diff --git a/platform/script-debugger/backend/src/org/jetbrains/rpc/CommandSenderBase.java b/platform/script-debugger/backend/src/org/jetbrains/rpc/CommandSenderBase.java
index e7a1bb82e122..53351e30277d 100644
--- a/platform/script-debugger/backend/src/org/jetbrains/rpc/CommandSenderBase.java
+++ b/platform/script-debugger/backend/src/org/jetbrains/rpc/CommandSenderBase.java
@@ -27,7 +27,7 @@ public abstract class CommandSenderBase<SUCCESS_RESPONSE, ERROR_DETAILS> impleme
     return callback;
   }
 
-  private static final class PromiseWrapper<SUCCESS_RESPONSE, RESULT, ERROR_DETAILS> extends AsyncPromise<RESULT> implements AsyncResultCallback<SUCCESS_RESPONSE, ERROR_DETAILS> {
+  protected static final class PromiseWrapper<SUCCESS_RESPONSE, RESULT, ERROR_DETAILS> extends AsyncPromise<RESULT> implements AsyncResultCallback<SUCCESS_RESPONSE, ERROR_DETAILS> {
     private final String methodName;
 
     public PromiseWrapper(@Nullable String methodName) {