NarrowT CheckedNarrowing(const WideT& wide) {
  NarrowT narrow = wide;
  CHECK_EQ(narrow, wide)
      << "checked narrowing failed; values not equal post-conversion";
  return narrow;
}
NarrowT CheckedNarrowing(const WideT& wide) {
  NarrowT narrow = wide;
  CHECK_EQ(narrow, wide)
      << "checked narrowing failed; values not equal post-conversion";
  return narrow;
}