Rust: ownership, borrowing, and lifetimes

What you’ll practice

This quiz targets the core Rust concepts that unlock safe, fast code: ownership moves, borrowing (shared vs mutable), and lifetimes. Expect scenarios that mirror real compiler messages and require you to pick the best fix.

Every question is multiple-choice with 4 options and no timer, so you can reason through each snippet carefully. You can also choose the question count and difficulty before starting to match your study session.

Common pitfalls to watch for

Many mistakes come from mixing mutable and immutable borrows, returning references to local data, or misunderstanding when a value is moved. Another frequent trap is adding lifetime annotations that “look right” but don’t reflect the actual relationships between references.

• Confusing moves with copies (especially with String, Vec, and structs)
• Holding a borrow across a mutation or across an iterator loop
• Creating dangling references by returning refs to temporaries/locals
• Overusing 'static or adding lifetimes where elision already works
• Missing reborrows and the scope of a mutable borrow

How the difficulty stays balanced

Difficulty is mixed: easier items build fundamentals (moves, basic borrowing), while harder ones cover lifetime relationships, trait bounds, and tricky control-flow scopes. If you want a smoother ramp, start with easier difficulty and fewer questions, then increase length or switch to mixed once your accuracy improves.