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-rw-r--r--library/core/tests/slice.rs2597
1 files changed, 2597 insertions, 0 deletions
diff --git a/library/core/tests/slice.rs b/library/core/tests/slice.rs
new file mode 100644
index 000000000..0656109e9
--- /dev/null
+++ b/library/core/tests/slice.rs
@@ -0,0 +1,2597 @@
+use core::cell::Cell;
+use core::cmp::Ordering;
+use core::mem::MaybeUninit;
+use core::result::Result::{Err, Ok};
+use core::slice;
+
+#[test]
+fn test_position() {
+ let b = [1, 2, 3, 5, 5];
+ assert_eq!(b.iter().position(|&v| v == 9), None);
+ assert_eq!(b.iter().position(|&v| v == 5), Some(3));
+ assert_eq!(b.iter().position(|&v| v == 3), Some(2));
+ assert_eq!(b.iter().position(|&v| v == 0), None);
+}
+
+#[test]
+fn test_rposition() {
+ let b = [1, 2, 3, 5, 5];
+ assert_eq!(b.iter().rposition(|&v| v == 9), None);
+ assert_eq!(b.iter().rposition(|&v| v == 5), Some(4));
+ assert_eq!(b.iter().rposition(|&v| v == 3), Some(2));
+ assert_eq!(b.iter().rposition(|&v| v == 0), None);
+}
+
+#[test]
+fn test_binary_search() {
+ let b: [i32; 0] = [];
+ assert_eq!(b.binary_search(&5), Err(0));
+
+ let b = [4];
+ assert_eq!(b.binary_search(&3), Err(0));
+ assert_eq!(b.binary_search(&4), Ok(0));
+ assert_eq!(b.binary_search(&5), Err(1));
+
+ let b = [1, 2, 4, 6, 8, 9];
+ assert_eq!(b.binary_search(&5), Err(3));
+ assert_eq!(b.binary_search(&6), Ok(3));
+ assert_eq!(b.binary_search(&7), Err(4));
+ assert_eq!(b.binary_search(&8), Ok(4));
+
+ let b = [1, 2, 4, 5, 6, 8];
+ assert_eq!(b.binary_search(&9), Err(6));
+
+ let b = [1, 2, 4, 6, 7, 8, 9];
+ assert_eq!(b.binary_search(&6), Ok(3));
+ assert_eq!(b.binary_search(&5), Err(3));
+ assert_eq!(b.binary_search(&8), Ok(5));
+
+ let b = [1, 2, 4, 5, 6, 8, 9];
+ assert_eq!(b.binary_search(&7), Err(5));
+ assert_eq!(b.binary_search(&0), Err(0));
+
+ let b = [1, 3, 3, 3, 7];
+ assert_eq!(b.binary_search(&0), Err(0));
+ assert_eq!(b.binary_search(&1), Ok(0));
+ assert_eq!(b.binary_search(&2), Err(1));
+ assert!(match b.binary_search(&3) {
+ Ok(1..=3) => true,
+ _ => false,
+ });
+ assert!(match b.binary_search(&3) {
+ Ok(1..=3) => true,
+ _ => false,
+ });
+ assert_eq!(b.binary_search(&4), Err(4));
+ assert_eq!(b.binary_search(&5), Err(4));
+ assert_eq!(b.binary_search(&6), Err(4));
+ assert_eq!(b.binary_search(&7), Ok(4));
+ assert_eq!(b.binary_search(&8), Err(5));
+
+ let b = [(); usize::MAX];
+ assert_eq!(b.binary_search(&()), Ok(usize::MAX / 2));
+}
+
+#[test]
+fn test_binary_search_by_overflow() {
+ let b = [(); usize::MAX];
+ assert_eq!(b.binary_search_by(|_| Ordering::Equal), Ok(usize::MAX / 2));
+ assert_eq!(b.binary_search_by(|_| Ordering::Greater), Err(0));
+ assert_eq!(b.binary_search_by(|_| Ordering::Less), Err(usize::MAX));
+}
+
+#[test]
+// Test implementation specific behavior when finding equivalent elements.
+// It is ok to break this test but when you do a crater run is highly advisable.
+fn test_binary_search_implementation_details() {
+ let b = [1, 1, 2, 2, 3, 3, 3];
+ assert_eq!(b.binary_search(&1), Ok(1));
+ assert_eq!(b.binary_search(&2), Ok(3));
+ assert_eq!(b.binary_search(&3), Ok(5));
+ let b = [1, 1, 1, 1, 1, 3, 3, 3, 3];
+ assert_eq!(b.binary_search(&1), Ok(4));
+ assert_eq!(b.binary_search(&3), Ok(7));
+ let b = [1, 1, 1, 1, 3, 3, 3, 3, 3];
+ assert_eq!(b.binary_search(&1), Ok(2));
+ assert_eq!(b.binary_search(&3), Ok(4));
+}
+
+#[test]
+fn test_partition_point() {
+ let b: [i32; 0] = [];
+ assert_eq!(b.partition_point(|&x| x < 5), 0);
+
+ let b = [4];
+ assert_eq!(b.partition_point(|&x| x < 3), 0);
+ assert_eq!(b.partition_point(|&x| x < 4), 0);
+ assert_eq!(b.partition_point(|&x| x < 5), 1);
+
+ let b = [1, 2, 4, 6, 8, 9];
+ assert_eq!(b.partition_point(|&x| x < 5), 3);
+ assert_eq!(b.partition_point(|&x| x < 6), 3);
+ assert_eq!(b.partition_point(|&x| x < 7), 4);
+ assert_eq!(b.partition_point(|&x| x < 8), 4);
+
+ let b = [1, 2, 4, 5, 6, 8];
+ assert_eq!(b.partition_point(|&x| x < 9), 6);
+
+ let b = [1, 2, 4, 6, 7, 8, 9];
+ assert_eq!(b.partition_point(|&x| x < 6), 3);
+ assert_eq!(b.partition_point(|&x| x < 5), 3);
+ assert_eq!(b.partition_point(|&x| x < 8), 5);
+
+ let b = [1, 2, 4, 5, 6, 8, 9];
+ assert_eq!(b.partition_point(|&x| x < 7), 5);
+ assert_eq!(b.partition_point(|&x| x < 0), 0);
+
+ let b = [1, 3, 3, 3, 7];
+ assert_eq!(b.partition_point(|&x| x < 0), 0);
+ assert_eq!(b.partition_point(|&x| x < 1), 0);
+ assert_eq!(b.partition_point(|&x| x < 2), 1);
+ assert_eq!(b.partition_point(|&x| x < 3), 1);
+ assert_eq!(b.partition_point(|&x| x < 4), 4);
+ assert_eq!(b.partition_point(|&x| x < 5), 4);
+ assert_eq!(b.partition_point(|&x| x < 6), 4);
+ assert_eq!(b.partition_point(|&x| x < 7), 4);
+ assert_eq!(b.partition_point(|&x| x < 8), 5);
+}
+
+#[test]
+fn test_iterator_advance_by() {
+ let v = &[0, 1, 2, 3, 4];
+
+ for i in 0..=v.len() {
+ let mut iter = v.iter();
+ iter.advance_by(i).unwrap();
+ assert_eq!(iter.as_slice(), &v[i..]);
+ }
+
+ let mut iter = v.iter();
+ assert_eq!(iter.advance_by(v.len() + 1), Err(v.len()));
+ assert_eq!(iter.as_slice(), &[]);
+
+ let mut iter = v.iter();
+ iter.advance_by(3).unwrap();
+ assert_eq!(iter.as_slice(), &v[3..]);
+ iter.advance_by(2).unwrap();
+ assert_eq!(iter.as_slice(), &[]);
+ iter.advance_by(0).unwrap();
+}
+
+#[test]
+fn test_iterator_advance_back_by() {
+ let v = &[0, 1, 2, 3, 4];
+
+ for i in 0..=v.len() {
+ let mut iter = v.iter();
+ iter.advance_back_by(i).unwrap();
+ assert_eq!(iter.as_slice(), &v[..v.len() - i]);
+ }
+
+ let mut iter = v.iter();
+ assert_eq!(iter.advance_back_by(v.len() + 1), Err(v.len()));
+ assert_eq!(iter.as_slice(), &[]);
+
+ let mut iter = v.iter();
+ iter.advance_back_by(3).unwrap();
+ assert_eq!(iter.as_slice(), &v[..v.len() - 3]);
+ iter.advance_back_by(2).unwrap();
+ assert_eq!(iter.as_slice(), &[]);
+ iter.advance_back_by(0).unwrap();
+}
+
+#[test]
+fn test_iterator_nth() {
+ let v: &[_] = &[0, 1, 2, 3, 4];
+ for i in 0..v.len() {
+ assert_eq!(v.iter().nth(i).unwrap(), &v[i]);
+ }
+ assert_eq!(v.iter().nth(v.len()), None);
+
+ let mut iter = v.iter();
+ assert_eq!(iter.nth(2).unwrap(), &v[2]);
+ assert_eq!(iter.nth(1).unwrap(), &v[4]);
+}
+
+#[test]
+fn test_iterator_nth_back() {
+ let v: &[_] = &[0, 1, 2, 3, 4];
+ for i in 0..v.len() {
+ assert_eq!(v.iter().nth_back(i).unwrap(), &v[v.len() - i - 1]);
+ }
+ assert_eq!(v.iter().nth_back(v.len()), None);
+
+ let mut iter = v.iter();
+ assert_eq!(iter.nth_back(2).unwrap(), &v[2]);
+ assert_eq!(iter.nth_back(1).unwrap(), &v[0]);
+}
+
+#[test]
+fn test_iterator_last() {
+ let v: &[_] = &[0, 1, 2, 3, 4];
+ assert_eq!(v.iter().last().unwrap(), &4);
+ assert_eq!(v[..1].iter().last().unwrap(), &0);
+}
+
+#[test]
+fn test_iterator_count() {
+ let v: &[_] = &[0, 1, 2, 3, 4];
+ assert_eq!(v.iter().count(), 5);
+
+ let mut iter2 = v.iter();
+ iter2.next();
+ iter2.next();
+ assert_eq!(iter2.count(), 3);
+}
+
+#[test]
+fn test_chunks_count() {
+ let v: &[i32] = &[0, 1, 2, 3, 4, 5];
+ let c = v.chunks(3);
+ assert_eq!(c.count(), 2);
+
+ let v2: &[i32] = &[0, 1, 2, 3, 4];
+ let c2 = v2.chunks(2);
+ assert_eq!(c2.count(), 3);
+
+ let v3: &[i32] = &[];
+ let c3 = v3.chunks(2);
+ assert_eq!(c3.count(), 0);
+}
+
+#[test]
+fn test_chunks_nth() {
+ let v: &[i32] = &[0, 1, 2, 3, 4, 5];
+ let mut c = v.chunks(2);
+ assert_eq!(c.nth(1).unwrap(), &[2, 3]);
+ assert_eq!(c.next().unwrap(), &[4, 5]);
+
+ let v2: &[i32] = &[0, 1, 2, 3, 4];
+ let mut c2 = v2.chunks(3);
+ assert_eq!(c2.nth(1).unwrap(), &[3, 4]);
+ assert_eq!(c2.next(), None);
+}
+
+#[test]
+fn test_chunks_next() {
+ let v = [0, 1, 2, 3, 4, 5];
+ let mut c = v.chunks(2);
+ assert_eq!(c.next().unwrap(), &[0, 1]);
+ assert_eq!(c.next().unwrap(), &[2, 3]);
+ assert_eq!(c.next().unwrap(), &[4, 5]);
+ assert_eq!(c.next(), None);
+
+ let v = [0, 1, 2, 3, 4, 5, 6, 7];
+ let mut c = v.chunks(3);
+ assert_eq!(c.next().unwrap(), &[0, 1, 2]);
+ assert_eq!(c.next().unwrap(), &[3, 4, 5]);
+ assert_eq!(c.next().unwrap(), &[6, 7]);
+ assert_eq!(c.next(), None);
+}
+
+#[test]
+fn test_chunks_next_back() {
+ let v = [0, 1, 2, 3, 4, 5];
+ let mut c = v.chunks(2);
+ assert_eq!(c.next_back().unwrap(), &[4, 5]);
+ assert_eq!(c.next_back().unwrap(), &[2, 3]);
+ assert_eq!(c.next_back().unwrap(), &[0, 1]);
+ assert_eq!(c.next_back(), None);
+
+ let v = [0, 1, 2, 3, 4, 5, 6, 7];
+ let mut c = v.chunks(3);
+ assert_eq!(c.next_back().unwrap(), &[6, 7]);
+ assert_eq!(c.next_back().unwrap(), &[3, 4, 5]);
+ assert_eq!(c.next_back().unwrap(), &[0, 1, 2]);
+ assert_eq!(c.next_back(), None);
+}
+
+#[test]
+fn test_chunks_nth_back() {
+ let v: &[i32] = &[0, 1, 2, 3, 4, 5];
+ let mut c = v.chunks(2);
+ assert_eq!(c.nth_back(1).unwrap(), &[2, 3]);
+ assert_eq!(c.next().unwrap(), &[0, 1]);
+ assert_eq!(c.next(), None);
+
+ let v2: &[i32] = &[0, 1, 2, 3, 4];
+ let mut c2 = v2.chunks(3);
+ assert_eq!(c2.nth_back(1).unwrap(), &[0, 1, 2]);
+ assert_eq!(c2.next(), None);
+ assert_eq!(c2.next_back(), None);
+
+ let v3: &[i32] = &[0, 1, 2, 3, 4];
+ let mut c3 = v3.chunks(10);
+ assert_eq!(c3.nth_back(0).unwrap(), &[0, 1, 2, 3, 4]);
+ assert_eq!(c3.next(), None);
+
+ let v4: &[i32] = &[0, 1, 2];
+ let mut c4 = v4.chunks(10);
+ assert_eq!(c4.nth_back(1_000_000_000usize), None);
+}
+
+#[test]
+fn test_chunks_last() {
+ let v: &[i32] = &[0, 1, 2, 3, 4, 5];
+ let c = v.chunks(2);
+ assert_eq!(c.last().unwrap()[1], 5);
+
+ let v2: &[i32] = &[0, 1, 2, 3, 4];
+ let c2 = v2.chunks(2);
+ assert_eq!(c2.last().unwrap()[0], 4);
+}
+
+#[test]
+fn test_chunks_zip() {
+ let v1: &[i32] = &[0, 1, 2, 3, 4];
+ let v2: &[i32] = &[6, 7, 8, 9, 10];
+
+ let res = v1
+ .chunks(2)
+ .zip(v2.chunks(2))
+ .map(|(a, b)| a.iter().sum::<i32>() + b.iter().sum::<i32>())
+ .collect::<Vec<_>>();
+ assert_eq!(res, vec![14, 22, 14]);
+}
+
+#[test]
+fn test_chunks_mut_count() {
+ let v: &mut [i32] = &mut [0, 1, 2, 3, 4, 5];
+ let c = v.chunks_mut(3);
+ assert_eq!(c.count(), 2);
+
+ let v2: &mut [i32] = &mut [0, 1, 2, 3, 4];
+ let c2 = v2.chunks_mut(2);
+ assert_eq!(c2.count(), 3);
+
+ let v3: &mut [i32] = &mut [];
+ let c3 = v3.chunks_mut(2);
+ assert_eq!(c3.count(), 0);
+}
+
+#[test]
+fn test_chunks_mut_nth() {
+ let v: &mut [i32] = &mut [0, 1, 2, 3, 4, 5];
+ let mut c = v.chunks_mut(2);
+ assert_eq!(c.nth(1).unwrap(), &[2, 3]);
+ assert_eq!(c.next().unwrap(), &[4, 5]);
+
+ let v2: &mut [i32] = &mut [0, 1, 2, 3, 4];
+ let mut c2 = v2.chunks_mut(3);
+ assert_eq!(c2.nth(1).unwrap(), &[3, 4]);
+ assert_eq!(c2.next(), None);
+}
+
+#[test]
+fn test_chunks_mut_nth_back() {
+ let v: &mut [i32] = &mut [0, 1, 2, 3, 4, 5];
+ let mut c = v.chunks_mut(2);
+ assert_eq!(c.nth_back(1).unwrap(), &[2, 3]);
+ assert_eq!(c.next().unwrap(), &[0, 1]);
+
+ let v1: &mut [i32] = &mut [0, 1, 2, 3, 4];
+ let mut c1 = v1.chunks_mut(3);
+ assert_eq!(c1.nth_back(1).unwrap(), &[0, 1, 2]);
+ assert_eq!(c1.next(), None);
+
+ let v3: &mut [i32] = &mut [0, 1, 2, 3, 4];
+ let mut c3 = v3.chunks_mut(10);
+ assert_eq!(c3.nth_back(0).unwrap(), &[0, 1, 2, 3, 4]);
+ assert_eq!(c3.next(), None);
+
+ let v4: &mut [i32] = &mut [0, 1, 2];
+ let mut c4 = v4.chunks_mut(10);
+ assert_eq!(c4.nth_back(1_000_000_000usize), None);
+}
+
+#[test]
+fn test_chunks_mut_last() {
+ let v: &mut [i32] = &mut [0, 1, 2, 3, 4, 5];
+ let c = v.chunks_mut(2);
+ assert_eq!(c.last().unwrap(), &[4, 5]);
+
+ let v2: &mut [i32] = &mut [0, 1, 2, 3, 4];
+ let c2 = v2.chunks_mut(2);
+ assert_eq!(c2.last().unwrap(), &[4]);
+}
+
+#[test]
+fn test_chunks_mut_zip() {
+ let v1: &mut [i32] = &mut [0, 1, 2, 3, 4];
+ let v2: &[i32] = &[6, 7, 8, 9, 10];
+
+ for (a, b) in v1.chunks_mut(2).zip(v2.chunks(2)) {
+ let sum = b.iter().sum::<i32>();
+ for v in a {
+ *v += sum;
+ }
+ }
+ assert_eq!(v1, [13, 14, 19, 20, 14]);
+}
+
+#[test]
+fn test_chunks_mut_zip_aliasing() {
+ let v1: &mut [i32] = &mut [0, 1, 2, 3, 4];
+ let v2: &[i32] = &[6, 7, 8, 9, 10];
+
+ let mut it = v1.chunks_mut(2).zip(v2.chunks(2));
+ let first = it.next().unwrap();
+ let _ = it.next().unwrap();
+ assert_eq!(first, (&mut [0, 1][..], &[6, 7][..]));
+}
+
+#[test]
+fn test_chunks_exact_mut_zip_aliasing() {
+ let v1: &mut [i32] = &mut [0, 1, 2, 3, 4];
+ let v2: &[i32] = &[6, 7, 8, 9, 10];
+
+ let mut it = v1.chunks_exact_mut(2).zip(v2.chunks(2));
+ let first = it.next().unwrap();
+ let _ = it.next().unwrap();
+ assert_eq!(first, (&mut [0, 1][..], &[6, 7][..]));
+}
+
+#[test]
+fn test_rchunks_mut_zip_aliasing() {
+ let v1: &mut [i32] = &mut [0, 1, 2, 3, 4];
+ let v2: &[i32] = &[6, 7, 8, 9, 10];
+
+ let mut it = v1.rchunks_mut(2).zip(v2.chunks(2));
+ let first = it.next().unwrap();
+ let _ = it.next().unwrap();
+ assert_eq!(first, (&mut [3, 4][..], &[6, 7][..]));
+}
+
+#[test]
+fn test_rchunks_exact_mut_zip_aliasing() {
+ let v1: &mut [i32] = &mut [0, 1, 2, 3, 4];
+ let v2: &[i32] = &[6, 7, 8, 9, 10];
+
+ let mut it = v1.rchunks_exact_mut(2).zip(v2.chunks(2));
+ let first = it.next().unwrap();
+ let _ = it.next().unwrap();
+ assert_eq!(first, (&mut [3, 4][..], &[6, 7][..]));
+}
+
+#[test]
+fn test_chunks_exact_count() {
+ let v: &[i32] = &[0, 1, 2, 3, 4, 5];
+ let c = v.chunks_exact(3);
+ assert_eq!(c.count(), 2);
+
+ let v2: &[i32] = &[0, 1, 2, 3, 4];
+ let c2 = v2.chunks_exact(2);
+ assert_eq!(c2.count(), 2);
+
+ let v3: &[i32] = &[];
+ let c3 = v3.chunks_exact(2);
+ assert_eq!(c3.count(), 0);
+}
+
+#[test]
+fn test_chunks_exact_nth() {
+ let v: &[i32] = &[0, 1, 2, 3, 4, 5];
+ let mut c = v.chunks_exact(2);
+ assert_eq!(c.nth(1).unwrap(), &[2, 3]);
+ assert_eq!(c.next().unwrap(), &[4, 5]);
+
+ let v2: &[i32] = &[0, 1, 2, 3, 4, 5, 6];
+ let mut c2 = v2.chunks_exact(3);
+ assert_eq!(c2.nth(1).unwrap(), &[3, 4, 5]);
+ assert_eq!(c2.next(), None);
+}
+
+#[test]
+fn test_chunks_exact_nth_back() {
+ let v: &[i32] = &[0, 1, 2, 3, 4, 5];
+ let mut c = v.chunks_exact(2);
+ assert_eq!(c.nth_back(1).unwrap(), &[2, 3]);
+ assert_eq!(c.next().unwrap(), &[0, 1]);
+ assert_eq!(c.next(), None);
+
+ let v2: &[i32] = &[0, 1, 2, 3, 4];
+ let mut c2 = v2.chunks_exact(3);
+ assert_eq!(c2.nth_back(0).unwrap(), &[0, 1, 2]);
+ assert_eq!(c2.next(), None);
+ assert_eq!(c2.next_back(), None);
+
+ let v3: &[i32] = &[0, 1, 2, 3, 4];
+ let mut c3 = v3.chunks_exact(10);
+ assert_eq!(c3.nth_back(0), None);
+}
+
+#[test]
+fn test_chunks_exact_last() {
+ let v: &[i32] = &[0, 1, 2, 3, 4, 5];
+ let c = v.chunks_exact(2);
+ assert_eq!(c.last().unwrap(), &[4, 5]);
+
+ let v2: &[i32] = &[0, 1, 2, 3, 4];
+ let c2 = v2.chunks_exact(2);
+ assert_eq!(c2.last().unwrap(), &[2, 3]);
+}
+
+#[test]
+fn test_chunks_exact_remainder() {
+ let v: &[i32] = &[0, 1, 2, 3, 4];
+ let c = v.chunks_exact(2);
+ assert_eq!(c.remainder(), &[4]);
+}
+
+#[test]
+fn test_chunks_exact_zip() {
+ let v1: &[i32] = &[0, 1, 2, 3, 4];
+ let v2: &[i32] = &[6, 7, 8, 9, 10];
+
+ let res = v1
+ .chunks_exact(2)
+ .zip(v2.chunks_exact(2))
+ .map(|(a, b)| a.iter().sum::<i32>() + b.iter().sum::<i32>())
+ .collect::<Vec<_>>();
+ assert_eq!(res, vec![14, 22]);
+}
+
+#[test]
+fn test_chunks_exact_mut_count() {
+ let v: &mut [i32] = &mut [0, 1, 2, 3, 4, 5];
+ let c = v.chunks_exact_mut(3);
+ assert_eq!(c.count(), 2);
+
+ let v2: &mut [i32] = &mut [0, 1, 2, 3, 4];
+ let c2 = v2.chunks_exact_mut(2);
+ assert_eq!(c2.count(), 2);
+
+ let v3: &mut [i32] = &mut [];
+ let c3 = v3.chunks_exact_mut(2);
+ assert_eq!(c3.count(), 0);
+}
+
+#[test]
+fn test_chunks_exact_mut_nth() {
+ let v: &mut [i32] = &mut [0, 1, 2, 3, 4, 5];
+ let mut c = v.chunks_exact_mut(2);
+ assert_eq!(c.nth(1).unwrap(), &[2, 3]);
+ assert_eq!(c.next().unwrap(), &[4, 5]);
+
+ let v2: &mut [i32] = &mut [0, 1, 2, 3, 4, 5, 6];
+ let mut c2 = v2.chunks_exact_mut(3);
+ assert_eq!(c2.nth(1).unwrap(), &[3, 4, 5]);
+ assert_eq!(c2.next(), None);
+}
+
+#[test]
+fn test_chunks_exact_mut_nth_back() {
+ let v: &mut [i32] = &mut [0, 1, 2, 3, 4, 5];
+ let mut c = v.chunks_exact_mut(2);
+ assert_eq!(c.nth_back(1).unwrap(), &[2, 3]);
+ assert_eq!(c.next().unwrap(), &[0, 1]);
+ assert_eq!(c.next(), None);
+
+ let v2: &mut [i32] = &mut [0, 1, 2, 3, 4];
+ let mut c2 = v2.chunks_exact_mut(3);
+ assert_eq!(c2.nth_back(0).unwrap(), &[0, 1, 2]);
+ assert_eq!(c2.next(), None);
+ assert_eq!(c2.next_back(), None);
+
+ let v3: &mut [i32] = &mut [0, 1, 2, 3, 4];
+ let mut c3 = v3.chunks_exact_mut(10);
+ assert_eq!(c3.nth_back(0), None);
+}
+
+#[test]
+fn test_chunks_exact_mut_last() {
+ let v: &mut [i32] = &mut [0, 1, 2, 3, 4, 5];
+ let c = v.chunks_exact_mut(2);
+ assert_eq!(c.last().unwrap(), &[4, 5]);
+
+ let v2: &mut [i32] = &mut [0, 1, 2, 3, 4];
+ let c2 = v2.chunks_exact_mut(2);
+ assert_eq!(c2.last().unwrap(), &[2, 3]);
+}
+
+#[test]
+fn test_chunks_exact_mut_remainder() {
+ let v: &mut [i32] = &mut [0, 1, 2, 3, 4];
+ let c = v.chunks_exact_mut(2);
+ assert_eq!(c.into_remainder(), &[4]);
+}
+
+#[test]
+fn test_chunks_exact_mut_zip() {
+ let v1: &mut [i32] = &mut [0, 1, 2, 3, 4];
+ let v2: &[i32] = &[6, 7, 8, 9, 10];
+
+ for (a, b) in v1.chunks_exact_mut(2).zip(v2.chunks_exact(2)) {
+ let sum = b.iter().sum::<i32>();
+ for v in a {
+ *v += sum;
+ }
+ }
+ assert_eq!(v1, [13, 14, 19, 20, 4]);
+}
+
+#[test]
+fn test_array_chunks_infer() {
+ let v: &[i32] = &[0, 1, 2, 3, 4, -4];
+ let c = v.array_chunks();
+ for &[a, b, c] in c {
+ assert_eq!(a + b + c, 3);
+ }
+
+ let v2: &[i32] = &[0, 1, 2, 3, 4, 5, 6];
+ let total = v2.array_chunks().map(|&[a, b]| a * b).sum::<i32>();
+ assert_eq!(total, 2 * 3 + 4 * 5);
+}
+
+#[test]
+fn test_array_chunks_count() {
+ let v: &[i32] = &[0, 1, 2, 3, 4, 5];
+ let c = v.array_chunks::<3>();
+ assert_eq!(c.count(), 2);
+
+ let v2: &[i32] = &[0, 1, 2, 3, 4];
+ let c2 = v2.array_chunks::<2>();
+ assert_eq!(c2.count(), 2);
+
+ let v3: &[i32] = &[];
+ let c3 = v3.array_chunks::<2>();
+ assert_eq!(c3.count(), 0);
+}
+
+#[test]
+fn test_array_chunks_nth() {
+ let v: &[i32] = &[0, 1, 2, 3, 4, 5];
+ let mut c = v.array_chunks::<2>();
+ assert_eq!(c.nth(1).unwrap(), &[2, 3]);
+ assert_eq!(c.next().unwrap(), &[4, 5]);
+
+ let v2: &[i32] = &[0, 1, 2, 3, 4, 5, 6];
+ let mut c2 = v2.array_chunks::<3>();
+ assert_eq!(c2.nth(1).unwrap(), &[3, 4, 5]);
+ assert_eq!(c2.next(), None);
+}
+
+#[test]
+fn test_array_chunks_nth_back() {
+ let v: &[i32] = &[0, 1, 2, 3, 4, 5];
+ let mut c = v.array_chunks::<2>();
+ assert_eq!(c.nth_back(1).unwrap(), &[2, 3]);
+ assert_eq!(c.next().unwrap(), &[0, 1]);
+ assert_eq!(c.next(), None);
+
+ let v2: &[i32] = &[0, 1, 2, 3, 4];
+ let mut c2 = v2.array_chunks::<3>();
+ assert_eq!(c2.nth_back(0).unwrap(), &[0, 1, 2]);
+ assert_eq!(c2.next(), None);
+ assert_eq!(c2.next_back(), None);
+
+ let v3: &[i32] = &[0, 1, 2, 3, 4];
+ let mut c3 = v3.array_chunks::<10>();
+ assert_eq!(c3.nth_back(0), None);
+}
+
+#[test]
+fn test_array_chunks_last() {
+ let v: &[i32] = &[0, 1, 2, 3, 4, 5];
+ let c = v.array_chunks::<2>();
+ assert_eq!(c.last().unwrap(), &[4, 5]);
+
+ let v2: &[i32] = &[0, 1, 2, 3, 4];
+ let c2 = v2.array_chunks::<2>();
+ assert_eq!(c2.last().unwrap(), &[2, 3]);
+}
+
+#[test]
+fn test_array_chunks_remainder() {
+ let v: &[i32] = &[0, 1, 2, 3, 4];
+ let c = v.array_chunks::<2>();
+ assert_eq!(c.remainder(), &[4]);
+}
+
+#[test]
+fn test_array_chunks_zip() {
+ let v1: &[i32] = &[0, 1, 2, 3, 4];
+ let v2: &[i32] = &[6, 7, 8, 9, 10];
+
+ let res = v1
+ .array_chunks::<2>()
+ .zip(v2.array_chunks::<2>())
+ .map(|(a, b)| a.iter().sum::<i32>() + b.iter().sum::<i32>())
+ .collect::<Vec<_>>();
+ assert_eq!(res, vec![14, 22]);
+}
+
+#[test]
+fn test_array_chunks_mut_infer() {
+ let v: &mut [i32] = &mut [0, 1, 2, 3, 4, 5, 6];
+ for a in v.array_chunks_mut() {
+ let sum = a.iter().sum::<i32>();
+ *a = [sum; 3];
+ }
+ assert_eq!(v, &[3, 3, 3, 12, 12, 12, 6]);
+
+ let v2: &mut [i32] = &mut [0, 1, 2, 3, 4, 5, 6];
+ v2.array_chunks_mut().for_each(|[a, b]| core::mem::swap(a, b));
+ assert_eq!(v2, &[1, 0, 3, 2, 5, 4, 6]);
+}
+
+#[test]
+fn test_array_chunks_mut_count() {
+ let v: &mut [i32] = &mut [0, 1, 2, 3, 4, 5];
+ let c = v.array_chunks_mut::<3>();
+ assert_eq!(c.count(), 2);
+
+ let v2: &mut [i32] = &mut [0, 1, 2, 3, 4];
+ let c2 = v2.array_chunks_mut::<2>();
+ assert_eq!(c2.count(), 2);
+
+ let v3: &mut [i32] = &mut [];
+ let c3 = v3.array_chunks_mut::<2>();
+ assert_eq!(c3.count(), 0);
+}
+
+#[test]
+fn test_array_chunks_mut_nth() {
+ let v: &mut [i32] = &mut [0, 1, 2, 3, 4, 5];
+ let mut c = v.array_chunks_mut::<2>();
+ assert_eq!(c.nth(1).unwrap(), &[2, 3]);
+ assert_eq!(c.next().unwrap(), &[4, 5]);
+
+ let v2: &mut [i32] = &mut [0, 1, 2, 3, 4, 5, 6];
+ let mut c2 = v2.array_chunks_mut::<3>();
+ assert_eq!(c2.nth(1).unwrap(), &[3, 4, 5]);
+ assert_eq!(c2.next(), None);
+}
+
+#[test]
+fn test_array_chunks_mut_nth_back() {
+ let v: &mut [i32] = &mut [0, 1, 2, 3, 4, 5];
+ let mut c = v.array_chunks_mut::<2>();
+ assert_eq!(c.nth_back(1).unwrap(), &[2, 3]);
+ assert_eq!(c.next().unwrap(), &[0, 1]);
+ assert_eq!(c.next(), None);
+
+ let v2: &mut [i32] = &mut [0, 1, 2, 3, 4];
+ let mut c2 = v2.array_chunks_mut::<3>();
+ assert_eq!(c2.nth_back(0).unwrap(), &[0, 1, 2]);
+ assert_eq!(c2.next(), None);
+ assert_eq!(c2.next_back(), None);
+
+ let v3: &mut [i32] = &mut [0, 1, 2, 3, 4];
+ let mut c3 = v3.array_chunks_mut::<10>();
+ assert_eq!(c3.nth_back(0), None);
+}
+
+#[test]
+fn test_array_chunks_mut_last() {
+ let v: &mut [i32] = &mut [0, 1, 2, 3, 4, 5];
+ let c = v.array_chunks_mut::<2>();
+ assert_eq!(c.last().unwrap(), &[4, 5]);
+
+ let v2: &mut [i32] = &mut [0, 1, 2, 3, 4];
+ let c2 = v2.array_chunks_mut::<2>();
+ assert_eq!(c2.last().unwrap(), &[2, 3]);
+}
+
+#[test]
+fn test_array_chunks_mut_remainder() {
+ let v: &mut [i32] = &mut [0, 1, 2, 3, 4];
+ let c = v.array_chunks_mut::<2>();
+ assert_eq!(c.into_remainder(), &[4]);
+}
+
+#[test]
+fn test_array_chunks_mut_zip() {
+ let v1: &mut [i32] = &mut [0, 1, 2, 3, 4];
+ let v2: &[i32] = &[6, 7, 8, 9, 10];
+
+ for (a, b) in v1.array_chunks_mut::<2>().zip(v2.array_chunks::<2>()) {
+ let sum = b.iter().sum::<i32>();
+ for v in a {
+ *v += sum;
+ }
+ }
+ assert_eq!(v1, [13, 14, 19, 20, 4]);
+}
+
+#[test]
+fn test_array_windows_infer() {
+ let v: &[i32] = &[0, 1, 0, 1];
+ assert_eq!(v.array_windows::<2>().count(), 3);
+ let c = v.array_windows();
+ for &[a, b] in c {
+ assert_eq!(a + b, 1);
+ }
+
+ let v2: &[i32] = &[0, 1, 2, 3, 4, 5, 6];
+ let total = v2.array_windows().map(|&[a, b, c]| a + b + c).sum::<i32>();
+ assert_eq!(total, 3 + 6 + 9 + 12 + 15);
+}
+
+#[test]
+fn test_array_windows_count() {
+ let v: &[i32] = &[0, 1, 2, 3, 4, 5];
+ let c = v.array_windows::<3>();
+ assert_eq!(c.count(), 4);
+
+ let v2: &[i32] = &[0, 1, 2, 3, 4];
+ let c2 = v2.array_windows::<6>();
+ assert_eq!(c2.count(), 0);
+
+ let v3: &[i32] = &[];
+ let c3 = v3.array_windows::<2>();
+ assert_eq!(c3.count(), 0);
+
+ let v4: &[()] = &[(); usize::MAX];
+ let c4 = v4.array_windows::<1>();
+ assert_eq!(c4.count(), usize::MAX);
+}
+
+#[test]
+fn test_array_windows_nth() {
+ let v: &[i32] = &[0, 1, 2, 3, 4, 5];
+ let snd = v.array_windows::<4>().nth(1);
+ assert_eq!(snd, Some(&[1, 2, 3, 4]));
+ let mut arr_windows = v.array_windows::<2>();
+ assert_ne!(arr_windows.nth(0), arr_windows.nth(0));
+ let last = v.array_windows::<3>().last();
+ assert_eq!(last, Some(&[3, 4, 5]));
+}
+
+#[test]
+fn test_array_windows_nth_back() {
+ let v: &[i32] = &[0, 1, 2, 3, 4, 5];
+ let snd = v.array_windows::<4>().nth_back(1);
+ assert_eq!(snd, Some(&[1, 2, 3, 4]));
+ let mut arr_windows = v.array_windows::<2>();
+ assert_ne!(arr_windows.nth_back(0), arr_windows.nth_back(0));
+}
+
+#[test]
+fn test_rchunks_count() {
+ let v: &[i32] = &[0, 1, 2, 3, 4, 5];
+ let c = v.rchunks(3);
+ assert_eq!(c.count(), 2);
+
+ let v2: &[i32] = &[0, 1, 2, 3, 4];
+ let c2 = v2.rchunks(2);
+ assert_eq!(c2.count(), 3);
+
+ let v3: &[i32] = &[];
+ let c3 = v3.rchunks(2);
+ assert_eq!(c3.count(), 0);
+}
+
+#[test]
+fn test_rchunks_nth() {
+ let v: &[i32] = &[0, 1, 2, 3, 4, 5];
+ let mut c = v.rchunks(2);
+ assert_eq!(c.nth(1).unwrap(), &[2, 3]);
+ assert_eq!(c.next().unwrap(), &[0, 1]);
+
+ let v2: &[i32] = &[0, 1, 2, 3, 4];
+ let mut c2 = v2.rchunks(3);
+ assert_eq!(c2.nth(1).unwrap(), &[0, 1]);
+ assert_eq!(c2.next(), None);
+}
+
+#[test]
+fn test_rchunks_nth_back() {
+ let v: &[i32] = &[0, 1, 2, 3, 4, 5];
+ let mut c = v.rchunks(2);
+ assert_eq!(c.nth_back(1).unwrap(), &[2, 3]);
+ assert_eq!(c.next_back().unwrap(), &[4, 5]);
+
+ let v2: &[i32] = &[0, 1, 2, 3, 4];
+ let mut c2 = v2.rchunks(3);
+ assert_eq!(c2.nth_back(1).unwrap(), &[2, 3, 4]);
+ assert_eq!(c2.next_back(), None);
+}
+
+#[test]
+fn test_rchunks_next() {
+ let v = [0, 1, 2, 3, 4, 5];
+ let mut c = v.rchunks(2);
+ assert_eq!(c.next().unwrap(), &[4, 5]);
+ assert_eq!(c.next().unwrap(), &[2, 3]);
+ assert_eq!(c.next().unwrap(), &[0, 1]);
+ assert_eq!(c.next(), None);
+
+ let v = [0, 1, 2, 3, 4, 5, 6, 7];
+ let mut c = v.rchunks(3);
+ assert_eq!(c.next().unwrap(), &[5, 6, 7]);
+ assert_eq!(c.next().unwrap(), &[2, 3, 4]);
+ assert_eq!(c.next().unwrap(), &[0, 1]);
+ assert_eq!(c.next(), None);
+}
+
+#[test]
+fn test_rchunks_next_back() {
+ let v = [0, 1, 2, 3, 4, 5];
+ let mut c = v.rchunks(2);
+ assert_eq!(c.next_back().unwrap(), &[0, 1]);
+ assert_eq!(c.next_back().unwrap(), &[2, 3]);
+ assert_eq!(c.next_back().unwrap(), &[4, 5]);
+ assert_eq!(c.next_back(), None);
+
+ let v = [0, 1, 2, 3, 4, 5, 6, 7];
+ let mut c = v.rchunks(3);
+ assert_eq!(c.next_back().unwrap(), &[0, 1]);
+ assert_eq!(c.next_back().unwrap(), &[2, 3, 4]);
+ assert_eq!(c.next_back().unwrap(), &[5, 6, 7]);
+ assert_eq!(c.next_back(), None);
+}
+
+#[test]
+fn test_rchunks_last() {
+ let v: &[i32] = &[0, 1, 2, 3, 4, 5];
+ let c = v.rchunks(2);
+ assert_eq!(c.last().unwrap()[1], 1);
+
+ let v2: &[i32] = &[0, 1, 2, 3, 4];
+ let c2 = v2.rchunks(2);
+ assert_eq!(c2.last().unwrap()[0], 0);
+}
+
+#[test]
+fn test_rchunks_zip() {
+ let v1: &[i32] = &[0, 1, 2, 3, 4];
+ let v2: &[i32] = &[6, 7, 8, 9, 10];
+
+ let res = v1
+ .rchunks(2)
+ .zip(v2.rchunks(2))
+ .map(|(a, b)| a.iter().sum::<i32>() + b.iter().sum::<i32>())
+ .collect::<Vec<_>>();
+ assert_eq!(res, vec![26, 18, 6]);
+}
+
+#[test]
+fn test_rchunks_mut_count() {
+ let v: &mut [i32] = &mut [0, 1, 2, 3, 4, 5];
+ let c = v.rchunks_mut(3);
+ assert_eq!(c.count(), 2);
+
+ let v2: &mut [i32] = &mut [0, 1, 2, 3, 4];
+ let c2 = v2.rchunks_mut(2);
+ assert_eq!(c2.count(), 3);
+
+ let v3: &mut [i32] = &mut [];
+ let c3 = v3.rchunks_mut(2);
+ assert_eq!(c3.count(), 0);
+}
+
+#[test]
+fn test_rchunks_mut_nth() {
+ let v: &mut [i32] = &mut [0, 1, 2, 3, 4, 5];
+ let mut c = v.rchunks_mut(2);
+ assert_eq!(c.nth(1).unwrap(), &[2, 3]);
+ assert_eq!(c.next().unwrap(), &[0, 1]);
+
+ let v2: &mut [i32] = &mut [0, 1, 2, 3, 4];
+ let mut c2 = v2.rchunks_mut(3);
+ assert_eq!(c2.nth(1).unwrap(), &[0, 1]);
+ assert_eq!(c2.next(), None);
+}
+
+#[test]
+fn test_rchunks_mut_nth_back() {
+ let v: &mut [i32] = &mut [0, 1, 2, 3, 4, 5];
+ let mut c = v.rchunks_mut(2);
+ assert_eq!(c.nth_back(1).unwrap(), &[2, 3]);
+ assert_eq!(c.next_back().unwrap(), &[4, 5]);
+
+ let v2: &mut [i32] = &mut [0, 1, 2, 3, 4];
+ let mut c2 = v2.rchunks_mut(3);
+ assert_eq!(c2.nth_back(1).unwrap(), &[2, 3, 4]);
+ assert_eq!(c2.next_back(), None);
+}
+
+#[test]
+fn test_rchunks_mut_next() {
+ let mut v = [0, 1, 2, 3, 4, 5];
+ let mut c = v.rchunks_mut(2);
+ assert_eq!(c.next().unwrap(), &mut [4, 5]);
+ assert_eq!(c.next().unwrap(), &mut [2, 3]);
+ assert_eq!(c.next().unwrap(), &mut [0, 1]);
+ assert_eq!(c.next(), None);
+
+ let mut v = [0, 1, 2, 3, 4, 5, 6, 7];
+ let mut c = v.rchunks_mut(3);
+ assert_eq!(c.next().unwrap(), &mut [5, 6, 7]);
+ assert_eq!(c.next().unwrap(), &mut [2, 3, 4]);
+ assert_eq!(c.next().unwrap(), &mut [0, 1]);
+ assert_eq!(c.next(), None);
+}
+
+#[test]
+fn test_rchunks_mut_next_back() {
+ let mut v = [0, 1, 2, 3, 4, 5];
+ let mut c = v.rchunks_mut(2);
+ assert_eq!(c.next_back().unwrap(), &mut [0, 1]);
+ assert_eq!(c.next_back().unwrap(), &mut [2, 3]);
+ assert_eq!(c.next_back().unwrap(), &mut [4, 5]);
+ assert_eq!(c.next_back(), None);
+
+ let mut v = [0, 1, 2, 3, 4, 5, 6, 7];
+ let mut c = v.rchunks_mut(3);
+ assert_eq!(c.next_back().unwrap(), &mut [0, 1]);
+ assert_eq!(c.next_back().unwrap(), &mut [2, 3, 4]);
+ assert_eq!(c.next_back().unwrap(), &mut [5, 6, 7]);
+ assert_eq!(c.next_back(), None);
+}
+
+#[test]
+fn test_rchunks_mut_last() {
+ let v: &mut [i32] = &mut [0, 1, 2, 3, 4, 5];
+ let c = v.rchunks_mut(2);
+ assert_eq!(c.last().unwrap(), &[0, 1]);
+
+ let v2: &mut [i32] = &mut [0, 1, 2, 3, 4];
+ let c2 = v2.rchunks_mut(2);
+ assert_eq!(c2.last().unwrap(), &[0]);
+}
+
+#[test]
+fn test_rchunks_mut_zip() {
+ let v1: &mut [i32] = &mut [0, 1, 2, 3, 4];
+ let v2: &[i32] = &[6, 7, 8, 9, 10];
+
+ for (a, b) in v1.rchunks_mut(2).zip(v2.rchunks(2)) {
+ let sum = b.iter().sum::<i32>();
+ for v in a {
+ *v += sum;
+ }
+ }
+ assert_eq!(v1, [6, 16, 17, 22, 23]);
+}
+
+#[test]
+fn test_rchunks_exact_count() {
+ let v: &[i32] = &[0, 1, 2, 3, 4, 5];
+ let c = v.rchunks_exact(3);
+ assert_eq!(c.count(), 2);
+
+ let v2: &[i32] = &[0, 1, 2, 3, 4];
+ let c2 = v2.rchunks_exact(2);
+ assert_eq!(c2.count(), 2);
+
+ let v3: &[i32] = &[];
+ let c3 = v3.rchunks_exact(2);
+ assert_eq!(c3.count(), 0);
+}
+
+#[test]
+fn test_rchunks_exact_nth() {
+ let v: &[i32] = &[0, 1, 2, 3, 4, 5];
+ let mut c = v.rchunks_exact(2);
+ assert_eq!(c.nth(1).unwrap(), &[2, 3]);
+ assert_eq!(c.next().unwrap(), &[0, 1]);
+
+ let v2: &[i32] = &[0, 1, 2, 3, 4, 5, 6];
+ let mut c2 = v2.rchunks_exact(3);
+ assert_eq!(c2.nth(1).unwrap(), &[1, 2, 3]);
+ assert_eq!(c2.next(), None);
+}
+
+#[test]
+fn test_rchunks_exact_nth_back() {
+ let v: &[i32] = &[0, 1, 2, 3, 4, 5];
+ let mut c = v.rchunks_exact(2);
+ assert_eq!(c.nth_back(1).unwrap(), &[2, 3]);
+ assert_eq!(c.next_back().unwrap(), &[4, 5]);
+
+ let v2: &[i32] = &[0, 1, 2, 3, 4, 5, 6];
+ let mut c2 = v2.rchunks_exact(3);
+ assert_eq!(c2.nth_back(1).unwrap(), &[4, 5, 6]);
+ assert_eq!(c2.next(), None);
+}
+
+#[test]
+fn test_rchunks_exact_last() {
+ let v: &[i32] = &[0, 1, 2, 3, 4, 5];
+ let c = v.rchunks_exact(2);
+ assert_eq!(c.last().unwrap(), &[0, 1]);
+
+ let v2: &[i32] = &[0, 1, 2, 3, 4];
+ let c2 = v2.rchunks_exact(2);
+ assert_eq!(c2.last().unwrap(), &[1, 2]);
+}
+
+#[test]
+fn test_rchunks_exact_remainder() {
+ let v: &[i32] = &[0, 1, 2, 3, 4];
+ let c = v.rchunks_exact(2);
+ assert_eq!(c.remainder(), &[0]);
+}
+
+#[test]
+fn test_rchunks_exact_zip() {
+ let v1: &[i32] = &[0, 1, 2, 3, 4];
+ let v2: &[i32] = &[6, 7, 8, 9, 10];
+
+ let res = v1
+ .rchunks_exact(2)
+ .zip(v2.rchunks_exact(2))
+ .map(|(a, b)| a.iter().sum::<i32>() + b.iter().sum::<i32>())
+ .collect::<Vec<_>>();
+ assert_eq!(res, vec![26, 18]);
+}
+
+#[test]
+fn test_rchunks_exact_mut_count() {
+ let v: &mut [i32] = &mut [0, 1, 2, 3, 4, 5];
+ let c = v.rchunks_exact_mut(3);
+ assert_eq!(c.count(), 2);
+
+ let v2: &mut [i32] = &mut [0, 1, 2, 3, 4];
+ let c2 = v2.rchunks_exact_mut(2);
+ assert_eq!(c2.count(), 2);
+
+ let v3: &mut [i32] = &mut [];
+ let c3 = v3.rchunks_exact_mut(2);
+ assert_eq!(c3.count(), 0);
+}
+
+#[test]
+fn test_rchunks_exact_mut_nth() {
+ let v: &mut [i32] = &mut [0, 1, 2, 3, 4, 5];
+ let mut c = v.rchunks_exact_mut(2);
+ assert_eq!(c.nth(1).unwrap(), &[2, 3]);
+ assert_eq!(c.next().unwrap(), &[0, 1]);
+
+ let v2: &mut [i32] = &mut [0, 1, 2, 3, 4, 5, 6];
+ let mut c2 = v2.rchunks_exact_mut(3);
+ assert_eq!(c2.nth(1).unwrap(), &[1, 2, 3]);
+ assert_eq!(c2.next(), None);
+}
+
+#[test]
+fn test_rchunks_exact_mut_nth_back() {
+ let v: &mut [i32] = &mut [0, 1, 2, 3, 4, 5];
+ let mut c = v.rchunks_exact_mut(2);
+ assert_eq!(c.nth_back(1).unwrap(), &[2, 3]);
+ assert_eq!(c.next_back().unwrap(), &[4, 5]);
+
+ let v2: &mut [i32] = &mut [0, 1, 2, 3, 4, 5, 6];
+ let mut c2 = v2.rchunks_exact_mut(3);
+ assert_eq!(c2.nth_back(1).unwrap(), &[4, 5, 6]);
+ assert_eq!(c2.next(), None);
+}
+
+#[test]
+fn test_rchunks_exact_mut_last() {
+ let v: &mut [i32] = &mut [0, 1, 2, 3, 4, 5];
+ let c = v.rchunks_exact_mut(2);
+ assert_eq!(c.last().unwrap(), &[0, 1]);
+
+ let v2: &mut [i32] = &mut [0, 1, 2, 3, 4];
+ let c2 = v2.rchunks_exact_mut(2);
+ assert_eq!(c2.last().unwrap(), &[1, 2]);
+}
+
+#[test]
+fn test_rchunks_exact_mut_remainder() {
+ let v: &mut [i32] = &mut [0, 1, 2, 3, 4];
+ let c = v.rchunks_exact_mut(2);
+ assert_eq!(c.into_remainder(), &[0]);
+}
+
+#[test]
+fn test_rchunks_exact_mut_zip() {
+ let v1: &mut [i32] = &mut [0, 1, 2, 3, 4];
+ let v2: &[i32] = &[6, 7, 8, 9, 10];
+
+ for (a, b) in v1.rchunks_exact_mut(2).zip(v2.rchunks_exact(2)) {
+ let sum = b.iter().sum::<i32>();
+ for v in a {
+ *v += sum;
+ }
+ }
+ assert_eq!(v1, [0, 16, 17, 22, 23]);
+}
+
+#[test]
+fn chunks_mut_are_send_and_sync() {
+ use std::cell::Cell;
+ use std::slice::{ChunksExactMut, ChunksMut, RChunksExactMut, RChunksMut};
+ use std::sync::MutexGuard;
+
+ #[allow(unused)]
+ fn assert_send_and_sync()
+ where
+ ChunksMut<'static, Cell<i32>>: Send,
+ ChunksMut<'static, MutexGuard<'static, u32>>: Sync,
+ ChunksExactMut<'static, Cell<i32>>: Send,
+ ChunksExactMut<'static, MutexGuard<'static, u32>>: Sync,
+ RChunksMut<'static, Cell<i32>>: Send,
+ RChunksMut<'static, MutexGuard<'static, u32>>: Sync,
+ RChunksExactMut<'static, Cell<i32>>: Send,
+ RChunksExactMut<'static, MutexGuard<'static, u32>>: Sync,
+ {
+ }
+}
+
+#[test]
+fn test_windows_count() {
+ let v: &[i32] = &[0, 1, 2, 3, 4, 5];
+ let c = v.windows(3);
+ assert_eq!(c.count(), 4);
+
+ let v2: &[i32] = &[0, 1, 2, 3, 4];
+ let c2 = v2.windows(6);
+ assert_eq!(c2.count(), 0);
+
+ let v3: &[i32] = &[];
+ let c3 = v3.windows(2);
+ assert_eq!(c3.count(), 0);
+
+ let v4 = &[(); usize::MAX];
+ let c4 = v4.windows(1);
+ assert_eq!(c4.count(), usize::MAX);
+}
+
+#[test]
+fn test_windows_nth() {
+ let v: &[i32] = &[0, 1, 2, 3, 4, 5];
+ let mut c = v.windows(2);
+ assert_eq!(c.nth(2).unwrap()[1], 3);
+ assert_eq!(c.next().unwrap()[0], 3);
+
+ let v2: &[i32] = &[0, 1, 2, 3, 4];
+ let mut c2 = v2.windows(4);
+ assert_eq!(c2.nth(1).unwrap()[1], 2);
+ assert_eq!(c2.next(), None);
+}
+
+#[test]
+fn test_windows_nth_back() {
+ let v: &[i32] = &[0, 1, 2, 3, 4, 5];
+ let mut c = v.windows(2);
+ assert_eq!(c.nth_back(2).unwrap()[0], 2);
+ assert_eq!(c.next_back().unwrap()[1], 2);
+
+ let v2: &[i32] = &[0, 1, 2, 3, 4];
+ let mut c2 = v2.windows(4);
+ assert_eq!(c2.nth_back(1).unwrap()[1], 1);
+ assert_eq!(c2.next_back(), None);
+}
+
+#[test]
+fn test_windows_last() {
+ let v: &[i32] = &[0, 1, 2, 3, 4, 5];
+ let c = v.windows(2);
+ assert_eq!(c.last().unwrap()[1], 5);
+
+ let v2: &[i32] = &[0, 1, 2, 3, 4];
+ let c2 = v2.windows(2);
+ assert_eq!(c2.last().unwrap()[0], 3);
+}
+
+#[test]
+fn test_windows_zip() {
+ let v1: &[i32] = &[0, 1, 2, 3, 4];
+ let v2: &[i32] = &[6, 7, 8, 9, 10];
+
+ let res = v1
+ .windows(2)
+ .zip(v2.windows(2))
+ .map(|(a, b)| a.iter().sum::<i32>() + b.iter().sum::<i32>())
+ .collect::<Vec<_>>();
+
+ assert_eq!(res, [14, 18, 22, 26]);
+}
+
+#[test]
+#[allow(const_err)]
+fn test_iter_ref_consistency() {
+ use std::fmt::Debug;
+
+ fn test<T: Copy + Debug + PartialEq>(x: T) {
+ let v: &[T] = &[x, x, x];
+ let v_ptrs: [*const T; 3] = match v {
+ [ref v1, ref v2, ref v3] => [v1 as *const _, v2 as *const _, v3 as *const _],
+ _ => unreachable!(),
+ };
+ let len = v.len();
+
+ // nth(i)
+ for i in 0..len {
+ assert_eq!(&v[i] as *const _, v_ptrs[i]); // check the v_ptrs array, just to be sure
+ let nth = v.iter().nth(i).unwrap();
+ assert_eq!(nth as *const _, v_ptrs[i]);
+ }
+ assert_eq!(v.iter().nth(len), None, "nth(len) should return None");
+
+ // stepping through with nth(0)
+ {
+ let mut it = v.iter();
+ for i in 0..len {
+ let next = it.nth(0).unwrap();
+ assert_eq!(next as *const _, v_ptrs[i]);
+ }
+ assert_eq!(it.nth(0), None);
+ }
+
+ // next()
+ {
+ let mut it = v.iter();
+ for i in 0..len {
+ let remaining = len - i;
+ assert_eq!(it.size_hint(), (remaining, Some(remaining)));
+
+ let next = it.next().unwrap();
+ assert_eq!(next as *const _, v_ptrs[i]);
+ }
+ assert_eq!(it.size_hint(), (0, Some(0)));
+ assert_eq!(it.next(), None, "The final call to next() should return None");
+ }
+
+ // next_back()
+ {
+ let mut it = v.iter();
+ for i in 0..len {
+ let remaining = len - i;
+ assert_eq!(it.size_hint(), (remaining, Some(remaining)));
+
+ let prev = it.next_back().unwrap();
+ assert_eq!(prev as *const _, v_ptrs[remaining - 1]);
+ }
+ assert_eq!(it.size_hint(), (0, Some(0)));
+ assert_eq!(it.next_back(), None, "The final call to next_back() should return None");
+ }
+ }
+
+ fn test_mut<T: Copy + Debug + PartialEq>(x: T) {
+ let v: &mut [T] = &mut [x, x, x];
+ let v_ptrs: [*mut T; 3] = match v {
+ [ref v1, ref v2, ref v3] => {
+ [v1 as *const _ as *mut _, v2 as *const _ as *mut _, v3 as *const _ as *mut _]
+ }
+ _ => unreachable!(),
+ };
+ let len = v.len();
+
+ // nth(i)
+ for i in 0..len {
+ assert_eq!(&mut v[i] as *mut _, v_ptrs[i]); // check the v_ptrs array, just to be sure
+ let nth = v.iter_mut().nth(i).unwrap();
+ assert_eq!(nth as *mut _, v_ptrs[i]);
+ }
+ assert_eq!(v.iter().nth(len), None, "nth(len) should return None");
+
+ // stepping through with nth(0)
+ {
+ let mut it = v.iter();
+ for i in 0..len {
+ let next = it.nth(0).unwrap();
+ assert_eq!(next as *const _, v_ptrs[i]);
+ }
+ assert_eq!(it.nth(0), None);
+ }
+
+ // next()
+ {
+ let mut it = v.iter_mut();
+ for i in 0..len {
+ let remaining = len - i;
+ assert_eq!(it.size_hint(), (remaining, Some(remaining)));
+
+ let next = it.next().unwrap();
+ assert_eq!(next as *mut _, v_ptrs[i]);
+ }
+ assert_eq!(it.size_hint(), (0, Some(0)));
+ assert_eq!(it.next(), None, "The final call to next() should return None");
+ }
+
+ // next_back()
+ {
+ let mut it = v.iter_mut();
+ for i in 0..len {
+ let remaining = len - i;
+ assert_eq!(it.size_hint(), (remaining, Some(remaining)));
+
+ let prev = it.next_back().unwrap();
+ assert_eq!(prev as *mut _, v_ptrs[remaining - 1]);
+ }
+ assert_eq!(it.size_hint(), (0, Some(0)));
+ assert_eq!(it.next_back(), None, "The final call to next_back() should return None");
+ }
+ }
+
+ // Make sure iterators and slice patterns yield consistent addresses for various types,
+ // including ZSTs.
+ test(0u32);
+ test(());
+ test([0u32; 0]); // ZST with alignment > 0
+ test_mut(0u32);
+ test_mut(());
+ test_mut([0u32; 0]); // ZST with alignment > 0
+}
+
+// The current implementation of SliceIndex fails to handle methods
+// orthogonally from range types; therefore, it is worth testing
+// all of the indexing operations on each input.
+mod slice_index {
+ // This checks all six indexing methods, given an input range that
+ // should succeed. (it is NOT suitable for testing invalid inputs)
+ macro_rules! assert_range_eq {
+ ($arr:expr, $range:expr, $expected:expr) => {
+ let mut arr = $arr;
+ let mut expected = $expected;
+ {
+ let s: &[_] = &arr;
+ let expected: &[_] = &expected;
+
+ assert_eq!(&s[$range], expected, "(in assertion for: index)");
+ assert_eq!(s.get($range), Some(expected), "(in assertion for: get)");
+ unsafe {
+ assert_eq!(
+ s.get_unchecked($range),
+ expected,
+ "(in assertion for: get_unchecked)",
+ );
+ }
+ }
+ {
+ let s: &mut [_] = &mut arr;
+ let expected: &mut [_] = &mut expected;
+
+ assert_eq!(&mut s[$range], expected, "(in assertion for: index_mut)",);
+ assert_eq!(
+ s.get_mut($range),
+ Some(&mut expected[..]),
+ "(in assertion for: get_mut)",
+ );
+ unsafe {
+ assert_eq!(
+ s.get_unchecked_mut($range),
+ expected,
+ "(in assertion for: get_unchecked_mut)",
+ );
+ }
+ }
+ };
+ }
+
+ // Make sure the macro can actually detect bugs,
+ // because if it can't, then what are we even doing here?
+ //
+ // (Be aware this only demonstrates the ability to detect bugs
+ // in the FIRST method that panics, as the macro is not designed
+ // to be used in `should_panic`)
+ #[test]
+ #[should_panic(expected = "out of range")]
+ fn assert_range_eq_can_fail_by_panic() {
+ assert_range_eq!([0, 1, 2], 0..5, [0, 1, 2]);
+ }
+
+ // (Be aware this only demonstrates the ability to detect bugs
+ // in the FIRST method it calls, as the macro is not designed
+ // to be used in `should_panic`)
+ #[test]
+ #[should_panic(expected = "==")]
+ fn assert_range_eq_can_fail_by_inequality() {
+ assert_range_eq!([0, 1, 2], 0..2, [0, 1, 2]);
+ }
+
+ // Test cases for bad index operations.
+ //
+ // This generates `should_panic` test cases for Index/IndexMut
+ // and `None` test cases for get/get_mut.
+ macro_rules! panic_cases {
+ ($(
+ // each test case needs a unique name to namespace the tests
+ in mod $case_name:ident {
+ data: $data:expr;
+
+ // optional:
+ //
+ // one or more similar inputs for which data[input] succeeds,
+ // and the corresponding output as an array. This helps validate
+ // "critical points" where an input range straddles the boundary
+ // between valid and invalid.
+ // (such as the input `len..len`, which is just barely valid)
+ $(
+ good: data[$good:expr] == $output:expr;
+ )*
+
+ bad: data[$bad:expr];
+ message: $expect_msg:expr;
+ }
+ )*) => {$(
+ mod $case_name {
+ #[allow(unused_imports)]
+ use core::ops::Bound;
+
+ #[test]
+ fn pass() {
+ let mut v = $data;
+
+ $( assert_range_eq!($data, $good, $output); )*
+
+ {
+ let v: &[_] = &v;
+ assert_eq!(v.get($bad), None, "(in None assertion for get)");
+ }
+
+ {
+ let v: &mut [_] = &mut v;
+ assert_eq!(v.get_mut($bad), None, "(in None assertion for get_mut)");
+ }
+ }
+
+ #[test]
+ #[should_panic(expected = $expect_msg)]
+ fn index_fail() {
+ let v = $data;
+ let v: &[_] = &v;
+ let _v = &v[$bad];
+ }
+
+ #[test]
+ #[should_panic(expected = $expect_msg)]
+ fn index_mut_fail() {
+ let mut v = $data;
+ let v: &mut [_] = &mut v;
+ let _v = &mut v[$bad];
+ }
+ }
+ )*};
+ }
+
+ #[test]
+ fn simple() {
+ let v = [0, 1, 2, 3, 4, 5];
+
+ assert_range_eq!(v, .., [0, 1, 2, 3, 4, 5]);
+ assert_range_eq!(v, ..2, [0, 1]);
+ assert_range_eq!(v, ..=1, [0, 1]);
+ assert_range_eq!(v, 2.., [2, 3, 4, 5]);
+ assert_range_eq!(v, 1..4, [1, 2, 3]);
+ assert_range_eq!(v, 1..=3, [1, 2, 3]);
+ }
+
+ panic_cases! {
+ in mod rangefrom_len {
+ data: [0, 1, 2, 3, 4, 5];
+
+ good: data[6..] == [];
+ bad: data[7..];
+ message: "out of range";
+ }
+
+ in mod rangeto_len {
+ data: [0, 1, 2, 3, 4, 5];
+
+ good: data[..6] == [0, 1, 2, 3, 4, 5];
+ bad: data[..7];
+ message: "out of range";
+ }
+
+ in mod rangetoinclusive_len {
+ data: [0, 1, 2, 3, 4, 5];
+
+ good: data[..=5] == [0, 1, 2, 3, 4, 5];
+ bad: data[..=6];
+ message: "out of range";
+ }
+
+ in mod rangeinclusive_len {
+ data: [0, 1, 2, 3, 4, 5];
+
+ good: data[0..=5] == [0, 1, 2, 3, 4, 5];
+ bad: data[0..=6];
+ message: "out of range";
+ }
+
+ in mod range_len_len {
+ data: [0, 1, 2, 3, 4, 5];
+
+ good: data[6..6] == [];
+ bad: data[7..7];
+ message: "out of range";
+ }
+
+ in mod rangeinclusive_len_len {
+ data: [0, 1, 2, 3, 4, 5];
+
+ good: data[6..=5] == [];
+ bad: data[7..=6];
+ message: "out of range";
+ }
+
+ in mod boundpair_len {
+ data: [0, 1, 2, 3, 4, 5];
+
+ good: data[(Bound::Included(6), Bound::Unbounded)] == [];
+ good: data[(Bound::Unbounded, Bound::Included(5))] == [0, 1, 2, 3, 4, 5];
+ good: data[(Bound::Unbounded, Bound::Excluded(6))] == [0, 1, 2, 3, 4, 5];
+ good: data[(Bound::Included(0), Bound::Included(5))] == [0, 1, 2, 3, 4, 5];
+ good: data[(Bound::Included(0), Bound::Excluded(6))] == [0, 1, 2, 3, 4, 5];
+ good: data[(Bound::Included(2), Bound::Excluded(4))] == [2, 3];
+ good: data[(Bound::Excluded(1), Bound::Included(4))] == [2, 3, 4];
+ good: data[(Bound::Excluded(5), Bound::Excluded(6))] == [];
+ good: data[(Bound::Included(6), Bound::Excluded(6))] == [];
+ good: data[(Bound::Excluded(5), Bound::Included(5))] == [];
+ good: data[(Bound::Included(6), Bound::Included(5))] == [];
+ bad: data[(Bound::Unbounded, Bound::Included(6))];
+ message: "out of range";
+ }
+ }
+
+ panic_cases! {
+ in mod rangeinclusive_exhausted {
+ data: [0, 1, 2, 3, 4, 5];
+
+ good: data[0..=5] == [0, 1, 2, 3, 4, 5];
+ good: data[{
+ let mut iter = 0..=5;
+ iter.by_ref().count(); // exhaust it
+ iter
+ }] == [];
+
+ // 0..=6 is out of range before exhaustion, so it
+ // stands to reason that it still would be after.
+ bad: data[{
+ let mut iter = 0..=6;
+ iter.by_ref().count(); // exhaust it
+ iter
+ }];
+ message: "out of range";
+ }
+ }
+
+ panic_cases! {
+ in mod range_neg_width {
+ data: [0, 1, 2, 3, 4, 5];
+
+ good: data[4..4] == [];
+ bad: data[4..3];
+ message: "but ends at";
+ }
+
+ in mod rangeinclusive_neg_width {
+ data: [0, 1, 2, 3, 4, 5];
+
+ good: data[4..=3] == [];
+ bad: data[4..=2];
+ message: "but ends at";
+ }
+
+ in mod boundpair_neg_width {
+ data: [0, 1, 2, 3, 4, 5];
+
+ good: data[(Bound::Included(4), Bound::Excluded(4))] == [];
+ bad: data[(Bound::Included(4), Bound::Excluded(3))];
+ message: "but ends at";
+ }
+ }
+
+ panic_cases! {
+ in mod rangeinclusive_overflow {
+ data: [0, 1];
+
+ // note: using 0 specifically ensures that the result of overflowing is 0..0,
+ // so that `get` doesn't simply return None for the wrong reason.
+ bad: data[0 ..= usize::MAX];
+ message: "maximum usize";
+ }
+
+ in mod rangetoinclusive_overflow {
+ data: [0, 1];
+
+ bad: data[..= usize::MAX];
+ message: "maximum usize";
+ }
+
+ in mod boundpair_overflow_end {
+ data: [0; 1];
+
+ bad: data[(Bound::Unbounded, Bound::Included(usize::MAX))];
+ message: "maximum usize";
+ }
+
+ in mod boundpair_overflow_start {
+ data: [0; 1];
+
+ bad: data[(Bound::Excluded(usize::MAX), Bound::Unbounded)];
+ message: "maximum usize";
+ }
+ } // panic_cases!
+}
+
+#[test]
+fn test_find_rfind() {
+ let v = [0, 1, 2, 3, 4, 5];
+ let mut iter = v.iter();
+ let mut i = v.len();
+ while let Some(&elt) = iter.rfind(|_| true) {
+ i -= 1;
+ assert_eq!(elt, v[i]);
+ }
+ assert_eq!(i, 0);
+ assert_eq!(v.iter().rfind(|&&x| x <= 3), Some(&3));
+}
+
+#[test]
+fn test_iter_folds() {
+ let a = [1, 2, 3, 4, 5]; // len>4 so the unroll is used
+ assert_eq!(a.iter().fold(0, |acc, &x| 2 * acc + x), 57);
+ assert_eq!(a.iter().rfold(0, |acc, &x| 2 * acc + x), 129);
+ let fold = |acc: i32, &x| acc.checked_mul(2)?.checked_add(x);
+ assert_eq!(a.iter().try_fold(0, &fold), Some(57));
+ assert_eq!(a.iter().try_rfold(0, &fold), Some(129));
+
+ // short-circuiting try_fold, through other methods
+ let a = [0, 1, 2, 3, 5, 5, 5, 7, 8, 9];
+ let mut iter = a.iter();
+ assert_eq!(iter.position(|&x| x == 3), Some(3));
+ assert_eq!(iter.rfind(|&&x| x == 5), Some(&5));
+ assert_eq!(iter.len(), 2);
+}
+
+#[test]
+fn test_rotate_left() {
+ const N: usize = 600;
+ let a: &mut [_] = &mut [0; N];
+ for i in 0..N {
+ a[i] = i;
+ }
+
+ a.rotate_left(42);
+ let k = N - 42;
+
+ for i in 0..N {
+ assert_eq!(a[(i + k) % N], i);
+ }
+}
+
+#[test]
+fn test_rotate_right() {
+ const N: usize = 600;
+ let a: &mut [_] = &mut [0; N];
+ for i in 0..N {
+ a[i] = i;
+ }
+
+ a.rotate_right(42);
+
+ for i in 0..N {
+ assert_eq!(a[(i + 42) % N], i);
+ }
+}
+
+#[test]
+#[cfg_attr(miri, ignore)] // Miri is too slow
+fn brute_force_rotate_test_0() {
+ // In case of edge cases involving multiple algorithms
+ let n = 300;
+ for len in 0..n {
+ for s in 0..len {
+ let mut v = Vec::with_capacity(len);
+ for i in 0..len {
+ v.push(i);
+ }
+ v[..].rotate_right(s);
+ for i in 0..v.len() {
+ assert_eq!(v[i], v.len().wrapping_add(i.wrapping_sub(s)) % v.len());
+ }
+ }
+ }
+}
+
+#[test]
+fn brute_force_rotate_test_1() {
+ // `ptr_rotate` covers so many kinds of pointer usage, that this is just a good test for
+ // pointers in general. This uses a `[usize; 4]` to hit all algorithms without overwhelming miri
+ let n = 30;
+ for len in 0..n {
+ for s in 0..len {
+ let mut v: Vec<[usize; 4]> = Vec::with_capacity(len);
+ for i in 0..len {
+ v.push([i, 0, 0, 0]);
+ }
+ v[..].rotate_right(s);
+ for i in 0..v.len() {
+ assert_eq!(v[i][0], v.len().wrapping_add(i.wrapping_sub(s)) % v.len());
+ }
+ }
+ }
+}
+
+#[test]
+#[cfg(not(target_arch = "wasm32"))]
+fn sort_unstable() {
+ use core::cmp::Ordering::{Equal, Greater, Less};
+ use core::slice::heapsort;
+ use rand::{rngs::StdRng, seq::SliceRandom, Rng, SeedableRng};
+
+ // Miri is too slow (but still need to `chain` to make the types match)
+ let lens = if cfg!(miri) { (2..20).chain(0..0) } else { (2..25).chain(500..510) };
+ let rounds = if cfg!(miri) { 1 } else { 100 };
+
+ let mut v = [0; 600];
+ let mut tmp = [0; 600];
+ let mut rng = StdRng::from_entropy();
+
+ for len in lens {
+ let v = &mut v[0..len];
+ let tmp = &mut tmp[0..len];
+
+ for &modulus in &[5, 10, 100, 1000] {
+ for _ in 0..rounds {
+ for i in 0..len {
+ v[i] = rng.gen::<i32>() % modulus;
+ }
+
+ // Sort in default order.
+ tmp.copy_from_slice(v);
+ tmp.sort_unstable();
+ assert!(tmp.windows(2).all(|w| w[0] <= w[1]));
+
+ // Sort in ascending order.
+ tmp.copy_from_slice(v);
+ tmp.sort_unstable_by(|a, b| a.cmp(b));
+ assert!(tmp.windows(2).all(|w| w[0] <= w[1]));
+
+ // Sort in descending order.
+ tmp.copy_from_slice(v);
+ tmp.sort_unstable_by(|a, b| b.cmp(a));
+ assert!(tmp.windows(2).all(|w| w[0] >= w[1]));
+
+ // Test heapsort using `<` operator.
+ tmp.copy_from_slice(v);
+ heapsort(tmp, |a, b| a < b);
+ assert!(tmp.windows(2).all(|w| w[0] <= w[1]));
+
+ // Test heapsort using `>` operator.
+ tmp.copy_from_slice(v);
+ heapsort(tmp, |a, b| a > b);
+ assert!(tmp.windows(2).all(|w| w[0] >= w[1]));
+ }
+ }
+ }
+
+ // Sort using a completely random comparison function.
+ // This will reorder the elements *somehow*, but won't panic.
+ for i in 0..v.len() {
+ v[i] = i as i32;
+ }
+ v.sort_unstable_by(|_, _| *[Less, Equal, Greater].choose(&mut rng).unwrap());
+ v.sort_unstable();
+ for i in 0..v.len() {
+ assert_eq!(v[i], i as i32);
+ }
+
+ // Should not panic.
+ [0i32; 0].sort_unstable();
+ [(); 10].sort_unstable();
+ [(); 100].sort_unstable();
+
+ let mut v = [0xDEADBEEFu64];
+ v.sort_unstable();
+ assert!(v == [0xDEADBEEF]);
+}
+
+#[test]
+#[cfg(not(target_arch = "wasm32"))]
+#[cfg_attr(miri, ignore)] // Miri is too slow
+fn select_nth_unstable() {
+ use core::cmp::Ordering::{Equal, Greater, Less};
+ use rand::rngs::StdRng;
+ use rand::seq::SliceRandom;
+ use rand::{Rng, SeedableRng};
+
+ let mut rng = StdRng::from_entropy();
+
+ for len in (2..21).chain(500..501) {
+ let mut orig = vec![0; len];
+
+ for &modulus in &[5, 10, 1000] {
+ for _ in 0..10 {
+ for i in 0..len {
+ orig[i] = rng.gen::<i32>() % modulus;
+ }
+
+ let v_sorted = {
+ let mut v = orig.clone();
+ v.sort();
+ v
+ };
+
+ // Sort in default order.
+ for pivot in 0..len {
+ let mut v = orig.clone();
+ v.select_nth_unstable(pivot);
+
+ assert_eq!(v_sorted[pivot], v[pivot]);
+ for i in 0..pivot {
+ for j in pivot..len {
+ assert!(v[i] <= v[j]);
+ }
+ }
+ }
+
+ // Sort in ascending order.
+ for pivot in 0..len {
+ let mut v = orig.clone();
+ let (left, pivot, right) = v.select_nth_unstable_by(pivot, |a, b| a.cmp(b));
+
+ assert_eq!(left.len() + right.len(), len - 1);
+
+ for l in left {
+ assert!(l <= pivot);
+ for r in right.iter_mut() {
+ assert!(l <= r);
+ assert!(pivot <= r);
+ }
+ }
+ }
+
+ // Sort in descending order.
+ let sort_descending_comparator = |a: &i32, b: &i32| b.cmp(a);
+ let v_sorted_descending = {
+ let mut v = orig.clone();
+ v.sort_by(sort_descending_comparator);
+ v
+ };
+
+ for pivot in 0..len {
+ let mut v = orig.clone();
+ v.select_nth_unstable_by(pivot, sort_descending_comparator);
+
+ assert_eq!(v_sorted_descending[pivot], v[pivot]);
+ for i in 0..pivot {
+ for j in pivot..len {
+ assert!(v[j] <= v[i]);
+ }
+ }
+ }
+ }
+ }
+ }
+
+ // Sort at index using a completely random comparison function.
+ // This will reorder the elements *somehow*, but won't panic.
+ let mut v = [0; 500];
+ for i in 0..v.len() {
+ v[i] = i as i32;
+ }
+
+ for pivot in 0..v.len() {
+ v.select_nth_unstable_by(pivot, |_, _| *[Less, Equal, Greater].choose(&mut rng).unwrap());
+ v.sort();
+ for i in 0..v.len() {
+ assert_eq!(v[i], i as i32);
+ }
+ }
+
+ // Should not panic.
+ [(); 10].select_nth_unstable(0);
+ [(); 10].select_nth_unstable(5);
+ [(); 10].select_nth_unstable(9);
+ [(); 100].select_nth_unstable(0);
+ [(); 100].select_nth_unstable(50);
+ [(); 100].select_nth_unstable(99);
+
+ let mut v = [0xDEADBEEFu64];
+ v.select_nth_unstable(0);
+ assert!(v == [0xDEADBEEF]);
+}
+
+#[test]
+#[should_panic(expected = "index 0 greater than length of slice")]
+fn select_nth_unstable_zero_length() {
+ [0i32; 0].select_nth_unstable(0);
+}
+
+#[test]
+#[should_panic(expected = "index 20 greater than length of slice")]
+fn select_nth_unstable_past_length() {
+ [0i32; 10].select_nth_unstable(20);
+}
+
+pub mod memchr {
+ use core::slice::memchr::{memchr, memrchr};
+
+ // test fallback implementations on all platforms
+ #[test]
+ fn matches_one() {
+ assert_eq!(Some(0), memchr(b'a', b"a"));
+ }
+
+ #[test]
+ fn matches_begin() {
+ assert_eq!(Some(0), memchr(b'a', b"aaaa"));
+ }
+
+ #[test]
+ fn matches_end() {
+ assert_eq!(Some(4), memchr(b'z', b"aaaaz"));
+ }
+
+ #[test]
+ fn matches_nul() {
+ assert_eq!(Some(4), memchr(b'\x00', b"aaaa\x00"));
+ }
+
+ #[test]
+ fn matches_past_nul() {
+ assert_eq!(Some(5), memchr(b'z', b"aaaa\x00z"));
+ }
+
+ #[test]
+ fn no_match_empty() {
+ assert_eq!(None, memchr(b'a', b""));
+ }
+
+ #[test]
+ fn no_match() {
+ assert_eq!(None, memchr(b'a', b"xyz"));
+ }
+
+ #[test]
+ fn matches_one_reversed() {
+ assert_eq!(Some(0), memrchr(b'a', b"a"));
+ }
+
+ #[test]
+ fn matches_begin_reversed() {
+ assert_eq!(Some(3), memrchr(b'a', b"aaaa"));
+ }
+
+ #[test]
+ fn matches_end_reversed() {
+ assert_eq!(Some(0), memrchr(b'z', b"zaaaa"));
+ }
+
+ #[test]
+ fn matches_nul_reversed() {
+ assert_eq!(Some(4), memrchr(b'\x00', b"aaaa\x00"));
+ }
+
+ #[test]
+ fn matches_past_nul_reversed() {
+ assert_eq!(Some(0), memrchr(b'z', b"z\x00aaaa"));
+ }
+
+ #[test]
+ fn no_match_empty_reversed() {
+ assert_eq!(None, memrchr(b'a', b""));
+ }
+
+ #[test]
+ fn no_match_reversed() {
+ assert_eq!(None, memrchr(b'a', b"xyz"));
+ }
+
+ #[test]
+ fn each_alignment_reversed() {
+ let mut data = [1u8; 64];
+ let needle = 2;
+ let pos = 40;
+ data[pos] = needle;
+ for start in 0..16 {
+ assert_eq!(Some(pos - start), memrchr(needle, &data[start..]));
+ }
+ }
+}
+
+#[test]
+fn test_align_to_simple() {
+ let bytes = [1u8, 2, 3, 4, 5, 6, 7];
+ let (prefix, aligned, suffix) = unsafe { bytes.align_to::<u16>() };
+ assert_eq!(aligned.len(), 3);
+ assert!(prefix == [1] || suffix == [7]);
+ let expect1 = [1 << 8 | 2, 3 << 8 | 4, 5 << 8 | 6];
+ let expect2 = [1 | 2 << 8, 3 | 4 << 8, 5 | 6 << 8];
+ let expect3 = [2 << 8 | 3, 4 << 8 | 5, 6 << 8 | 7];
+ let expect4 = [2 | 3 << 8, 4 | 5 << 8, 6 | 7 << 8];
+ assert!(
+ aligned == expect1 || aligned == expect2 || aligned == expect3 || aligned == expect4,
+ "aligned={:?} expected={:?} || {:?} || {:?} || {:?}",
+ aligned,
+ expect1,
+ expect2,
+ expect3,
+ expect4
+ );
+}
+
+#[test]
+fn test_align_to_zst() {
+ let bytes = [1, 2, 3, 4, 5, 6, 7];
+ let (prefix, aligned, suffix) = unsafe { bytes.align_to::<()>() };
+ assert_eq!(aligned.len(), 0);
+ assert!(prefix == [1, 2, 3, 4, 5, 6, 7] || suffix == [1, 2, 3, 4, 5, 6, 7]);
+}
+
+#[test]
+fn test_align_to_non_trivial() {
+ #[repr(align(8))]
+ struct U64(u64, u64);
+ #[repr(align(8))]
+ struct U64U64U32(u64, u64, u32);
+ let data = [
+ U64(1, 2),
+ U64(3, 4),
+ U64(5, 6),
+ U64(7, 8),
+ U64(9, 10),
+ U64(11, 12),
+ U64(13, 14),
+ U64(15, 16),
+ ];
+ let (prefix, aligned, suffix) = unsafe { data.align_to::<U64U64U32>() };
+ assert_eq!(aligned.len(), 4);
+ assert_eq!(prefix.len() + suffix.len(), 2);
+}
+
+#[test]
+fn test_align_to_empty_mid() {
+ use core::mem;
+
+ // Make sure that we do not create empty unaligned slices for the mid part, even when the
+ // overall slice is too short to contain an aligned address.
+ let bytes = [1, 2, 3, 4, 5, 6, 7];
+ type Chunk = u32;
+ for offset in 0..4 {
+ let (_, mid, _) = unsafe { bytes[offset..offset + 1].align_to::<Chunk>() };
+ assert_eq!(mid.as_ptr() as usize % mem::align_of::<Chunk>(), 0);
+ }
+}
+
+#[test]
+fn test_align_to_mut_aliasing() {
+ let mut val = [1u8, 2, 3, 4, 5];
+ // `align_to_mut` used to create `mid` in a way that there was some intermediate
+ // incorrect aliasing, invalidating the resulting `mid` slice.
+ let (begin, mid, end) = unsafe { val.align_to_mut::<[u8; 2]>() };
+ assert!(begin.len() == 0);
+ assert!(end.len() == 1);
+ mid[0] = mid[1];
+ assert_eq!(val, [3, 4, 3, 4, 5])
+}
+
+#[test]
+fn test_slice_partition_dedup_by() {
+ let mut slice: [i32; 9] = [1, -1, 2, 3, 1, -5, 5, -2, 2];
+
+ let (dedup, duplicates) = slice.partition_dedup_by(|a, b| a.abs() == b.abs());
+
+ assert_eq!(dedup, [1, 2, 3, 1, -5, -2]);
+ assert_eq!(duplicates, [5, -1, 2]);
+}
+
+#[test]
+fn test_slice_partition_dedup_empty() {
+ let mut slice: [i32; 0] = [];
+
+ let (dedup, duplicates) = slice.partition_dedup();
+
+ assert_eq!(dedup, []);
+ assert_eq!(duplicates, []);
+}
+
+#[test]
+fn test_slice_partition_dedup_one() {
+ let mut slice = [12];
+
+ let (dedup, duplicates) = slice.partition_dedup();
+
+ assert_eq!(dedup, [12]);
+ assert_eq!(duplicates, []);
+}
+
+#[test]
+fn test_slice_partition_dedup_multiple_ident() {
+ let mut slice = [12, 12, 12, 12, 12, 11, 11, 11, 11, 11, 11];
+
+ let (dedup, duplicates) = slice.partition_dedup();
+
+ assert_eq!(dedup, [12, 11]);
+ assert_eq!(duplicates, [12, 12, 12, 12, 11, 11, 11, 11, 11]);
+}
+
+#[test]
+fn test_slice_partition_dedup_partialeq() {
+ #[derive(Debug)]
+ struct Foo(i32, i32);
+
+ impl PartialEq for Foo {
+ fn eq(&self, other: &Foo) -> bool {
+ self.0 == other.0
+ }
+ }
+
+ let mut slice = [Foo(0, 1), Foo(0, 5), Foo(1, 7), Foo(1, 9)];
+
+ let (dedup, duplicates) = slice.partition_dedup();
+
+ assert_eq!(dedup, [Foo(0, 1), Foo(1, 7)]);
+ assert_eq!(duplicates, [Foo(0, 5), Foo(1, 9)]);
+}
+
+#[test]
+fn test_copy_within() {
+ // Start to end, with a RangeTo.
+ let mut bytes = *b"Hello, World!";
+ bytes.copy_within(..3, 10);
+ assert_eq!(&bytes, b"Hello, WorHel");
+
+ // End to start, with a RangeFrom.
+ let mut bytes = *b"Hello, World!";
+ bytes.copy_within(10.., 0);
+ assert_eq!(&bytes, b"ld!lo, World!");
+
+ // Overlapping, with a RangeInclusive.
+ let mut bytes = *b"Hello, World!";
+ bytes.copy_within(0..=11, 1);
+ assert_eq!(&bytes, b"HHello, World");
+
+ // Whole slice, with a RangeFull.
+ let mut bytes = *b"Hello, World!";
+ bytes.copy_within(.., 0);
+ assert_eq!(&bytes, b"Hello, World!");
+
+ // Ensure that copying at the end of slice won't cause UB.
+ let mut bytes = *b"Hello, World!";
+ bytes.copy_within(13..13, 5);
+ assert_eq!(&bytes, b"Hello, World!");
+ bytes.copy_within(5..5, 13);
+ assert_eq!(&bytes, b"Hello, World!");
+}
+
+#[test]
+#[should_panic(expected = "range end index 14 out of range for slice of length 13")]
+fn test_copy_within_panics_src_too_long() {
+ let mut bytes = *b"Hello, World!";
+ // The length is only 13, so 14 is out of bounds.
+ bytes.copy_within(10..14, 0);
+}
+
+#[test]
+#[should_panic(expected = "dest is out of bounds")]
+fn test_copy_within_panics_dest_too_long() {
+ let mut bytes = *b"Hello, World!";
+ // The length is only 13, so a slice of length 4 starting at index 10 is out of bounds.
+ bytes.copy_within(0..4, 10);
+}
+
+#[test]
+#[should_panic(expected = "slice index starts at 2 but ends at 1")]
+fn test_copy_within_panics_src_inverted() {
+ let mut bytes = *b"Hello, World!";
+ // 2 is greater than 1, so this range is invalid.
+ bytes.copy_within(2..1, 0);
+}
+#[test]
+#[should_panic(expected = "attempted to index slice up to maximum usize")]
+fn test_copy_within_panics_src_out_of_bounds() {
+ let mut bytes = *b"Hello, World!";
+ // an inclusive range ending at usize::MAX would make src_end overflow
+ bytes.copy_within(usize::MAX..=usize::MAX, 0);
+}
+
+#[test]
+fn test_is_sorted() {
+ let empty: [i32; 0] = [];
+
+ assert!([1, 2, 2, 9].is_sorted());
+ assert!(![1, 3, 2].is_sorted());
+ assert!([0].is_sorted());
+ assert!(empty.is_sorted());
+ assert!(![0.0, 1.0, f32::NAN].is_sorted());
+ assert!([-2, -1, 0, 3].is_sorted());
+ assert!(![-2i32, -1, 0, 3].is_sorted_by_key(|n| n.abs()));
+ assert!(!["c", "bb", "aaa"].is_sorted());
+ assert!(["c", "bb", "aaa"].is_sorted_by_key(|s| s.len()));
+}
+
+#[test]
+fn test_slice_run_destructors() {
+ // Make sure that destructors get run on slice literals
+ struct Foo<'a> {
+ x: &'a Cell<isize>,
+ }
+
+ impl<'a> Drop for Foo<'a> {
+ fn drop(&mut self) {
+ self.x.set(self.x.get() + 1);
+ }
+ }
+
+ fn foo(x: &Cell<isize>) -> Foo<'_> {
+ Foo { x }
+ }
+
+ let x = &Cell::new(0);
+
+ {
+ let l = &[foo(x)];
+ assert_eq!(l[0].x.get(), 0);
+ }
+
+ assert_eq!(x.get(), 1);
+}
+
+#[test]
+fn test_const_from_ref() {
+ const VALUE: &i32 = &1;
+ const SLICE: &[i32] = core::slice::from_ref(VALUE);
+
+ assert!(core::ptr::eq(VALUE, &SLICE[0]))
+}
+
+#[test]
+fn test_slice_fill_with_uninit() {
+ // This should not UB. See #87891
+ let mut a = [MaybeUninit::<u8>::uninit(); 10];
+ a.fill(MaybeUninit::uninit());
+}
+
+#[test]
+fn test_swap() {
+ let mut x = ["a", "b", "c", "d"];
+ x.swap(1, 3);
+ assert_eq!(x, ["a", "d", "c", "b"]);
+ x.swap(0, 3);
+ assert_eq!(x, ["b", "d", "c", "a"]);
+}
+
+mod swap_panics {
+ #[test]
+ #[should_panic(expected = "index out of bounds: the len is 4 but the index is 4")]
+ fn index_a_equals_len() {
+ let mut x = ["a", "b", "c", "d"];
+ x.swap(4, 2);
+ }
+
+ #[test]
+ #[should_panic(expected = "index out of bounds: the len is 4 but the index is 4")]
+ fn index_b_equals_len() {
+ let mut x = ["a", "b", "c", "d"];
+ x.swap(2, 4);
+ }
+
+ #[test]
+ #[should_panic(expected = "index out of bounds: the len is 4 but the index is 5")]
+ fn index_a_greater_than_len() {
+ let mut x = ["a", "b", "c", "d"];
+ x.swap(5, 2);
+ }
+
+ #[test]
+ #[should_panic(expected = "index out of bounds: the len is 4 but the index is 5")]
+ fn index_b_greater_than_len() {
+ let mut x = ["a", "b", "c", "d"];
+ x.swap(2, 5);
+ }
+}
+
+#[test]
+fn slice_split_array_mut() {
+ let v = &mut [1, 2, 3, 4, 5, 6][..];
+
+ {
+ let (left, right) = v.split_array_mut::<0>();
+ assert_eq!(left, &mut []);
+ assert_eq!(right, [1, 2, 3, 4, 5, 6]);
+ }
+
+ {
+ let (left, right) = v.split_array_mut::<6>();
+ assert_eq!(left, &mut [1, 2, 3, 4, 5, 6]);
+ assert_eq!(right, []);
+ }
+}
+
+#[test]
+fn slice_rsplit_array_mut() {
+ let v = &mut [1, 2, 3, 4, 5, 6][..];
+
+ {
+ let (left, right) = v.rsplit_array_mut::<0>();
+ assert_eq!(left, [1, 2, 3, 4, 5, 6]);
+ assert_eq!(right, &mut []);
+ }
+
+ {
+ let (left, right) = v.rsplit_array_mut::<6>();
+ assert_eq!(left, []);
+ assert_eq!(right, &mut [1, 2, 3, 4, 5, 6]);
+ }
+}
+
+#[test]
+fn split_as_slice() {
+ let arr = [1, 2, 3, 4, 5, 6];
+ let mut split = arr.split(|v| v % 2 == 0);
+ assert_eq!(split.as_slice(), &[1, 2, 3, 4, 5, 6]);
+ assert!(split.next().is_some());
+ assert_eq!(split.as_slice(), &[3, 4, 5, 6]);
+ assert!(split.next().is_some());
+ assert!(split.next().is_some());
+ assert_eq!(split.as_slice(), &[]);
+}
+
+#[should_panic]
+#[test]
+fn slice_split_array_ref_out_of_bounds() {
+ let v = &[1, 2, 3, 4, 5, 6][..];
+
+ let _ = v.split_array_ref::<7>();
+}
+
+#[should_panic]
+#[test]
+fn slice_split_array_mut_out_of_bounds() {
+ let v = &mut [1, 2, 3, 4, 5, 6][..];
+
+ let _ = v.split_array_mut::<7>();
+}
+
+#[should_panic]
+#[test]
+fn slice_rsplit_array_ref_out_of_bounds() {
+ let v = &[1, 2, 3, 4, 5, 6][..];
+
+ let _ = v.rsplit_array_ref::<7>();
+}
+
+#[should_panic]
+#[test]
+fn slice_rsplit_array_mut_out_of_bounds() {
+ let v = &mut [1, 2, 3, 4, 5, 6][..];
+
+ let _ = v.rsplit_array_mut::<7>();
+}
+
+macro_rules! take_tests {
+ (slice: &[], $($tts:tt)*) => {
+ take_tests!(ty: &[()], slice: &[], $($tts)*);
+ };
+ (slice: &mut [], $($tts:tt)*) => {
+ take_tests!(ty: &mut [()], slice: &mut [], $($tts)*);
+ };
+ (slice: &$slice:expr, $($tts:tt)*) => {
+ take_tests!(ty: &[_], slice: &$slice, $($tts)*);
+ };
+ (slice: &mut $slice:expr, $($tts:tt)*) => {
+ take_tests!(ty: &mut [_], slice: &mut $slice, $($tts)*);
+ };
+ (ty: $ty:ty, slice: $slice:expr, method: $method:ident, $(($test_name:ident, ($($args:expr),*), $output:expr, $remaining:expr),)*) => {
+ $(
+ #[test]
+ fn $test_name() {
+ let mut slice: $ty = $slice;
+ assert_eq!($output, slice.$method($($args)*));
+ let remaining: $ty = $remaining;
+ assert_eq!(remaining, slice);
+ }
+ )*
+ };
+}
+
+take_tests! {
+ slice: &[0, 1, 2, 3], method: take,
+ (take_in_bounds_range_to, (..1), Some(&[0] as _), &[1, 2, 3]),
+ (take_in_bounds_range_to_inclusive, (..=0), Some(&[0] as _), &[1, 2, 3]),
+ (take_in_bounds_range_from, (2..), Some(&[2, 3] as _), &[0, 1]),
+ (take_oob_range_to, (..5), None, &[0, 1, 2, 3]),
+ (take_oob_range_to_inclusive, (..=4), None, &[0, 1, 2, 3]),
+ (take_oob_range_from, (5..), None, &[0, 1, 2, 3]),
+}
+
+take_tests! {
+ slice: &mut [0, 1, 2, 3], method: take_mut,
+ (take_mut_in_bounds_range_to, (..1), Some(&mut [0] as _), &mut [1, 2, 3]),
+ (take_mut_in_bounds_range_to_inclusive, (..=0), Some(&mut [0] as _), &mut [1, 2, 3]),
+ (take_mut_in_bounds_range_from, (2..), Some(&mut [2, 3] as _), &mut [0, 1]),
+ (take_mut_oob_range_to, (..5), None, &mut [0, 1, 2, 3]),
+ (take_mut_oob_range_to_inclusive, (..=4), None, &mut [0, 1, 2, 3]),
+ (take_mut_oob_range_from, (5..), None, &mut [0, 1, 2, 3]),
+}
+
+take_tests! {
+ slice: &[1, 2], method: take_first,
+ (take_first_nonempty, (), Some(&1), &[2]),
+}
+
+take_tests! {
+ slice: &mut [1, 2], method: take_first_mut,
+ (take_first_mut_nonempty, (), Some(&mut 1), &mut [2]),
+}
+
+take_tests! {
+ slice: &[1, 2], method: take_last,
+ (take_last_nonempty, (), Some(&2), &[1]),
+}
+
+take_tests! {
+ slice: &mut [1, 2], method: take_last_mut,
+ (take_last_mut_nonempty, (), Some(&mut 2), &mut [1]),
+}
+
+take_tests! {
+ slice: &[], method: take_first,
+ (take_first_empty, (), None, &[]),
+}
+
+take_tests! {
+ slice: &mut [], method: take_first_mut,
+ (take_first_mut_empty, (), None, &mut []),
+}
+
+take_tests! {
+ slice: &[], method: take_last,
+ (take_last_empty, (), None, &[]),
+}
+
+take_tests! {
+ slice: &mut [], method: take_last_mut,
+ (take_last_mut_empty, (), None, &mut []),
+}
+
+#[cfg(not(miri))] // unused in Miri
+const EMPTY_MAX: &'static [()] = &[(); usize::MAX];
+
+// can't be a constant due to const mutability rules
+#[cfg(not(miri))] // unused in Miri
+macro_rules! empty_max_mut {
+ () => {
+ &mut [(); usize::MAX] as _
+ };
+}
+
+#[cfg(not(miri))] // Comparing usize::MAX many elements takes forever in Miri (and in rustc without optimizations)
+take_tests! {
+ slice: &[(); usize::MAX], method: take,
+ (take_in_bounds_max_range_to, (..usize::MAX), Some(EMPTY_MAX), &[(); 0]),
+ (take_oob_max_range_to_inclusive, (..=usize::MAX), None, EMPTY_MAX),
+ (take_in_bounds_max_range_from, (usize::MAX..), Some(&[] as _), EMPTY_MAX),
+}
+
+#[cfg(not(miri))] // Comparing usize::MAX many elements takes forever in Miri (and in rustc without optimizations)
+take_tests! {
+ slice: &mut [(); usize::MAX], method: take_mut,
+ (take_mut_in_bounds_max_range_to, (..usize::MAX), Some(empty_max_mut!()), &mut [(); 0]),
+ (take_mut_oob_max_range_to_inclusive, (..=usize::MAX), None, empty_max_mut!()),
+ (take_mut_in_bounds_max_range_from, (usize::MAX..), Some(&mut [] as _), empty_max_mut!()),
+}
+
+#[test]
+fn test_slice_from_ptr_range() {
+ let arr = ["foo".to_owned(), "bar".to_owned()];
+ let range = arr.as_ptr_range();
+ unsafe {
+ assert_eq!(slice::from_ptr_range(range), &arr);
+ }
+
+ let mut arr = [1, 2, 3];
+ let range = arr.as_mut_ptr_range();
+ unsafe {
+ assert_eq!(slice::from_mut_ptr_range(range), &mut [1, 2, 3]);
+ }
+
+ let arr: [Vec<String>; 0] = [];
+ let range = arr.as_ptr_range();
+ unsafe {
+ assert_eq!(slice::from_ptr_range(range), &arr);
+ }
+}
+
+#[test]
+#[should_panic = "slice len overflow"]
+fn test_flatten_size_overflow() {
+ let x = &[[(); usize::MAX]; 2][..];
+ let _ = x.flatten();
+}
+
+#[test]
+#[should_panic = "slice len overflow"]
+fn test_flatten_mut_size_overflow() {
+ let x = &mut [[(); usize::MAX]; 2][..];
+ let _ = x.flatten_mut();
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-07-26 14:14:58 +0000