I've noticed while skimming through questions on CodeReview that people are replying with legitimate answers in the comments section, instead of the answers section.
While I've only attached 2 links below, I think if you surf around enough you will see what I mean.
Allow a comment to be promoted (migrated) to an answer. Include the option to auto-accept as the answer for the question.
Other than helping to clarify that the comments are "clarifications", I don't see why we would need to break the implicit flow of what the users do. Just add in the workflow.