static void assertCorrectOriginalFile(@NonNls String prefix, PsiFile file, PsiFile copy) {
    if (copy.getOriginalFile() != file) {
      throw new AssertionError(prefix + " copied file doesn't have correct original: noOriginal=" + (copy.getOriginalFile() == copy) +
                               "\n file " + fileInfo(file) +
                               "\n copy " + fileInfo(copy));
    }
  }
static void assertCorrectOriginalFile(@NonNls String prefix, PsiFile file, PsiFile copy)