Callable is not colored correctly

[pwall2222]

Callable gets highlighted as any other variable when in fact it is a callable so it would be great if it was highlighted like a function or method, or even just having the option to edit the color of it would be great. (This can't be impossible to do, maybe very hard, because typescript extension does work for this purpose)

Environment data

• Language Server version: 2023.1.10
• OS and version: win32 x64
• Python version: 3.9.4
• python.analysis.indexing: null
• python.analysis.typeCheckingMode: basic

Code Snippet

from typing import Callable


def fn(sub_fn: Callable):
    return sub_fn()

Expected behavior

Actual behavior

[erictraut]

Callable is a special form introduced in PEP 484. It's similar to a protocol class that defines a __call__ method. I think it would be odd to color it the same as functions or methods declared with a def statement.

Incidentally, Callable is intended to be used with two type arguments. The first represents the parameter list and is either ... (ellipsis) or a list of parameter types. The second represents the return type. In your screen shot, you have not provided either of these type arguments. A correct usage would be something like Callable[..., int] or Callable[[int, str], str]. You can see how it acts more like a class than an identifier that refers to a specific function or method.

[pwall2222]

Yea but even if you type it correctly, you still get the same color as if you had any other argument so if you pass it along to another method or you call it directly it doesn't tell you much by looking at it, it solely depends on the name you give it. I mean making it default to use the same color as any other function well maybe it's not the most friendly thing, but having the option to change it would at least be beneficial and up to the user to decide if they want to have the same color or not.

[heejaechang]

sub_fn is a parameter, so we color it as a parameter, same goes for variable fn: Callable ..., fn will be colored as a variable.

but that being said, we could attach token modifier for parameters, variables that are callable so user could customize them if they want to through editor.semanticTokenColorCustomizations

let's put it in the discussion to see user feedbacks.