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// Checks for issue #26235
fn main() {
use std::thread;
type Key = u32;
const NUM_THREADS: usize = 2;
#[derive(Clone, Copy)]
struct Stats<S> {
upsert: S,
delete: S,
insert: S,
update: S,
};
impl<S> Stats<S>
where
S: Copy,
{
fn dot<B, F, T>(self, s: Stats<T>, f: F) -> Stats<B>
where
F: Fn(S, T) -> B,
{
let Stats { upsert: u1, delete: d1, insert: i1, update: p1 } = self;
let Stats { upsert: u2, delete: d2, insert: i2, update: p2 } = s;
Stats { upsert: f(u1, u2), delete: f(d1, d2), insert: f(i1, i2), update: f(p1, p2) }
}
fn new(init: S) -> Self {
Stats { upsert: init, delete: init, insert: init, update: init }
}
}
fn make_threads() -> Vec<thread::JoinHandle<()>> {
let mut t = Vec::with_capacity(NUM_THREADS);
for _ in 0..NUM_THREADS {
t.push(thread::spawn(move || {}));
}
t
}
let stats = [Stats::new(0); NUM_THREADS];
make_threads();
{
let Stats { ref upsert, ref delete, ref insert, ref update } = stats
.iter()
.fold(Stats::new(0), |res, &s| res.dot(s, |x: Key, y: Key| x.wrapping_add(y)));
println!(
"upserts: {}, deletes: {}, inserts: {}, updates: {}",
upsert, delete, insert, update
);
}
}
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