On 16 Apr 2021, at 16:59, Guido van Rossum wrote:

If you look deeper, the real complaints are all about the backwards
incompatibility when it comes to locally-scoped types in annotations. I.e.

def test():
class C: ...
def func(arg: C): ...
return func

typing.get_type_hints(test()) # raises NameError: name 'C' is not defined

Can't this be solved by wrapping the annotation in a lambda, i.e.

>>> def test():
...   class C: ...
...   def func(arg: lambda: C): ...
...   return func
...
>>> test().__annotations__['arg']()
<class '__main__.test.<locals>.C'>

So typing.get_type_hints() would simply call an annotation if the annotation was callable and replace it with the result of the call.