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Use attribute parser for deprecated attribute checking #160459

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3 changes: 2 additions & 1 deletion compiler/rustc_ast/src/visit.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -15,13 +15,14 @@

pub use rustc_ast_ir::visit::VisitorResult;
pub use rustc_ast_ir::{try_visit, visit_opt, walk_list, walk_visitable_list};
use rustc_macros::StableHash;
use rustc_span::{Ident, Span, Spanned, Symbol};
use thin_vec::ThinVec;

use crate::ast::*;
use crate::tokenstream::DelimSpan;

#[derive(Copy, Clone, Debug, PartialEq)]
#[derive(Copy, Clone, Debug, PartialEq, Eq, StableHash)]
pub enum AssocCtxt {
Trait,
Impl { of_trait: bool },
Expand Down
44 changes: 22 additions & 22 deletions compiler/rustc_attr_ir/src/lang_items.rs
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Expand Up @@ -14,7 +14,7 @@ use rustc_span::def_id::DefId;
use rustc_span::{Symbol, kw, sym};

use crate::PrintAttribute;
use crate::target::{MethodKind, Target};
use crate::target::{AssocCtxt, MethodKind, Target};

/// All of the lang items, defined or not.
/// Defined lang items can come from the current crate or its dependencies.
Expand Down Expand Up @@ -161,8 +161,8 @@ language_item_table! {
MetaSized, sym::meta_sized, meta_sized_trait, Target::Trait, GenericRequirement::Exact(0);
PointeeSized, sym::pointee_sized, pointee_sized_trait, Target::Trait, GenericRequirement::Exact(0);
Unsize, sym::unsize, unsize_trait, Target::Trait, GenericRequirement::Minimum(1);
AlignOf, sym::mem_align_const, align_const, Target::AssocConst, GenericRequirement::Exact(0);
SizeOf, sym::mem_size_const, size_const, Target::AssocConst, GenericRequirement::Exact(0);
AlignOf, sym::mem_align_const, align_const, Target::AssocConst(AssocCtxt::Trait), GenericRequirement::Exact(0);
SizeOf, sym::mem_size_const, size_const, Target::AssocConst(AssocCtxt::Trait), GenericRequirement::Exact(0);
OffsetOf, sym::offset_of, offset_of, Target::Fn, GenericRequirement::Exact(1);
/// Trait injected by `#[derive(PartialEq)]`, (i.e. "Partial EQ").
StructuralPeq, sym::structural_peq, structural_peq_trait, Target::Trait, GenericRequirement::None;
Expand All @@ -174,10 +174,10 @@ language_item_table! {
Sync, sym::sync, sync_trait, Target::Trait, GenericRequirement::Exact(0);
DiscriminantKind, sym::discriminant_kind, discriminant_kind_trait, Target::Trait, GenericRequirement::None;
/// The associated item of the `DiscriminantKind` trait.
Discriminant, sym::discriminant_type, discriminant_type, Target::AssocTy, GenericRequirement::None;
Discriminant, sym::discriminant_type, discriminant_type, Target::AssocTy(AssocCtxt::Trait), GenericRequirement::None;

PointeeTrait, sym::pointee_trait, pointee_trait, Target::Trait, GenericRequirement::None;
Metadata, sym::metadata_type, metadata_type, Target::AssocTy, GenericRequirement::None;
Metadata, sym::metadata_type, metadata_type, Target::AssocTy(AssocCtxt::Trait), GenericRequirement::None;
DynMetadata, sym::dyn_metadata, dyn_metadata, Target::Struct, GenericRequirement::None;

Freeze, sym::freeze, freeze_trait, Target::Trait, GenericRequirement::Exact(0);
Expand Down Expand Up @@ -237,9 +237,9 @@ language_item_table! {
Deref, sym::deref, deref_trait, Target::Trait, GenericRequirement::Exact(0);
DerefMut, sym::deref_mut, deref_mut_trait, Target::Trait, GenericRequirement::Exact(0);
DerefPure, sym::deref_pure, deref_pure_trait, Target::Trait, GenericRequirement::Exact(0);
DerefTarget, sym::deref_target, deref_target, Target::AssocTy, GenericRequirement::None;
DerefTarget, sym::deref_target, deref_target, Target::AssocTy(AssocCtxt::Trait), GenericRequirement::None;
Receiver, sym::receiver, receiver_trait, Target::Trait, GenericRequirement::None;
ReceiverTarget, sym::receiver_target, receiver_target, Target::AssocTy, GenericRequirement::None;
ReceiverTarget, sym::receiver_target, receiver_target, Target::AssocTy(AssocCtxt::Trait), GenericRequirement::None;
LegacyReceiver, sym::legacy_receiver, legacy_receiver_trait, Target::Trait, GenericRequirement::None;

Fn, kw::Fn, fn_trait, Target::Trait, GenericRequirement::Exact(1);
Expand All @@ -249,24 +249,24 @@ language_item_table! {
AsyncFn, sym::async_fn, async_fn_trait, Target::Trait, GenericRequirement::Exact(1);
AsyncFnMut, sym::async_fn_mut, async_fn_mut_trait, Target::Trait, GenericRequirement::Exact(1);
AsyncFnOnce, sym::async_fn_once, async_fn_once_trait, Target::Trait, GenericRequirement::Exact(1);
AsyncFnOnceOutput, sym::async_fn_once_output, async_fn_once_output, Target::AssocTy, GenericRequirement::Exact(1);
CallOnceFuture, sym::call_once_future, call_once_future, Target::AssocTy, GenericRequirement::Exact(1);
CallRefFuture, sym::call_ref_future, call_ref_future, Target::AssocTy, GenericRequirement::Exact(2);
AsyncFnOnceOutput, sym::async_fn_once_output, async_fn_once_output, Target::AssocTy(AssocCtxt::Trait), GenericRequirement::Exact(1);
CallOnceFuture, sym::call_once_future, call_once_future, Target::AssocTy(AssocCtxt::Trait), GenericRequirement::Exact(1);
CallRefFuture, sym::call_ref_future, call_ref_future, Target::AssocTy(AssocCtxt::Trait), GenericRequirement::Exact(2);
AsyncFnKindHelper, sym::async_fn_kind_helper, async_fn_kind_helper, Target::Trait, GenericRequirement::Exact(1);
AsyncFnKindUpvars, sym::async_fn_kind_upvars, async_fn_kind_upvars, Target::AssocTy, GenericRequirement::Exact(5);
AsyncFnKindUpvars, sym::async_fn_kind_upvars, async_fn_kind_upvars, Target::AssocTy(AssocCtxt::Trait), GenericRequirement::Exact(5);

FnOnceOutput, sym::fn_once_output, fn_once_output, Target::AssocTy, GenericRequirement::None;
FnOnceOutput, sym::fn_once_output, fn_once_output, Target::AssocTy(AssocCtxt::Trait), GenericRequirement::None;

Iterator, sym::iterator, iterator_trait, Target::Trait, GenericRequirement::Exact(0);
FusedIterator, sym::fused_iterator, fused_iterator_trait, Target::Trait, GenericRequirement::Exact(0);
Future, sym::future_trait, future_trait, Target::Trait, GenericRequirement::Exact(0);
FutureOutput, sym::future_output, future_output, Target::AssocTy, GenericRequirement::Exact(0);
FutureOutput, sym::future_output, future_output, Target::AssocTy(AssocCtxt::Trait), GenericRequirement::Exact(0);
AsyncIterator, sym::async_iterator, async_iterator_trait, Target::Trait, GenericRequirement::Exact(0);

CoroutineState, sym::coroutine_state, coroutine_state, Target::Enum, GenericRequirement::None;
Coroutine, sym::coroutine, coroutine_trait, Target::Trait, GenericRequirement::Exact(1);
CoroutineReturn, sym::coroutine_return, coroutine_return, Target::AssocTy, GenericRequirement::Exact(1);
CoroutineYield, sym::coroutine_yield, coroutine_yield, Target::AssocTy, GenericRequirement::Exact(1);
CoroutineReturn, sym::coroutine_return, coroutine_return, Target::AssocTy(AssocCtxt::Trait), GenericRequirement::Exact(1);
CoroutineYield, sym::coroutine_yield, coroutine_yield, Target::AssocTy(AssocCtxt::Trait), GenericRequirement::Exact(1);
CoroutineResume, sym::coroutine_resume, coroutine_resume, Target::Method(MethodKind::Trait { body: false }), GenericRequirement::None;

Unpin, sym::unpin, unpin_trait, Target::Trait, GenericRequirement::None;
Expand Down Expand Up @@ -384,8 +384,8 @@ language_item_table! {
PollPending, sym::Pending, poll_pending_variant, Target::Variant, GenericRequirement::None;

AsyncGenReady, sym::AsyncGenReady, async_gen_ready, Target::Method(MethodKind::Inherent), GenericRequirement::Exact(1);
AsyncGenPending, sym::AsyncGenPending, async_gen_pending, Target::AssocConst, GenericRequirement::Exact(1);
AsyncGenFinished, sym::AsyncGenFinished, async_gen_finished, Target::AssocConst, GenericRequirement::Exact(1);
AsyncGenPending, sym::AsyncGenPending, async_gen_pending, Target::AssocConst(AssocCtxt::Impl { of_trait: false }), GenericRequirement::Exact(1);
AsyncGenFinished, sym::AsyncGenFinished, async_gen_finished, Target::AssocConst(AssocCtxt::Impl { of_trait: false }), GenericRequirement::Exact(1);

// FIXME(swatinem): the following lang items are used for async lowering and
// should become obsolete eventually.
Expand Down Expand Up @@ -421,8 +421,8 @@ language_item_table! {
Range, sym::Range, range_struct, Target::Struct, GenericRequirement::None;
RangeToInclusive, sym::RangeToInclusive, range_to_inclusive_struct, Target::Struct, GenericRequirement::None;
RangeTo, sym::RangeTo, range_to_struct, Target::Struct, GenericRequirement::None;
RangeMax, sym::RangeMax, range_max, Target::AssocConst, GenericRequirement::Exact(0);
RangeMin, sym::RangeMin, range_min, Target::AssocConst, GenericRequirement::Exact(0);
RangeMax, sym::RangeMax, range_max, Target::AssocConst(AssocCtxt::Trait), GenericRequirement::Exact(0);
RangeMin, sym::RangeMin, range_min, Target::AssocConst(AssocCtxt::Trait), GenericRequirement::Exact(0);
RangeSub, sym::RangeSub, range_sub, Target::Method(MethodKind::Trait { body: false }), GenericRequirement::Exact(0);

// `new_range` types that are `Copy + IntoIterator`
Expand Down Expand Up @@ -453,9 +453,9 @@ language_item_table! {
// Field representing types.
FieldRepresentingType, sym::field_representing_type, field_representing_type, Target::Struct, GenericRequirement::Exact(3);
Field, sym::field, field, Target::Trait, GenericRequirement::Exact(0);
FieldBase, sym::field_base, field_base, Target::AssocTy, GenericRequirement::Exact(0);
FieldType, sym::field_type, field_type, Target::AssocTy, GenericRequirement::Exact(0);
FieldOffset, sym::field_offset, field_offset, Target::AssocConst, GenericRequirement::Exact(0);
FieldBase, sym::field_base, field_base, Target::AssocTy(AssocCtxt::Trait), GenericRequirement::Exact(0);
FieldType, sym::field_type, field_type, Target::AssocTy(AssocCtxt::Trait), GenericRequirement::Exact(0);
FieldOffset, sym::field_offset, field_offset, Target::AssocConst(AssocCtxt::Trait), GenericRequirement::Exact(0);

// Used to fallback `{float}` to `f32` when `f32: From<{float}>`
From, sym::From, from_trait, Target::Trait, GenericRequirement::Exact(1);
Expand Down
20 changes: 10 additions & 10 deletions compiler/rustc_attr_ir/src/target.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -2,7 +2,7 @@

use std::fmt::{self, Display};

use rustc_ast::visit::AssocCtxt;
pub use rustc_ast::visit::AssocCtxt;
use rustc_ast::{AssocItemKind, ForeignItemKind, ast};
use rustc_macros::StableHash;

Expand Down Expand Up @@ -49,9 +49,9 @@ pub enum Target {
Expression,
Statement,
Arm,
AssocConst,
AssocConst(AssocCtxt),
Method(MethodKind),
AssocTy,
AssocTy(AssocCtxt),
ForeignFn,
ForeignStatic,
ForeignTy,
Expand Down Expand Up @@ -81,7 +81,7 @@ rustc_error_messages::into_diag_arg_using_display!(Target);
impl Target {
pub fn is_associated_item(self) -> bool {
match self {
Target::AssocConst | Target::AssocTy | Target::Method(_) => true,
Target::AssocConst(_) | Target::AssocTy(_) | Target::Method(_) => true,
Target::ExternCrate
| Target::Use
| Target::Static
Expand Down Expand Up @@ -157,7 +157,7 @@ impl Target {

pub fn from_assoc_item_kind(kind: &ast::AssocItemKind, assoc_ctxt: AssocCtxt) -> Target {
match kind {
AssocItemKind::Const(_) => Target::AssocConst,
AssocItemKind::Const(_) => Target::AssocConst(assoc_ctxt),
AssocItemKind::Fn(f) => Target::Method(match assoc_ctxt {
AssocCtxt::Trait => MethodKind::Trait { body: f.body.is_some() },
AssocCtxt::Impl { of_trait, .. } => {
Expand All @@ -168,7 +168,7 @@ impl Target {
}
}
}),
AssocItemKind::Type(_) => Target::AssocTy,
AssocItemKind::Type(_) => Target::AssocTy(assoc_ctxt),
AssocItemKind::Delegation(_) => Target::Delegation { mac: false },
AssocItemKind::DelegationMac(_) => Target::Delegation { mac: true },
AssocItemKind::MacCall(_) => Target::MacroCall,
Expand Down Expand Up @@ -210,14 +210,14 @@ impl Target {
Target::Expression => "expression",
Target::Statement => "statement",
Target::Arm => "match arm",
Target::AssocConst => "associated const",
Target::AssocConst(_) => "associated const",
Target::Method(kind) => match kind {
MethodKind::Inherent => "inherent method",
MethodKind::Trait { body: false } => "required trait method",
MethodKind::Trait { body: true } => "provided trait method",
MethodKind::TraitImpl => "trait method in an impl block",
},
Target::AssocTy => "associated type",
Target::AssocTy(_) => "associated type",
Target::ForeignFn => "foreign function",
Target::ForeignStatic => "foreign static item",
Target::ForeignTy => "foreign type",
Expand Down Expand Up @@ -265,14 +265,14 @@ impl Target {
Target::Expression => "expressions",
Target::Statement => "statements",
Target::Arm => "match arms",
Target::AssocConst => "associated consts",
Target::AssocConst(_) => "associated consts",
Target::Method(kind) => match kind {
MethodKind::Inherent => "inherent methods",
MethodKind::Trait { body: false } => "required trait methods",
MethodKind::Trait { body: true } => "provided trait methods",
MethodKind::TraitImpl => "trait methods in impl blocks",
},
Target::AssocTy => "associated types",
Target::AssocTy(_) => "associated types",
Target::ForeignFn => "foreign functions",
Target::ForeignStatic => "foreign statics",
Target::ForeignTy => "foreign types",
Expand Down
31 changes: 28 additions & 3 deletions compiler/rustc_attr_parsing/src/attributes/deprecation.rs
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@@ -1,10 +1,15 @@
use rustc_ast::LitKind;
use rustc_attr_ir::{DeprecatedSince, Deprecation, RustcVersion, VERSION_PLACEHOLDER};
use rustc_feature::AttributeStability;
use rustc_session::lint::builtin::UNUSED_ATTRIBUTES;

use super::prelude::*;
use super::util::parse_version;
use crate::diagnostics::{DeprecatedItemSuggestion, InvalidSince, MissingNote, MissingSince};
use crate::diagnostics::{
DeprecatedAnnotationHasNoEffect, DeprecatedItemSuggestion, InvalidSince, MissingNote,
MissingSince,
};
use crate::target_checking::Policy::AllowSilent;

fn get(
cx: &mut AcceptContext<'_, '_>,
Expand Down Expand Up @@ -48,8 +53,12 @@ impl SingleAttributeParser for DeprecatedParser {
Allow(Target::ForeignTy),
Allow(Target::Field),
Allow(Target::Trait),
Allow(Target::AssocTy),
Allow(Target::AssocConst),
Allow(Target::AssocConst(AssocCtxt::Impl { of_trait: false })),
Allow(Target::AssocConst(AssocCtxt::Trait)),
AllowSilent(Target::AssocConst(AssocCtxt::Impl { of_trait: true })),
Allow(Target::AssocTy(AssocCtxt::Impl { of_trait: false })),
Allow(Target::AssocTy(AssocCtxt::Trait)),
AllowSilent(Target::AssocTy(AssocCtxt::Impl { of_trait: true })),
Allow(Target::Variant),
Allow(Target::Impl { of_trait: false }),
Allow(Target::Crate),
Expand Down Expand Up @@ -182,6 +191,22 @@ impl SingleAttributeParser for DeprecatedParser {
return None;
}

// `#[deprecated]` on trait-impl associated items has no effect (deprecation comes from the
// trait definition). Methods also get `useless_deprecated` from target checking.
if matches!(
cx.target,
Target::Method(MethodKind::TraitImpl)
| Target::AssocConst(AssocCtxt::Impl { of_trait: true })
| Target::AssocTy(AssocCtxt::Impl { of_trait: true })
) {
let attr_span = cx.attr_span;
cx.emit_lint(
UNUSED_ATTRIBUTES,
DeprecatedAnnotationHasNoEffect { span: attr_span },

@JonathanBrouwer JonathanBrouwer Aug 7, 2026 •
edited by rustbot
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Does this need to be its own diagnostic rather than just the default Policy::Warn diagnostic?

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@obeis obeis Aug 15, 2026

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I think using UNUSED_ATTRIBUTES is better here because it's indicates that the attribute "has no effect" rather than saying it has a "wrong target" which is a better fit for unused attributes and unused lint group.

@JonathanBrouwer JonathanBrouwer Aug 7, 2026 •
edited by rustbot
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Is this path covered by any tests?

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@obeis obeis Aug 15, 2026

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here in tests/ui/deprecation/deprecation-sanity.rs:

#[deprecated = "hello"] //~ ERROR attribute cannot be used on
//~| WARN previously accepted
impl Default for X {
    fn default() -> Self {
        X
    }
}

attr_span,
);
}

Some(AttributeKind::Deprecated {
deprecation: Deprecation { since, note, suggestion },
span: cx.attr_span,
Expand Down
8 changes: 6 additions & 2 deletions compiler/rustc_attr_parsing/src/attributes/doc.rs
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Expand Up @@ -820,12 +820,16 @@ impl AttributeParser for DocParser {
// Allow(Target::TraitAlias),
// Allow(Target::Impl { of_trait: true }),
// Allow(Target::Impl { of_trait: false }),
// Allow(Target::AssocConst),
// Allow(Target::AssocConst(AssocCtxt::Impl { of_trait: false })),
// Allow(Target::AssocConst(AssocCtxt::Trait)),
// Allow(Target::AssocConst(AssocCtxt::Impl { of_trait: true })),
// Allow(Target::Method(MethodKind::Inherent)),
// Allow(Target::Method(MethodKind::Trait { body: true })),
// Allow(Target::Method(MethodKind::Trait { body: false })),
// Allow(Target::Method(MethodKind::TraitImpl)),
// Allow(Target::AssocTy),
// Allow(Target::AssocTy(AssocCtxt::Impl { of_trait: false })),
// Allow(Target::AssocTy(AssocCtxt::Trait)),
// Allow(Target::AssocTy(AssocCtxt::Impl { of_trait: true })),
// Allow(Target::ForeignFn),
// Allow(Target::ForeignStatic),
// Allow(Target::ForeignTy),
Expand Down
4 changes: 3 additions & 1 deletion compiler/rustc_attr_parsing/src/attributes/inline.rs
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Expand Up @@ -22,7 +22,9 @@ impl SingleAttributeParser for InlineParser {
Warn(Target::Field),
Warn(Target::MacroDef),
Warn(Target::Arm),
Warn(Target::AssocConst),
Warn(Target::AssocConst(AssocCtxt::Impl { of_trait: false })),
Warn(Target::AssocConst(AssocCtxt::Trait)),
Warn(Target::AssocConst(AssocCtxt::Impl { of_trait: true })),
Warn(Target::MacroCall),
]);
const TEMPLATE: AttributeTemplate = template!(
Expand Down
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