Auto merge of #138515 - petrochenkov:cfgtrace, r= · rust-lang/rust@c78b933 (original) (raw)
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`//! Conditional compilation stripping.
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use std::iter;
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`use rustc_ast::ptr::P;
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`use rustc_ast::token::{Delimiter, Token, TokenKind};
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`use rustc_ast::tokenstream::{
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`AttrTokenStream, AttrTokenTree, LazyAttrTokenStream, Spacing, TokenTree,
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`};
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`use rustc_ast::{
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self as ast, AttrStyle, Attribute, HasAttrs, HasTokens, MetaItem, MetaItemInner, NodeId,
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self as ast, AttrKind, AttrStyle, Attribute, HasAttrs, HasTokens, MetaItem, MetaItemInner,
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NodeId, NormalAttr,
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`};
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`use rustc_attr_parsing as attr;
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`use rustc_data_structures::flat_map_in_place::FlatMapInPlace;
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`@@ -275,10 +278,23 @@ impl<'a> StripUnconfigured<'a> {
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`pub(crate) fn expand_cfg_attr(&self, cfg_attr: &Attribute, recursive: bool) -> Vec {
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` validate_attr::check_attribute_safety(&self.sess.psess, AttributeSafety::Normal, &cfg_attr);
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// A trace attribute left in AST in place of the original cfg_attr attribute.
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// It can later be used by lints or other diagnostics.
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let mut trace_attr = cfg_attr.clone();
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match &mut trace_attr.kind {
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AttrKind::Normal(normal) => {
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let NormalAttr { item, tokens } = &mut **normal;
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item.path.segments[0].ident.name = sym::cfg_attr_trace;
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// This makes the trace attributes unobservable to token-based proc macros.
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*tokens = Some(LazyAttrTokenStream::new(AttrTokenStream::default()));
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}
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AttrKind::DocComment(..) => unreachable!(),
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}
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`let Some((cfg_predicate, expanded_attrs)) =
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` rustc_parse::parse_cfg_attr(cfg_attr, &self.sess.psess)
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`else {
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return vec![];
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return vec![trace_attr];
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`};
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``
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`// Lint on zero attributes in source.
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`}
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`if !attr::cfg_matches(&cfg_predicate, &self.sess, self.lint_node_id, self.features) {
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return vec![];
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return vec![trace_attr];
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`}
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`if recursive {
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`` // We call process_cfg_attr recursively in case there's a
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`` // cfg_attr inside of another cfg_attr. E.g.
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`` // #[cfg_attr(false, cfg_attr(true, some_attr))].
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expanded_attrs
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let expanded_attrs = expanded_attrs
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`.into_iter()
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.flat_map(|item| self.process_cfg_attr(&self.expand_cfg_attr_item(cfg_attr, item)))
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.collect()
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.flat_map(|item| self.process_cfg_attr(&self.expand_cfg_attr_item(cfg_attr, item)));
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iter::once(trace_attr).chain(expanded_attrs).collect()
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`} else {
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expanded_attrs
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.into_iter()
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.map(|item| self.expand_cfg_attr_item(cfg_attr, item))
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.collect()
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let expanded_attrs =
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expanded_attrs.into_iter().map(|item| self.expand_cfg_attr_item(cfg_attr, item));
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iter::once(trace_attr).chain(expanded_attrs).collect()
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`}
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`}
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``