{"ast_node_type":"other","tokens":[{"end":86,"kind":"keyword","start":0,"text":"//"}]}
            // Disallow `'fn`, but with a better error message than `expect_lifetime`.
        if let Some((ident, is_raw)) = self.token.lifetime() {
            if matches!(is_raw, IdentIsRaw::No) && ident.without_first_quote().is_reserved() {