{"ast_node_type":"variable","tokens":[{"end":61,"kind":"keyword","start":0,"text":"let"}]}
    let enclosing_fn_def_id = tcx.typeck_root_def_id(def_id);
    // Find the generics of the enclosing function, as defined in the source code.
    let generics = tcx.generics_of(enclosing_fn_def_id);