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//@ run-pass
#![feature(deref_patterns)]
#![allow(incomplete_features)]
fn simple_vec(vec: Vec<u32>) -> u32 {
match vec {
deref!([]) => 100,
deref!([x]) if x == 4 => x + 4,
deref!([x]) => x,
deref!([1, x]) => x + 200,
deref!(ref slice) => slice.iter().sum(),
_ => 2000,
}
}
fn nested_vec(vecvec: Vec<Vec<u32>>) -> u32 {
match vecvec {
deref!([]) => 0,
deref!([deref!([x])]) => x,
deref!([deref!([0, x]) | deref!([1, x])]) => x,
deref!([ref x]) => x.iter().sum(),
deref!([deref!([]), deref!([1, x, y])]) => y - x,
_ => 2000,
}
}
fn ref_mut(val: u32) -> u32 {
let mut b = Box::new(0u32);
match &mut b {
deref!(_x) if false => unreachable!(),
deref!(x) => {
*x = val;
}
_ => unreachable!(),
}
let deref!(x) = &b else { unreachable!() };
*x
}
#[rustfmt::skip]
fn or_and_guard(tuple: (u32, u32)) -> u32 {
let mut sum = 0;
let b = Box::new(tuple);
match b {
deref!((x, _) | (_, x)) if { sum += x; false } => {},
_ => {},
}
sum
}
fn main() {
assert_eq!(simple_vec(vec![1]), 1);
assert_eq!(simple_vec(vec![1, 2]), 202);
assert_eq!(simple_vec(vec![1, 2, 3]), 6);
assert_eq!(simple_vec(vec![4]), 8);
assert_eq!(nested_vec(vec![vec![0, 42]]), 42);
assert_eq!(nested_vec(vec![vec![1, 42]]), 42);
assert_eq!(nested_vec(vec![vec![1, 2, 3]]), 6);
assert_eq!(nested_vec(vec![vec![], vec![1, 2, 3]]), 1);
assert_eq!(ref_mut(42), 42);
assert_eq!(or_and_guard((10, 32)), 42);
}
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