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Auto merge of #120924 - xFrednet:rfc-2383-stabilization-party, r=Urgau,blyxyas

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Let's `#[expect]` some lints: Stabilize `lint_reasons` (RFC 2383)

Let's give this another try! The [previous stabilization attempt](https://github.com/rust-lang/rust/pull/99063) was stalled by some unresolved questions. These have been discussed in a [lang team](https://github.com/rust-lang/lang-team/issues/191) meeting. The last open question, regarding the semantics of the `#[expect]` attribute was decided on in https://github.com/rust-lang/rust/issues/115980

I've just updated the [stabilization report](https://github.com/rust-lang/rust/issues/54503#issuecomment-1179563964) with the discussed questions and decisions. Luckily, the decision is inline with the current implementation.

This hopefully covers everything. Let's hope that the CI will be green like the spring.

fixes #115980
fixes #54503

---

r? `@wesleywiser`

Tacking Issue: https://github.com/rust-lang/rust/issues/54503
Stabilization Report: https://github.com/rust-lang/rust/issues/54503#issuecomment-1179563964
Documentation Update: https://github.com/rust-lang/reference/pull/1237

<!--
For Clippy:

changelog: [`allow_attributes`]: Is now available on stable, since the `lint_reasons` feature was stabilized
changelog: [`allow_attributes_without_reason`]: Is now available on stable, since the `lint_reasons` feature was stabilized
-->

---

Roses are red,
Violets are blue,
Let's expect lints,
With reason clues
This commit is contained in:
bors 2024-06-26 16:38:30 +00:00
commit 4bc39f028d
170 changed files with 917 additions and 870 deletions
Download patch file Download diff file Expand all files Collapse all files

2
compiler/rustc_builtin_macros/src/lib.rs
View file

@ -5,6 +5,7 @@
#![allow(internal_features)]
#![allow(rustc::diagnostic_outside_of_impl)]
#![allow(rustc::untranslatable_diagnostic)]
#![cfg_attr(bootstrap, feature(lint_reasons))]
#![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
#![doc(rust_logo)]
#![feature(assert_matches)]
@ -12,7 +13,6 @@
#![feature(decl_macro)]
#![feature(if_let_guard)]
#![feature(let_chains)]
#![feature(lint_reasons)]
#![feature(proc_macro_internals)]
#![feature(proc_macro_quote)]
#![feature(rustdoc_internals)]

2
compiler/rustc_data_structures/src/lib.rs
View file

@ -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)]

7
compiler/rustc_errors/src/json.rs
View file

@ -135,7 +135,12 @@ impl Emitter for JsonEmitter {
let data: Vec<FutureBreakageItem<'_>> = diags
.into_iter()
.map(|mut diag| {
if diag.level == crate::Level::Allow {
// Allowed or expected lints don't normally (by definition) emit a lint
// but future incompat lints are special and are emitted anyway.
//
// So to avoid ICEs and confused users we "upgrade" the lint level for
// those `FutureBreakageItem` to warn.
if matches!(diag.level, crate::Level::Allow | crate::Level::Expect(..)) {
diag.level = crate::Level::Warning;
}
FutureBreakageItem {

2
compiler/rustc_feature/src/accepted.rs
View file

@ -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.

6
compiler/rustc_feature/src/builtin_attrs.rs
View file

@ -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 = "...""#),

2
compiler/rustc_feature/src/unstable.rs
View file

@ -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.

5
compiler/rustc_lint/src/expect.rs
View file

@ -3,7 +3,6 @@ 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) {
@ -11,10 +10,6 @@ pub(crate) fn provide(providers: &mut 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();

10
compiler/rustc_lint/src/levels.rs
View file

@ -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 {

26
compiler/rustc_lint_defs/src/builtin.rs
View file

@ -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 detects when 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! {