diff --git a/CHANGELOG.md b/CHANGELOG.md
index da7042f4440..c090a844858 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4382,6 +4382,7 @@ Released 2018-09-13
<!-- begin autogenerated links to lint list -->
[`absurd_extreme_comparisons`]: https://rust-lang.github.io/rust-clippy/master/index.html#absurd_extreme_comparisons
[`alloc_instead_of_core`]: https://rust-lang.github.io/rust-clippy/master/index.html#alloc_instead_of_core
+[`allow_attributes`]: https://rust-lang.github.io/rust-clippy/master/index.html#allow_attributes
[`allow_attributes_without_reason`]: https://rust-lang.github.io/rust-clippy/master/index.html#allow_attributes_without_reason
[`almost_complete_letter_range`]: https://rust-lang.github.io/rust-clippy/master/index.html#almost_complete_letter_range
[`almost_complete_range`]: https://rust-lang.github.io/rust-clippy/master/index.html#almost_complete_range
diff --git a/clippy_lints/src/allow_attributes.rs b/clippy_lints/src/allow_attributes.rs
new file mode 100644
index 00000000000..15d46e954a9
--- /dev/null
+++ b/clippy_lints/src/allow_attributes.rs
@@ -0,0 +1,71 @@
+use ast::AttrStyle;
+use clippy_utils::diagnostics::span_lint_and_sugg;
+use rustc_ast as ast;
+use rustc_errors::Applicability;
+use rustc_lint::{LateContext, LateLintPass};
+use rustc_session::{declare_lint_pass, declare_tool_lint};
+
+declare_clippy_lint! {
+ /// Detects uses of the `#[allow]` attribute and suggests replacing it with
+ /// the `#[expect]` (See [RFC 2383](https://rust-lang.github.io/rfcs/2383-lint-reasons.html))
+ ///
+ /// The expect attribute is still unstable and requires the `lint_reasons`
+ /// on nightly. It can be enabled by adding `#![feature(lint_reasons)]` to
+ /// the crate root.
+ ///
+ /// This lint only warns outer attributes (`#[allow]`), as inner attributes
+ /// (`#![allow]`) are usually used to enable or disable lints on a global scale.
+ ///
+ /// ### Why is this bad?
+ ///
+ /// `#[expect]` attributes suppress the lint emission, but emit a warning, if
+ /// the expectation is unfulfilled. This can be useful to be notified when the
+ /// lint is no longer triggered.
+ ///
+ /// ### Example
+ /// ```rust,ignore
+ /// #[allow(unused_mut)]
+ /// fn foo() -> usize {
+ /// let mut a = Vec::new();
+ /// a.len()
+ /// }
+ /// ```
+ /// Use instead:
+ /// ```rust,ignore
+ /// #![feature(lint_reasons)]
+ /// #[expect(unused_mut)]
+ /// fn foo() -> usize {
+ /// let mut a = Vec::new();
+ /// a.len()
+ /// }
+ /// ```
+ #[clippy::version = "1.69.0"]
+ pub ALLOW_ATTRIBUTES,
+ restriction,
+ "`#[allow]` will not trigger if a warning isn't found. `#[expect]` triggers if there are no warnings."
+}
+
+declare_lint_pass!(AllowAttribute => [ALLOW_ATTRIBUTES]);
+
+impl LateLintPass<'_> for AllowAttribute {
+ // Separate each crate's features.
+ fn check_attribute(&mut self, cx: &LateContext<'_>, attr: &ast::Attribute) {
+ if_chain! {
+ if cx.tcx.features().lint_reasons;
+ if let AttrStyle::Outer = attr.style;
+ if let Some(ident) = attr.ident();
+ if ident.name == rustc_span::symbol::sym::allow;
+ then {
+ span_lint_and_sugg(
+ cx,
+ ALLOW_ATTRIBUTES,
+ ident.span,
+ "#[allow] attribute found",
+ "replace it with",
+ "expect".into(),
+ Applicability::MachineApplicable,
+ );
+ }
+ }
+ }
+}
diff --git a/clippy_lints/src/declared_lints.rs b/clippy_lints/src/declared_lints.rs
index cc6024b87cd..25f15973490 100644
--- a/clippy_lints/src/declared_lints.rs
+++ b/clippy_lints/src/declared_lints.rs
@@ -35,6 +35,7 @@ pub(crate) static LINTS: &[&crate::LintInfo] = &[
crate::utils::internal_lints::produce_ice::PRODUCE_ICE_INFO,
#[cfg(feature = "internal")]
crate::utils::internal_lints::unnecessary_def_path::UNNECESSARY_DEF_PATH_INFO,
+ crate::allow_attributes::ALLOW_ATTRIBUTES_INFO,
crate::almost_complete_range::ALMOST_COMPLETE_RANGE_INFO,
crate::approx_const::APPROX_CONSTANT_INFO,
crate::as_conversions::AS_CONVERSIONS_INFO,
diff --git a/clippy_lints/src/lib.rs b/clippy_lints/src/lib.rs
index bde84686cc1..4bb0e2ec96c 100644
--- a/clippy_lints/src/lib.rs
+++ b/clippy_lints/src/lib.rs
@@ -67,6 +67,7 @@ mod declared_lints;
mod renamed_lints;
// begin lints modules, do not remove this comment, it’s used in `update_lints`
+mod allow_attributes;
mod almost_complete_range;
mod approx_const;
mod as_conversions;
@@ -934,6 +935,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
store.register_late_pass(|_| Box::new(missing_assert_message::MissingAssertMessage));
store.register_early_pass(|| Box::new(redundant_async_block::RedundantAsyncBlock));
store.register_late_pass(|_| Box::new(let_with_type_underscore::UnderscoreTyped));
+ store.register_late_pass(|_| Box::new(allow_attributes::AllowAttribute));
// add lints here, do not remove this comment, it's used in `new_lint`
}
diff --git a/tests/ui/allow_attributes.fixed b/tests/ui/allow_attributes.fixed
new file mode 100644
index 00000000000..b8dd0619e6d
--- /dev/null
+++ b/tests/ui/allow_attributes.fixed
@@ -0,0 +1,25 @@
+// run-rustfix
+#![allow(unused)]
+#![warn(clippy::allow_attributes)]
+#![feature(lint_reasons)]
+
+fn main() {}
+
+// Using clippy::needless_borrow just as a placeholder, it isn't relevant.
+
+// Should lint
+#[expect(dead_code)]
+struct T1;
+
+struct T2; // Should not lint
+#[deny(clippy::needless_borrow)] // Should not lint
+struct T3;
+#[warn(clippy::needless_borrow)] // Should not lint
+struct T4;
+// `panic = "unwind"` should always be true
+#[cfg_attr(panic = "unwind", expect(dead_code))]
+struct CfgT;
+
+fn ignore_inner_attr() {
+ #![allow(unused)] // Should not lint
+}
diff --git a/tests/ui/allow_attributes.rs b/tests/ui/allow_attributes.rs
new file mode 100644
index 00000000000..295f560906a
--- /dev/null
+++ b/tests/ui/allow_attributes.rs
@@ -0,0 +1,25 @@
+// run-rustfix
+#![allow(unused)]
+#![warn(clippy::allow_attributes)]
+#![feature(lint_reasons)]
+
+fn main() {}
+
+// Using clippy::needless_borrow just as a placeholder, it isn't relevant.
+
+// Should lint
+#[allow(dead_code)]
+struct T1;
+
+struct T2; // Should not lint
+#[deny(clippy::needless_borrow)] // Should not lint
+struct T3;
+#[warn(clippy::needless_borrow)] // Should not lint
+struct T4;
+// `panic = "unwind"` should always be true
+#[cfg_attr(panic = "unwind", allow(dead_code))]
+struct CfgT;
+
+fn ignore_inner_attr() {
+ #![allow(unused)] // Should not lint
+}
diff --git a/tests/ui/allow_attributes.stderr b/tests/ui/allow_attributes.stderr
new file mode 100644
index 00000000000..681837e9ed7
--- /dev/null
+++ b/tests/ui/allow_attributes.stderr
@@ -0,0 +1,16 @@
+error: #[allow] attribute found
+ --> $DIR/allow_attributes.rs:11:3
+ |
+LL | #[allow(dead_code)]
+ | ^^^^^ help: replace it with: `expect`
+ |
+ = note: `-D clippy::allow-attributes` implied by `-D warnings`
+
+error: #[allow] attribute found
+ --> $DIR/allow_attributes.rs:20:30
+ |
+LL | #[cfg_attr(panic = "unwind", allow(dead_code))]
+ | ^^^^^ help: replace it with: `expect`
+
+error: aborting due to 2 previous errors
+