diff --git a/gc/src/gc.rs b/gc/src/gc.rs
index 9526c28..244022e 100644
--- a/gc/src/gc.rs
+++ b/gc/src/gc.rs
@@ -160,7 +160,7 @@ impl<
 
             // Create a pointer with the metadata of value and the
             // address and provenance of the GcBox.
-            let gcbox = set_data_ptr(value as *mut GcBox<T>, gcbox_addr);
+            let gcbox = set_data_ptr(value.cast::<GcBox<T>>(), gcbox_addr);
 
             // Move the data.
             ptr::addr_of_mut!((*gcbox).header).write(GcBoxHeader::new());