rust/tests/ui/pattern/usefulness/match-slice-patterns.rs

fn check(list: &[Option<()>]) {
    match list {
    //~^ ERROR `&[_, Some(_), .., None, _]` not covered
        &[] => {},
        &[_] => {},
        &[_, _] => {},
        &[_, None, ..] => {},
        &[.., Some(_), _] => {},
    }
}

fn main() {}
_match: correct max_slice_length logic The logic used to be wildly wrong, but before the HAIR patch its wrongness was hidden by another bug. Fixes #37598. 2016-11-05 13:32:35 +02:00			`fn check(list: &[Option<()>]) {`
			`match list {`
Use VarLenSlice consistently when splitting constructors The previous behaviour ignored slice lengths above a certain length because it could not do otherwise. We now have VarLenSlice however, that can represent the ignored lengths to make the algorithm more consistent. This does not change the correctness of the algorithm, but makes it easier to reason about. As a nice side-effect, exhaustiveness errors have improved: they now capture all missing lengths instead of only the shortest. 2019-11-05 16:30:04 +00:00			//~^ ERROR `&[_, Some(_), .., None, _]` not covered
_match: correct max_slice_length logic The logic used to be wildly wrong, but before the HAIR patch its wrongness was hidden by another bug. Fixes #37598. 2016-11-05 13:32:35 +02:00			`&[] => {},`
			`&[_] => {},`
			`&[_, _] => {},`
			`&[_, None, ..] => {},`
			`&[.., Some(_), _] => {},`
			`}`
			`}`

			`fn main() {}`