Port #[rustc_object_lifetime_default] to the new attribute parsing infrastructure

compiler/rustc_attr_parsing/src/attributes/rustc_internal.rs

@@ -57,3 +57,21 @@ fn parse_rustc_layout_scalar_valid_range<S: Stage>(
     };
     Some(Box::new(num.0))
 }
+
+pub(crate) struct RustcObjectLifetimeDefaultParser;
+
+impl<S: Stage> SingleAttributeParser<S> for RustcObjectLifetimeDefaultParser {
+    const PATH: &[rustc_span::Symbol] = &[sym::rustc_object_lifetime_default];
+    const ATTRIBUTE_ORDER: AttributeOrder = AttributeOrder::KeepFirst;
+    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Error;
+    const TEMPLATE: AttributeTemplate = template!(Word);
+
+    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser<'_>) -> Option<AttributeKind> {
+        if let Err(span) = args.no_args() {
+            cx.expected_no_args(span);
+            return None;
+        }
+
+        Some(AttributeKind::RustcObjectLifetimeDefault)
+    }
+}

compiler/rustc_attr_parsing/src/context.rs

@@ -29,6 +29,7 @@ use crate::attributes::must_use::MustUseParser;
 use crate::attributes::repr::{AlignParser, ReprParser};
 use crate::attributes::rustc_internal::{
     RustcLayoutScalarValidRangeEnd, RustcLayoutScalarValidRangeStart,
+    RustcObjectLifetimeDefaultParser,
 };
 use crate::attributes::semantics::MayDangleParser;
 use crate::attributes::stability::{
@@ -136,6 +137,7 @@ attribute_parsers!(
         Single<RustcForceInlineParser>,
         Single<RustcLayoutScalarValidRangeEnd>,
         Single<RustcLayoutScalarValidRangeStart>,
+        Single<RustcObjectLifetimeDefaultParser>,
         Single<SkipDuringMethodDispatchParser>,
         Single<TrackCallerParser>,
         Single<TransparencyParser>,