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use fold instead of try_fold now that .by_ref().next() has been inlined
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the8472 committed Oct 11, 2021
1 parent a398b6b commit f1c588f
Showing 1 changed file with 6 additions and 13 deletions.
19 changes: 6 additions & 13 deletions library/core/src/array/iter.rs
Expand Up @@ -135,19 +135,12 @@ impl<T, const N: usize> Iterator for IntoIter<T, N> {
Fold: FnMut(Acc, Self::Item) -> Acc,
{
let data = &mut self.data;
// FIXME: This uses try_fold(&mut iter) instead of fold(iter) because the latter
// would go through the blanket `impl Iterator for &mut I` implementation
// which lacks inline annotations on its methods and adding those would be a larger
// perturbation than using try_fold here.
// Whether it would be beneficial to add those annotations should be investigated separately.
(&mut self.alive)
.try_fold::<_, _, Result<_, !>>(init, |acc, idx| {
// SAFETY: idx is obtained by folding over the `alive` range, which implies the
// value is currently considered alive but as the range is being consumed each value
// we read here will only be read once and then considered dead.
Ok(fold(acc, unsafe { data.get_unchecked(idx).assume_init_read() }))
})
.unwrap()
self.alive.by_ref().fold(init, |acc, idx| {
// SAFETY: idx is obtained by folding over the `alive` range, which implies the
// value is currently considered alive but as the range is being consumed each value
// we read here will only be read once and then considered dead.
fold(acc, unsafe { data.get_unchecked(idx).assume_init_read() })
})
}

fn count(self) -> usize {
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