28.03.18 19:20, Guido van Rossum пише:

> Hm, without thinking too much about it I'd say it's okay to change the
> evaluation order.

Do you mean the option 3, right? This is the simplest option. I have
already wrote a PR for optimizing old-style formating [1], but have not
merged it yet due to this change of semantic.

> Can these optimizations be disabled with something like -O0?

Currently there is no way to disable optimizations. There is an open
issue with a request for this. [2]

[1] https://github.com/python/cpython/pull/5012
[2] https://bugs.python.org/issue2506