**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+
{
    UUID tmp;
    if (!tryReadUUIDText(tmp, rb))
        return false;
    x = tmp.toUnderType();
    return true;
}
/** Throw exception with verbose message when string value is not parsed completely.
  */
[[noreturn]] inline void throwExceptionForIncompletelyParsedValue(ReadBuffer & read_buffer, const IDataType & result_type)
{
    WriteBufferFromOwnString message_buf;
    message_buf << "Cannot parse string " << quote << String(read_buffer.buffer().begin(), read_buffer.buffer().size())
                << " as " << result_type.getName()
                << ": syntax error";
    if (read_buffer.offset())
        message_buf << " at position " << read_buffer.offset()
                    << " (parsed just " << quote << String(read_buffer.buffer().begin(), read_buffer.offset()) << ")";
    else
        message_buf << " at begin of string";
    
    if (isNativeNumber(result_type) && !(result_type.getName() == "IPv4" || result_type.getName() == "IPv6"))
        message_buf << ". Note: there are to" << result_type.getName() << "OrZero and to" << result_type.getName() << "OrNull functions, which returns zero/NULL instead of throwing exception.";
    throw Exception(message_buf.str(), ErrorCodes::CANNOT_PARSE_TEXT);
}
enum class ConvertFromStringExceptionMode