diff --git a/javaslang/src/main/java/javaslang/collection/HashArrayMappedTrie.java b/javaslang/src/main/java/javaslang/collection/HashArrayMappedTrie.java
index 40020380a2..7c0b6e4458 100644
--- a/javaslang/src/main/java/javaslang/collection/HashArrayMappedTrie.java
+++ b/javaslang/src/main/java/javaslang/collection/HashArrayMappedTrie.java
@@ -287,7 +287,7 @@ final class LeafSingleton<K, V> extends LeafNode<K, V> implements Serializable {
 
         @Override
         Option<V> lookup(int shift, int keyHashCode, K key) {
-            if (Objects.equals(key, this.key)) {
+            if (keyHashCode == hash && Objects.equals(key, this.key)) {
                 return Option.some(value);
             } else {
                 return Option.none();
@@ -296,7 +296,7 @@ Option<V> lookup(int shift, int keyHashCode, K key) {
 
         @Override
         AbstractNode<K, V> modify(int shift, int keyHashCode, K key, V value, Action action) {
-            if (Objects.equals(key, this.key)) {
+            if (keyHashCode == hash && Objects.equals(key, this.key)) {
                 return (action == REMOVE) ? EmptyNode.instance() : new LeafSingleton<>(hash, key, value);
             } else {
                 return (action == REMOVE) ? this : mergeLeaves(shift, this, new LeafSingleton<>(keyHashCode, key, value));