diff --git a/src/collections/string_pool.rs b/src/collections/string_pool.rs
index ad281e630f0bba4c2d192f01f878509d7ae1b0cf..58fc38bd5524f9abf76135fc40b9d3f4066d414f 100644
--- a/src/collections/string_pool.rs
+++ b/src/collections/string_pool.rs
@@ -171,7 +171,7 @@ mod tests {
     fn display_empty_string_ref() {
         // Makes sure that null pointer inside StringRef will not cause issues
         let v = StringRef::new_empty();
-        let val = format!("{}{:?}", v, v);
+        let _val = format!("{}{:?}", v, v); // calls Format and Debug on StringRef
     }
 
     #[test]