I've asked this question, and it turns out I had the wrong source file, and that caused the problem.
Wasted my time, wasted other peoples' time.
What do I do now?
If your question doesn't make sense anymore, than you can delete it.
If you just posted the wrong code but you still need an answer to the question, you can edit your question with the correct code
If you've figured out the answer on your own, than you can post that answer to your question and mark it as accepted. You won't get any rep for this, but it can let future users understand the solution to the problem.
Delete the question, and no harm done.
If the question may yet become teachable for the future generations, answer it, accept your own answer, and edit for posterity's sake. That's what I did here - the coding error was all mine, but the error message the compiler was spitting out was wildly misleading. Someone may yet make a similar error and spend countless unproductive hours investigating the error message...
If someone did try to help you and invested their time in trying to solve your problem, which appears to be the case, I would suggest posting a comment acknowledging your error (hard, I know) and then deleting it.
If I was trying to solve a problem being faced by another user, then I would prefer to know what happened, or what had actually gone wrong, rather than having the question deleted without any reason.
Also, I personally think that simply deleting the question would be disrespecting the effort that others are putting in.
You could also upvote an answer or two of theirs' that you think are good, as a way to acknowledge their effort.