**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
                                    throw Exception("Unexpected inf or nan to integer conversion", ErrorCodes::CANNOT_CONVERT_TYPE);
                            }
                        }
                        if constexpr (std::is_same_v<Additions, AccurateOrNullConvertStrategyAdditions>
                                || std::is_same_v<Additions, AccurateConvertStrategyAdditions>)
                        {
                            bool convert_result = accurate::convertNumeric(vec_from[i], vec_to[i]);
                            if (!convert_result)
                            {
                                if (std::is_same_v<Additions, AccurateOrNullConvertStrategyAdditions>)
                                {
                                    vec_to[i] = 0;
                                    (*vec_null_map_to)[i] = true;
                                }
                                else
                                {
                                    throw Exception(
                                        "Value in column " + named_from.column->getName() + " cannot be safely converted into type "
                                            + result_type->getName(),
                                        ErrorCodes::CANNOT_CONVERT_TYPE);
                                }
                            }
                        }
                        else
                        {
                            vec_to[i] = static_cast<ToFieldType>(vec_from[i]);
                        }
                    }