slice pattern bug

[mind-zz]

The following program prints 102. Commenting out the match arm for either 100 or 102 causes the correct value (101) to be printed. I believe the first and third cases are being merged as they have the same form (but different guards), ruining the priority.

#![feature(slice_patterns)]

fn main() {
    let v = vec![1, 2];
    println!("{}", test(&v));
}

fn test(a: &[u64]) -> u64 {
    match a {
        [a, b ..]  if a == 3  => 100,
        [a, b]     if a == 1  => 101,
        [a, b ..]             => 102,
        _                     => 103
    }
}
// rustc 1.1.0-dev (69e47c77b 2015-04-23) (built 2015-04-23)

[mind-zz]

I'm actually seeing similar behavior even without guards (rest pattern overriding an earlier fixed-arity pattern).

[jfirebaugh]

Seems to be working as expected now: https://play.rust-lang.org/?gist=2de1a5847481016cfe1909c6b24634f9&version=nightly&backtrace=0

[arielb1]

Sure. Bug never existed in MIR.