[issue17973] FAQ entry for: '+=' on a list inside tuple both succeeds and raises an exception

[Ronald Oussoren]

Ronald Oussoren added the comment:

David: your update to the FAQ looks ok to me.


I don't like updating the __setitem__ of tuple to allow setting an identical value (that is 'a[0] = a[0]'), it is a bit too magic to my taste and hides the real problem.

I'd slightly prefer my idea: update the code generated for += to try performing the assignment before calling __iadd__.  I hadn't looked at the AST compiler before, but at first glance implementing my idea seems easier than I had expected and I'm working on an experimental patch.

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