diff --git a/external/vulkancts/modules/vulkan/memory_model/vktMemoryModelMessagePassing.cpp b/external/vulkancts/modules/vulkan/memory_model/vktMemoryModelMessagePassing.cpp
index 3bc2738..fcae572 100644
--- a/external/vulkancts/modules/vulkan/memory_model/vktMemoryModelMessagePassing.cpp
+++ b/external/vulkancts/modules/vulkan/memory_model/vktMemoryModelMessagePassing.cpp
@@ -233,6 +233,7 @@
 	const char *scopeStr;
 	switch (m_data.scope)
 	{
+	default: DE_ASSERT(0); // fall through
 	case SCOPE_DEVICE:		scopeStr = "gl_ScopeDevice"; break;
 	case SCOPE_QUEUEFAMILY:	scopeStr = "gl_ScopeQueueFamily"; break;
 	case SCOPE_WORKGROUP:	scopeStr = "gl_ScopeWorkgroup"; break;