```
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'. 
```
{
    for (auto it = columns.begin(); it != columns.end();)
    {
        const auto * type_arr = typeid_cast<const DataTypeArray *>(it->type.get());
        if (!type_arr)
        {
            ++it;
            continue;
        }
        const auto * type_tuple = typeid_cast<const DataTypeTuple *>(type_arr->getNestedType().get());
        if (!type_tuple)
        {
            ++it;
            continue;
        }
        if (!type_tuple->haveExplicitNames())