{"ast_node_type":"variable","tokens":[{"end":83,"kind":"keyword","start":0,"text":"let"}]}
    let fn_body_id = hir_node.body_id().expect("HIR node is a function with body");
    let hir_node = tcx.hir_node_by_def_id(def_id);
    let hir_body = tcx.hir_body(fn_body_id);