What Rust is¶

Level: 101 · for newcomers

One line: Rust is a compiled systems language with no garbage collector, whose compiler proves memory safety and freedom from data races for every program it accepts outside unsafe — and most of what makes it feel different follows from that one decision.

Stub — an outline, not a lesson. There is no runnable example behind this page yet, so nothing on it has been through the check that backs every other claim in this library. The bullets below are the questions the finished page has to answer.

What it has to cover¶

The one-paragraph definition, and which words in it are claims a program can check: compiled (see compiled or interpreted), no garbage collector, memory-safe without unsafe
Where memory management went instead of a GC — ownership, borrowing and Drop — as three sentences, each pointing at the section that proves it
What "safe" does not promise: no leaks, no deadlocks, no logic errors, no panics — and which of those the library shows happening in safe code
The release train and editions: a new stable compiler every six weeks, and an edition (2015, 2018, 2021, 2024) as the one place breaking syntax changes are allowed — why a 2015 crate still builds with today's compiler
What Rust is used for today, as evidence rather than adjectives: the Linux kernel, Android, Windows, browsers, CLIs rewritten in it — each linked to its source
Who makes it: the Rust Project's teams and RFCs versus the Rust Foundation — a pointer to the Rust Project

The trap it exists for¶

Reading "memory-safe" as "cannot crash". A Rust program panics, leaks with Box::leak or an Rc cycle, and deadlocks on two Mutexes — all in safe code. What it rules out is a narrower and more valuable list: use-after-free, double free, data races, reading uninitialized memory, out-of-bounds access that silently continues.

Where this sits¶

Benefits of Rust takes Google's list of twenty selling points apart claim by claim, and measured claims checks the numbers people quote. This page is the definition those two argue about.

If you are coming from another language¶

C and C++. The same model of the machine — values on the stack, explicit heap, no runtime — with the lifetime rules you kept in your head moved into the type checker. The C library's Strings chapter ↗ is a tour of what that bookkeeping costs when nobody checks it.
Python. The opposite trade on every axis: Python checks types and frees memory at run time, Rust at compile time. What transfers is the tooling experience — cargo feels closer to uv than to make.
Go. Also compiled, also one binary, also built for concurrency — but Go keeps a garbage collector and a runtime scheduler, and lets a data race compile. The Go library's race detector ↗ page is the run-time check Rust moves into the build.
Java. The type system will feel familiar and the absence of null, exceptions, inheritance and a GC will not. Generics are compiled per type rather than erased.

Po polsku¶

Rust to język kompilowany, bez odśmiecania pamięci (garbage collector), którego kompilator dowodzi bezpieczeństwa pamięci i wątków dla każdego programu przyjętego poza blokiem unsafe. Najczęstsze nieporozumienie to utożsamienie „bezpieczny” z „nie może się wywrócić”: panic!, wyciek pamięci i zakleszczenie są w bezpiecznym Ruście jak najbardziej możliwe — wykluczone są za to błędy użycia po zwolnieniu, podwójnego zwolnienia i wyścigi danych.

Szukaj po polsku: co to jest Rust · bezpieczeństwo pamięci · edycje Rusta · what is rust programming language · rust memory safety guarantees