21.5.1
```sql

create table test(d Date, k Int64, s String) 
Engine=MergeTree partition by (toYYYYMM(d),k) order by (d, k)

insert into test values ('2020-01-01', 1, '');
insert into test values ('2020-01-02', 1, '');

SELECT * FROM test WHERE d != '2020-01-01'
0 rows in set. Elapsed: 0.003 sec.


SELECT * FROM test WHERE identity(d) !=  '2020-01-01';
┌──────────d─┬─k─┬─s─┐
│ 2020-01-02 │ 1 │   │
└────────────┴───┴───┘

SELECT * FROM test WHERE toDate(d) != '2020-01-01';
┌──────────d─┬─k─┬─s─┐
│ 2020-01-02 │ 1 │   │
└────────────┴───┴───┘
```

auto set_ast_hash = right_arg->getTreeHash();
        auto set_it = std::find_if(
            prepared_sets.begin(), prepared_sets.end(),
            [&](const auto & candidate_entry)
            {
                if (candidate_entry.first.ast_hash != set_ast_hash)
                    return false;
                for (size_t i = 0; i < indexes_mapping.size(); ++i)
                    if (!candidate_entry.second->areTypesEqual(indexes_mapping[i].tuple_index, data_types[i]))
                        return false;
                return true;
        });
        if (set_it == prepared_sets.end())
            return false;
        prepared_set = set_it->second;
    }
    
    if (!prepared_set->hasExplicitSetElements())
        return false;
    prepared_set->checkColumnsNumber(left_args_count);
    for (size_t i = 0; i < indexes_mapping.size(); ++i)
        prepared_set->checkTypesEqual(indexes_mapping[i].tuple_index, data_types[i]);
    out.set_index = std::make_shared<MergeTreeSetIndex>(prepared_set->getSetElements(), std::move(indexes_mapping));
    return true;
}
/** Allow to use two argument function with constant argument to be analyzed as a single argument function.
  * In other words, it performs "currying" (binding of arguments).
  * This is needed, for example, to support correct analysis of `toDate(time, 'UTC')`.
  */
class FunctionWithOptionalConstArg : public IFunctionBase