Great effort in putting together this large corpus! While reading through your paper, I noticed the difficulties you faced in correctly annotating the code for their quality, correctness and hiring annotators for different languages. I can imagine how herculean this task could be.

I was wondering if you thought to include stackoverflow questions and answers, which have been vetted by thousands of programmers over a long period of time. Stackoverflow might even want to participate in this effort to provide a clean ground truth for this great project.