RFC 2383: Stabilize lint_reasons 🎉

Author: xFrednet

compiler/rustc_builtin_macros/src/lib.rs

@@ -12,7 +12,7 @@
 #![feature(decl_macro)]
 #![feature(if_let_guard)]
 #![feature(let_chains)]
-#![feature(lint_reasons)]
+#![cfg_attr(bootstrap, feature(lint_reasons))]
 #![feature(proc_macro_internals)]
 #![feature(proc_macro_quote)]
 #![feature(rustdoc_internals)]

compiler/rustc_data_structures/src/lib.rs

@@ -10,6 +10,7 @@
 #![allow(internal_features)]
 #![allow(rustc::default_hash_types)]
 #![allow(rustc::potential_query_instability)]
+#![cfg_attr(bootstrap, feature(lint_reasons))]
 #![cfg_attr(not(parallel_compiler), feature(cell_leak))]
 #![deny(unsafe_op_in_unsafe_fn)]
 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
@@ -24,7 +25,6 @@
 #![feature(extend_one)]
 #![feature(hash_raw_entry)]
 #![feature(hasher_prefixfree_extras)]
-#![feature(lint_reasons)]
 #![feature(macro_metavar_expr)]
 #![feature(map_try_insert)]
 #![feature(min_specialization)]

compiler/rustc_feature/src/accepted.rs

@@ -232,6 +232,8 @@ declare_features! (
     (accepted, label_break_value, "1.65.0", Some(48594)),
     /// Allows `let...else` statements.
     (accepted, let_else, "1.65.0", Some(87335)),
+    /// Allows using `reason` in lint attributes and the `#[expect(lint)]` lint check.
+    (accepted, lint_reasons, "CURRENT_RUSTC_VERSION", Some(54503)),
     /// Allows `break {expr}` with a value inside `loop`s.
     (accepted, loop_break_value, "1.19.0", Some(37339)),
     /// Allows use of `?` as the Kleene "at most one" operator in macros.

compiler/rustc_feature/src/builtin_attrs.rs

@@ -369,9 +369,9 @@ pub const BUILTIN_ATTRIBUTES: &[BuiltinAttribute] = &[
         allow, Normal, template!(List: r#"lint1, lint2, ..., /*opt*/ reason = "...""#),
         DuplicatesOk, EncodeCrossCrate::No,
     ),
-    gated!(
-        expect, Normal, template!(List: r#"lint1, lint2, ..., /*opt*/ reason = "...""#), DuplicatesOk,
-        EncodeCrossCrate::No, lint_reasons, experimental!(expect)
+    ungated!(
+        expect, Normal, template!(List: r#"lint1, lint2, ..., /*opt*/ reason = "...""#),
+        DuplicatesOk, EncodeCrossCrate::No,
     ),
     ungated!(
         forbid, Normal, template!(List: r#"lint1, lint2, ..., /*opt*/ reason = "...""#),

compiler/rustc_feature/src/unstable.rs

@@ -512,8 +512,6 @@ declare_features! (
     /// Allows using `#[link(kind = "link-arg", name = "...")]`
     /// to pass custom arguments to the linker.
     (unstable, link_arg_attribute, "1.76.0", Some(99427)),
-    /// Allows using `reason` in lint attributes and the `#[expect(lint)]` lint check.
-    (unstable, lint_reasons, "1.31.0", Some(54503)),
     /// Give access to additional metadata about declarative macro meta-variables.
     (unstable, macro_metavar_expr, "1.61.0", Some(83527)),
     /// Provides a way to concatenate identifiers using metavariable expressions.

compiler/rustc_lint/src/expect.rs

@@ -3,18 +3,13 @@ use rustc_middle::query::Providers;
 use rustc_middle::ty::TyCtxt;
 use rustc_session::lint::builtin::UNFULFILLED_LINT_EXPECTATIONS;
 use rustc_session::lint::LintExpectationId;
-use rustc_span::symbol::sym;
 use rustc_span::Symbol;
 
 pub(crate) fn provide(providers: &mut Providers) {
     *providers = Providers { check_expectations, ..*providers };
 }
 
 fn check_expectations(tcx: TyCtxt<'_>, tool_filter: Option<Symbol>) {
-    if !tcx.features().active(sym::lint_reasons) {
-        return;
-    }
-
     let lint_expectations = tcx.lint_expectations(());
     let fulfilled_expectations = tcx.dcx().steal_fulfilled_expectation_ids();
 

compiler/rustc_lint/src/levels.rs

@@ -37,7 +37,6 @@ use rustc_session::lint::{
     },
     Level, Lint, LintExpectationId, LintId,
 };
-use rustc_session::parse::feature_err;
 use rustc_session::Session;
 use rustc_span::symbol::{sym, Symbol};
 use rustc_span::{Span, DUMMY_SP};
@@ -788,15 +787,6 @@ impl<'s, P: LintLevelsProvider> LintLevelsBuilder<'s, P> {
                     ast::MetaItemKind::NameValue(ref name_value) => {
                         if item.path == sym::reason {
                             if let ast::LitKind::Str(rationale, _) = name_value.kind {
-                                if !self.features.lint_reasons {
-                                    feature_err(
-                                        &self.sess,
-                                        sym::lint_reasons,
-                                        item.span,
-                                        "lint reasons are experimental",
-                                    )
-                                    .emit();
-                                }
                                 reason = Some(rationale);
                             } else {
                                 sess.dcx().emit_err(MalformedAttribute {

compiler/rustc_lint_defs/src/builtin.rs

@@ -608,13 +608,13 @@ declare_lint! {
 }
 
 declare_lint! {
-    /// The `unfulfilled_lint_expectations` lint detects lint trigger expectations
-    /// that have not been fulfilled.
+    /// The `unfulfilled_lint_expectations` lint warns if a lint expectation is
+    /// unfulfilled.
     ///
     /// ### Example
     ///
     /// ```rust
-    /// #![feature(lint_reasons)]
+    /// #![cfg_attr(bootstrap, feature(lint_reasons))]
     ///
     /// #[expect(unused_variables)]
     /// let x = 10;
@@ -625,24 +625,14 @@ declare_lint! {
     ///
     /// ### Explanation
     ///
-    /// It was expected that the marked code would emit a lint. This expectation
-    /// has not been fulfilled.
+    /// The `#[expect]` attribute can be used to create a lint expectation. The
+    /// expectation is fulfilled, if a `#[warn]` attribute at the same location
+    /// would result in a lint emission. If the expectation is unfulfilled,
+    /// because no lint was emitted, this lint will be emitted on the attribute.
     ///
-    /// The `expect` attribute can be removed if this is intended behavior otherwise
-    /// it should be investigated why the expected lint is no longer issued.
-    ///
-    /// In rare cases, the expectation might be emitted at a different location than
-    /// shown in the shown code snippet. In most cases, the `#[expect]` attribute
-    /// works when added to the outer scope. A few lints can only be expected
-    /// on a crate level.
-    ///
-    /// Part of RFC 2383. The progress is being tracked in [#54503]
-    ///
-    /// [#54503]: https://github.com/rust-lang/rust/issues/54503
     pub UNFULFILLED_LINT_EXPECTATIONS,
     Warn,
-    "unfulfilled lint expectation",
-    @feature_gate = rustc_span::sym::lint_reasons;
+    "unfulfilled lint expectation"
 }
 
 declare_lint! {

src/tools/rust-analyzer/crates/hir-expand/src/inert_attr_macro.rs

@@ -142,9 +142,9 @@ pub const INERT_ATTRIBUTES: &[BuiltinAttribute] = &[
         allow, Normal, template!(List: r#"lint1, lint2, ..., /*opt*/ reason = "...""#),
         DuplicatesOk, @only_local: true,
     ),
-    gated!(
-        expect, Normal, template!(List: r#"lint1, lint2, ..., /*opt*/ reason = "...""#), DuplicatesOk,
-        lint_reasons, experimental!(expect)
+    ungated!(
+        expect, Normal, template!(List: r#"lint1, lint2, ..., /*opt*/ reason = "...""#),
+        DuplicatesOk, @only_local: true,
     ),
     ungated!(
         forbid, Normal, template!(List: r#"lint1, lint2, ..., /*opt*/ reason = "...""#),

tests/rustdoc-ui/lints/expect-tool-lint-rfc-2383.rs

@@ -1,5 +1,4 @@
 //@ check-pass
-#![feature(lint_reasons)]
 
 //! This file tests the `#[expect]` attribute implementation for tool lints. The same
 //! file is used to test clippy and rustdoc. Any changes to this file should be synced

tests/ui/async-await/in-trait/async-example-desugared-extra.rs

@@ -1,8 +1,6 @@
 //@ check-pass
 //@ edition: 2021
 
-#![feature(lint_reasons)]
-
 use std::future::Future;
 use std::pin::Pin;
 use std::task::Poll;

tests/ui/cfg/diagnostics-not-a-def.rs

@@ -1,5 +1,3 @@
-#![feature(lint_reasons)]
-
 pub mod inner {
     #[expect(unexpected_cfgs)]
     pub fn i_am_here() {

tests/ui/cfg/diagnostics-not-a-def.stderr

@@ -1,5 +1,5 @@
 error[E0425]: cannot find function `i_am_not` in module `inner`
-  --> $DIR/diagnostics-not-a-def.rs:14:12
+  --> $DIR/diagnostics-not-a-def.rs:12:12
    |
 LL |     inner::i_am_not();
    |            ^^^^^^^^ not found in `inner`

tests/ui/empty/empty-attributes.rs

@@ -1,5 +1,3 @@
-#![feature(lint_reasons)]
-
 #![deny(unused_attributes)]
 #![allow()] //~ ERROR unused attribute
 #![expect()] //~ ERROR unused attribute

tests/ui/empty/empty-attributes.stderr

@@ -1,66 +1,66 @@
 error: unused attribute
-  --> $DIR/empty-attributes.rs:11:1
+  --> $DIR/empty-attributes.rs:9:1
    |
 LL | #[repr()]
    | ^^^^^^^^^ help: remove this attribute
    |
    = note: attribute `repr` with an empty list has no effect
 note: the lint level is defined here
-  --> $DIR/empty-attributes.rs:3:9
+  --> $DIR/empty-attributes.rs:1:9
    |
 LL | #![deny(unused_attributes)]
    |         ^^^^^^^^^^^^^^^^^
 
 error: unused attribute
-  --> $DIR/empty-attributes.rs:14:1
+  --> $DIR/empty-attributes.rs:12:1
    |
 LL | #[target_feature()]
    | ^^^^^^^^^^^^^^^^^^^ help: remove this attribute
    |
    = note: attribute `target_feature` with an empty list has no effect
 
 error: unused attribute
-  --> $DIR/empty-attributes.rs:4:1
+  --> $DIR/empty-attributes.rs:2:1
    |
 LL | #![allow()]
    | ^^^^^^^^^^^ help: remove this attribute
    |
    = note: attribute `allow` with an empty list has no effect
 
 error: unused attribute
-  --> $DIR/empty-attributes.rs:5:1
+  --> $DIR/empty-attributes.rs:3:1
    |
 LL | #![expect()]
    | ^^^^^^^^^^^^ help: remove this attribute
    |
    = note: attribute `expect` with an empty list has no effect
 
 error: unused attribute
-  --> $DIR/empty-attributes.rs:6:1
+  --> $DIR/empty-attributes.rs:4:1
    |
 LL | #![warn()]
    | ^^^^^^^^^^ help: remove this attribute
    |
    = note: attribute `warn` with an empty list has no effect
 
 error: unused attribute
-  --> $DIR/empty-attributes.rs:7:1
+  --> $DIR/empty-attributes.rs:5:1
    |
 LL | #![deny()]
    | ^^^^^^^^^^ help: remove this attribute
    |
    = note: attribute `deny` with an empty list has no effect
 
 error: unused attribute
-  --> $DIR/empty-attributes.rs:8:1
+  --> $DIR/empty-attributes.rs:6:1
    |
 LL | #![forbid()]
    | ^^^^^^^^^^^^ help: remove this attribute
    |
    = note: attribute `forbid` with an empty list has no effect
 
 error: unused attribute
-  --> $DIR/empty-attributes.rs:9:1
+  --> $DIR/empty-attributes.rs:7:1
    |
 LL | #![feature()]
    | ^^^^^^^^^^^^^ help: remove this attribute

tests/ui/error-codes/E0602.stderr

@@ -13,6 +13,11 @@ warning[E0602]: unknown lint: `bogus`
    = note: requested on the command line with `-D bogus`
    = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 
-warning: 3 warnings emitted
+warning[E0602]: unknown lint: `bogus`
+   |
+   = note: requested on the command line with `-D bogus`
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
+
+warning: 4 warnings emitted
 
 For more information about this error, try `rustc --explain E0602`.

tests/ui/feature-gates/feature-gate-lint-reasons.rs

@@ -1,5 +1,3 @@
-#![feature(lint_reasons)]
-
 use std::ops::Deref;
 
 pub trait Foo {

tests/ui/feature-gates/feature-gate-lint-reasons.stderr

@@ -1,7 +1,5 @@
 //@ check-pass
 
-#![feature(lint_reasons)]
-
 pub struct Wrapper<T>(T);
 
 pub trait Foo {

tests/ui/impl-trait/in-trait/auxiliary/rpitit.rs

@@ -5,7 +5,7 @@ LL |     let _: &dyn rpitit::Foo = todo!();
    |            ^^^^^^^^^^^^^^^^ `Foo` cannot be made into an object
    |
 note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
-  --> $DIR/auxiliary/rpitit.rs:6:21
+  --> $DIR/auxiliary/rpitit.rs:4:21
    |
 LL |     fn bar(self) -> impl Deref<Target = impl Sized>;
    |                     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait cannot be made into an object because method `bar` references an `impl Trait` type in its return type

tests/ui/impl-trait/in-trait/deep-match-works.rs

@@ -1,8 +1,6 @@
 //@ check-pass
 //@ aux-build: rpitit.rs
 
-#![feature(lint_reasons)]
-
 extern crate rpitit;
 
 use rpitit::{Foo, Foreign};

tests/ui/impl-trait/in-trait/foreign-dyn-error.stderr

@@ -1,13 +1,13 @@
 warning: impl trait in impl method signature does not match trait method signature
-  --> $DIR/foreign.rs:23:21
+  --> $DIR/foreign.rs:21:21
    |
 LL |     fn bar(self) -> Arc<String> {
    |                     ^^^^^^^^^^^
    |
    = note: add `#[allow(refining_impl_trait)]` if it is intended for this to be part of the public API of this crate
    = note: we are soliciting feedback, see issue #121718 <https://github.com/rust-lang/rust/issues/121718> for more information
 note: the lint level is defined here
-  --> $DIR/foreign.rs:22:12
+  --> $DIR/foreign.rs:20:12
    |
 LL |     #[warn(refining_impl_trait)]
    |            ^^^^^^^^^^^^^^^^^^^
@@ -18,15 +18,15 @@ LL |     fn bar(self) -> impl Deref<Target = impl Sized> {
    |                     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 warning: impl trait in impl method signature does not match trait method signature
-  --> $DIR/foreign.rs:33:21
+  --> $DIR/foreign.rs:31:21
    |
 LL |     fn bar(self) -> Arc<String> {
    |                     ^^^^^^^^^^^
    |
    = note: add `#[allow(refining_impl_trait)]` if it is intended for this to be part of the public API of this crate
    = note: we are soliciting feedback, see issue #121718 <https://github.com/rust-lang/rust/issues/121718> for more information
 note: the lint level is defined here
-  --> $DIR/foreign.rs:31:12
+  --> $DIR/foreign.rs:29:12
    |
 LL |     #[warn(refining_impl_trait)]
    |            ^^^^^^^^^^^^^^^^^^^

tests/ui/impl-trait/in-trait/foreign.rs

@@ -1,7 +1,5 @@
 //@ check-pass
 
-#![feature(lint_reasons)]
-
 use std::fmt::Display;
 use std::ops::Deref;
 

tests/ui/impl-trait/in-trait/foreign.stderr

@@ -1,7 +1,5 @@
 //@ check-pass
 
-#![feature(lint_reasons)]
-
 pub trait Foo {
     fn f() -> Box<impl Sized>;
 }