diff --git a/src/ReactTestHostConfig.js b/src/ReactTestHostConfig.js
index 5f5de45..e6df01d 100644
--- a/src/ReactTestHostConfig.js
+++ b/src/ReactTestHostConfig.js
@@ -296,7 +296,6 @@ export function mountResponderInstance(
   props: Object,
   state: Object,
   instance: Instance,
-  rootContainerInstance: Container,
 ) {
   // noop
 }