Implement another useful feature for proxies: in super(X, x), x may
now be a proxy for an X instance, as long as issubclass(x.__class__, X).
diff --git a/Misc/NEWS b/Misc/NEWS
index d88f753..11521c6 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -12,6 +12,9 @@
 Core and builtins
 -----------------
 
+- super(X, x): x may now be a proxy for an X instance, i.e.
+  issubclass(x.__class__, X) but not issubclass(type(x), X).
+
 - isinstance(x, X): if X is a new-style class, this is now equivalent
   to issubclass(type(x), X) or issubclass(x.__class__, X).  Previously
   only type(x) was tested.  (For classic classes this was already the