{"ast_node_type":"variable","tokens":[{"end":40,"kind":"keyword","start":0,"text":"let"}]}
        let sym = nfc_normalize(string);
    fn normalize_and_validate_ident(&mut self, string: &str) -> Result<Self::Symbol, ()> {
        if rustc_lexer::is_ident(sym.as_str()) { Ok(sym) } else { Err(()) }