From a236172467c88179f4a3a95888735082d1ea6c95 Mon Sep 17 00:00:00 2001
From: Zachary Dremann <dremann@gmail.com>
Date: Sun, 28 Jan 2024 03:06:27 -0500
Subject: [PATCH] Try to find empty subbitmaps in treemap

---
 croaring/src/treemap/iter.rs             | 6 +++++-
 fuzz/fuzz_targets/arbitrary_ops64/mod.rs | 2 +-
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/croaring/src/treemap/iter.rs b/croaring/src/treemap/iter.rs
index d25504a..ef767d1 100644
--- a/croaring/src/treemap/iter.rs
+++ b/croaring/src/treemap/iter.rs
@@ -39,7 +39,11 @@ pub struct TreemapIterator<'a> {
 
 impl<'a> TreemapIterator<'a> {
     fn new(treemap: &'a Treemap) -> Self {
-        let iter = treemap.map.iter().flat_map(to64iter as _);
+        let iter = treemap
+            .map
+            .iter()
+            .inspect(|(key, bitmap)| assert!(!bitmap.is_empty(), "empty bitmap at {key}"))
+            .flat_map(to64iter as _);
 
         TreemapIterator { iter }
     }
diff --git a/fuzz/fuzz_targets/arbitrary_ops64/mod.rs b/fuzz/fuzz_targets/arbitrary_ops64/mod.rs
index c923ae2..47b31d9 100644
--- a/fuzz/fuzz_targets/arbitrary_ops64/mod.rs
+++ b/fuzz/fuzz_targets/arbitrary_ops64/mod.rs
@@ -417,7 +417,7 @@ pub fn assert_64_eq(lhs: &Bitmap64, rhs: &Treemap) {
             let r = rhs.next().unwrap();
             assert_eq!(l, r, "{l} != {r} at {i}");
         }
-        assert!(rhs.next().is_none());
+        assert_eq!(rhs.next(), None);
         panic!("Serialize not equal, but all items equal?")
     }
 }