From 890fb130e8855ca617e5f9e55c4c5bb3f08bc3fe Mon Sep 17 00:00:00 2001
From: Laurence Tratt <laurie@tratt.net>
Date: Tue, 8 Jul 2025 16:04:27 +0100
Subject: [PATCH] Implement `FusedIterator` for `Iter{Set,Unset}Bits`

---
 src/lib.rs | 21 ++++++++++++++++++++-
 1 file changed, 20 insertions(+), 1 deletion(-)

diff --git a/src/lib.rs b/src/lib.rs
index 099cbeb..8b16615 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -7,7 +7,7 @@ use std::{
     cmp::{min, PartialEq},
     fmt::{self, Debug},
     hash::{Hash, Hasher},
-    iter::{DoubleEndedIterator, FromIterator},
+    iter::{DoubleEndedIterator, FromIterator, FusedIterator},
     mem::{replace, size_of},
     ops::{
         Bound::{Excluded, Included, Unbounded},
@@ -1182,6 +1182,8 @@ impl<T: Debug + PrimInt> DoubleEndedIterator for IterSetBits<'_, T> {
     }
 }
 
+impl<T: Debug + PrimInt> FusedIterator for IterSetBits<'_, T> {}
+
 #[derive(Clone)]
 pub struct IterUnsetBits<'a, T: 'a> {
     vob: &'a Vob<T>,
@@ -1260,6 +1262,8 @@ impl<T: Debug + PrimInt> DoubleEndedIterator for IterUnsetBits<'_, T> {
     }
 }
 
+impl<T: Debug + PrimInt> FusedIterator for IterUnsetBits<'_, T> {}
+
 impl<T: Debug + PrimInt> PartialEq for Vob<T> {
     fn eq(&self, other: &Self) -> bool {
         if self.len != other.len {
@@ -1914,6 +1918,21 @@ mod tests {
         t(&v1, 128.., vec![129, 130, 256]);
     }
 
+    #[test]
+    fn test_fused() {
+        let v1 = vob![true];
+        let mut i1 = v1.iter_set_bits(..);
+        assert!(i1.next().is_some());
+        assert!(i1.next().is_none());
+        assert!(i1.next().is_none());
+
+        let v2 = vob![false];
+        let mut i2 = v2.iter_unset_bits(..);
+        assert!(i2.next().is_some());
+        assert!(i2.next().is_none());
+        assert!(i2.next().is_none());
+    }
+
     #[test]
     fn test_eq() {
         let v1 = Vob::from_iter(vec![true, false]);