https://clickhouse-test-reports.s3.yandex.net/20492/c5b96a522e29b38eae3f6c2d945540dd234e3c34/fuzzer_msan/server.log

```
for i in {1..100}; do clickhouse-client --query "SELECT toUInt8(assumeNotNull(cast(cast(NULL, 'Nullable(String)'), 'Nullable(Enum8(\'Hello\' = 1))')))"; done

160
224
128
192
64
64
32
160
128
192
128
224
128
160
0
96
64
32
192
224
64
96
224
96
128
192
192
128
...
```
if (to_nullable && WhichDataType(from_type).isStringOrFixedString())
                done = callOnIndexAndDataType<ToDataType>(from_type->getTypeId(), call, ConvertReturnNullOnErrorTag{});
            else
                done = callOnIndexAndDataType<ToDataType>(from_type->getTypeId(), call, ConvertDefaultBehaviorTag{});
        }
        if (!done)
        {
            
            if (std::is_same_v<ToDataType, DataTypeString>)
            {
                return ConvertImplGenericToString::execute(arguments);
            }
            else
                throw Exception("Illegal type " + arguments[0].type->getName() + " of argument of function " + getName(),
                    ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
        }
        return result_column;
    }
};
/** Function toTOrZero (where T is number of date or datetime type):
  *  try to convert from String to type T through parsing,
  *  if cannot parse, return default value instead of throwing exception.
  * Function toTOrNull will return Nullable type with NULL when cannot parse.
  * NOTE Also need to implement tryToUnixTimestamp with timezone.
  */
template <typename ToDataType, typename Name,
    ConvertFromStringExceptionMode exception_mode,
    ConvertFromStringParsingMode parsing_mode = ConvertFromStringParsingMode::Normal>
class FunctionConvertFromString : public IFunction