```
CREATE TABLE a
(
    `number` UInt64,
    `x` MATERIALIZED x
)
ENGINE = MergeTree
ORDER BY number;
-- that should fail!

insert into a values (1);
Received exception from server (version 21.7.1):
Code: 47. DB::Exception: Received from localhost:9000. DB::Exception: Missing columns: 'x' while processing query: 'CAST(x, 'UInt8') AS x', required columns: 'x' 'x'. 
```
{
            ++it;
            continue;
        }
        ColumnDescription column = std::move(*it);
        removeSubcolumns(column.name, column.type);
        it = columns.get<0>().erase(it);
        const DataTypes & elements = type_tuple->getElements();
        const Strings & names = type_tuple->getElementNames();
        size_t tuple_size = elements.size();
        for (size_t i = 0; i < tuple_size; ++i)
        {
            auto nested_column = column;
            
            nested_column.name = Nested::concatenateName(column.name, names[i]);
            nested_column.type = std::make_shared<DataTypeArray>(elements[i]);
            addSubcolumns(nested_column.name, nested_column.type);
            columns.get<0>().insert(it, std::move(nested_column));
        }
    }
}
NamesAndTypesList ColumnsDescription::getOrdinary() const
{
    NamesAndTypesList ret;
    for (const auto & col : columns)
        if (col.default_desc.kind == ColumnDefaultKind::Default)
            ret.emplace_back(col.name, col.type);
    return ret;
}
NamesAndTypesList ColumnsDescription::getMaterialized() const