constexpr E error_or()

in src/iceberg/expected.h [1465:1475]

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

  constexpr E error_or(G&& v) const&  //
      noexcept(std::is_nothrow_copy_constructible_v<E> &&
               expected_detail::is_nothrow_convertible_v<G, E>) {
    static_assert(std::is_copy_constructible_v<E>, "E must be copy-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 this->m_unexpect;
    }
  }