public void invalidate() {
    if (myType == VIRTUAL_FILES) {
      List<? extends VirtualFile> valid = ContainerUtil.filter(myVFiles, virtualFile -> virtualFile != null && virtualFile.isValid());
      VirtualFileSet files = VfsUtilCore.createCompactVirtualFileSet(valid);
      files.freeze();
      myVFiles = files;
    }
    myFilesSet = null;
  }
public void invalidate()