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?
{
    ExtendedDayNum tmp(0);
    readDateText(tmp, rb);
    x = tmp;
}
template <>
inline void parseImpl<DataTypeDateTime>(DataTypeDateTime::FieldType & x, ReadBuffer & rb, const DateLUTImpl * time_zone)
{
    time_t time = 0;
    readDateTimeText(time, rb, *time_zone);
    convertFromTime<DataTypeDateTime>(x, time);
}
template <>
inline void parseImpl<DataTypeUUID>(DataTypeUUID::FieldType & x, ReadBuffer & rb, const DateLUTImpl *)
{
    UUID tmp;
    readUUIDText(tmp, rb);
    x = tmp.toUnderType();
}
template <typename DataType>
bool tryParseImpl(typename DataType::FieldType & x, ReadBuffer & rb, const DateLUTImpl *)
{
    if constexpr (std::is_floating_point_v<typename DataType::FieldType>)
        return tryReadFloatText(x, rb);
    else 
        return tryReadIntText(x, rb);
}
template <>
inline bool tryParseImpl<DataTypeDate>(DataTypeDate::FieldType & x, ReadBuffer & rb, const DateLUTImpl *)