Incorrect behavior for functions with keyword-only arguments and **kwargs

Bug Report
mypy reports a arg-type error Argument 2 to "send_command" has incompatible type "**Dict[str, object]"; expected "Optional[float]" [arg-type] for a valid function invocation.

To Reproduce

def send_command(name: str, *, timeout: Optional[float] = None, **params: Any):
    print(name, params, timeout)

send_command("Test", **{"p1": "abc"})

mypy Playground

Expected Behavior
The code above should typecheck without any error.

Actual Behavior
I get the following mypy error:

main.py:7: error: Argument 2 to "send_command" has incompatible type "**Dict[str, str]"; expected "Optional[float]"  [arg-type]

Your Environment

• Mypy version used: 1.3.0
• Mypy command-line flags: None
• Mypy configuration options from mypy.ini (and other config files): None
• Python version used: 3.11

See also

• This python/typing discussion: https://github.com/python/typing/discussions/1406
• Maybe related: #5382

Empieza ejecutando el caso reproducible reportado de Python 3.11 en main.py con mypy 1.3.0 y compara el diagnóstico con el comportamiento esperado. Lee la discusión de typing enlazada y el issue relacionado #5382 para obtener contexto; se considera terminado cuando la llamada válida de solo palabras clave pasa la comprobación de tipos sin un error arg-type.