Kernel exit! has an optional argument

[noproblemwiththat]

Investigating a seemingly spurious Ruby::InsufficientPositionalArguments from steep, I think I find an incorrect signature for exit!, in the kernel source:

static VALUE
rb_f_exit_bang(int argc, VALUE *argv, VALUE obj)
{
    int istatus;

    if (rb_check_arity(argc, 0, 1) == 1) {
        istatus = exit_status_code(argv[0]);
    }
    else {
        istatus = EXIT_FAILURE;
    }
    _exit(istatus);

    UNREACHABLE_RETURN(Qnil);
}

but the signature requires an argument

  def self?.exit!: (Integer | TrueClass | FalseClass status) -> bot