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?
}
            return createTupleToMapWrapper(from_kv_types, to_kv_types);
        }
        else if (const auto * from_array = typeid_cast<const DataTypeArray *>(from_type_untyped.get()))
        {
            const auto * nested_tuple = typeid_cast<const DataTypeTuple *>(from_array->getNestedType().get());
            if (!nested_tuple || nested_tuple->getElements().size() != 2)
                throw Exception{"CAST AS Map from array requeires nested tuple of 2 elements.\n"
                    "Left type: " + from_array->getName() + ", right type: " + to_type->getName(), ErrorCodes::TYPE_MISMATCH};
            return createArrayToMapWrrapper(nested_tuple->getElements(), to_type->getKeyValueTypes());
        }
        else if (const auto * from_type = checkAndGetDataType<DataTypeMap>(from_type_untyped.get()))
        {
            return createMapToMapWrrapper(from_type->getKeyValueTypes(), to_type->getKeyValueTypes());
        }
        else
        {
            throw Exception{"Unsupported types to CAST AS Map\n"
                "Left type: " + from_type_untyped->getName() + ", right type: " + to_type->getName(), ErrorCodes::TYPE_MISMATCH};
        }
    }
    WrapperType createTupleToObjectWrapper(const DataTypeTuple & from_tuple, bool has_nullable_subcolumns) const
    {
        if (!from_tuple.haveExplicitNames())
            throw Exception(ErrorCodes::TYPE_MISMATCH,
            "Cast to Object can be performed only from flatten Named Tuple. Got: {}", from_tuple.getName());
        PathsInData paths;
        DataTypes from_types;
        std::tie(paths, from_types) = flattenTuple(from_tuple.getPtr());
        auto to_types = from_types;