Patch #1623563: allow __class__ assignment for classes with __slots__.
The old and the new class are still required to have the same slot
names, but the order in which they are specified is not relevant.
diff --git a/Doc/ref/ref3.tex b/Doc/ref/ref3.tex
index c5dbfd2..c0f3219 100644
--- a/Doc/ref/ref3.tex
+++ b/Doc/ref/ref3.tex
@@ -1593,6 +1593,11 @@
Mappings may also be used; however, in the future, special meaning may
be assigned to the values corresponding to each key.
+\item \var{__class__} assignment works only if both classes have the
+same \var{__slots__}.
+\versionchanged[Previously, \var{__class__} assignment raised an error
+if either new or old class had \var{__slots__}]{2.6}
+
\end{itemize}
@@ -2223,3 +2228,6 @@
Python \keyword{with} statement.}
\end{seealso}
+
+
+