Request: Mark concretely-typed arguments as unusual

[ParadaCarleton]

e.g. Float64 here:

[fredrikekre]

Why?

[ParadaCarleton]

Why?

Sorry, made a mistake in the title--this is for function arguments, although it might also apply (to a slightly lesser extent) to fields in a struct.

The reason I'd like a blue squiggly is because new users often make the mistake of overtyping their functions. It's very rare that you actually need a function to only allow Float64s.

[dzhang314]

I strongly disagree with this suggestion. I write lots of high-performance code (e.g., MultiFloats.jl) that depends on exact bitwise representation, so my functions are correctly and appropriately specialized to concrete types.

Maybe you don't write code like that, and that's fine, but I think this is way too opinionated to turn on in the linter by default.