#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/Lib/opcode.py b/Lib/opcode.py
index 9833b6c..8e15d13 100644
--- a/Lib/opcode.py
+++ b/Lib/opcode.py
@@ -161,6 +161,8 @@
hasfree.append(136)
def_op('STORE_DEREF', 137)
hasfree.append(137)
+def_op('DELETE_DEREF', 138)
+hasfree.append(138)
def_op('CALL_FUNCTION_VAR', 140) # #args + (#kwargs << 8)
def_op('CALL_FUNCTION_KW', 141) # #args + (#kwargs << 8)