#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/Include/opcode.h b/Include/opcode.h
index 1114c93..6b10944 100644
--- a/Include/opcode.h
+++ b/Include/opcode.h
@@ -123,6 +123,7 @@
#define LOAD_CLOSURE 135 /* Load free variable from closure */
#define LOAD_DEREF 136 /* Load and dereference from closure cell */
#define STORE_DEREF 137 /* Store into cell */
+#define DELETE_DEREF 138 /* Delete closure cell */
/* The next 3 opcodes must be contiguous and satisfy
(CALL_FUNCTION_VAR - CALL_FUNCTION) & 3 == 1 */