테스트

Rust에는 암시적 타입 변환이 없지만 as를 사용한 명시적 변환은 지원됩니다. 이는 일반적으로 C 의미론을 따라 정의됩니다.

fn main() {
    let value: i64 = 1000;
    println!("as u16: {}", value as u16);
    println!("as i16: {}", value as i16);
    println!("as u8: {}", value as u8);
}

as의 결과는 Rust에서 항상 정의되며 여러 플랫폼에서 일관됩니다. 이는 기호를 변경하거나 더 작은 타입으로 변환할 때의 직관과 일치하지 않을 수 있습니다. 문서를 확인하고 명확하게 설명해 주세요.

Casting with as is a relatively sharp tool that is easy to use incorrectly, and can be a source of subtle bugs as future maintenance work changes the types that are used or the ranges of values in types. Casts are best used only when the intent is to indicate unconditional truncation (e.g. selecting the bottom 32 bits of a u64 with as u32, regardless of what was in the high bits).

For infallible casts (e.g. u32 to u64), prefer using From or Into over as to confirm that the cast is in fact infallible. For fallible casts, TryFrom and TryInto are available when you want to handle casts that fit differently from those that don’t.