Sigh.

Wonder whether there is a story behind Torsten Grust’s comment:

Probably he found that some students just copied the code without understanding how it works?

It’s pretty ridiculous though to use StackOverflow as a way to communicate to students. Doesn’t the school have a course mailing list or something like that?

it’s because the student post homework questions to SO, no?

OK, it’s from https://stackoverflow.com/questions/30775032/transpose-a-matrix-in-racket-list-of-lists

Looking at the question, the poster is definitely a student, using deinprogramm

So, I think it’s not nice that the OP posted homework in StackOverflow like this, if it’s prohibited. On the other hand, I don’t know how clear the course policy is on this matter.

I don’t know what to think about the plagiarism detector for this specific case. Could it be that a student has seen this apply map list before and understand how it works, so they use it? Would that be qualified as cheating?

At least in my area, that would be very frowned upon if not downright cheating. Course policies generally ban online resources, with the exceptions of those listed (e.g., racket docs is probably ok, but SO & co. is usually not). re: plagiarism, I wonder if perhaps they meant the later transpose? Of course, the exact simple transpose may be an issue, too, for some professors

I likely wouldn’t bother about it unless it were one instance of a widespread issue with that student

FWIW the question is 5 years old, but the comment is recent.