Class key_equal

tests/ordered_map_tests.cpp:1490–1502

  };

  struct key_equal {
    bool operator()(std::uint64_t lhs, std::uint64_t rhs) const {
      if (lhs % 2u == 1u) {
        lhs--;
      }

      if (rhs % 2u == 1u) {
        rhs--;
      }

      return lhs == rhs;
    }
  };

  tsl::ordered_map<std::uint64_t, std::uint64_t, hash, key_equal> map;
  BOOST_CHECK(map.insert({2, 10}).second);