Rollup merge of #143403 - GrigorenkoPV:attributes/traits, r=jdonszelmann

Port several trait/coherence-related attributes the new attribute system

Part of rust-lang/rust#131229

This ports:
- `#[const_trait]`
- `#[rustc_deny_explicit_impl]`
- `#[rustc_do_not_implement_via_object]`
- `#[rustc_coinductive]`
- `#[type_const]`
- `#[rustc_specialization_trait]`
- `#[rustc_unsafe_specialization_marker]`
- `#[marker]`
- `#[fundamental]`
- `#[rustc_paren_sugar]`
- `#[rustc_allow_incoherent_impl]`
- `#[rustc_coherence_is_core]`

This also changes `#[marker]` to error on duplicates instead of warning.
cc rust-lang/rust#142838, but I don't think it matters too much, since it's unstable.

r? ``@oli-obk``

compiler/rustc_attr_parsing/src/attributes/traits.rs

@@ -2,14 +2,15 @@ use core::mem;
 
 use rustc_attr_data_structures::AttributeKind;
 use rustc_feature::{AttributeTemplate, template};
-use rustc_span::{Symbol, sym};
+use rustc_span::{Span, Symbol, sym};
 
-use crate::attributes::{AttributeOrder, OnDuplicate, SingleAttributeParser};
+use crate::attributes::{
+    AttributeOrder, NoArgsAttributeParser, OnDuplicate, SingleAttributeParser,
+};
 use crate::context::{AcceptContext, Stage};
 use crate::parser::ArgParser;
 
 pub(crate) struct SkipDuringMethodDispatchParser;
-
 impl<S: Stage> SingleAttributeParser<S> for SkipDuringMethodDispatchParser {
     const PATH: &[Symbol] = &[sym::rustc_skip_during_method_dispatch];
     const ATTRIBUTE_ORDER: AttributeOrder = AttributeOrder::KeepInnermost;
@@ -52,3 +53,95 @@ impl<S: Stage> SingleAttributeParser<S> for SkipDuringMethodDispatchParser {
         Some(AttributeKind::SkipDuringMethodDispatch { array, boxed_slice, span: cx.attr_span })
     }
 }
+
+pub(crate) struct ParenSugarParser;
+impl<S: Stage> NoArgsAttributeParser<S> for ParenSugarParser {
+    const PATH: &[Symbol] = &[sym::rustc_paren_sugar];
+    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Error;
+    const CREATE: fn(Span) -> AttributeKind = AttributeKind::ParenSugar;
+}
+
+pub(crate) struct TypeConstParser;
+impl<S: Stage> NoArgsAttributeParser<S> for TypeConstParser {
+    const PATH: &[Symbol] = &[sym::type_const];
+    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Error;
+    const CREATE: fn(Span) -> AttributeKind = AttributeKind::TypeConst;
+}
+
+// Markers
+
+pub(crate) struct MarkerParser;
+impl<S: Stage> NoArgsAttributeParser<S> for MarkerParser {
+    const PATH: &[Symbol] = &[sym::marker];
+    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Warn;
+    const CREATE: fn(Span) -> AttributeKind = AttributeKind::Marker;
+}
+
+pub(crate) struct DenyExplicitImplParser;
+impl<S: Stage> NoArgsAttributeParser<S> for DenyExplicitImplParser {
+    const PATH: &[Symbol] = &[sym::rustc_deny_explicit_impl];
+    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Error;
+    const CREATE: fn(Span) -> AttributeKind = AttributeKind::DenyExplicitImpl;
+}
+
+pub(crate) struct DoNotImplementViaObjectParser;
+impl<S: Stage> NoArgsAttributeParser<S> for DoNotImplementViaObjectParser {
+    const PATH: &[Symbol] = &[sym::rustc_do_not_implement_via_object];
+    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Error;
+    const CREATE: fn(Span) -> AttributeKind = AttributeKind::DoNotImplementViaObject;
+}
+
+// Const traits
+
+pub(crate) struct ConstTraitParser;
+impl<S: Stage> NoArgsAttributeParser<S> for ConstTraitParser {
+    const PATH: &[Symbol] = &[sym::const_trait];
+    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Warn;
+    const CREATE: fn(Span) -> AttributeKind = AttributeKind::ConstTrait;
+}
+
+// Specialization
+
+pub(crate) struct SpecializationTraitParser;
+impl<S: Stage> NoArgsAttributeParser<S> for SpecializationTraitParser {
+    const PATH: &[Symbol] = &[sym::rustc_specialization_trait];
+    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Error;
+    const CREATE: fn(Span) -> AttributeKind = AttributeKind::SpecializationTrait;
+}
+
+pub(crate) struct UnsafeSpecializationMarkerParser;
+impl<S: Stage> NoArgsAttributeParser<S> for UnsafeSpecializationMarkerParser {
+    const PATH: &[Symbol] = &[sym::rustc_unsafe_specialization_marker];
+    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Error;
+    const CREATE: fn(Span) -> AttributeKind = AttributeKind::UnsafeSpecializationMarker;
+}
+
+// Coherence
+
+pub(crate) struct CoinductiveParser;
+impl<S: Stage> NoArgsAttributeParser<S> for CoinductiveParser {
+    const PATH: &[Symbol] = &[sym::rustc_coinductive];
+    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Error;
+    const CREATE: fn(Span) -> AttributeKind = AttributeKind::Coinductive;
+}
+
+pub(crate) struct AllowIncoherentImplParser;
+impl<S: Stage> NoArgsAttributeParser<S> for AllowIncoherentImplParser {
+    const PATH: &[Symbol] = &[sym::rustc_allow_incoherent_impl];
+    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Error;
+    const CREATE: fn(Span) -> AttributeKind = AttributeKind::AllowIncoherentImpl;
+}
+
+pub(crate) struct CoherenceIsCoreParser;
+impl<S: Stage> NoArgsAttributeParser<S> for CoherenceIsCoreParser {
+    const PATH: &[Symbol] = &[sym::rustc_coherence_is_core];
+    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Error;
+    const CREATE: fn(Span) -> AttributeKind = |_| AttributeKind::CoherenceIsCore;
+}
+
+pub(crate) struct FundamentalParser;
+impl<S: Stage> NoArgsAttributeParser<S> for FundamentalParser {
+    const PATH: &[Symbol] = &[sym::fundamental];
+    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Error;
+    const CREATE: fn(Span) -> AttributeKind = |_| AttributeKind::Fundamental;
+}