Default string literals rendered with too many quotes and backlashes

[laurensvalk]

Describe the bug

In overloaded functions, some typed default string literals can be rendered with too many quotes or backlashes:

sep: str = "' '", end: str = "'\\n'"

How to Reproduce

This is a minimal repo created for several Sphinx bug reports.

RTD-theme and napoleon are enabled, but it is also reproducable without them.

$ git clone https://github.com/pybricks/sphinx-issues-minimal
$ cd sphinx-issues-minimal
# Optional if you don't have Sphinx 4.4 and RTD theme  1.0.0 already:
# poetry install
$ make clean html
$ # Open build/html/bugs.html to see above output
$ # See src/bugs/__init__.py for the offending Python source code

Expected behavior

The expected output for the two arguments would be:

sep: str = "", end: str = "\n"

Your project

https://github.com/pybricks/sphinx-issues-minimal

Screenshots

OS

Ubuntu

Python version

3.8.3

Sphinx version

4.4.0

Sphinx extensions

'sphinx.ext.autodoc', 'sphinx.ext.napoleon', 'sphinx_rtd_theme'

Extra tools

No response

Additional context

This was originally posted here: pybricks/pybricks-api#81

[tk0miya]

The root cause of this problem is the same as #10279. This will also be fixed by #10315.