81 lines
2.7 KiB
Rust
81 lines
2.7 KiB
Rust
use crate::attr::HasAttrs;
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use crate::ast;
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use crate::source_map::{hygiene, ExpnInfo, ExpnFormat};
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use crate::ext::base::ExtCtxt;
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use crate::ext::build::AstBuilder;
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use crate::parse::parser::PathStyle;
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use crate::symbol::Symbol;
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use syntax_pos::Span;
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use rustc_data_structures::fx::FxHashSet;
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pub fn collect_derives(cx: &mut ExtCtxt<'_>, attrs: &mut Vec<ast::Attribute>) -> Vec<ast::Path> {
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let mut result = Vec::new();
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attrs.retain(|attr| {
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if attr.path != "derive" {
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return true;
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}
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if !attr.is_meta_item_list() {
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cx.span_err(attr.span,
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"attribute must be of the form `#[derive(Trait1, Trait2, ...)]`");
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return false;
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}
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match attr.parse_list(cx.parse_sess,
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|parser| parser.parse_path_allowing_meta(PathStyle::Mod)) {
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Ok(ref traits) if traits.is_empty() => {
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cx.span_warn(attr.span, "empty trait list in `derive`");
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false
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}
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Ok(traits) => {
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result.extend(traits);
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true
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}
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Err(mut e) => {
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e.emit();
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false
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}
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}
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});
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result
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}
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pub fn add_derived_markers<T>(cx: &mut ExtCtxt<'_>, span: Span, traits: &[ast::Path], item: &mut T)
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where T: HasAttrs,
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{
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let (mut names, mut pretty_name) = (FxHashSet::default(), "derive(".to_owned());
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for (i, path) in traits.iter().enumerate() {
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if i > 0 {
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pretty_name.push_str(", ");
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}
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pretty_name.push_str(&path.to_string());
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names.insert(unwrap_or!(path.segments.get(0), continue).ident.name);
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}
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pretty_name.push(')');
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cx.current_expansion.mark.set_expn_info(ExpnInfo {
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call_site: span,
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def_site: None,
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format: ExpnFormat::MacroAttribute(Symbol::intern(&pretty_name)),
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allow_internal_unstable: Some(vec![
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Symbol::intern("rustc_attrs"),
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Symbol::intern("structural_match"),
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].into()),
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allow_internal_unsafe: false,
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local_inner_macros: false,
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edition: hygiene::default_edition(),
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});
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let span = span.with_ctxt(cx.backtrace());
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item.visit_attrs(|attrs| {
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if names.contains(&Symbol::intern("Eq")) && names.contains(&Symbol::intern("PartialEq")) {
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let meta = cx.meta_word(span, Symbol::intern("structural_match"));
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attrs.push(cx.attribute(span, meta));
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}
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if names.contains(&Symbol::intern("Copy")) {
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let meta = cx.meta_word(span, Symbol::intern("rustc_copy_clone_marker"));
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attrs.push(cx.attribute(span, meta));
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}
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});
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}
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