dataclasses.asdict will mangle collection.Counter instances

GitHub fields:

assignee = 'https://github.com/ericvsmith'
closed_at = None
created_at = <Date 2020-03-11.06:13:03.710>
labels = ['3.8', 'type-bug', 'library']
title = 'dataclasses.asdict will mangle collection.Counter instances'
updated_at = <Date 2020-03-11.09:24:12.536>
user = 'https://github.com/bscarlett'

bugs.python.org fields:

activity = <Date 2020-03-11.09:24:12.536>
actor = 'eric.smith'
assignee = 'eric.smith'
closed = False
closed_date = None
closer = None
components = ['Library (Lib)']
creation = <Date 2020-03-11.06:13:03.710>
creator = 'brad.scarlett@gmail.com'
dependencies = []
files = []
hgrepos = []
issue_num = 39929
keywords = []
message_count = 2.0
messages = ['363884', '363893']
nosy_count = 2.0
nosy_names = ['eric.smith', 'brad.scarlett@gmail.com']
pr_nums = []
priority = 'normal'
resolution = None
stage = None
status = 'open'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue39929'
versions = ['Python 3.8']