1 files changed, 63 insertions, 0 deletions
diff --git a/src/tools/clippy/tests/ui/iter_on_empty_collections.fixed b/src/tools/clippy/tests/ui/iter_on_empty_collections.fixed
new file mode 100644
index 000000000..bd9b07aef
--- /dev/null
+++ b/src/tools/clippy/tests/ui/iter_on_empty_collections.fixed
@@ -0,0 +1,63 @@
+// run-rustfix
+#![warn(clippy::iter_on_empty_collections)]
+#![allow(clippy::iter_next_slice, clippy::redundant_clone)]
+
+fn array() {
+    assert_eq!(std::iter::empty().next(), Option::<i32>::None);
+    assert_eq!(std::iter::empty().next(), Option::<&mut i32>::None);
+    assert_eq!(std::iter::empty().next(), Option::<&i32>::None);
+    assert_eq!(std::iter::empty().next(), Option::<i32>::None);
+    assert_eq!(std::iter::empty().next(), Option::<&mut i32>::None);
+    assert_eq!(std::iter::empty().next(), Option::<&i32>::None);
+
+    // Don't trigger on non-iter methods
+    let _: Option<String> = None.clone();
+    let _: [String; 0] = [].clone();
+
+    // Don't trigger on match or if branches
+    let _ = match 123 {
+        123 => [].iter(),
+        _ => ["test"].iter(),
+    };
+
+    let _ = if false { ["test"].iter() } else { [].iter() };
+}
+
+macro_rules! in_macros {
+    () => {
+        assert_eq!([].into_iter().next(), Option::<i32>::None);
+        assert_eq!([].iter_mut().next(), Option::<&mut i32>::None);
+        assert_eq!([].iter().next(), Option::<&i32>::None);
+        assert_eq!(None.into_iter().next(), Option::<i32>::None);
+        assert_eq!(None.iter_mut().next(), Option::<&mut i32>::None);
+        assert_eq!(None.iter().next(), Option::<&i32>::None);
+    };
+}
+
+// Don't trigger on a `None` that isn't std's option
+mod custom_option {
+    #[allow(unused)]
+    enum CustomOption {
+        Some(i32),
+        None,
+    }
+
+    impl CustomOption {
+        fn iter(&self) {}
+        fn iter_mut(&mut self) {}
+        fn into_iter(self) {}
+    }
+    use CustomOption::*;
+
+    pub fn custom_option() {
+        None.iter();
+        None.iter_mut();
+        None.into_iter();
+    }
+}
+
+fn main() {
+    array();
+    custom_option::custom_option();
+    in_macros!();
+}