constexpr E error_or()

in src/iceberg/expected.h [1477:1487]

• 11 lines of code
• 5 McCabe index (conditional complexity)

  constexpr E error_or(G&& v) &&  //
      noexcept(std::is_nothrow_move_constructible_v<E> &&
               expected_detail::is_nothrow_convertible_v<G, E>) {
    static_assert(std::is_move_constructible_v<E>, "E must be move-constructible");
    static_assert(std::is_convertible_v<G, E>, "is_convertible_v<G, E> must be true");
    if (this->m_has_val) {
      return static_cast<E>(std::forward<G>(v));
    } else {
      return std::move(this->m_unexpect);
    }
  }