**How to reproduce**

CH version: `20.5.2 revision 54435` (latest on `apt` at the moment). Cannot reproduce on `20.4.5`, so it's a regression.

Table:

```sql
create table repro_hits (
    date Date,
    metric Float64
) engine=MergeTree() order by date
```

Query:

```sql
SELECT
    date as period,
    1 as having_check,
    min(date) as period_start,
    addDays(max(date), 1) as period_end,
    dateDiff('second', period_start, period_end) as total_duration,
    sum(metric) as metric_
FROM repro_hits
GROUP BY period
having having_check != -1
```

**Error message and/or stacktrace**
```
Received exception from server (version 20.5.2):
Code: 179. DB::Exception: Received from localhost:9000. DB::Exception: Different expressions with the same alias period_start:
min(date) AS period_start
and
date AS period_start
.
```

The error goes away if I opt out of optimization with `SETTINGS enable_optimize_predicate_expression = 0`.
{
    if (!select_query->limitBy())
        return;
    std::set<String> elems_set;
    ASTs & elems = select_query->limitBy()->children;
    ASTs unique_elems;
    unique_elems.reserve(elems.size());
    for (const auto & elem : elems)
    {
        if (elems_set.emplace(elem->getColumnName()).second)
            unique_elems.emplace_back(elem);
    }
    if (unique_elems.size() < elems.size())
        elems = std::move(unique_elems);
}
void optimizeUsing(const ASTSelectQuery * select_query)