diff --git a/src/backing/indexed/binary_heap.rs b/src/backing/indexed/binary_heap.rs
index 9c69025..05c73e6 100644
--- a/src/backing/indexed/binary_heap.rs
+++ b/src/backing/indexed/binary_heap.rs
@@ -124,8 +124,12 @@ impl<D: Hash + Eq + Clone + Send + Sync, P: PartialOrd + Clone + Send + Sync> Fr
     fn from_iter<T: IntoIterator<Item = (D, P)>>(iter: T) -> Self {
         let mut this = Self::new();
         for (i, (data, priority)) in iter.into_iter().enumerate() {
-            this.indices.insert(data.clone(), i);
-            this.data.push(Pair::new(data, priority));
+            if let Some(prev) = this.indices.insert(data.clone(), i) {
+                this.indices.insert(data.clone(), prev).unwrap();
+                this.data[prev] = Pair::new(data, priority);
+            } else {
+                this.data.push(Pair::new(data, priority));
+            }
         }
         for i in (0..=(this.data.len() / 2)).rev() {
             this.sift_down(i).expect("Index error during heapify");