rustc_attr_parsing/attributes/
transparency.rs

1use rustc_feature::{AttributeTemplate, template};
2use rustc_hir::Target;
3use rustc_hir::attrs::AttributeKind;
4use rustc_span::hygiene::Transparency;
5use rustc_span::{Symbol, sym};
6
7use super::{AttributeOrder, OnDuplicate, SingleAttributeParser};
8use crate::context::MaybeWarn::Allow;
9use crate::context::{AcceptContext, AllowedTargets, Stage};
10use crate::parser::ArgParser;
11pub(crate) struct TransparencyParser;
12
13// FIXME(jdonszelmann): make these proper diagnostics
14#[allow(rustc::untranslatable_diagnostic)]
15#[allow(rustc::diagnostic_outside_of_impl)]
16impl<S: Stage> SingleAttributeParser<S> for TransparencyParser {
17    const PATH: &[Symbol] = &[sym::rustc_macro_transparency];
18    const ATTRIBUTE_ORDER: AttributeOrder = AttributeOrder::KeepInnermost;
19    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Custom(|cx, used, unused| {
20        cx.dcx().span_err(vec![used, unused], "multiple macro transparency attributes");
21    });
22    const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowList(&[Allow(Target::MacroDef)]);
23    const TEMPLATE: AttributeTemplate =
24        template!(NameValueStr: ["transparent", "semitransparent", "opaque"]);
25
26    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser<'_>) -> Option<AttributeKind> {
27        let Some(nv) = args.name_value() else {
28            cx.expected_name_value(cx.attr_span, None);
29            return None;
30        };
31        match nv.value_as_str() {
32            Some(sym::transparent) => Some(Transparency::Transparent),
33            Some(sym::semiopaque | sym::semitransparent) => Some(Transparency::SemiOpaque),
34            Some(sym::opaque) => Some(Transparency::Opaque),
35            Some(_) => {
36                cx.expected_specific_argument_strings(
37                    nv.value_span,
38                    vec!["transparent", "semitransparent", "opaque"],
39                );
40                None
41            }
42            None => None,
43        }
44        .map(AttributeKind::MacroTransparency)
45    }
46}
rustc_attr_parsing/attributes/transparency.rs

rustc_attr_parsing/attributes/
transparency.rs
