```
$ ~/arc/build/clickhouse/programs/clickhouse client
ClickHouse client version 21.2.1.1-arcadia.
Connecting to localhost:9000 as user default.
Connected to ClickHouse server version 21.2.1 revision 54447.

max42-dev.sas.yp-c.yandex.net :) create table t(a Tuple(UInt8, UInt8)) engine = Log()

CREATE TABLE t
(
    `a` Tuple(UInt8, UInt8)
)
ENGINE = Log

Query id: b49dbb5d-d2a9-4c99-b90e-00c60edf2103

Ok.

0 rows in set. Elapsed: 0.005 sec. 

max42-dev.sas.yp-c.yandex.net :) insert into t values ((NULL, 42))

INSERT INTO t VALUES

Query id: 318d6f3e-f3bc-467c-85ff-62da908230dd

Logical error: 'Unexpected literal type inside Array: Nothing. It's a bug'.
Aborted (core dumped)
```

This is CH similar to one from Arcadia r7788360 (~fresh master version from GH).

(you don't have to strictly follow this form)

{
    WriteBufferFromOwnString res;
    const auto & nested_tuple = getNestedData();
    res << "Map(" << nested_tuple.getColumn(0).getName()
        << ", " << nested_tuple.getColumn(1).getName() << ")";
    return res.str();
}
ColumnMap::ColumnMap(MutableColumnPtr && nested_)
    : nested(std::move(nested_))
{
    const auto * column_array = typeid_cast<const ColumnArray *>(nested.get());
    if (!column_array)
        throw Exception(ErrorCodes::LOGICAL_ERROR, "ColumnMap can be created only from array of tuples");
    const auto * column_tuple = typeid_cast<const ColumnTuple *>(column_array->getDataPtr().get());
    if (!column_tuple)
        throw Exception(ErrorCodes::LOGICAL_ERROR, "ColumnMap can be created only from array of tuples");
    if (column_tuple->getColumns().size() != 2)
        throw Exception(ErrorCodes::LOGICAL_ERROR, "ColumnMap should contain only 2 subcolumns: keys and values");
    for (const auto & column : column_tuple->getColumns())
        if (isColumnConst(*column))
            throw Exception(ErrorCodes::ILLEGAL_COLUMN, "ColumnMap cannot have ColumnConst as its element");
}
MutableColumnPtr ColumnMap::cloneEmpty() const