diff --git a/src/nunavut/lang/cpp/templates/_fields_as_union.j2 b/src/nunavut/lang/cpp/templates/_fields_as_union.j2
index 64cb6276..10178226 100644
--- a/src/nunavut/lang/cpp/templates/_fields_as_union.j2
+++ b/src/nunavut/lang/cpp/templates/_fields_as_union.j2
@@ -49,6 +49,7 @@
             : tag_{I}
             , internal_union_value_{}
         {
+            (void)i; //avoid unused param warning
             do_emplace<I>(std::forward<Args>(args)...);
         }
 
diff --git a/src/nunavut/lang/cpp/templates/_fields_as_variant.j2 b/src/nunavut/lang/cpp/templates/_fields_as_variant.j2
index 402c7884..2dab13b4 100644
--- a/src/nunavut/lang/cpp/templates/_fields_as_variant.j2
+++ b/src/nunavut/lang/cpp/templates/_fields_as_variant.j2
@@ -59,7 +59,7 @@
         VariantType(nunavut::support::in_place_index_t<I> i, Args&&... args) :
             Base{std::in_place_index_t<I>{}, std::forward<Args>(args)...}
         {
-            (void)i; // avoid unused param
+            (void)i; // avoid unused param warning
         }
 
         // Copy constructor