Port rustc_strict_coherence to the new attribute parser

Author: jdonszelmann

compiler/rustc_attr_parsing/src/attributes/rustc_internal.rs

@@ -760,3 +760,18 @@ impl<S: Stage> NoArgsAttributeParser<S> for RustcEffectiveVisibilityParser {
     ]);
     const CREATE: fn(Span) -> AttributeKind = |_| AttributeKind::RustcEffectiveVisibility;
 }
+
+pub(crate) struct RustcStrictCoherenceParser;
+
+impl<S: Stage> NoArgsAttributeParser<S> for RustcStrictCoherenceParser {
+    const PATH: &'static [Symbol] = &[sym::rustc_strict_coherence];
+    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Error;
+    const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowList(&[
+        Allow(Target::Trait),
+        Allow(Target::Struct),
+        Allow(Target::Enum),
+        Allow(Target::Union),
+        Allow(Target::ForeignTy),
+    ]);
+    const CREATE: fn(Span) -> AttributeKind = AttributeKind::RustcStrictCoherence;
+}

compiler/rustc_attr_parsing/src/context.rs

@@ -275,6 +275,7 @@ attribute_parsers!(
         Single<WithoutArgs<RustcPreserveUbChecksParser>>,
         Single<WithoutArgs<RustcReallocatorParser>>,
         Single<WithoutArgs<RustcShouldNotBeCalledOnConstItems>>,
+        Single<WithoutArgs<RustcStrictCoherenceParser>>,
         Single<WithoutArgs<RustcVarianceOfOpaquesParser>>,
         Single<WithoutArgs<RustcVarianceParser>>,
         Single<WithoutArgs<SpecializationTraitParser>>,

compiler/rustc_hir/src/attrs/data_structures.rs

@@ -1218,6 +1218,9 @@ pub enum AttributeKind {
     /// Represents `#[rustc_std_internal_symbol]`.
     RustcStdInternalSymbol(Span),
 
+    /// Represents `#[rustc_strict_coherence]`.
+    RustcStrictCoherence(Span),
+
     /// Represents `#[rustc_then_this_would_need]`
     RustcThenThisWouldNeed(Span, ThinVec<Ident>),
 

compiler/rustc_hir/src/attrs/encode_cross_crate.rs

@@ -149,6 +149,7 @@ impl AttributeKind {
             RustcSkipDuringMethodDispatch { .. } => No,
             RustcSpecializationTrait(..) => No,
             RustcStdInternalSymbol(..) => No,
+            RustcStrictCoherence(..) => Yes,
             RustcThenThisWouldNeed(..) => No,
             RustcUnsafeSpecializationMarker(..) => No,
             RustcVariance => No,

compiler/rustc_middle/src/traits/specialization_graph.rs

@@ -1,8 +1,9 @@
 use rustc_data_structures::fx::FxIndexMap;
 use rustc_errors::ErrorGuaranteed;
+use rustc_hir::attrs::AttributeKind;
 use rustc_hir::def_id::{DefId, DefIdMap};
+use rustc_hir::find_attr;
 use rustc_macros::{HashStable, TyDecodable, TyEncodable};
-use rustc_span::sym;
 
 use crate::error::StrictCoherenceNeedsNegativeCoherence;
 use crate::ty::fast_reject::SimplifiedType;
@@ -61,23 +62,15 @@ pub enum OverlapMode {
 impl OverlapMode {
     pub fn get(tcx: TyCtxt<'_>, trait_id: DefId) -> OverlapMode {
         let with_negative_coherence = tcx.features().with_negative_coherence();
-        let strict_coherence = tcx.has_attr(trait_id, sym::rustc_strict_coherence);
+        let strict_coherence = find_attr!(tcx.get_all_attrs(trait_id), AttributeKind::RustcStrictCoherence(span) => *span);
 
         if with_negative_coherence {
-            if strict_coherence { OverlapMode::Strict } else { OverlapMode::WithNegative }
+            if strict_coherence.is_some() { OverlapMode::Strict } else { OverlapMode::WithNegative }
         } else {
-            if strict_coherence {
-                let attr_span = trait_id
-                    .as_local()
-                    .into_iter()
-                    .flat_map(|local_def_id| {
-                        tcx.hir_attrs(tcx.local_def_id_to_hir_id(local_def_id))
-                    })
-                    .find(|attr| attr.has_name(sym::rustc_strict_coherence))
-                    .map(|attr| attr.span());
+            if let Some(span) = strict_coherence {
                 tcx.dcx().emit_err(StrictCoherenceNeedsNegativeCoherence {
                     span: tcx.def_span(trait_id),
-                    attr_span,
+                    attr_span: span,
                 });
             }
             OverlapMode::Stable

compiler/rustc_passes/src/check_attr.rs

@@ -340,6 +340,7 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
                     | AttributeKind::RustcSkipDuringMethodDispatch { .. }
                     | AttributeKind::RustcSpecializationTrait(..)
                     | AttributeKind::RustcStdInternalSymbol (..)
+                    | AttributeKind::RustcStrictCoherence(..)
                     | AttributeKind::RustcThenThisWouldNeed(..)
                     | AttributeKind::RustcUnsafeSpecializationMarker(..)
                     | AttributeKind::RustcVariance
@@ -400,7 +401,6 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
                             | sym::rustc_autodiff
                             | sym::rustc_capture_analysis
                             | sym::rustc_regions
-                            | sym::rustc_strict_coherence
                             | sym::rustc_mir
                             | sym::rustc_outlives
                             | sym::rustc_symbol_name