diff options
Diffstat (limited to 'compiler/rustc_parse/src/parser/item.rs')
| -rw-r--r-- | compiler/rustc_parse/src/parser/item.rs | 53 |
1 files changed, 44 insertions, 9 deletions
diff --git a/compiler/rustc_parse/src/parser/item.rs b/compiler/rustc_parse/src/parser/item.rs index e93fb2473fb..20833a0f70f 100644 --- a/compiler/rustc_parse/src/parser/item.rs +++ b/compiler/rustc_parse/src/parser/item.rs @@ -1290,12 +1290,24 @@ impl<'a> Parser<'a> { } fn is_unsafe_foreign_mod(&self) -> bool { - self.token.is_keyword(kw::Unsafe) - && self.is_keyword_ahead(1, &[kw::Extern]) - && self.look_ahead( - 2 + self.look_ahead(2, |t| t.can_begin_string_literal() as usize), - |t| *t == token::OpenDelim(Delimiter::Brace), - ) + // Look for `unsafe`. + if !self.token.is_keyword(kw::Unsafe) { + return false; + } + // Look for `extern`. + if !self.is_keyword_ahead(1, &[kw::Extern]) { + return false; + } + + // Look for the optional ABI string literal. + let n = if self.look_ahead(2, |t| t.can_begin_string_literal()) { 3 } else { 2 }; + + // Look for the `{`. Use `tree_look_ahead` because the ABI (if present) + // might be a metavariable i.e. an invisible-delimited sequence, and + // `tree_look_ahead` will consider that a single element when looking + // ahead. + self.tree_look_ahead(n, |t| matches!(t, TokenTree::Delimited(_, _, Delimiter::Brace, _))) + == Some(true) } fn is_static_global(&mut self) -> bool { @@ -2604,13 +2616,36 @@ impl<'a> Parser<'a> { }) // `extern ABI fn` || self.check_keyword_case(exp!(Extern), case) + // Use `tree_look_ahead` because `ABI` might be a metavariable, + // i.e. an invisible-delimited sequence, and `tree_look_ahead` + // will consider that a single element when looking ahead. && self.look_ahead(1, |t| t.can_begin_string_literal()) - && (self.look_ahead(2, |t| t.is_keyword_case(kw::Fn, case)) || + && (self.tree_look_ahead(2, |tt| { + match tt { + TokenTree::Token(t, _) => t.is_keyword_case(kw::Fn, case), + TokenTree::Delimited(..) => false, + } + }) == Some(true) || // This branch is only for better diagnostics; `pub`, `unsafe`, etc. are not // allowed here. (self.may_recover() - && self.look_ahead(2, |t| ALL_QUALS.iter().any(|exp| t.is_keyword(exp.kw))) - && self.look_ahead(3, |t| t.is_keyword_case(kw::Fn, case)))) + && self.tree_look_ahead(2, |tt| { + match tt { + TokenTree::Token(t, _) => + ALL_QUALS.iter().any(|exp| { + t.is_keyword(exp.kw) + }), + TokenTree::Delimited(..) => false, + } + }) == Some(true) + && self.tree_look_ahead(3, |tt| { + match tt { + TokenTree::Token(t, _) => t.is_keyword_case(kw::Fn, case), + TokenTree::Delimited(..) => false, + } + }) == Some(true) + ) + ) } /// Parses all the "front matter" (or "qualifiers") for a `fn` declaration, |