Reassigning variable to itself error (WPS434) false positive

[impadalko]

Bug report

What's wrong

Flake8 fails on the following code with the error: WPS434 Found reassigning variable to itself: dx

$ cat test1.py 
"""Incorrect test."""

dx, dy = -dy, dx
$ flake8 test1.py 
test1.py:3:1: WPS434 Found reassigning variable to itself: dx

However, flake8 passes when changing the order of the assignments

$ cat test2.py 
"""Correct test."""

dy, dx = dx, -dy
$ flake8 test2.py
(No output)

How it should be

There is no reassignment, the first case should also pass this rule.

System information

flake8 information

{
  "dependencies": [],
  "platform": {
    "python_implementation": "CPython",
    "python_version": "3.8.5",
    "system": "Linux"
  },
  "plugins": [
    {
      "is_local": false,
      "plugin": "flake8-bandit",
      "version": "2.1.2"
    },
    {
      "is_local": false,
      "plugin": "flake8-broken-line",
      "version": "0.2.1"
    },
    {
      "is_local": false,
      "plugin": "flake8-bugbear",
      "version": "19.8.0"
    },
    {
      "is_local": false,
      "plugin": "flake8-comprehensions",
      "version": "3.3.1"
    },
    {
      "is_local": false,
      "plugin": "flake8-darglint",
      "version": "1.6.0"
    },
    {
      "is_local": false,
      "plugin": "flake8-debugger",
      "version": "3.2.1"
    },
    {
      "is_local": false,
      "plugin": "flake8-docstrings",
      "version": "1.5.0, pydocstyle: 5.1.1"
    },
    {
      "is_local": false,
      "plugin": "flake8-eradicate",
      "version": "0.3.0"
    },
    {
      "is_local": false,
      "plugin": "flake8-string-format",
      "version": "0.2.3"
    },
    {
      "is_local": false,
      "plugin": "flake8_commas",
      "version": "2.0.0"
    },
    {
      "is_local": false,
      "plugin": "flake8_isort",
      "version": "3.0.1"
    },
    {
      "is_local": false,
      "plugin": "flake8_quotes",
      "version": "2.1.2"
    },
    {
      "is_local": false,
      "plugin": "mccabe",
      "version": "0.6.1"
    },
    {
      "is_local": false,
      "plugin": "naming",
      "version": "0.9.1"
    },
    {
      "is_local": false,
      "plugin": "pycodestyle",
      "version": "2.6.0"
    },
    {
      "is_local": false,
      "plugin": "pyflakes",
      "version": "2.2.0"
    },
    {
      "is_local": false,
      "plugin": "radon",
      "version": "4.3.2"
    },
    {
      "is_local": false,
      "plugin": "rst-docstrings",
      "version": "0.0.12"
    },
    {
      "is_local": false,
      "plugin": "wemake_python_styleguide",
      "version": "0.14.1"
    }
  ],
  "version": "3.8.4"
}

pip information

add-trailing-comma==2.0.1
apturl==0.5.2
astor==0.8.1
attrs==20.3.0
autopep8==1.5.4
backcall==0.2.0
bandit==1.7.0
blinker==1.4
boto3==1.16.63
botocore==1.19.63
cachetools==4.2.1
catfish==1.4.13
certifi==2019.11.28
cffi==1.14.4
chardet==3.0.4
Click==7.0
colorama==0.4.3
command-not-found==0.3
cryptography==2.8
cupshelpers==1.0
darglint==1.6.0
dbus-python==1.2.16
decorator==4.4.2
defer==1.0.6
distro==1.4.0
distro-info===0.23ubuntu1
docutils==0.16
ecdsa==0.16.1
entrypoints==0.3
enum34==1.1.6
eradicate==1.0
fake-bpy-module-2.90==20200907
flake8==3.8.4
flake8-bandit==2.1.2
flake8-broken-line==0.2.1
flake8-bugbear==19.8.0
flake8-commas==2.0.0
flake8-comprehensions==3.3.1
flake8-debugger==3.2.1
flake8-docstrings==1.5.0
flake8-eradicate==0.3.0
flake8-isort==3.0.1
flake8-polyfill==1.0.2
flake8-quotes==2.1.2
flake8-rst-docstrings==0.0.12
flake8-string-format==0.2.3
future==0.18.2
gitdb==4.0.5
GitPython==3.1.12
google-api-core==1.25.1
google-api-python-client==1.12.8
google-auth==1.24.0
google-auth-httplib2==0.0.4
google-cloud-core==1.5.0
google-cloud-storage==1.32.0
google-crc32c==1.1.2
google-resumable-media==1.2.0
googleapis-common-protos==1.52.0
httplib2==0.18.1
idna==2.8
ipython==7.20.0
ipython-genutils==0.2.0
isort==4.3.5
jedi==0.18.0
Jinja2==2.11.2
jmespath==0.10.0
keyring==18.0.1
language-selector==0.1
launchpadlib==1.10.13
lazr.restfulclient==0.14.2
lazr.uri==1.0.3
lightdm-gtk-greeter-settings==1.2.2
mando==0.6.4
MarkupSafe==1.1.1
mccabe==0.6.1
menulibre==2.2.1
mugshot==0.4.2
mypy==0.790
mypy-extensions==0.4.3
netifaces==0.10.4
numpy==1.15.1
oauthlib==3.1.0
olefile==0.46
onboard==1.4.1
parso==0.8.1
pbr==5.5.1
pep8-naming==0.9.1
pexpect==4.6.0
pickleshare==0.7.5
Pillow==6.2.0
prompt-toolkit==3.0.14
protobuf==3.14.0
psutil==5.5.1
psycopg2-binary==2.8.2
pyasn1==0.4.8
pyasn1-modules==0.2.8
pycairo==1.16.2
pycodestyle==2.6.0
pycparser==2.20
pycups==1.9.73
pydocstyle==5.1.1
pyflakes==2.2.0
Pygments==2.7.4
PyGObject==3.36.0
PyJWT==1.7.1
pymacaroons==0.13.0
PyNaCl==1.3.0
python-apt==2.0.0+ubuntu0.20.4.4
python-dateutil==2.7.3
python-debian===0.1.36ubuntu1
python-jose==3.1.0
pytz==2021.1
PyYAML==5.3.1
radon==4.3.2
reportlab==3.5.34
requests==2.24.0
requests-unixsocket==0.2.0
restructuredtext-lint==1.3.2
rsa==4.7
s3transfer==0.3.4
screen-resolution-extra==0.0.0
SecretStorage==2.3.1
sgt-launcher==0.2.5
simplejson==3.16.0
six==1.14.0
smmap==3.0.5
snowballstemmer==2.1.0
SQLAlchemy==1.3.8
stevedore==3.3.0
systemd-python==234
testfixtures==6.17.1
tokenize-rt==4.1.0
toml==0.10.2
traitlets==5.0.5
typed-ast==1.4.2
typing-extensions==3.7.4.3
ubuntu-advantage-tools==20.3
ubuntu-drivers-common==0.0.0
ufw==0.36
unify==0.5
untokenize==0.1.1
uritemplate==3.0.1
urllib3==1.25.8
validators==0.18.2
wadllib==1.3.3
wcwidth==0.2.5
wemake-python-styleguide==0.14.1
xcffib==0.8.1
xenon==0.7.1
xkit==0.0.0

[sobolevn]

Thanks for the report!

It is related to: #1807