1 files changed, 21 insertions, 0 deletions
diff --git a/src/tools/clippy/tests/ui/copy_iterator.rs b/src/tools/clippy/tests/ui/copy_iterator.rs
new file mode 100644
index 000000000..ae67ebded
--- /dev/null
+++ b/src/tools/clippy/tests/ui/copy_iterator.rs
@@ -0,0 +1,21 @@
+#![warn(clippy::copy_iterator)]
+
+#[derive(Copy, Clone)]
+struct Countdown(u8);
+
+impl Iterator for Countdown {
+    type Item = u8;
+
+    fn next(&mut self) -> Option<u8> {
+        self.0.checked_sub(1).map(|c| {
+            self.0 = c;
+            c
+        })
+    }
+}
+
+fn main() {
+    let my_iterator = Countdown(5);
+    assert_eq!(my_iterator.take(1).count(), 1);
+    assert_eq!(my_iterator.count(), 5);
+}