rustc_parse/parser/
cfg_select.rs

1use rustc_ast::tokenstream::{TokenStream, TokenTree};
2use rustc_ast::util::classify;
3use rustc_ast::{AttrKind, token};
4use rustc_errors::PResult;
5use rustc_span::Span;
6
7use crate::exp;
8use crate::parser::{AttrWrapper, ForceCollect, Parser, Restrictions, Trailing, UsePreAttrPos};
9
10#[derive(#[automatically_derived]
impl ::core::default::Default for CfgSelectBranchAttrSpans {
    #[inline]
    fn default() -> CfgSelectBranchAttrSpans {
        CfgSelectBranchAttrSpans {
            attrs: ::core::default::Default::default(),
            doc_comments: ::core::default::Default::default(),
        }
    }
}Default)]
11pub struct CfgSelectBranchAttrSpans {
12    pub attrs: Vec<Span>,
13    pub doc_comments: Vec<Span>,
14}
15
16impl<'a> Parser<'a> {
17    /// Parses the right-hand side of a `cfg_select!` branch,
18    /// which can be either a braced block or an expression.
19    pub fn parse_cfg_select_branch_rhs(&mut self) -> PResult<'a, TokenStream> {
20        if self.token == token::OpenBrace {
21            // Strip the outer '{' and '}'.
22            match self.parse_token_tree() {
23                TokenTree::Token(..) => {
    ::core::panicking::panic_fmt(format_args!("internal error: entered unreachable code: {0}",
            format_args!("because the current token is a \'{{\'")));
}unreachable!("because the current token is a '{{'"),
24                TokenTree::Delimited(.., tts) => {
25                    // Optionally end with a comma.
26                    let _ = self.eat(crate::parser::token_type::ExpTokenPair {
    tok: rustc_ast::token::Comma,
    token_type: crate::parser::token_type::TokenType::Comma,
}exp!(Comma));
27                    return Ok(tts);
28                }
29            }
30        }
31        let attrs = AttrWrapper::empty(); // FIXME expressions with attributes can be supported here
32        let expr = self.collect_tokens(
33            None,
34            AttrWrapper::empty(),
35            ForceCollect::Yes,
36            |p, _empty_attrs| {
37                p.parse_expr_res_after_attrs(Restrictions::STMT_EXPR, attrs)
38                    .map(|(expr, _)| (expr, Trailing::No, UsePreAttrPos::No))
39            },
40        )?;
41        if !classify::expr_is_complete(&expr)
42            && self.token != token::CloseBrace
43            && self.token != token::Eof
44        {
45            self.expect(crate::parser::token_type::ExpTokenPair {
    tok: rustc_ast::token::Comma,
    token_type: crate::parser::token_type::TokenType::Comma,
}exp!(Comma))?;
46        } else {
47            let _ = self.eat(crate::parser::token_type::ExpTokenPair {
    tok: rustc_ast::token::Comma,
    token_type: crate::parser::token_type::TokenType::Comma,
}exp!(Comma));
48        }
49        Ok(TokenStream::from_ast(&expr))
50    }
51
52    /// Parses outer attributes before a `cfg_select!` branch for recovery.
53    pub fn parse_cfg_select_branch_outer_attrs(
54        &mut self,
55    ) -> PResult<'a, Option<CfgSelectBranchAttrSpans>> {
56        let attrs = self.parse_outer_attributes()?;
57        if attrs.is_empty() {
58            return Ok(None);
59        }
60
61        let mut spans = CfgSelectBranchAttrSpans::default();
62        for attr in attrs.take_for_recovery(self.psess) {
63            match attr.kind {
64                AttrKind::Normal(..) => spans.attrs.push(attr.span),
65                AttrKind::Synthetic(..) => ::core::panicking::panic("internal error: entered unreachable code")unreachable!(),
66                // `parse_outer_attributes` already emitted E0753 for inner doc comments before
67                // recovering them as outer doc-comment attributes.
68                AttrKind::DocComment(comment_kind, _)
69                    if self.span_to_snippet(attr.span).ok().is_some_and(
70                        |snippet| match comment_kind {
71                            token::CommentKind::Line => snippet.starts_with("//!"),
72                            token::CommentKind::Block => snippet.starts_with("/*!"),
73                        },
74                    ) => {}
75                AttrKind::DocComment(..) => spans.doc_comments.push(attr.span),
76            }
77        }
78
79        Ok(Some(spans))
80    }
81}
rustc_parse/parser/cfg_select.rs

rustc_parse/parser/
cfg_select.rs
