The tracking issue for this feature is: #23121

See also advanced_slice_patterns.

If you want to match against a slice or array, you can use & with the slice_patterns feature:

#![feature(slice_patterns)]

fn main() {
    let v = vec!["match_this", "1"];

    match &v[..] {
        &["match_this", second] => println!("The second element is {}", second),
        _ => {},
    }
}