{"ast_node_type":"variable","tokens":[{"end":57,"kind":"keyword","start":0,"text":"let"}]}
    let gen_args = vec![GenericArg::Type(alt_self_type)];
    // Add the impl blocks for `DispatchFromDyn` and `CoerceUnsized`.
    add_impl_block(impl_generics.clone(), sym::DispatchFromDyn, gen_args.clone());