I'm not saying that you will never find bugs in someone PRs I'm just saying it shouldn't be your first intention, your first intention should be to understand it and be convinced by it. Finding bugs will be a side effect of that. If you reading the code to execute it in your head and find all the weird combination that could trigger a core dump, you should probably check if the author wrote tests for those use cases instead and comment about missing tests. Genuine interest in others work can go a long way compared to imagining how would you solve it like the article author said.