#4617: Previously it was illegal to delete a name from the local
namespace if it occurs as a free variable in a nested block. This limitation
of the compiler has been lifted, and a new opcode introduced (DELETE_DEREF).
This sample was valid in 2.6, but fails to compile in 3.x without this change::
>>> def f():
... def print_error():
... print(e)
... try:
... something
... except Exception as e:
... print_error()
... # implicit "del e" here
This sample has always been invalid in Python, and now works::
>>> def outer(x):
... def inner():
... return x
... inner()
... del x
There is no need to bump the PYC magic number: the new opcode is used
for code that did not compile before.
diff --git a/Doc/library/dis.rst b/Doc/library/dis.rst
index fb62ec1..8e57dd4 100644
--- a/Doc/library/dis.rst
+++ b/Doc/library/dis.rst
@@ -723,6 +723,12 @@
storage.
+.. opcode:: DELETE_DEREF (i)
+
+ Empties the cell contained in slot *i* of the cell and free variable storage.
+ Used by the :keyword:`del` statement.
+
+
.. opcode:: SET_LINENO (lineno)
This opcode is obsolete.