diff --git a/test/cpp/qps/client_async.cc b/test/cpp/qps/client_async.cc
index 43f037ce480f4285ae59f4f48dab79651f4c6128..5d9cb4bd0cfc35eeecf9db4310a5e6115e70ec86 100644
--- a/test/cpp/qps/client_async.cc
+++ b/test/cpp/qps/client_async.cc
@@ -265,6 +265,7 @@ class AsyncClient : public ClientImpl<StubType, RequestType> {
                                        // done
         return true;
     }
+    GPR_UNREACHABLE_CODE(return true);
   }
 
   std::vector<std::unique_ptr<CompletionQueue>> cli_cqs_;