making the same mistakes

This is key, and I feel like a lot of people arguing about "hallucinations" don't recognize it. Human memory is extremely fallible; we "hallucinate" wrong information all the time. If you've ever forgotten the name of a method, or whether that method even exists in the API you're using, and started typing it out to see if your autocompleter recognizes it, you've just "hallucinated" in the same way an LLM would. The solution isn't to require programmers to have perfect memory, but to have easily-searchable reference information (e.g. the ability to actually read or search through a class's method signatures) and tight feedback loops (e.g. the autocompleter and other LSP/IDE features).