private void addTrace(@Nullable PsiClassStub<?> stub) {
    if (ourTraceStubAstBinding) {
      String creationTrace = "Creation thread: " + Thread.currentThread() + "\n" + DebugUtil.currentStackTrace();
      if (stub != null) {
        creationTrace += "\nfrom stub " + stub + "@" + System.identityHashCode(stub) + "\n";
        if (stub instanceof UserDataHolder) {
          String stubTrace = ((UserDataHolder)stub).getUserData(CREATION_TRACE);
          if (stubTrace != null) {
            creationTrace += stubTrace;
          }
        }
      }
      putUserData(CREATION_TRACE, creationTrace);
    }
  }
private void addTrace(@Nullable PsiClassStub<?> stub)