diff --git a/platform/core-api/src/org/jetbrains/concurrency/DonePromise.java b/platform/core-api/src/org/jetbrains/concurrency/DonePromise.java
index e69725bcf6c6..7f0d143d332f 100644
--- a/platform/core-api/src/org/jetbrains/concurrency/DonePromise.java
+++ b/platform/core-api/src/org/jetbrains/concurrency/DonePromise.java
@@ -41,9 +41,9 @@ class DonePromise<T> extends InternalPromiseUtil.BasePromise<T> {
       //noinspection unchecked
       ((InternalPromiseUtil.PromiseImpl<T>)child)._setValue(value);
     }
-    else if (child instanceof Promise.CompletablePromise) {
+    else if (child instanceof InternalPromiseUtil.CompletablePromise) {
       //noinspection unchecked
-      ((CompletablePromise<T>)child).setResult(value.result);
+      ((InternalPromiseUtil.CompletablePromise<T>)child).setResult(value.result);
     }
     return this;
   }
diff --git a/platform/core-api/src/org/jetbrains/concurrency/InternalPromiseUtil.java b/platform/core-api/src/org/jetbrains/concurrency/InternalPromiseUtil.java
index fb343abe3459..963c640a50ef 100644
--- a/platform/core-api/src/org/jetbrains/concurrency/InternalPromiseUtil.java
+++ b/platform/core-api/src/org/jetbrains/concurrency/InternalPromiseUtil.java
@@ -42,6 +42,11 @@ public class InternalPromiseUtil {
     void _setValue(@NotNull PromiseValue<T> value);
   }
 
+  public interface CompletablePromise<T> extends Promise<T> {
+    void setResult(@Nullable T t);
+    boolean setError(@NotNull Throwable error);
+  }
+
   @SuppressWarnings("ExceptionClassNameDoesntEndWithException")
   public static class MessageError extends RuntimeException {
     public final ThreeState log;
diff --git a/platform/core-api/src/org/jetbrains/concurrency/Promise.java b/platform/core-api/src/org/jetbrains/concurrency/Promise.java
index 6e13fbbcb387..c28fa2246c55 100644
--- a/platform/core-api/src/org/jetbrains/concurrency/Promise.java
+++ b/platform/core-api/src/org/jetbrains/concurrency/Promise.java
@@ -143,9 +143,4 @@ public interface Promise<T> {
   default boolean isSucceeded() {
     return getState() == State.SUCCEEDED;
   }
-
-  interface CompletablePromise<T> extends Promise<T> {
-    void setResult(@Nullable T t);
-    boolean setError(@NotNull Throwable error);
-  }
 }
\ No newline at end of file
diff --git a/platform/projectModel-api/src/org/jetbrains/concurrency/AsyncPromise.kt b/platform/projectModel-api/src/org/jetbrains/concurrency/AsyncPromise.kt
index 814f263de694..a40096a28878 100644
--- a/platform/projectModel-api/src/org/jetbrains/concurrency/AsyncPromise.kt
+++ b/platform/projectModel-api/src/org/jetbrains/concurrency/AsyncPromise.kt
@@ -7,7 +7,7 @@ import org.jetbrains.concurrency.Promise.State
 import java.util.concurrent.*
 import java.util.function.Consumer
 
-open class AsyncPromise<T> : CancellablePromise<T>, Promise.CompletablePromise<T> {
+open class AsyncPromise<T> : CancellablePromise<T>, InternalPromiseUtil.CompletablePromise<T> {
   private val f: CompletableFuture<T>
 
   constructor() {