static RuntimeException fail() {
    throw new RuntimeException("fail");
  }
  
  static RuntimeException fail(Object msg) {
    throw new RuntimeException(String.valueOf(msg));
  }
  
  static RuntimeException fail(S msg) {
    throw new RuntimeException(unnull(msg));
  }
   
  static RuntimeException fail(S msg, Throwable innerException) {
    throw new RuntimeException(msg, innerException);
  }
  
  // disabled for now to shorten some programs 
  /*static RuntimeException fail(S msg, O... args) {
    throw new RuntimeException(format(msg, args));
  }*/