{"ast_node_type":"variable","tokens":[{"end":56,"kind":"keyword","start":0,"text":"let"}]}
        let a = a.view().as_token_trees().flat_tokens();
    fn check_subtree_eq(a: &tt::TopSubtree, b: &tt::TopSubtree) -> bool {
        let b = b.view().as_token_trees().flat_tokens();