I expect it should work:
```
:) select CAST(CAST('{"x" : 1}', 'Object(\'json\')'), 'Object(Nullable(\'json\'))')

SELECT CAST(CAST('{"x" : 1}', 'Object(\'json\')'), 'Object(Nullable(\'json\'))')

Query id: fb057b45-b72a-4d22-9b38-a3136cdf2465


0 rows in set. Elapsed: 0.002 sec.

Received exception from server (version 22.5.1):
Code: 53. DB::Exception: Received from localhost:9000. DB::Exception: Cast to Object can be performed only from flatten named Tuple, Map or String. Got: Object('json'): While processing CAST(CAST('{"x" : 1}', 'Object(\'json\')'), 'Object(Nullable(\'json\'))'). (TYPE_MISMATCH)
```

@CurtizJ what do you think?
}
                        }
                        else
                        {
                            if constexpr (IsDataTypeDecimal<FromDataType> && IsDataTypeDecimal<ToDataType>)
                                vec_to[i] = convertDecimals<FromDataType, ToDataType>(vec_from[i], col_from->getScale(), col_to->getScale());
                            else if constexpr (IsDataTypeDecimal<FromDataType> && IsDataTypeNumber<ToDataType>)
                                vec_to[i] = convertFromDecimal<FromDataType, ToDataType>(vec_from[i], col_from->getScale());
                            else if constexpr (IsDataTypeNumber<FromDataType> && IsDataTypeDecimal<ToDataType>)
                                vec_to[i] = convertToDecimal<FromDataType, ToDataType>(vec_from[i], col_to->getScale());
                            else
                                throw Exception("Unsupported data type in conversion function", ErrorCodes::CANNOT_CONVERT_TYPE);
                        }
                    }
                    else
                    {
                        
                        if constexpr (std::is_floating_point_v<FromFieldType> && !std::is_floating_point_v<ToFieldType>)
                        {
                            if (!isFinite(vec_from[i]))
                            {
                                if constexpr (std::is_same_v<Additions, AccurateOrNullConvertStrategyAdditions>)
                                {
                                    vec_to[i] = 0;
                                    (*vec_null_map_to)[i] = true;
                                    continue;
                                }
                                else
                                    throw Exception("Unexpected inf or nan to integer conversion", ErrorCodes::CANNOT_CONVERT_TYPE);
                            }