Access checks now work, at least for instance data (not for methods yet). The class is now passed to eval_code and stored in the current frame. It is also stored in instance method objects. An "unbound" instance method is now returned when a function is retrieved through "classname.funcname", which when called passes the class to eval_code.

--- a/Python/pythonrun.c	Wed May 19 14:50:45 1993 +0000
+++ b/Python/pythonrun.c	Thu May 20 14:24:46 1993 +0000
@@ -320,7 +320,7 @@
 	freetree(n);
 	if (co == NULL)
 		return NULL;
-	v = eval_code(co, globals, locals, (object *)NULL);
+	v = eval_code(co, globals, locals, (object *)NULL, (object *)NULL);
 	DECREF(co);
 	return v;
 }