rustc_attr_parsing/attributes/
transparency.rs

1use rustc_span::hygiene::Transparency;
2
3use super::prelude::*;
4
5pub(crate) struct TransparencyParser;
6
7impl<S: Stage> SingleAttributeParser<S> for TransparencyParser {
8    const PATH: &[Symbol] = &[sym::rustc_macro_transparency];
9    const ATTRIBUTE_ORDER: AttributeOrder = AttributeOrder::KeepInnermost;
10    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Custom(|cx, used, unused| {
11        cx.dcx().span_err(<[_]>::into_vec(::alloc::boxed::box_new([used, unused]))vec![used, unused], "multiple macro transparency attributes");
12    });
13    const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowList(&[Allow(Target::MacroDef)]);
14    const TEMPLATE: AttributeTemplate =
15        ::rustc_feature::AttributeTemplate {
    word: false,
    list: None,
    one_of: &[],
    name_value_str: Some(&["transparent", "semiopaque", "opaque"]),
    docs: None,
}template!(NameValueStr: ["transparent", "semiopaque", "opaque"]);
16
17    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser) -> Option<AttributeKind> {
18        let Some(nv) = args.name_value() else {
19            cx.expected_name_value(cx.attr_span, None);
20            return None;
21        };
22        match nv.value_as_str() {
23            Some(sym::transparent) => Some(Transparency::Transparent),
24            Some(sym::semiopaque) => Some(Transparency::SemiOpaque),
25            Some(sym::opaque) => Some(Transparency::Opaque),
26            Some(_) => {
27                cx.expected_specific_argument_strings(
28                    nv.value_span,
29                    &[sym::transparent, sym::semiopaque, sym::opaque],
30                );
31                None
32            }
33            None => None,
34        }
35        .map(AttributeKind::RustcMacroTransparency)
36    }
37}
rustc_attr_parsing/attributes/transparency.rs

rustc_attr_parsing/attributes/
transparency.rs
