diff --git a/library/alloc/src/collections/btree/node.rs b/library/alloc/src/collections/btree/node.rs
index c3f27c10599..ba08f65f903 100644
--- a/library/alloc/src/collections/btree/node.rs
+++ b/library/alloc/src/collections/btree/node.rs
@@ -128,7 +128,7 @@ impl<K, V> BoxedNode<K, V> {
     }
 
     fn from_internal(node: Box<InternalNode<K, V>>) -> Self {
-        BoxedNode { ptr: Box::into_unique(node).cast() }
+        BoxedNode { ptr: Unique::from(&mut Box::leak(node).data) }
     }
 
     unsafe fn from_ptr(ptr: NonNull<LeafNode<K, V>>) -> Self {