> Do you think a senior developer needs a basic understanding of the language they use
4 years ago, I'd have said "obviously".
At this point? Only for specialist languages the LLMs suck at. (Last I tried, "suck at" included going all the way from yacc etc. upwards when trying to make a custom language).
For most of us, what's now important is: Design patterns; architectures; knowing how to think of big-O consequences; and the ability to review what the AI farts out, which sounds like it should need an understanding of the programming language in question, but it's surprisingly straightforward to read code in languages you're not fmiliar with, and it gets even easier when your instruction to the AI includes making the code easy to review.
It’s not just the language but the domain within the language.
I see both the latest Claude and GPT models fall over on a lot of C++, Swift/ObjC and more complex Python code. They do better in codebases where there is maximal context with type hints in the local function. Rust does well, and it’s easier to know when it’s messed up since it won’t compile.
They also tend to clog up code bases with a cacophony of different coding paradigms.
A good developer would be able to see these right away, but someone who doesn’t understand the basics at the least will happily plug along not realizing the wake they’ve left.