High quality code is not just correct syntax. In fact if the syntax is wrong, it wouldn't be low quality, it simply wouldn't work. Even interns could spot that by running it. But in professional software development environments, you have many additional code requirements like readability, maintainability, overall stability or general good practice patterns. I've seen good engineers deliver high quality code that was still wrong because of some design oversight or misunderstanding - the exact same thing you see from current LLMs. Often you don't even know what is wrong with an approach until you see it cause a problem. But you should still deliver high quality code in the meantime if you want to be good at your job.