{"ast_node_type":"variable","tokens":[{"end":24,"kind":"keyword","start":0,"text":"let"}]}
    let impl_trait_ref =
    let trait_m = tcx.opt_associated_item(impl_m.trait_item_def_id.unwrap()).unwrap();
        tcx.impl_trait_ref(impl_m.impl_container(tcx).unwrap()).unwrap().instantiate_identity();