**Describe what's wrong**

```sql
SELECT toTypeName(s), toString(s) FROM
(
 SELECT toFixedString('',32) AS s 
 UNION ALL
 SELECT null AS s 
)
```

this query works in all versions from 19.17 to 21.8, but stop works after 21.9+ 

https://fiddle.clickhouse.com/7bd65b36-a6e6-470a-8bdc-4c98a33ff453
21.8 works

https://fiddle.clickhouse.com/9e40a424-4027-4c7f-bd41-b20935ae9129
21.9 doesn't work
```
Received exception from server (version 21.9.6):
Code: 44. DB::Exception: Received from localhost:9000. DB::Exception: Illegal column Nullable(FixedString(32)) of first argument of function toString. (ILLEGAL_COLUMN)
```

this query works in all versions

```sql
SELECT toTypeName(s), toString(s) FROM
(
 SELECT '' AS s 
 UNION ALL
 SELECT null AS s 
)
```
https://fiddle.clickhouse.com/4f810f03-1644-4eb7-b696-0341b1bbdbc4


**Does it reproduce on recent release?**
Yes, reproduce in all releases 21.9+
}
                    else
                    {
                        result_column = ConvertImpl<LeftDataType, RightDataType, FunctionName>::execute(
                            arguments, result_type, input_rows_count, AccurateOrNullConvertStrategyAdditions());
                    }
                    return true;
                }
                return false;
            });
            
            if (!res)
            {
                if (wrapper_cast_type == CastType::accurateOrNull)
                {
                    auto nullable_column_wrapper = FunctionCast<FunctionName>::createToNullableColumnWrapper();
                    return nullable_column_wrapper(arguments, result_type, column_nullable, input_rows_count);
                }
                else
                {
                    throw Exception(ErrorCodes::CANNOT_CONVERT_TYPE,
                        "Conversion from {} to {} is not supported",
                        from_type_index, to_type->getName());
                }
            }
            return result_column;
        };
    }
    template <typename ToDataType>
    WrapperType createBoolWrapper(const DataTypePtr & from_type, const ToDataType * const to_type, bool requested_result_is_nullable) const