Rollup merge of rust-lang#103484 - saschanaz:patch-2, r=ehuss

Add `rust` to `let_underscore_lock` example

Currently https://doc.rust-lang.org/beta/rustc/lints/listing/deny-by-default.html#let-underscore-lock has no colored grammar and raw `{{produces}}` command is exposed.

compiler/rustc_lint/src/let_underscore.rs

@@ -57,7 +57,7 @@ declare_lint! {
  /// of at end of scope, which is typically incorrect.
  ///
  /// ### Example
- /// ```compile_fail
+ /// ```rust,compile_fail
  /// use std::sync::{Arc, Mutex};
  /// use std::thread;
  /// let data = Arc::new(Mutex::new(0));

compiler/rustc_lint/src/opaque_hidden_inferred_bound.rs

@@ -26,19 +26,23 @@ declare_lint! {
  ///
  /// ### Example
  ///
- /// ```
+ /// ```rust
+ /// trait Duh {}
+ ///
+ /// impl Duh for i32 {}
+ ///
  /// trait Trait {
- /// type Assoc: Send;
+ /// type Assoc: Duh;
  /// }
  ///
  /// struct Struct;
  ///
- /// impl Trait for Struct {
- /// type Assoc = i32;
+ /// impl<F: Duh> Trait for F {
+ /// type Assoc = F;
  /// }
  ///
  /// fn test() -> impl Trait<Assoc = impl Sized> {
- /// Struct
+ /// 42
  /// }
  /// ```
  ///

compiler/rustc_lint_defs/src/builtin.rs

@@ -605,7 +605,7 @@ declare_lint! {
  ///
  /// ### Example
  ///
- /// ```
+ /// ```rust
  /// #[warn(unused_tuple_struct_fields)]
  /// struct S(i32, i32, i32);
  /// let s = S(1, 2, 3);
@@ -1154,7 +1154,7 @@ declare_lint! {
  ///
  /// ### Example
  ///
- /// ```compile_fail
+ /// ```rust,compile_fail
  /// #[repr(packed)]
  /// pub struct Foo {
  /// field1: u64,
@@ -2548,7 +2548,7 @@ declare_lint! {
  ///
  /// ### Example
  ///
- /// ```compile_fail
+ /// ```rust,compile_fail
  /// # #![allow(unused)]
  /// enum E {
  /// A,
@@ -3918,7 +3918,7 @@ declare_lint! {
  ///
  /// ### Example
  ///
- /// ```
+ /// ```rust
  /// #![allow(test_unstable_lint)]
  /// ```
  ///

src/tools/lint-docs/src/lib.rs

@@ -37,10 +37,8 @@ impl Lint {
  }
 
  fn is_ignored(&self) -> bool {
- self.doc
- .iter()
- .filter(|line| line.starts_with("```rust"))
- .all(|line| line.contains(",ignore"))
+ let blocks: Vec<_> = self.doc.iter().filter(|line| line.starts_with("```rust")).collect();
+ !blocks.is_empty() && blocks.iter().all(|line| line.contains(",ignore"))
  }
 
  /// Checks the doc style of the lint.