.. _unnecessary-default-type-args:

unnecessary-default-type-args / R6007
=====================================

**Message emitted:**

``Type `%s` has unnecessary default type args. Change it to `%s`.``

**Description:**

*Emitted when types have default type args which can be omitted. Mainly used for `typing.Generator` and `typing.AsyncGenerator`.*

**Problematic code:**

.. literalinclude:: /data/messages/u/unnecessary-default-type-args/bad.py
   :language: python

**Correct code:**

.. literalinclude:: /data/messages/u/unnecessary-default-type-args/good.py
   :language: python

**Configuration file:**

.. literalinclude:: /data/messages/u/unnecessary-default-type-args/pylintrc
    :language: ini

**Additional details:**

At the moment, this check only works for ``Generator`` and ``AsyncGenerator``.

Starting with Python 3.13, the ``SendType`` and ``ReturnType`` default to ``None``.
As such it's no longer necessary to specify them. The ``collections.abc`` variants
don't validate the number of type arguments. Therefore the defaults for these
can be used in earlier versions as well.

**Related links:**

- `Python documentation for AsyncGenerator <https://docs.python.org/3.13/library/typing.html#typing.AsyncGenerator>`_
- `Python documentation for Generator <https://docs.python.org/3.13/library/typing.html#typing.Generator>`_



.. note::
  This message is emitted by the optional :ref:`'typing'<pylint.extensions.typing>`
  checker, which requires the ``pylint.extensions.typing`` plugin to be loaded.

Created by the `typing <https://github.com/pylint-dev/pylint/blob/main/pylint/extensions/typing.py>`__ checker.