Port rustc_reservation_impl to the new attribute parser

Author: jdonszelmann

compiler/rustc_attr_parsing/src/attributes/rustc_internal.rs

@@ -845,3 +845,29 @@ impl<S: Stage> NoArgsAttributeParser<S> for RustcIntrinsicConstStableIndirectPar
     const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowList(&[Allow(Target::Fn)]);
     const CREATE: fn(Span) -> AttributeKind = |_| AttributeKind::RustcIntrinsicConstStableIndirect;
 }
+
+pub(crate) struct RustcReservationImplParser;
+
+impl<S: Stage> SingleAttributeParser<S> for RustcReservationImplParser {
+    const PATH: &[Symbol] = &[sym::rustc_reservation_impl];
+    const ATTRIBUTE_ORDER: AttributeOrder = AttributeOrder::KeepOutermost;
+    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Error;
+    const ALLOWED_TARGETS: AllowedTargets =
+        AllowedTargets::AllowList(&[Allow(Target::Impl { of_trait: true })]);
+
+    const TEMPLATE: AttributeTemplate = template!(NameValueStr: "reservation message");
+
+    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser) -> Option<AttributeKind> {
+        let Some(nv) = args.name_value() else {
+            cx.expected_name_value(args.span().unwrap_or(cx.attr_span), None);
+            return None;
+        };
+
+        let Some(value_str) = nv.value_as_str() else {
+            cx.expected_string_literal(nv.value_span, Some(nv.value_as_lit()));
+            return None;
+        };
+
+        Some(AttributeKind::RustcReservationImpl(cx.attr_span, value_str))
+    }
+}

compiler/rustc_attr_parsing/src/context.rs

@@ -209,6 +209,7 @@ attribute_parsers!(
         Single<RustcLintOptDenyFieldAccessParser>,
         Single<RustcMustImplementOneOfParser>,
         Single<RustcObjectLifetimeDefaultParser>,
+        Single<RustcReservationImplParser>,
         Single<RustcScalableVectorParser>,
         Single<RustcSimdMonomorphizeLaneLimitParser>,
         Single<RustcSymbolName>,

compiler/rustc_hir/src/attrs/data_structures.rs

@@ -1207,6 +1207,9 @@ pub enum AttributeKind {
     /// Represents `#[rustc_regions]`
     RustcRegions,
 
+    /// Represents `#[rustc_reservation_impl]`
+    RustcReservationImpl(Span, Symbol),
+
     /// Represents `#[rustc_scalable_vector(N)]`
     RustcScalableVector {
         /// The base multiple of lanes that are in a scalable vector, if provided. `element_count`

compiler/rustc_hir/src/attrs/encode_cross_crate.rs

@@ -147,6 +147,7 @@ impl AttributeKind {
             RustcPubTransparent(..) => Yes,
             RustcReallocator => No,
             RustcRegions => No,
+            RustcReservationImpl(..) => Yes,
             RustcScalableVector { .. } => Yes,
             RustcShouldNotBeCalledOnConstItems(..) => Yes,
             RustcSimdMonomorphizeLaneLimit(..) => Yes, // Affects layout computation, which needs to work cross-crate

compiler/rustc_hir_analysis/src/collect.rs

@@ -1274,7 +1274,8 @@ fn impl_trait_header(tcx: TyCtxt<'_>, def_id: LocalDefId) -> ty::ImplTraitHeader
         .of_trait
         .unwrap_or_else(|| panic!("expected impl trait, found inherent impl on {def_id:?}"));
     let selfty = tcx.type_of(def_id).instantiate_identity();
-    let is_rustc_reservation = tcx.has_attr(def_id, sym::rustc_reservation_impl);
+    let is_rustc_reservation =
+        find_attr!(tcx.get_all_attrs(def_id), AttributeKind::RustcReservationImpl(..));
 
     check_impl_constness(tcx, impl_.constness, &of_trait.trait_ref);
 

compiler/rustc_passes/src/check_attr.rs

@@ -338,6 +338,7 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
                     | AttributeKind::RustcPreserveUbChecks
                     | AttributeKind::RustcReallocator
                     | AttributeKind::RustcRegions
+                    | AttributeKind::RustcReservationImpl(..)
                     | AttributeKind::RustcScalableVector { .. }
                     | AttributeKind::RustcShouldNotBeCalledOnConstItems(..)
                     | AttributeKind::RustcSimdMonomorphizeLaneLimit(..)
@@ -392,7 +393,6 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
                             | sym::rustc_trivial_field_reads
                             | sym::rustc_on_unimplemented
                             | sym::rustc_do_not_const_check
-                            | sym::rustc_reservation_impl
                             | sym::rustc_doc_primitive
                             | sym::rustc_conversion_suggestion
                             | sym::rustc_deprecated_safe_2024

compiler/rustc_trait_selection/src/traits/coherence.rs

@@ -8,8 +8,10 @@ use std::fmt::Debug;
 
 use rustc_data_structures::fx::{FxHashSet, FxIndexSet};
 use rustc_errors::{Diag, EmissionGuarantee};
+use rustc_hir::attrs::AttributeKind;
 use rustc_hir::def::DefKind;
 use rustc_hir::def_id::{CRATE_DEF_ID, DefId};
+use rustc_hir::find_attr;
 use rustc_infer::infer::{DefineOpaqueTypes, InferCtxt, TyCtxtInferExt};
 use rustc_infer::traits::PredicateObligations;
 use rustc_macros::{TypeFoldable, TypeVisitable};
@@ -23,7 +25,7 @@ use rustc_middle::ty::{
 };
 pub use rustc_next_trait_solver::coherence::*;
 use rustc_next_trait_solver::solve::SolverDelegateEvalExt;
-use rustc_span::{DUMMY_SP, Span, sym};
+use rustc_span::{DUMMY_SP, Span};
 use tracing::{debug, instrument, warn};
 
 use super::ObligationCtxt;
@@ -758,10 +760,7 @@ impl<'a, 'tcx> ProofTreeVisitor<'tcx> for AmbiguityCausesVisitor<'a, 'tcx> {
             } = cand.kind()
                 && let ty::ImplPolarity::Reservation = infcx.tcx.impl_polarity(def_id)
             {
-                let message = infcx
-                    .tcx
-                    .get_attr(def_id, sym::rustc_reservation_impl)
-                    .and_then(|a| a.value_str());
+                let message = find_attr!(infcx.tcx.get_all_attrs(def_id), AttributeKind::RustcReservationImpl(_, message) => *message);
                 if let Some(message) = message {
                     self.causes.insert(IntercrateAmbiguityCause::ReservationImpl { message });
                 }

compiler/rustc_trait_selection/src/traits/select/mod.rs

@@ -12,9 +12,9 @@ use rustc_data_structures::assert_matches;
 use rustc_data_structures::fx::{FxIndexMap, FxIndexSet};
 use rustc_data_structures::stack::ensure_sufficient_stack;
 use rustc_errors::{Diag, EmissionGuarantee};
-use rustc_hir as hir;
-use rustc_hir::LangItem;
+use rustc_hir::attrs::AttributeKind;
 use rustc_hir::def_id::DefId;
+use rustc_hir::{self as hir, LangItem, find_attr};
 use rustc_infer::infer::BoundRegionConversionTime::{self, HigherRankedType};
 use rustc_infer::infer::DefineOpaqueTypes;
 use rustc_infer::infer::at::ToTrace;
@@ -33,7 +33,7 @@ use rustc_middle::ty::{
     may_use_unstable_feature,
 };
 use rustc_next_trait_solver::solve::AliasBoundKind;
-use rustc_span::{Symbol, sym};
+use rustc_span::Symbol;
 use tracing::{debug, instrument, trace};
 
 use self::EvaluationResult::*;
@@ -1445,8 +1445,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
             && let ty::ImplPolarity::Reservation = tcx.impl_polarity(def_id)
         {
             if let Some(intercrate_ambiguity_clauses) = &mut self.intercrate_ambiguity_causes {
-                let message =
-                    tcx.get_attr(def_id, sym::rustc_reservation_impl).and_then(|a| a.value_str());
+                let message = find_attr!(tcx.get_all_attrs(def_id), AttributeKind::RustcReservationImpl(_, message) => *message);
                 if let Some(message) = message {
                     debug!(
                         "filter_reservation_impls: \