Broken type hints for functions decorated with high_level_function

[chuyuanliu]

Version of Awkward Array

2.7.4

Description and code to reproduce

When using functions like ak.ones_like, ak.almost_equal, the static type checkers (for reference I tested with pylance in vscode and pycharm) are not able to properly resolve the signatures of those functions. Instead, they will always give a (...) -> Any. It is likely because in the type hint for high_level_function the parameters are omitted and the TypeVar("T") is not binded to the decorator. A simple solution is to a ParamSpec in the following way:

from awkward._typing import Any, ParamSpec, TypeAlias, TypeVar

P = ParamSpec("P") # declare a ParamSpec
T = TypeVar("T")
DispatcherType: TypeAlias = "Callable[P, Generator[Collection[Any], None, T]]" # add P
HighLevelType: TypeAlias = "Callable[P, T]" # add P

def high_level_function(
    module: str = "ak", name: str | None = None
) -> Callable[[DispatcherType[P, T]], HighLevelType[P, T]]: # bind P and T to the decorator

[pfackeldey]

Thank @chuyuanliu for reporting this! I'll have a look at it :)