1 files changed, 36 insertions, 0 deletions
diff --git a/src/tools/clippy/tests/ui/manual_next_back.rs b/src/tools/clippy/tests/ui/manual_next_back.rs
new file mode 100644
index 00000000000..9ec89242241
--- /dev/null
+++ b/src/tools/clippy/tests/ui/manual_next_back.rs
@@ -0,0 +1,36 @@
+//@run-rustfix
+
+#![allow(unused)]
+#![warn(clippy::manual_next_back)]
+
+struct FakeIter(std::ops::Range<i32>);
+
+impl FakeIter {
+    fn rev(self) -> Self {
+        self
+    }
+
+    fn next(&self) {}
+}
+
+impl DoubleEndedIterator for FakeIter {
+    fn next_back(&mut self) -> Option<Self::Item> {
+        self.0.next_back()
+    }
+}
+
+impl Iterator for FakeIter {
+    type Item = i32;
+    fn next(&mut self) -> Option<Self::Item> {
+        self.0.next()
+    }
+}
+
+fn main() {
+    // should not lint
+    FakeIter(0..10).rev().next();
+
+    // should lint
+    let _ = (0..10).rev().next().unwrap();
+    let _ = "something".bytes().rev().next();
+}