1 use crate::attr::HasAttrs;
3 use crate::source_map::{hygiene, ExpnInfo, ExpnFormat};
4 use crate::ext::base::ExtCtxt;
5 use crate::ext::build::AstBuilder;
6 use crate::parse::parser::PathStyle;
7 use crate::symbol::Symbol;
11 use rustc_data_structures::fx::FxHashSet;
13 pub fn collect_derives(cx: &mut ExtCtxt<'_>, attrs: &mut Vec<ast::Attribute>) -> Vec<ast::Path> {
14 let mut result = Vec::new();
16 if attr.path != "derive" {
19 if !attr.is_meta_item_list() {
20 cx.span_err(attr.span,
21 "attribute must be of the form `#[derive(Trait1, Trait2, ...)]`");
25 match attr.parse_list(cx.parse_sess,
26 |parser| parser.parse_path_allowing_meta(PathStyle::Mod)) {
27 Ok(ref traits) if traits.is_empty() => {
28 cx.span_warn(attr.span, "empty trait list in `derive`");
32 result.extend(traits);
44 pub fn add_derived_markers<T>(cx: &mut ExtCtxt<'_>, span: Span, traits: &[ast::Path], item: &mut T)
47 let (mut names, mut pretty_name) = (FxHashSet::default(), "derive(".to_owned());
48 for (i, path) in traits.iter().enumerate() {
50 pretty_name.push_str(", ");
52 pretty_name.push_str(&path.to_string());
53 names.insert(unwrap_or!(path.segments.get(0), continue).ident.name);
55 pretty_name.push(')');
57 cx.current_expansion.mark.set_expn_info(ExpnInfo {
60 format: ExpnFormat::MacroAttribute(Symbol::intern(&pretty_name)),
61 allow_internal_unstable: true,
62 allow_internal_unsafe: false,
63 local_inner_macros: false,
64 edition: hygiene::default_edition(),
67 let span = span.with_ctxt(cx.backtrace());
68 item.visit_attrs(|attrs| {
69 if names.contains(&Symbol::intern("Eq")) && names.contains(&Symbol::intern("PartialEq")) {
70 let meta = cx.meta_word(span, Symbol::intern("structural_match"));
71 attrs.push(cx.attribute(span, meta));
73 if names.contains(&Symbol::intern("Copy")) {
74 let meta = cx.meta_word(span, Symbol::intern("rustc_copy_clone_marker"));
75 attrs.push(cx.attribute(span, meta));