{"ast_node_type":"variable","tokens":[{"end":48,"kind":"keyword","start":0,"text":"let"}]}
    let mut item_tree = ctx.lower_block(&block);
    let ctx = lower::Ctx::new(db, loc.ast_id.file_id);
    let ItemTree { top_level, top_attrs, attrs, vis, big_data, small_data } = &item_tree;