# HG changeset patch
# User Paul Boddie <paul@boddie.org.uk>
# Date 1489169603 -3600
# Node ID 734bddc017dbd357458ce2b9cfc4ccd46e9359d8
# Parent  6b790fb0924e93dc7d46161e83a066075deb8a38
Prevent __data__ accesses via anonymous accessors from trying to find the
attribute on classes since __data__ is always provided by the immediate object
and because the check_and_load_via_any operation uses a null value internally to
detect failure that can be confused with a genuine __data__ attribute with a
zero value (such as the integer zero).

diff -r 6b790fb0924e -r 734bddc017db deducer.py
--- a/deducer.py	Fri Mar 10 17:57:07 2017 +0100
+++ b/deducer.py	Fri Mar 10 19:13:23 2017 +0100
@@ -2474,10 +2474,15 @@
 
                     if remaining > 1 or final_method in ("access", "access-invoke", "assign"):
 
+                        # Constrain instructions involving certain special
+                        # attribute names.
+
+                        to_search = attrname == "__data__" and "object" or "any"
+
                         if assigning:
-                            emit(("__check_and_store_via_any", accessor, attrname, "<assexpr>"))
+                            emit(("__check_and_store_via_%s" % to_search, accessor, attrname, "<assexpr>"))
                         else:
-                            accessor = ("__check_and_load_via_any", accessor, attrname)
+                            accessor = ("__check_and_load_via_%s" % to_search, accessor, attrname)
 
                     remaining -= 1