{"ast_node_type":"variable","tokens":[{"end":75,"kind":"keyword","start":0,"text":"let"}]}
    let impl_ty_args = GenericArgs::identity_for_item(tcx, impl_ty.def_id);
    let impl_ty_def_id = impl_ty.def_id.expect_local();
    let rebased_args = impl_ty_args.rebase_onto(tcx, container_id, impl_trait_ref.args);