Depends upon why the code doesn't compile. It is a red flag, and if the student really didn't test it or try to compile it at all that would be a major problem

Depends upon why the code doesn't compile. It is a red flag, and if the student really didn't test it or try to compile it at all that would be a major problem. But even being able to compile code isn't must do in the business world. For example, just today I was fixing a CI/CD pipeline issue where local builds worked fine but the pipeline didn't. I don't think whomever caused the underlying root issue deserves to get fired for that. There are obviously mistakes that go too far, but these generally involve an element of malicious intent. If a junior takes down prod, that's probably a sign that some security settings are missing. Only if they knew they were taking down prod, knew they shouldn't, and did it anyway should something like firing be on the table.