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 (isDateTime64<Name, ToDataType>(arguments))
            {
                timezone_arg_position += 1;
                scale = static_cast<UInt32>(arguments[1].column->get64(0));
                if (to_datetime64 || scale != 0) 
                    return std::make_shared<DataTypeDateTime64>(scale,
                        extractTimeZoneNameFromFunctionArguments(arguments, timezone_arg_position, 0));
                return std::make_shared<DataTypeDateTime>(extractTimeZoneNameFromFunctionArguments(arguments, timezone_arg_position, 0));
            }
            if constexpr (std::is_same_v<ToDataType, DataTypeDateTime>)
                return std::make_shared<DataTypeDateTime>(extractTimeZoneNameFromFunctionArguments(arguments, timezone_arg_position, 0));
            else if constexpr (std::is_same_v<ToDataType, DataTypeDateTime64>)
                throw Exception("Unexpected branch in code of conversion function: it is a bug.", ErrorCodes::LOGICAL_ERROR);
            else
                return std::make_shared<ToDataType>();
        }
    }
    
    
    
    bool useDefaultImplementationForNulls() const override { return checked_return_type; }
    bool useDefaultImplementationForConstants() const override { return true; }
    ColumnNumbers getArgumentsThatAreAlwaysConstant() const override
    {
        if constexpr (std::is_same_v<ToDataType, DataTypeDateTime64>)
            return {2};
        return {1};
    }
    bool canBeExecutedOnDefaultArguments() const override { return false; }
    ColumnPtr executeImpl(const ColumnsWithTypeAndName & arguments, const DataTypePtr & result_type, size_t input_rows_count) const override