Making instance of TypeVar fails because of missing __name__

[jack1142]

BPO	39942
Nosy	@ilevkivskyi, @hongweipeng, @miss-islington, @jack1142
PRs	bpo-39942:Fix TypeVar fails when missing __name__ #19616 [3.7] bpo-39942:Fix failure in TypeVar when missing __name__ (GH-19616) #19626 [3.8] bpo-39942:Fix failure in TypeVar when missing __name__ (GH-19616) #19627

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

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GitHub fields:

assignee = None
closed_at = <Date 2020-04-20.20:28:52.865>
created_at = <Date 2020-03-12.00:11:51.865>
labels = ['3.7', '3.8', 'type-bug', 'library', '3.9']
title = 'Making instance of `TypeVar` fails because of missing `__name__`'
updated_at = <Date 2020-04-20.20:28:52.865>
user = 'https://github.com/jack1142'

bugs.python.org fields:

activity = <Date 2020-04-20.20:28:52.865>
actor = 'levkivskyi'
assignee = 'none'
closed = True
closed_date = <Date 2020-04-20.20:28:52.865>
closer = 'levkivskyi'
components = ['Library (Lib)']
creation = <Date 2020-03-12.00:11:51.865>
creator = 'jack1142'
dependencies = []
files = []
hgrepos = []
issue_num = 39942
keywords = ['patch']
message_count = 4.0
messages = ['363990', '366872', '366874', '366876']
nosy_count = 4.0
nosy_names = ['levkivskyi', 'hongweipeng', 'miss-islington', 'jack1142']
pr_nums = ['19616', '19626', '19627']
priority = 'normal'
resolution = 'fixed'
stage = 'resolved'
status = 'closed'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue39942'
versions = ['Python 3.7', 'Python 3.8', 'Python 3.9']

[jack1142]

Example code:

code = """
import typing
T = typing.TypeVar("T")
"""
exec(code, {})

Traceback:

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "<string>", line 3, in <module>
  File "C:\Python38\lib\typing.py", line 603, in __init__
    def_mod = sys._getframe(1).f_globals['__name__']  # for pickling
KeyError: '__name__'

If this problem with __name__ is not something that needs to be fixed, then I also noticed that the same line in typing.py will also raise when platform doesn't have sys._getframe()

[ilevkivskyi]

New changeset a25a04f by HongWeipeng in branch 'master':
bpo-39942:Fix failure in TypeVar when missing __name__ (GH-19616)
a25a04f

[miss-islington]

New changeset 694a95f by Miss Islington (bot) in branch '3.7':
bpo-39942:Fix failure in TypeVar when missing __name__ (GH-19616)
694a95f

[miss-islington]

New changeset 41660ca by Miss Islington (bot) in branch '3.8':
bpo-39942:Fix failure in TypeVar when missing __name__ (GH-19616)
41660ca