```
SELECT version()
─version()─┐
│ 21.8.5.7  │
└───────────┘
```
We have a request, as a result of which we get an array.
When getting an item using a computed value, there is no value
```
SELECT
    arrayMap(x -> x, [[1], [2], [3]]) AS x,
    toTypeName(x),
    x[3 - 2] AS y,
    x[toInt64(1)] AS yy,
    x[toUInt8(1)] AS yyy

┌─x─────────────┬─toTypeName(arrayMap(lambda(tuple(x), x), [[1], [2], [3]]))─┬─y──┬─yy─┬─yyy─┐
│ [[1],[2],[3]] │ Array(Array(UInt8))                                        │ [] │ [] │ [1] │
└───────────────┴────────────────────────────────────────────────────────────┴────┴────┴─────┘
```
However, when the array is explicitly specified, the value is present.
The types are the same.
```
SELECT
    [[1], [2], [3]] AS x,
    toTypeName(x),
    x[3 - 2] AS y,
    x[toInt64(1)] AS yy,
    x[toInt8(1)] AS yyy

┌─x─────────────┬─toTypeName([[1], [2], [3]])─┬─y───┬─yy──┬─yyy─┐
│ [[1],[2],[3]] │ Array(Array(UInt8))         │ [1] │ [1] │ [1] │
└───────────────┴─────────────────────────────┴─────┴─────┴─────┘
```


ArrayImpl::NullMapBuilder & builder, size_t input_rows_count) const
{
    ColumnPtr res;
    if ((res = executeTuple(arguments, input_rows_count)))
        return res;
    else if (!isColumnConst(*arguments[1].column))
    {
        if (!((res = executeArgument<UInt8>(arguments, result_type, builder, input_rows_count))
            || (res = executeArgument<UInt16>(arguments, result_type, builder, input_rows_count))
            || (res = executeArgument<UInt32>(arguments, result_type, builder, input_rows_count))
            || (res = executeArgument<UInt64>(arguments, result_type, builder, input_rows_count))
            || (res = executeArgument<Int8>(arguments, result_type, builder, input_rows_count))
            || (res = executeArgument<Int16>(arguments, result_type, builder, input_rows_count))
            || (res = executeArgument<Int32>(arguments, result_type, builder, input_rows_count))
            || (res = executeArgument<Int64>(arguments, result_type, builder, input_rows_count))))
        throw Exception("Second argument for function " + getName() + " must have UInt or Int type.",
                        ErrorCodes::ILLEGAL_COLUMN);
    }
    else