rustc_attr_parsing/attributes/
allow_unstable.rs

1use std::iter;
2
3use rustc_feature::{AttributeTemplate, template};
4use rustc_hir::attrs::AttributeKind;
5use rustc_hir::{MethodKind, Target};
6use rustc_span::{Span, Symbol, sym};
7
8use super::{CombineAttributeParser, ConvertFn};
9use crate::context::MaybeWarn::{Allow, Warn};
10use crate::context::{AcceptContext, AllowedTargets, Stage};
11use crate::parser::ArgParser;
12use crate::session_diagnostics;
13
14pub(crate) struct AllowInternalUnstableParser;
15impl<S: Stage> CombineAttributeParser<S> for AllowInternalUnstableParser {
16    const PATH: &[Symbol] = &[sym::allow_internal_unstable];
17    type Item = (Symbol, Span);
18    const CONVERT: ConvertFn<Self::Item> =
19        |items, span| AttributeKind::AllowInternalUnstable(items, span);
20    const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowList(&[
21        Allow(Target::MacroDef),
22        Allow(Target::Fn),
23        Warn(Target::Field),
24        Warn(Target::Arm),
25    ]);
26    const TEMPLATE: AttributeTemplate = template!(Word, List: &["feat1, feat2, ..."]);
27
28    fn extend<'c>(
29        cx: &'c mut AcceptContext<'_, '_, S>,
30        args: &'c ArgParser<'_>,
31    ) -> impl IntoIterator<Item = Self::Item> {
32        parse_unstable(cx, args, <Self as CombineAttributeParser<S>>::PATH[0])
33            .into_iter()
34            .zip(iter::repeat(cx.attr_span))
35    }
36}
37
38pub(crate) struct UnstableFeatureBoundParser;
39impl<S: Stage> CombineAttributeParser<S> for UnstableFeatureBoundParser {
40    const PATH: &'static [rustc_span::Symbol] = &[sym::unstable_feature_bound];
41    type Item = (Symbol, Span);
42    const CONVERT: ConvertFn<Self::Item> = |items, _| AttributeKind::UnstableFeatureBound(items);
43    const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowList(&[
44        Allow(Target::Fn),
45        Allow(Target::Impl { of_trait: true }),
46        Allow(Target::Trait),
47    ]);
48    const TEMPLATE: AttributeTemplate = template!(Word, List: &["feat1, feat2, ..."]);
49
50    fn extend<'c>(
51        cx: &'c mut AcceptContext<'_, '_, S>,
52        args: &'c ArgParser<'_>,
53    ) -> impl IntoIterator<Item = Self::Item> {
54        if !cx.features().staged_api() {
55            cx.emit_err(session_diagnostics::StabilityOutsideStd { span: cx.attr_span });
56        }
57        parse_unstable(cx, args, <Self as CombineAttributeParser<S>>::PATH[0])
58            .into_iter()
59            .zip(iter::repeat(cx.attr_span))
60    }
61}
62
63pub(crate) struct AllowConstFnUnstableParser;
64impl<S: Stage> CombineAttributeParser<S> for AllowConstFnUnstableParser {
65    const PATH: &[Symbol] = &[sym::rustc_allow_const_fn_unstable];
66    type Item = Symbol;
67    const CONVERT: ConvertFn<Self::Item> =
68        |items, first_span| AttributeKind::AllowConstFnUnstable(items, first_span);
69    const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowList(&[
70        Allow(Target::Fn),
71        Allow(Target::Method(MethodKind::Inherent)),
72        Allow(Target::Method(MethodKind::Trait { body: false })),
73        Allow(Target::Method(MethodKind::Trait { body: true })),
74        Allow(Target::Method(MethodKind::TraitImpl)),
75    ]);
76    const TEMPLATE: AttributeTemplate = template!(Word, List: &["feat1, feat2, ..."]);
77
78    fn extend<'c>(
79        cx: &'c mut AcceptContext<'_, '_, S>,
80        args: &'c ArgParser<'_>,
81    ) -> impl IntoIterator<Item = Self::Item> + 'c {
82        parse_unstable(cx, args, <Self as CombineAttributeParser<S>>::PATH[0])
83    }
84}
85
86fn parse_unstable<S: Stage>(
87    cx: &AcceptContext<'_, '_, S>,
88    args: &ArgParser<'_>,
89    symbol: Symbol,
90) -> impl IntoIterator<Item = Symbol> {
91    let mut res = Vec::new();
92
93    let Some(list) = args.list() else {
94        cx.emit_err(session_diagnostics::ExpectsFeatureList {
95            span: cx.attr_span,
96            name: symbol.to_ident_string(),
97        });
98        return res;
99    };
100
101    for param in list.mixed() {
102        let param_span = param.span();
103        if let Some(ident) = param.meta_item().and_then(|i| i.path().word()) {
104            res.push(ident.name);
105        } else {
106            cx.emit_err(session_diagnostics::ExpectsFeatures {
107                span: param_span,
108                name: symbol.to_ident_string(),
109            });
110        }
111    }
112
113    res
114}
rustc_attr_parsing/attributes/allow_unstable.rs

rustc_attr_parsing/attributes/
allow_unstable.rs
