overrideKeyword

Explanation

override has been reserved since the 2015 edition, part of the Rust Reference's original reserved-keyword list. Like final and virtual, it reads as a piece of vocabulary from class-based inheritance (as in Java, C#, or C++, where override marks a method that intentionally replaces a base class's implementation). Rust has no such inheritance model — trait implementations aren't "overridden," they're separate impl blocks — so there is no concrete proposal attaching real behavior to override today. It's speculative, held in reserve alongside final and virtual in case some future mechanism gives Rust a reason to distinguish an intentional override from an accidental name collision.

Using override as an ordinary identifier is a compile error today. The raw-identifier form r#override is legal, the same escape hatch every reserved keyword offers.

Usage examples

Using the raw-identifier escape hatch

let override = 5;     // error: expected identifier, found reserved keyword `override`
let r#override = 5;   // ok: the raw-identifier form escapes the reservation

Explanation

Embedded support: Full

Full support. Keyword reservation is a lexer-level fact, identical in #![no_std] and hosted Rust alike — override carries no defined meaning on any target, so there's no embedded-specific behavior to describe.

Usage examples

The `override` reservation, unaffected by target

let override = 5;     // error: expected identifier, found reserved keyword `override`, on every target
let r#override = 5;   // ok: the raw-identifier form escapes the reservation, on every target