Lints

rustdoc 提供了 lint 来帮助你编写和测试文档。你可以像使用其他 lint 一样使用它们，方法如下：

#![allow(unused)]
#![allow(rustdoc::broken_intra_doc_links)] // allows the lint, no diagnostics will be reported
#![warn(rustdoc::broken_intra_doc_links)] // warn if there are broken intra-doc links
#![deny(rustdoc::broken_intra_doc_links)] // error if there are broken intra-doc links
fn main() {
}

请注意，除了 missing_docs，这些 lint 仅在运行 rustdoc 时可用，而不是 rustc 时。

以下是 rustdoc 提供的 lint 列表：

broken_intra_doc_links

此 lint 默认发出警告。此 lint 检测 内部文档链接 何时无法解析。例如：

#![allow(unused)]
fn main() {
/// I want to link to [`Nonexistent`] but it doesn't exist!
pub fn foo() {}
}

你会收到一个警告，提示：

warning: unresolved link to `Nonexistent`
 --> test.rs:1:24
  |
1 | /// I want to link to [`Nonexistent`] but it doesn't exist!
  |                        ^^^^^^^^^^^^^ no item named `Nonexistent` in `test`

当存在歧义时，它也会发出警告，并建议如何消除歧义：

#![allow(unused)]
fn main() {
/// [`Foo`]
pub fn function() {}

pub enum Foo {}

pub fn Foo(){}
}

warning: `Foo` is both an enum and a function
 --> test.rs:1:6
  |
1 | /// [`Foo`]
  |      ^^^^^ ambiguous link
  |
  = note: `#[warn(rustdoc::broken_intra_doc_links)]` on by default
help: to link to the enum, prefix with the item type
  |
1 | /// [`enum@Foo`]
  |      ^^^^^^^^^^
help: to link to the function, add parentheses
  |
1 | /// [`Foo()`]
  |      ^^^^^^^

private_intra_doc_links

此 lint 默认发出警告。此 lint 检测从公共项到私有项的内部文档链接。例如：

#![allow(unused)]
#![warn(rustdoc::private_intra_doc_links)] // note: unnecessary - warns by default.

fn main() {
/// [private]
pub fn public() {}
fn private() {}
}

这会发出一个警告，提示该链接在文档中出现时将会断开：

warning: public documentation for `public` links to private item `private`
 --> priv.rs:1:6
  |
1 | /// [private]
  |      ^^^^^^^ this item is private
  |
  = note: `#[warn(rustdoc::private_intra_doc_links)]` on by default
  = note: this link will resolve properly if you pass `--document-private-items`

请注意，这取决于你是否传递 --document-private-items 而有不同的行为！如果你为私有项生成文档，它仍然会生成链接，尽管会发出警告：

warning: public documentation for `public` links to private item `private`
 --> priv.rs:1:6
  |
1 | /// [private]
  |      ^^^^^^^ this item is private
  |
  = note: `#[warn(rustdoc::private_intra_doc_links)]` on by default
  = note: this link resolves only because you passed `--document-private-items`, but will break without

missing_docs

此 lint 默认允许。它检测缺少文档的项目。例如：

#![warn(missing_docs)]

pub fn undocumented() {}
fn main() {}

然后，undocumented 函数将有以下警告：

warning: missing documentation for a function
  --> your-crate/lib.rs:3:1
   |
 3 | pub fn undocumented() {}
   | ^^^^^^^^^^^^^^^^^^^^^

请注意，与其他 rustdoc lint 不同，此 lint 也可直接从 rustc 使用。

missing_crate_level_docs

此 lint 默认允许。它检测 crate 根目录是否没有文档。例如：

#![allow(unused)]
#![warn(rustdoc::missing_crate_level_docs)]
fn main() {
}

这将生成以下警告：

warning: no documentation found for this crate's top-level module
  |
  = help: The following guide may be of use:
          http://doc.rust-lang.net.cn/nightly/rustdoc/how-to-write-documentation.html

目前，默认设置为“允许”，但将来计划将其设为警告。 这旨在为新用户提供关于如何编写 crate 文档的指导，通过引导他们了解一些入门说明，而不会像 missing_docs 可能那样提供大量的警告。

missing_doc_code_examples

此 lint 默认允许，并且是 仅限 nightly。它检测文档块何时缺少代码示例。例如：

#![warn(rustdoc::missing_doc_code_examples)]

/// There is no code example!
pub fn no_code_example() {}
fn main() {}

然后，no_code_example 函数将有以下警告：

warning: Missing code example in this documentation
  --> your-crate/lib.rs:3:1
   |
LL | /// There is no code example!
   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

要修复此 lint，你需要在文档块中添加代码示例：

#![allow(unused)]
fn main() {
/// There is no code example!
///
/// ```
/// println!("calling no_code_example...");
/// no_code_example();
/// println!("we called no_code_example!");
/// ```
pub fn no_code_example() {}
}

private_doc_tests

此 lint 默认允许。它检测私有项上的文档测试。例如：

#![warn(rustdoc::private_doc_tests)]

mod foo {
    /// private doc test
    ///
    /// ```
    /// assert!(false);
    /// ```
    fn bar() {}
}
fn main() {}

这将给出：

warning: Documentation test in private item
  --> your-crate/lib.rs:4:1
   |
 4 | /     /// private doc test
 5 | |     ///
 6 | |     /// ```
 7 | |     /// assert!(false);
 8 | |     /// ```
   | |___________^

invalid_codeblock_attributes

此 lint 默认发出警告。它检测文档示例中代码块的属性，这些属性可能具有类型错误的数值。例如：

#![allow(unused)]
#![warn(rustdoc::invalid_codeblock_attributes)]  // note: unnecessary - warns by default.

fn main() {
/// Example.
///
/// ```should-panic
/// assert_eq!(1, 2);
/// ```
pub fn foo() {}
}

这将给出：

warning: unknown attribute `should-panic`. Did you mean `should_panic`?
 --> src/lib.rs:1:1
  |
1 | / /// Example.
2 | | ///
3 | | /// ```should-panic
4 | | /// assert_eq!(1, 2);
5 | | /// ```
  | |_______^
  |
  = note: `#[warn(rustdoc::invalid_codeblock_attributes)]` on by default
  = help: the code block will either not be tested if not marked as a rust one or won't fail if it doesn't panic when running

在上面的示例中，正确的形式是 should_panic。这有助于检测一些常见属性的拼写错误。

invalid_html_tags

此 lint 默认发出警告。它检测未关闭或无效的 HTML 标签。例如：

#![allow(unused)]
#![warn(rustdoc::invalid_html_tags)]

fn main() {
/// <h1>
/// </script>
pub fn foo() {}
}

这将给出：

warning: unopened HTML tag `script`
 --> foo.rs:1:1
  |
1 | / /// <h1>
2 | | /// </script>
  | |_____________^
  |
  note: the lint level is defined here
 --> foo.rs:1:9
  |
1 | #![warn(rustdoc::invalid_html_tags)]
  |         ^^^^^^^^^^^^^^^^^^^^^^^^^^

warning: unclosed HTML tag `h1`
 --> foo.rs:1:1
  |
1 | / /// <h1>
2 | | /// </script>
  | |_____________^

warning: 2 warnings emitted

invalid_rust_codeblocks

此 lint 默认发出警告。它检测文档示例中无效的 Rust 代码块（例如，空的、无法解析为 Rust 的代码）。例如：

#![allow(unused)]
fn main() {
/// Empty code blocks (with and without the `rust` marker):
///
/// ```rust
/// ```
///
/// Invalid syntax in code blocks:
///
/// ```rust
/// '<
/// ```
pub fn foo() {}
}

这将给出：

warning: Rust code block is empty
 --> lint.rs:3:5
  |
3 |   /// ```rust
  |  _____^
4 | | /// ```
  | |_______^
  |
  = note: `#[warn(rustdoc::invalid_rust_codeblocks)]` on by default

warning: could not parse code block as Rust code
  --> lint.rs:8:5
   |
8  |   /// ```rust
   |  _____^
9  | | /// '<
10 | | /// ```
   | |_______^
   |
   = note: error from rustc: unterminated character literal

bare_urls

此 lint 默认发出警告。它检测不是链接的 URL。例如：

#![allow(unused)]
#![warn(rustdoc::bare_urls)] // note: unnecessary - warns by default.

fn main() {
/// http://example.org
/// [http://example.net]
pub fn foo() {}
}

这将给出：

warning: this URL is not a hyperlink
 --> links.rs:1:5
  |
1 | /// http://example.org
  |     ^^^^^^^^^^^^^^^^^^ help: use an automatic link instead: `<http://example.org>`
  |
  = note: `#[warn(rustdoc::bare_urls)]` on by default

warning: this URL is not a hyperlink
 --> links.rs:3:6
  |
3 | /// [http://example.net]
  |      ^^^^^^^^^^^^^^^^^^ help: use an automatic link instead: `<http://example.net>`

warning: 2 warnings emitted

unescaped_backticks

此 lint 默认允许。它检测未转义的反引号 (`)。这通常意味着内联代码已损坏。例如：

#![allow(unused)]
#![warn(rustdoc::unescaped_backticks)]

fn main() {
/// `add(a, b) is the same as `add(b, a)`.
pub fn add(a: i32, b: i32) -> i32 { a + b }
}

这将给出：

warning: unescaped backtick
 --> src/lib.rs:3:41
  |
3 | /// `add(a, b) is the same as `add(b, a)`.
  |                                         ^
  |
note: the lint level is defined here
 --> src/lib.rs:1:9
  |
1 | #![warn(rustdoc::unescaped_backticks)]
  |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
help: a previous inline code might be longer than expected
  |
3 | /// `add(a, b)` is the same as `add(b, a)`.
  |               +
help: if you meant to use a literal backtick, escape it
  |
3 | /// `add(a, b) is the same as `add(b, a)\`.
  |                                         +

warning: 1 warning emitted

redundant_explicit_links

此 lint 默认发出警告。它检测与计算出的自动链接相同的显式链接。这通常意味着可以删除显式链接。例如：

#![allow(unused)]
#![warn(rustdoc::redundant_explicit_links)] // note: unnecessary - warns by default.

fn main() {
/// add takes 2 [`usize`](usize) and performs addition
/// on them, then returns result.
pub fn add(left: usize, right: usize) -> usize {
    left + right
}
}

这将给出：

error: redundant explicit rustdoc link
  --> src/lib.rs:3:27
   |
3  | /// add takes 2 [`usize`](usize) and performs addition
   |                           ^^^^^
   |
   = note: Explicit link does not affect the original link
note: the lint level is defined here
  --> src/lib.rs:1:9
   |
1  | #![deny(rustdoc::redundant_explicit_links)]
   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   = help: Remove explicit link instead