The message you receive is not an error, it's a compilation warning. It probably does not cause your solution to fail. If all of your tests are green and you still see this message, then it does not harm your solution in any way, it's still OK. If your tests turn out red, on the other hand, then the mentioned message is not the cause of failure, and your solution is probably incorrect.

Also saying that "tests are OK because 44 users passed them" is the most lame excuse someone can give. It definitely is the issue with C++ version, it simply does not cause tests to fail (probably). But it's still misleading, because when tests fail, then compilation report filled with warnings can put someone looking for the problem on the wrong track.

Making this comment to test if I can read the comment since my question is hidden from me because I haven't solved this kata yet (I think).

I have the same issue(

It's not possible that this is an issue with the cpp version. 44 users have passed the tests.

Please post your code with a spoiler flag and someone famiiar with the language should address your question. And please use the question tag, not the issue tag.

I think there must be an issue with the acceptance test. The basic test is passing fine for me but the remote test is failing with warnings that say warning: comparison of integers of different signs: 'int' and 'std::__cxx11::basic_string<char, std::char_traits, std::allocator >::size_type' (aka 'unsigned long') [-Wsign-compare]. It goes on to reference code that I didn't write. I tried every concievable change to variable types but I keep getting the exact same error.