dead_code 和未使用的 lint 有什么区别？

Question

之间有什么区别

#[allow(dead_code)]
// ...some code

和

#[allow(unused)]
// ...some code

Answer 1

dead_code是一种特定的 lint，定义为：

declare_lint! {
    pub DEAD_CODE,
    Warn,
    "detect unused, unexported items"
}

unused是由许多其他lint组成的lint 组dead_code。它被定义为：

add_lint_group!(
    "unused",
    UNUSED_IMPORTS,
    UNUSED_VARIABLES,
    UNUSED_ASSIGNMENTS,
    DEAD_CODE,
    UNUSED_MUT,
    UNREACHABLE_CODE,
    UNREACHABLE_PATTERNS,
    OVERLAPPING_PATTERNS,
    UNUSED_MUST_USE,
    UNUSED_UNSAFE,
    PATH_STATEMENTS,
    UNUSED_ATTRIBUTES,
    UNUSED_MACROS,
    UNUSED_ALLOCATION,
    UNUSED_DOC_COMMENTS,
    UNUSED_EXTERN_CRATES,
    UNUSED_FEATURES,
    UNUSED_LABELS,
    UNUSED_PARENS,
    UNUSED_BRACES,
    REDUNDANT_SEMICOLONS
);