Stabilize lint_reasons in rustc (RFC 2383)

Author: xFrednet

compiler/rustc_feature/src/accepted.rs

@@ -188,6 +188,8 @@ declare_features! (
     (accepted, item_like_imports, "1.15.0", Some(35120), None),
     /// Allows `if/while p && let q = r && ...` chains.
     (accepted, let_chains, "1.64.0", Some(53667), None),
+    /// Allows using `reason` in lint attributes and the `#[expect(lint)]` lint check.
+    (accepted, lint_reasons, "1.64.0", Some(54503), None),
     /// Allows `break {expr}` with a value inside `loop`s.
     (accepted, loop_break_value, "1.19.0", Some(37339), None),
     /// Allows use of `?` as the Kleene "at most one" operator in macros.

compiler/rustc_feature/src/active.rs

@@ -428,8 +428,6 @@ declare_features! (
     (active, let_else, "1.56.0", Some(87335), None),
     /// Allows `#[link(..., cfg(..))]`.
     (active, link_cfg, "1.14.0", Some(37406), None),
-    /// Allows using `reason` in lint attributes and the `#[expect(lint)]` lint check.
-    (active, lint_reasons, "1.31.0", Some(54503), None),
     /// Give access to additional metadata about declarative macro meta-variables.
     (active, macro_metavar_expr, "1.61.0", Some(83527), None),
     /// Allows `#[marker]` on certain traits allowing overlapping implementations.

compiler/rustc_feature/src/builtin_attrs.rs

@@ -301,9 +301,8 @@ pub const BUILTIN_ATTRIBUTES: &[BuiltinAttribute] = &[
     ungated!(
         allow, Normal, template!(List: r#"lint1, lint2, ..., /*opt*/ reason = "...""#), DuplicatesOk
     ),
-    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
     ),
     ungated!(
         forbid, Normal, template!(List: r#"lint1, lint2, ..., /*opt*/ reason = "...""#), DuplicatesOk

compiler/rustc_lint/src/expect.rs

@@ -4,18 +4,13 @@ use rustc_hir::HirId;
 use rustc_middle::ty::query::Providers;
 use rustc_middle::{lint::LintExpectation, ty::TyCtxt};
 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.sess.features_untracked().enabled(sym::lint_reasons) {
-        return;
-    }
-
     let fulfilled_expectations = tcx.sess.diagnostic().steal_fulfilled_expectation_ids();
     let lint_expectations = &tcx.lint_levels(()).lint_expectations;
 

compiler/rustc_lint/src/levels.rs

@@ -17,7 +17,7 @@ use rustc_session::lint::{
     builtin::{self, FORBIDDEN_LINT_GROUPS, SINGLE_USE_LIFETIMES, UNFULFILLED_LINT_EXPECTATIONS},
     Level, Lint, LintExpectationId, LintId,
 };
-use rustc_session::parse::{add_feature_diagnostics, feature_err};
+use rustc_session::parse::add_feature_diagnostics;
 use rustc_session::Session;
 use rustc_span::symbol::{sym, Symbol};
 use rustc_span::{Span, DUMMY_SP};
@@ -306,15 +306,6 @@ impl<'s> LintLevelsBuilder<'s> {
                     ast::MetaItemKind::NameValue(ref name_value) => {
                         if item.path == sym::reason {
                             if let ast::LitKind::Str(rationale, _) = name_value.kind {
-                                if !self.sess.features_untracked().lint_reasons {
-                                    feature_err(
-                                        &self.sess.parse_sess,
-                                        sym::lint_reasons,
-                                        item.span,
-                                        "lint reasons are experimental",
-                                    )
-                                    .emit();
-                                }
                                 reason = Some(rationale);
                             } else {
                                 bad_attr(name_value.span)

compiler/rustc_lint_defs/src/builtin.rs

@@ -503,8 +503,6 @@ declare_lint! {
     /// ### Example
     ///
     /// ```rust
-    /// #![feature(lint_reasons)]
-    ///
     /// #[expect(unused_variables)]
     /// let x = 10;
     /// println!("{}", x);
@@ -530,8 +528,7 @@ declare_lint! {
     /// [#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/test/ui/empty/empty-attributes.rs

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

src/test/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: the lint level is defined here
-  --> $DIR/empty-attributes.rs:3:9
+  --> $DIR/empty-attributes.rs:1:9
    |
 LL | #![deny(unused_attributes)]
    |         ^^^^^^^^^^^^^^^^^
    = note: attribute `repr` with an empty list has no effect
 
 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