rustc_attr_parsing/attributes/
allow_unstable.rs1use std::iter;
2
3use rustc_attr_data_structures::AttributeKind;
4use rustc_feature::{AttributeTemplate, template};
5use rustc_span::{Span, Symbol, sym};
6
7use super::{CombineAttributeParser, ConvertFn};
8use crate::context::{AcceptContext, Stage};
9use crate::parser::ArgParser;
10use crate::session_diagnostics;
11
12pub(crate) struct AllowInternalUnstableParser;
13impl<S: Stage> CombineAttributeParser<S> for AllowInternalUnstableParser {
14 const PATH: &[Symbol] = &[sym::allow_internal_unstable];
15 type Item = (Symbol, Span);
16 const CONVERT: ConvertFn<Self::Item> =
17 |items, span| AttributeKind::AllowInternalUnstable(items, span);
18 const TEMPLATE: AttributeTemplate = template!(Word, List: "feat1, feat2, ...");
19
20 fn extend<'c>(
21 cx: &'c mut AcceptContext<'_, '_, S>,
22 args: &'c ArgParser<'_>,
23 ) -> impl IntoIterator<Item = Self::Item> {
24 parse_unstable(cx, args, <Self as CombineAttributeParser<S>>::PATH[0])
25 .into_iter()
26 .zip(iter::repeat(cx.attr_span))
27 }
28}
29
30pub(crate) struct AllowConstFnUnstableParser;
31impl<S: Stage> CombineAttributeParser<S> for AllowConstFnUnstableParser {
32 const PATH: &[Symbol] = &[sym::rustc_allow_const_fn_unstable];
33 type Item = Symbol;
34 const CONVERT: ConvertFn<Self::Item> =
35 |items, first_span| AttributeKind::AllowConstFnUnstable(items, first_span);
36 const TEMPLATE: AttributeTemplate = template!(Word, List: "feat1, feat2, ...");
37
38 fn extend<'c>(
39 cx: &'c mut AcceptContext<'_, '_, S>,
40 args: &'c ArgParser<'_>,
41 ) -> impl IntoIterator<Item = Self::Item> + 'c {
42 parse_unstable(cx, args, <Self as CombineAttributeParser<S>>::PATH[0])
43 }
44}
45
46fn parse_unstable<S: Stage>(
47 cx: &AcceptContext<'_, '_, S>,
48 args: &ArgParser<'_>,
49 symbol: Symbol,
50) -> impl IntoIterator<Item = Symbol> {
51 let mut res = Vec::new();
52
53 let Some(list) = args.list() else {
54 cx.emit_err(session_diagnostics::ExpectsFeatureList {
55 span: cx.attr_span,
56 name: symbol.to_ident_string(),
57 });
58 return res;
59 };
60
61 for param in list.mixed() {
62 let param_span = param.span();
63 if let Some(ident) = param.meta_item().and_then(|i| i.path().word()) {
64 res.push(ident.name);
65 } else {
66 cx.emit_err(session_diagnostics::ExpectsFeatures {
67 span: param_span,
68 name: symbol.to_ident_string(),
69 });
70 }
71 }
72
73 res
74}