Rust 1.80 stabilizes LazyCell and LazyLock, two new types that can be used to delay initialization of data until the first time they are accessed. Additionally, it allows variadic functions without a named parameter for compatibility with C23.
LazyLock is indicated for general use, LazyCell removes concurrency overhead, OnceLock and OnceCell support more complex initialization logic and use-cases. Lazy types enable delay of initialization until data is accessed.
Exclusive ranges are added for pattern matching in Rust 1.80. Inclusive endpoints remain supported as a..=b or ..=b, while exclusive ranges can now be used as a..b and ..b.
Collection
[
|
...
]