⚾️ 🤟🏻 📮 Rust 1.45.0：稳定功能性程序宏，修复转换缺陷 ♾ 👍🏽 🚩

Rust团队很高兴地宣布发布新版本1.45.0。Rust是一种编程语言，它使任何人都可以创建可靠而高效的软件。

如果使用tools安装了Rust的早期版本rustup，那么要升级到1.45.0版，您只需运行以下命令：

rustup update stable

如果你不已经拥有了它rustup，你可以安装它从我们的网站上相应的页面，也期待它在GitHub上。

稳定版1.45.0中包含什么

该版本包含两个重大更改：修复了整数和浮点数之间转换中的长期缺陷，以及稳定了至少一个Web框架在稳定的Rust上运行所必需的功能。

纠正转换中的缺陷

最初的10184期于2013年10月开放，历时一年半才发布Rust 1.0。由于它rustc使用LLVM作为其后端编译器，因此在编写如下代码时：

pub fn cast(x: f32) -> u8 {
    x as u8
}

1.44.0及更早版本中的Rust编译器生成以下LLVM-IR：

define i8 @_ZN10playground4cast17h1bdf307357423fcfE(float %x) unnamed_addr #0 {
start:
  %0 = fptoui float %x to i8
  ret i8 %0
}

fptoui "floating point to unsigned integer".

, :

‘fptoui’ ( ) . ty2, .

The ‘fptoui’ instruction converts its floating-point operand into the nearest (rounding towards zero) unsigned integer value. If the value cannot fit in ty2, the result is a poison value.

, , . , : , .

, , :

fn cast(x: f32) -> u8 {
    x as u8
}

fn main() {
    let f = 300.0;

    let x = cast(f);

    println!("x: {}", x);
}

Rust 1.44.0 "x: 0", .. , . «» ( unsafe ) — , . I-unsound, .

. , , .

as " " (saturating cast),
unsafe , .

, :

array[i] , , array i + 1 ,
unsafe { array.get_unchecked(i) }, .

, ? :

fn cast(x: f32) -> u8 {
    x as u8
}

fn main() {
    let too_big = 300.0;
    let too_small = -100.0;
    let nan = f32::NAN;

    println!("too_big_casted = {}", cast(too_big));
    println!("too_small_casted = {}", cast(too_small));
    println!("not_a_number_casted = {}", cast(nan));
}

too_big_casted = 255
too_small_casted = 0
not_a_number_casted = 0

. ( ). NaN .

API :

let x: f32 = 1.0;
let y: u8 = unsafe { x.to_int_unchecked() };

, , . , , , .

,

Rust 1.30.0 « ». , gnome-class:

Gnome- — Rust. Rust- -, , GObject, , , GObject. , .

gobject_gen! {
    class MyClass: GObject {
        foo: Cell<i32>,
        bar: RefCell<String>,
    }

    impl MyClass {
        virtual fn my_virtual_method(&self, x: i32) {
            ... do something with x ...
        }
    }
}

" " — , , gobject_gen! .

Rust 1.45.0 :

// ,      "mac"

mac!(); //  , ,    

//    3 :
fn main() {
  let expr = mac!(); //  

  match expr {
      mac!() => {} //  
  }

  mac!(); //  
}

, , : Rocket. - Rocket, 2016 , , Rust. ", " :

#[macro_use] extern crate rocket;

#[get("/<name>/<age>")]
fn hello(name: String, age: u8) -> String {
    format!("Hello, {} year old named {}!", age, name)
}

#[launch]
fn rocket() -> rocket::Rocket {
    rocket::ignite().mount("/hello", routes![hello])
}

Rocket . , , Rocket proc_macro_hygiene . , , ! Rocket. !

Rocket , , :)

Rust 1.45.0 :

char :

for ch in 'a'..='z' {
    print!("{}", ch);
}
println!();
//  "abcdefghijklmnopqrstuvwxyz"

, Cargo Clippy .

1.45.0

, Rust 1.45.0. , !

Rust - . , .

nlinker, funkill, Hirrolot blandger.

Rust 1.45.0：稳定功能性程序宏，修复转换缺陷

稳定版1.45.0中包含什么

纠正转换中的缺陷

,

1.45.0

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