{"ast_node_type":"variable","tokens":[{"end":84,"kind":"keyword","start":0,"text":"let"}]}
        let Left(statement) = self.body.stmt_at(candidate.location) else { bug!() };
    fn validate_candidate(&mut self, candidate: Candidate) -> Result<(), Unpromotable> {
        let Some((_, Rvalue::Ref(_, kind, place))) = statement.kind.as_assign() else { bug!() };