Strange error in CHYT in case of improper sorted join usage

Suppose we have a table `//tmp/a` sorted by (x, y) and `//tmp/b` sorted by (y).

Then, the following query
```
SELECT
a.y
FROM
`//tmp/a` as a
LEFT JOIN
`//tmp/b` as b
ON a.y = b.y
```

fails with an error

```
Query 724938c1-d50bd0df-d08a8932-c69b527f failed[1]
Invalid sorted JOIN: key is empty[1]
```

This error is not very informative, is it possible to make it better?