Leaving aside the apparent confusion between C and C++, do you really imply overloading could make adding two fixed size numbers in Python take unbounded time?

I'm saying a + b in Python can do whatever you override the __add__/__radd__ to. Not sure why you invoke C/C++ here.

If you only limit yourself to numbers (the title doesn't specify that) it should be bounded, but the article goes into some depth here, so I'll leave it at that.

But this has nothing to do with the halting problem. You can run the code, you don't need to do this theoretically.

Fair!

No. All you need to do is use a code coverage tool to find out which lines are run.