.. _eq-without-hash:

eq-without-hash / W1641
=======================

**Message emitted:**

``Implementing __eq__ without also implementing __hash__``

**Description:**

*Used when a class implements __eq__ but not __hash__. Objects get None as their default __hash__ implementation if they also implement __eq__.*

**Problematic code:**

.. literalinclude:: /data/messages/e/eq-without-hash/bad.py
   :language: python

**Correct code:**

.. literalinclude:: /data/messages/e/eq-without-hash/good.py
   :language: python

**Configuration file:**

.. literalinclude:: /data/messages/e/eq-without-hash/pylintrc
    :language: ini





.. note::
  This message is emitted by the optional :ref:`'eq-without-hash'<pylint.extensions.eq_without_hash>`
  checker, which requires the ``pylint.extensions.eq_without_hash`` plugin to be loaded.

Created by the `eq-without-hash <https://github.com/pylint-dev/pylint/blob/main/pylint/extensions/eq_without_hash.py>`__ checker.