hash.c:825
static int
rb_hash_search_value(key, value, data)
    VALUE key, value, *data;
{
    if (key == Qundef) return ST_CONTINUE;
    if (rb_equal(value, data[1])) {
	data[0] = Qtrue;
	return ST_STOP;
    }
    return ST_CONTINUE;
}
