Could not force a panic with arrays without adding a trait

[tjarratt]

Hello, I'd like to thank you for all the hard work that has gone into building this codebase. I've been telling myself for years now that I should learn rust, and with your help I've just started to write my first rust code. There's a lot I still don't know about rust, so this issue may be very naive.

After installing rust version 1.45.0 I began working through the koans until I got to arrays.rs which has a test to cause a panic with an invalid array index, as you can see below :

// Attempting to access an array at an index that is
// out of its bounds will cause an error. Let's cause
// that error in this example.
#[test]
#[should_panic]
#[allow(const_err)]
fn out_of_index() {
    let arr: [&'static str; 5] = ["rust", "is", "mostly", "for", "nerds"];
    arr[__];
}

However, I was unable to make this pass by simply using an invalid index such as 6. With a little bit of googling I was able to find out that you can add a trait to allow for unconditional panics.

// Attempting to access an array at an index that is
// out of its bounds will cause an error. Let's cause
// that error in this example.
#[test]
#[should_panic]
#[allow(const_err)]
#[alllow(unconditional_panic)] // <<<< this is the line I needed to add
fn out_of_index() {
    let arr: [&'static str; 5] = ["rust", "is", "mostly", "for", "nerds"];
    arr[666];
}

It seems like one of the following is true

• I don't fully understand this koan
• the trait [allow(const_err)] should be changed to #[alllow(unconditional_panic)]

If the second is true I would be more than happy to issue you a pull request.

[gentooza]

Also, const_err seems to be deprecated now rust-lang/rust#71800

[yrmo]

Thank you also ran into this issue, just in case anyone else copies and pastes this like me:

• Remove the #[allow(const_err)] line
• Typo in #[alllow(unconditional_panic)] should be allow