Beginner here.

Look at following code:

`fn main() { let x: u8 = 255; println!("The value of x is {}.", x + 1); }`

Result is panic message.

My question is:

The range of **x** in this case should be from 0 ~ 255.

**x** is defined. But I haven’t defined **x + 1**

What about the range of **x + 1** ? The same as **x** ?

I am asking because if the code is like this

```
fn main() {
let mut x: u8 = 255;
x = x + 1;
println!("The value of x is {}.", x);
}
```

Then I can understand it.