error: Invalid attribute parameter(s): 'Xname'. Expected 'name, returns, params'
 --> $DIR/attr-invalid-name-values.rs:5:2
  |
5 |       /// Returns a protocol version
  |  _____^
6 | |     #[rpc(Xname = "protocolVersion")]
7 | |     fn protocol_version(&self) -> Result<String>;
  | |_________________________________________________^