numeric.c:147
VALUE
rb_num_coerce_relop(x, y)
    VALUE x, y;
{
    VALUE c, x0 = x, y0 = y;

    if (!do_coerce(&x, &y, Qfalse) ||
	NIL_P(c = rb_funcall(x, ruby_frame->orig_func, 1, y))) {
	rb_cmperr(x0, y0);
	return Qnil;		/* not reached */
    }
    return c;
}
