message: Fix sentinel type for the second range in the constructor.
diff: @@ -167,7 +167,7 @@ namespace ranges
  sentinel_t<Rng2> end2_;
  public:
  sentinel() = default;
  - sentinel(detail::any, sentinel_t<Rng1> end1, sentinel_t<Rng1> end2)
  + sentinel(detail::any, sentinel_t<Rng1> end1, sentinel_t<Rng2> end2)
  : end1_(std::move(end1)), end2_(std::move(end2))
  {}
  };
  