diff --git a/src/vt/utils/adt/union.h b/src/vt/utils/adt/union.h
index 9c2b0741d4..a0b37fb445 100644
--- a/src/vt/utils/adt/union.h
+++ b/src/vt/utils/adt/union.h
@@ -291,6 +291,7 @@ struct AlignedCharUnion {
    */
   template <typename U>
   bool is() {
+    staticAssertCorrectness<U>();
     return which_ == detail::Which<U, T, Ts...>::value;
   }