Consider adding a "TopLevel" keyword that stands in for the top level bound of a corresponding type variable

Summary

Please consider a new typing keyword that stands in for the top level type of a corresponding type variable.

Motivation

Consider a test here and the corresponding definition of DistributionInfo here. The test loses all typing information because I used DistributionInfo[Any, Any, Any]. So if I want typing information, I have to use:

def test_flatten(generator: Generator,
                 distribution_info: DistributionInfo[NaturalParametrization[ExpectationParmetrization, JaxComplexArray],
                                                     ExpectationParametrization[NaturalParmetrization],
                                                     NumpyComplexArray]) -> None:

I would much rather just do

def test_flatten(generator: Generator,
                 distribution_info: DistributionInfo[TopLevel, TopLevel, TopLevel]) -> None:

It's not just shorter, but it reduces churn if the type definitions change. Note that TopLevel is recursive (it chooses the top level of the nested types too).

Commencez par les tests liés tests/test_flatten.py et tests/distribution_info.py afin de comprendre quelles informations de typage sont perdues lorsque DistributionInfo[Any, Any, Any] est utilisé. Clarifiez la sémantique récursive prévue de TopLevel et en quoi elle diffère du comportement existant des variables de type. Le travail sera considéré comme terminé lorsque la proposition contiendra une spécification précise et une voie de validation approuvée.