Rust · systems track · graded by cargo test

Learn Rust until the borrow checker clicks.Real cargo tests. Real capstones. No videos.

Three courses that take a working programmer from ownership and borrowing to threads, channels and systems capstones. Every exercise is graded by the borrow checker plus real cargo tests — so “it compiles” is a milestone, not the finish line. Built for people who already program.

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rust-1 · ownership · borrowingcargo test

// Return the longest word without taking ownership of the input.
// The grader runs real cargo tests — a borrow-checker error is a failing build.
fn longest_word(text: &str) -> &str {
    text.split_whitespace()
        .max_by_key(|word| word.len())
        .unwrap_or("")
}

fn main() {
    let report = String::from("ownership moves, borrows do not");
    let longest = longest_word(&report);
    // report is still usable here — we only borrowed it.
    println!("{longest} ({} chars) in: {report}", longest.len());
}

test result: ok. 4 passed; 0 failed · borrow checker clean

RUST 1

Foundations, Ownership & Errors

Rust for people who already program — cargo, ownership and borrowing, enums and Result, ending in your first grep clone.

RUST 2

Types, Collections & Smart Pointers

Structs, traits and generics; iterators, closures and lifetimes; then Box, Rc and RefCell — and you build a working Unix shell.

RUST 3

Concurrency & Systems Capstones

The systems tier — threads, channels and Arc<Mutex<T>>, an async survey, then an HTTP server from raw TCP and a persistent key-value store.

The tests decide, not vibes

Your code runs against real cargo test suites. The borrow checker plus hidden tests make pass/fail deterministic — the AI never grades you.

It adapts to you

Fighting the borrow checker? The game diagnoses why — moves, borrows or lifetimes — and builds targeted practice. Already own ownership? It moves you up.

Ship real systems

Capstones like a grep clone, a Unix shell, an HTTP server from raw TCP and a key-value store — the answer to being stuck after The Book. Ship a portfolio, not just streaks.

Your first passing cargo test is minutes away.

Start the Rust track — free

Free tier is genuinely free — every banked exercise is playable. We gate AI help and fresh generation, never the content.