compiler/rustc_attr_parsing/src/attributes/dummy.rs

use rustc_attr_ir::AttributeKind;
use rustc_feature::AttributeStability;
use rustc_span::{Symbol, sym};

use crate::attributes::{OnDuplicate, SingleAttributeParser};
use crate::context::AcceptContext;
use crate::parser::ArgParser;
use crate::target_checking::AllowedTargets;
use crate::{AttributeTemplate, template, unstable};

pub(crate) struct RustcDummyParser;
impl SingleAttributeParser for RustcDummyParser {
    const PATH: &[Symbol] = &[sym::rustc_dummy];
    const ON_DUPLICATE: OnDuplicate = OnDuplicate::Ignore;
    const ALLOWED_TARGETS: AllowedTargets<'_> = AllowedTargets::ManuallyChecked;
    const TEMPLATE: AttributeTemplate = template!(Word); // Anything, really
    const STABILITY: AttributeStability =
        unstable!(rustc_attrs, "the `rustc_dummy` attribute is used for rustc unit tests");

    fn convert(cx: &mut AcceptContext<'_, '_>, args: &ArgParser) -> Option<AttributeKind> {
        args.ignore_args();
        cx.ignore_target_checks();
        Some(AttributeKind::RustcDummy)
    }
}