I've come across a question where the querent has some facts majorly wrong, and they seem to be a substantial cause of the problem they're describing.
I know that we refrain from answering in comments, and I could imagine pointing out those corrections in an answer.
How should I handle pointing out these errors and correcting them? At what point should I point out the corrections in a comment (basically suggesting an improvement), or at what point does that become an answer-in-comments I should instead post an answer for?