rustc_attr_parsing/attributes/
transparency.rs

1use rustc_span::hygiene::Transparency;
2
3use super::prelude::*;
4
5pub(crate) struct TransparencyParser;
6
7// FIXME(jdonszelmann): make these proper diagnostics
8#[allow(rustc::untranslatable_diagnostic)]
9#[allow(rustc::diagnostic_outside_of_impl)]
10impl<S: Stage> SingleAttributeParser<S> for TransparencyParser {
11    const PATH: &[Symbol] = &[sym::rustc_macro_transparency];
12    const ATTRIBUTE_ORDER: AttributeOrder = AttributeOrder::KeepInnermost;
13    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Custom(|cx, used, unused| {
14        cx.dcx().span_err(vec![used, unused], "multiple macro transparency attributes");
15    });
16    const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowList(&[Allow(Target::MacroDef)]);
17    const TEMPLATE: AttributeTemplate =
18        template!(NameValueStr: ["transparent", "semitransparent", "opaque"]);
19
20    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser<'_>) -> Option<AttributeKind> {
21        let Some(nv) = args.name_value() else {
22            cx.expected_name_value(cx.attr_span, None);
23            return None;
24        };
25        match nv.value_as_str() {
26            Some(sym::transparent) => Some(Transparency::Transparent),
27            Some(sym::semiopaque | sym::semitransparent) => Some(Transparency::SemiOpaque),
28            Some(sym::opaque) => Some(Transparency::Opaque),
29            Some(_) => {
30                cx.expected_specific_argument_strings(
31                    nv.value_span,
32                    &[sym::transparent, sym::semitransparent, sym::opaque],
33                );
34                None
35            }
36            None => None,
37        }
38        .map(AttributeKind::MacroTransparency)
39    }
40}
rustc_attr_parsing/attributes/transparency.rs

rustc_attr_parsing/attributes/
transparency.rs
