Rollup merge of rust-lang#138016 - nwoods-cimpress:slice_chunkby_clone, r=dtolnay

Added `Clone` implementation for `ChunkBy`

Added `Clone` implementation for `ChunkBy`

Closes rust-lang#137969.

Author: matthiaskrgr

library/alloctests/tests/slice.rs

@@ -1636,6 +1636,19 @@ fn test_chunk_by() {
     assert_eq!(iter.next_back(), Some(&[1][..]));
     assert_eq!(iter.next(), Some(&[2, 2, 2][..]));
     assert_eq!(iter.next_back(), None);
+
+    let mut iter = slice.chunk_by(|a, b| a == b);
+    assert_eq!(iter.next(), Some(&[1, 1, 1][..]));
+    assert_eq!(iter.next(), Some(&[3, 3][..]));
+    let mut iter_clone = iter.clone();
+    assert_eq!(iter.next(), Some(&[2, 2, 2][..]));
+    assert_eq!(iter.next(), Some(&[1][..]));
+    assert_eq!(iter.next(), Some(&[0][..]));
+    assert_eq!(iter.next(), None);
+    assert_eq!(iter_clone.next(), Some(&[2, 2, 2][..]));
+    assert_eq!(iter_clone.next(), Some(&[1][..]));
+    assert_eq!(iter_clone.next(), Some(&[0][..]));
+    assert_eq!(iter_clone.next(), None);
 }
 
 #[test]

library/core/src/slice/iter.rs

@@ -3376,6 +3376,13 @@ where
 #[stable(feature = "slice_group_by", since = "1.77.0")]
 impl<'a, T: 'a, P> FusedIterator for ChunkBy<'a, T, P> where P: FnMut(&T, &T) -> bool {}
 
+#[stable(feature = "slice_group_by_clone", since = "CURRENT_RUSTC_VERSION")]
+impl<'a, T: 'a, P: Clone> Clone for ChunkBy<'a, T, P> {
+    fn clone(&self) -> Self {
+        Self { slice: self.slice, predicate: self.predicate.clone() }
+    }
+}
+
 #[stable(feature = "slice_group_by", since = "1.77.0")]
 impl<'a, T: 'a + fmt::Debug, P> fmt::Debug for ChunkBy<'a, T, P> {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {