--preview flag produces INTERNAL ERROR: f-string expression part cannot include a backslash

[oleksandr-terentiev]

Black v23.1a1

Playground link

Options

--line-length=80
--safe
--preview

Input

my_dict = {"foo": "bar"}
s= f'Lorem Ipsum is simply dummy text of the printing and typesetting industry:\'{my_dict["foo"]}\''

Output

INTERNAL ERROR: Black produced invalid code: f-string expression part cannot include a backslash (<unknown>, line 5). Please report a bug on https://github.com/psf/black/issues.  This invalid output might be helpful: /tmp/blk_5qbr6zhy.log

  File "src/black/__init__.py", line 1324, in assert_equivalent
  File "src/black/parsing.py", line 183, in parse_ast
my_dict = {"foo": "bar"}
s = (
    "Lorem Ipsum is simply dummy text of the printing and typesetting"
    f" industry:'{my_dict[\"foo\"]}'"
)

Expected

my_dict = {"foo": "bar"}
s = (
    "Lorem Ipsum is simply dummy text of the printing and typesetting"
    f" industry:'{my_dict['foo']}'"
)

[yilei]

I'll take a look at this.