thread 'main' panicked at 'index out of bounds: the len is 5 but the index is 5'

[markgras]

I am currently working through the Rust By Example collection. On the Arrays and Slices page, the last line of the example is supposed to cause an "index out of bounds" compile error when un-commented, but this does not happen. Instead, the code compiles with no error and a thread 'main' panicked at 'index out of bounds: the len is 5 but the index is 5' error shows up at runtime.

Here is a shortened version of this example that erroneously compiles:

fn main() {
    let xs: [i32; 5] = [1, 2, 3, 4, 5];
    for i in 0..xs.len() + 1 {
        match xs.get(i) {
            Some(xval) => println!("{}: {}", i, xval),
            None => println!("Slow down! {} is too far!", i),
        }
    }
    println!("{}", xs[5]);
}

If you remove the for loop then the compiler properly complains. This problem occurs with both the latest stable (1.64.0) and nightly versions. Because this issue exists with nightly, I do not think that it is the same as #103385. Nightly information is given below.

Meta

rustc --version --verbose:

rustc 1.64.0 (a55dd71d5 2022-09-19)
binary: rustc                                        
commit-hash: a55dd71d5fb0ec5a6a3a9e8c27b2127ba491ce52
commit-date: 2022-09-19                              
host: x86_64-pc-windows-msvc                         
release: 1.64.0                                      
LLVM version: 14.0.6 

Backtrace

thread 'main' panicked at 'index out of bounds: the len is 5 but the index is 5', main.rs:9:20
stack backtrace:
   0: std::panicking::begin_panic_handler
             at /rustc/a55dd71d5fb0ec5a6a3a9e8c27b2127ba491ce52/library\std\src\panicking.rs:584
   1: core::panicking::panic_fmt
             at /rustc/a55dd71d5fb0ec5a6a3a9e8c27b2127ba491ce52/library\core\src\panicking.rs:142
   2: core::panicking::panic_bounds_check
             at /rustc/a55dd71d5fb0ec5a6a3a9e8c27b2127ba491ce52/library\core\src\panicking.rs:84
   3: core::fmt::Arguments::new_v1
   4: core::ops::function::FnOnce::call_once
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.

[markgras]

I apologize. Although nightly was installed, it was not my default toolchain (hence why the meta version above is stable). This issue is solved in nightly, so it likely is the same as #103385. I will go ahead and close this issue. Again, I apologize for the spam.