Port #[rustc_deny_explicit_impl] to the new attribute system

compiler/rustc_attr_data_structures/src/attributes.rs

@@ -237,6 +237,9 @@ pub enum AttributeKind {
     /// Represents `#[const_trait]`.
     ConstTrait(Span),
 
+    ///Represents `#[rustc_deny_explicit_impl]`.
+    DenyExplicitImpl(Span),
+
     /// Represents [`#[deprecated]`](https://doc.rust-lang.org/stable/reference/attributes/diagnostics.html#the-deprecated-attribute).
     Deprecation { deprecation: Deprecation, span: Span },
 

compiler/rustc_attr_data_structures/src/encode_cross_crate.rs

@@ -24,6 +24,7 @@ impl AttributeKind {
             ConstStability { .. } => Yes,
             ConstStabilityIndirect => No,
             ConstTrait(..) => No,
+            DenyExplicitImpl(..) => No,
             Deprecation { .. } => Yes,
             DocComment { .. } => Yes,
             Dummy => No,

compiler/rustc_attr_parsing/src/attributes/traits.rs

@@ -61,3 +61,10 @@ impl<S: Stage> NoArgsAttributeParser<S> for ConstTraitParser {
     const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Warn;
     const CREATE: fn(Span) -> AttributeKind = AttributeKind::ConstTrait;
 }
+
+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;
+}

compiler/rustc_attr_parsing/src/context.rs

@@ -43,7 +43,9 @@ use crate::attributes::stability::{
     BodyStabilityParser, ConstStabilityIndirectParser, ConstStabilityParser, StabilityParser,
 };
 use crate::attributes::test_attrs::IgnoreParser;
-use crate::attributes::traits::{ConstTraitParser, SkipDuringMethodDispatchParser};
+use crate::attributes::traits::{
+    ConstTraitParser, DenyExplicitImplParser, SkipDuringMethodDispatchParser,
+};
 use crate::attributes::transparency::TransparencyParser;
 use crate::attributes::{AttributeParser as _, Combine, Single, WithoutArgs};
 use crate::parser::{ArgParser, MetaItemParser, PathParser};
@@ -151,6 +153,7 @@ attribute_parsers!(
         Single<WithoutArgs<ConstContinueParser>>,
         Single<WithoutArgs<ConstStabilityIndirectParser>>,
         Single<WithoutArgs<ConstTraitParser>>,
+        Single<WithoutArgs<DenyExplicitImplParser>>,
         Single<WithoutArgs<ExportStableParser>>,
         Single<WithoutArgs<FfiConstParser>>,
         Single<WithoutArgs<FfiPureParser>>,

compiler/rustc_hir_analysis/src/collect.rs

@@ -961,7 +961,7 @@ fn trait_def(tcx: TyCtxt<'_>, def_id: LocalDefId) -> ty::TraitDef {
             no_dups.then_some(list)
         });
 
-    let deny_explicit_impl = attrs.iter().any(|attr| attr.has_name(sym::rustc_deny_explicit_impl));
+    let deny_explicit_impl = find_attr!(attrs, AttributeKind::DenyExplicitImpl(_));
     let implement_via_object =
         !attrs.iter().any(|attr| attr.has_name(sym::rustc_do_not_implement_via_object));
 

compiler/rustc_parse/src/validate_attr.rs

@@ -283,6 +283,7 @@ pub fn check_builtin_meta_item(
                 | sym::rustc_confusables
                 | sym::rustc_skip_during_method_dispatch
                 | sym::rustc_pass_by_value
+                | sym::rustc_deny_explicit_impl
                 | sym::const_trait
                 | sym::repr
                 | sym::align

compiler/rustc_passes/src/check_attr.rs

@@ -122,7 +122,8 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
             match attr {
                 Attribute::Parsed(
                     AttributeKind::SkipDuringMethodDispatch { span: attr_span, .. }
-                    | AttributeKind::ConstTrait(attr_span),
+                    | AttributeKind::ConstTrait(attr_span)
+                    | AttributeKind::DenyExplicitImpl(attr_span),
                 ) => {
                     self.check_must_be_applied_to_trait(*attr_span, span, target);
                 }
@@ -299,7 +300,6 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
                         | [sym::rustc_then_this_would_need, ..] => self.check_rustc_dirty_clean(attr),
                         [sym::rustc_coinductive, ..]
                         | [sym::rustc_must_implement_one_of, ..]
-                        | [sym::rustc_deny_explicit_impl, ..]
                         | [sym::rustc_do_not_implement_via_object, ..]
                         => self.check_must_be_applied_to_trait(attr.span(), span, target),
                         [sym::collapse_debuginfo, ..] => self.check_collapse_debuginfo(attr, span, target),