Haven't seen the bug report, but you do realize that comparing code objects has other applications, and this pretty much kills that.
In the OP's situation, two distinct function objects with differing default values were showing up with a non-unique code object. As a result, when the OP's code failed, the traceback message pointed to the wrong like in the file (the first seen function rather than the one executing).
If some other code comparison application is more important, I would be happy to reverse this patch and mark the bug as WON'T FIX.
While the OP's situation did sent him on a wild goose chase (trying to debug the part of his code that did work), I can't imagine that it comes up often enough to care much about.