private static @NotNull LightVirtualFile getCopy(@NotNull LightVirtualFile original) {
    VirtualFile parent = original.getParent();
    return new LightVirtualFile(original, original.getContent(), original.getModificationStamp()) {
      @Override
      public VirtualFile getParent() {
        return parent;
      }
    };
  }
private static @NotNull LightVirtualFile getCopy(@NotNull LightVirtualFile original)