whatsnew: LOAD_CLASSDEREF, -X showrefcount

Doc/reference/datamodel.rst

@@ -1647,6 +1647,8 @@ of these candidate metaclasses. If none of the candidate metaclasses meets
 that criterion, then the class definition will fail with ``TypeError``.
 
 
+.. _prepare:
+
 Preparing the class namespace
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 

Doc/whatsnew/3.4.rst

@@ -1455,6 +1455,10 @@ Other Improvements
   now works correctly (previously it silently returned the first python
   module in the file).  (Contributed by Václav Šmilauer in :issue:`16421`.)
 
+* A new opcode, :opcode:`LOAD_CLASSDEREF`, has been added to fix a bug in the
+  loading of free variables in class bodies that could be triggered by certain
+  uses of :ref:`__prepare__ <prepare>`.  (Contributed by Benjamin Peterson in
+  :issue:`17853`.)
 
 
 Significant Optimizations
@@ -1650,6 +1654,10 @@ Changes in 'python' command behavior
   how :envvar:`PATH` works.  The behavior now conforms to the posix convention
   for :envvar:`PATH`.
 
+* The [X refs, Y blocks] output of a debug (``--with-pydebug``) build of the
+  CPython interpreter is now off by default.  It can be re-enabled using the
+  ``-X showrefcount`` option. (Contributed by Ezio Melotti in :issue:`17323`.)
+
 
 Changes in the Python API
 -------------------------