Proposed resolution:

This wording is relative to N4910.

1. Modify [fs.class.directory.iterator.general], class directory_iterator synopsis, as indicated:

   namespace std::filesystem {
     class directory_iterator {
       […]
   
       const directory_entry& operator*() const;
       const directory_entry* operator->() const;
       directory_iterator& operator++();
       directory_iterator& increment(error_code& ec);
       
       friend bool operator==(const directory_iterator& lhs, default_sentinel_t) noexcept
       { return lhs == end(lhs); }
   
       // other members as required by [input.iterators], input iterators
     };
   }
   

2. Modify [fs.class.rec.dir.itr.general], class recursive_directory_iterator synopsis, as indicated:

   namespace std::filesystem {
     class recursive_directory_iterator {
       […]
   
       void pop();
       void pop(error_code& ec);
       void disable_recursion_pending();
       
       friend bool operator==(const recursive_directory_iterator& lhs, default_sentinel_t) noexcept
       { return lhs == end(lhs); }
   
       // other members as required by [input.iterators], input iterators
     };
   }
   

We added comparisons with default_sentinel_t to the stream and streambuf iterators, because their past-the-end iterator is just a default-constructed iterator. We didn't do the same for filesystem directory iterators, but they also use a default-constructed value as the sentinel.

The proposed resolution addresses this oversight.