diff --git a/CHANGELOG.md b/CHANGELOG.md
index da7042f4440..2b00fd962ca 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_attribute`]: https://rust-lang.github.io/rust-clippy/master/index.html#allow_attribute
[`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_attribute.rs b/clippy_lints/src/allow_attribute.rs
new file mode 100644
index 00000000000..2970d467f6f
--- /dev/null
+++ b/clippy_lints/src/allow_attribute.rs
@@ -0,0 +1,91 @@
+use ast::{AttrStyle, MetaItemKind};
+use clippy_utils::{diagnostics::span_lint_and_sugg, source::snippet};
+use rustc_ast as ast;
+use rustc_errors::Applicability;
+use rustc_lint::{LateContext, LateLintPass};
+use rustc_session::{declare_tool_lint, impl_lint_pass};
+use rustc_span::{symbol::Ident, BytePos};
+
+declare_clippy_lint! {
+ /// ### What it does
+ /// Detects uses of the `#[allow]` attribute and suggests to replace it with the new `#[expect]` attribute implemented by `#![feature(lint_reasons)]` ([RFC 2383](https://rust-lang.github.io/rfcs/2383-lint-reasons.html))
+ /// ### Why is this bad?
+ /// Using `#[allow]` isn't bad, but `#[expect]` may be preferred as it lints if the code **doesn't** produce a warning.
+ /// ### Example
+ /// ```rust
+ /// #[allow(unused_mut)]
+ /// fn foo() -> usize {
+ /// let mut a = Vec::new();
+ /// a.len()
+ ///}
+ /// ```
+ /// Use instead:
+ /// ```rust
+ /// #[expect(unused_mut)]
+ /// fn foo() -> usize {
+ /// let mut a = Vec::new();
+ /// a.len()
+ /// }
+ /// ```
+ #[clippy::version = "1.69.0"]
+ pub ALLOW_ATTRIBUTE,
+ restriction,
+ "`#[allow]` will not trigger if a warning isn't found. `#[expect]` triggers if there are no warnings."
+}
+
+pub struct AllowAttribute {
+ pub lint_reasons_active: bool,
+}
+
+impl_lint_pass!(AllowAttribute => [ALLOW_ATTRIBUTE]);
+
+impl LateLintPass<'_> for AllowAttribute {
+ // Separate each crate's features.
+ fn check_crate_post(&mut self, _: &LateContext<'_>) {
+ self.lint_reasons_active = false;
+ }
+ fn check_attribute(&mut self, cx: &LateContext<'_>, attr: &ast::Attribute) {
+ // Check inner attributes
+
+ if_chain! {
+ if let AttrStyle::Inner = attr.style;
+ if attr.ident()
+ .unwrap_or(Ident::with_dummy_span(sym!(empty))) // Will not trigger if doesn't have an ident.
+ .name == sym!(feature);
+ if let ast::AttrKind::Normal(normal) = &attr.kind;
+ if let Some(MetaItemKind::List(list)) = normal.item.meta_kind();
+ if list[0].ident().unwrap().name == sym!(lint_reasons);
+ then {
+ self.lint_reasons_active = true;
+ }
+ }
+
+ // Check outer attributes
+
+ if_chain! {
+ if let AttrStyle::Outer = attr.style;
+ if attr.ident()
+ .unwrap_or(Ident::with_dummy_span(sym!(empty))) // Will not trigger if doesn't have an ident.
+ .name == sym!(allow);
+ if self.lint_reasons_active;
+ then {
+ span_lint_and_sugg(
+ cx,
+ ALLOW_ATTRIBUTE,
+ attr.span,
+ "#[allow] attribute found",
+ "replace it with",
+ format!("#[expect{})]", snippet(
+ cx,
+ attr.ident().unwrap().span
+ .with_lo(
+ attr.ident().unwrap().span.hi() + BytePos(2) // Cut [(
+ )
+ .with_hi(
+ attr.meta().unwrap().span.hi() - BytePos(2) // Cut )]
+ )
+ , "...")), Applicability::MachineApplicable);
+ }
+ }
+ }
+}
diff --git a/clippy_lints/src/declared_lints.rs b/clippy_lints/src/declared_lints.rs
index cc6024b87cd..73f74d59f4a 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_attribute::ALLOW_ATTRIBUTE_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 491732be208..51da5d1ba49 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_attribute;
mod almost_complete_range;
mod approx_const;
mod as_conversions;
@@ -933,6 +934,11 @@ 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_attribute::AllowAttribute {
+ lint_reasons_active: false,
+ })
+ });
// add lints here, do not remove this comment, it's used in `new_lint`
}
diff --git a/tests/ui/allow_attribute.fixed b/tests/ui/allow_attribute.fixed
new file mode 100644
index 00000000000..5f445a0bd96
--- /dev/null
+++ b/tests/ui/allow_attribute.fixed
@@ -0,0 +1,18 @@
+// run-rustfix
+#![allow(unused)]
+#![warn(clippy::allow_attribute)]
+#![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;
diff --git a/tests/ui/allow_attribute.rs b/tests/ui/allow_attribute.rs
new file mode 100644
index 00000000000..36d2e3e27ab
--- /dev/null
+++ b/tests/ui/allow_attribute.rs
@@ -0,0 +1,18 @@
+// run-rustfix
+#![allow(unused)]
+#![warn(clippy::allow_attribute)]
+#![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;
diff --git a/tests/ui/allow_attribute.stderr b/tests/ui/allow_attribute.stderr
new file mode 100644
index 00000000000..6f90661577c
--- /dev/null
+++ b/tests/ui/allow_attribute.stderr
@@ -0,0 +1,10 @@
+error: #[allow] attribute found
+ --> $DIR/allow_attribute.rs:11:1
+ |
+LL | #[allow(dead_code)]
+ | ^^^^^^^^^^^^^^^^^^^ help: replace it with: `#[expect(dead_code)]`
+ |
+ = note: `-D clippy::allow-attribute` implied by `-D warnings`
+
+error: aborting due to previous error
+