diff --git a/neuralnetworks/1.0/vts/functional/GeneratedTestHarness.cpp b/neuralnetworks/1.0/vts/functional/GeneratedTestHarness.cpp
index cc19978..464fc14 100644
--- a/neuralnetworks/1.0/vts/functional/GeneratedTestHarness.cpp
+++ b/neuralnetworks/1.0/vts/functional/GeneratedTestHarness.cpp
@@ -62,6 +62,8 @@
     copy_back_<float>(dst, ra, src);
     copy_back_<int32_t>(dst, ra, src);
     copy_back_<uint8_t>(dst, ra, src);
+    static_assert(3 == std::tuple_size<MixedTyped>::value,
+                  "Number of types in MixedTyped changed, but copy_back function wasn't updated");
 }
 
 // Top level driver for models and examples generated by test_generator.py