$ cargo run Compiling panic v0.1.0 (file:///projects/panic) Finished dev [unoptimized + debuginfo] target(s) in 0.27s Running `target/debug/panic` thread 'main' panicked at 'index out of bounds: the len is 3 but the index is 99', src/main.rs:4:5 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace