[3.9] bpo-41688: Document bug in **= dispatching in the language data… (GH-22172)
I tossed in a "This bug is fixed in Python 3.10" sentence but I'm not sure if that's appropriate to have here.
diff --git a/Doc/reference/datamodel.rst b/Doc/reference/datamodel.rst
index a817408..fc304a1 100644
--- a/Doc/reference/datamodel.rst
+++ b/Doc/reference/datamodel.rst
@@ -2409,6 +2409,13 @@
:ref:`faq-augmented-assignment-tuple-error`), but this behavior is in fact
part of the data model.
+ .. note::
+
+ Due to a bug in the dispatching mechanism for ``**=``, a class that
+ defines :meth:`__ipow__` but returns ``NotImplemented`` would fail to
+ fall back to ``x.__pow__(y)`` and ``y.__rpow__(x)``. This bug is fixed
+ in Python 3.10.
+
.. method:: object.__neg__(self)
object.__pos__(self)