Auto merge of #84130 - Aaron1011:fix/none-delim-lookahead, r=petrochenkov
Fix lookahead with None-delimited group
Fixes https://github.com/rust-lang/rust/issues/84162, a regression introduced by https://github.com/rust-lang/rust/pull/82608.
diff --git a/compiler/rustc_parse/src/parser/mod.rs b/compiler/rustc_parse/src/parser/mod.rs
index 4b97c8b..ed95a56 100644
--- a/compiler/rustc_parse/src/parser/mod.rs
+++ b/compiler/rustc_parse/src/parser/mod.rs
@@ -930,15 +930,38 @@
}
let frame = &self.token_cursor.frame;
- match frame.tree_cursor.look_ahead(dist - 1) {
- Some(tree) => match tree {
- TokenTree::Token(token) => looker(token),
- TokenTree::Delimited(dspan, delim, _) => {
- looker(&Token::new(token::OpenDelim(*delim), dspan.open))
- }
- },
- None => looker(&Token::new(token::CloseDelim(frame.delim), frame.span.close)),
+ if frame.delim != DelimToken::NoDelim {
+ let all_normal = (0..dist).all(|i| {
+ let token = frame.tree_cursor.look_ahead(i);
+ !matches!(token, Some(TokenTree::Delimited(_, DelimToken::NoDelim, _)))
+ });
+ if all_normal {
+ return match frame.tree_cursor.look_ahead(dist - 1) {
+ Some(tree) => match tree {
+ TokenTree::Token(token) => looker(token),
+ TokenTree::Delimited(dspan, delim, _) => {
+ looker(&Token::new(token::OpenDelim(*delim), dspan.open))
+ }
+ },
+ None => looker(&Token::new(token::CloseDelim(frame.delim), frame.span.close)),
+ };
+ }
}
+
+ let mut cursor = self.token_cursor.clone();
+ let mut i = 0;
+ let mut token = Token::dummy();
+ while i < dist {
+ token = cursor.next().0;
+ if matches!(
+ token.kind,
+ token::OpenDelim(token::NoDelim) | token::CloseDelim(token::NoDelim)
+ ) {
+ continue;
+ }
+ i += 1;
+ }
+ return looker(&token);
}
/// Returns whether any of the given keywords are `dist` tokens ahead of the current one.
diff --git a/src/test/ui/macros/none-delim-lookahead.rs b/src/test/ui/macros/none-delim-lookahead.rs
new file mode 100644
index 0000000..bf4fddea
--- /dev/null
+++ b/src/test/ui/macros/none-delim-lookahead.rs
@@ -0,0 +1,15 @@
+// check-pass
+
+macro_rules! make_struct {
+ ($name:ident) => {
+ #[derive(Debug)]
+ struct Foo {
+ #[cfg(not(FALSE))]
+ field: fn($name: bool)
+ }
+ }
+}
+
+make_struct!(param_name);
+
+fn main() {}
