It's incredible when I ask Claude 3.7 a question about Typescript/Python and it can generate hundreds of lines of code that are pretty on point (it's usually not exactly correct on first prompt, but it's coherent).

I've recently been asking questions about Dafny and Lean -- it's frustrating that it will completely make up syntax and features that don't exist, but still speak to me with the same confidence as when it's talking about Typescript. It's possible that shoving lots of documentation or a book about the language into the context would help (I haven't tried), but I'm not sure if it would make up for the model's lack of "intuition" about the subject.

Don't need to ho that esoteric. Seen them make stuff up pretty often for more common functional programming languages like Haskell and OCaml.