rustc_attr_parsing/attributes/
util.rs

1use rustc_ast::attr::{AttributeExt, first_attr_value_str_by_name};
2use rustc_attr_data_structures::RustcVersion;
3use rustc_feature::is_builtin_attr_name;
4use rustc_span::{Symbol, sym};
5
6/// Parse a rustc version number written inside string literal in an attribute,
7/// like appears in `since = "1.0.0"`. Suffixes like "-dev" and "-nightly" are
8/// not accepted in this position, unlike when parsing CFG_RELEASE.
9pub fn parse_version(s: Symbol) -> Option<RustcVersion> {
10    let mut components = s.as_str().split('-');
11    let d = components.next()?;
12    if components.next().is_some() {
13        return None;
14    }
15    let mut digits = d.splitn(3, '.');
16    let major = digits.next()?.parse().ok()?;
17    let minor = digits.next()?.parse().ok()?;
18    let patch = digits.next().unwrap_or("0").parse().ok()?;
19    Some(RustcVersion { major, minor, patch })
20}
21
22pub fn is_builtin_attr(attr: &impl AttributeExt) -> bool {
23    attr.is_doc_comment() || attr.ident().is_some_and(|ident| is_builtin_attr_name(ident.name))
24}
25
26pub fn find_crate_name(attrs: &[impl AttributeExt]) -> Option<Symbol> {
27    first_attr_value_str_by_name(attrs, sym::crate_name)
28}
29
30pub fn is_doc_alias_attrs_contain_symbol<'tcx, T: AttributeExt + 'tcx>(
31    attrs: impl Iterator<Item = &'tcx T>,
32    symbol: Symbol,
33) -> bool {
34    let doc_attrs = attrs.filter(|attr| attr.has_name(sym::doc));
35    for attr in doc_attrs {
36        let Some(values) = attr.meta_item_list() else {
37            continue;
38        };
39        let alias_values = values.iter().filter(|v| v.has_name(sym::alias));
40        for v in alias_values {
41            if let Some(nested) = v.meta_item_list() {
42                // #[doc(alias("foo", "bar"))]
43                let mut iter = nested.iter().filter_map(|item| item.lit()).map(|item| item.symbol);
44                if iter.any(|s| s == symbol) {
45                    return true;
46                }
47            } else if let Some(meta) = v.meta_item()
48                && let Some(lit) = meta.name_value_literal()
49            {
50                // #[doc(alias = "foo")]
51                if lit.symbol == symbol {
52                    return true;
53                }
54            }
55        }
56    }
57    false
58}