Author Mark.Shannon
Recipients Mark.Shannon, Mohamed_Atef, ethan.furman, gregory.p.smith, gvanrossum, pablogsal, serhiy.storchaka, stestagg
Date 2021-01-12.16:36:23
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Message-id <1610469383.24.0.886633417817.issue42899@roundup.psfhosted.org>
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It's clearer if you rewrite

if a and b:
    ...

as

tmp = a and b
if tmp:
    ...

if a is falsey then bool(a) gets called in `tmp = a and b` and `a` is assigned to `tmp`. Then in `if tmp`, bool(a) is called again.

I agree with you about it not being an optimization if it changes the semantics. But only within agreed semantics.
Optimizations are allow to make fewer calls to __hash__() in a dictionary, or change race conditions, because those are outside of the language specification.
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Date User Action Args
2021-01-12 16:36:23Mark.Shannonsetrecipients: + Mark.Shannon, gvanrossum, gregory.p.smith, ethan.furman, serhiy.storchaka, Mohamed_Atef, pablogsal, stestagg
2021-01-12 16:36:23Mark.Shannonsetmessageid: <1610469383.24.0.886633417817.issue42899@roundup.psfhosted.org>
2021-01-12 16:36:23Mark.Shannonlinkissue42899 messages
2021-01-12 16:36:23Mark.Shannoncreate