust code, use cargo check to verify code compiles. Only use cargo build when you actually need to run the resulting executable.

Why cargo check is Preferred

cargo check skips the code generation and linking phases, making it significantly faster than cargo build - often 2-5x faster or more.

When to Use Each Command

Use cargo check when:

• Making code changes and verifying they compile
• Iterating on fixes for compiler errors
• Refactoring code
• Adding new functions, structs, or modules
• Fixing type errors
• Any time you just need to know "does this compile?"

# Quick compilation check
cargo check

# Check with all features
cargo check --all-features

# Check in release mode (catches some additional warnings)
cargo check --release

Use cargo build when:

• You need to run the executable afterward
• You're about to execute cargo run
• You need to test the actual binary output
• You're preparing a release artifact

# Build and run
cargo build --release && ./target/release/myapp

# Or just use cargo run (which builds implicitly)
cargo run --release -- <args>

Workflow Example

Fixing a Compile Error

# 1. Make code changes to fix the error

# 2. Quick check - does it compile?
cargo check

# 3. If errors remain, fix and check again
cargo check

# 4. Once it compiles, run tests
cargo test

# 5. Only build if you need to run the binary
cargo build --release

Iterating on Code Changes

# Edit code...
cargo check    # Fast feedback

# Edit more...
cargo check    # Fast feedback

# Edit more...
cargo check    # Fast feedback

# Ready to test the actual program
cargo run --release -- <args>

Common Patterns

After Editing Rust Files

# DO: Quick compile check
cargo check

# DON'T: Slow full build just to check compilation
cargo build

Before Running Tests

# Tests compile the code anyway, so just run them directly
cargo test

# No need to cargo build first

When You Need to Run the Binary

# cargo run builds automatically, so use it directly
cargo run --release -- build -m //mode:win_dev -t //target:name

# Or build then run separately if you prefer
cargo build --release
./target/release/anubis build -m //mode:win_dev -t //target:name

Summary

Default to cargo check - it's your fast feedback loop for Rust development.