Sebastian Pfitzner

They are. You shouldn't need to explicitly put LinearAlgebra or other stdlibs in your environment.

What environment is selected in VS Code (check the `Julia env: ...` status bar item)?

Yes.

I *think* this only happens with the output renderers in the Jupyter extension. For me this looks correct:  cc @DonJayamanne

Uninstall the Jupyter extension. The notebook UI is (should be) shipped with base VS Code nowadays.

Jupyter frontends *are* supposed to render ANSI color codes correctly, I think.

[Yes.](https://github.com/domluna/JuliaFormatter.jl/issues/501)

What's the `julia.lint.call` option set to in those configs?

I have never seen this pattern of manually subtyping `Function` before, crazy :D Just out of curiousity: Why are you doing this? For being able to dispatch on `ArithmeticFunction`?

I think the typical pattern for that is dispatching on `typeof(add)` (as in `foo(::typeof(add), args...)`).