Incorrect overload parameter mismatch when typing decorator

[max-kamps]

Describe the bug
Trying to type a decorator, and I'm running into some seemingly spurious errors. I've tried to figure out what exactly causes this, to no avail.

The goal is to have the an optional cls parameter, and to have the return type vary based on whether it is present or absent. Mypy accepts the following code, but Pyright does not.

Apologies if this has already been reported, but I couldn't find any existing issue.

**Code **

Pyright playground

Mypy playground

from typing import overload, Callable

@overload
def decorator[T](cls: type[T], /, *, extra: int = 0) -> type[T]:
    ...

@overload
def decorator[T](cls: None = None, /, *, extra: int = 0) -> Callable[[type[T]], type[T]]:
    ...

def decorator[T](cls: type[T] | None = None, /, *, extra: int = 0):
    if cls is None:
        def wrapper(cls: type[T]) -> type[T]:
            return decorator(cls, extra=extra)
        return wrapper
    
    setattr(cls, "__extra__", extra)
    return cls

Pyright error message:

Overloaded implementation is not consistent with signature of overload 2
  Function return type "(type[T@decorator]) -> type[T@decorator]" is incompatible with type "((cls: type[T@decorator]) -> type[T@decorator]) | type[T@decorator]"
    Type "(type[T@decorator]) -> type[T@decorator]" is not assignable to type "((cls: type[T@decorator]) -> type[T@decorator]) | type[T@decorator]"
      Type "(type[T@decorator]) -> type[T@decorator]" is not assignable to type "type[T@decorator]"
      Type "(type[T@decorator]) -> type[T@decorator]" is not assignable to type "(cls: type[T@decorator]) -> type[T@decorator]"
        Missing keyword parameter "cls"
          Position-only parameter mismatch; parameter "cls" is not position-only
          Position-only parameter mismatch; expected 1 but received 0  (reportInconsistentOverload)

[bschnurr]

adding a return type annotation fixes it . but i'm not sure why

from typing import overload, Callable

@overload
def decorator[T](cls: type[T], /, *, extra: int = 0) -> type[T]:
    ...

@overload
def decorator[T](cls: None = None, /, *, extra: int = 0) -> Callable[[type[T]], type[T]]:
    ...

def decorator[T](cls: type[T] | None = None, /, *, extra: int = 0) -> type[T] | Callable[[type[T]], type[T]]:
    if cls is None:
        def wrapper(cls: type[T]) -> type[T]:
            return decorator(cls, extra=extra)
        return wrapper
    
    setattr(cls, "__extra__", extra)
    return cls

and maybe the Pylance function hover has some insight.